Files
santa/Source/common/SNTFileWatcher.m

102 lines
3.1 KiB
Objective-C

/// Copyright 2015 Google Inc. All rights reserved.
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
/// http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
#import "SNTFileWatcher.h"
@interface SNTFileWatcher ()
@property NSString *filePath;
@property dispatch_source_t monitoringSource;
@property(strong) void (^eventHandler)(void);
@property(strong) void (^internalEventHandler)(void);
@property(strong) void (^internalCancelHandler)(void);
@end
@implementation SNTFileWatcher
- (instancetype)init {
[self doesNotRecognizeSelector:_cmd];
return nil;
}
- (instancetype)initWithFilePath:(NSString *)filePath handler:(void (^)(void))handler {
self = [super init];
if (self) {
_filePath = filePath;
_eventHandler = handler;
if (!_filePath || !_eventHandler) return nil;
[self beginWatchingFile];
}
return self;
}
- (void)dealloc {
[self stopWatchingFile];
}
- (void)beginWatchingFile {
__weak __typeof(self) weakSelf = self;
int mask = (DISPATCH_VNODE_DELETE | DISPATCH_VNODE_WRITE |
DISPATCH_VNODE_EXTEND | DISPATCH_VNODE_RENAME);
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0);
self.internalEventHandler = ^{
unsigned long l = dispatch_source_get_data(weakSelf.monitoringSource);
if (l & DISPATCH_VNODE_DELETE || l & DISPATCH_VNODE_RENAME) {
if (weakSelf.monitoringSource) dispatch_source_cancel(weakSelf.monitoringSource);
} else {
weakSelf.eventHandler();
}
};
self.internalCancelHandler = ^{
int fd;
if (weakSelf.monitoringSource) {
fd = (int)dispatch_source_get_handle(weakSelf.monitoringSource);
close(fd);
}
const char *filePathCString = [weakSelf.filePath fileSystemRepresentation];
while ((fd = open(filePathCString, O_EVTONLY)) < 0) {
usleep(1000);
}
weakSelf.monitoringSource =
dispatch_source_create(DISPATCH_SOURCE_TYPE_VNODE, fd, mask, queue);
dispatch_source_set_event_handler(weakSelf.monitoringSource, weakSelf.internalEventHandler);
dispatch_source_set_cancel_handler(weakSelf.monitoringSource, weakSelf.internalCancelHandler);
dispatch_resume(weakSelf.monitoringSource);
weakSelf.eventHandler();
};
dispatch_async(queue, self.internalCancelHandler);
}
- (void)stopWatchingFile {
if (!self.monitoringSource) return;
int fd = (int)dispatch_source_get_handle(self.monitoringSource);
dispatch_source_set_event_handler_f(self.monitoringSource, NULL);
dispatch_source_set_cancel_handler(self.monitoringSource, ^{ close(fd); });
dispatch_source_cancel(self.monitoringSource);
self.monitoringSource = nil;
}
@end