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  • to understand the code- how the heap is written in process migration in solaris

    - by akshay
    hi guys i need help understanding what this piece of code actually does as it is a part of my project i am stuck here. the code is from libckpt on solaris. /********************************** * function: write_heap * args: map_fd -- file descriptor for map file * data_fd -- file descriptor for data file * returns: no. of chunks written on success, -1 on failure * side effects: writes all included segments of the heap to ckpt files * misc.: If we are forking and copyonwrite is set, we will write the heap from bottom to top, moving the brk pointer up each time so that we don't get a page copied if the * called from: take_ckpt() ***********************************/ static int write_heap(int map_fd, int data_fd) { Dlist curptr, endptr; int no_chunks=0, pn; long size; caddr_t stop, addr; if(ckptflags.incremental){ /-- incremental checkpointing on? --/ endptr = ckptglobals.inc_list-main-flink; /*-- for each included chunk of the heap --*/ for(curptr = ckptglobals.inc_list->main->blink->blink; curptr != endptr; curptr = curptr->blink){ /*-- write out the last page in the included chunk --*/ stop = curptr->addr; pn = ((long)curptr->stop - (long)sys.DATASTART) / PAGESIZE; if(isdirty(pn)){ addr = (caddr_t)max((long)curptr->addr, (long)((pn * PAGESIZE) + sys.DATASTART)); size = (long)curptr->stop - (long)addr; debug(stderr, "DEBUG: Writing heap from 0x%x to 0x%x, pn = %d\n", addr, addr+size, pn); if(write_chunk(addr, size, map_fd, data_fd) == -1){ return -1; } if((int)addr > (int)(&end) && ckptflags.enhanced_fork){ brk(addr); } no_chunks++; } /*-- write out all the whole pages in the middle of the chunk --*/ for(pn--; pn * PAGESIZE + sys.DATASTART >= stop; pn--){ if(isdirty(pn)){ addr = (caddr_t)((pn * PAGESIZE) + sys.DATASTART); debug(stderr, "DEBUG: Writing heap from 0x%x to 0x%x, pn = %d\n", addr, addr+PAGESIZE, pn); if(write_chunk(addr, PAGESIZE, map_fd, data_fd) == -1){ return -1; } if((int)addr > (int)(&end) && ckptflags.enhanced_fork){ brk(addr); } no_chunks++; } } /*-- write out the first page in the included chunk --*/ addr = curptr->addr; size = ((pn+1) * PAGESIZE + sys.DATASTART) - addr; if(size > 0 && (isdirty(pn))){ debug(stderr, "DEBUG: Writing heap from 0x%x to 0x%x\n", addr, addr+size); if(write_chunk(addr, size, map_fd, data_fd) == -1){ return -1; } if((int)addr > (int)(&end) && ckptflags.enhanced_fork){ brk(addr); } no_chunks++; } } } else{ /-- incremental checkpointing off! --/ endptr = ckptglobals.inc_list-main-blink; /*-- for each included chunk of the heap --*/ for(curptr = ckptglobals.inc_list->main->flink->flink; curptr != endptr; curptr = curptr->flink){ debug(stderr, "DEBUG: saving memory from 0x%x to 0x%x\n", curptr->addr, curptr->addr+curptr->size); if(write_chunk(curptr->addr, curptr->size, map_fd, data_fd) == -1){ return -1; } if((int)addr > (int)(&end) && ckptflags.enhanced_fork){ brk(addr); } no_chunks++; } } return no_chunks; }

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  • Help to restructure my Doc/View more correctly

    - by Harvey
    Edited by OP. My program is in need of a lot of cleanup and restructuring. In another post I asked about leaving the MFC DocView framework and going to the WinProc & Message Loop way (what is that called for short?). Well at present I am thinking that I should clean up what I have in Doc View and perhaps later convert to non-MFC it that even makes sense. My Document class currently has almost nothing useful in it. I think a place to start is the InitInstance() function (posted below). In this part: POSITION pos=pDocTemplate->GetFirstDocPosition(); CLCWDoc *pDoc=(CLCWDoc *)pDocTemplate->GetNextDoc(pos); ASSERT_VALID(pDoc); POSITION vpos=pDoc->GetFirstViewPosition(); CChildView *pCV=(CChildView *)pDoc->GetNextView(vpos); This seem strange to me. I only have one doc and one view. I feel like I am going about it backwards with GetNextDoc() and GetNextView(). To try to use a silly analogy; it's like I have a book in my hand but I have to look up in it's index to find out what page the Title of the book is on. I'm tired of feeling embarrassed about my code. I either need correction or reassurance, or both. :) Also, all the miscellaneous items are in no particular order. I would like to rearrange them into an order that may be more standard, structured or straightforward. ALL suggestions welcome! BOOL CLCWApp::InitInstance() { InitCommonControls(); if(!AfxOleInit()) return FALSE; // Initialize the Toolbar dll. (Toolbar code by Nikolay Denisov.) InitGuiLibDLL(); // NOTE: insert GuiLib.dll into the resource chain SetRegistryKey(_T("Real Name Removed")); // Register document templates CSingleDocTemplate* pDocTemplate; pDocTemplate = new CSingleDocTemplate( IDR_MAINFRAME, RUNTIME_CLASS(CLCWDoc), RUNTIME_CLASS(CMainFrame), RUNTIME_CLASS(CChildView)); AddDocTemplate(pDocTemplate); // Parse command line for standard shell commands, DDE, file open CCmdLineInfo cmdInfo; ParseCommandLine(cmdInfo); // Dispatch commands specified on the command line // The window frame appears on the screen in here. if (!ProcessShellCommand(cmdInfo)) { AfxMessageBox("Failure processing Command Line"); return FALSE; } POSITION pos=pDocTemplate->GetFirstDocPosition(); CLCWDoc *pDoc=(CLCWDoc *)pDocTemplate->GetNextDoc(pos); ASSERT_VALID(pDoc); POSITION vpos=pDoc->GetFirstViewPosition(); CChildView *pCV=(CChildView *)pDoc->GetNextView(vpos); if(!cmdInfo.m_Fn1.IsEmpty() && !cmdInfo.m_Fn2.IsEmpty()) { pCV->OpenF1(cmdInfo.m_Fn1); pCV->OpenF2(cmdInfo.m_Fn2); pCV->DoCompare(); // Sends a paint message when complete } // enable file manager drag/drop and DDE Execute open m_pMainWnd->DragAcceptFiles(TRUE); m_pMainWnd->ShowWindow(SW_SHOWNORMAL); m_pMainWnd->UpdateWindow(); // paints the window background pCV->bDoSize=true; //Prevent a dozen useless size calculations return TRUE; } Thanks

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  • How to Force an Exception from a Task to be Observed in a Continuation Task?

    - by Richard
    I have a task to perform an HttpWebRequest using Task<WebResponse>.Factory.FromAsync(req.BeginGetRespone, req.EndGetResponse) which can obviously fail with a WebException. To the caller I want to return a Task<HttpResult> where HttpResult is a helper type to encapsulate the response (or not). In this case a 4xx or 5xx response is not an exception. Therefore I've attached two continuations to the request task. One with TaskContinuationOptions OnlyOnRanToCompletion and the other with OnlyOnOnFaulted. And then wrapped the whole thing in a Task<HttpResult> to pick up the one result whichever continuation completes. Each of the three child tasks (request plus two continuations) is created with the AttachedToParent option. But when the caller waits on the returned outer task, an AggregateException is thrown is the request failed. I want to, in the on faulted continuation, observe the WebException so the client code can just look at the result. Adding a Wait in the on fault continuation throws, but a try-catch around this doesn't help. Nor does looking at the Exception property (as section "Observing Exceptions By Using the Task.Exception Property" hints here). I could install a UnobservedTaskException event handler to filter, but as the event offers no direct link to the faulted task this will likely interact outside this part of the application and is a case of a sledgehammer to crack a nut. Given an instance of a faulted Task<T> is there any means of flagging it as "fault handled"? Simplified code: public static Task<HttpResult> Start(Uri url) { var webReq = BuildHttpWebRequest(url); var result = new HttpResult(); var taskOuter = Task<HttpResult>.Factory.StartNew(() => { var tRequest = Task<WebResponse>.Factory.FromAsync( webReq.BeginGetResponse, webReq.EndGetResponse, null, TaskCreationOptions.AttachedToParent); var tError = tRequest.ContinueWith<HttpResult>( t => HandleWebRequestError(t, result), TaskContinuationOptions.AttachedToParent |TaskContinuationOptions.OnlyOnFaulted); var tSuccess = tRequest.ContinueWith<HttpResult>( t => HandleWebRequestSuccess(t, result), TaskContinuationOptions.AttachedToParent |TaskContinuationOptions.OnlyOnRanToCompletion); return result; }); return taskOuter; } with: private static HttpDownloaderResult HandleWebRequestError( Task<WebResponse> respTask, HttpResult result) { Debug.Assert(respTask.Status == TaskStatus.Faulted); Debug.Assert(respTask.Exception.InnerException is WebException); // Try and observe the fault: Doesn't help. try { respTask.Wait(); } catch (AggregateException e) { Log("HandleWebRequestError: waiting on antecedent task threw inner: " + e.InnerException.Message); } // ... populate result with details of the failure for the client ... return result; } (HandleWebRequestSuccess will eventually spin off further tasks to get the content of the response...) The client should be able to wait on the task and then look at its result, without it throwing due to a fault that is expected and already handled.

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  • How to design a C / C++ library to be usable in many client languages?

    - by Brian Schimmel
    I'm planning to code a library that should be usable by a large number of people in on a wide spectrum of platforms. What do I have to consider to design it right? To make this questions more specific, there are four "subquestions" at the end. Choice of language Considering all the known requirements and details, I concluded that a library written in C or C++ was the way to go. I think the primary usage of my library will be in programs written in C, C++ and Java SE, but I can also think of reasons to use it from Java ME, PHP, .NET, Objective C, Python, Ruby, bash scrips, etc... Maybe I cannot target all of them, but if it's possible, I'll do it. Requirements It would be to much to describe the full purpose of my library here, but there are some aspects that might be important to this question: The library itself will start out small, but definitely will grow to enormous complexity, so it is not an option to maintain several versions in parallel. Most of the complexity will be hidden inside the library, though The library will construct an object graph that is used heavily inside. Some clients of the library will only be interested in specific attributes of specific objects, while other clients must traverse the object graph in some way Clients may change the objects, and the library must be notified thereof The library may change the objects, and the client must be notified thereof, if it already has a handle to that object The library must be multi-threaded, because it will maintain network connections to several other hosts While some requests to the library may be handled synchronously, many of them will take too long and must be processed in the background, and notify the client on success (or failure) Of course, answers are welcome no matter if they address my specific requirements, or if they answer the question in a general way that matters to a wider audience! My assumptions, so far So here are some of my assumptions and conclusions, which I gathered in the past months: Internally I can use whatever I want, e.g. C++ with operator overloading, multiple inheritance, template meta programming... as long as there is a portable compiler which handles it (think of gcc / g++) But my interface has to be a clean C interface that does not involve name mangling Also, I think my interface should only consist of functions, with basic/primitive data types (and maybe pointers) passed as parameters and return values If I use pointers, I think I should only use them to pass them back to the library, not to operate directly on the referenced memory For usage in a C++ application, I might also offer an object oriented interface (Which is also prone to name mangling, so the App must either use the same compiler, or include the library in source form) Is this also true for usage in C# ? For usage in Java SE / Java EE, the Java native interface (JNI) applies. I have some basic knowledge about it, but I should definitely double check it. Not all client languages handle multithreading well, so there should be a single thread talking to the client For usage on Java ME, there is no such thing as JNI, but I might go with Nested VM For usage in Bash scripts, there must be an executable with a command line interface For the other client languages, I have no idea For most client languages, it would be nice to have kind of an adapter interface written in that language. I think there are tools to automatically generate this for Java and some others For object oriented languages, it might be possible to create an object oriented adapter which hides the fact that the interface to the library is function based - but I don't know if its worth the effort Possible subquestions is this possible with manageable effort, or is it just too much portability? are there any good books / websites about this kind of design criteria? are any of my assumptions wrong? which open source libraries are worth studying to learn from their design / interface / souce? meta: This question is rather long, do you see any way to split it into several smaller ones? (If you reply to this, do it as a comment, not as an answer)

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  • [C#] Not enough memory or not enough handles?

