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  • XPathNavigator in Silverlight

    - by vladimir
    I have a code library that makes heavy use of XPathNavigator to parse some specific xml document. The xml document is cross-referenced, meaning that an element can reference another which has not yet been encountered during parsing: <ElementA ...> <DependentElementX id="1234"> </ElementA> <ElementX id="1234" .../> The document doesn't really look like this, but the point is that 1) there is an xml schema that enforces the overall document structure, 2) elements inside the document can reference each other using some IDs, and 3) there is quite a few such cross references between different elements in the document. The document is parsed in two phases. In the first pass I walk through the document XPathDocument doc = ...; XPathNavigator nav = doc.CreateNavigator(); nav.MoveToRoot(); nav.MoveToFirstChild()... and occasionally 'bookmark' the current position (element) in the document using XPathNavigator.Clone() method. This gives me a lightweight instance of an XPathNavigator which I can store somewhere and use later to jump back to a particular place (element) in my document. Once I have enough information collected in the first pass (for example, I have made sure there is indeed an ElementX with an id='1234'), I jump back to saved bookmarks (using those saved XPathNavigators) and complete the parsing. Well, now I'm about to use this library in Silverlight 3.0 and to my horror the XPathNavigator is not in the System.Xml assembly. Questions: 1) Am I missing something obvious (i.e. XPathNavigator does exist in some shape or form, for example in a toolkit or a freeware library)? 2) If I do have to make modifications in the code, what would be the best way to go? Ideally, I would like to make minimal changes, not to rewrite 80% of the code just to be able to use something like XLinq. To resume, in case I have to give up XPathNavigator, all I need is a way to bookmark places in my document and to get back to them so that I can continue to iterate from where I left off. Thanks in advance for any help/ideas.

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  • What could cause this difference in behaviour from iphone OS3.0 to iOS4.0?

    - by frankodwyer
    I am getting a strange EXC_BAD_ACCESS error when running my app on iOS4. The app has been pretty solid on OS3.x for some time - not even seeing crash logs in this area of the code (or many at all) in the wild. I've tracked the error down to this code: main class: - (void) sendPost:(PostRequest*)request { NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; NSURLResponse* response; NSError* error; NSData *serverReply = [NSURLConnection sendSynchronousRequest:request.request returningResponse:&response error:&error]; ServerResponse* serverResponse=[[ServerResponse alloc] initWithResponse:response error:error data:serverReply]; [request.objectToNotifyWhenDone performSelectorOnMainThread:request.targetToNotifyWhenDone withObject:serverResponse waitUntilDone:YES]; [pool drain]; } (Note: sendPost is run on a separate thread for each invocation of it. PostRequest is just a class to encapsulate a request and a selector to notify when complete) ServerResponse.m: @synthesize response; @synthesize replyString; @synthesize error; @synthesize plist; - (ServerResponse*) initWithResponse:(NSURLResponse*)resp error:(NSError*)err data:(NSData*)serverReply { self.response=resp; self.error=err; self.plist=nil; self.replyString=nil; if (serverReply) { self.replyString = [[[NSString alloc] initWithBytes:[serverReply bytes] length:[serverReply length] encoding: NSASCIIStringEncoding] autorelease]; NSPropertyListFormat format; NSString *errorStr; plist = [NSPropertyListSerialization propertyListFromData:serverReply mutabilityOption:NSPropertyListImmutable format:&format errorDescription:&errorStr]; } return self; } ServerResponse.h: @property (nonatomic, retain) NSURLResponse* response; @property (nonatomic, retain) NSString* replyString; @property (nonatomic, retain) NSError* error; @property (nonatomic, retain) NSDictionary* plist; - (ServerResponse*) initWithResponse:(NSURLResponse*)response error:(NSError*)error data:(NSData*)serverReply; This reliably crashes with a bad access in the line: self.error=err; ...i.e. in the synthesized property setter! I'm stumped as to why this should be, given the code worked on the previous OS and hasn't changed since (even the binary compiled with the previous SDK crashes the same way, but not on OS3.0) - and given it is a simple property method. Any ideas? Could the NSError implementation have changed between releases or am I missing something obvious?

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  • trouble with boost::filesystem::wrecursive_directory_iterator

    - by Dogmatixed
    I'm trying to write a program to help me manage my iTunes library, including removing duplicates and cataloging certain things. At this point I'm still just trying to get it to walk through all the folders, and have run into a problem: I have a small amount of Japanese music, where the artist and/or album is written in Japanese characters. Because of how iTunes arranges things in its library the directories contain these characters. "shouldn't be a problem, though." I thought, because the boost::filesystem library has a wide character version of its recursive iterator. but when I actually try to use it, it seems to completely stop when it hits the first Japanese char. complete stop as in it doesn't finish printing the line, no carriage return or anything. now, I'm still pretty new to programming, so I'm assuming it's my mistake, anyone know why this is happening? here's what I think is the relevant code: fs::wrecursive_directory_iterator end_it; int i; try { for(fs::wrecursive_directory_iterator rec_it(full_path); rec_it != end_it; ++rec_it) { for(i = 0; i < rec_it.level(); i++) { out << "\t"; } out << rec_it->string() << std::endl; } } catch(std::exception e) { out << "something went wrong: " << e.what(); } and from my output file, minus some of the path: /Test Libs/Combine /Test Libs/Lib1 /Test Libs/Lib1/02 Too Long.m4a /Test Libs/Lib1/03 Like a Hitman, Like a Dancer.mp3 /Test Libs/Lib1/A Certain Ratio /Test Libs/Lib1/A Certain Ratio/Beyond Punk! /Test Libs/Lib1/A Certain Ratio/Unknown Album /Test Libs/Lib1/A Certain Ratio/Unknown Album/Do The Du.mp3 /Test Libs/Lib1/A Certain Ratio/Unknown Album/Shack Up.mp3 /Test Libs/Lib1/ finally, what I expect: /Test Libs/Combine /Test Libs/Lib1 /Test Libs/Lib1/02 Too Long.m4a /Test Libs/Lib1/03 Like a Hitman, Like a Dancer.mp3 /Test Libs/Lib1/A Certain Ratio /Test Libs/Lib1/A Certain Ratio/Beyond Punk! /Test Libs/Lib1/A Certain Ratio/Unknown Album /Test Libs/Lib1/A Certain Ratio/Unknown Album/Do The Du.mp3 /Test Libs/Lib1/A Certain Ratio/Unknown Album/Shack Up.mp3 /Test Libs/Lib1/??? /Test Libs/Lib1/Bring it on /Test Libs/Lib1/04 Bring it on.mp3 any thoughts? Thanks.

