Restore buildLayer()'s old behavior; it's synchronous again
Bug #9193833
Change-Id: I4ee07e65c0a8967f0b55da030ecaad6dfc46136f
diff --git a/libs/hwui/Fence.h b/libs/hwui/Fence.h
new file mode 100644
index 0000000..f175e98
--- /dev/null
+++ b/libs/hwui/Fence.h
@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+
+#ifndef ANDROID_HWUI_FENCE_H
+#define ANDROID_HWUI_FENCE_H
+
+#include <EGL/egl.h>
+#include <EGL/eglext.h>
+
+namespace android {
+namespace uirenderer {
+
+/**
+ * Creating a Fence instance inserts a new sync fence in the OpenGL
+ * commands stream. The caller can then wait for the fence to be signaled
+ * by calling the wait method.
+ */
+class Fence {
+public:
+ enum {
+ /**
+ * Default timeout in nano-seconds for wait()
+ */
+ kDefaultTimeout = 1000000000
+ };
+
+ /**
+ * Inserts a new sync fence in the OpenGL commands stream.
+ */
+ Fence() {
+ mDisplay = eglGetDisplay(EGL_DEFAULT_DISPLAY);
+ if (mDisplay != EGL_NO_DISPLAY) {
+ mFence = eglCreateSyncKHR(mDisplay, EGL_SYNC_FENCE_KHR, NULL);
+ } else {
+ mFence = EGL_NO_SYNC_KHR;
+ }
+ }
+
+ /**
+ * Destroys the fence. Any caller waiting on the fence will be
+ * signaled immediately.
+ */
+ ~Fence() {
+ if (mFence != EGL_NO_SYNC_KHR) {
+ eglDestroySyncKHR(mDisplay, mFence);
+ }
+ }
+
+ /**
+ * Blocks the calling thread until this fence is signaled, or until
+ * <timeout> nanoseconds have passed.
+ *
+ * Returns true if waiting for the fence was successful, false if
+ * a timeout or an error occurred.
+ */
+ bool wait(EGLTimeKHR timeout = kDefaultTimeout) {
+ EGLint waitStatus = eglClientWaitSyncKHR(mDisplay, mFence,
+ EGL_SYNC_FLUSH_COMMANDS_BIT_KHR, timeout);
+ if (waitStatus == EGL_FALSE) {
+ ALOGW("Failed to wait for the fence %#x", eglGetError());
+ }
+ return waitStatus == EGL_CONDITION_SATISFIED_KHR;
+ }
+
+private:
+ EGLDisplay mDisplay;
+ EGLSyncKHR mFence;
+
+}; // class Fence
+
+/**
+ * An AutoFence creates a Fence instance and waits for the fence
+ * to be signaled when the AutoFence is destroyed. This is useful
+ * to automatically wait for a series of OpenGL commands to be
+ * executed. For example:
+ *
+ * void drawAndWait() {
+ * glDrawElements();
+ * AutoFence fence;
+ * }
+ */
+class AutoFence {
+public:
+ AutoFence(EGLTimeKHR timeout = Fence::kDefaultTimeout): mTimeout(timeout) {
+ }
+
+ ~AutoFence() {
+ mFence.wait(mTimeout);
+ }
+
+private:
+ EGLTimeKHR mTimeout;
+ Fence mFence;
+
+}; // class AutoFence
+
+}; // namespace uirenderer
+}; // namespace android
+
+#endif // ANDROID_HWUI_FENCE_H