ScreenCapture for Android phase1, part I

media/capture/content/android/java/src/org/chromium/media/ScreenCapture.java

Index: media/capture/content/android/java/src/org/chromium/media/ScreenCapture.java
diff --git a/media/capture/content/android/java/src/org/chromium/media/ScreenCapture.java b/media/capture/content/android/java/src/org/chromium/media/ScreenCapture.java
new file mode 100644
index 0000000000000000000000000000000000000000..a84b755e4b94007b631ac508527f246b294f9295
--- /dev/null
+++ b/media/capture/content/android/java/src/org/chromium/media/ScreenCapture.java
@@ -0,0 +1,352 @@
+// Copyright 2016 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.
+
+package org.chromium.media;
+
+import android.annotation.TargetApi;
+import android.app.Activity;
+import android.app.Fragment;
+import android.app.FragmentManager;
+import android.app.FragmentTransaction;
+import android.content.Context;
+import android.content.Intent;
+import android.graphics.ImageFormat;
+import android.graphics.PixelFormat;
+import android.hardware.display.DisplayManager;
+import android.hardware.display.VirtualDisplay;
+import android.media.Image;
+import android.media.ImageReader;
+import android.media.projection.MediaProjection;
+import android.media.projection.MediaProjectionManager;
+import android.os.Build;
+import android.os.Handler;
+import android.os.HandlerThread;
+import android.util.DisplayMetrics;
+import android.view.Display;
+import android.view.Surface;
+
+import org.chromium.base.ApplicationStatus;
+import org.chromium.base.Log;
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.base.annotations.JNINamespace;
+
+import java.nio.ByteBuffer;
+
+/**
+ * This class implements Screen Capture using projection API, introduced in Android
+ * API 21 (L Release). Capture takes place in the current Looper, while pixel
+ * download takes place in another thread used by ImageReader.
+ **/
+@JNINamespace("media")
+@TargetApi(Build.VERSION_CODES.LOLLIPOP)
+public class ScreenCapture extends Fragment {
+    // Internal class implementing the ImageReader listener. Gets pinged when a
+    // new frame is been captured and downloaded to memory-backed buffers.
+    // TODO(braveyao): This is very similar as the one in VideoCaptureCamera2. Try to see
+    // if we can extend from it, https://crbug.com/487935.
+    private class CrImageReaderListener implements ImageReader.OnImageAvailableListener {
+        @Override
+        public void onImageAvailable(ImageReader reader) {
+            synchronized (mCaptureStateLock) {
+                if (mCaptureState != CaptureState.STARTED) {
+                    Log.e(TAG, "Get captured frame in unexpected state.");
+                    return;
+                }
+            }
+
+            try (Image image = reader.acquireLatestImage()) {
+                if (image == null) return;
+                if (reader.getWidth() != image.getWidth()
+                        || reader.getHeight() != image.getHeight()) {
+                    Log.e(TAG, "ImageReader size (" + reader.getWidth() + "x" + reader.getHeight()
+                                    + ") did not match Image size (" + image.getWidth() + "x"
+                                    + image.getHeight() + ")");
+                    throw new IllegalStateException();
+                }
+
+                switch (image.getFormat()) {
+                    case PixelFormat.RGBA_8888:
+                        if (image.getPlanes().length != 1) {
+                            Log.e(TAG, "Unexpected image planes for RGBA_8888 format: "
+                                            + image.getPlanes().length);
+                            throw new IllegalStateException();
+                        }
+
+                        nativeOnRGBAFrameAvailable(mNativeScreenCaptureMachineAndroid,
+                                image.getPlanes()[0].getBuffer(),
+                                image.getPlanes()[0].getRowStride(), image.getCropRect().left,
+                                image.getCropRect().top, image.getCropRect().width(),
+                                image.getCropRect().height(), image.getTimestamp());
+                        break;
+                    case ImageFormat.YUV_420_888:
+                        if (image.getPlanes().length != 3) {
+                            Log.e(TAG, "Unexpected image planes for YUV_420_888 format: "
+                                            + image.getPlanes().length);
+                            throw new IllegalStateException();
+                        }
+
+                        // The pixel stride of Y plane is always 1. The U/V planes are guaranteed
+                        // to have the same row stride and pixel stride.
+                        nativeOnI420FrameAvailable(mNativeScreenCaptureMachineAndroid,
+                                image.getPlanes()[0].getBuffer(),
+                                image.getPlanes()[0].getRowStride(),
+                                image.getPlanes()[1].getBuffer(), image.getPlanes()[2].getBuffer(),
+                                image.getPlanes()[1].getRowStride(),
