DialogSurfaceHolder implementation.

media/base/android/java/src/org/chromium/media/DialogSurfaceHolder.java

+// 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.app.Dialog;
+import android.content.Context;
+import android.os.Handler;
+import android.os.IBinder;
+import android.view.Gravity;
+import android.view.Surface;
+import android.view.SurfaceHolder;
+import android.view.Window;
+import android.view.WindowManager;
+
+import org.chromium.base.Log;
+
+/**
+ * Provide access to Dialog-based Surfaces.  It is unlikely that you want to
+ * use this class directly.  Instead, use the native wrappers for it in
+ * dialog_surface_holder.h .  If you must use these from java, then it's likely
+ * that you should be using IDialogSurfaceHolder instead.
+ *
+ * There are two threads involved, which we call "primary" and "looper".  The
+ * primary thread is the one that native uses to talk to us, such as the gpu
+ * main thread.  All calls to us from native must be on this thread.
+ *
+ * Note that this class may run in the browser or gpu process, depending on
+ * whether we want the gpu process to have the activity window token or not.
+ *
+ * The wrapper class (DialogSurfaceHolderWrapper) always runs locally with
+ * the JNI code that uses it, probably in the gpu process.
+ *
+ * The looper thread is a separate thread which has the looper for the dialogs
+ * that we create.  We may call into native on that thread.  Note that the
+ * native side handles the resulting race conditions.
+ */
+class DialogSurfaceHolder extends IDialogSurfaceHolder.Stub {
+    private static final String TAG = "cr_media";
+
+    /**
+     * Call back into native with a message about our state.  This can be called
+     * on any thread.  It's okay if it refers to a native object that no longer
+     * exists; we can't really avoid it.  The native side handles it.
+     *
+     * IMPORTANT: Do not call this with mLock held.  Expect that the callback
+     * may call us.
+     */
+    private final IDialogSurfaceCallback mCallback;
+    private final Handler mHandler;
+    private final Context mContext;
+    private final int mRendererPid;
+    private final int mRenderFrameId;
+
+    // Callback operations.
+    // These must match dialog_surface.h .
+    private static final int OP_CREATED = 0;
+    private static final int OP_DESTROYED = 1;
+
+    private DialogSurfaceManager mOwner;
+
+    ////// Either thread, protected by mLock
+    private final Object mLock = new Object();
+    private Dialog mDialog;
+    private boolean mReleased;
+    private Surface mSurface;
+
+    /**
+     * Called from primary thread.
+     * Note that (pid, frameId) might be replaced by a token.
+     * @param rendererPid pid of owning renderer process
+     * @param renderFrameId render frame ID owned by Pid
+     * @param context Context that we use.
+     * @param owner Owning manager that we'll notify on release().
+     * @param handler handler for a thread with a looper.
+     * @param callback callback object to notify about state changes.
+     * @param x initial x position in chrome compositor (not screen) coords.
+     * @param y initial y position in chrome compositor (not screen) coords.
+     * @param width initial width.
+     * @param height initial height.
+     */
+    public DialogSurfaceHolder(int rendererPid, int renderFrameId, Context context,
+            DialogSurfaceManager owner, Handler handler, IDialogSurfaceCallback callback, int x,
+            int y, int width, int height) {
+        mRendererPid = rendererPid;
+        mRenderFrameId = renderFrameId;
+        mContext = context;
+        mOwner = owner;
+        mHandler = handler;
+        mCallback = callback;
+
+        mReleased = false;
+
+        scheduleCreateDialog(x, y, width, height);
+    }
+
+    // Note that the native wrapper should call release() anyway on destruction.
+    protected void finalize() throws Throwable {
+        synchronized (mLock) {
+            if (!mReleased) {
+                Log.w(TAG, "Not released before finalization, releasing now");
+            }
+        }
+        release();
+        super.finalize();
+    }
+
+    /**
+     * Release the underlying surface, and generally clean up.
+     */
+    @Override
+    public void release() {
+        synchronized (mLock) {
+            if (!mReleased) mOwner.notifyReleased();
+            mOwner = null;
+
+            // Note that we can't prevent callbacks; they must execute without
+            // the lock held so that the callback can do things that requires
+            // the lock (e.g., GetSurface).  However, the native side handles
+            // races with deleted objects, not us.
+
+            // Prevent any in-flight create from succeeding, and hide any dialog
+            // that we currently have.
+            mReleased = true;
+            if (mDialog != null) {
+                Runnable r = new Runnable() {
+                    @Override
+                    public void run() {
+                        synchronized (mLock) {
+                            mDialog.dismiss();
+                            mDialog = null;
+                        }
+                    }
+                };
+                mHandler.post(r);
+            }
+        }
+    }
+
+    @Override
+    public Surface getSurface() {
+        synchronized (mLock) {
+            return mSurface;
+        }
+    }
+
+    @Override
+    public void scheduleLayoutSurface(final int x, final int y, final int width, final int height) {
+        synchronized (mLock) {
+            final Dialog dialog = mDialog;
+            // Note that mDialog might be replaced, but that means that
+            // somebody called scheduleLayoutSurface while a create was pending
+            // before they got notification that the surface was ready.
