What's the least resource intensive way to find out if an object is a folder?
I need to sort 8145 objects (there may be more) for files and folders. (Tested on A8X).
First method.
for(NSString *filename in FilesList) //This method takes an average of 7.7 seconds.
{
fileExtension = (__bridge CFStringRef)[filename pathExtension];
fileUTI = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, fileExtension, NULL);
if ([[[[NSFileManager defaultManager] attributesOfItemAtPath:[FolderPath stringByAppendingPathComponent:filename] error:nil] fileType] isEqualToString:@"NSFileTypeDirectory"] && !UTTypeConformsTo(fileUTI, kUTTypeRTFD))
[OnlyFolderList addObject:filename];
else
[OnlyFilesList addObject:filename];
}
Second method.
for(NSString *filename in FilesList) //This method takes an average of 2.9 seconds.
{
fileExtension = (__bridge CFStringRef)[filename pathExtension];
fileUTI = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, fileExtension, NULL);
[[NSFileManager defaultManager] fileExistsAtPath:[FolderPath stringByAppendingPathComponent:filename] isDirectory:&isDir];
if (isDir && !UTTypeConformsTo(fileUTI, kUTTypeRTFD))
[OnlyFolderList addObject:filename];
else
[OnlyFilesList addObject:filename];
}
Do you know a faster way?
----- Updated with the fastest method ----- //0.26 seconds for 8145 objects!
NSNumber *isDirectory;
NSError *error = nil;
NSString *name;
NSArray *FilesList = [[NSFileManager defaultManager] contentsOfDirectoryAtURL:[NSURL fileURLWithPath:FolderPath] includingPropertiesForKeys:[NSArray arrayWithObjects:NSURLIsDirectoryKey,NSURLNameKey,nil] options:NSDirectoryEnumerationSkipsHiddenFiles error:nil];
for (NSURL *url in FilesList)
{
[url getResourceValue:&name forKey:NSURLNameKey error:&error];
[url getResourceValue:&isDirectory forKey:NSURLIsDirectoryKey error:&error];
if ([isDirectory boolValue])
{
CFStringRef fileExtension = (__bridge CFStringRef)[name pathExtension];
CFStringRef fileUTI = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, fileExtension, NULL);
if (!UTTypeConformsTo(fileUTI, kUTTypeRTFD))
[OnlyFolderList addObject:name];
else
[OnlyFilesList addObject:name];
}
else
[OnlyFilesList addObject:name];
}
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3 answers
Try using contentsOfDirectoryAtURL:includingPropertiesForKeys:options:error:
:
NSURL *root = ... // the root URL to get the file list from
NSFileManager *fm = [NSFileManager defaultManager];
NSError *error = nil;
NSArray *filesList = [fm contentsOfDirectoryAtURL:root includingPropertiesForKeys:@[ NSURLIsDirectoryKey, NSURLTypeIdentifierKey ] options:NSDirectoryEnumerationSkipsHiddenFiles error:&error];
if (dirURLs) {
for (NSURL *fileURL in filesList) {
NSString *filename = [[fileURL path] lastPathComponent];
NSNumber *isDir = nil;
[fileURL getResourceValue:&isDir forKey:NSURLIsDirectoryKey error:nil]
if ([isDir boolValue]) {
NSString *uti;
[fileURL getResourceValue:&uti forKey:NSURLTypeIdentifierKey error:nil];
if ([(__bridge NSString *)kUTTypeRTFD isEqualToString:uti]) {
[OnlyFilesList addObject:filename];
} else {
[OnlyFoldersList addObject:filename];
}
} else {
[OnlyFilesList addObject:filename];
}
}
} else {
NSLog(@"Unable to get list of files in %@: %@", root, error);
}
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In the second method, move the Extension and fileUTI inside the test for isDir so that the code won't run if the file is not potentially a directory.
Try the following:
NSFileManager *fileManager = [NSFileManager defaultManager];
for(NSString *filename in FilesList) {
[fileManager fileExistsAtPath:[FolderPath stringByAppendingPathComponent:filename] isDirectory:&isDir];
if (isDir) {
CFStringRef fileExtension = (__bridge CFStringRef)[filename pathExtension];
CFStringRef fileUTI = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, fileExtension, NULL);
if (!UTTypeConformsTo(fileUTI, kUTTypeRTFD))
[OnlyFolderList addObject:filename];
else
[OnlyFilesList addObject:filename];
}
else
[OnlyFilesList addObject:filename];
}
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Try to use BSD API directly.
static BOOL cStringHasSuffix(const char *string, const char *suffix) {
unsigned long stringLength = strlen(string);
unsigned long suffixLength = strlen(suffix);
return stringLength >= suffixLength && memcmp(string + stringLength - suffixLength, suffix, suffixLength) == 0;
}
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
NSURL *url = [[NSBundle mainBundle] bundleURL];
NSMutableArray *folderNames = [NSMutableArray array];
NSMutableArray *fileNames = [NSMutableArray array];
const char *rtfdSuffix = ".rtfd";
DIR *dir = opendir(url.fileSystemRepresentation);
struct dirent *item;
while ((item = readdir(dir))) {
NSString *name = [NSString stringWithUTF8String:item->d_name];
if (item->d_type == 0) {
NSLog(@"unknown type for %@", name);
} else if (item->d_type == DT_DIR) {
if (cStringHasSuffix(item->d_name, rtfdSuffix)) {
[fileNames addObject:name];
} else {
[folderNames addObject:name];
}
} else if (item->d_type == DT_REG) {
[fileNames addObject:name];
} else {
NSLog(@"unexpected type %d for %@", item->d_type, name);
}
}
closedir(dir);
NSLog(@"fileNames = %@", fileNames);
NSLog(@"folderNames = %@", folderNames);
return YES;
}
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