    - by Nayan
    I am working on a large scale project where a custom (pretty good and robust) framework has been provided and we have to use that for showing up forms and views. There is abstract class StrategyEditor (derived from some class in framework) which is instantiated whenever a new StrategyForm is opened. StrategyForm (a customized window frame) contains StrategyEditor. StrategyEditor contains StrategyTab. StrategyTab contains StrategyCanvas. This is a small portion of the big classes to clarify that there are many objects that will be created if one StrategyForm object is allocated in memory at run-time. My component owns all these classes mentioned above except StrategyForm whose code is not in my control. Now, at run-time, user opens up many strategy objects (which trigger creation of new StrategyForm object.) After creating approx. 44 strategy objects, we see that the USER OBJECT HANDLES (I'll use UOH from here onwards) created by the application reaches to about 20k+, while in registry the default amount for handles is 10k. Read more about User Objects here. Testing on different machines made it clear that the number of strategy objects opened is different for message to pop-up - on one m/c if it is 44, then it can be 40 on another. When we see the message pop-up, it means that the application is going to respond slowly. It gets worse with few more objects and then creation of window frames and subsequent objects fail. We first thought that it was not-enough-memory issue. But then reading more about new in C# helped in understanding that an exception would be thrown if app ran out of memory. This is not a memory issue then, I feel (task manager also showed 1.5GB+ available memory.) M/C specs Core 2 Duo 2GHz+ 4GB RAM 80GB+ free disk space for page file Virtual Memory set: 4000 - 6000 My questions Q1. Does this look like a memory issue and I am wrong that it is not? Q2. Does this point to exhaustion of free UOHs (as I'm thinking) and which is resulting in failure of creation of window handles? Q3. How can we avoid loading up of an StrategyEditor object (beyond a threshold, keeping an eye on the current usage of UOHs)? (we already know how to fetch number of UOHs in use, so don't go there.) Keep in mind that the call to new StrategyForm() is outside the control of my component. Q4. I am bit confused - what are Handles to user objects exactly? Is MSDN talking about any object that we create or only some specific objects like window handles, cursor handles, icon handles? Q5. What exactly cause to use up a UOH? (almost same as Q4) I would be really thankful to anyone who can give me some knowledgeable answers. Thanks much! :)

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  • Recommended integration mechanism for bi-directional, authenticated, encrypted connection in C clien

    - by rcampbell
    Let me first give an example. Imagine you have a single server running a JVM application. This server keeps a collection of N equations, once for each client: Client #1: 2x Client #2: 1 + y Client #3: z/4 This server includes an HTTP interface so that random visitors can type https://www.acme.com/client/3 int their browsers and see the latest evaluated result of z/4. The tricky part is that either the client or the server may change the variable value at any time, informing the other party immediately. More specifically, Client #3 - a C app - can initially tell the server that z = 20. An hour later that same client informs the server that z = 23. Likewise the server can later inform the client that z = 28. As caf pointed out in the comments, there can be a race condition when values are changed by the client and server simultaneously. The solution would be for both client and server to send the operation performed in their message, which would need to be executed by the other party. To keep things simple, let's limit the operations to (commutative) addition, allowing us to disregard message ordering. For example, the client seeds the server with z = 20: server:z=20, client:z=20 server sends {+3} message (so z=23 locally) & client sends {-2} message (so z=18 locally) at the exact same time server receives {-2} message at some point, adds to his local copy so z=21 client receives {+3} message at some point, adds to his local copy so z=21 As long as all messages are eventually evaluated by both parties, the correct answer will eventually be given to the users of the client and server since we limited ourselves to commutative operations (addition of 3 and -2). This does mean that both client and server can be returning incorrect answers in the time it takes for messages to be exchanged and processed. While undesirable, I believe this is unavoidable. Some possible implementations of this idea include: Open an encrypted, always on TCP socket connection for communication Pros: no additional infrastructure needed, client and server know immediately if there is a problem (disconnect) with the other party, fairly straightforward (except the the encryption), native support from both JVM and C platforms Cons: pretty low-level so you end up writing a lot yourself (protocol, delivery verification, retry-on-failure logic), probably have a lot of firewall headaches during client app installation Asynchronous messaging (ex: ActiveMQ) Pros: transactional, both C & Java integration, free up the client and server apps from needing retry logic or delivery verification, pretty straightforward encryption, easy extensibility via message filters/routers/etc Cons: need additional infrastructure (message server) which must never fail, Database or file system as asynchronous integration point Same pros/cons as above but messier RESTful Web Service Pros: simple, possible reuse of the server's existing REST API, SSL figures out the encryption problem for you (maybe use RSA key a la GitHub for authentication?) Cons: Client now needs to run a C HTTP REST server w/SSL, client and server need retry logic. Axis2 has both a Java and C version, but you may be limited to SOAP. What other techniques should I be evaluating? What real world experiences have you had with these mechanisms? Which do you recommend for this problem and why?

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  • Trouble in ActiveX multi-thread invoke javascript callback routine

    - by code0tt
    everyone. I'm get some trouble in ActiveX programming with ATL. I try to make a activex which can async-download files from http server to local folder and after download it will invoke javascript callback function. My solution: run a thread M to monitor download thread D, when D is finish the job, M is going to terminal themself and invoke IDispatch inferface to call javascript function. **************** THERE IS MY CODE: **************** /* javascript code */ funciton download() { var xfm = new ActiveXObject("XFileMngr.FileManager.1"); xfm.download( 'http://somedomain/somefile','localdev:\\folder\localfile',function(msg){alert(msg);}); } /* C++ code */ // main routine STDMETHODIMP CFileManager::download(BSTR url, BSTR local, VARIANT scriptCallback) { CString csURL(url); CString csLocal(local); CAsyncDownload download; download.Download(this, csURL, csLocal, scriptCallback); return S_OK; } // parts of CAsyncDownload.h typedef struct tagThreadData { CAsyncDownload* pThis; } THREAD_DATA, *LPTHREAD_DATA; class CAsyncDownload : public IBindStatusCallback { private: LPUNKNOWN pcaller; CString csRemoteFile; CString csLocalFile; CComPtr<IDispatch> spCallback; public: void onDone(HRESULT hr); HRESULT Download(LPUNKNOWN caller, CString& csRemote, CString& csLocal, VARIANT callback); static DWORD __stdcall ThreadProc(void* param); }; // parts of CAsyncDownload.cpp void CAsyncDownload::onDone(HRESULT hr) { if(spCallback) { TRACE(TEXT("invoke callback function\n")); CComVariant vParams[1]; vParams[0] = "callback is working!"; DISPPARAMS params = { vParams, NULL, 1, 0 }; HRESULT hr = spCallback->Invoke(0, IID_NULL, LOCALE_USER_DEFAULT, DISPATCH_METHOD, &params, NULL, NULL, NULL); if(FAILED(hr)) { CString csBuffer; csBuffer.Format(TEXT("invoke failed, result value: %d \n"),hr); TRACE(csBuffer); }else { TRACE(TEXT("invoke was successful\n")); } } } HRESULT CAsyncDownload::Download(LPUNKNOWN caller, CString& csRemote, CString& csLocal, VARIANT callback) { CoInitializeEx(NULL, COINIT_MULTITHREADED); csRemoteFile = csRemote; csLocalFile = csLocal; pcaller = caller; switch(callback.vt){ case VT_DISPATCH: case VT_VARIANT:{ spCallback = callback.pdispVal; } break; default:{ spCallback = NULL; } } LPTHREAD_DATA pData = new THREAD_DATA; pData->pThis = this; // create monitor thread M HANDLE hThread = CreateThread(NULL, 0, ThreadProc, (void*)(pData), 0, NULL); if(!hThread) { delete pData; return HRESULT_FROM_WIN32(GetLastError()); } WaitForSingleObject(hThread, INFINITE); CloseHandle(hThread); CoUninitialize(); return S_OK; } DWORD __stdcall CAsyncDownload::ThreadProc(void* param) { LPTHREAD_DATA pData = (LPTHREAD_DATA)param; // here, we will create http download thread D // when download job is finish, call onDone method; pData->pThis->onDone(S_OK); delete pData; return 0; } **************** CODE FINISH **************** OK, above is parts of my source code, if I call onDone method in sub-thread, I will get OLE ERROR(-2147418113 (8000FFFF) Catastrophic failure.). Did I miss something? please help me to figure it out.

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  • inserting new relationship data in core-data

