Ojbect-C2 6、NSFileHandle 和NSFileManager 的使用

Tasks

Getting a File Handle

• + fileHandleForReadingAtPath:
• + fileHandleForReadingFromURL:error:
• + fileHandleForWritingAtPath:
• + fileHandleForWritingToURL:error:
• + fileHandleForUpdatingAtPath:
• + fileHandleForUpdatingURL:error:
• + fileHandleWithStandardError
• + fileHandleWithStandardInput
• + fileHandleWithStandardOutput
• + fileHandleWithNullDevice

Creating a File Handle

• – initWithFileDescriptor:
• – initWithFileDescriptor:closeOnDealloc:

Getting a File Descriptor

• – fileDescriptor

Reading from a File Handle

• – availableData
• – readDataToEndOfFile
• – readDataOfLength:

Writing to a File Handle

• – writeData:

Reading and Writing Using Blocks

•    readabilityHandler  property
•    writeabilityHandler  property

Communicating Asynchronously

• – acceptConnectionInBackgroundAndNotify
• – acceptConnectionInBackgroundAndNotifyForModes:
• – readInBackgroundAndNotify
• – readInBackgroundAndNotifyForModes:
• – readToEndOfFileInBackgroundAndNotify
• – readToEndOfFileInBackgroundAndNotifyForModes:
• – waitForDataInBackgroundAndNotify
• – waitForDataInBackgroundAndNotifyForModes:

Seeking Within a File

• – offsetInFile
• – seekToEndOfFile
• – seekToFileOffset:

Operating on a File

• – closeFile
• – synchronizeFile
• – truncateFileAtOffset:

Properties

readabilityHandler

The block to use for reading the contents of the file handle asynchronously.

@property (copy) void (^readabilityHandler)( NSFileHandle *);

Discussion

The default value of this property is nil. Assigning a valid block object to this property creates a dispatch source for reading the contents of the file or socket. Your block is submitted to the file handle’s dispatch queue when there is data to read. When reading a file, your handler block is typically executed repeatedly until the entire contents of the file have been read. When reading data from a socket, your handler block is executed whenever there is data on the socket waiting to be read.

The block you provide must accept a single parameter that is the current file handle. The return type of your block should be void.

To stop reading the file or socket, set the value of this property to nil. Doing so cancels the dispatch source and cleans up the file handle’s structures appropriately.

Availability

• Available in OS X v10.7 and later.

Declared In

NSFileHandle.h

writeabilityHandler

The block to use for writing the contents of the file handle asynchronously.

@property (copy) void (^writeabilityHandler)( NSFileHandle *);

Discussion

The default value of this property is nil. Assigning a valid block object to this property creates a dispatch source for writing the contents of the file or socket. Your block is submitted to the file handle’s dispatch queue when there is room available to write more data. When writing a file, your handler block is typically executed repeatedly until the entire contents of the file have been written. When writing data to a socket, your handler block is executed whenever the socket is ready to accept more data.

The block you provide must accept a single parameter that is the current file handle. The return type of your block should be void.

To stop writing data to the file or socket, set the value of this property to nil. Doing so cancels the dispatch source and cleans up the file handle’s structures appropriately.

Availability

• Available in OS X v10.7 and later.

Declared In

NSFileHandle.h



















NSFILEMANAGER

Tasks

Creating a File Manager

• – init
• + defaultManager

Locating System Directories

• – URLForDirectory:inDomain:appropriateForURL:create:error:
• – URLsForDirectory:inDomains:

Locating Application Group Container Directories

• – containerURLForSecurityApplicationGroupIdentifier:

Discovering Directory Contents

• – contentsOfDirectoryAtURL:includingPropertiesForKeys:options:error:
• – contentsOfDirectoryAtPath:error:
• – enumeratorAtURL:includingPropertiesForKeys:options:errorHandler:
• – enumeratorAtPath:
• – mountedVolumeURLsIncludingResourceValuesForKeys:options:
• – subpathsOfDirectoryAtPath:error:
• – subpathsAtPath:

Creating and Deleting Items

• – createDirectoryAtURL:withIntermediateDirectories:attributes:error:
• – createDirectoryAtPath:withIntermediateDirectories:attributes:error:
• – createFileAtPath:contents:attributes:
• – removeItemAtURL:error:
• – removeItemAtPath:error:
• – replaceItemAtURL:withItemAtURL:backupItemName:options:resultingItemURL:error:
• – trashItemAtURL:resultingItemURL:error:

Moving and Copying Items

• – copyItemAtURL:toURL:error:
• – copyItemAtPath:toPath:error:
• – moveItemAtURL:toURL:error:
• – moveItemAtPath:toPath:error:

Managing ICloud-Based Items

• – ubiquityIdentityToken
• – URLForUbiquityContainerIdentifier:
• – isUbiquitousItemAtURL:
• – setUbiquitous:itemAtURL:destinationURL:error:
• – startDownloadingUbiquitousItemAtURL:error:
• – evictUbiquitousItemAtURL:error:
• – URLForPublishingUbiquitousItemAtURL:expirationDate:error:

Creating Symbolic and Hard Links

• – createSymbolicLinkAtURL:withDestinationURL:error:
• – createSymbolicLinkAtPath:withDestinationPath:error:
• – linkItemAtURL:toURL:error:
• – linkItemAtPath:toPath:error:
• – destinationOfSymbolicLinkAtPath:error:

Determining Access to Files

• – fileExistsAtPath:
• – fileExistsAtPath:isDirectory:
• – isReadableFileAtPath:
• – isWritableFileAtPath:
• – isExecutableFileAtPath:
• – isDeletableFileAtPath:

Getting and Setting Attributes

• – componentsToDisplayForPath:
• – displayNameAtPath:
• – attributesOfItemAtPath:error:
• – attributesOfFileSystemForPath:error:
• – setAttributes:ofItemAtPath:error:

Getting and Comparing File Contents

• – contentsAtPath:
• – contentsEqualAtPath:andPath:

Converting File Paths to Strings

• – fileSystemRepresentationWithPath:
• – stringWithFileSystemRepresentation:length:

Managing the Delegate

• – setDelegate:
• – delegate

Managing the Current Directory

• – changeCurrentDirectoryPath:
• – currentDirectoryPath

Deprecated Methods

• – changeFileAttributes:atPath: Deprecated in OS X v10.5
• – copyPath:toPath:handler: Deprecated in OS X v10.5
• – createDirectoryAtPath:attributes: Deprecated in OS X v10.5
• – createSymbolicLinkAtPath:pathContent: Deprecated in OS X v10.5
• – directoryContentsAtPath: Deprecated in OS X v10.5
• – fileAttributesAtPath:traverseLink: Deprecated in OS X v10.5
• – fileSystemAttributesAtPath: Deprecated in OS X v10.5
• – linkPath:toPath:handler: Deprecated in OS X v10.5
• – movePath:toPath:handler: Deprecated in OS X v10.5
• – pathContentOfSymbolicLinkAtPath: Deprecated in OS X v10.5
• – removeFileAtPath:handler: Deprecated in OS X v10.5
• – fileManager:shouldProceedAfterError:  delegate method Deprecated in OS X v10.5
• – fileManager:willProcessPath:  delegate method Deprecated in OS X v10.5