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Fix retain cycles in RTCUIApplicationStatusObserver.

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These retain cycles are theoretical since the singleton is supposed to
live for the lifetime of the application.

These measures were removed earlier when the object was turned into
a singleton in a previous CL, see
https://chromium-review.googlesource.com/c/external/webrtc/+/527442/3..4/webrtc/sdk/objc/Framework/Classes/Common/RTCUIApplicationStatusObserver.m

The weak self handling and unused dealloc method is mostly noise and
can make a casual reader think that the object will have a limited
life cycle, i.e. the code may initially look like something it is not,
which could possibly be less readable. On the other hand, for people
looking out for potential retain cycles, the code may be distracting
since it looks like it may be leaking.

BUG=b/65558647

Review-Url: https://codereview.webrtc.org/3013023002
Cr-Commit-Position: refs/heads/master@{#19811}
This commit is contained in:
andersc
2017-09-13 02:18:36 -07:00
committed by Commit Bot
parent 47791cf0f8
commit 4090f380e5
1 changed files with 36 additions and 14 deletions
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50
webrtc/sdk/objc/Framework/Classes/Common/RTCUIApplicationStatusObserver.m
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@ -16,12 +16,25 @@
#include "webrtc/rtc_base/checks.h"
@interface RTCUIApplicationStatusObserver ()
@property(nonatomic, assign) BOOL initialized;
@property(nonatomic, assign) UIApplicationState state;
@end
@implementation RTCUIApplicationStatusObserver {
BOOL _initialized;
dispatch_block_t _initializeBlock;
UIApplicationState _state;
id<NSObject> _activeObserver;
id<NSObject> _backgroundObserver;
}
@synthesize initialized = _initialized;
@synthesize state = _state;
+ (instancetype)sharedInstance {
static id sharedInstance;
static dispatch_once_t onceToken;
@ -35,24 +48,27 @@
- (id)init {
if (self = [super init]) {
NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
[center addObserverForName:UIApplicationDidBecomeActiveNotification
object:nil
queue:[NSOperationQueue mainQueue]
usingBlock:^(NSNotification *note) {
_state = [UIApplication sharedApplication].applicationState;
}];
__weak RTCUIApplicationStatusObserver *weakSelf = self;
_activeObserver = [center addObserverForName:UIApplicationDidBecomeActiveNotification
object:nil
queue:[NSOperationQueue mainQueue]
usingBlock:^(NSNotification *note) {
weakSelf.state =
[UIApplication sharedApplication].applicationState;
}];
[center addObserverForName:UIApplicationDidEnterBackgroundNotification
object:nil
queue:[NSOperationQueue mainQueue]
usingBlock:^(NSNotification *note) {
_state = [UIApplication sharedApplication].applicationState;
}];
_backgroundObserver = [center addObserverForName:UIApplicationDidEnterBackgroundNotification
object:nil
queue:[NSOperationQueue mainQueue]
usingBlock:^(NSNotification *note) {
weakSelf.state =
[UIApplication sharedApplication].applicationState;
}];
_initialized = NO;
_initializeBlock = dispatch_block_create(DISPATCH_BLOCK_INHERIT_QOS_CLASS, ^{
_state = [UIApplication sharedApplication].applicationState;
_initialized = YES;
weakSelf.state = [UIApplication sharedApplication].applicationState;
weakSelf.initialized = YES;
});
dispatch_async(dispatch_get_main_queue(), _initializeBlock);
@ -61,6 +77,12 @@
return self;
}
- (void)dealloc {
NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
[center removeObserver:_activeObserver];
[center removeObserver:_backgroundObserver];
}
- (BOOL)isApplicationActive {
if (!_initialized) {
long ret = dispatch_block_wait(_initializeBlock,