checks missing files (bad “Location” field) in “iTunes Music Library.xml” file.

main.m

// -*- mode: objc; coding: utf-8 -*-

#import <Foundation/Foundation.h>

static NSString *nvl(NSString *s1, NSString *s2)
{
    return s1? s1: s2;
}

@interface Parser: NSObject <NSXMLParserDelegate>
- (void)parse:(NSURL *)url;
@end

@implementation Parser
{
    int _depth;                      // <dict> のネスト度合い
    int _targetDepth;
    BOOL _shouldStore;
    NSString *_keyName;
    NSString *_prevElementName;
    NSMutableString *_buf;
    NSMutableDictionary *_track;

    int _numTracks;
    NSMutableArray *_missedTracks;
}

static NSCharacterSet *digitCharSet;

+ (void)initialize
{
    digitCharSet = [NSCharacterSet characterSetWithCharactersInString:@"0123456789"];
}

+ (BOOL)isDigit:(NSString *)text
{
    NSScanner *scanner = [NSScanner localizedScannerWithString:text];
    [scanner setCharactersToBeSkipped:nil];
    return [scanner scanCharactersFromSet:digitCharSet intoString:NULL] && [scanner isAtEnd];
}

- (void)parse:(NSURL *)url
{
    NSXMLParser *parser = [[NSXMLParser alloc] initWithContentsOfURL:url];
    parser.delegate = self;
    [parser parse];
}

- (void)parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError
{
    NSLog(@"Error: %ld, Column: %ld, Line: %ld, Description: %@",
        [parseError code],
        [parser columnNumber],
        [parser lineNumber],
        [parseError description]);
}

- (void)parserDidStartDocument:(NSXMLParser *)parser
{
    _keyName = nil;
    _prevElementName = nil;
    _shouldStore = NO;
    _depth = 0;
    _targetDepth = 0;
    _buf = [NSMutableString new];
    _track = [NSMutableDictionary new];
    _missedTracks = [NSMutableArray new];
}

- (void)parserDidEndDocument:(NSXMLParser *)parser
{
    printf("%7d tracks\n", _numTracks);
    printf("%7ld missed tracks\n", [_missedTracks count]);
    for (NSArray *info in _missedTracks) {
        printf(
            "  %s: %s\n",
            [[info objectAtIndex:0] cStringUsingEncoding:NSUTF8StringEncoding],
            [[info objectAtIndex:1] cStringUsingEncoding:NSUTF8StringEncoding]);
    }
}

- (void)store
{
    ++_numTracks;

    NSString *trackType = [_track objectForKey:@"Track Type"];
    if ([trackType isEqualToString:@"Remote"]) {
        return; // Remote Track は Location を持たない
    }
    if ([trackType isEqualToString:@"URL"]) {
        return; // URL Track は Location を持つが存在確認を行なわないことにする
    }

    NSString *trackId = [_track objectForKey:@"Track ID"];
    NSString *name = [_track objectForKey:@"Name"];
    NSString *location = [_track objectForKey:@"Location"];
    NSURL *url = [NSURL URLWithString:location];
    NSString *path = url.path;
    if (![[NSFileManager defaultManager] isReadableFileAtPath:path]) {
        [_missedTracks addObject:@[nvl(trackId, @"<>"), nvl(path, nvl(name, @"[]"))]];
    }
}

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qualifiedName attributes:(NSDictionary *)attributeDict
{
    if ([@"dict" isEqualToString:elementName]) {
        ++_depth;
        if ([@"key" isEqualToString:_prevElementName] && [Parser isDigit:_keyName]) {
            _targetDepth = _depth;
            //NSLog(@"Track ID: %@ parsing...", _keyName);
        }
    }

    _shouldStore = 0 < _depth && _targetDepth == _depth;
    [_buf setString:@""];
}

- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName
{
    if ([@"key" isEqualToString:elementName])
    {
        _keyName = [_buf copy];
    }
    else if ([@"dict" isEqualToString:elementName])
    {
        --_depth;
        if (_shouldStore) {
            _shouldStore = NO;
            _targetDepth = 0;
            [self store];
            [_track removeAllObjects];
        }
    }
    else if (_shouldStore && [@"key" isEqualToString:_prevElementName])
    {
        NSString *value = [NSString stringWithString:_buf];
        [_track setObject:value forKey:_keyName];
    }
    _prevElementName = [elementName copy];
}

- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string
{
    [_buf appendString:string];
}

@end

void doit(NSString *path)
{
    NSDate *startTime = [NSDate date];
    [[Parser new] parse:[NSURL fileURLWithPath:path]];
    NSLog(@"XML parse time is %lf (sec)", [[NSDate date] timeIntervalSinceDate:startTime]);
}

int main(int argc, char **argv)
{
    if (argc != 2)
    {
        printf("usage: %s: itunes_library.xml\n", argv[0]);
        return 1;
    }

    @autoreleasepool
    {
        doit([NSString stringWithUTF8String:argv[1]]);
    }
    return 0;
}

Makefile

TARGET = main
OBJS = main.o

CC = clang
CFLAGS = -fobjc-arc -O2 -Wall
LDFLAGS = -framework Foundation

.m.o:
  $(CC) $(CFLAGS) -c $< -o $*.o

.PHONY: all
all: $(OBJS)
	$(CC) $(LDFLAGS) $(CFLAGS) -o $(TARGET) $(OBJS)

.PHONY: clean
clean:
	$(RM) $(TARGET) $(OBJS)

ううむ, 微妙だ…….