SUPipedUnarchiver.m

//
//  SUPipedUnarchiver.m
//  Sparkle
//
//  Created by Andy Matuschak on 6/16/08.
//  Copyright 2008 Andy Matuschak. All rights reserved.
//

#import "SUPipedUnarchiver.h"
#import "SUUnarchiver_Private.h"
#import "SULog.h"


@implementation SUPipedUnarchiver

+ (SEL)selectorConformingToTypeOfPath:(NSString *)path
{
	static NSDictionary *typeSelectorDictionary;
	if (!typeSelectorDictionary)
		typeSelectorDictionary = [@{@".zip": @"extractZIP",
                                    @".tar": @"extractTAR",
								    @".tar.gz": @"extractTGZ",
                                    @".tgz": @"extractTGZ",
								    @".tar.bz2": @"extractTBZ",
                                    @".tbz": @"extractTBZ"} retain];

	NSString *lastPathComponent = [path lastPathComponent];
	for (NSString *currentType in typeSelectorDictionary)
	{
		if ([currentType length] > [lastPathComponent length]) continue;
		if ([[lastPathComponent substringFromIndex:[lastPathComponent length] - [currentType length]] isEqualToString:currentType])
			return NSSelectorFromString(typeSelectorDictionary[currentType]);
	}
	return NULL;
}

- (void)start
{
	[NSThread detachNewThreadSelector:[[self class] selectorConformingToTypeOfPath:archivePath] toTarget:self withObject:nil];
}

+ (BOOL)canUnarchivePath:(NSString *)path
{
	return ([self selectorConformingToTypeOfPath:path] != nil);
}

// This method abstracts the types that use a command line tool piping data from stdin.
- (void)extractArchivePipingDataToCommand:(NSString *)command
{
	// *** GETS CALLED ON NON-MAIN THREAD!!!
	@autoreleasepool {
		FILE *fp = NULL, *cmdFP = NULL;
		char *oldDestinationString = NULL;

		SULog(@"Extracting %@ using '%@'",archivePath,command);

		// Get the file size.
		NSNumber *fs = [[NSFileManager defaultManager] attributesOfItemAtPath:archivePath error:nil][NSFileSize];
		if (fs == nil) goto reportError;

		// Thank you, Allan Odgaard!
		// (who wrote the following extraction alg.)
		fp = fopen([archivePath fileSystemRepresentation], "r");
		if (!fp) goto reportError;

		oldDestinationString = getenv("DESTINATION");
		setenv("DESTINATION", [[archivePath stringByDeletingLastPathComponent] fileSystemRepresentation], 1);
		cmdFP = popen([command fileSystemRepresentation], "w");
		size_t written;
		if (!cmdFP) goto reportError;

		char buf[32*1024];
		size_t len;
		while((len = fread(buf, 1, 32*1024, fp)))
		{
			written = fwrite(buf, 1, len, cmdFP);
			if( written < len )
			{
				pclose(cmdFP);
				goto reportError;
			}

			dispatch_async(dispatch_get_main_queue(), ^{
				[self notifyDelegateOfExtractedLength:len];
			});
		}
		pclose(cmdFP);

		if (ferror(fp)) {
			goto reportError;
		}

		dispatch_async(dispatch_get_main_queue(), ^{
			[self notifyDelegateOfSuccess];
		});
		goto finally;

	reportError:
		dispatch_async(dispatch_get_main_queue(), ^{
			[self notifyDelegateOfFailure];
		});

	finally:
		if (fp)
			fclose(fp);
		if (oldDestinationString)
			setenv("DESTINATION", oldDestinationString, 1);
		else
			unsetenv("DESTINATION");
	}
}

- (void)extractTAR
{
	// *** GETS CALLED ON NON-MAIN THREAD!!!

	[self extractArchivePipingDataToCommand:@"tar -xC \"$DESTINATION\""];
}

- (void)extractTGZ
{
	// *** GETS CALLED ON NON-MAIN THREAD!!!

	[self extractArchivePipingDataToCommand:@"tar -zxC \"$DESTINATION\""];
}

- (void)extractTBZ
{
	// *** GETS CALLED ON NON-MAIN THREAD!!!

	[self extractArchivePipingDataToCommand:@"tar -jxC \"$DESTINATION\""];
}

- (void)extractZIP
{
	// *** GETS CALLED ON NON-MAIN THREAD!!!

	[self extractArchivePipingDataToCommand:@"ditto -x -k - \"$DESTINATION\""];
}

+ (void)load
{
	[self registerImplementation:self];
}

@end