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[英]How do I create an IMServicePlugin on OS X? No documentation on file structure
[英]How do I watch for file changes on OS X?
我希望收到有關寫入給定文件的通知 - 無需輪詢,無需從文件中讀取,也無需監視父目錄並查看文件修改時間戳。 我怎么做?
我找不到一個簡單的例子,所以我正在貢獻我想出的東西供將來參考:
@interface FileWatch ()
@property(assign) dispatch_source_t source;
@end
@implementation FileWatch
@synthesize source;
- (id) initWithPath: (NSString*) path targetQueue: (dispatch_queue_t) queue block: (dispatch_block_t) handler
{
self = [super init];
int descriptor = open([path fileSystemRepresentation], O_EVTONLY);
if (descriptor < 0) {
return nil;
}
[self setSource:dispatch_source_create(DISPATCH_SOURCE_TYPE_VNODE, descriptor, DISPATCH_VNODE_WRITE, queue)];
dispatch_source_set_event_handler(source, handler);
dispatch_source_set_cancel_handler(source, ^{
close(descriptor);
});
dispatch_resume(source);
return self;
}
- (void) dealloc
{
if (source) {
dispatch_source_cancel(source);
dispatch_release(source);
source = NULL;
}
}
@end
從我的經驗來看,在某些情況下,文件不僅會被寫入,而是被刪除然后重寫(一些plist文件的情況)。 然后你必須稍微調整代碼:在ordre中替換文件時再次調用方法以保持監視。
- (void) myMonitoringMethodWithPath: :(NSString*) path
__block typeof(self) blockSelf = self;
__block dispatch_source_t source = dispatch_source_create(DISPATCH_SOURCE_TYPE_VNODE,fildes, DISPATCH_VNODE_DELETE | DISPATCH_VNODE_WRITE | DISPATCH_VNODE_EXTEND | DISPATCH_VNODE_ATTRIB | DISPATCH_VNODE_LINK | DISPATCH_VNODE_RENAME | DISPATCH_VNODE_REVOKE,
queue);
dispatch_source_set_event_handler(source, ^
{
unsigned long flags = dispatch_source_get_data(source);
//Do some stuff
if(flags & DISPATCH_VNODE_DELETE)
{
[blockSelf myMonitoringMethodWithPath:path];
}
});
dispatch_source_set_cancel_handler(source, ^(void)
{
close(fildes);
});
dispatch_resume(source);
}
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