//

// QLSMagicFileAttributes.m

// QuickLookStephen

//

// Created by Nick Hutchinson on 31/07/12.

//

#import "QLSFileAttributes.h"

@interface QLSFileAttributes ()

@property (readwrite) BOOL isTextFile;

@property (readwrite) NSString *mimeType;

@property (readwrite) CFStringEncoding fileEncoding;

@property (readwrite) NSURL *url;

@end

@implementation QLSFileAttributes

+ (instancetype)attributesForItemAtURL:(NSURL *)aURL {

if ([aURL.lastPathComponent isEqualToString:@".DS_Store"]) {

NSLog(@"Ignore the .DS_Store file.");

return nil;

}

NSString *magicString = [self magicStringForItemAtURL:aURL usingLcALL:@"en_US.UTF-8"];

if (!magicString) magicString = [self magicStringForItemAtURL:aURL usingLcALL:@"C"];

if (!magicString) return nil;

NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"(\\S+/\\S+); charset=(\\S+)" options:0 error:nil];

NSTextCheckingResult *match = [regex firstMatchInString:magicString options:0 range:NSMakeRange(0, magicString.length)];

if (!match) return nil;

NSString *mimeType = [magicString substringWithRange:[match rangeAtIndex:1]];

NSString *charset = [magicString substringWithRange:[match rangeAtIndex:2]];

BOOL mimeTypeIsTextual = [self mimeTypeIsTextual:mimeType];

CFStringEncoding encoding =

CFStringConvertIANACharSetNameToEncoding((CFStringRef)charset);

QLSFileAttributes *attributes = [QLSFileAttributes new];

attributes.fileEncoding = encoding;

attributes.isTextFile = mimeTypeIsTextual;

attributes.mimeType = mimeType;

attributes.url = aURL;

return attributes;

}

////////////////////////////////////////////////////////////////////////////////

// Private Methods

////////////////////////////////////////////////////////////////////////////////

+ (NSString *)magicStringForItemAtURL:(NSURL *)aURL usingLcALL:(NSString *)lcALL {

NSString *path = [aURL path];

NSParameterAssert(path);

NSMutableDictionary *environment =

[NSProcessInfo.processInfo.environment mutableCopy];

environment[@"LC_ALL"] = lcALL;

NSTask *task = [NSTask new];

task.launchPath = @"/usr/bin/file";

task.arguments = @[@"--mime", @"--brief", path];

task.environment = environment;

task.standardOutput = [NSPipe new];

[task launch];

NSData *output =

[[task.standardOutput fileHandleForReading] readDataToEndOfFile];

[task waitUntilExit];

if (task.terminationReason != NSTaskTerminationReasonExit

|| task.terminationStatus != 0) {

return nil;

}

NSCharacterSet *whitespaceCharset =

[NSCharacterSet whitespaceAndNewlineCharacterSet];

NSString *stringOutput =

[[NSString alloc] initWithData:output encoding:NSUTF8StringEncoding];

stringOutput =

[stringOutput stringByTrimmingCharactersInSet:whitespaceCharset];

return stringOutput;

}

/**

* @return YES if mimeType contains "text", or if the mime type conforms to the

* public.text UTI.

*/

+ (BOOL)mimeTypeIsTextual:(NSString *)mimeType {

NSArray *components = [mimeType componentsSeparatedByString:@"/"];

if (components.count != 2)

return NO;

if ([components[0] rangeOfString:@"text"].location != NSNotFound)

return YES;

NSString *UTType =

CFBridgingRelease(UTTypeCreatePreferredIdentifierForTag(

kUTTagClassMIMEType,

(__bridge CFStringRef)mimeType,

kUTTypeData));

if (UTTypeConformsTo((__bridge CFStringRef)UTType, kUTTypeText)) {

return YES;

}

return NO;

}

@end