iOS array not being filled completely - iphone

Question

I am using these two recursive methods to find the paths of files and directories in a certain folder
- (NSMutableArray *)getFilePathsFromDirectory:(NSString *)directory{
NSMutableArray *contents = [[NSMutableArray alloc] init];
NSArray *arr = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:directory error:nil];
for (NSString *file in arr) {
BOOL isDir;
[[NSFileManager defaultManager] fileExistsAtPath:[directory stringByAppendingPathComponent:file] isDirectory:&isDir];
if (!isDir) {
[contents addObject:[directory stringByAppendingPathComponent:file]];
}
else{
[contents addObject:[directory stringByAppendingPathComponent:file]];
[contents addObject:[self getFilePathsFromDirectory:[directory stringByAppendingPathComponent:file]]];
}
}
return contents;
}
- (NSString *)getPathForItemNamed:(NSString *)name array:(NSMutableArray *)arr{
NSString *str;
if (name) {
for (NSString *s in arr) {
if ([s isKindOfClass:[NSString class]]) {
if ([[s lastPathComponent] isEqualToString:name]) {
return s;
}
}
}
for (NSMutableArray *aq in arr) {
if ([aq isKindOfClass:[NSMutableArray class]]) {
str = [self getPathForItemNamed:name array:aq];
return str;
}
}
}
return str;
}
but the problem is, after going through a certain amount of subdirectories (3-5), this stops returning any path and returns (null). I feel like this has to do with the array not being filled with all the directories before it returns for some reason. Heres how I call these
NSMutableArray *paths = [self getContentsOfPaths:[self downloadsDir]];
path = [self getPathForItemNamed:[tableView cellForRowAtIndexPath:indexPath].textLabel.text array:paths];
NSLog(#"%#", path);

Answer 1

There are two problems with your getPathForItemNamed: method:
When it cannot find a file by name, it returns a value of an uninitialized variable str. This is undefined behavior - you need to set str to nil upon initialization. In fact, you do not need str at all (see the fix below).
When it discovers its first subdirectory, it assumes that the file that it is looking for must be inside that subdirectory, even if it is not. Whatever the first-level recursive invocation of getPathForItemNamed: returns, becomes the return result of the top-level invocation. This is bad: if the file that you are looking for is in the subtree of the second subdirectory, you are never going to find it!
Here is how you can fix your method:
- (NSString *)getPathForItemNamed:(NSString *)name array:(NSMutableArray *)arr{
if (!name) return nil;
for (NSString *s in arr) {
if ([s isKindOfClass:[NSString class]]) {
if ([[s lastPathComponent] isEqualToString:name]) {
return s;
}
}
}
for (NSMutableArray *aq in arr) {
if ([aq isKindOfClass:[NSMutableArray class]]) {
str = [self getPathForItemNamed:name array:aq];
// Return something only when you find something
if (str) return str;
}
}
return nil; // You do not need str at all.
}