feat: Add streaming handlers for live TV proxying and VOD HLS transcoding using FFmpeg.

windows/flutter/ephemeral/flutter_messenger.h

@@ -0,0 +1,144 @@
+// 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_MESSENGER_H_
+#define FLUTTER_SHELL_PLATFORM_COMMON_PUBLIC_FLUTTER_MESSENGER_H_
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "flutter_export.h"
+
+#if defined(__cplusplus)
+extern "C" {
+#endif  // defined(__cplusplus)
+
+// Opaque reference to a Flutter engine messenger.
+typedef struct FlutterDesktopMessenger* FlutterDesktopMessengerRef;
+
+// Opaque handle for tracking responses to messages.
+typedef struct _FlutterPlatformMessageResponseHandle
+    FlutterDesktopMessageResponseHandle;
+
+// The callback expected as a response of a binary message.
+typedef void (*FlutterDesktopBinaryReply)(const uint8_t* data,
+                                          size_t data_size,
+                                          void* user_data);
+
+// A message received from Flutter.
+typedef struct {
+  // Size of this struct as created by Flutter.
+  size_t struct_size;
+  // The name of the channel used for this message.
+  const char* channel;
+  // The raw message data.
+  const uint8_t* message;
+  // The length of |message|.
+  size_t message_size;
+  // The response handle. If non-null, the receiver of this message must call
+  // FlutterDesktopSendMessageResponse exactly once with this handle.
+  const FlutterDesktopMessageResponseHandle* response_handle;
+} FlutterDesktopMessage;
+
+// Function pointer type for message handler callback registration.
+//
+// The user data will be whatever was passed to FlutterDesktopSetMessageHandler
+// for the channel the message is received on.
+typedef void (*FlutterDesktopMessageCallback)(
+    FlutterDesktopMessengerRef /* messenger */,
+    const FlutterDesktopMessage* /* message*/,
+    void* /* user data */);
+
+// Sends a binary message to the Flutter side on the specified channel.
+FLUTTER_EXPORT bool FlutterDesktopMessengerSend(
+    FlutterDesktopMessengerRef messenger,
+    const char* channel,
+    const uint8_t* message,
+    const size_t message_size);
+
+// Sends a binary message to the Flutter side on the specified channel.
+// The |reply| callback will be executed when a response is received.
+FLUTTER_EXPORT bool FlutterDesktopMessengerSendWithReply(
+    FlutterDesktopMessengerRef messenger,
+    const char* channel,
+    const uint8_t* message,
+    const size_t message_size,
+    const FlutterDesktopBinaryReply reply,
+    void* user_data);
+
+// Sends a reply to a FlutterDesktopMessage for the given response handle.
+//
+// Once this has been called, |handle| is invalid and must not be used again.
+FLUTTER_EXPORT void FlutterDesktopMessengerSendResponse(
+    FlutterDesktopMessengerRef messenger,
+    const FlutterDesktopMessageResponseHandle* handle,
+    const uint8_t* data,
+    size_t data_length);
+
+// Registers a callback function for incoming binary messages from the Flutter
+// side on the specified channel.
+//
+// Replaces any existing callback. Provide a null handler to unregister the
+// existing callback.
+//
+// If |user_data| is provided, it will be passed in |callback| calls.
+FLUTTER_EXPORT void FlutterDesktopMessengerSetCallback(
+    FlutterDesktopMessengerRef messenger,
+    const char* channel,
+    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
+
+#endif  // FLUTTER_SHELL_PLATFORM_COMMON_PUBLIC_FLUTTER_MESSENGER_H_