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  • Subroutine & GoTo design

    - by sub
    I have a strange question concerning subroutines: As I'm creating a minimal language and I don't want to add high-level loops like while or for I was planning on just adding gotos to keep it Turing-Complete. Now I thought, eww - gotos - I wouldn't want to program in that language if I had to use gotos so often. So I thought about adding subroutines instead. I see the difference as the following: gotos Go to (captain obvious) a previously defined point and continue executing the program from there. Leads to hardly understandable and buggy code, I think that's a fact. subroutines Similiar: You define their starting point somewhere, as you call them the program jumps there - but the subroutine can go back to the point it was called from with return. Okay. Why didn't I just add the more function-like, nice looking subroutines? Because: In order to make return work if I call subroutines from within subroutines from within other subroutines, I'd have to use a stack containing the point where the currently running subroutine came from at top. That would then mean that I would, if I create loops using the subroutines, end up with an extremely memory-eating, overflowing stack with return locations. Not good. Don't think of my subroutines as functions. They are just gotos that return to the point they were called from, they don't actually give back values like the return x; statement in nearly all today's languages. Now to my actual questions: How can I solve the above problem with the stack overflow on loops with subroutines? Do I have to add a separate goto language construct without the return option? Assembler doesn't have loops but as I have seen myJumpPoint:, jnz, jz, retn. That means to me that there must also be a stack containing all the return locations. Am I right with that? What about long running loops then? Don't they overflow the stack/eat memory then? Am I getting the retn symbol in assembler totally wrong? If yes, please explain it to me.

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  • Rails "NoMethodError" with sub-resources

    - by Tchock
    Hi. I'm a newbie Rails developer who is getting the following error when trying to access the 'new' action on my CityController: undefined method `cities_path' for #<#<Class:0x104608c18>:0x104606f08> Extracted source (around line #2): 1: <h1>New City</h1> 2: <%= form_for(@city) do |f| %> 3: <%= f.error_messages %> 4: 5: <div class="field"> As some background, I have a State model with many Cities. I'm getting this error after clicking on the following link coming from a State show page: <p>Add a city: <%= link_to "Add city", new_state_city_path(@state) %></p> When I run 'rake:routes' it says this is a legit route... For more background, here is the CityController 'new' action: def new @city = City.new respond_to do |format| format.html # new.html.erb format.xml { render :xml => @city } end end Here is the (complete) form in the view: <%= form_for(@city) do |f| %> <%= f.error_messages %> <div class="field"> <%= f.label :name %><br /> <%= f.text_field :name %> </div> <div class="actions"> <%= f.submit %> </div> <% end %> This initially made me think that it's a resources/routes issue since it came back with a mention of 'cities_path' (in fact, that's what another person posting to Stack Overflow had wrong (http://stackoverflow.com/questions/845315/rails-error-nomethoderror-my-first-ruby-app). However, that doesn't seem to be the case from what I can see. Here are how my resources look in my routes file: resources :states do resources :cities end I can get it working when they are not sub-resources, but I really need to keep them as sub-resources for my future plans with the app. Any help would be very much appreciated, since I've been racking my brains on this for more hours than I would care to admit... Thanks! (Not sure this matters at all, but I'm running the very latest version of Rails 3 beta2).

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  • paypal IPN sends two different twice

    - by Patrick
    I've come across something a bit strange I was hoping someone with more experience with Paypal can explain, Specifically the IPN feature. It seems I'm getting two very different hits to my IPN listener. The first one always fails, The second one passes. Now I know Paypal tends to send duplicates, But what I've noticed is two very different $_POST arrays being recieved. Here's the respones : [2014-06-08 23:51:19] RAW POST DATA : Array ( [transaction] => Array ( [0] => ILS 20.00 ) [payment_request_date] => Sun Jun 08 13:52:12 PDT 2014 [return_url] => MY_URL [fees_payer] => EACHRECEIVER [ipn_notification_url] => MY_URL [sender_email] => [email protected] //fake email [verify_sign] => ANp5TpLat3.2ylx.cECtVZ..5HejAsVcs05tdVC7RldmeYNJ91SKaqFJ [test_ipn] => 1 [cancel_url] => MY_URL [pay_key] => AP-04B74091M7083584A [action_type] => PAY [transaction_type] => Adaptive Payment PAY [tracking_id] => 13 // This is a number I passed, But it doesn't exist in the 2nd POST [status] => COMPLETED [log_default_shipping_address_in_transaction] => false [charset] => windows-1252 [notify_version] => UNVERSIONED [reverse_all_parallel_payments_on_error] => false ) [2014-06-08 23:51:19] RAW POST DATA : Array ( [transaction_subject] => [payment_date] => 13:52:28 Jun 08, 2014 PDT [txn_type] => web_accept [last_name] => test [residence_country] => US [item_name] => .... (this continues for quite a bit more) .... [payment_fee] => [mc_fee] => 1.78 [mc_gross] => 20.00 [custom] => [charset] => windows-1252 [notify_version] => 3.8 [ipn_track_id] => f93ce8bdd4382 ) My problem The first IPN with the juicy tracking_id fails, the 2nd IPN is verified, But once the IPN is verified I no longer have access to the tracking_id. My questions Why does paypal send two different IPN's Why are they different? Why isn't any of this documented on Paypal? :(

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  • how to implement a "soft barrier" in multithreaded c++

