使用 Cocoa 复制任意文件的推荐方法
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【中文标题】使用 Cocoa 复制任意文件的推荐方法【英文标题】:Recommended way to copy arbitrary files using Cocoa 【发布时间】:2012-02-27 17:49:18 【问题描述】:我需要将文件从一个 OS X 卷复制到另一个 OS X 卷。虽然 *.app 严格来说不是文件而是文件夹,但用户希望它们是一个单元。因此,如果用户选择了一个文件,应用程序不应显示其文件夹的内容,而是将其作为一个单元进行复制。
因此我问,是否存在使用纯 Cocoa 代码复制文件的推荐方法。
可选:哪个命令行工具提供帮助并且可以被 Cocoa 应用程序使用。
【问题讨论】:
【参考方案1】:NSFileManager是你的朋友:
NSError *error = nil;
if ([[NSFileManager defaultManager] copyItemAtPath:@"path/to/source" toPath:@"path/to/destination" error:&error])
// copy succeeded
else
// copy failed, print error
【讨论】:
谢谢!除了这个事实:copyItemAtPath:toPath: error: aborts,如果存在某个目标文件。我应该先删除相同的目标文件吗?其他方法? @SteAp 视情况而定。您可以使用 NSFileManager 进行删除、移动等操作,因此您可以自行决定该场景的适当操作。 好的,那我没有忽略什么。另一个版本的 copyItemAtPath: with options 不存在。再次感谢!【参考方案2】:您也可以使用FSCopyObjectAsync 函数。您可以显示文件复制进度,也可以使用 FSCopyObjectAsync() 取消文件复制。 看看FSFileOperation 示例代码。
此示例展示了如何复制和移动文件和文件夹。它 显示了同步和异步(使用 CFRunLoop)的使用 FSFileOperation API。此外,它还显示路径和 FSRef API 的变体以及如何从回调中获取状态。这 API 在概念上类似于引入的 FSVolumeOperation API 在 Mac OS X 10.2 中。
FSCopyObjectAsync 示例:
#import <Cocoa/Cocoa.h>
@interface AsyncCopyController : NSObject
-(OSStatus)copySource : (NSString *)aSource ToDestination: (NSString *)aDestDir setDelegate : (id)object;
//delegate method
-(void)didReceiveCurrentPath : (NSString *)curremtItemPath bytesCompleted : (unsigned long long)floatBytesCompleted currentStageOfFileOperation : (unsigned long)stage;
-(void)didCopyOperationComplete : (BOOL)boolean;
-(void)didReceiveCopyError : (NSString *)Error;
-(void)cancelAllAsyncCopyOperation;
@end
#import "AsyncCopyController.h"
static Boolean copying= YES;
@implementation AsyncCopyController
static void statusCallback (FSFileOperationRef fileOp,
const FSRef *currentItem,
FSFileOperationStage stage,
OSStatus error,
CFDictionaryRef statusDictionary,
void *info )
NSLog(@"Callback got called. %ld", error);
id delegate;
if (info)
delegate = (id)info;
if (error!=0)
if (error==-48)
[delegate didReceiveCopyError:@"Duplicate filename and version or Destination file already exists or File found instead of folder"];
CFURLRef theURL = CFURLCreateFromFSRef( kCFAllocatorDefault, currentItem );
NSString* currentPath = [(NSURL *)theURL path];
// NSLog(@"currentPath %@", currentPath);
// If the status dictionary is valid, we can grab the current values to
// display status changes, or in our case to update the progress indicator.
if (statusDictionary)
CFNumberRef bytesCompleted;
bytesCompleted = (CFNumberRef) CFDictionaryGetValue(statusDictionary,
kFSOperationBytesCompleteKey);
CGFloat floatBytesCompleted;
CFNumberGetValue (bytesCompleted, kCFNumberMaxType,
&floatBytesCompleted);
// NSLog(@"Copied %d bytes so far.",
// (unsigned long long)floatBytesCompleted);
if (info)
[delegate didReceiveCurrentPath :currentPath bytesCompleted :floatBytesCompleted currentStageOfFileOperation:stage];
NSLog(@"stage %d", stage);
if (stage == kFSOperationStageComplete)
NSLog(@"Finished copying the file");
if (info)
[delegate didCopyOperationComplete:YES];
// Would like to call a Cocoa Method here...
