commit 50eef8316cbe035f3bef98b757edb35669a3466e
author Mark <markchien@google.com> Tue Sep 19 06:56:14 2023 +0000
committer Mark <markchien@google.com> Thu Oct 26 09:31:18 2023 +0000
tree 6a220d3a15a2616378b551007b237a25fbd06f04
parent 5cc386bdef581c82265cb134bc25c5d46531b043

SyncSM8.1 always call transitionTo under processMessage

As state transitions always occur after a message has been processed,
calling transitionTo only under processMessage makes the flow easier
to understand and less error-prone.

The risk of this change is very minimal since it is only about
handling the error, but tethering will stop regardless.

Test: atest TetheringTests

Change-Id: I56c6cf6cc989464ee84a8333ac131afc808a3d95

Tethering/src/android/net/ip/IpServer.java

diff --git a/Tethering/src/android/net/ip/IpServer.java b/Tethering/src/android/net/ip/IpServer.java
index 6063526..c04d0dc 100644
--- a/Tethering/src/android/net/ip/IpServer.java
+++ b/Tethering/src/android/net/ip/IpServer.java
@@ -237,6 +237,7 @@
     public static final int CMD_NEW_PREFIX_REQUEST          = BASE_IPSERVER + 12;
     // request from PrivateAddressCoordinator to restart tethering.
     public static final int CMD_NOTIFY_PREFIX_CONFLICT      = BASE_IPSERVER + 13;
+    public static final int CMD_SERVICE_FAILED_TO_START     = BASE_IPSERVER + 14;
 
     private final State mInitialState;
     private final State mLocalHotspotState;
@@ -510,7 +511,8 @@
 
         private void handleError() {
             mLastError = TETHER_ERROR_DHCPSERVER_ERROR;
-            transitionTo(mInitialState);
+            sendMessageAtFrontOfQueueToAsyncSM(CMD_SERVICE_FAILED_TO_START,
+                    TETHER_ERROR_DHCPSERVER_ERROR);
         }
     }
 
@@ -1120,7 +1122,14 @@
             startServingInterface();
 
             if (mLastError != TETHER_ERROR_NO_ERROR) {
-                transitionTo(mInitialState);
+                // This will transition to InitialState right away, regardless of whether any
+                // message is already waiting in the StateMachine queue (including maybe some
+                // message to go to InitialState). InitialState will then process any pending
+                // message (and generally ignores them). It is difficult to know for sure whether
+                // this is correct in all cases, but this is equivalent to what IpServer was doing
+                // in previous versions of the mainline module.
+                // TODO : remove this after migrating to the Sync StateMachine.
+                sendMessageAtFrontOfQueueToAsyncSM(CMD_SERVICE_FAILED_TO_START, mLastError);
             }
 
             if (DBG) Log.d(TAG, getStateString(mDesiredInterfaceState) + " serve " + mIfaceName);
@@ -1210,6 +1219,9 @@
                     mCallback.requestEnableTethering(mInterfaceType, false /* enabled */);
                     transitionTo(mWaitingForRestartState);
                     break;
+                case CMD_SERVICE_FAILED_TO_START:
+                    mLog.e("start serving fail, error: " + message.arg1);
+                    transitionTo(mInitialState);
                 default:
                     return false;
             }