Implement screen capture for android

media/screen_capture/android/screen_capturer2_android.cc

+// Copyright (c) 2015 The Chromium 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 "media/screen_capture/android/screen_capturer2_android.h"
+
+#include "base/android/jni_android.h"
+#include "base/android/scoped_java_ref.h"
+#include "base/strings/string_number_conversions.h"
+#include "jni/ScreenCapture_jni.h"
+#include "media/base/video_capture_types.h"
+#include "media/screen_capture/android/screen_capture_factory_android.h"
+
+using base::android::AttachCurrentThread;
+
+namespace media {
+
+// static
+bool ScreenCapturer2Android::RegisterScreenCapturer2(JNIEnv* env) {
+  return media::RegisterNativesImpl(env);
+}
+
+ScreenCapturer2Android::ScreenCapturer2Android()
+    : state_(kIdle), got_first_frame_(false) {}
+
+ScreenCapturer2Android::~ScreenCapturer2Android() {
+  StopAndDeAllocate();
+}
+
+void ScreenCapturer2Android::OnFrameAvailable(JNIEnv* env,
+                                              jobject obj,
+                                              jbyteArray data,
+                                              jint length) {
+  base::AutoLock lock(lock_);
+  if (state_ != kCapturing || !client_.get())
+    return;
+
+  jbyte* buffer = env->GetByteArrayElements(data, NULL);
+  if (!buffer) {
+    LOG(ERROR) << "ScreenCapturer2Android::OnFrameAvailable: "
+                  "failed to GetByteArrayElements";
+    return;
+  }
+
+  base::TimeTicks current_time = base::TimeTicks::Now();
+  if (!got_first_frame_) {
+    // Set aside one frame allowance for fluctuation.
+    expected_next_frame_time_ = current_time - frame_interval_;
+    got_first_frame_ = true;
+  }
+
+  // Deliver the frame when it doesn't arrive too early.
+  if (expected_next_frame_time_ <= current_time) {
+    expected_next_frame_time_ += frame_interval_;
+
+    client_->OnIncomingCapturedData(reinterpret_cast<uint8*>(buffer),
+                                    length,
+                                    capture_format_,
+                                    0,
+                                    base::TimeTicks::Now());
+  }
+
+  env->ReleaseByteArrayElements(data, buffer, JNI_ABORT);
+}
+
+void ScreenCapturer2Android::OnActivityResult(JNIEnv* env,
+                                              jobject obj,
+                                              jint result) {
+  if (result == 0) {
+    state_ = kIdle;
+    return;
+  }
+
+  media::Java_ScreenCapture_startCapture(env, obj);
+
+  {
+    base::AutoLock lock(lock_);
+    state_ = kCapturing;
+  }
+}
+
+bool ScreenCapturer2Android::Init() {
+  j_capture_.Reset(media::ScreenCaptureFactoryAndroid
+      ::createScreenCapture2Android(reinterpret_cast<intptr_t>(this)));
+
+  if (j_capture_.obj() == NULL) {
+    LOG(ERROR) << "ScreenCapturer2Android::Init"
+                  " failed to createScreenCaptureAndroid,"
+                  " Maybe android version is too low";
+    return false;
+  }
+  return true;
+}
+
+void ScreenCapturer2Android::AllocateAndStart(
+    const VideoCaptureParams& params,
+    scoped_ptr<Client> client) {
+  DVLOG(1) << "ScreenCapturer2Android::AllocateAndStart";
+  {
+    base::AutoLock lock(lock_);
+    if (state_ != kIdle)
+      return;
+    client_ = client.Pass();
+    got_first_frame_ = false;
+  }
+/*
+  // Store current width and height.
+  capture_format_.frame_size.SetSize(
+      params.requested_format.frame_size.width(),
+      params.requested_format.frame_size.height());
+  capture_format_.frame_rate = params.requested_format.frame_rate;
+*/
+  capture_format_ = params.requested_format;
+  // This capturer always outputs ARGB, non-interlaced.
+  capture_format_.pixel_format = media::PIXEL_FORMAT_ARGB;
+
+  CHECK(capture_format_.frame_size.GetArea() > 0);
+  CHECK(!(capture_format_.frame_size.width() % 2));
+  CHECK(!(capture_format_.frame_size.height() % 2));
+
+  if (capture_format_.frame_rate > 0) {
+    frame_interval_ = base::TimeDelta::FromMicroseconds(
+        (base::Time::kMicrosecondsPerSecond + capture_format_.frame_rate - 1) /
+        capture_format_.frame_rate);
+  }
+
+  DVLOG(1) << "ScreenCapturer2Android::AllocateAndStart: queried frame_size="
+           << capture_format_.frame_size.ToString()
+           << ", frame_rate=" << capture_format_.frame_rate;
+
+  JNIEnv* env = AttachCurrentThread();
+  jboolean ret = media::Java_ScreenCapture_start(env, j_capture_.obj(),
+      capture_format_.frame_size.width(), capture_format_.frame_size.height());
+  if (!ret) {
+    {
+      base::AutoLock lock(lock_);
+      state_ = kError;
+    }
+    client_->OnError("Failed to start");
+    return;
+  }
+}
+
+void ScreenCapturer2Android::StopAndDeAllocate() {
+  DVLOG(1) << "ScreenCapturer2Android::StopAndDeAllocate";
+  {
+    base::AutoLock lock(lock_);
+    if (state_ != kCapturing && state_ != kError)
+      return;
+  }
+
+  JNIEnv* env = AttachCurrentThread();
+  Java_ScreenCapture_stopCapture(env, j_capture_.obj());
+
+  {
+    base::AutoLock lock(lock_);
+    state_ = kIdle;
+    client_.reset();
+  }
+}
+
+}  // namespace media