if (!copying)
FSFileOperationCancel(fileOp);
-(void)cancelAllAsyncCopyOperation
copying = NO;
-(OSStatus)copySource : (NSString *)aSource ToDestination: (NSString *)aDestDir setDelegate : (id)object
NSLog(@"copySource");
copying = YES;
CFRunLoopRef runLoop = CFRunLoopGetCurrent();
NSLog(@"%@", runLoop);
FSFileOperationRef fileOp = FSFileOperationCreate(kCFAllocatorDefault);
require(fileOp, FSFileOperationCreateFailed);
OSStatus status = FSFileOperationScheduleWithRunLoop(fileOp,
runLoop, kCFRunLoopDefaultMode);
if (status)
NSLog(@"Failed to schedule operation with run loop: %@", status);
return status;
require_noerr(status, FSFileOperationScheduleWithRunLoopFailed);
if (status)
NSLog(@"Failed to schedule operation with run loop: %@", status);
//return NO;
// Create a filesystem ref structure for the source and destination and
// populate them with their respective paths from our NSTextFields.
FSRef source;
FSRef destination;
// Used FSPathMakeRefWithOptions instead of FSPathMakeRef
// because I needed to use the kFSPathMakeRefDefaultOptions
// to deal with file paths to remote folders via a /Volume reference
status = FSPathMakeRefWithOptions((const UInt8 *)[aSource fileSystemRepresentation],
kFSPathMakeRefDefaultOptions,
&source,
NULL);
require_noerr(status, FSPathMakeRefWithOptionsaSourceFailed);
Boolean isDir = true;
status = FSPathMakeRefWithOptions((const UInt8 *)[aDestDir fileSystemRepresentation],
kFSPathMakeRefDefaultOptions,
&destination,
&isDir);
require_noerr(status, FSPathMakeRefWithOptionsaDestDirFailed);
// Needed to change from the original to use CFStringRef so I could convert
// from an NSString (aDestFile) to a CFStringRef (targetFilename)
FSFileOperationClientContext clientContext;
// The FSFileOperation will copy the data from the passed in clientContext so using
// a stack based record that goes out of scope during the operation is fine.
if (object)
clientContext.version = 0;
clientContext.info = (void *) object;
clientContext.retain = CFRetain;
clientContext.release = CFRelease;
clientContext.copyDescription = CFCopyDescription;
// Start the async copy.
status = FSCopyObjectAsync (fileOp,
&source,
&destination, // Full path to destination dir
NULL,// Use the same filename as source
kFSFileOperationDefaultOptions,
statusCallback,
1.0,
object != NULL ? &clientContext : NULL);
//CFRelease(fileOp);
NSLog(@"Failed to begin asynchronous object copy: %d", status);
if (status)
NSString * errMsg = [NSString stringWithFormat:@" - %@", status];
NSLog(@"Failed to begin asynchronous object copy: %d", status);
if (object)
[object release];
FSFileOperationScheduleWithRunLoopFailed:
CFRelease(fileOp);
FSPathMakeRefWithOptionsaSourceFailed:
FSPathMakeRefWithOptionsaDestDirFailed:
FSFileOperationCreateFailed:
return status;
@end
FSCopyObjectAsync 在 OS X v10.8 中已弃用
copyfile(3) 是 FSCopyObjectAsync 的替代方案。 Here 是带有进度回调的 copyfile(3) 示例。
【讨论】:
FSCopyObjectAsync 未被弃用。 不,绝对不是。但是还没有看到如此大量的参考...... 看看this的实现。 感谢您的出色回答。你在头文件中声明的其他方法中做了什么?像 didReceiveCurrentPath?想要实现这个只是想确保我没有错过任何东西。谢谢 @Fabiosoft 也许***.com/questions/10414802/… 会有所帮助。以上是关于使用 Cocoa 复制任意文件的推荐方法的主要内容,如果未能解决你的问题,请参考以下文章
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