[camera] Source code refactoring (#31)

Changes:
* Source code refactoring
* Add temporary code for camera image stream APIs

packages/camera/README.md

@@ -34,7 +34,7 @@ Import `camera` in your Dart code:
 import 'package:camera/camera.dart';
 ```
 
-## Troubleshoting
+## Troubleshooting
 
 If you get the following error:
 ```Shell
@@ -43,5 +43,6 @@ Wrong JPEG library version: library is 62, caller expects 80
 
 , try the following:
 ```Shell
-sudo mv /usr/lib/x86_64-linux-gnu/gstreamer-1.0/libgstjpeg.so /usr/lib/x86_64-linux-gnu/gstreamer-1.0/libgstjpeg.so.org
+sudo mv /usr/lib/x86_64-linux-gnu/gstreamer-1.0/libgstjpeg.so \
+        /usr/lib/x86_64-linux-gnu/gstreamer-1.0/libgstjpeg.so.org
 ```

packages/camera/elinux/CMakeLists.txt

@@ -12,12 +12,13 @@ pkg_check_modules(GSTREAMER REQUIRED gstreamer-1.0)
 
 add_library(${PLUGIN_NAME} SHARED
   "camera_elinux_plugin.cc"
+  "channels/event_channel_image_stream.cc"
+  "channels/method_channel_camera.cc"
+  "channels/method_channel_device.cc"
   "gst_camera.cc"
   "types/exposure_mode.cc"
   "types/focus_mode.cc"
   "types/orientation.cc"
-  "method_channel/method_channel_camera.cc"
-  "method_channel/method_channel_device.cc"
 )
 apply_standard_settings(${PLUGIN_NAME})
 set_target_properties(${PLUGIN_NAME} PROPERTIES

packages/camera/elinux/camera_elinux_plugin.cc

@@ -11,11 +11,12 @@
 #include <memory>
 
 #include "camera_stream_handler_impl.h"
+#include "channels/event_channel_image_stream.h"
+#include "channels/method_channel_camera.h"
+#include "channels/method_channel_device.h"
 #include "events/camera_initialized_event.h"
 #include "gst_camera.h"
 #include "messages/messages.h"
-#include "method_channel/method_channel_camera.h"
-#include "method_channel/method_channel_device.h"
 
 namespace {
 constexpr char kCameraChannelName[] = "plugins.flutter.io/camera";
@@ -82,6 +83,12 @@ class CameraPlugin : public flutter::Plugin {
   void HandleInitializeCall(
       const flutter::EncodableValue* message,
       std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>> result);
+  void HandleStartImageStreamCall(
+      const flutter::EncodableValue* message,
+      std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>> result);
+  void HandleStopImageStreamCall(
+      const flutter::EncodableValue* message,
+      std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>> result);
   void HandleGetMaxZoomLevelCall(
       const flutter::EncodableValue* message,
       std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>> result);
@@ -105,6 +112,9 @@ class CameraPlugin : public flutter::Plugin {
   std::unique_ptr<flutter::TextureVariant> texture_;
   std::unique_ptr<GstCamera> camera_ = nullptr;
   int64_t texture_id_;
+
+  std::unique_ptr<EventChannelImageStream> event_channel_image_stream_ =
+      nullptr;
   std::unique_ptr<MethodChannelCamera> method_channel_camera_;
   std::unique_ptr<MethodChannelDevice> method_channel_device_;
 };
@@ -168,9 +178,9 @@ void CameraPlugin::HandleMethodCall(
   } else if (!method_name.compare(kCameraChannelApiSetFocusPoint)) {
     result->NotImplemented();
   } else if (!method_name.compare(kCameraChannelApiStartImageStream)) {
-    result->NotImplemented();
+    HandleStartImageStreamCall(method_call.arguments(), std::move(result));
   } else if (!method_name.compare(kCameraChannelApiStopImageStream)) {
-    result->NotImplemented();
+    HandleStopImageStreamCall(method_call.arguments(), std::move(result));
   } else if (!method_name.compare(kCameraChannelApiGetMaxZoomLevel)) {
     HandleGetMaxZoomLevelCall(method_call.arguments(), std::move(result));
   } else if (!method_name.compare(kCameraChannelApiGetMinZoomLevel)) {
@@ -208,28 +218,30 @@ void CameraPlugin::HandleAvailableCamerasCall(
 void CameraPlugin::HandleCreateCall(
     const flutter::EncodableValue* message,
     std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>> result) {
-  // auto meta = CreateMessage::FromMap(message);
-
   buffer_ = std::make_unique<FlutterDesktopPixelBuffer>();
   texture_ =
       std::make_unique<flutter::TextureVariant>(flutter::PixelBufferTexture(
-          [host = this](size_t width,
+          [this](size_t width,
                  size_t height) -> const FlutterDesktopPixelBuffer* {
-            host->buffer_->width = host->camera_->GetPreviewWidth();
-            host->buffer_->height = host->camera_->GetPreviewHeight();
-            host->buffer_->buffer = host->camera_->GetPreviewFrameBuffer();
-            return host->buffer_.get();
+            buffer_->width = camera_->GetPreviewWidth();
+            buffer_->height = camera_->GetPreviewHeight();
+            buffer_->buffer = camera_->GetPreviewFrameBuffer();
+
+            // TODO: We need to handle this code (event_channel_image_stream_)
+            // in the proper place, but the Camera plugin doesn't have a main
+            // loop.
+            if (event_channel_image_stream_) {
+              event_channel_image_stream_->Send(buffer_->width, buffer_->height,
+                                                buffer_->buffer);
+            }
+
+            return buffer_.get();
           }));
   auto texture_id = texture_registrar_->RegisterTexture(texture_.get());
-  auto stream_handler = std::make_unique<CameraStreamHandlerImpl>(
-      // OnNotifyInitialized
-      []() {},
-      // OnNotifyFrameDecoded
-      [texture_id, host = this]() {
-        host->texture_registrar_->MarkTextureFrameAvailable(texture_id);
-      },
-      // OnNotifyCompleted
-      []() {});
+  auto stream_handler =
+      std::make_unique<CameraStreamHandlerImpl>([texture_id, this]() {
+        texture_registrar_->MarkTextureFrameAvailable(texture_id);
+      });
 