    - by Jason
    I have some multithreaded c++ code with the following structure: do_thread_specific_work(); update_shared_variables(); //checkpoint A do_thread_specific_work_not_modifying_shared_variables(); //checkpoint B do_thread_specific_work_requiring_all_threads_have_updated_shared_variables(); What follows checkpoint B is work that could have started if all threads have reached only checkpoint A, hence my notion of a "soft barrier". Typically multithreading libraries only provide "hard barriers" in which all threads must reach some point before any can continue. Obviously a hard barrier could be used at checkpoint B. Using a soft barrier can lead to better execution time, especially since the work between checkpoints A and B may not be load-balanced between the threads (i.e. 1 slow thread who has reached checkpoint A but not B could be causing all the others to wait at the barrier just before checkpoint B). I've tried using atomics to synchronize things and I know with 100% certainty that is it NOT guaranteed to work. For example using openmp syntax, before the parallel section start with: shared_thread_counter = num_threads; //known at compile time #pragma omp flush Then at checkpoint A: #pragma omp atomic shared_thread_counter--; Then at checkpoint B (using polling): #pragma omp flush while (shared_thread_counter > 0) { usleep(1); //can be removed, but better to limit memory bandwidth #pragma omp flush } I've designed some experiments in which I use an atomic to indicate that some operation before it is finished. The experiment would work with 2 threads most of the time but consistently fail when I have lots of threads (like 20 or 30). I suspect this is because of the caching structure of modern CPUs. Even if one thread updates some other value before doing the atomic decrement, it is not guaranteed to be read by another thread in that order. Consider the case when the other value is a cache miss and the atomic decrement is a cache hit. So back to my question, how to CORRECTLY implement this "soft barrier"? Is there any built-in feature that guarantees such functionality? I'd prefer openmp but I'm familiar with most of the other common multithreading libraries. As a workaround right now, I'm using a hard barrier at checkpoint B and I've restructured my code to make the work between checkpoint A and B automatically load-balancing between the threads (which has been rather difficult at times). Thanks for any advice/insight :)

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  • Using VCL for the web (intraweb) as a trick for adding web interface to a legacy non-tiered (2 tiers

    - by user193655
    My team is maintaining a huge Client Server win32 Delphi application. It is a client/server application (Thick client) that uses DevArt (SDAC) components to connect to SQL Server. The business logic is often "trapped" in Component's event handlers, anyway with some degree of refactoring it is doable to move the business logic in common units (a big part of this work has already been done during refactoring... Maintaing legacy applications someone else wrote is very frustrating, but this is a very common job). Now there is the request of a web interface, I have several options of course, in this question i want to focus on the VCL for the web (intraweb) option. The idea is to use the common code (the same pas files) for both the client/server application and the web application. I heard of many people that moved legacy apps from delphi to intraweb, but here I am trying to keep the Thick client too. The idea is to use common code, may be with some compiler directives to write specific code: {$IFDEF CLIENTSERVER} {here goes the thick client specific code} {$ELSE} {here goes the Intraweb specific code} {$ENDIF} Then another problem is the "migration plan", let's say I have 300 features and on the first release I will have only 50 of them available in the web application. How to keep track of it? I was thinking of (ab)using Delphi interfaces to handle this. For example for the User Authentication I could move all the related code in a procedure and declare an interface like: type IUserAuthentication= interface['{0D57624C-CDDE-458B-A36C-436AE465B477}'] procedure UserAuthentication; end; In this way as I implement the IUserAuthentication interface in both the applications (Thick Client and Intraweb) I know that That feature has been "ported" to the web. Anyway I don't know if this approach makes sense. I made a prototype to simulate the whole process. It works for a "Hello world" application, but I wonder if it makes sense on a large application or this Interface idea is only counter-productive and can backfire. My question is: does this approach make sense? (the Interface idea is just an extra idea, it is not so important as the common code part described above) Is it a viable option? I understand it depends a lot of the kind of application, anyway to be generic my one is in the CRM/Accounting domain, and the number of concurrent users on a single installation is typically less than 20 with peaks of 50. EXTRA COMMENT (UPDATE): I ask this question because since I don't have a n-tier application I see Intraweb as the unique option for having a web application that has common code with the thick client. Developing webservices from the Delphi code makes no sense in my specific case, so the alternative I have is to write the web interface using ASP.NET (duplicating the business logic), but in this case I cannot take advantage of the common code in an easy way. Yes I could use dlls maybe, but my code is not suitable for that.

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  • JSONP context problem

    - by PoweRoy
    I'm using a javascript autocomplete () in a greasemonkey script. On itself it works correctly but I wan't to add JSONP because I want the data from another domain. The code (snippet): function autosuggest(url) { this.suggest_url = url; this.keywords = []; return this.construct(); }; autosuggest.prototype = { construct: function() { return this; }, preSuggest: function() { this.CreateJSONPRequest(this.suggest_url + "foo"); }, CreateJSONPRequest: function(url) { var headID = document.getElementsByTagName("head")[0]; var newScript = document.createElement('script'); newScript.type = 'text/javascript'; newScript.src = url +'&callback=autosuggest.prototype.JSONCallback'; //newScript.async = true; newScript.onload = newScript.onreadystatechange = function() { if (newScript.readyState === "loaded" || newScript.readyState === "complete") { //remove it again newScript.onload = newScript.onreadystatechange = null; if (newScript && newScript.parentNode) { newScript.parentNode.removeChild(newScript); } } } headID.appendChild(newScript); }, JSONCallback: function(data) { if(data) { this.keywords = data; this.suggest(); } }, suggest: function() { //use this.keywords } }; //Add suggestion box to textboxes window.opera.addEventListener('AfterEvent.load', function (e) { var textboxes = document.getElementsByTagName('input'); for (var i = 0; i < textboxes.length; i++) { var tb = textboxes[i]; if (tb.type == 'text') { if (tb.autocomplete == undefined || tb.autocomplete == '' || tb.autocomplete == 'on') { //we handle autosuggestion tb.setAttribute('autocomplete','off'); var obj1 = new autosuggest("http://test.php?q="); } } } }, false); I removed not relevant code. Now when 'preSuggest' is called, it add a script to the header and circumvent the crossdomain problem. Now when the data is received back 'JSONcallback' is called. I can use the data, but when 'Suggest' is I can't use the this.keywords array or this.suggest_url. I think this is because 'JSONcallback' and 'Suggest' are called in a different context. How can I get this working?

