1 files changed, 41 insertions, 0 deletions
diff --git a/services/core/java/com/android/server/power/ScreenOnBlocker.java b/services/core/java/com/android/server/power/ScreenOnBlocker.java
new file mode 100644
index 0000000..dbbbc6d
--- /dev/null
+++ b/services/core/java/com/android/server/power/ScreenOnBlocker.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2012 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 com.android.server.power;
+
+/**
+ * Low-level screen on blocker mechanism which is used to keep the screen off
+ * or the contents of the screen hidden until the window manager is ready to show new content.
+ */
+interface ScreenOnBlocker {
+    /**
+     * Acquires the screen on blocker.
+     * Prevents the screen from turning on.
+     *
+     * Calls to acquire() nest and must be matched by the same number
+     * of calls to release().
+     */
+    void acquire();
+
+    /**
+     * Releases the screen on blocker.
+     * Allows the screen to turn on.
+     *
+     * It is an error to call release() if the screen on blocker has not been acquired.
+     * The system may crash.
+     */
+    void release();
+}