Hi,

I've been spending the last few hours trying to find the memory leak in my code. Here it is:

NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

expression = [expression stringByTrimmingCharactersInSet:
              [NSCharacterSet whitespaceAndNewlineCharacterSet]]; // expression is an NSString object.

NSArray *arguments = [NSArray arrayWithObjects:expression, [@"~/Desktop/file.txt" stringByExpandingTildeInPath], @"-n", @"--line-number", nil];
NSPipe *outPipe = [[NSPipe alloc] init];

NSTask *task = [[NSTask alloc] init];
[task setLaunchPath:@"/usr/bin/grep"];
[task setArguments:arguments];
[task setStandardOutput:outPipe];
[outPipe release];

[task launch];

NSData *data = [[outPipe fileHandleForReading] readDataToEndOfFile];

[task waitUntilExit];
[task release];

NSString *string = [[NSString alloc] initWithBytes:[data bytes] length:[data length] encoding:NSUTF8StringEncoding];
string = [string stringByReplacingOccurrencesOfString:@"\r" withString:@""];

int linesNum = 0;

NSMutableArray *possibleMatches = [[NSMutableArray alloc] init];

if ([string length] > 0) {

    NSArray *lines = [string componentsSeparatedByString:@"\n"];
    linesNum = [lines count];

    for (int i = 0; i < [lines count]; i++) {

        NSString *currentLine = [lines objectAtIndex:i];
        NSArray *values = [currentLine componentsSeparatedByString:@"\t"];

        if ([values count] == 20)
            [possibleMatches addObject:currentLine];
    }
}
[string release];
[pool release];

return [possibleMatches autorelease];

I tried to follow the few basic rules of Cocoa memory management, but somehow there still seems to be a leak, I believe it's an array that's leaking. It's noticeable if possibleMatches is large. You can try the code by using any large file as "~/Desktop/file.txt" and as expression something that yields many results when grep-ing.

What's the mistake I'm making?

Thanks for any help!

-- Ry