    - by michael
    My app will allow users to create a personalised list of events from a large list of events. I have a table view which simply displays these events, tapping on one of them takes the user to the event details view, which has a button "add to my events". In this detailed view I own the original event object, retrieved via an NSFetchedResultsController and passed to the detailed view (via a table cell, the same as the core data recipes sample). I have no trouble retrieving/displaying information from this "event". I am then trying to add it to the list of MyEvents represented by a one to many (inverse) relationship: This code: NSManagedObjectContext *context = [event managedObjectContext]; MyEvents *myEvents = (MyEvents *)[NSEntityDescription insertNewObjectForEntityForName:@"MyEvents" inManagedObjectContext:context]; [myEvents addEventObject:event];//ERROR And this code (suggested below): //would this add to or overwrite the "list" i am attempting to maintain NSManagedObjectContext *context = [event managedObjectContext]; MyEvents *myEvents = (MyEvents *)[NSEntityDescription insertNewObjectForEntityForName:@"MyEvents" inManagedObjectContext:context]; NSMutableSet *myEvent = [myEvents mutableSetValueForKey:@"event"]; [myEvent addObject:event]; //ERROR Bot produce (at the line indicated by //ERROR): *** -[NSComparisonPredicate evaluateWithObject:]: message sent to deallocated instance Seems I may have missed something fundamental. I cant glean any more information through the use of debugging tools, with my knowledge of them. 1) Is this a valid way to compile and store an editable list like this? 2) Is there a better way? 3) What could possibly be the deallocated instance in error? -- I have now modified the Event entity to have a to-many relationship called "myEvents" which referrers to itself. I can add Events to this fine, and logging the object shows the correct memory addresses appearing for the relationship after a [event addMyEventObject:event];. The same failure happens right after this however. I am still at a loss to understand what is going wrong. This is the backtrace #0 0x01f753a7 in ___forwarding___ () #1 0x01f516c2 in __forwarding_prep_0___ () #2 0x01c5aa8f in -[NSFetchedResultsController(PrivateMethods) _preprocessUpdatedObjects:insertsInfo:deletesInfo:updatesInfo:sectionsWithDeletes:newSectionNames:treatAsRefreshes:] () #3 0x01c5d63b in -[NSFetchedResultsController(PrivateMethods) _managedObjectContextDidChange:] () #4 0x0002e63a in _nsnote_callback () #5 0x01f40005 in _CFXNotificationPostNotification () #6 0x0002bef0 in -[NSNotificationCenter postNotificationName:object:userInfo:] () #7 0x01bbe17d in -[NSManagedObjectContext(_NSInternalNotificationHandling) _postObjectsDidChangeNotificationWithUserInfo:] () #8 0x01c1d763 in -[NSManagedObjectContext(_NSInternalChangeProcessing) _createAndPostChangeNotification:withDeletions:withUpdates:withRefreshes:] () #9 0x01ba25ea in -[NSManagedObjectContext(_NSInternalChangeProcessing) _processRecentChanges:] () #10 0x01bdfb3a in -[NSManagedObjectContext processPendingChanges] () #11 0x01bd0957 in _performRunLoopAction () #12 0x01f4d252 in __CFRunLoopDoObservers () #13 0x01f4c65f in CFRunLoopRunSpecific () #14 0x01f4bc48 in CFRunLoopRunInMode () #15 0x0273878d in GSEventRunModal () #16 0x02738852 in GSEventRun () #17 0x002ba003 in UIApplicationMain () solution I managed to get to the bottom of this. I was fetching the event in question using a NSFetchedResultsController with a NSPredicate which I was releasing after I had the results. Retrieving values from the entities returned was no problem, but when I tried to update any of them it gave the error above. It should not have been released. oustanding part of my question What is a good way to create this sub list from a list of existing items in terms of a core data model. I don't believe its any of the ways I tried here. I need to show/edit it in another table view. Perhaps there is a better way than a boolean property on each event entity? The relationship idea above doesn't seem to work here (even though I can now create it). Cheers.

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  • What does the `forall` keyword in Haskell/GHC do?

    - by JUST MY correct OPINION
    I've been banging my head on this one for (quite literally) years now. I'm beginning to kinda/sorta understand how the foreach keyword is used in so-called "existential types" like this: data ShowBox = forall s. Show s => SB s (This despite the confusingly-worded explanations of it in the fragments found all around the web.) This is only a subset, however, of how foreach is used and I simply cannot wrap my mind around its use in things like this: runST :: forall a. (forall s. ST s a) -> a Or explaining why these are different: foo :: (forall a. a -> a) -> (Char,Bool) bar :: forall a. ((a -> a) -> (Char, Bool)) Or the whole RankNTypes stuff that breaks my brain when "explained" in a way that makes me want to do that Samuel L. Jackson thing from Pulp Fiction. (Don't follow that link if you're easily offended by strong language.) The problem, really, is that I'm a dullard. I can't fathom the chicken scratchings (some call them "formulae") of the elite mathematicians that created this language seeing as my university years are over two decades behind me and I never actually had to put what I learnt into use in practice. I also tend to prefer clear, jargon-free English rather than the kinds of language which are normal in academic environments. Most of the explanations I attempt to read on this (the ones I can find through search engines) have these problems: They're incomplete. They explain one part of the use of this keyword (like "existential types") which makes me feel happy until I read code that uses it in a completely different way (like runST, foo and bar above). They're densely packed with assumptions that I've read the latest in whatever branch of discrete math, category theory or abstract algebra is popular this week. (If I never read the words "consult the paper whatever for details of implementation" again, it will be too soon.) They're written in ways that frequently turn even simple concepts into tortuously twisted and fractured grammar and semantics. (I suspect that the last two items are the biggest problem. I wouldn't know, though, since I'm too much a dullard to comprehend them.) It's been asked why Haskell never really caught on in industry. I suspect, in my own humble, unintelligent way, that my experience in figuring out one stupid little keyword -- a keyword that is increasingly ubiquitous in the libraries being written these days -- are also part of the answer to that question. It's hard for a language to catch on when even its individual keywords cause years-long quests to comprehend. Years-long quests which end in failure. So... On to the actual question. Can anybody completely explain the foreach keyword in clear, plain English (or, if it exists somewhere, point to such a clear explanation which I've missed) that doesn't assume I'm a mathematician steeped in the jargon?

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  • Unit testing authorization in a Pylons app fails; cookies aren't been correctly set or recorded

    - by Ian Stevens
    I'm having an issue running unit tests for authorization in a Pylons app. It appears as though certain cookies set in the test case may not be correctly written or parsed. Cookies work fine when hitting the app with a browser. Here is my test case inside a paste-generated TestController: def test_good_login(self): r = self.app.post('/dologin', params={'login': self.user['username'], 'password': self.password}) r = r.follow() # Should only be one redirect to root assert 'http://localhost/' == r.request.url assert 'Dashboard' in r This is supposed to test that a login of an existing account forwards the user to the dashboard page. Instead, what happens is that the user is redirected back to the login. The first POST works, sets the user in the session and returns cookies. Although those cookies are sent in the follow request, they don't seem to be correctly parsed. I start by setting a breakpoint at the beginning of the above method and see what the login response returns: > nosetests --pdb --pdb-failure -s foo.tests.functional.test_account:TestMainController.test_good_login Running setup_config() from foo.websetup > /Users/istevens/dev/foo/foo/tests/functional/test_account.py(33)test_good_login() -> r = self.app.post('/dologin', params={'login': self.user['username'], 'password': self.password}) (Pdb) n > /Users/istevens/dev/foo/foo/tests/functional/test_account.py(34)test_good_login() -> r = r.follow() # Should only be one redirect to root (Pdb) p r.cookies_set {'auth_tkt': '"4c898eb72f7ad38551eb11e1936303374bd871934bd871833d19ad8a79000000!"'} (Pdb) p r.request.environ['REMOTE_USER'] '4bd871833d19ad8a79000000' (Pdb) p r.headers['Location'] 'http://localhost/?__logins=0' A session appears to be created and a cookie sent back. The browser is redirected to the root, not the login, which also indicates a successful login. If I step past the follow(), I get: > /Users/istevens/dev/foo/foo/tests/functional/test_account.py(35)test_good_login() -> assert 'http://localhost/' == r.request.url (Pdb) p r.request.headers {'Host': 'localhost:80', 'Cookie': 'auth_tkt=""\\"4c898eb72f7ad38551eb11e1936303374bd871934bd871833d19ad8a79000000!\\"""; '} (Pdb) p r.request.environ['REMOTE_USER'] *** KeyError: KeyError('REMOTE_USER',) (Pdb) p r.request.environ['HTTP_COOKIE'] 'auth_tkt=""\\"4c898eb72f7ad38551eb11e1936303374bd871934bd871833d19ad8a79000000!\\"""; ' (Pdb) p r.request.cookies {'auth_tkt': ''} (Pdb) p r <302 Found text/html location: http://localhost/login?__logins=1&came_from=http%3A%2F%2Flocalhost%2F body='302 Found...y. '/149> This indicates to me that the cookie was passed in on the request, although with dubious escaping. The environ appears to be without the session created on the prior request. The cookie has been copied to the environ from the headers, but the cookies in the request seems incorrectly set. Lastly, the user is redirected to the login page, indicating that the user isn't logged in. Authorization in the app is done via repoze.who and repoze.who.plugins.ldap with repoze.who_friendlyform performing the challenge. I'm using the stock tests.TestController created by paste: class TestController(TestCase): def __init__(self, *args, **kwargs): if pylons.test.pylonsapp: wsgiapp = pylons.test.pylonsapp else: wsgiapp = loadapp('config:%s' % config['__file__']) self.app = TestApp(wsgiapp) url._push_object(URLGenerator(config['routes.map'], environ)) TestCase.__init__(self, *args, **kwargs) That's a webtest.TestApp, by the way. The encoding of the cookie is done in webtest.TestApp using Cookie: >>> from Cookie import _quote >>> _quote('"84533cf9f661f97239208fb844a09a6d4bd8552d4bd8550c3d19ad8339000000!"') '"\\"84533cf9f661f97239208fb844a09a6d4bd8552d4bd8550c3d19ad8339000000!\\""' I trust that that's correct. My guess is that something on the response side is incorrectly parsing the cookie data into cookies in the server-side request. But what? Any ideas?

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  • Lockless queue implementation ends up having a loop under stress

    - by Fozi
    I have lockless queues written in C in form of a linked list that contains requests from several threads posted to and handled in a single thread. After a few hours of stress I end up having the last request's next pointer pointing to itself, which creates an endless loop and locks up the handling thread. The application runs (and fails) on both Linux and Windows. I'm debugging on Windows, where my COMPARE_EXCHANGE_PTR maps to InterlockedCompareExchangePointer. This is the code that pushes a request to the head of the list, and is called from several threads: void push_request(struct request * volatile * root, struct request * request) { assert(request); do { request->next = *root; } while(COMPARE_EXCHANGE_PTR(root, request, request->next) != request->next); } This is the code that gets a request from the end of the list, and is only called by a single thread that is handling them: struct request * pop_request(struct request * volatile * root) { struct request * volatile * p; struct request * request; do { p = root; while(*p && (*p)->next) p = &(*p)->next; // <- loops here request = *p; } while(COMPARE_EXCHANGE_PTR(p, NULL, request) != request); assert(request->next == NULL); return request; } Note that I'm not using a tail pointer because I wanted to avoid the complication of having to deal with the tail pointer in push_request. However I suspect that the problem might be in the way I find the end of the list. There are several places that push a request into the queue, but they all look generaly like this: // device->requests is defined as struct request * volatile requests; struct request * request = malloc(sizeof(struct request)); if(request) { // fill out request fields push_request(&device->requests, request); sem_post(device->request_sem); } The code that handles the request is doing more than that, but in essence does this in a loop: if(sem_wait_timeout(device->request_sem, timeout) == sem_success) { struct request * request = pop_request(&device->requests); // handle request free(request); } I also just added a function that is checking the list for duplicates before and after each operation, but I'm afraid that this check will change the timing so that I will never encounter the point where it fails. (I'm waiting for it to break as I'm writing this.) When I break the hanging program the handler thread loops in pop_request at the marked position. I have a valid list of one or more requests and the last one's next pointer points to itself. The request queues are usually short, I've never seen more then 10, and only 1 and 3 the two times I could take a look at this failure in the debugger. I thought this through as much as I could and I came to the conclusion that I should never be able to end up with a loop in my list unless I push the same request twice. I'm quite sure that this never happens. I'm also fairly sure (although not completely) that it's not the ABA problem. I know that I might pop more than one request at the same time, but I believe this is irrelevant here, and I've never seen it happening. (I'll fix this as well) I thought long and hard about how I can break my function, but I don't see a way to end up with a loop. So the question is: Can someone see a way how this can break? Can someone prove that this can not? Eventually I will solve this (maybe by using a tail pointer or some other solution - locking would be a problem because the threads that post should not be locked, I do have a RW lock at hand though) but I would like to make sure that changing the list actually solves my problem (as opposed to makes it just less likely because of different timing).

