105 lines
2.3 KiB
Objective-C
105 lines
2.3 KiB
Objective-C
//
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// Copyright 2019 Signal Messenger, LLC
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// SPDX-License-Identifier: AGPL-3.0-only
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//
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#import "SDSCrossProcess.h"
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#import "DarwinNotificationCenter.h"
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#import <SignalServiceKit/OWSAsserts.h>
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#import <SignalServiceKit/SignalServiceKit-Swift.h>
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NS_ASSUME_NONNULL_BEGIN
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// NOTE: CFNotificationCenterGetDarwinNotifyCenter() might offer a better / equivalent solution,
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// but it wasn't working for me and so I moved on.
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static pid_t localPid(void)
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{
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static dispatch_once_t onceToken;
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static pid_t pid;
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dispatch_once(&onceToken, ^{ pid = getpid(); });
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return pid;
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}
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#pragma mark -
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@interface SDSCrossProcess ()
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@property (nonatomic) int notifyToken;
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@end
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#pragma mark -
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@implementation SDSCrossProcess
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- (id)init
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{
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if (self = [super init]) {
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self.notifyToken = DarwinNotificationInvalidObserver;
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[self start];
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}
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return self;
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}
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- (void)dealloc
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{
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[self stop];
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}
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- (void)start
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{
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[self stop];
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__weak SDSCrossProcess *weakSelf = self;
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self.notifyToken =
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[DarwinNotificationCenter addObserverForName:DarwinNotificationName.sdsCrossProcess
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queue:dispatch_get_main_queue()
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usingBlock:^(int token) { [weakSelf handleNotification:token]; }];
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}
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- (void)handleNotification:(int)token
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{
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OWSAssertIsOnMainThread();
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uint64_t fromPid = [DarwinNotificationCenter getStateForObserver:token];
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BOOL isLocal = fromPid == (uint64_t)localPid();
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if (isLocal) {
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return;
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}
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if (self.callback) {
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self.callback();
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}
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}
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- (void)stop
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{
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if ([DarwinNotificationCenter isValidObserver:self.notifyToken]) {
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[DarwinNotificationCenter removeObserver:self.notifyToken];
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}
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self.notifyToken = DarwinNotificationInvalidObserver;
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}
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- (void)notifyChangedAsync
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{
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dispatch_async(dispatch_get_main_queue(), ^{ [self notifyChanged]; });
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}
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- (void)notifyChanged
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{
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OWSAssertIsOnMainThread();
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if (![DarwinNotificationCenter isValidObserver:self.notifyToken]) {
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[self start];
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}
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[DarwinNotificationCenter setState:(uint64_t)localPid() forObserver:self.notifyToken];
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[DarwinNotificationCenter postNotificationName:DarwinNotificationName.sdsCrossProcess];
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}
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@end
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NS_ASSUME_NONNULL_END
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