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  • quartz: preventing concurrent instances of a job in jobs.xml

    - by Jason S
    This should be really easy. I'm using Quartz running under Apache Tomcat 6.0.18, and I have a jobs.xml file which sets up my scheduled job that runs every minute. What I would like to do, is if the job is still running when the next trigger time rolls around, I don't want to start a new job, so I can let the old instance complete. Is there a way to specify this in jobs.xml (prevent concurrent instances)? If not, is there a way I can share access to an in-memory singleton within my application's Job implementation (is this through the JobExecutionContext?) so I can handle the concurrency myself? (and detect if a previous instance is running) update: After floundering around in the docs, here's a couple of approaches I am considering, but either don't know how to get them to work, or there are problems. Use StatefulJob. This prevents concurrent access... but I'm not sure what other side-effects would occur if I use it, also I want to avoid the following situation: Suppose trigger times would be every minute, i.e. trigger#0 = at time 0, trigger #1 = 60000msec, #2 = 120000, #3 = 180000, etc. and the trigger#0 at time 0 fires my job which takes 130000msec. With a plain Job, this would execute triggers #1 and #2 while job trigger #0 is still running. With a StatefulJob, this would execute triggers #1 and #2 in order, immediately after #0 finishes at 130000. I don't want that, I want #1 and #2 not to run and the next trigger that runs a job should take place at #3 (180000msec). So I still have to do something else with StatefulJob to get it to work the way I want, so I don't see much of an advantage to using it. Use a TriggerListener to return true from vetoJobExecution(). Although implementing the interface seems straightforward, I have to figure out how to setup one instance of a TriggerListener declaratively. Can't find the docs for the xml file. Use a static shared thread-safe object (e.g. a semaphore or whatever) owned by my class that implements Job. I don't like the idea of using singletons via the static keyword under Tomcat/Quartz, not sure if there are side effects. Also I really don't want them to be true singletons, just something that is associated with a particular job definition. Implement my own Trigger which extends SimpleTrigger and contains shared state that could run its own TriggerListener. Again, I don't know how to setup the XML file to use this trigger rather than the standard <trigger><simple>...</simple></trigger>.

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  • How to call a JavaScript function from one frame to another in Chrome/Webkit with file protocol

    - by bambax
    I have developed an application that has a list of items in one frame; when one clicks on an item it does something in another frame (loads an image). This used to work fine in all browsers, including Chrome 3; now it still works fine in Firefox but in recent versions of Chrome (I believe since 4) it throws this error: Unsafe JavaScript attempt to access frame with URL (...) from frame with URL (...). Domains, protocols and ports must match. This is obviously a security "feature" but is it possible to get around it? Here is a simple test: index.html: <html> <frameset cols="50%,50%"> <frame src="left.html" name="left"/> <frame src="right.html" name="right"/> </frameset> </html> left.html: <html> <body> <a href="javascript:parent.right.test('hello');">click me</a> </body> </html> right.html: <html> <body> <script> function test(msg) { alert(msg); } </script> </body> </html> The above works in Firefox 3.6 and Chrome 3 but in Chrome 5 it throws the above error... Edit: added the @cols attribute to the frameset element in fact it works in Chrome if and only if the pages are served with the http protocol (and from the same domain) but my problem is when pages are local and served from a file:// protocol. Then it works in Firefox (all versions) and Chrome 3 but not Chrome 5 (I don't have Chrome 4 so I'm not shure about that specific version (and don't know if it's even possible to download a specific Chrome version?) -- but for Chrome 5 I'm very sure it doesn't work).

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  • PayPal sandbox Buy Now Problem

    - by Tushar Ahirrao
    Hi , I have paypal sandbox test account. I want to create a 'buy Now' button. I am trying it with GWT. But its even not working with simple HTML form. It displays a 'Buy Now' button on HTML page and after clicking on it redirects to PayPal site. Where it ask to login to buy product but after that it goes on displying message: The email address or password you have entered does not match our records. Please try again. I am using buyer user to purchase product. I am pretty sure about the username and password. Providing here the simple HTML form which I am trying: <form action="https://www.paypal.com/cgi-bin/webscr" method="post" id="payPalForm"> <input type="hidden" name="item_number" value="1"> <input type="hidden" name="cmd" value="_xclick"> <input type="hidden" name="no_note" value="1"> <input type="hidden" name="business" value="[email protected]"> <input type="hidden" name="lc" value="US"> <input type="hidden" name="button_subtype" value="services"> <input type="hidden" name="cn" value="Add special instructions to the seller"> <input type="hidden" name="no_shipping" value="2"> <input type="hidden" name="rm" value="1"> <input type="hidden" name="bn" value="PP-BuyNowBF:btn_paynow_SM.gif:NonHosted"> <input type="hidden" name="variables" value="http://google.com"> <input type="hidden" name="cancel_return" value="http://google.com"> <input type="hidden" name="notify_url" value="http://google.com"> <input type="hidden" name="return" value="http://freelanceswitch.com/payment-complete /"> <input type="hidden" name="currency_code" value="USD"> <input name="item_name" type="hidden" value="Deal Name"> <input name="amount" type="hidden" value="500"> <input type="submit" name="Submit" value="Submit"> </form> Please advice. Thank you.

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  • Changing the itemsSource of a treeview makes it's children invisible, when they were already display

    - by Marnix Kraus
    I found some strange problem in WPF, using the itemsSource of a treeview. I hope I can make this specific problem clear for you. First; a story. There is a treeview. It has a list with treeviewitems as itemsSource. This list is called _roots. There is another list, called _leafs. For as in a treeview, the _roots contain the _leafs in some hierarchical way. For example: <TreeviewItem Header="Jungle"> <TreeviewItem> <SpecialTreeviewItem Header="Monkey"/> <SpecialTreeviewItem Header="Apple"/> </TreeviewItem> </TreeviewItem> Now I am trying to switch between these two lists as itemsSource. It seemed to work fine, but it doesn't: When the Jungle-item is un-expanded, and I change the itemsSource to _leafs, and change it back again to _roots, everything works fine and all items can be expanded and showed. But when the Jungle-item is expanded (and the special items are already visible) and I change it to the _leafs itemsSource, and then change the itemsSource back to _roots, all special items have disappeared!! Also, when I do the same as case 2, but first un-expand the Jungle-item again, the special items also disappear. I did a lot of debugging, before posting this question here and come to the following conclusion: Printing on the event: visibility changed, the visibility is set to false for all items that were already visible (that is, when _roots become visible, the special items become invisible (because they were already visible)) So, IsVisible is false for the items, but Visibility = Visible. Which is a bit strange. The problem seems to depend on the use of the _roots list, which in a certain way contain the _leafs. When I change the itemsSource to different lists with special items in it, everything works fine. The hierarchical structure of the _roots make this thing broken. I hope that this is a complete overview of my problem. Help would be appreciated.

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  • How to optimize my PostgreSQL DB for prefix search?