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  • How to generalize a method call in Java (to avoid code duplication)

    - by dln385
    I have a process that needs to call a method and return its value. However, there are several different methods that this process may need to call, depending on the situation. If I could pass the method and its arguments to the process (like in Python), then this would be no problem. However, I don't know of any way to do this in Java. Here's a concrete example. (This example uses Apache ZooKeeper, but you don't need to know anything about ZooKeeper to understand the example.) The ZooKeeper object has several methods that will fail if the network goes down. In this case, I always want to retry the method. To make this easy, I made a "BetterZooKeeper" class that inherits the ZooKeeper class, and all of its methods automatically retry on failure. This is what the code looked like: public class BetterZooKeeper extends ZooKeeper { private void waitForReconnect() { // logic } @Override public Stat exists(String path, Watcher watcher) { while (true) { try { return super.exists(path, watcher); } catch (KeeperException e) { // We will retry. } waitForReconnect(); } } @Override public byte[] getData(String path, boolean watch, Stat stat) { while (true) { try { return super.getData(path, watch, stat); } catch (KeeperException e) { // We will retry. } waitForReconnect(); } } @Override public void delete(String path, int version) { while (true) { try { super.delete(path, version); return; } catch (KeeperException e) { // We will retry. } waitForReconnect(); } } } (In the actual program there is much more logic and many more methods that I took out of the example for simplicity.) We can see that I'm using the same retry logic, but the arguments, method call, and return type are all different for each of the methods. Here's what I did to eliminate the duplication of code: public class BetterZooKeeper extends ZooKeeper { private void waitForReconnect() { // logic } @Override public Stat exists(final String path, final Watcher watcher) { return new RetryableZooKeeperAction<Stat>() { @Override public Stat action() { return BetterZooKeeper.super.exists(path, watcher); } }.run(); } @Override public byte[] getData(final String path, final boolean watch, final Stat stat) { return new RetryableZooKeeperAction<byte[]>() { @Override public byte[] action() { return BetterZooKeeper.super.getData(path, watch, stat); } }.run(); } @Override public void delete(final String path, final int version) { new RetryableZooKeeperAction<Object>() { @Override public Object action() { BetterZooKeeper.super.delete(path, version); return null; } }.run(); return; } private abstract class RetryableZooKeeperAction<T> { public abstract T action(); public final T run() { while (true) { try { return action(); } catch (KeeperException e) { // We will retry. } waitForReconnect(); } } } } The RetryableZooKeeperAction is parameterized with the return type of the function. The run() method holds the retry logic, and the action() method is a placeholder for whichever ZooKeeper method needs to be run. Each of the public methods of BetterZooKeeper instantiates an anonymous inner class that is a subclass of the RetryableZooKeeperAction inner class, and it overrides the action() method. The local variables are (strangely enough) implicitly passed to the action() method, which is possible because they are final. In the end, this approach does work and it does eliminate the duplication of the retry logic. However, it has two major drawbacks: (1) it creates a new object every time a method is called, and (2) it's ugly and hardly readable. Also I had to workaround the 'delete' method which has a void return value. So, here is my question: is there a better way to do this in Java? This can't be a totally uncommon task, and other languages (like Python) make it easier by allowing methods to be passed. I suspect there might be a way to do this through reflection, but I haven't been able to wrap my head around it.

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  • "didChangeSection:" NSfetchedResultsController delegate method not being called

    - by robenk
    I have a standard split view controller, with a detail view and a table view. Pressing a button in the detail view can cause the an object to change its placement in the table view's ordering. This works fine, as long as the resulting ordering change doesn't result in a section being added or removed. I.e. an object can change it's ordering in a section or switch from one section to another. Those ordering changes work correctly without problems. But, if the object tries to move to a section that doesn't exist yet, or is the last object to leave a section (therefore requiring the section its leaving to be removed), then the application crashes. NSFetchedResultsControllerDelegate has methods to handle sections being added and removed that should be called in those cases. But those delegate methods aren't being called for some reason. The code in question, is boilerplate: - (void)controllerWillChangeContent:(NSFetchedResultsController *)controller { NSLog(@"willChangeContent"); [self.tableView beginUpdates]; } - (void)controller:(NSFetchedResultsController *)controller didChangeSection:(id <NSFetchedResultsSectionInfo>)sectionInfo atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type { NSLog(@"didChangeSection"); switch(type) { case NSFetchedResultsChangeInsert: [self.tableView insertSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade]; break; case NSFetchedResultsChangeDelete: [self.tableView deleteSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade]; break; } } - (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type newIndexPath:(NSIndexPath *)newIndexPath { NSLog(@"didChangeObject"); UITableView *tableView = self.tableView; switch(type) { case NSFetchedResultsChangeInsert: [tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationFade]; break; case NSFetchedResultsChangeDelete: [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade]; break; case NSFetchedResultsChangeUpdate: [self configureCell:[tableView cellForRowAtIndexPath:indexPath] atIndexPath:indexPath]; break; case NSFetchedResultsChangeMove: [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade]; [tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath]withRowAnimation:UITableViewRowAnimationFade]; break; } } - (void)controllerDidChangeContent:(NSFetchedResultsController *)controller { NSLog(@"didChangeContent"); [self.tableView endUpdates]; [detailViewController.reminderView update]; } Starting the application, and then causing the last object to leave a section results in the following output: 2011-01-08 23:40:18.910 Reminders[54647:207] willChangeContent 2011-01-08 23:40:18.912 Reminders[54647:207] didChangeObject 2011-01-08 23:40:18.914 Reminders[54647:207] didChangeContent 2011-01-08 23:40:18.915 Reminders[54647:207] *** Assertion failure in -[UITableView _endCellAnimationsWithContext:], /SourceCache/UIKit_Sim/UIKit-1145.66/UITableView.m:825 2011-01-08 23:40:18.917 Reminders[54647:207] Serious application error. Exception was caught during Core Data change processing: Invalid update: invalid number of sections. The number of sections contained in the table view after the update (5) must be equal to the number of sections contained in the table view before the update (6), plus or minus the number of sections inserted or deleted (0 inserted, 0 deleted). with userInfo (null) As you can see, "willChangeContent", "didChangeObject" (moving the object in question), and "didChangeContent" were all called properly. Based on the Apple's NSFetchedResultsControllerDelegate documentation "didChangeSection" should have been called before "didChangeObject", which would have prevented the exception causing the crash. So I guess the question is how do I assure that didChangeSection gets called? Thanks in advance for any help!

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  • What broke in this Javascript 1.2 snippet?

    - by Rob Kelley
    A friend has pointed me to his old website and says "the submit form just stopped working a while ago. I'm sure it's something simple." The form asks a child for a certain word from a book, and based on the answer, it should redirect the child to a success page or a failure page. It's using Javascript 1.2, circa 2001. You can see this form in in-action at: http://www.secrethidingplaces.com/login1.html Any idea why it's failing? The HTML does this: <script src="password.js" type="text/javascript" language="JavaScript1.2"> </script> <script type="text/javascript" language="JavaScript1.2"> <!-- function showRightPage () { return window.location.href = "extra.html" ; } function showWrongPage () { return window.location.href = "sorry2.html" ; } //--> </script> and then this: document.write ( '<form name="questionForm" action="javascript:checkAnswer()" method="post">' ) ; ... document.write ( '<input type="text" name="userAnswer" value="" size="90">' ) ; document.write ( '<INPUT TYPE="image" NAME="submit" SRC="stock/btn_send.gif" width="121" height="41" BORDER="0" ALT="submit">' ) ; document.write ( '\</p>' ) ; document.write ( '\</form>' ) ; I'm assuming there's something ugly in CheckAnswer from ./password.js . I can hack the form to bypass that javascript and go straight to the success page: document.write ( '<form name="questionForm" action="extra.html" method="post">' ) ; but I'd like to help my friend get his kids site working again. The CheckAnswer function is below. Is something going wrong in here? function checkAnswer () { currentAnswer = answersArray [ choiceNumber ] ; if (agt.indexOf("msie") != -1) { rawAnswer = document.questionForm.userAnswer.value ; } else { rawAnswer = document.callThis.document.questionForm.userAnswer.value ; } lcAnswer = rawAnswer.toLowerCase ( ) ; includedAnswer = lcAnswer.indexOf ( "currentAnswer" ) ; zadaAnswer = lcAnswer.indexOf ( "zada" ) ; brendanAnswer = lcAnswer.indexOf ( "brendan" ) ; nineAnswer = lcAnswer.indexOf ( "nine" ) ; thirtyAnswer = lcAnswer.indexOf ( "thirty" ) ; if ( choiceNumber == 0 ) { if ( includedAnswer == -1 && zadaAnswer == -1 && brendanAnswer == -1 ) { checked = "wrong" ; } } if ( choiceNumber == 8 ) { if ( includedAnswer == -1 && zadaAnswer == -1 && nineAnswer == -1 ) { checked = "wrong" ; } } if ( choiceNumber == 16 ) { if ( includedAnswer == -1 && zadaAnswer == -1 && thirtyAnswer == -1 ) { checked = "wrong" ; } } if ( choiceNumber != 0 && choiceNumber != 8 && choiceNumber != 16 ) { if ( includedAnswer == -1 && zadaAnswer == -1 ) { checked = "wrong" ; } } if ( checked == "wrong" ) { showWrongPage () ; } else { showRightPage () ; } } Thanks!

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  • xmlpullparser(), whats wrong with my code?

    - by Avinazz
    I am expecting output to be an array list filled with all items as "thought" but instead, every time i add a value into arraylist, the previous value in list also gets update with new, hence resulting in duplicates. This behaviour goes on till end. Even though i have achieved the result by changing the approach, failure of my previous approach still bothers me. Any help or pointer will be really appreciated. Below is xml snippet: <Thoughts> <country> <name>India</name> <item> <itemId>1</itemId> <itemDetailImage>detail.png</itemDetailImage> <itemImage>image1.png</itemImage> <itemDesc>Item Description 1</itemDesc> <itemTitle>Item Title 1</itemTitle> </item> <item> <itemId>2</itemId> <itemDetailImage>detail2.png</itemDetailImage> <itemImage>image2.png</itemImage> <itemDesc>Item Description 2</itemDesc> <itemTitle>Item Title 2</itemTitle> </item> <item> <itemId>3</itemId> <itemDetailImage>detail3.png</itemDetailImage> <itemImage>image3.png</itemImage> <itemDesc>Item Description 3</itemDesc> <itemTitle>Item Title 3</itemTitle> </item> Below is a method for my trial and error: private void printAll() throws XmlPullParserException, IOException{ XmlPullParserFactory factory = XmlPullParserFactory.newInstance(); factory.setNamespaceAware(false); XmlPullParser parser = factory.newPullParser(); URL url = new URL("http://192.168.1.3/DefaultXML.xml"); URLConnection ucon = url.openConnection(); InputStream is = ucon.getInputStream(); parser.setInput(is, null); int eventType = parser.getEventType(); String name; while(eventType != parser.END_DOCUMENT){ if(eventType == parser.START_DOCUMENT){ Log.i(TAG,"Start document"); }else if (eventType == parser.START_TAG ) { name = parser.getName(); if(name.equalsIgnoreCase(NAME)){ this.cName = new Country(); this.cName.setName(parser.nextText()); }else if(name.equalsIgnoreCase(ITEM_DESC)){ this.thought.setItemDesc(parser.nextText()); }else if (name.equalsIgnoreCase(ITEM_ID)) { this.thought.setItemID(parser.nextText()); }else if (name.equalsIgnoreCase(ITEM_DETAIL_IMAGE)) { this.thought.setItemDetailImage(parser.nextText()); }else if (name.equalsIgnoreCase(ITEM_IMAGE)) { this.thought.setItemImage(parser.nextText()); }else if (name.equalsIgnoreCase(ITEM_TITLE)) { this.thought.setItemTitle(parser.nextText()); } }else if (eventType == parser.END_TAG) { name = parser.getName(); if(name.equalsIgnoreCase(ITEM)) { this.cName.setThought(this.thought); ctry.add(cName); this.thought = new Thought(); } } eventType = parser.next(); } //Log.i(TAG,"---" + ctry.toString()); }