   camera_ = std::make_unique<GstCamera>(std::move(stream_handler));
   texture_id_ = texture_id;
@@ -273,6 +285,31 @@ void CameraPlugin::HandleInitializeCall(
   result->Success();
 }
 
+void CameraPlugin::HandleStartImageStreamCall(
+    const flutter::EncodableValue* message,
+    std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>> result) {
+// TODO: Support StartImageStream API.
+#if 0
+  event_channel_image_stream_ =
+      std::make_unique<EventChannelImageStream>(plugin_registrar_);
+  result->Success();
+#else
+  result->NotImplemented();
+#endif
+}
+
+void CameraPlugin::HandleStopImageStreamCall(
+    const flutter::EncodableValue* message,
+    std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>> result) {
+// TODO: Support StopImageStream API.
+#if 0
+  event_channel_image_stream_ = nullptr;
+  result->Success();
+#else
+  result->NotImplemented();
+#endif
+}
+
 void CameraPlugin::HandleGetMaxZoomLevelCall(
     const flutter::EncodableValue* message,
     std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>> result) {

packages/camera/elinux/camera_stream_handler.h

@@ -14,19 +14,11 @@ class CameraStreamHandler {
   CameraStreamHandler(CameraStreamHandler const&) = delete;
   CameraStreamHandler& operator=(CameraStreamHandler const&) = delete;
 
-  // Notifies the completion of initializing the video player.
-  void OnNotifyInitialized() { OnNotifyInitializedInternal(); }
-
   // Notifies the completion of decoding a video frame.
   void OnNotifyFrameDecoded() { OnNotifyFrameDecodedInternal(); }
 
-  // Notifies the completion of playing a video.
-  void OnNotifyCompleted() { OnNotifyCompletedInternal(); }
-
  protected:
-  virtual void OnNotifyInitializedInternal() = 0;
   virtual void OnNotifyFrameDecodedInternal() = 0;
-  virtual void OnNotifyCompletedInternal() = 0;
 };
 
 #endif  // PACKAGES_CAMERA_CAMERA_ELINUX_CAMERA_STREAM_HANDLER_H_

packages/camera/elinux/camera_stream_handler_impl.h

@@ -11,16 +11,10 @@
 
 class CameraStreamHandlerImpl : public CameraStreamHandler {
  public:
-  using OnNotifyInitialized = std::function<void()>;
   using OnNotifyFrameDecoded = std::function<void()>;
-  using OnNotifyCompleted = std::function<void()>;
 
-  CameraStreamHandlerImpl(OnNotifyInitialized on_notify_initialized,
-                          OnNotifyFrameDecoded on_notify_frame_decoded,
-                          OnNotifyCompleted on_notify_completed)
-      : on_notify_initialized_(on_notify_initialized),
-        on_notify_frame_decoded_(on_notify_frame_decoded),
-        on_notify_completed_(on_notify_completed) {}
+  CameraStreamHandlerImpl(OnNotifyFrameDecoded on_notify_frame_decoded)
+      : on_notify_frame_decoded_(on_notify_frame_decoded) {}
   virtual ~CameraStreamHandlerImpl() = default;
 
