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flutter_desktop_messenger.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_WINDOWS_FLUTTER_DESKTOP_MESSENGER_H_
6 #define FLUTTER_SHELL_PLATFORM_WINDOWS_FLUTTER_DESKTOP_MESSENGER_H_
7
8 #include <atomic>
9 #include <mutex>
10
11 #include "flutter/fml/macros.h"
12 #include "flutter/shell/platform/common/public/flutter_messenger.h"
13
14 namespace flutter {
15
16 class FlutterWindowsEngine;
17
18 /// A messenger object used to invoke platform messages.
19 ///
20 /// On Windows, the message handler is essentially the |FlutterWindowsEngine|,
21 /// this allows a handle to the |FlutterWindowsEngine| that will become
22 /// invalidated if the |FlutterWindowsEngine| is destroyed.
23 class FlutterDesktopMessenger {
24 public:
25 FlutterDesktopMessenger() = default;
26
27 /// Convert to FlutterDesktopMessengerRef.
28 FlutterDesktopMessengerRef ToRef() {
29 return reinterpret_cast<FlutterDesktopMessengerRef>(this);
30 }
31
32 /// Convert from FlutterDesktopMessengerRef.
33 static FlutterDesktopMessenger* FromRef(FlutterDesktopMessengerRef ref) {
34 return reinterpret_cast<FlutterDesktopMessenger*>(ref);
35 }
36
37 /// Getter for the engine field.
38 flutter::FlutterWindowsEngine* GetEngine() const { return engine; }
39
40 /// Setter for the engine field.
41 /// Thread-safe.
42 void SetEngine(flutter::FlutterWindowsEngine* arg_engine) {
43 std::scoped_lock lock(mutex_);
44 engine = arg_engine;
45 }
46
47 /// Increments the reference count.
48 ///
49 /// Thread-safe.
50 FlutterDesktopMessenger* AddRef() {
51 ref_count_.fetch_add(1);
52 return this;
53 }
54
55 /// Decrements the reference count and deletes the object if the count has
56 /// gone to zero.
57 ///
58 /// Thread-safe.
59 void Release() {
60 int32_t old_count = ref_count_.fetch_sub(1);
61 if (old_count <= 1) {
62 delete this;
63 }
64 }
65
66 /// Returns the mutex associated with the |FlutterDesktopMessenger|.
67 ///
68 /// This mutex is used to synchronize reading or writing state inside the
69 /// |FlutterDesktopMessenger| (ie |engine|).
70 std::mutex& GetMutex() { return mutex_; }
71
72 private:
73 // The engine that owns this state object.
74 flutter::FlutterWindowsEngine* engine = nullptr;
75 std::mutex mutex_;
76 std::atomic<int32_t> ref_count_ = 0;
77
78 FML_DISALLOW_COPY_AND_ASSIGN(FlutterDesktopMessenger);
79 };
80
81 } // namespace flutter
82
83 #endif // FLUTTER_SHELL_PLATFORM_WINDOWS_FLUTTER_DESKTOP_MESSENGER_H_
flutter::FlutterWindowsEngine
Definition: flutter_windows_engine.h:90
flutter_messenger.h
flutter::FlutterDesktopMessenger::SetEngine
void SetEngine(flutter::FlutterWindowsEngine *arg_engine)
Definition: flutter_desktop_messenger.h:42
flutter::FlutterDesktopMessenger::ToRef
FlutterDesktopMessengerRef ToRef()
Convert to FlutterDesktopMessengerRef.
Definition: flutter_desktop_messenger.h:28
flutter::FlutterDesktopMessenger
Definition: flutter_desktop_messenger.h:23
flutter::FlutterDesktopMessenger::GetMutex
std::mutex & GetMutex()
Definition: flutter_desktop_messenger.h:70
flutter::FlutterDesktopMessenger::Release
void Release()
Definition: flutter_desktop_messenger.h:59
flutter
Definition: accessibility_bridge_windows.cc:11
flutter::FlutterDesktopMessenger::GetEngine
flutter::FlutterWindowsEngine * GetEngine() const
Getter for the engine field.
Definition: flutter_desktop_messenger.h:38
flutter::FlutterDesktopMessenger::AddRef
FlutterDesktopMessenger * AddRef()
Definition: flutter_desktop_messenger.h:50
flutter::FlutterDesktopMessenger::FlutterDesktopMessenger
FlutterDesktopMessenger()=default
FlutterDesktopMessengerRef
struct FlutterDesktopMessenger * FlutterDesktopMessengerRef
Definition: flutter_messenger.h:19
flutter::FlutterDesktopMessenger::FromRef
static FlutterDesktopMessenger * FromRef(FlutterDesktopMessengerRef ref)
Convert from FlutterDesktopMessengerRef.
Definition: flutter_desktop_messenger.h:33