    - by asmaier
    I have a table called "nodes" with roughly 1.7 million rows in my PostgreSQL db =#\d nodes Table "public.nodes" Column | Type | Modifiers --------+------------------------+----------- id | integer | not null title | character varying(256) | score | double precision | Indexes: "nodes_pkey" PRIMARY KEY, btree (id) I want to use information from that table for autocompletion of a search field, showing the user a list of the ten titles having the highest score fitting to his input. So I used this query (here searching for all titles starting with "s") =# explain analyze select title,score from nodes where title ilike 's%' order by score desc; QUERY PLAN ----------------------------------------------------------------------------------------------------------------------- Sort (cost=64177.92..64581.38 rows=161385 width=25) (actual time=4930.334..5047.321 rows=161264 loops=1) Sort Key: score Sort Method: external merge Disk: 5712kB -> Seq Scan on nodes (cost=0.00..46630.50 rows=161385 width=25) (actual time=0.611..4464.413 rows=161264 loops=1) Filter: ((title)::text ~~* 's%'::text) Total runtime: 5260.791 ms (6 rows) This was much to slow for using it with autocomplete. With some information from Using PostgreSQL in Web 2.0 Applications I was able to improve that with a special index =# create index title_idx on nodes using btree(lower(title) text_pattern_ops); =# explain analyze select title,score from nodes where lower(title) like lower('s%') order by score desc limit 10; QUERY PLAN ------------------------------------------------------------------------------------------------------------------------------------------ Limit (cost=18122.41..18122.43 rows=10 width=25) (actual time=1324.703..1324.708 rows=10 loops=1) -> Sort (cost=18122.41..18144.60 rows=8876 width=25) (actual time=1324.700..1324.702 rows=10 loops=1) Sort Key: score Sort Method: top-N heapsort Memory: 17kB -> Bitmap Heap Scan on nodes (cost=243.53..17930.60 rows=8876 width=25) (actual time=96.124..1227.203 rows=161264 loops=1) Filter: (lower((title)::text) ~~ 's%'::text) -> Bitmap Index Scan on title_idx (cost=0.00..241.31 rows=8876 width=0) (actual time=90.059..90.059 rows=161264 loops=1) Index Cond: ((lower((title)::text) ~>=~ 's'::text) AND (lower((title)::text) ~<~ 't'::text)) Total runtime: 1325.085 ms (9 rows) So this gave me a speedup of factor 4. But can this be further improved? What if I want to use '%s%' instead of 's%'? Do I have any chance of getting a decent performance with PostgreSQL in that case, too? Or should I better try a different solution (Lucene?, Sphinx?) for implementing my autocomplete feature?

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  • jquery ajax error cannot find url outside of debug mode

    - by John Orlandella Jr.
    I inherited some code two weeks ago that is using the jquery.ajax method to connect to a .NET web service. Here is the piece of code give me the trouble... if (MSCTour.AppSettings.OFFLINE !== 'TRUE') { $.ajax({ url: url, data: json, type: "POST", contentType: "application/json", timeout: 10000, dataType: "json", // not "json" we'll parse success: function(res){ if (!callback) { return; } /* // *** Use json library so we can fix up MS AJAX dates */ var result = ""; if (res !== "") { try { result = $.evalJSON(res); } catch (e) { result = {}; bare = true; } } /* // *** Bare message IS result */ if (bare) { callback(result); return; } /* // *** Wrapped message contains top level object node // *** strip it off */ for (var property in result) { callback(result[property]); break; } }, error: function(xhr,status,error){ if (status === 'parsererror') {} else {return error;} }, complete: function(res, status){ if (callback) { if ((status != 'success' && status != 'error') || status === 'parsererror' || (status === 'timeout' && res !== '')) { try { result = $.secureEvalJSON(res); } catch (e) { result = {}; bare = true; } callback(res); } } return; } }); } The url variable at this point equals /testsite/service.svc/GetItems Now here is where my problem lies... When running this site out of debug mode through visual studio I am not having any problem connecting to the database through the web service and seeing all my data, for both viewing and updating. When I go through the normal web server for the same site, on the same page, no data is showing up. When I put a break on the error portion of the code above in firebug this is information I am getting in the image linked below. link text I am getting what appears to be a 404 error, but when I look on the server all of the files are in the right place... coupled with the fact that it works when in debug mode, I think I am slowly going crazy staring at these same lines of code trying to find the needle in the haystack. Any help or just a direction to look in would be greatly appreciated.

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  • design for a wrapper around command-line utilities

    - by hatchetman82
    im trying to come up with a design for a wrapper for use when invoking command line utilities in java. the trouble with runtime.exec() is that you need to keep reading from the process' out and err streams or it hangs when it fills its buffers. this has led me to the following design: public class CommandLineInterface { private final Thread stdOutThread; private final Thread stdErrThread; private final OutputStreamWriter stdin; private final History history; public CommandLineInterface(String command) throws IOException { this.history = new History(); this.history.addEntry(new HistoryEntry(EntryTypeEnum.INPUT, command)); Process process = Runtime.getRuntime().exec(command); stdin = new OutputStreamWriter(process.getOutputStream()); stdOutThread = new Thread(new Leech(process.getInputStream(), history, EntryTypeEnum.OUTPUT)); stdOutThread.setDaemon(true); stdOutThread.start(); stdErrThread = new Thread(new Leech(process.getErrorStream(), history, EntryTypeEnum.ERROR)); stdErrThread.setDaemon(true); stdErrThread.start(); } public void write(String input) throws IOException { this.history.addEntry(new HistoryEntry(EntryTypeEnum.INPUT, input)); stdin.write(input); stdin.write("\n"); stdin.flush(); } } public class Leech implements Runnable{ private final InputStream stream; private final History history; private final EntryTypeEnum type; private volatile boolean alive = true; public Leech(InputStream stream, History history, EntryTypeEnum type) { this.stream = stream; this.history = history; this.type = type; } public void run() { BufferedReader reader = new BufferedReader(new InputStreamReader(stream)); String line; try { while(alive) { line = reader.readLine(); if (line==null) break; history.addEntry(new HistoryEntry(type, line)); } } catch (Exception e) { e.printStackTrace(); } } } my issue is with the Leech class (used to "leech" the process' out and err streams and feed them into history - which acts like a log file) - on the one hand reading whole lines is nice and easy (and what im currently doing), but it means i miss the last line (usually the prompt line). i only see the prompt line when executing the next command (because there's no line break until that point). on the other hand, if i read characters myself, how can i tell when the process is "done" ? (either complete or waiting for input) has anyone tried something like waiting 100 millis since the last output from the process and declaring it "done" ? any better ideas on how i can implement a nice wrapper around things like runtime.exec("cmd.exe") ?

