[engine] Sync Flutter 3.7 source code (#21)

flutter/shell/platform/common/BUILD.gn

@@ -8,6 +8,7 @@ config("desktop_library_implementation") {
 
 _public_headers = [
   "public/flutter_export.h",
+  "public/flutter_macros.h",
   "public/flutter_messenger.h",
   "public/flutter_plugin_registrar.h",
   "public/flutter_texture_registrar.h",

flutter/shell/platform/common/client_wrapper/core_implementations.cc

@@ -26,6 +26,11 @@ namespace flutter {
 // ========== binary_messenger_impl.h ==========
 
 namespace {
+
+using FlutterDesktopMessengerScopedLock =
+    std::unique_ptr<FlutterDesktopMessenger,
+                    decltype(&FlutterDesktopMessengerUnlock)>;
+
 // Passes |message| to |user_data|, which must be a BinaryMessageHandler, along
 // with a BinaryReply that will send a response on |message|'s response handle.
 //
@@ -36,17 +41,28 @@ void ForwardToHandler(FlutterDesktopMessengerRef messenger,
                       const FlutterDesktopMessage* message,
                       void* user_data) {
   auto* response_handle = message->response_handle;
-  BinaryReply reply_handler = [messenger, response_handle](
+  auto messenger_ptr = std::shared_ptr<FlutterDesktopMessenger>(
+      FlutterDesktopMessengerAddRef(messenger),
+      &FlutterDesktopMessengerRelease);
+  BinaryReply reply_handler = [messenger_ptr, response_handle](
                                   const uint8_t* reply,
                                   size_t reply_size) mutable {
+    // Note: This lambda can be called on any thread.
+    auto lock = FlutterDesktopMessengerScopedLock(
+        FlutterDesktopMessengerLock(messenger_ptr.get()),
+        &FlutterDesktopMessengerUnlock);
+    if (!FlutterDesktopMessengerIsAvailable(messenger_ptr.get())) {
+      // Drop reply if it comes in after the engine is destroyed.
+      return;
+    }
     if (!response_handle) {
       std::cerr << "Error: Response can be set only once. Ignoring "
                    "duplicate response."
                 << std::endl;
       return;
     }
-    FlutterDesktopMessengerSendResponse(messenger, response_handle, reply,
-                                        reply_size);
+    FlutterDesktopMessengerSendResponse(messenger_ptr.get(), response_handle,
+                                        reply, reply_size);
     // The engine frees the response handle once
     // FlutterDesktopSendMessageResponse is called.
     response_handle = nullptr;
@@ -195,9 +211,32 @@ bool TextureRegistrarImpl::MarkTextureFrameAvailable(int64_t texture_id) {
       texture_registrar_ref_, texture_id);
 }
 
+void TextureRegistrarImpl::UnregisterTexture(int64_t texture_id,
+                                             std::function<void()> callback) {
+  if (callback == nullptr) {
+    FlutterDesktopTextureRegistrarUnregisterExternalTexture(
+        texture_registrar_ref_, texture_id, nullptr, nullptr);
+    return;
+  }
+
+  struct Captures {
+    std::function<void()> callback;
+  };
+  auto captures = new Captures();
+  captures->callback = std::move(callback);
+  FlutterDesktopTextureRegistrarUnregisterExternalTexture(
+      texture_registrar_ref_, texture_id,
+      [](void* opaque) {
+        auto captures = reinterpret_cast<Captures*>(opaque);
+        captures->callback();
+        delete captures;
+      },
+      captures);
+}
+
 bool TextureRegistrarImpl::UnregisterTexture(int64_t texture_id) {
-  return FlutterDesktopTextureRegistrarUnregisterExternalTexture(
-      texture_registrar_ref_, texture_id);
+  UnregisterTexture(texture_id, nullptr);
+  return true;
 }
 