   // Prevent copying.
@@ -28,13 +22,6 @@ class CameraStreamHandlerImpl : public CameraStreamHandler {
   CameraStreamHandlerImpl& operator=(CameraStreamHandlerImpl const&) = delete;
 
  protected:
-  // |CameraStreamHandler|
-  void OnNotifyInitializedInternal() {
-    if (on_notify_initialized_) {
-      on_notify_initialized_();
-    }
-  }
-
   // |CameraStreamHandler|
   void OnNotifyFrameDecodedInternal() {
     if (on_notify_frame_decoded_) {
@@ -42,16 +29,7 @@ class CameraStreamHandlerImpl : public CameraStreamHandler {
     }
   }
 
-  // |CameraStreamHandler|
-  void OnNotifyCompletedInternal() {
-    if (on_notify_completed_) {
-      on_notify_completed_();
-    }
-  }
-
-  OnNotifyInitialized on_notify_initialized_;
   OnNotifyFrameDecoded on_notify_frame_decoded_;
-  OnNotifyCompleted on_notify_completed_;
 };
 
 #endif  // PACKAGES_CAMERA_CAMERA_ELINUX_CAMERA_STREAM_HANDLER_IMPL_H_

packages/camera/elinux/channels/event_channel_image_stream.cc

@@ -0,0 +1,72 @@
+// Copyright 2021 Sony Group Corporation. All rights reserved.
+// 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.
+
+#include "channels/event_channel_image_stream.h"
+
+#include <flutter/event_stream_handler_functions.h>
+#include <flutter/standard_method_codec.h>
+
+#include <vector>
+
+namespace {
+constexpr char kChannelName[] = "plugins.flutter.io/camera/imageStream";
+
+// See: [getFormat()] in
+// https://developer.android.com/reference/android/media/Image
+constexpr int32_t kImageFormatRGBA8888 = 4;
+};  // namespace
+
+EventChannelImageStream::EventChannelImageStream(
+    flutter::PluginRegistrar* registrar) {
+  auto event_channel =
+      std::make_unique<flutter::EventChannel<flutter::EncodableValue>>(
+          registrar->messenger(), kChannelName,
+          &flutter::StandardMethodCodec::GetInstance());
+
+  auto event_channel_handler = std::make_unique<
+      flutter::StreamHandlerFunctions<flutter::EncodableValue>>(
+      [this](
+          const flutter::EncodableValue* arguments,
+          std::unique_ptr<flutter::EventSink<flutter::EncodableValue>>&& events)
+          -> std::unique_ptr<
+              flutter::StreamHandlerError<flutter::EncodableValue>> {
+        event_sink_ = std::move(events);
+        return nullptr;
+      },
+      [this](const flutter::EncodableValue* arguments)
+          -> std::unique_ptr<
+              flutter::StreamHandlerError<flutter::EncodableValue>> {
+        event_sink_ = nullptr;
+        return nullptr;
+      });
+  event_channel->SetStreamHandler(std::move(event_channel_handler));
+}
+
+// See: [setImageStreamImageAvailableListener] in
+// flutter/plugins/packages/camera/camera/android/src/main/java/io/flutter/plugins/camera/Camera.java
+void EventChannelImageStream::Send(const int32_t& width, const int32_t& height,
+                                   const uint8_t* pixels) {
+  const uint32_t len = width * 4 * height;
+  std::vector<uint8_t> bytes(pixels, pixels + len);
+
+  flutter::EncodableList planes;
+  flutter::EncodableMap plane = {
+      {flutter::EncodableValue("bytesPerRow"), flutter::EncodableValue(width)},
+      {flutter::EncodableValue("bytesPerPixel"), flutter::EncodableValue(4)},
+      {flutter::EncodableValue("bytes"), flutter::EncodableValue(bytes)},
+  };
+  flutter::EncodableValue plane_value(plane);
+  planes.push_back(plane_value);
+
+  flutter::EncodableMap encodables = {
+      {flutter::EncodableValue("width"), flutter::EncodableValue(width)},
+      {flutter::EncodableValue("height"), flutter::EncodableValue(height)},
+      {flutter::EncodableValue("format"),
+       flutter::EncodableValue(kImageFormatRGBA8888)},
+      {flutter::EncodableValue("planes"), flutter::EncodableValue(planes)}};
+  flutter::EncodableValue event(encodables);
+
+  event_sink_->Success(event);
+}