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  • Jqeury Validate() special function

    - by kevin
    Hi there, i'm using the Jquery validate() plugin for some forms and it goes great. The only thing is that i have an input field that requires a special validation process. Here is how it goes: The Jquery validate plugin is called in the domready for all the required fields. Here is an exemple for an input: <li> <label for="nome">Nome completo*</label> <input name="nome" type="text" id="nome" class="required"/> </li> And here is how i call my special function: <li> <span id="sprytextfield1"> <label for="cpf">CPF* (xxxxxxxxxxx)</label> <input name="cpf" type="text" id="cpf" maxlength="15" class="required" /> <span class="textfieldInvalidFormatMsg">CPF Inv&aacute;lido.</span> </span> </li> And at the bottom of the file i call the Spry function: <script type="text/javascript"> <!-- var sprytextfield1 = new Spry.Widget.ValidationTextField("sprytextfield1","cpf"); //--> </script> Of course i call the Spry css and js files in the head section as well as my special-validate.js. When i just use the Jquery validate() plugin and click on the send button, the page goes automatically back to the first mistaken input field and shows the error type (not a number, not a valid email etc.). But with this new function, this "going-back-to-the-first-mistake" feature doesnt work, of course, because the validate() function sees it all good. I already added a rule for another form (about pictures upload) and it goes like this: $("#commentForm").validate({ rules: { foto34: { required: true, accept: "jpg|png|gif" } } }); Now my question is, how can i add the special validation function as a rule of the whole validation process ? Here is the page to understand it better: link text and the special field is the first one: CPF. Hope i was clear explaining my problem. Thanks in advance. kevin

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  • C# Spell checker Problem

    - by reggie
    I've incorporated spell check into my win forms C# project. This is my code. public void CheckSpelling() { try { // declare local variables to track error count // and information int SpellingErrors = 0; string ErrorCountMessage = string.Empty; // create an instance of a word application Microsoft.Office.Interop.Word.Application WordApp = new Microsoft.Office.Interop.Word.Application(); // hide the MS Word document during the spellcheck //WordApp.WindowState = WdWindowState.wdWindowStateMinimize; // check for zero length content in text area if (this.Text.Length > 0) { WordApp.Visible = false; // create an instance of a word document _Document WordDoc = WordApp.Documents.Add(ref emptyItem, ref emptyItem, ref emptyItem, ref oFalse); // load the content written into the word doc WordDoc.Words.First.InsertBefore(this.Text); // collect errors form new temporary document set to contain // the content of this control Microsoft.Office.Interop.Word.ProofreadingErrors docErrors = WordDoc.SpellingErrors; SpellingErrors = docErrors.Count; // execute spell check; assumes no custom dictionaries WordDoc.CheckSpelling(ref oNothing, ref oIgnoreUpperCase, ref oAlwaysSuggest, ref oNothing, ref oNothing, ref oNothing, ref oNothing, ref oNothing, ref oNothing, ref oNothing, ref oNothing, ref oNothing); // format a string to contain a report of the errors detected ErrorCountMessage = "Spell check complete; errors detected: " + SpellingErrors; // return corrected text to control's text area object first = 0; object last = WordDoc.Characters.Count - 1; this.Text = WordDoc.Range(ref first, ref last).Text; } else { // if nothing was typed into the control, abort and inform user ErrorCountMessage = "Unable to spell check an empty text box."; } WordApp.Quit(ref oFalse, ref emptyItem, ref emptyItem); System.Runtime.InteropServices.Marshal.ReleaseComObject(WordApp); // return report on errors corrected // - could either display from the control or change this to // - return a string which the caller could use as desired. // MessageBox.Show(ErrorCountMessage, "Finished Spelling Check"); } catch (Exception e) { MessageBox.Show(e.ToString()); } } The spell checker works well, the only problem is when I try to move the spell checker the main form blurs up for some reason. Also when I close the spell checker the main form is back to normal. It seems like it is opening up Microsoft word then hiding the window, only allowing the spell checker to be seen. Please help.

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  • _heapwalk reports _HEAPBADNODE, causes breakpoint or loops endlessly

    - by Stefan Hubert
    I use _heapwalk to gather statistics about the Process' standard heap. Under certain circumstances i observe unexpected behaviours like: _HEAPBADNODE is returned some breakpoint is triggered inside _heapwalk, telling me the heap might got corrupted access violation inside _heapWalk. I saw different behaviours on different Computers. On one Windows XP 32 bit machine everything looked fine, whereas on two Windows XP 64 bit machines i saw the mentioned symptoms. I saw this behaviour only if LowFragmentationHeap was enabled. I played around a bit. I walked the heap several times right one after another inside my program. First time doing nothing in between the subsequent calls to _heapWalk (everything fine). Then again, this time doing some stuff (for gathering statistics) in between two subsequent calls to _heapWalk. Depending upon what I did there, I sometimes got the described symptoms. Here finally a question: What exactly is safe and what is not safe to do in between two subsequent calls to _heapWalk during a complete heap walk run? Naturally, i shall not manipulate the heap. Therefore i doublechecked that i don't call new and delete. However, my observation is that function calls with some parameter passing causes my heap walk run to fail already. I subsequently added function calls and increasing number of parameters passed to these. My feeling was two function calls with two paramters being passed did not work anymore. However I would like to know why. Any ideas why this does not happen on some machines? Any ideas why this only happens if LowFragmentationHeap is enabled? Sample Code finally: #include <malloc.h> void staticMethodB( int a, int b ) { } void staticMethodA( int a, int b, int c) { staticMethodB( 3, 6); return; } ... _HEAPINFO hinfo; hinfo._pentry = NULL; while( ( heapstatus = _heapwalk( &hinfo ) ) == _HEAPOK ) { //doing nothing here works fine //however if i call functions here with parameters, this causes //_HEAPBADNODE or something else staticMethodA( 3,4,5); } switch( heapstatus ) { ... case _HEAPBADNODE: assert( false ); /*ERROR - bad node in heap */ break; ...