 }  // namespace flutter

flutter/shell/platform/common/client_wrapper/include/flutter/event_channel.h

@@ -47,10 +47,13 @@ class EventChannel {
   // Registers a stream handler on this channel.
   // If no handler has been registered, any incoming stream setup requests will
   // be handled silently by providing an empty stream.
+  //
+  // Note that the EventChannel does not own the handler and will not
+  // unregister it on destruction. The caller is responsible for unregistering
+  // the handler if it should no longer be called.
   void SetStreamHandler(std::unique_ptr<StreamHandler<T>> handler) {
     if (!handler) {
       messenger_->SetMessageHandler(name_, nullptr);
-      is_listening_ = false;
       return;
     }
 
@@ -61,69 +64,75 @@ class EventChannel {
     const MethodCodec<T>* codec = codec_;
     const std::string channel_name = name_;
     const BinaryMessenger* messenger = messenger_;
-    BinaryMessageHandler binary_handler = [shared_handler, codec, channel_name,
-                                           messenger,
-                                           this](const uint8_t* message,
-                                                 const size_t message_size,
-                                                 BinaryReply reply) {
-      constexpr char kOnListenMethod[] = "listen";
-      constexpr char kOnCancelMethod[] = "cancel";
-
-      std::unique_ptr<MethodCall<T>> method_call =
-          codec->DecodeMethodCall(message, message_size);
-      if (!method_call) {
-        std::cerr << "Unable to construct method call from message on channel: "
-                  << channel_name << std::endl;
-        reply(nullptr, 0);
-        return;
-      }
-
-      const std::string& method = method_call->method_name();
-      if (method.compare(kOnListenMethod) == 0) {
-        if (is_listening_) {
-          std::unique_ptr<StreamHandlerError<T>> error =
-              shared_handler->OnCancel(nullptr);
-          if (error) {
-            std::cerr << "Failed to cancel existing stream: "
-                      << (error->error_code) << ", " << (error->error_message)
-                      << ", " << (error->error_details);
+    BinaryMessageHandler binary_handler =
+        [shared_handler, codec, channel_name, messenger,
+         // Mutable state to track the handler's listening status.
+         is_listening = bool(false)](const uint8_t* message,
+                                     const size_t message_size,
+                                     BinaryReply reply) mutable {
+          constexpr char kOnListenMethod[] = "listen";
+          constexpr char kOnCancelMethod[] = "cancel";
+
+          std::unique_ptr<MethodCall<T>> method_call =
+              codec->DecodeMethodCall(message, message_size);
+          if (!method_call) {
+            std::cerr
+                << "Unable to construct method call from message on channel: "
+                << channel_name << std::endl;
+            reply(nullptr, 0);
+            return;
           }
-        }
-        is_listening_ = true;
-
-        std::unique_ptr<std::vector<uint8_t>> result;
-        auto sink = std::make_unique<EventSinkImplementation>(
-            messenger, channel_name, codec);
-        std::unique_ptr<StreamHandlerError<T>> error =
-            shared_handler->OnListen(method_call->arguments(), std::move(sink));
-        if (error) {
-          result = codec->EncodeErrorEnvelope(
-              error->error_code, error->error_message, error->error_details);
-        } else {
-          result = codec->EncodeSuccessEnvelope();
-        }
-        reply(result->data(), result->size());
-      } else if (method.compare(kOnCancelMethod) == 0) {
-        std::unique_ptr<std::vector<uint8_t>> result;
-        if (is_listening_) {
-          std::unique_ptr<StreamHandlerError<T>> error =
-              shared_handler->OnCancel(method_call->arguments());
-          if (error) {
-            result = codec->EncodeErrorEnvelope(
-                error->error_code, error->error_message, error->error_details);
+
+          const std::string& method = method_call->method_name();
+          if (method.compare(kOnListenMethod) == 0) {
+            if (is_listening) {
+              std::unique_ptr<StreamHandlerError<T>> error =
+                  shared_handler->OnCancel(nullptr);
+              if (error) {
+                std::cerr << "Failed to cancel existing stream: "
+                          << (error->error_code) << ", "
+                          << (error->error_message) << ", "
+                          << (error->error_details);
+              }
+            }
+            is_listening = true;
+
+            std::unique_ptr<std::vector<uint8_t>> result;
+            auto sink = std::make_unique<EventSinkImplementation>(
+                messenger, channel_name, codec);
+            std::unique_ptr<StreamHandlerError<T>> error =
+                shared_handler->OnListen(method_call->arguments(),
+                                         std::move(sink));
+            if (error) {
+              result = codec->EncodeErrorEnvelope(error->error_code,
+                                                  error->error_message,
+                                                  error->error_details);
+            } else {
+              result = codec->EncodeSuccessEnvelope();
+            }
+            reply(result->data(), result->size());
+          } else if (method.compare(kOnCancelMethod) == 0) {
+            std::unique_ptr<std::vector<uint8_t>> result;
+            if (is_listening) {
+              std::unique_ptr<StreamHandlerError<T>> error =
+                  shared_handler->OnCancel(method_call->arguments());
+              if (error) {
+                result = codec->EncodeErrorEnvelope(error->error_code,
+                                                    error->error_message,
+                                                    error->error_details);
+              } else {
+                result = codec->EncodeSuccessEnvelope();
+              }
+              is_listening = false;
+            } else {
+              result = codec->EncodeErrorEnvelope(
+                  "error", "No active stream to cancel", nullptr);
+            }
+            reply(result->data(), result->size());
           } else {
-            result = codec->EncodeSuccessEnvelope();
+            reply(nullptr, 0);
           }
-          is_listening_ = false;
-        } else {
-          result = codec->EncodeErrorEnvelope(
-              "error", "No active stream to cancel", nullptr);
-        }
-        reply(result->data(), result->size());
-      } else {
-        reply(nullptr, 0);
-      }
-    };
+        };
     messenger_->SetMessageHandler(name_, std::move(binary_handler));
   }
 