+                                image.getPlanes()[1].getPixelStride(), image.getCropRect().left,
+                                image.getCropRect().top, image.getCropRect().width(),
+                                image.getCropRect().height(), image.getTimestamp());
+                        break;
+                    default:
+                        Log.e(TAG, "Unexpected image format: " + image.getFormat());
+                        throw new IllegalStateException();
+                }
+            } catch (IllegalStateException ex) {
+                Log.e(TAG, "acquireLatestImage():" + ex);
+            } catch (UnsupportedOperationException ex) {
+                Log.i(TAG, "acquireLatestImage():" + ex);
+                // YUV_420_888 is the preference, but not all devices support it,
+                // fall-back to RGBA_8888 then.
+                mImageReader.close();
+                mVirtualDisplay.release();
+
+                mFormat = PixelFormat.RGBA_8888;
+                createImageReaderWithFormat(mFormat);
+                createVirtualDisplay();
+            }
+        }
+    }
+
+    private class MediaProjectionCallback extends MediaProjection.Callback {
+        @Override
+        public void onStop() {
+            changeCaptureStateAndNotify(CaptureState.STOPPED);
+            mMediaProjection = null;
+            if (mVirtualDisplay == null) return;
+            mVirtualDisplay.release();
+            mVirtualDisplay = null;
+        }
+    }
+
+    private final Context mContext;
+
+    private MediaProjection mMediaProjection;
+    private MediaProjectionManager mMediaProjectionManager;
+    private VirtualDisplay mVirtualDisplay;
+    private static final int REQUEST_MEDIA_PROJECTION = 1;
+
+    private Surface mSurface;
+    private ImageReader mImageReader = null;
+    private HandlerThread mThread;
+    private Handler mBackgroundHandler;
+
+    private int mScreenDensity;
+    private int mWidth;
+    private int mHeight;
+    private int mFormat;
+
+    private int mResultCode;
+    private Intent mResultData;
+
+    // Native callback context variable.
+    private final long mNativeScreenCaptureMachineAndroid;
+
+    private static enum CaptureState { ATTACHED, ALLOWED, STARTED, STOPPING, STOPPED }
+    private CaptureState mCaptureState = CaptureState.STOPPED;
+    private final Object mCaptureStateLock = new Object();
+
+    private static final String TAG = "ScreenCaptureMachine";
+
+    ScreenCapture(Context context, long nativeScreenCaptureMachineAndroid) {
+        mContext = context;
+        mNativeScreenCaptureMachineAndroid = nativeScreenCaptureMachineAndroid;
+
+        Activity activity = ApplicationStatus.getLastTrackedFocusedActivity();
+        if (activity == null) {
+            Log.e(TAG, "activity is null");
+            return;
+        }
+
+        FragmentManager fragmentManager = activity.getFragmentManager();
+        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
+        fragmentTransaction.add(this, "screencapture");
+
+        try {
+            fragmentTransaction.commit();
+        } catch (RuntimeException e) {
+            Log.e(TAG, "ScreenCaptureExcaption " + e);
+        }
+
+        DisplayMetrics metrics = new DisplayMetrics();
+        Display display = activity.getWindowManager().getDefaultDisplay();
+        display.getMetrics(metrics);
+        mScreenDensity = metrics.densityDpi;
+    }
+
+    // Factory method.
+    @CalledByNative
+    static ScreenCapture createScreenCaptureMachine(
+            Context context, long nativeScreenCaptureMachineAndroid) {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
+            return new ScreenCapture(context, nativeScreenCaptureMachineAndroid);
+        }
+        return null;
+    }
+
+    @Override
+    public void onAttach(Context context) {
+        super.onAttach(context);
+        Log.d(TAG, "onAttach");
+        changeCaptureStateAndNotify(CaptureState.ATTACHED);
+    }
+
+    // This method was deprecated in API level 23 by onAttach(Context).
+    // TODO(braveyao): remove this method after the minSdkVersion of chrome is 23,
+    // https://crbug.com/614172.
+    @SuppressWarnings("deprecation")
+    @Override
+    public void onAttach(Activity activity) {
+        super.onAttach(activity);
+        Log.d(TAG, "onAttach");
+        changeCaptureStateAndNotify(CaptureState.ATTACHED);
+    }
+
+    @Override
+    public void onDetach() {
+        super.onDetach();
+        Log.d(TAG, "onDetach");
+        stopCapture();
+    }
+
+    @CalledByNative
+    public boolean startPrompt(int width, int height) {
+        Log.d(TAG, "startPrompt");
+        synchronized (mCaptureStateLock) {
+            while (mCaptureState != CaptureState.ATTACHED) {
+                try {
+                    mCaptureStateLock.wait();
+                } catch (InterruptedException ex) {
+                    Log.e(TAG, "ScreenCaptureException: " + ex);
+                }
+            }
+        }
+
+        mWidth = width;
+        mHeight = height;
+
