Merge "SyncSM03: implement state transition logic" into main
diff --git a/Tethering/src/com/android/networkstack/tethering/util/SyncStateMachine.java b/Tethering/src/com/android/networkstack/tethering/util/SyncStateMachine.java
index 5a984c7..cbbbdec 100644
--- a/Tethering/src/com/android/networkstack/tethering/util/SyncStateMachine.java
+++ b/Tethering/src/com/android/networkstack/tethering/util/SyncStateMachine.java
@@ -140,8 +140,8 @@
ensureCorrectThread();
ensureExistingState(initialState);
- mCurrentState = initialState;
mDestState = initialState;
+ performTransitions();
}
/**
@@ -149,6 +149,8 @@
*/
public final void processMessage(int what, int arg1, int arg2, @Nullable Object obj) {
ensureCorrectThread();
+
+ performTransitions();
}
/**
@@ -173,6 +175,65 @@
}
}
+ private void performTransitions() {
+ // 1. Determine the common ancestor state of current/destination states
+ // 2. Invoke state exit list from current state to common ancestor state.
+ // 3. Invoke state enter list from common ancestor state to destState by going
+ // through mEnterStateStack.
+ if (mDestState == mCurrentState) return;
+
+ final StateInfo commonAncestor = getLastActiveAncestor(mStateInfo.get(mDestState));
+
+ executeExitMethods(commonAncestor, mStateInfo.get(mCurrentState));
+ executeEnterMethods(commonAncestor, mStateInfo.get(mDestState));
+ mCurrentState = mDestState;
+ }
+
+ // Null is the root of all states.
+ private StateInfo getLastActiveAncestor(@Nullable final StateInfo start) {
+ if (null == start || start.mActive) return start;
+
+ return getLastActiveAncestor(mStateInfo.get(start.parent));
+ }
+
+ // Call the exit method from current state to common ancestor state.
+ // Both the commonAncestor and exitingState StateInfo can be null because null is the ancestor
+ // of all states.
+ // For example: When transitioning from state1 to state2, the
+ // executeExitMethods(commonAncestor, exitingState) function will be called twice, once with
+ // null and state1 as the argument, and once with null and null as the argument.
+ // root
+ // | \
+ // current <- state1 state2 -> destination
+ private void executeExitMethods(@Nullable StateInfo commonAncestor,
+ @Nullable StateInfo exitingState) {
+ if (commonAncestor == exitingState) return;
+
+ if (mDbg) Log.d(mName, exitingState.state + " exit()");
+ exitingState.state.exit();
+ exitingState.mActive = false;
+ executeExitMethods(commonAncestor, mStateInfo.get(exitingState.parent));
+ }
+
+ // Call the enter method from common ancestor state to destination state.
+ // Both the commonAncestor and enteringState StateInfo can be null because null is the ancestor
+ // of all states.
+ // For example: When transitioning from state1 to state2, the
+ // executeEnterMethods(commonAncestor, enteringState) function will be called twice, once with
+ // null and state2 as the argument, and once with null and null as the argument.
+ // root
+ // | \
+ // current <- state1 state2 -> destination
+ private void executeEnterMethods(@Nullable StateInfo commonAncestor,
+ @Nullable StateInfo enteringState) {
+ if (enteringState == commonAncestor) return;
+
+ executeEnterMethods(commonAncestor, mStateInfo.get(enteringState.parent));
+ if (mDbg) Log.d(mName, enteringState.state + " enter()");
+ enteringState.state.enter();
+ enteringState.mActive = true;
+ }
+
private void ensureCorrectThread() {
if (!mMyThread.equals(Thread.currentThread())) {
throw new IllegalStateException("Called from wrong thread");