android_webview/glue/java/src/com/android/webview/chromium/DrawGLFunctor.java

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 package com.android.webview.chromium;
   6
   7 import android.graphics.Canvas;
   8 import android.view.View;
   9
  10 import com.android.webview.chromium.WebViewDelegateFactory.WebViewDelegate;
  11
  12 import org.chromium.content.common.CleanupReference;
  13
  14 /**
  15  * Simple Java abstraction and wrapper for the native DrawGLFunctor flow.
  16  * An instance of this class can be constructed, bound to a single view context (i.e. AwContennts)
  17  * and then drawn and detached from the view tree any number of times (using requestDrawGL and
  18  * detach respectively). Then when finished with, it can be explicitly released by calling
  19  * destroy() or will clean itself up as required via finalizer / CleanupReference.
  20  */
  21 class DrawGLFunctor {
  22     private static final String TAG = DrawGLFunctor.class.getSimpleName();
  23
  24     // Pointer to native side instance
  25     private CleanupReference mCleanupReference;
  26     private DestroyRunnable mDestroyRunnable;
  27     private final long mNativeDrawGLFunctor;
  28     private WebViewDelegate mWebViewDelegate;
  29     View mContainerView;
  30
  31     public DrawGLFunctor(long viewContext, WebViewDelegate webViewDelegate) {
  32         mNativeDrawGLFunctor = nativeCreateGLFunctor(viewContext);
  33         mDestroyRunnable = new DestroyRunnable(mNativeDrawGLFunctor);
  34         mCleanupReference = new CleanupReference(this, mDestroyRunnable);
  35         mWebViewDelegate = webViewDelegate;
  36     }
  37
  38     public void destroy() {
  39         detach();
  40         if (mCleanupReference != null) {
  41             mCleanupReference.cleanupNow();
  42             mCleanupReference = null;
  43             mDestroyRunnable = null;
  44             mWebViewDelegate = null;
  45             mContainerView = null;
  46         }
  47     }
  48
  49     public void detach() {
  50         if (mWebViewDelegate != null && mContainerView != null) {
  51             mWebViewDelegate.detachDrawGlFunctor(mContainerView, mNativeDrawGLFunctor);
  52         }
  53     }
  54
  55     public boolean requestDrawGL(Canvas canvas, View containerView, boolean waitForCompletion) {
  56         if (mDestroyRunnable.mNativeDrawGLFunctor == 0) {
  57             throw new RuntimeException("requested DrawGL on already destroyed DrawGLFunctor");
  58         }
  59
  60         if (canvas != null && waitForCompletion) {
  61             throw new IllegalArgumentException(
  62                     "requested a blocking DrawGL with a not null canvas.");
  63         }
  64
  65         if (!mWebViewDelegate.canInvokeDrawGlFunctor(containerView)) {
  66             return false;
  67         }
  68
  69         mContainerView = containerView;
  70
  71         if (canvas == null) {
  72             mWebViewDelegate.invokeDrawGlFunctor(
  73                     containerView, mDestroyRunnable.mNativeDrawGLFunctor, waitForCompletion);
  74             return true;
  75         }
  76
  77         mWebViewDelegate.callDrawGlFunction(canvas, mDestroyRunnable.mNativeDrawGLFunctor);
  78         return true;
  79     }
  80
  81     public static void setChromiumAwDrawGLFunction(long functionPointer) {
  82         nativeSetChromiumAwDrawGLFunction(functionPointer);
  83     }
  84
  85     // Holds the core resources of the class, everything required to correctly cleanup.
  86     // IMPORTANT: this class must not hold any reference back to the outer DrawGLFunctor
  87     // instance, as that will defeat GC of that object.
  88     private static final class DestroyRunnable implements Runnable {
  89         private long mNativeDrawGLFunctor;
  90         DestroyRunnable(long nativeDrawGLFunctor) {
  91             mNativeDrawGLFunctor = nativeDrawGLFunctor;
  92             assert mNativeDrawGLFunctor != 0;
  93         }
  94
  95         // Called when the outer DrawGLFunctor instance has been GC'ed, i.e this is its finalizer.
  96         @Override
  97         public void run() {
  98             assert mNativeDrawGLFunctor != 0;
  99             nativeDestroyGLFunctor(mNativeDrawGLFunctor);
 100             mNativeDrawGLFunctor = 0;
 101         }
 102     }
 103
 104     private static native long nativeCreateGLFunctor(long viewContext);
 105     private static native void nativeDestroyGLFunctor(long functor);
 106     private static native void nativeSetChromiumAwDrawGLFunction(long functionPointer);
 107 }