Files
santa/Source/common/SNTFileWatcher.m
2016-07-12 14:51:10 -04:00

102 lines
2.8 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"
#import "SNTStrengthify.h"
@interface SNTFileWatcher ()
@property NSString *filePath;
@property(strong) void (^handler)(unsigned long);
@property dispatch_source_t source;
@end
@implementation SNTFileWatcher
- (instancetype)init {
[self doesNotRecognizeSelector:_cmd];
return nil;
}
- (instancetype)initWithFilePath:(nonnull NSString *)filePath
handler:(nonnull void (^)(unsigned long))handler {
self = [super init];
if (self) {
_filePath = filePath;
_handler = handler;
[self startWatchingFile];
}
return self;
}
- (void)dealloc {
[self stopWatchingFile];
}
- (void)startWatchingFile {
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0);
int mask = (DISPATCH_VNODE_DELETE | DISPATCH_VNODE_RENAME |
DISPATCH_VNODE_WRITE | DISPATCH_VNODE_EXTEND | DISPATCH_VNODE_ATTRIB);
dispatch_async(queue, ^{
int fd = -1;
while ((fd = open([self.filePath fileSystemRepresentation], O_EVTONLY | O_CLOEXEC)) < 0) {
usleep(200000); // wait 200ms
}
self.source = dispatch_source_create(DISPATCH_SOURCE_TYPE_VNODE, fd, mask, queue);
WEAKIFY(self);
dispatch_source_set_event_handler(self.source, ^{
STRONGIFY(self);
unsigned long data = dispatch_source_get_data(self.source);
self.handler(data);
if (data & DISPATCH_VNODE_DELETE || data & DISPATCH_VNODE_RENAME) {
[self stopWatchingFile];
[self startWatchingFile];
}
sleep(2);
});
dispatch_source_set_registration_handler(self.source, ^{
STRONGIFY(self);
self.handler(0);
});
dispatch_source_set_cancel_handler(self.source, ^{
STRONGIFY(self);
int fd = (int)dispatch_source_get_handle(self.source);
if (fd > 0) close(fd);
});
dispatch_resume(self.source);
});
}
- (void)stopWatchingFile {
if (!self.source) return;
int fd = (int)dispatch_source_get_handle(self.source);
dispatch_source_set_event_handler_f(self.source, NULL);
dispatch_source_set_cancel_handler(self.source, ^{
close(fd);
});
dispatch_source_cancel(self.source);
self.source = nil;
}
@end