Signal-iOS/SignalServiceKit/src/Util/AppReadiness.m
2020-09-17 21:11:09 -03:00

139 lines
3.3 KiB
Objective-C
Executable File

//
// Copyright (c) 2020 Open Whisper Systems. All rights reserved.
//
#import "AppReadiness.h"
#import <SignalCoreKit/Threading.h>
#import <SignalServiceKit/SignalServiceKit-Swift.h>
NS_ASSUME_NONNULL_BEGIN
@interface AppReadiness ()
@property (nonatomic, readonly) ReadyFlag *readyFlag;
@end
#pragma mark -
@implementation AppReadiness
+ (instancetype)shared
{
static AppReadiness *sharedMyManager = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
sharedMyManager = [[self alloc] initDefault];
});
return sharedMyManager;
}
- (instancetype)initDefault
{
self = [super init];
if (!self) {
return self;
}
OWSSingletonAssert();
_readyFlag = [[ReadyFlag alloc] initWithName:@"AppReadiness" queueMode:QueueModeMainThreadOnly];
return self;
}
+ (BOOL)isAppReady
{
AppReadiness *instance = self.shared;
return [instance.readyFlag isSet];
}
+ (void)runNowOrWhenAppWillBecomeReady:(AppReadyBlock)block
{
DispatchMainThreadSafe(^{ [self.shared runNowOrWhenAppWillBecomeReady:block]; });
}
- (void)runNowOrWhenAppWillBecomeReady:(AppReadyBlock)block
{
OWSAssertIsOnMainThread();
OWSAssertDebug(block);
if (CurrentAppContext().isRunningTests) {
// We don't need to do any "on app ready" work in the tests.
return;
}
[self.readyFlag runNowOrWhenWillBecomeReady:block];
}
+ (void)runNowOrWhenAppDidBecomeReady:(AppReadyBlock)block
{
DispatchMainThreadSafe(^{ [self.shared runNowOrWhenAppDidBecomeReady:block]; });
}
- (void)runNowOrWhenAppDidBecomeReady:(AppReadyBlock)block
{
OWSAssertIsOnMainThread();
OWSAssertDebug(block);
if (CurrentAppContext().isRunningTests) {
// We don't need to do any "on app ready" work in the tests.
return;
}
[self.readyFlag runNowOrWhenDidBecomeReady:block];
}
+ (void)runNowOrWhenAppDidBecomeReadyPolite:(AppReadyBlock)block
{
DispatchMainThreadSafe(^{ [self.shared runNowOrWhenAppDidBecomeReadyPolite:block]; });
}
// We now have many (36+ in best case; many more in worst case)
// "app did become ready" blocks, many of which
// perform database writes. This can cause a "stampede" of writes
// as the app becomes ready. This can lead to 0x8badf00d crashes
// as the main thread can block behind these writes while trying
// to perform a checkpoint. The risk is highest on old devices
// with large databases. It can also simply cause the main thread
// to be less responsive.
//
// Most "App did become ready" blocks should be performed _soon_
// after launch but don't need to be performed sync. Therefore
// any blocks we
// perform them one-by-one with slight delays between them to
// reduce the risk of starving the main thread, especially if
// any given block is expensive.
- (void)runNowOrWhenAppDidBecomeReadyPolite:(AppReadyBlock)block
{
OWSAssertIsOnMainThread();
OWSAssertDebug(block);
if (CurrentAppContext().isRunningTests) {
// We don't need to do any "on app ready" work in the tests.
return;
}
[self.readyFlag runNowOrWhenDidBecomeReadyPolite:block];
}
+ (void)setAppIsReady
{
[self.shared setAppIsReady];
}
- (void)setAppIsReady
{
OWSAssertIsOnMainThread();
OWSAssertDebug(!self.readyFlag.isSet);
OWSLogInfo(@"");
[self.readyFlag setIsReady];
}
@end
NS_ASSUME_NONNULL_END