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  • OpenGL texture misaligned on quad

    - by user308226
    I've been having trouble with this for a while now, and I haven't gotten any solutions that work yet. Here is the problem, and the specifics: I am loading a 256x256 uncompressed TGA into a simple OpenGL program that draws a quad on the screen, but when it shows up, it is shifted about two pixels to the left, with the cropped part appearing on the right side. It has been baffling me for the longest time, people have suggested clamping and such, but somehow I think my problem is probably something really simple, but I just can't figure out what it is! Here is a screenshot comparing the TGA (left) and how it appears running in the program (right) for clarity. Also take note that there's a tiny black pixel on the upper right corner, I'm hoping that's related to the same problem. Here's the code for the loader, I'm convinced that my problem lies in the way that I'm loading the texture. Thanks in advance to anyone who can fix my problem. bool TGA::LoadUncompressedTGA(char *filename,ifstream &texturestream) { cout << "G position status:" << texturestream.tellg() << endl; texturestream.read((char*)header, sizeof(header)); //read 6 bytes into the file to get the tga header width = (GLuint)header[1] * 256 + (GLuint)header[0]; //read and calculate width and save height = (GLuint)header[3] * 256 + (GLuint)header[2]; //read and calculate height and save bpp = (GLuint)header[4]; //read bpp and save cout << bpp << endl; if((width <= 0) || (height <= 0) || ((bpp != 24) && (bpp !=32))) //check to make sure the height, width, and bpp are valid { return false; } if(bpp == 24) { type = GL_RGB; } else { type = GL_RGBA; } imagesize = ((bpp/8) * width * height); //determine size in bytes of the image cout << imagesize << endl; imagedata = new GLubyte[imagesize]; //allocate memory for our imagedata variable texturestream.read((char*)imagedata,imagesize); //read according the the size of the image and save into imagedata for(GLuint cswap = 0; cswap < (GLuint)imagesize; cswap += (bpp/8)) //loop through and reverse the tga's BGR format to RGB { imagedata[cswap] ^= imagedata[cswap+2] ^= //1st Byte XOR 3rd Byte XOR 1st Byte XOR 3rd Byte imagedata[cswap] ^= imagedata[cswap+2]; } texturestream.close(); //close ifstream because we're done with it cout << "image loaded" << endl; glGenTextures(1, &texID); // Generate OpenGL texture IDs glBindTexture(GL_TEXTURE_2D, texID); glPixelStorei(GL_UNPACK_ALIGNMENT, 1); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); glTexImage2D(GL_TEXTURE_2D, 0, type, width, height, 0, type, GL_UNSIGNED_BYTE, imagedata); delete imagedata; return true; } //Public loading function for TGA images. Opens TGA file and determines //its type, if any, then loads it and calls the appropriate function. //Returns: TRUE on success, FALSE on failure bool TGA::loadTGA(char *filename) { cout << width << endl; ifstream texturestream; texturestream.open(filename,ios::binary); texturestream.read((char*)header,sizeof(header)); //read 6 bytes into the file, its the header. //if it matches the uncompressed header's first 6 bytes, load it as uncompressed LoadUncompressedTGA(filename,texturestream); return true; }

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  • How can I keep my MVC Views, models, and model binders as clean as possible?

    - by MBonig
    I'm rather new to MVC and as I'm getting into the whole framework more and more I'm finding the modelbinders are becoming tough to maintain. Let me explain... I am writing a basic CRUD-over-database app. My domain models are going to be very rich. In an attempt to keep my controllers as thin as possible I've set it up so that on Create/Edit commands the parameter for the action is a richly populated instance of my domain model. To do this I've implemented a custom model binder. As a result, though, this custom model binder is very specific to the view and the model. I've decided to just override the DefaultModelBinder that ships with MVC 2. In the case where the field being bound to my model is just a textbox (or something as simple), I just delegate to the base method. However, when I'm working with a dropdown or something more complex (the UI dictates that date and time are separate data entry fields but for the model it is one Property), I have to perform some checks and some manual data munging. The end result of this is that I have some pretty tight ties between the View and Binder. I'm architecturally fine with this but from a code maintenance standpoint, it's a nightmare. For example, my model I'm binding here is of type Log (this is the object I will get as a parameter on my Action). The "ServiceStateTime" is a property on Log. The form values of "log.ServiceStartDate" and "log.ServiceStartTime" are totally arbitrary and come from two textboxes on the form (Html.TextBox("log.ServiceStartTime",...)) protected override object GetPropertyValue(ControllerContext controllerContext, ModelBindingContext bindingContext, PropertyDescriptor propertyDescriptor, IModelBinder propertyBinder) { if (propertyDescriptor.Name == "ServiceStartTime") { string date = bindingContext.ValueProvider.GetValue("log.ServiceStartDate").ConvertTo(typeof (string)) as string; string time = bindingContext.ValueProvider.GetValue("log.ServiceStartTime").ConvertTo(typeof (string)) as string; DateTime dateTime = DateTime.Parse(date + " " + time); return dateTime; } if (propertyDescriptor.Name == "ServiceEndTime") { string date = bindingContext.ValueProvider.GetValue("log.ServiceEndDate").ConvertTo(typeof(string)) as string; string time = bindingContext.ValueProvider.GetValue("log.ServiceEndTime").ConvertTo(typeof(string)) as string; DateTime dateTime = DateTime.Parse(date + " " + time); return dateTime; } The Log.ServiceEndTime is a similar field. This doesn't feel very DRY to me. First, if I refactor the ServiceStartTime or ServiceEndTime into different field names, the text strings may get missed (although my refactoring tool of choice, R#, is pretty good at this sort of thing, it wouldn't cause a build-time failure and would only get caught by manual testing). Second, if I decided to arbitrarily change the descriptors "log.ServiceStartDate" and "log.ServiceStartTime", I would run into the same problem. To me, runtime silent errors are the worst kind of error out there. So, I see a couple of options to help here and would love to get some input from people who have come across some of these issues: Refactor any text strings in common between the view and model binders out into const strings attached to the ViewModel object I pass from controller to the aspx/ascx view. This pollutes the ViewModel object, though. Provide unit tests around all of the interactions. I'm a big proponent of unit tests and haven't started fleshing this option out but I've got a gut feeling that it won't save me from foot-shootings. If it matters, the Log and other entities in the system are persisted to the database using Fluent NHibernate. I really want to keep my controllers as thin as possible. So, any suggestions here are greatly welcomed! Thanks

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  • Templated function with two type parameters fails compile when used with an error-checking macro

    - by SirPentor
    Because someone in our group hates exceptions (let's not discuss that here), we tend to use error-checking macros in our C++ projects. I have encountered an odd compilation failure when using a templated function with two type parameters. There are a few errors (below), but I think the root cause is a warning: warning C4002: too many actual parameters for macro 'BOOL_CHECK_BOOL_RETURN' Probably best explained in code: #include "stdafx.h" template<class A, class B> bool DoubleTemplated(B & value) { return true; } template<class A> bool SingleTemplated(A & value) { return true; } bool NotTemplated(bool & value) { return true; } #define BOOL_CHECK_BOOL_RETURN(expr) \ do \ { \ bool __b = (expr); \ if (!__b) \ { \ return false; \ } \ } while (false) \ bool call() { bool thing = true; // BOOL_CHECK_BOOL_RETURN(DoubleTemplated<int, bool>(thing)); // Above line doesn't compile. BOOL_CHECK_BOOL_RETURN((DoubleTemplated<int, bool>(thing))); // Above line compiles just fine. bool temp = DoubleTemplated<int, bool>(thing); // Above line compiles just fine. BOOL_CHECK_BOOL_RETURN(SingleTemplated<bool>(thing)); BOOL_CHECK_BOOL_RETURN(NotTemplated(thing)); return true; } int _tmain(int argc, _TCHAR* argv[]) { call(); return 0; } Here are the errors, when the offending line is not commented out: 1>------ Build started: Project: test, Configuration: Debug Win32 ------ 1>Compiling... 1>test.cpp 1>c:\junk\temp\test\test\test.cpp(38) : warning C4002: too many actual parameters for macro 'BOOL_CHECK_BOOL_RETURN' 1>c:\junk\temp\test\test\test.cpp(38) : error C2143: syntax error : missing ',' before ')' 1>c:\junk\temp\test\test\test.cpp(38) : error C2143: syntax error : missing ';' before '{' 1>c:\junk\temp\test\test\test.cpp(41) : error C2143: syntax error : missing ';' before '{' 1>c:\junk\temp\test\test\test.cpp(48) : error C2143: syntax error : missing ';' before '{' 1>c:\junk\temp\test\test\test.cpp(49) : error C2143: syntax error : missing ';' before '{' 1>c:\junk\temp\test\test\test.cpp(52) : error C2143: syntax error : missing ';' before '}' 1>c:\junk\temp\test\test\test.cpp(54) : error C2065: 'argv' : undeclared identifier 1>c:\junk\temp\test\test\test.cpp(54) : error C2059: syntax error : ']' 1>c:\junk\temp\test\test\test.cpp(55) : error C2143: syntax error : missing ';' before '{' 1>c:\junk\temp\test\test\test.cpp(58) : error C2143: syntax error : missing ';' before '}' 1>c:\junk\temp\test\test\test.cpp(60) : error C2143: syntax error : missing ';' before '}' 1>c:\junk\temp\test\test\test.cpp(60) : fatal error C1004: unexpected end-of-file found 1>Build log was saved at "file://c:\junk\temp\test\test\Debug\BuildLog.htm" 1>test - 12 error(s), 1 warning(s) ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ========== Any ideas? Thanks!

