1 files changed, 65 insertions, 0 deletions
diff --git a/include/media/stagefright/foundation/AHierarchicalStateMachine.h b/include/media/stagefright/foundation/AHierarchicalStateMachine.h
new file mode 100644
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+++ b/include/media/stagefright/foundation/AHierarchicalStateMachine.h
@@ -0,0 +1,65 @@
+/*
+ * 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.
+ */
+
+#ifndef A_HIERARCHICAL_STATE_MACHINE_H_
+
+#define A_HIERARCHICAL_STATE_MACHINE_H_
+
+#include <media/stagefright/foundation/AHandler.h>
+
+namespace android {
+
+struct AState : public RefBase {
+    AState(const sp<AState> &parentState = NULL);
+
+    sp<AState> parentState();
+
+protected:
+    virtual ~AState();
+
+    virtual void stateEntered();
+    virtual void stateExited();
+
+    virtual bool onMessageReceived(const sp<AMessage> &msg) = 0;
+
+private:
+    friend struct AHierarchicalStateMachine;
+
+    sp<AState> mParentState;
+
+    DISALLOW_EVIL_CONSTRUCTORS(AState);
+};
+
+struct AHierarchicalStateMachine : public AHandler {
+    AHierarchicalStateMachine();
+
+protected:
+    virtual ~AHierarchicalStateMachine();
+
+    virtual void onMessageReceived(const sp<AMessage> &msg);
+
+    // Only to be called in response to a message.
+    void changeState(const sp<AState> &state);
+
+private:
+    sp<AState> mState;
+
+    DISALLOW_EVIL_CONSTRUCTORS(AHierarchicalStateMachine);
+};
+
+}  // namespace android
+
+#endif  // A_HIERARCHICAL_STATE_MACHINE_H_