packages/camera/elinux/channels/event_channel_image_stream.h

@@ -0,0 +1,27 @@
+// Copyright 2021 Sony Group Corporation. All rights reserved.
+// 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 PACKAGES_CAMERA_CAMERA_ELINUX_CAMERA_CHANNELS_EVENT_CHANNEL_IMAGE_STREAM_H_
+#define PACKAGES_CAMERA_CAMERA_ELINUX_CAMERA_CHANNELS_EVENT_CHANNEL_IMAGE_STREAM_H_
+
+#include <flutter/encodable_value.h>
+#include <flutter/event_channel.h>
+#include <flutter/plugin_registrar.h>
+
+#include <string>
+
+class EventChannelImageStream {
+ public:
+  EventChannelImageStream(flutter::PluginRegistrar* registrar);
+  ~EventChannelImageStream() = default;
+
+  void Send(const int32_t& width, const int32_t& height, const uint8_t* pixels);
+
+ private:
+  std::unique_ptr<flutter::EventChannel<flutter::EncodableValue>> channel_;
+  std::unique_ptr<flutter::EventSink<flutter::EncodableValue>> event_sink_;
+};
+
+#endif  // PACKAGES_CAMERA_CAMERA_ELINUX_CAMERA_CHANNELS_EVENT_CHANNEL_IMAGE_STREAM_H_

packages/camera/elinux/channels/method_channel_camera.cc

@@ -3,7 +3,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "method_channel/method_channel_camera.h"
+#include "channels/method_channel_camera.h"
 
 #include <flutter/standard_method_codec.h>
 

packages/camera/elinux/channels/method_channel_camera.h

@@ -3,8 +3,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef PACKAGES_CAMERA_CAMERA_ELINUX_CAMERA_METHOD_CHANNEL_METHOD_CHANNEL_CAMERA_H_
-#define PACKAGES_CAMERA_CAMERA_ELINUX_CAMERA_METHOD_CHANNEL_METHOD_CHANNEL_CAMERA_H_
+#ifndef PACKAGES_CAMERA_CAMERA_ELINUX_CAMERA_CHANNELS_METHOD_CHANNEL_CAMERA_H_
+#define PACKAGES_CAMERA_CAMERA_ELINUX_CAMERA_CHANNELS_METHOD_CHANNEL_CAMERA_H_
 
 #include <flutter/encodable_value.h>
 #include <flutter/method_channel.h>
@@ -14,12 +14,6 @@
 
 #include "events/camera_initialized_event.h"
 
-enum class CameraEventType {
-  kError,
-  kCameraClosing,
-  kInitialized,
-};
-
 class MethodChannelCamera {
  public:
   MethodChannelCamera(flutter::PluginRegistrar* registrar, int64_t camera_id);
@@ -34,4 +28,4 @@ class MethodChannelCamera {
   std::unique_ptr<flutter::MethodChannel<flutter::EncodableValue>> channel_;
 };
 
-#endif  // PACKAGES_CAMERA_CAMERA_ELINUX_CAMERA_METHOD_CHANNEL_METHOD_CHANNEL_CAMERA_H_
+#endif  // PACKAGES_CAMERA_CAMERA_ELINUX_CAMERA_CHANNELS_METHOD_CHANNEL_CAMERA_H_

packages/camera/elinux/channels/method_channel_device.cc

@@ -3,7 +3,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "method_channel/method_channel_device.h"
+#include "channels/method_channel_device.h"
 
 #include <flutter/standard_method_codec.h>
 

packages/camera/elinux/channels/method_channel_device.h

@@ -3,8 +3,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef PACKAGES_CAMERA_CAMERA_ELINUX_CAMERA_METHOD_CHANNEL_METHOD_CHANNEL_DEVICE_H_
-#define PACKAGES_CAMERA_CAMERA_ELINUX_CAMERA_METHOD_CHANNEL_METHOD_CHANNEL_DEVICE_H_
+#ifndef PACKAGES_CAMERA_CAMERA_ELINUX_CAMERA_CHANNELS_METHOD_CHANNEL_DEVICE_H_
+#define PACKAGES_CAMERA_CAMERA_ELINUX_CAMERA_CHANNELS_METHOD_CHANNEL_DEVICE_H_
 
 #include <flutter/encodable_value.h>
 #include <flutter/method_channel.h>
@@ -28,4 +28,4 @@ class MethodChannelDevice {
   std::unique_ptr<flutter::MethodChannel<flutter::EncodableValue>> channel_;
 };
 
-#endif  // PACKAGES_CAMERA_CAMERA_ELINUX_CAMERA_METHOD_CHANNEL_METHOD_CHANNEL_DEVICE_H_
+#endif  // PACKAGES_CAMERA_CAMERA_ELINUX_CAMERA_CHANNELS_METHOD_CHANNEL_DEVICE_H_