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FlutterThreadSynchronizer.h
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1 // Copyright 2013 The Flutter Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #ifndef FLUTTER_SHELL_PLATFORM_DARWIN_MACOS_FRAMEWORK_SOURCE_FLUTTERTHREADSYNCHRONIZER_H_
6 #define FLUTTER_SHELL_PLATFORM_DARWIN_MACOS_FRAMEWORK_SOURCE_FLUTTERTHREADSYNCHRONIZER_H_
7
8 #import <Cocoa/Cocoa.h>
9
10 #import "flutter/shell/platform/darwin/macos/framework/Headers/FlutterViewController.h"
11
12 /**
13 * Takes care of synchronization between raster and platform thread.
14 *
15 * All methods of this class must be called from the platform thread,
16 * except for performCommitForView:size:notify:.
17 */
18 @interface FlutterThreadSynchronizer : NSObject
19
20 /**
21 * Creates a FlutterThreadSynchronizer that uses the OS main thread as the
22 * platform thread.
23 */
24 - (nullable instancetype)init;
25
26 /**
27 * Blocks until all views have a commit with their given sizes (or empty) is requested.
28 */
29 - (void)beginResizeForView:(FlutterViewIdentifier)viewIdentifier
30 size:(CGSize)size
31 notify:(nonnull dispatch_block_t)notify;
32
33 /**
34 * Called from raster thread. Schedules the given block on platform thread
35 * and blocks until it is performed.
36 *
37 * If platform thread is blocked in `beginResize:` for given size (or size is empty),
38 * unblocks platform thread.
39 *
40 * The notify block is guaranteed to be called within a core animation transaction.
41 */
42 - (void)performCommitForView:(FlutterViewIdentifier)viewIdentifier
43 size:(CGSize)size
44 notify:(nonnull dispatch_block_t)notify;
45
46 /**
47 * Schedules the given block to be performed on the platform thread.
48 * The block will be performed even if the platform thread is blocked waiting
49 * for a commit.
50 */
51 - (void)performOnPlatformThread:(nonnull dispatch_block_t)block;
52
53 /**
54 * Requests the synchronizer to track another view.
55 *
56 * A view must be registered before calling begineResizeForView: or
57 * performCommitForView:. It is typically done when the view controller is
58 * created.
59 */
60 - (void)registerView:(FlutterViewIdentifier)viewIdentifier;
61
62 /**
63 * Requests the synchronizer to no longer track a view.
64 *
65 * It is typically done when the view controller is destroyed.
66 */
67 - (void)deregisterView:(FlutterViewIdentifier)viewIdentifier;
68
69 /**
70 * Called when the engine shuts down.
71 *
72 * Prevents any further synchronization and no longer blocks any threads.
73 */
74 - (void)shutdown;
75
76 @end
77
78 @interface FlutterThreadSynchronizer (TestUtils)
79
80 /**
81 * Creates a FlutterThreadSynchronizer that uses the specified queue as the
82 * platform thread.
83 */
84 - (nullable instancetype)initWithMainQueue:(nonnull dispatch_queue_t)queue;
85
86 /**
87 * Blocks current thread until the mutex is available, then return whether the
88 * synchronizer is waiting for a correct commit during resizing.
89 *
90 * After calling an operation of the thread synchronizer, call this method,
91 * and when it returns, the thread synchronizer can be at one of the following 3
92 * states:
93 *
94 * 1. The operation has not started at all (with a return value FALSE.)
95 * 2. The operation has ended (with a return value FALSE.)
96 * 3. beginResizeForView: is in progress, waiting (with a return value TRUE.)
97 *
98 * By eliminating the 1st case (such as using the notify callback), we can use
99 * this return value to decide whether the synchronizer is in case 2 or case 3,
100 * that is whether the resizing is blocked by a mismatching commit.
101 */
102 - (BOOL)isWaitingWhenMutexIsAvailable;
103
104 /**
105 * Blocks current thread until there is frame available.
106 * Used in FlutterEngineTest.
107 */
108 - (void)blockUntilFrameAvailable;
109
110 @end
111
112 #endif // FLUTTER_SHELL_PLATFORM_DARWIN_MACOS_FRAMEWORK_SOURCE_FLUTTERTHREADSYNCHRONIZER_H_
FlutterViewController.h
FlutterViewIdentifier
int64_t FlutterViewIdentifier
Definition: FlutterViewController.h:21
FlutterThreadSynchronizer(TestUtils)
Definition: FlutterThreadSynchronizer.h:78
FlutterThreadSynchronizer
Definition: FlutterThreadSynchronizer.h:19
-[FlutterThreadSynchronizer shutdown]
void shutdown()
Definition: FlutterThreadSynchronizer.mm:192
-[FlutterThreadSynchronizer init]
nullable instancetype init()
Definition: FlutterThreadSynchronizer.mm:47