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  • Pylucene in Python 2.6 + MacOs Snow Leopard

    - by jbastos
    Greetings, I'm trying to install Pylucene on my 32-bit python running on Snow Leopard. I compiled JCC with success. But I get warnings while making pylucene: ld: warning: in build/temp.macosx-10.6-i386-2.6/build/_lucene/__init__.o, file is not of required architecture ld: warning: in build/temp.macosx-10.6-i386-2.6/build/_lucene/__wrap01__.o, file is not of required architecture ld: warning: in build/temp.macosx-10.6-i386-2.6/build/_lucene/__wrap02__.o, file is not of required architecture ld: warning: in build/temp.macosx-10.6-i386-2.6/build/_lucene/__wrap03__.o, file is not of required architecture ld: warning: in build/temp.macosx-10.6-i386-2.6/build/_lucene/functions.o, file is not of required architecture ld: warning: in build/temp.macosx-10.6-i386-2.6/build/_lucene/JArray.o, file is not of required architecture ld: warning: in build/temp.macosx-10.6-i386-2.6/build/_lucene/JObject.o, file is not of required architecture ld: warning: in build/temp.macosx-10.6-i386-2.6/build/_lucene/lucene.o, file is not of required architecture ld: warning: in build/temp.macosx-10.6-i386-2.6/build/_lucene/types.o, file is not of required architecture ld: warning: in /Developer/SDKs/MacOSX10.4u.sdk/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/JCC-2.3-py2.6-macosx-10.3-fat.egg/libjcc.dylib, file is not of required architecture ld: warning: in /Developer/SDKs/MacOSX10.4u.sdk/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/JCC-2.3-py2.6-macosx-10.3-fat.egg/libjcc.dylib, file is not of required architecture build of complete Then I try to import lucene: MacBookPro:~/tmp/trunk python Python 2.6.3 (r263:75184, Oct 2 2009, 07:56:03) [GCC 4.0.1 (Apple Inc. build 5493)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> import pylucene Traceback (most recent call last): File "<stdin>", line 1, in <module> ImportError: No module named pylucene >>> import lucene Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/lucene-2.9.0-py2.6-macosx-10.6-i386.egg/lucene/__init__.py", line 7, in <module> import _lucene ImportError: dlopen(/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/lucene-2.9.0-py2.6-macosx-10.6-i386.egg/lucene/_lucene.so, 2): Symbol not found: __Z8getVMEnvP7_object Referenced from: /Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/lucene-2.9.0-py2.6-macosx-10.6-i386.egg/lucene/_lucene.so Expected in: flat namespace in /Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/lucene-2.9.0-py2.6-macosx-10.6-i386.egg/lucene/_lucene.so >>> Any hints?

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  • Another IKImageView Question: copying a region

    - by Brian Postow
    I'm trying to use the select and copy feature of the IKImageView. If all you want to do is have an app with an image, select a portion and copy it to the clipboard, it's easy. You set the copy menu pick to the first responder's copy:(id) method and magically everything works. However, if you want something more complicated, like you want to copy as part of some other operation, I can't seem to find the method to do this. IKImageView doesn't seem to have a copy method, it doesn't seem to have a method that will even tell you the selected rectangle! I have gone through Hillegass' book, so I understand how the clipboard works, just not how to get the portion of the image out of the view... Now, I'm starting to think that I made a mistake in basing my project on IKImageView, but it's what Preview is built on (or so I've read), so I figured it had to be stable... and anyway, now it's too late, I'm too deep in this to start over... So, other than not using IKImageView, any suggestions on how to copy the select region to the clipboard manually? EDIT actually, I have found the copy(id) method, but when I call it, I get <Error>: CGBitmapContextCreate: unsupported parameter combination: 8 integer bits/component; 16 bits/pixel; 1-component color space; kCGImageAlphaPremultipliedLast; 2624 bytes/row. Which obviously doesn't happen when I do a normal copy through the first-responder... I understand the error message, but I'm not sure where it's getting those parameters from... Is there any way to trace through this and see how this is happening? A debugger won't help for obvious reasons, as well as the fact that I'm doing this in Mozilla, so a debugger isn't an option anyway... EDIT 2 It occurs to me that the copy:(id) method I found may be copying the VIEW rather than copying a chunk of the image to the clipboard, which is what I need. The reason I thought it was the clipboard copy is that in another project, where I'm copying from an IKImageView to the clipboard straight from the edit menu, it just sends a copy:(id) to the firstResponder, but I'm not actually sure what the firstresponder does with it...

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  • Is there any "modern" text editor with command-line/minibuffer?

    - by Pedro Morte Rolo
    A command line in a text editor is a wonderful feature. It allows the user to explore the editor's functionality and learn it's shortcuts in a textual way. It's much faster than using the mouse, and it is much easier to memorise "shortcuts" this way. Emacs and VI provide this, though, emacs and vi are not "modern". By "modern", I mean one that is original built to cope with the modern de-facto standards of selecting, copying, pasting, cutting, undoing, redoing and auto-completing. Cream/vi or Emacs/CUA are not valid options, since there are loads of things built over them that conflict with the mentioned stuff. It would be nice if there was an editor that would cope with the modern de-facto standards out-off-the-box, but still provide a command-line/minibuffer to perform/explore the commands and learn its shortcuts. Is there such a thing? I do not intend to use the "modern" term as derrogatory. I love both Emacs and VI, but I hate their keyboard-shortcut historical baggage. When I reffer to de-facto standards, I am not talking about Windows vs Whatever. Kate, gedit, Eclipse, Intelij or Textmate also follow the norm I am talking about and are not Windows editors. Please do not advertise Vim and Emacs, that's not answering the question. I am asking for alternatives. Why don't I like emacs and vi: Emacs: Despite CUA mode, emacs has loads of modes that conflict with this (e.g. slime, ruby-mode, etc...) It would be nice to have something that would work out-off-the-box. VI: I do not like that it is Visual/Insert-based. I do not know how to browse the text-editor's commands. I do not like that it is so much tought for the terminal. I believe that it has the same problem that I mentioned for emacs. This question is starting to look like requirement analysis.. As de-facto standards I mean: Ctrol-XCV for cut-copy-paste Ctrol-A for select-all Contrl-Z for Undo Ctrol-Y for Redo Control-F for Searching Contrl-Space for auto-complete Shift-arrow for selection Control-arrow for word-navigation Alt-Arrow for moving

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  • Multiline editable textarea in SVG