@@ -165,7 +174,6 @@ class EventChannel {
   BinaryMessenger* messenger_;
   const std::string name_;
   const MethodCodec<T>* codec_;
-  bool is_listening_ = false;
 };
 
 }  // namespace flutter

flutter/shell/platform/common/client_wrapper/include/flutter/texture_registrar.h

@@ -95,8 +95,13 @@ class TextureRegistrar {
   // the callback that was provided upon creating the texture.
   virtual bool MarkTextureFrameAvailable(int64_t texture_id) = 0;
 
-  // Unregisters an existing Texture object.
-  // Textures must not be unregistered while they're in use.
+  // Asynchronously unregisters an existing texture object.
+  // Upon completion, the optional |callback| gets invoked.
+  virtual void UnregisterTexture(int64_t texture_id,
+                                 std::function<void()> callback) = 0;
+
+  // Unregisters an existing texture object.
+  // DEPRECATED: Use UnregisterTexture(texture_id, optional_callback) instead.
   virtual bool UnregisterTexture(int64_t texture_id) = 0;
 };
 

flutter/shell/platform/common/client_wrapper/texture_registrar_impl.h

@@ -27,6 +27,10 @@ class TextureRegistrarImpl : public TextureRegistrar {
   // |flutter::TextureRegistrar|
   bool MarkTextureFrameAvailable(int64_t texture_id) override;
 
+  // |flutter::TextureRegistrar|
+  void UnregisterTexture(int64_t texture_id,
+                         std::function<void()> callback) override;
+
   // |flutter::TextureRegistrar|
   bool UnregisterTexture(int64_t texture_id) override;
 

flutter/shell/platform/common/incoming_message_dispatcher.cc

@@ -19,14 +19,15 @@ void IncomingMessageDispatcher::HandleMessage(
     const std::function<void(void)>& input_unblock_cb) {
   std::string channel(message.channel);
 
+  auto callback_iterator = callbacks_.find(channel);
   // Find the handler for the channel; if there isn't one, report the failure.
-  if (callbacks_.find(channel) == callbacks_.end()) {
+  if (callback_iterator == callbacks_.end()) {
     FlutterDesktopMessengerSendResponse(messenger_, message.response_handle,
                                         nullptr, 0);
     return;
   }
-  auto& callback_info = callbacks_[channel];
-  FlutterDesktopMessageCallback message_callback = callback_info.first;
+  auto& callback_info = callback_iterator->second;
+  const FlutterDesktopMessageCallback& message_callback = callback_info.first;
 
   // Process the call, handling input blocking if requested.
   bool block_input = input_blocking_channels_.count(channel) > 0;

flutter/shell/platform/common/public/flutter_export.h

@@ -6,8 +6,8 @@
 #define FLUTTER_SHELL_PLATFORM_COMMON_PUBLIC_FLUTTER_EXPORT_H_
 
 #ifdef FLUTTER_DESKTOP_LIBRARY
-// Add visibility/export annotations when building the library.
 