+
+            if (dialog == null) return;
+
+            Runnable r = new Runnable() {
+                @Override
+                public void run() {
+                    layoutDialog(dialog, x, y, width, height);
+                }
+            };
+
+            mHandler.post(r);
+        }
+    }
+
+    /**
+     * Callbacks for finding out about the Dialog's Surface.
+     * These happen on the looper thread.
+     */
+    private class Callbacks implements SurfaceHolder.Callback2 {
+        @Override
+        public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {}
+
+        @Override
+        public void surfaceCreated(SurfaceHolder holder) {
+            synchronized (mLock) {
+                mSurface = holder.getSurface();
+            }
+
+            try {
+                mCallback.onCallback(OP_CREATED);
+            } catch (Exception e) {
+                Log.e(TAG, "SurfaceCreated: callback failed: " + e);
+                release();
+            }
+        }
+
+        @Override
+        public void surfaceDestroyed(SurfaceHolder holder) {
+            synchronized (mLock) {
+                mSurface = null;
+            }
+
+            try {
+                mCallback.onCallback(OP_DESTROYED);
+            } catch (Exception e) {
+                Log.e(TAG, "SurfaceDestroyed: callback failed: " + e);
+                release();
+            }
+        }
+
+        @Override
+        public void surfaceRedrawNeeded(SurfaceHolder holder) {}
+    }
+
+    /**
+     * Schedule creation of the dialog on our looper thread.  Sets mThread
+     * asynchronously.  If release() occurs before then, then the dialog will
+     * not be created.
+     */
+    private void scheduleCreateDialog(final int x, final int y, final int width, final int height) {
+        synchronized (mLock) {
+            mDialog = null;
+        }
+
+        Runnable r = new Runnable() {
+            @Override
+            public void run() {
+                Dialog dialog = new Dialog(mContext, android.R.style.Theme_NoDisplay);
+                dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
+                dialog.setCancelable(false);
+                layoutDialog(dialog, x, y, width, height);
+                dialog.getWindow().takeSurface(new Callbacks());
+                synchronized (mLock) {
+                    // If we've been released in the interim, then stop here.
+                    if (mReleased) return;
+
+                    dialog.show();
+                    mDialog = dialog;
+                }
+            }
+        }; // new Runnable
+
+        // Post it to our dedicated thread.
+        mHandler.post(r);
+    }
+
+    /**
+     * Layout the dialog on the current thread.  This should be called from the
+     * looper thread.
+     * Call scheduleLayoutDialog from anywhere else.
+     */
+    private void layoutDialog(Dialog dialog, int x, int y, int width, int height) {
+        // Rather than using getAttributes, we just create them from scratch.
+        // The default dialog attributes aren't what we want.
+        WindowManager.LayoutParams layoutParams = new WindowManager.LayoutParams();
+
+        // TODO(liberato): adjust for CompositorView screen location here if we
+        // want to support non-full screen use cases.
+        layoutParams.x = x;
+        layoutParams.y = y;
+        layoutParams.width = width;
+        layoutParams.height = height;
+        layoutParams.gravity = Gravity.TOP | Gravity.LEFT;
+
+        // Use a media surface, which is what SurfaceView uses by default.  For
+        // debugging overlay drawing, consider using TYPE_APPLICATION_PANEL to
+        // move the dialog over the CompositorView.
+        layoutParams.type = WindowManager.LayoutParams.TYPE_APPLICATION_MEDIA;
+
+        layoutParams.flags = WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL
+                | WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE
+                | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
+                | WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS;
+
+        // Don't set FLAG_SCALED.  in addition to not being sure what it does
+        // (SV uses it), it also causes a crash in WindowManager when we hide
+        // (not dismiss), navigate, and/or exit the app without hide/dismiss.
+        // There's a missing null check in WindowManagerService.java@3170
+        // on M MR2.  To repro, change dimiss() to hide(), bring up a SV, and
+        // navigate away or press home.
+
+        // Turn off the position animation, so that it doesn't animate from one
+        // position to the next.
+        try {
+            int currentFlags =
+                    (Integer) layoutParams.getClass().getField("privateFlags").get(layoutParams);
+            layoutParams.getClass()
+                    .getField("privateFlags")
+                    .set(layoutParams, currentFlags | 0x00000040);
+            // It would be nice to just catch Exception, but findbugs doesn't
+            // allow it.  If we cannot set the flag, then that's okay too.
+        } catch (NoSuchFieldException e) {
+        } catch (NullPointerException e) {
+        } catch (SecurityException e) {
+        } catch (IllegalAccessException e) {
+        } catch (IllegalArgumentException e) {
+        } catch (ExceptionInInitializerError e) {
+        }
+
+        layoutParams.token = getWindowToken();
+
+        dialog.getWindow().setAttributes(layoutParams);
+    }
+
+    private IBinder getWindowToken() {
+        IBinder token = null;
+        try {
+            token = mOwner.getMapper().getWindowToken(mRendererPid, mRenderFrameId);
+        } catch (Exception e) {
+        }
+        return token;
+    }
+}