    - by Timo
    I'm trying to implement multiline editable textfield in SVG. I have the following code in http://jsfiddle.net/ca4d3/ : <svg width="1000" height="1000" overflow="scroll"> <g transform="rotate(5)"> <rect width="300" height="400" fill="#22DD22" fill-opacity="0.5"/> </g> <foreignObject x="10" y="10" overflow="visible" width="10000" height="10000" requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility"> <p style="display:table-cell;padding:10px;border:1px solid red; background-color:white;opacity:0.5;font-family:Verdana; font-size:20px;white-space: pre; word-wrap: normal; overflow: visible; overflow-y: visible; overflow-x:visible;" contentEditable="true" xmlns="http://www.w3.org/1999/xhtml"> Write here some text. Be smart and select some word. If you wanna be really COOL, paste here something cool! </p> </foreignObject> </svg> In newest Chrome, Safari and Firefox the code works in some way, but in Opera and IE 9 not. The goal is that: 0) Works in newest Chrome, Safari, Firefox, Opera and IE and if ever possible in some pads. 1) White-spaces are preserved and text wraps only on newline char (works in Chrome, Safari and Firefox, but not in Opera and IE 9 *). 2) The textfield is editable (in the same reliable and stabile way as textareas and contenteditable p elements in html) and height and width is expanded to fit text (works in Chrome, Safari and Firefox, but not in Opera and IE 9 *). 3) Texfield can be transformed (rotated, skewed, translated) while maintaining text editability (Tested rotation, but not work in any browser *). EDIT: Foreignobject rotation works on Firefox 15.0.1, but not in Safari 5.1.7 (6534.57.2), Chrome 22.0.1229.79, Opera 12.02, IE 9. Tested on Mac OS X 10.6.8. 4) Textfield can be clipped and masked while not necessarily maintaining text editability (not yet tested). *) using above code These all can be achieved using Flash, but Flash has so severe problems that it is not suitable for my purposes (after every little change in code, all have to be compiled again using Flex, which is slow, font size has limits, tracking technique is pixeloriented, not relative to em size etc.) and there still are differences across platforms. And I want to give a try to SVG! GUESTION: Can I achieve my goals 0-4 with current SVG support in browsers? Is coming SVG 2.0 for some help in this case? EDIT: Changed display:table to display:table-cell (and added new jsfiddle), because display:table made the field to loses focus when pressed arrow-up on first text row.

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  • Bracketing algorithm when root finding. Single root in "quadratic" function

    - by Ander Biguri
    I am trying to implement a root finding algorithm. I am using the hybrid Newton-Raphson algorithm found in numerical recipes that works pretty nicely. But I have a problem in bracketing the root. While implementing the root finding algorithm I realised that in several cases my functions have 1 real root and all the other imaginary (several of them, usually 6 or 9). The only root I am interested is in the real one so the problem is not there. The thing is that the function approaches the root like a cubic function, touching with the point the y=0 axis... Newton-Rapson method needs some brackets of different sign and all the bracketing methods I found don't work for this specific case. What can I do? It is pretty important to find that root in my program... EDIT: more problems: sometimes due to reaaaaaally small numerical errors, say a variation of 1e-6 in some value the "cubic" function does NOT have that real root, it is just imaginary with a neglectable imaginary part... (checked with matlab) EDIT 2: Much more information about the problem. Ok, I need root finding algorithm. Info I have: The root I need to find is between [0-1] , if there are more roots outside that part I am not interested in them. The root is real, there may be imaginary roots, but I don't want them. Probably all the rest of the roots will be imaginary The root may be double in that point, but I think that actually doesn't mater in numerical analysis problems I need to use the root finding algorithm several times during the overall calculations, but the function will always be a polynomial In one of the particular cases of the root finding, my polynomial will be similar to a quadratic function that touches Y=0 with the point. Example of a real case: The coefficient may not be 100% precise and that really slight imprecision may make the function not to touch the Y=0 axis. I cannot solve for this specific case because in other cases it may be that the polynomial is pretty normal and doesn't make any "strange" thing. The method I am actually using is NewtonRaphson hybrid, where if the derivative is really small it makes a bisection instead of NewRaph (found in numerical recipes). Matlab's answer to the function on the image: roots: 0.853553390593276 + 0.353553390593278i 0.853553390593276 - 0.353553390593278i 0.146446609406726 + 0.353553390593273i 0.146446609406726 - 0.353553390593273i 0.499999999999996 + 0.000000040142134i 0.499999999999996 - 0.000000040142134i The function is a real example I prepared where I know that the answer I want is 0.5 Note: I still haven't check completely some of the answers I you people have give me (Thank you!), I am just trying to give al the information I already have to complete the question.

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  • May volatile be in user defined types to help writing thread-safe code

    - by David Rodríguez - dribeas
    I know, it has been made quite clear in a couple of questions/answers before, that volatile is related to the visible state of the c++ memory model and not to multithreading. On the other hand, this article by Alexandrescu uses the volatile keyword not as a runtime feature but rather as a compile time check to force the compiler into failing to accept code that could be not thread safe. In the article the keyword is used more like a required_thread_safety tag than the actual intended use of volatile. Is this (ab)use of volatile appropriate? What possible gotchas may be hidden in the approach? The first thing that comes to mind is added confusion: volatile is not related to thread safety, but by lack of a better tool I could accept it. Basic simplification of the article: If you declare a variable volatile, only volatile member methods can be called on it, so the compiler will block calling code to other methods. Declaring an std::vector instance as volatile will block all uses of the class. Adding a wrapper in the shape of a locking pointer that performs a const_cast to release the volatile requirement, any access through the locking pointer will be allowed. Stealing from the article: template <typename T> class LockingPtr { public: // Constructors/destructors LockingPtr(volatile T& obj, Mutex& mtx) : pObj_(const_cast<T*>(&obj)), pMtx_(&mtx) { mtx.Lock(); } ~LockingPtr() { pMtx_->Unlock(); } // Pointer behavior T& operator*() { return *pObj_; } T* operator->() { return pObj_; } private: T* pObj_; Mutex* pMtx_; LockingPtr(const LockingPtr&); LockingPtr& operator=(const LockingPtr&); }; class SyncBuf { public: void Thread1() { LockingPtr<BufT> lpBuf(buffer_, mtx_); BufT::iterator i = lpBuf->begin(); for (; i != lpBuf->end(); ++i) { // ... use *i ... } } void Thread2(); private: typedef vector<char> BufT; volatile BufT buffer_; Mutex mtx_; // controls access to buffer_ };

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