+// Add visibility/export annotations when building the library.
 #ifdef _WIN32
 #define FLUTTER_EXPORT __declspec(dllexport)
 #else

flutter/shell/platform/common/public/flutter_macros.h

@@ -0,0 +1,24 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef FLUTTER_SHELL_PLATFORM_COMMON_PUBLIC_FLUTTER_MACROS_H_
+#define FLUTTER_SHELL_PLATFORM_COMMON_PUBLIC_FLUTTER_MACROS_H_
+
+#ifdef FLUTTER_DESKTOP_LIBRARY
+
+// Do not add deprecation annotations when building the library.
+#define FLUTTER_DEPRECATED(message)
+
+#else  // FLUTTER_DESKTOP_LIBRARY
+
+// Add deprecation warning for users of the library.
+#ifdef _WIN32
+#define FLUTTER_DEPRECATED(message) __declspec(deprecated(message))
+#else
+#define FLUTTER_DEPRECATED(message) __attribute__((deprecated(message)))
+#endif
+
+#endif  // FLUTTER_DESKTOP_LIBRARY
+
+#endif  // FLUTTER_SHELL_PLATFORM_COMMON_PUBLIC_FLUTTER_MACROS_H_

flutter/shell/platform/common/public/flutter_messenger.h

@@ -5,6 +5,7 @@
 #ifndef FLUTTER_SHELL_PLATFORM_COMMON_PUBLIC_FLUTTER_MESSENGER_H_
 #define FLUTTER_SHELL_PLATFORM_COMMON_PUBLIC_FLUTTER_MESSENGER_H_
 
+#include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
 
@@ -87,6 +88,53 @@ FLUTTER_EXPORT void FlutterDesktopMessengerSetCallback(
     FlutterDesktopMessageCallback callback,
     void* user_data);
 
+// Increments the reference count for the |messenger|.
+//
+// Operation is thread-safe.
+//
+// See also: |FlutterDesktopMessengerRelease|
+FLUTTER_EXPORT FlutterDesktopMessengerRef
+FlutterDesktopMessengerAddRef(FlutterDesktopMessengerRef messenger);
+
+// Decrements the reference count for the |messenger|.
+//
+// Operation is thread-safe.
+//
+// See also: |FlutterDesktopMessengerAddRef|
+FLUTTER_EXPORT void FlutterDesktopMessengerRelease(
+    FlutterDesktopMessengerRef messenger);
+
+// Returns `true` if the |FlutterDesktopMessengerRef| still references a running
+// engine.
+//
+// This check should be made inside of a |FlutterDesktopMessengerLock| and
+// before any other calls are made to the FlutterDesktopMessengerRef when using
+// it from a thread other than the platform thread.
+FLUTTER_EXPORT bool FlutterDesktopMessengerIsAvailable(
+    FlutterDesktopMessengerRef messenger);
+
+// Locks the `FlutterDesktopMessengerRef` ensuring that
+// |FlutterDesktopMessengerIsAvailable| does not change while locked.
+//
+// All calls to the FlutterDesktopMessengerRef from threads other than the
+// platform thread should happen inside of a lock.
+//
+// Operation is thread-safe.
+//
+// Returns the |messenger| value.
+//
+// See also: |FlutterDesktopMessengerUnlock|
+FLUTTER_EXPORT FlutterDesktopMessengerRef
+FlutterDesktopMessengerLock(FlutterDesktopMessengerRef messenger);
+
+// Unlocks the `FlutterDesktopMessengerRef`.
+//
+// Operation is thread-safe.
+//
+// See also: |FlutterDesktopMessengerLock|
+FLUTTER_EXPORT void FlutterDesktopMessengerUnlock(
+    FlutterDesktopMessengerRef messenger);
+
 #if defined(__cplusplus)
 }  // extern "C"
 #endif