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  • PHP Form - Empty input enter this text - Validation

    - by James Skelton
    No doubt very simple question for someone with php knowledge. I have a form with a datepicker, all is fine when a user has selected a date the email is send with: Date: 2012 04 10 But i would like if the user has skipped this and left blank (as i have not made this required) to send as: Date: Not Entered (<-- Or something) Instead at the minute of course it reads: Date: Form input <input type="text" class="form-control" id="datepicker" name="datepicker" size="50" value="Date Of Wedding" /> This is the validator $(document).ready(function(){ //validation contact form $('#submit').click(function(event){ event.preventDefault(); var fname = $('#name').val(); var validInput = new RegExp(/^[a-zA-Z0-9\s]+$/); var email = $('#email').val(); var validEmail = new RegExp(/^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/); var message = $('#message').val(); if(fname==''){ showError('<div class="alert alert-danger">Please enter your name.</div>', $('#name')); $('#name').addClass('required'); return;} if(!validInput.test(fname)){ showError('<div class="alert alert-danger">Please enter a valid name.</div>', $('#name')); $('#name').addClass('required'); return;} if(email==''){ showError('<div class="alert alert-danger">Please enter an email address.</div>', $('#email')); $('#email').addClass('required'); return;} if(!validEmail.test(email)){ showError('<div class="alert alert-danger">Please enter a valid email.</div>', $('#email')); $('#email').addClass('required'); return;} if(message==''){ showError('<div class="alert alert-danger">Please enter a message.</div>', $('#message')); $('#message').addClass('required'); return;} // setup some local variables var request; var form = $(this).closest('form'); // serialize the data in the form var serializedData = form.serialize(); // fire off the request to /contact.php request = $.ajax({ url: "contact.php", type: "post", data: serializedData }); // callback handler that will be called on success request.done(function (response, textStatus, jqXHR){ $('.contactWrap').show( 'slow' ).fadeIn("slow").html(' <div class="alert alert-success centered"><h3>Thank you! Your message has been sent.</h3></div> '); }); // callback handler that will be called on failure request.fail(function (jqXHR, textStatus, errorThrown){ // log the error to the console console.error( "The following error occured: "+ textStatus, errorThrown ); }); }); //remove 'required' class and hide error $('input, textarea').keyup( function(event){ if($(this).hasClass('required')){ $(this).removeClass('required'); $('.error').hide("slow").fadeOut("slow"); } }); // show error showError = function (error, target){ $('.error').removeClass('hidden').show("slow").fadeIn("slow").html(error); $('.error').data('target', target); $(target).focus(); console.log(target); console.log(error); return; } });

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  • How can i clear a SQLite database each time i start my app

    - by AndroidUser99
    Hi, i want that each time i start my app my SQLite database get's cleaned for this, i need to make a method on my class MyDBAdapter.java code examples are welcome, i have no idea how to do it this is the dbadapter/helper i'm using: public class MyDbAdapter { private static final String TAG = "NotesDbAdapter"; private DatabaseHelper mDbHelper; private SQLiteDatabase mDb; private static final String DATABASE_NAME = "gpslocdb"; private static final String PERMISSION_TABLE_CREATE = "CREATE TABLE permission ( fk_email1 varchar, fk_email2 varchar, validated tinyint, hour1 time default '08:00:00', hour2 time default '20:00:00', date1 date, date2 date, weekend tinyint default '0', fk_type varchar, PRIMARY KEY (fk_email1,fk_email2))"; private static final String USER_TABLE_CREATE = "CREATE TABLE user ( email varchar, password varchar, fullName varchar, mobilePhone varchar, mobileOperatingSystem varchar, PRIMARY KEY (email))"; private static final int DATABASE_VERSION = 2; private final Context mCtx; private static class DatabaseHelper extends SQLiteOpenHelper { DatabaseHelper(Context context) { super(context, DATABASE_NAME, null, DATABASE_VERSION); } @Override public void onCreate(SQLiteDatabase db) { db.execSQL(PERMISSION_TABLE_CREATE); db.execSQL(USER_TABLE_CREATE); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { db.execSQL("DROP TABLE IF EXISTS user"); db.execSQL("DROP TABLE IF EXISTS permission"); onCreate(db); } } /** * Constructor - takes the context to allow the database to be * opened/created * * @param ctx the Context within which to work */ public MyDbAdapter(Context ctx) { this.mCtx = ctx; } /** * Open the database. If it cannot be opened, try to create a new * instance of the database. If it cannot be created, throw an exception to * signal the failure * * @return this (self reference, allowing this to be chained in an * initialization call) * @throws SQLException if the database could be neither opened or created */ public MyDbAdapter open() throws SQLException { mDbHelper = new DatabaseHelper(mCtx); mDb = mDbHelper.getWritableDatabase(); return this; } public void close() { mDbHelper.close(); } public long createUser(String email, String password, String fullName, String mobilePhone, String mobileOperatingSystem) { ContentValues initialValues = new ContentValues(); initialValues.put("email",email); initialValues.put("password",password); initialValues.put("fullName",fullName); initialValues.put("mobilePhone",mobilePhone); initialValues.put("mobileOperatingSystem",mobileOperatingSystem); return mDb.insert("user", null, initialValues); } public Cursor fetchAllUsers() { return mDb.query("user", new String[] {"email", "password", "fullName", "mobilePhone", "mobileOperatingSystem"}, null, null, null, null, null); } public Cursor fetchUser(String email) throws SQLException { Cursor mCursor = mDb.query(true, "user", new String[] {"email", "password", "fullName", "mobilePhone", "mobileOperatingSystem"} , "email" + "=" + email, null, null, null, null, null); if (mCursor != null) { mCursor.moveToFirst(); } return mCursor; } public List<Friend> retrieveAllUsers() { List <Friend> friends=new ArrayList<Friend>(); Cursor result=fetchAllUsers(); if( result.moveToFirst() ){ do{ //note.getString(note.getColumnIndexOrThrow(NotesDbAdapter.KEY_TITLE))); friends.add(new Friend(result.getString(result.getColumnIndexOrThrow("email")), "","","","")); }while( result.moveToNext() ); } return friends; } }

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  • Can't save my picture

    - by mamii
    I want to save the image that I draw, but I always failure is reported. I have tested and tried but I can correct any errors. Therefore, I appeal to you. This store is for me as a "cancer sore". And what is the drawing application without the possibility shranjevnja? sucks: D Question: What is wrong with my code for storage? or anything else? Posts: 09-12 07:30:34.346: E / Panel (8003): IOEception 09-12 07:30:34.346: E / Panel (8003): java.io.IOException: Parent directory of file does not exist: / sdcard/anppp/2012Sep1273034.png 09-12 07:30:34.346: E / Panel (8003): at java.io.File.createNewFile (File.java: 1263) 09-12 07:30:34.346: E / Panel (8003): at aa.bb.cc.Panel.saveapp (Panel.java: 67) 09-12 07:30:34.346: E / Panel (8003): at aa.bb.cc.AndroidPaint.onOptionsItemSelected (AndroidPaint.java: 94) 09-12 07:30:34.346: E / Panel (8003): at android.app.Activity.onMenuItemSelected (Activity.java: 2170) 09-12 07:30:34.346: E / Panel (8003): at com.android.internal.policy.impl.PhoneWindow.onMenuItemSelected (PhoneWindow.java: 730) 09-12 07:30:34.346: E / Panel (8003): at com.android.internal.view.menu.MenuItemImpl.invoke (MenuItemImpl.java: 139) 09-12 07:30:34.346: E / Panel (8003): at com.android.internal.view.menu.MenuBuilder.performItemAction (MenuBuilder.java: 855) 09-12 07:30:34.346: E / Panel (8003): at com.android.internal.view.menu.ExpandedMenuView.invokeItem (ExpandedMenuView.java: 89) 09-12 07:30:34.346: E / Panel (8003): at com.android.internal.view.menu.ExpandedMenuView.onItemClick (ExpandedMenuView.java: 93) 09-12 07:30:34.346: E / Panel (8003): at android.widget.AdapterView.performItemClick (AdapterView.java: 284) 09-12 07:30:34.346: E / Panel (8003): at android.widget.ListView.performItemClick (ListView.java: 3285) 09-12 07:30:34.346: E / Panel (8003): at android.widget.AbsListView $ PerformClick.run (AbsListView.java: 1640) 09-12 07:30:34.346: E / Panel (8003): at android.os.Handler.handleCallback (Handler.java: 587) 09-12 07:30:34.346: E / Panel (8003): at android.os.Handler.dispatchMessage (Handler.java: 92) 09-12 07:30:34.346: E / Panel (8003): at android.os.Looper.loop (Looper.java: 123) 09-12 07:30:34.346: E / Panel (8003): at android.app.ActivityThread.main (ActivityThread.java: 4363) 09-12 07:30:34.346: E / Panel (8003): at java.lang.reflect.Method.invokeNative (Native Method) 09-12 07:30:34.346: E / Panel (8003): at java.lang.reflect.Method.invoke (Method.java: 521) 09-12 07:30:34.346: E / Panel (8003): at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run (ZygoteInit.java: 860) 09-12 07:30:34.346: E / Panel (8003): at com.android.internal.os.ZygoteInit.main (ZygoteInit.java: 618) 09-12 07:30:34.346: E / Panel (8003): at dalvik.system.NativeStart.main (Native Method) There is code: private Bitmap mBitmap; private Canvas mCanvas; private Bitmap tmpBitmap; private Canvas tmpCanvas; private DrawHandler mDrawHandler; private Canvas tCanvas; private String mImagePath = Environment.getExternalStorageDirectory() + "/anppp"; private File file; public void saveapp() { Calendar currentDate = Calendar.getInstance(); SimpleDateFormat formatter= new SimpleDateFormat("yyyyMMMddHmmss"); String dateNow = formatter.format(currentDate.getTime()); file = new File(mImagePath + "/" + dateNow +".png"); FileOutputStream fos; try { file.createNewFile(); fos = new FileOutputStream(file); tmpBitmap.compress(Bitmap.CompressFormat.PNG, 100, fos); fos.close(); } catch (FileNotFoundException e) { Log.e("Panel", "FileNotFoundException", e); } catch (IOException e) { Log.e("Panel", "IOEception", e); } } That's it .. I do not know what could be wrong ;(

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  • Installing Lubuntu 14.04.1 fails, upowerd appears to hang

