Ben, thank you so much! I have successfully done it.
I post the code here for anyone to use it. I love this list.
- (NSData*)UnzipFile:(NSString*)sourcePath
extractFileName:(NSString*)extractFileName
{
NSTask *unzip = [[[NSTask alloc] init] autorelease];
NSPipe *aPipe = [NSPipe pipe];
[unzip setStandardOutput:aPipe];
[unzip setLaunchPath:@"/usr/bin/unzip"];
[unzip setArguments:[NSArray arrayWithObjects:@"-p", sourcePath,
extractFileName, nil]];
[unzip launch];
NSMutableData *dataOut = [NSMutableData data];
NSData *dataIn = nil;
NSException *error = nil;
while((dataIn = [[aPipe fileHandleForReading]
availableDataOrError:&error]) && [dataIn length] && error == nil){
[dataOut appendData:dataIn];
}
if([dataOut length] && error == nil){
return dataOut;
}
return nil;
}
// Then I subclassed NSFileHandler this way
@implementation NSFileHandle (MyOwnAdditions)
- (NSData*)availableDataOrError:(NSException**)returnError
{
for(;;){
@try{
return [self availableData];
}...@catch (NSException *e) {
if ([[e name] isEqualToString:NSFileHandleOperationException]) {
if ([[e reason] isEqualToString:@"*** -[NSConcreteFileHandle
availableData]: Interrupted system call"]) {
continue;
}
if (returnError)
*returnError = e;
return nil;
}
@throw;
}
}
}
@end
> Da: Ben Haller <bhcocoa...@sticksoftware.com>
> Data: Sat, 27 Nov 2010 12:12:39 -0500
> A: Dave DeLong <davedel...@me.com>
> Cc: "gMail.com" <mac.iphone....@gmail.com>, Cocoa List
> <cocoa-dev@lists.apple.com>
> Oggetto: Re: NSTask with unzip
>
> Here's a post that I found useful:
>
> http://dev.notoptimal.net/2007/04/nstasks-nspipes-and-deadlocks-when.html
>
> Dave, not sure what you mean here. NSPipe uses NSFileHandle. Does using an
> NSFileHandle directly change things somehow? If so, why? I think this is an
> avenue I haven't explored; once I (finally) figured out the right magic
> incantations to get things to work reliably with NSPipe, I now recycle that
> code everywhere I need an NSTask :->.
>
> Ben Haller
> McGill University
>
>
> On 2010-11-27, at 11:48 AM, Dave DeLong wrote:
>
>> The way I get around this is to use an NSFileHandle for standard out instead
>> of an NSPipe. It's a bit less efficient, but slightly more convenient.
>>
>> Dave
>>
>> Sent from my iPhone
>>
>> On Nov 27, 2010, at 7:59 AM, Ben Haller <bhcocoa...@sticksoftware.com> wrote:
>>
>>> On 2010-11-26, at 7:33 AM, gMail.com wrote:
>>>
>>>> Hi, I can properly unzip a zip file launching a NSTask with /usr/bin/unzip
>>>> The task saves the unzipped file to the disk, then a I read the unzipped
>>>> file in a NSData. Well. My question is:
>>>> Can I do the same job without saving the unzipped file to the disk?
>>>>
>>>> I have tried to set the standard output to a pipe - which works well with
>>>> other tasks - but here it doesn't work. The task never exits. Here's the
>>>> wrong code:
>>>>
>>>> NSTask *unzip = [[[NSTask alloc] init] autorelease];
>>>> [unzip setLaunchPath:@"/usr/bin/unzip"];
>>>> [unzip setArguments:[NSArray arrayWithObjects:@"-p", zipfile,
>>>> @"filetounzip", nil]];
>>>>
>>>> NSPipe *aPipe = [NSPipe pipe];
>>>> [unzip setStandardOutput:aPipe];
>>>> [unzip launch];
>>>> [unzip waitUntilExit];
>>>>
>>>> if([unzip terminationStatus] == noErr){
>>>> dictData = [NSMutableData data];
>>>> while((dataOut = [aPipe availableData]) && [dataOut length]){
>>>> [dictData appendData:dataOut];
>>>> }
>>>> }
>>>
>>> If I recall correctly, the problem is likely to be your use of
>>> -waitUntilExit. That API should apparently have a large red label on it
>>> ("Warnin', lark's vomit!") since everybody wants to use it this way. The
>>> problem is that the task's output pipe fills up because it isn't being
>>> serviced, and then things get locked up. You need to go with asynchronous
>>> reads to service the pipe as output gets stuffed into it. There should be
>>> lots of examples of this on this list, now that you know what to look for.
>>>
>>> What would be great would be a new call, along the lines of
>>> -dataFromWaitingUntilExit or some such, that does all this for you, since
>>> this is so commonly what people want to do.
>>>
>>> Ben Haller
>>> McGill University
>>>
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