+        mMediaProjectionManager = (MediaProjectionManager) mContext.getSystemService(
+                Context.MEDIA_PROJECTION_SERVICE);
+        if (mMediaProjectionManager == null) {
+            Log.e(TAG, "mMediaProjectionManager is null");
+            return false;
+        }
+
+        try {
+            startActivityForResult(
+                    mMediaProjectionManager.createScreenCaptureIntent(), REQUEST_MEDIA_PROJECTION);
+        } catch (android.content.ActivityNotFoundException e) {
+            Log.e(TAG, "ScreenCaptureException " + e);
+            return false;
+        }
+        return true;
+    }
+
+    @Override
+    public void onActivityResult(int requestCode, int resultCode, Intent data) {
+        if (requestCode != REQUEST_MEDIA_PROJECTION) return;
+
+        if (resultCode == Activity.RESULT_OK) {
+            mResultCode = resultCode;
+            mResultData = data;
+            changeCaptureStateAndNotify(CaptureState.ALLOWED);
+        }
+        nativeOnActivityResult(
+                mNativeScreenCaptureMachineAndroid, resultCode == Activity.RESULT_OK);
+    }
+
+    @CalledByNative
+    public void startCapture() {
+        Log.d(TAG, "startCapture");
+        synchronized (mCaptureStateLock) {
+            if (mCaptureState != CaptureState.ALLOWED) {
+                Log.e(TAG, "startCapture() invoked without user permission.");
+                return;
+            }
+        }
+        mMediaProjection = mMediaProjectionManager.getMediaProjection(mResultCode, mResultData);
+        if (mMediaProjection == null) {
+            Log.e(TAG, "mMediaProjection is null");
+            return;
+        }
+        mMediaProjection.registerCallback(new MediaProjectionCallback(), null);
+
+        mThread = new HandlerThread("ScreenCapture");
+        mThread.start();
+        mBackgroundHandler = new Handler(mThread.getLooper());
+
+        // On Android M and above, YUV420 is prefered. Some Android L devices will silently
+        // fail with YUV420, so keep with RGBA_8888 on L.
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
+            mFormat = PixelFormat.RGBA_8888;
+        } else {
+            mFormat = ImageFormat.YUV_420_888;
+        }
+        createImageReaderWithFormat(mFormat);
+        createVirtualDisplay();
+
+        changeCaptureStateAndNotify(CaptureState.STARTED);
+    }
+
+    @CalledByNative
+    public void stopCapture() {
+        Log.d(TAG, "stopCapture");
+        synchronized (mCaptureStateLock) {
+            if (mMediaProjection != null && mCaptureState == CaptureState.STARTED) {
+                mMediaProjection.stop();
+                changeCaptureStateAndNotify(CaptureState.STOPPING);
+            }
+
+            while (mCaptureState != CaptureState.STOPPED) {
+                try {
+                    mCaptureStateLock.wait();
+                } catch (InterruptedException ex) {
+                    Log.e(TAG, "ScreenCaptureEvent: " + ex);
+                }
+            }
+        }
+    }
+
+    private void createImageReaderWithFormat(int format) {
+        final int maxImages = 2;
+        mImageReader = ImageReader.newInstance(mWidth, mHeight, format, maxImages);
+        mSurface = mImageReader.getSurface();
+        final CrImageReaderListener imageReaderListener = new CrImageReaderListener();
+        mImageReader.setOnImageAvailableListener(imageReaderListener, mBackgroundHandler);
+    }
+
+    private void createVirtualDisplay() {
+        mVirtualDisplay = mMediaProjection.createVirtualDisplay("ScreenCapture", mWidth, mHeight,
+                mScreenDensity, DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR, mSurface, null,
+                null);
+    }
+
+    private void changeCaptureStateAndNotify(CaptureState state) {
+        synchronized (mCaptureStateLock) {
+            mCaptureState = state;
+            mCaptureStateLock.notifyAll();
+        }
+    }
+
+    // Method for ScreenCapture implementations to call back native code.
+    private native void nativeOnRGBAFrameAvailable(long nativeScreenCaptureMachineAndroid,
+            ByteBuffer buf, int left, int top, int cropWidth, int cropHeight, int rowStride,

[miu, 2016/06/08 21:06:50]

nit: It's sufficient to just call these width and height instead of cropWidth
and cropHeight (since the rowStride allows the calculation to the byte offset
per row).

[braveyao, 2016/06/08 22:49:50]

Done.

+            long timestamp);
+    // Method for ScreenCapture implementations to call back native code.
+    private native void nativeOnI420FrameAvailable(long nativeScreenCaptureMachineAndroid,
+            ByteBuffer yBuffer, int yStride, ByteBuffer uBuffer, ByteBuffer vBuffer,
+            int uvRowStride, int uvPixelStride, int left, int top, int cropWidth, int cropHeight,

[miu, 2016/06/08 21:06:50]

nit (ditto): s/crop//

[braveyao, 2016/06/08 22:49:50]

Done.

+            long timestamp);
+    // Method for ScreenCapture implementations to call back native code.
+    private native void nativeOnActivityResult(
+            long nativeScreenCaptureMachineAndroid, boolean result);
+}