    - by Rantanplan
    On the live-CD session, I tried installing Lubuntu double clicking on the install button on the desktop. Here, the CD starts running but then stops running and nothing happens. Next, I rebooted and tried installing Lubuntu directly from the boot menu screen using forcepae again. After a while, I receive the following error message: The installer encountered an unrecoverable error. A desktop session will now be run so that you may investigate the problem or try installing again. Hitting Enter brings me to the desktop. For what errors should I search? And how? Thanks for some hints! On Lubuntu 12.04: uname -a Linux humboldt 3.2.0-67-generic #101-Ubuntu SMP Tue Jul 15 17:45:51 UTC 2014 i686 i686 i386 GNU/Linux lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 12.04.5 LTS Release: 12.04 Codename: precise upowerd appears to hang: Aug 25 10:53:28 lubuntu kernel: [ 367.920272] INFO: task upowerd:3002 blocked for more than 120 seconds. Aug 25 10:53:28 lubuntu kernel: [ 367.920288] Tainted: G S C 3.13.0-32-generic #57-Ubuntu Aug 25 10:53:28 lubuntu kernel: [ 367.920294] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Aug 25 10:53:28 lubuntu kernel: [ 367.920300] upowerd D e21f9da0 0 3002 1 0x00000000 Aug 25 10:53:28 lubuntu kernel: [ 367.920314] e21f9dfc 00000086 f5ef7094 e21f9da0 c1050272 c1a8d540 c1920a00 00000000 Aug 25 10:53:28 lubuntu kernel: [ 367.920333] c1a8d540 c1920a00 d9e44da0 f5ef6540 c1129061 00000002 000001c1 0001c37b Aug 25 10:53:28 lubuntu kernel: [ 367.920351] 00000000 00000002 00000000 e2276240 00000000 00000040 c12b0ec5 c19975a8 Aug 25 10:53:28 lubuntu kernel: [ 367.920368] Call Trace: Aug 25 10:53:28 lubuntu kernel: [ 367.920389] [<c1050272>] ? kmap_atomic_prot+0x42/0x100 Aug 25 10:53:28 lubuntu kernel: [ 367.920404] [<c1129061>] ? get_page_from_freelist+0x2a1/0x600 Aug 25 10:53:28 lubuntu kernel: [ 367.920417] [<c12b0ec5>] ? process_measurement+0x65/0x240 Aug 25 10:53:28 lubuntu kernel: [ 367.920432] [<c1654c73>] schedule_preempt_disabled+0x23/0x60 Aug 25 10:53:28 lubuntu kernel: [ 367.920443] [<c16565bd>] __mutex_lock_slowpath+0x10d/0x171 Aug 25 10:53:28 lubuntu kernel: [ 367.920454] [<c1655aec>] mutex_lock+0x1c/0x28 Aug 25 10:53:28 lubuntu kernel: [ 367.920478] [<f857223a>] acpi_smbus_transaction+0x48/0x210 [sbshc] Aug 25 10:53:28 lubuntu kernel: [ 367.920489] [<c11858e1>] ? do_last+0x1b1/0xf60 Aug 25 10:53:28 lubuntu kernel: [ 367.920504] [<f857242f>] acpi_smbus_read+0x2d/0x33 [sbshc] Aug 25 10:53:28 lubuntu kernel: [ 367.920520] [<f881e0f1>] acpi_battery_get_state+0x74/0x8b [sbs] Aug 25 10:53:28 lubuntu kernel: [ 367.920535] [<f881e8a9>] acpi_sbs_battery_get_property+0x2a/0x233 [sbs] Aug 25 10:53:28 lubuntu kernel: [ 367.920549] [<c14fa61f>] power_supply_show_property+0x3f/0x240 Aug 25 10:53:28 lubuntu kernel: [ 367.920561] [<c114664f>] ? handle_mm_fault+0x64f/0x8d0 Aug 25 10:53:28 lubuntu kernel: [ 367.920573] [<c14fa5e0>] ? power_supply_store_property+0x60/0x60 Aug 25 10:53:28 lubuntu kernel: [ 367.920586] [<c1407d20>] ? dev_uevent_name+0x30/0x30 Aug 25 10:53:28 lubuntu kernel: [ 367.920597] [<c1407d38>] dev_attr_show+0x18/0x40 Aug 25 10:53:28 lubuntu kernel: [ 367.920608] [<c11dad15>] sysfs_seq_show+0xe5/0x1c0 Aug 25 10:53:28 lubuntu kernel: [ 367.920621] [<c119846e>] seq_read+0xce/0x370 Aug 25 10:53:28 lubuntu kernel: [ 367.920633] [<c11983a0>] ? seq_hlist_next_percpu+0x90/0x90 Aug 25 10:53:28 lubuntu kernel: [ 367.920644] [<c1179238>] vfs_read+0x78/0x140 Aug 25 10:53:28 lubuntu kernel: [ 367.920654] [<c11799a9>] SyS_read+0x49/0x90 Aug 25 10:53:28 lubuntu kernel: [ 367.920667] [<c165efcd>] sysenter_do_call+0x12/0x28 /var/log/installer/debug shows upower related error: Ubiquity 2.18.8 Gtk-Message: Failed to load module "overlay-scrollbar" Gtk-Message: Failed to load module "overlay-scrollbar" ERROR:dbus.proxies:Introspect error on :1.23:/org/freedesktop/UPower: dbus.exceptions.DBusException: org.freedesktop.DBus.Error.NoReply: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken. Exception in GTK frontend (invoking crash handler): Traceback (most recent call last): File "/usr/lib/ubiquity/bin/ubiquity", line 636, in <module> main(oem_config) File "/usr/lib/ubiquity/bin/ubiquity", line 622, in main install(query=options.query) File "/usr/lib/ubiquity/bin/ubiquity", line 260, in install wizard = ui.Wizard(distro) File "/usr/lib/ubiquity/ubiquity/frontend/gtk_ui.py", line 290, in __init__ mod.ui = mod.ui_class(mod.controller) File "/usr/lib/ubiquity/plugins/ubi-prepare.py", line 93, in __init__ upower.setup_power_watch(self.prepare_power_source) File "/usr/lib/ubiquity/ubiquity/upower.py", line 21, in setup_power_watch power_state_changed() File "/usr/lib/ubiquity/ubiquity/upower.py", line 18, in power_state_changed not misc.get_prop(upower, UPOWER_PATH, 'OnBattery')) File "/usr/lib/ubiquity/ubiquity/misc.py", line 809, in get_prop return obj.Get(iface, prop, dbus_interface=dbus.PROPERTIES_IFACE) File "/usr/lib/python3/dist-packages/dbus/proxies.py", line 70, in __call__ return self._proxy_method(*args, **keywords) File "/usr/lib/python3/dist-packages/dbus/proxies.py", line 145, in __call__ **keywords) File "/usr/lib/python3/dist-packages/dbus/connection.py", line 651, in call_blocking message, timeout)

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  • Complete Guide to Networking Windows 7 with XP and Vista

    - by Mysticgeek
    Since there are three versions of Windows out in the field these days, chances are you need to share data between them. Today we show how to get each version to be share files and printers with one another. In a perfect world, getting your computers with different Microsoft operating systems to network would be as easy as clicking a button. With the Windows 7 Homegroup feature, it’s almost that easy. However, getting all three of them to communicate with each other can be a bit of a challenge. Today we’ve put together a guide that will help you share files and printers in whatever scenario of the three versions you might encounter on your home network. Sharing Between Windows 7 and XP The most common scenario you’re probably going to run into is sharing between Windows 7 and XP.  Essentially you’ll want to make sure both machines are part of the same workgroup, set up the correct sharing settings, and making sure network discovery is enabled on Windows 7. The biggest problem you may run into is finding the correct printer drivers for both versions of Windows. Share Files and Printers Between Windows 7 & XP  Map a Network Drive Another method of sharing data between XP and Windows 7 is mapping a network drive. If you don’t need to share a printer and only want to share a drive, then you can just map an XP drive to Windows 7. Although it might sound complicated, the process is not bad. The trickiest part is making sure you add the appropriate local user. This will allow you to share the contents of an XP drive to your Windows 7 computer. Map a Network Drive from XP to Windows 7 Sharing between Vista and Windows 7 Another scenario you might run into is having to share files and printers between a Vista and Windows 7 machine. The process is a bit easier than sharing between XP and Windows 7, but takes a bit of work. The Homegroup feature isn’t compatible with Vista, so we need to go through a few different steps. Depending on what your printer is, sharing it should be easier as Vista and Windows 7 do a much better job of automatically locating the drivers. How to Share Files and Printers Between Windows 7 and Vista Sharing between Vista and XP When Windows Vista came out, hardware requirements were intensive, drivers weren’t ready, and sharing between them was complicated due to the new Vista structure. The sharing process is pretty straight-forward if you’re not using password protection…as you just need to drop what you want to share into the Vista Public folder. On the other hand, sharing with password protection becomes a bit more difficult. Basically you need to add a user and set up sharing on the XP machine. But once again, we have a complete tutorial for that situation. Share Files and Folders Between Vista and XP Machines Sharing Between Windows 7 with Homegroup If you have one or more Windows 7 machine, sharing files and devices becomes extremely easy with the Homegroup feature. It’s as simple as creating a Homegroup on on machine then joining the other to it. It allows you to stream media, control what data is shared, and can also be password protected. If you don’t want to make your Windows 7 machines part of the same Homegroup, you can still share files through the Public Folder, and setup a printer to be shared as well.   Use the Homegroup Feature in Windows 7 to Share Printers and Files Create a Homegroup & Join a New Computer To It Change which Files are Shared in a Homegroup Windows Home Server If you want an ultimate setup that creates a centralized location to share files between all systems on your home network, regardless of the operating system, then set up a Windows Home Server. It allows you to centralize your important documents and digital media files on one box and provides easy access to data and the ability to stream media to other machines on your network. Not only that, but it provides easy backup of all your machines to the server, in case disaster strikes. How to Install and Setup Windows Home Server How to Manage Shared Folders on Windows Home Server Conclusion The biggest annoyance is dealing with printers that have a different set of drivers for each OS. There is no real easy way to solve this problem. Our best advice is to try to connect it to one machine, and if the drivers won’t work, hook it up to the other computer and see if that works. Each printer manufacturer is different, and Windows doesn’t always automatically install the correct drivers for the device. We hope this guide helps you share your data between whichever Microsoft OS scenario you might run into! Here are some other articles that will help you accomplish your home networking needs: Share a Printer on a Home Network from Vista or XP to Windows 7 How to Share a Folder the XP Way in Windows Vista Similar Articles Productive Geek Tips Delete Wrong AutoComplete Entries in Windows Vista MailSvchost Viewer Shows Exactly What Each svchost.exe Instance is DoingFixing "BOOTMGR is missing" Error While Trying to Boot Windows VistaShow Hidden Files and Folders in Windows 7 or VistaAdd Color Coding to Windows 7 Media Center Program Guide TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Icelandic Volcano Webcams Open Multiple Links At One Go NachoFoto Searches Images in Real-time Office 2010 Product Guides Google Maps Place marks – Pizza, Guns or Strip Clubs Monitor Applications With Kiwi

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  • Integrate Nitro PDF Reader with Windows 7

