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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