如何在 Mac 上检查文件是否为别名?到目前为止,这是我的代码:
public func getFiles(){
let folderPath = "/Users/timeBro/Desktop/testfolder"
let fileManager = NSFileManager.defaultManager()
let enumerator:NSDirectoryEnumerator = fileManager.enumeratorAtPath(folderPath)!
for url in enumerator.allObjects {
let newurl = NSURL(string: url as! String)
print("\(url as! String)")
print(url);
print(newurl?.isFileReferenceURL())
}
}
如何检查文件是否是别名?
有一个简单的解决方案,完全不需要任何指针处理:
extension URL {
func isAlias() -> Bool? {
let values = try? url.resourceValues(forKeys: [.isSymbolicLinkKey, .isAliasFileKey])
let alias = values?.isAliasFile
let symbolic = values?.isSymbolicLink
guard alias != nil, symbolic != nil else { return nil }
if alias! && !symbolic! {
return true
}
return false
}
}
说明:对于符号链接,
resourceValues(forKeys:)
返回.isAliasFile
和.isSymbolicLink
,因此在检查别名时必须确保前者返回而后者不返回。
如果路径不存在,函数返回 nil。
更新:我最初错误地认为唯一的选择是使用CoreFoundation(C API)方法,但这实际上不是真的(谢谢):Foundation(ObjC API)类
NSURL
确实如此提供一种检测 Finder 别名的方法:
// OSX 10.9+
// Indicates if the specified filesystem path is a Finder alias.
// Returns an optional Boolean: if the lookup failed, such when the path doesn't exist,
// nil is returned.
// Example: isFinderAlias("/path/to/an/alias")
func isFinderAlias(path:String) -> Bool? {
let aliasUrl = NSURL(fileURLWithPath: path)
var isAlias:AnyObject? = nil
do {
try aliasUrl.getResourceValue(&isAlias, forKey: NSURLIsAliasFileKey)
} catch _ {}
return isAlias as! Bool?
}
[不推荐,除非作为使用
UnsafeMutablePointer<Void>
的练习]IsAliasFile()
在 OS X 10.4 中已弃用,FSIsAliasFile()
继承,它在 10.8 中已弃用。CFURLCopyResourcePropertyForKey()
,这在 Swift 中处理起来并不有趣,因为必须使用 UnsafeMutablePointer<Void>
进行手动内存管理。我希望我的内存管理是正确的:
import Foundation
// Indicates if the specified filesystem path is a Finder alias.
// Returns an optional Boolean: if the lookup failed, such when the path
// doesn't exist, nil is returned.
// Example: isFinderAlias("/path/to/an/alias")
func isFinderAlias(path:String) -> Bool? {
var isAlias:Bool? = nil // Initialize result var.
// Create a CFURL instance for the given filesystem path.
// This should never fail, because the existence isn't verified at this point.
// Note: No need to call CFRelease(fUrl) later, because Swift auto-memory-manages CoreFoundation objects.
let fUrl = CFURLCreateWithFileSystemPath(nil, path, CFURLPathStyle.CFURLPOSIXPathStyle, false)
// Allocate void pointer - no need for initialization,
// it will be assigned to by CFURLCopyResourcePropertyForKey() below.
let ptrPropVal = UnsafeMutablePointer<Void>.alloc(1)
// Call the CoreFoundation function that copies the desired information as
// a CFBoolean to newly allocated memory that prt will point to on return.
if CFURLCopyResourcePropertyForKey(fUrl, kCFURLIsAliasFileKey, ptrPropVal, nil) {
// Extract the Bool value from the memory allocated.
isAlias = UnsafePointer<CFBoolean>(ptrPropVal).memory as Bool
// Since the CF*() call contains the word "Copy", WE are responsible
// for destroying (freeing) the memory.
ptrPropVal.destroy()
}
// Deallocate the pointer
ptrPropVal.dealloc(1)
return isAlias
}