    - by Matthew Guay
    Would you like a lightweight PDF reader that integrates nicely with Office and Windows 7?  Here we look at the new Nitro PDF Reader, a nice PDF viewer that also lets you create and markup PDF files. Adobe Reader is the de-facto PDF viewer, but it only lets you view PDFs and not much else.  Additionally, it doesn’t fully integrate with 64-bit editions of Vista and Windows 7.  There are many alternate PDF readers, but Nitro PDF Reader is a new entry into this field that offers more features than most PDF readers.  From the creators of the popular free PrimoPDF printer, the new Reader lets you create PDFs from a variety of file formats and markup existing PDFs with notes, highlights, stamps, and more in addition to viewing PDFs.  It also integrates great with Windows 7 using the Office 2010 ribbon interface. Getting Started Download the free Nitro PDF Reader (link below) and install as normal.  Nitro PDF Reader has separate versions for 32 & 64-bit editions of Windows, so download the correct one for your computer. Note:  Nitro PDF Reader is still in Beta testing, so only install if you’re comfortable with using beta software. On first run, Nitro PDF Reader will ask if you want to make it the default PDF viewer.  If you don’t want to, make sure to uncheck the box beside Always perform this check to keep it from opening this prompt every time you use it. It will also open an introductory PDF the first time you run it so you can quickly get acquainted with its features. Windows 7 Integration One of the first things you’ll notice is that Nitro PDF Reader integrates great with Windows 7.  The ribbon interface fits right in with native applications such as WordPad and Paint, as well as Office 2010. If you set Nitro PDF Reader as your default PDF viewer, you’ll see thumbnails of your PDFs in Windows Explorer. If you turn on the Preview Pane, you can read full PDFs in Windows Explorer.  Adobe Reader lets you do this in 32 bit versions, but Nitro PDF works in 64 bit versions too. The PDF preview even works in Outlook.  If you receive an email with a PDF attachment, you can select the PDF and view it directly in the Reading Pane.  Click the Preview file button, and you can uncheck the box at the bottom so PDFs will automatically open for preview if you want.   Now you can read your PDF attachments in Outlook without opening them separately.  This works in both Outlook 2007 and 2010. Edit your PDFs Adobe Reader only lets you view PDF files, and you can’t save data you enter in PDF forms.  Nitro PDF Reader, however, gives you several handy markup tools you can use to edit your PDFs.  When you’re done, you can save the final PDF, including information entered into forms. With the ribbon interface, it’s easy to find the tools you want to edit your PDFs. Here we’ve highlighted text in a PDF and added a note to it.  We can now save these changes, and they’ll look the same in any PDF reader, including Adobe Reader. You can also enter new text in PDFs.  This will open a new tab in the ribbon, where you can select basic font settings.  Select the Click To Finish button in the ribbon when you’re finished editing text.   Or, if you want to use the text or pictures from a PDF in another application, you can choose to extract them directly in Nitro PDF Reader.  Create PDFs One of the best features of Nitro PDF Reader is the ability to create PDFs from almost any file.  Nitro adds a new virtual printer to your computer that creates PDF files from anything you can print.  Print your file as normal, but select the Nitro PDF Creator (Reader) printer. Enter a name for your PDF, select if you want to edit the PDF properties, and click Create. If you choose to edit the PDF properties, you can add your name and information to the file, select the initial view, encrypt it, and restrict permissions. Alternately, you can create a PDF from almost any file by simply drag-and-dropping it into Nitro PDF Reader.  It will automatically convert the file to PDF and open it in a new tab in Nitro PDF. Now from the File menu you can send the PDF as an email attachment so anyone can view it. Make sure to save the PDF before closing Nitro, as it does not automatically save the PDF file.   Conclusion Nitro PDF Reader is a nice alternative to Adobe Reader, and offers some features that are only available in the more expensive Adobe Acrobat.  With great Windows 7 integration, including full support for 64-bit editions, Nitro fits in with the Windows and Office experience very nicely.  If you have tried out Nitro PDF Reader leave a comment and let us know what you think. Link Download Nitro PDF Reader Similar Articles Productive Geek Tips Install Adobe PDF Reader on Ubuntu EdgySubscribe to RSS Feeds in Chrome with a Single ClickChange Default Feed Reader in FirefoxFix for Windows Explorer Folder Pane in XP Becomes Grayed OutRemove "Please wait while the document is being prepared for reading" Message in Adobe Reader 8 TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Xobni Plus for Outlook All My Movies 5.9 CloudBerry Online Backup 1.5 for Windows Home Server Snagit 10 tinysong gives a shortened URL for you to post on Twitter (or anywhere) 10 Superb Firefox Wallpapers OpenDNS Guide Google TV The iPod Revolution Ultimate Boot CD can help when disaster strikes

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  • Installing SharePoint 2010 and PowerPivot for SharePoint on Windows 7

    - by smisner
    Many people like me want (or need) to do their business intelligence development work on a laptop. As someone who frequently speaks at various events or teaches classes on all subjects related to the Microsoft business intelligence stack, I need a way to run multiple server products on my laptop with reasonable performance. Once upon a time, that requirement meant only that I had to load the current version of SQL Server and the client tools of choice. In today's post, I'll review my latest experience with trying to make the newly released Microsoft BI products work with a Windows 7 operating system.The entrance of Microsoft Office SharePoint Server 2007 into the BI stack complicated matters and I started using Virtual Server to establish a "suitable" environment. As part of the team that delivered a lot of education as part of the Yukon pre-launch activities (that would be SQL Server 2005 for the uninitiated), I was working with four - yes, four - virtual servers. That was a pretty brutal workload for a 2GB laptop, which worked if I was very, very careful. It could also be a finicky and unreliable configuration as I learned to my dismay at one TechEd session several years ago when I had to reboot a very carefully cached set of servers just minutes before my session started. Although it worked, it came back to life very, very slowly much to the displeasure of the audience. They couldn't possibly have been less pleased than me.At that moment, I resolved to get the beefiest environment I could afford and consolidate to a single virtual server. Enter the 4GB 64-bit laptop to preserve my sanity and my livelihood. Likewise, for SQL Server 2008, I managed to keep everything within a single virtual server and I could function reasonably well with this approach.Now we have SQL Server 2008 R2 plus Office SharePoint Server 2010. That means a 64-bit operating system. Period. That means no more Virtual Server. That means I must use Hyper-V or another alternative. I've heard alternatives exist, but my few dabbles in this area did not yield positive results. It might have been just me having issues rather than any failure of those technologies to adequately support the requirements.My first run at working with the new BI stack configuration was to set up a 64-bit 4GB laptop with a dual-boot to run Windows Server 2008 R2 with Hyper-V. However, I was generally not happy with running Windows Server 2008 R2 on my laptop. For one, I couldn't put it into sleep mode, which is helpful if I want to prepare for a presentation beforehand and then walk to the podium without the need to hold my laptop in its open state along the way (my strategy at the TechEd session long, long ago). Secondly, it was finicky with projectors. I had issues from time to time and while I always eventually got it to work, I didn't appreciate those nerve-wracking moments wondering whether this would be the time that it wouldn't work.Somewhere along the way, I learned that it was possible to load SharePoint 2010 in a Windows 7 which piqued my interest. I had just acquired a new laptop running Windows 7 64-bit, and thought surely running the BI stack natively on my laptop must be better than running Hyper-V. (I have not tried booting to Hyper-V VHD yet, but that's on my list of things to try so the jury of one is still out on this approach.) Recently, I had to build up a server with the RTM versions of SQL Server 2008 R2 and Sharepoint Server 2010 and decided to follow suit on my Windows 7 Ultimate 64-bit laptop. The process is slightly different, but I'm happy to report that it IS possible, although I had some fits and starts along the way.DISCLAIMER: These products are NOT intended to be run in production mode on the Windows 7 operating system. The configuration described in this post is strictly for development or learning purposes and not supported by Microsoft. If you have trouble, you will NOT get help from them. I might be able to help, but I provide no guarantees of my ability or availablity to help. I won't provide the step-by-step instructions in this post as there are other resources that provide these details, but I will provide an overview of my approach, point you to the relevant resources, describe some of the problems I encountered, and explain how I addressed those problems to achieve my desired goal.Because my goal was not simply to set up SharePoint Server 2010 on my laptop, but specifically PowerPivot for SharePoint, I started out by referring to the installation instructions at the PowerPiovt-Info site, but mainly to confirm that I was performing steps in the proper sequence. I didn't perform the steps in Part 1 because those steps are applicable only to a server operating system which I am not running on my laptop. Then, the instructions in Part 2, won't work exactly as written for the same reason. Instead, I followed the instructions on MSDN, Setting Up the Development Environment for SharePoint 2010 on Windows Vista, Windows 7, and Windows Server 2008. In general, I found the following differences in installation steps from the steps at PowerPivot-Info:You must copy the SharePoint installation media to the local drive so that you can edit the config.xml to allow installation on a Windows client.You also have to manually install the prerequisites. The instructions provides links to each item that you must manually install and provides a command-line instruction to execute which enables required Windows features.I will digress for a moment to save you some grief in the sequence of steps to perform. I discovered later that a missing step in the MSDN instructions is to install the November CTP Reporting Services add-in for SharePoint. When I went to test my SharePoint site (I believe I tested after I had a successful PowerPivot installation), I ran into the following error: Could not load file or assembly 'RSSharePointSoapProxy, Version=10.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91' or one of its dependencies. The system cannot find the file specified. I was rather surprised that Reporting Services was required. Then I found an article by Alan le Marquand, Working Together: SQL Server 2008 R2 Reporting Services Integration in SharePoint 2010,that instructed readers to install the November add-in. My first reaction was, "Really?!?" But I confirmed it in another TechNet article on hardware and software requirements for SharePoint Server 2010. It doesn't refer explicitly to the November CTP but following the link took me there. (Interestingly, I retested today and there's no longer any reference to the November CTP. Here's the link to download the latest and greatest Reporting Services Add-in for SharePoint Technologies 2010.) You don't need to download the add-in anymore if you're doing a regular server-based installation of SharePoint because it installs as part of the prerequisites automatically.When it was time to start the installation of SharePoint, I deviated from the MSDN instructions and from the PowerPivot-Info instructions:On the Choose the installation you want page of the installation wizard, I chose Server Farm.On the Server Type page, I chose Complete.At the end of the installation, I did not run the configuration wizard.Returning to the PowerPivot-Info instructions, I tried to follow the instructions in Part 3 which describe installing SQL Server 2008 R2 with the PowerPivot option. These instructions tell you to choose the New Server option on the Setup Role page where you add PowerPivot for SharePoint. However, I ran into problems with this approach and got installation errors at the end.It wasn't until much later as I was investigating an error that I encountered Dave Wickert's post that installing PowerPivot for SharePoint on Windows 7 is unsupported. Uh oh. But he did want to hear about it if anyone succeeded, so I decided to take the plunge. Perseverance paid off, and I can happily inform Dave that it does work so far. I haven't tested absolutely everything with PowerPivot for SharePoint but have successfully deployed a workbook and viewed the PowerPivot Management Dashboard. I have not yet tested the data refresh feature, but I have installed. Continue reading to see how I accomplished my objective.I unintalled SQL Server 2008 R2 and started again. I had different problems which I don't recollect now. However, I uninstalled again and approached installation from a different angle and my next attempt succeeded. The downside of this approach is that you must do all of the things yourself that are done automatically when you install PowerPivot as a new server. Here are the steps that I followed:Install SQL Server 2008 R2 to get a database engine instance installed.Run the SharePoint configuration wizard to set up the SharePoint databases.In Central Administration, create a Web application using classic mode authentication as per a TechNet article on PowerPivot Authentication and Authorization.Then I followed the steps I found at How to: Install PowerPivot for SharePoint on an Existing SharePoint Server. Especially important to note - you must launch setup by using Run as administrator. I did not have to manually deploy the PowerPivot solution as the instructions specify, but it's good to know about this step because it tells you where to look in Central Administration to confirm a successful deployment.I did spot some incorrect steps in the instructions (at the time of this writing) in How To: Configure Stored Credentials for PowerPivot Data Refresh. Specifically, in the section entitled Step 1: Create a target application and set the credentials, both steps 10 and 12 are incorrect. They tell you to provide an actual Windows user name and password on the page where you are simply defining the prompts for your application in the Secure Store Service. To add the Windows user name and password that you want to associate with the application - after you have successfully created the target application - you select the target application and then click Set credentials in the ribbon.Lastly, I followed the instructions at How to: Install Office Data Connectivity Components on a PowerPivot server. However, I have yet to test this in my current environment.I did have several stops and starts throughout this process and edited those out to spare you from reading non-essential information. I believe the explanation I have provided here accurately reflect the steps I followed to produce a working configuration. If you follow these steps and get a different result, please let me know so that together we can work through the issue and correct these instructions. I'm sure there are many other folks in the Microsoft BI community that will appreciate the ability to set up the BI stack in a Windows 7 environment for development or learning purposes. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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