am 9aa6bd1c: am 717a25dc: Add new ManagedEGLContext class to help apps participate in memory trimming.

* commit '9aa6bd1c34fe3583fe31f283a6415e84fec12567':
  Add new ManagedEGLContext class to help apps participate in memory trimming.

1 files changed, 136 insertions, 0 deletions

diff --git a/opengl/java/android/opengl/ManagedEGLContext.java b/opengl/java/android/opengl/ManagedEGLContext.java
new file mode 100644
index 0000000..d3a3662
--- /dev/null
+++ b/opengl/java/android/opengl/ManagedEGLContext.java
@@ -0,0 +1,136 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.opengl;
+
+import static javax.microedition.khronos.egl.EGL10.EGL_DEFAULT_DISPLAY;
+import static javax.microedition.khronos.egl.EGL10.EGL_NO_DISPLAY;
+
+import java.util.ArrayList;
+
+import javax.microedition.khronos.egl.EGL10;
+import javax.microedition.khronos.egl.EGLContext;
+import javax.microedition.khronos.egl.EGLDisplay;
+
+import android.os.Looper;
+import android.util.Log;
+
+import com.google.android.gles_jni.EGLImpl;
+
+/**
+ * The per-process memory overhead of hardware accelerated graphics can
+ * be quite large on some devices.  For small memory devices, being able to
+ * terminate all EGL contexts so that this graphics driver memory can be
+ * reclaimed can significant improve the overall behavior of the device.  This
+ * class helps app developers participate in releasing their EGL context
+ * when appropriate and possible.
+ * 
+ * <p>To use, simple instantiate this class with the EGLContext you create.
+ * When you have done this, if the device is getting low on memory and all
+ * of the currently created EGL contexts in the process are being managed
+ * through this class, then they will all be asked to terminate through the
+ * call to {@link #onTerminate}.
+ */
+public abstract class ManagedEGLContext {
+    static final String TAG = "ManagedEGLContext";
+
+    static final ArrayList<ManagedEGLContext> sActive
+            = new ArrayList<ManagedEGLContext>();
+
+    final EGLContext mContext;
+
+    /**
+     * Instantiate to manage the given EGLContext.
+     */
+    public ManagedEGLContext(EGLContext context) {
+        mContext = context;
+        synchronized (sActive) {
+            sActive.add(this);
+        }
+    }
+
+    /**
+     * Retrieve the EGLContext being managed by the class.
+     */
+    public EGLContext getContext() {
+        return mContext;
+    }
+
+    /**
+     * Force-terminate the ManagedEGLContext.  This will cause
+     * {@link #onTerminate(EGLContext)} to be called.  You <em>must</em>
+     * call this when destroying the EGLContext, so that the framework
+     * knows to stop managing it.
+     */
+    public void terminate() {
+        execTerminate();
+    }
+
+    void execTerminate() {
+        onTerminate(mContext);
+    }
+
+    /**
+     * Override this method to destroy the EGLContext when appropriate.
+     * <em>Note that this method is always called on the main thread
+     * of the process.</em>  If your EGLContext was created on a different
+     * thread, you will need to implement this method to hand off the work
+     * of destroying the context to that thread.
+     */
+    public abstract void onTerminate(EGLContext context);
+
+    /** @hide */
+    public static boolean doTerminate() {
+        ArrayList<ManagedEGLContext> active;
+
+        if (Looper.getMainLooper() != Looper.myLooper()) {
+            throw new IllegalStateException("Called on wrong thread");
+        }
+
+        synchronized (sActive) {
+            // If there are no active managed contexts, we will not even
+            // try to terminate.
+            if (sActive.size() <= 0) {
+                return false;
+            }
+
+            // Need to check how many EGL contexts are actually running,
+            // to compare with how many we are managing.
+            EGL10 egl = (EGL10) EGLContext.getEGL();
+            EGLDisplay display = egl.eglGetDisplay(EGL_DEFAULT_DISPLAY);
+
+            if (display == EGL_NO_DISPLAY) {
+                Log.w(TAG, "doTerminate failed: no display");
+                return false;
+            }
+
+            if (EGLImpl.getInitCount(display) != sActive.size()) {
+                Log.w(TAG, "doTerminate failed: EGL count is " + EGLImpl.getInitCount(display)
+                        + " but managed count is " + sActive.size());
+                return false;
+            }
+
+            active = new ArrayList<ManagedEGLContext>(sActive);
+            sActive.clear();
+        }
+
+        for (int i=0; i<active.size(); i++) {
+            active.get(i).execTerminate();
+        }
+
+        return true;
+    }
+}