Fix the "onPostExecute executed even when cancelled" issue

Renamed onPostExecute to onSuccess and made sure it won't called
if a task is cancelled in time.

Also removed isCancelled().  To implement it right we should make sure
that onPostExecute() isn't finished when setting mCancelled, but it's a bit
of a pain to implement right, and we don't really have to use it.

Change-Id: I3a0baf504506ffc4952a5553f7098a8415842fa3

emailcommon/src/com/android/emailcommon/utility/EmailAsyncTask.java

@@ -29,9 +29,11 @@ import java.util.concurrent.Executor;
  * Modeled after {@link AsyncTask}; the basic usage is the same, with extra features:
  * - Bulk cancellation of multiple tasks.  This is mainly used by UI to cancel pending tasks
  *   in onDestroy() or similar places.
- * - More features to come...
+ * - Instead of {@link AsyncTask#onPostExecute}, it has {@link #onSuccess(Object)}, as the
+ *   regular {@link AsyncTask#onPostExecute} is a bit hard to predict when it'll be called and
+ *   whel it won't.
  *
- * Note this class isn't 100% compatible to the regular {@link AsyncTask}, e.g. it lacks
+ * Note this class is missing some of the {@link AsyncTask} features, e.g. it lacks
  * {@link AsyncTask#onProgressUpdate}.  Add these when necessary.
  */
 public abstract class EmailAsyncTask<Params, Progress, Result> {
@@ -125,11 +127,16 @@ public abstract class EmailAsyncTask<Params, Progress, Result> {
         @Override
         public void onPostExecute(Result2 result) {
             mOwner.unregisterSelf();
-            mOwner.onPostExecute(result);
+            if (mOwner.mCancelled) {
+                mOwner.onCancelled(result);
+            } else {
+                mOwner.onSuccess(result);
+            }
         }
     }
 
     private final InnerTask<Params, Progress, Result> mInnerTask;
+    private volatile boolean mCancelled;
 
     public EmailAsyncTask(Tracker tracker) {
         mTracker = tracker;
@@ -150,16 +157,23 @@ public abstract class EmailAsyncTask<Params, Progress, Result> {
 
 
     /** @see AsyncTask#cancel(boolean) */
-    public final boolean cancel(boolean mayInterruptIfRunning) {
-        return mInnerTask.cancel(mayInterruptIfRunning);
+    public final void cancel(boolean mayInterruptIfRunning) {
+        mCancelled = true;
+        mInnerTask.cancel(mayInterruptIfRunning);
     }
 
     /** @see AsyncTask#onCancelled */
     protected void onCancelled(Result result) {
     }
 
-    /** @see AsyncTask#onPostExecute */
-    protected void onPostExecute(Result result) {
+    /**
+     * Similar to {@link AsyncTask#onPostExecute}, but this will never be executed if
+     * {@link #cancel(boolean)} has been called before its execution, even if
+     * {@link #doInBackground(Object...)} has completed when cancelled.
+     *
+     * @see AsyncTask#onPostExecute
+     */
+    protected void onSuccess(Result result) {
     }
 
     /**
@@ -246,11 +260,6 @@ public abstract class EmailAsyncTask<Params, Progress, Result> {
         return mInnerTask.get();
     }
 
-    /** @see AsyncTask#isCancelled */
-    public final boolean isCancelled() {
-        return mInnerTask.isCancelled();
-    }
-
     /* package */ final Result callDoInBackgroundForTest(Params... params) {
         return mInnerTask.doInBackground(params);
     }

src/com/android/email/activity/EmailActivity.java

@@ -509,7 +509,7 @@ public class EmailActivity extends Activity implements View.OnClickListener, Fra
                     }
 
                     @Override
-                    protected void onPostExecute(String accountName) {
+                    protected void onSuccess(String accountName) {
                         String message =
                             MessagingExceptionStrings.getErrorString(EmailActivity.this, result);
                         if (!TextUtils.isEmpty(accountName)) {

src/com/android/email/activity/MailboxFinder.java

@@ -200,7 +200,7 @@ public class MailboxFinder {
         }
 
         @Override
-        protected void onPostExecute(Long mailboxId) {
+        protected void onSuccess(Long mailboxId) {
             switch (mResult) {
                 case RESULT_ACCOUNT_SECURITY_HOLD:
                     Log.w(Logging.LOG_TAG, "MailboxFinder: Account security hold.");

src/com/android/email/activity/MailboxListFragment.java

@@ -673,7 +673,7 @@ public class MailboxListFragment extends ListFragment implements OnItemClickList
         }
 
         @Override
-        protected void onPostExecute(Long[] result) {
+        protected void onSuccess(Long[] result) {
             mCallback.onResult(result[0], result[1], result[2]);
         }
     }

src/com/android/email/activity/MessageCompose.java

@@ -984,7 +984,7 @@ public class MessageCompose extends Activity implements OnClickListener, OnFocus
         }
 
         @Override
-        protected void onPostExecute(Object[] results) {
+        protected void onSuccess(Object[] results) {
             if ((results == null) || (results.length != 3)) {
                 mCallback.onLoadFailed();
                 return;
@@ -1023,7 +1023,7 @@ public class MessageCompose extends Activity implements OnClickListener, OnFocus
             }
 
             @Override
-            protected void onPostExecute(Attachment[] attachments) {
+            protected void onSuccess(Attachment[] attachments) {
                 if (attachments == null) {
                     attachments = new Attachment[0];
                 }
@@ -1296,7 +1296,7 @@ public class MessageCompose extends Activity implements OnClickListener, OnFocus
         }
 
         @Override
-        protected void onPostExecute(Long draftId) {
+        protected void onSuccess(Long draftId) {
             // Note that send or save tasks are always completed, even if the activity
             // finishes earlier.
             sActiveSaveTasks.remove(mTaskId);

src/com/android/email/activity/MessageFileView.java

@@ -113,7 +113,7 @@ public class MessageFileView extends Activity implements MessageViewFragmentBase
         }
 
         @Override
-        protected void onPostExecute(String filename) {
+        protected void onSuccess(String filename) {
             if (filename == null) {
                 return;
             }

src/com/android/email/activity/MessageList.java

@@ -49,7 +49,7 @@ public class MessageList extends Activity {
             }
 
             @Override
-            protected void onPostExecute(Long accountId) {
+            protected void onSuccess(Long accountId) {
                 if ((accountId == null) || (accountId == Account.NO_ACCOUNT)) {
                     // Account deleted?
                     Utility.showToast(me, R.string.toast_account_not_found);

src/com/android/email/activity/MessageListFragment.java

@@ -761,7 +761,7 @@ public class MessageListFragment extends ListFragment
         }
 
         @Override
-        protected void onPostExecute(Integer type) {
+        protected void onSuccess(Integer type) {
             if (type == null) {
                 return;
             }

src/com/android/email/activity/MessageOrderManager.java

@@ -284,7 +284,7 @@ public class MessageOrderManager {
         }
 
         @Override
-        protected void onPostExecute(Cursor cursor) {
+        protected void onSuccess(Cursor cursor) {
             onCursorOpenDone(cursor);
         }
     }

src/com/android/email/activity/MessageViewFragmentBase.java

@@ -858,7 +858,7 @@ public abstract class MessageViewFragmentBase extends Fragment implements View.O
                     return null;
                 }
                 @Override
-                protected void onPostExecute(Void result) {
+                protected void onSuccess(Void result) {
                     // If the timeout completes and the attachment has not loaded, show cancel
                     if (!attachment.loaded) {
                         attachment.cancelButton.setVisibility(View.VISIBLE);
@@ -1058,7 +1058,7 @@ public abstract class MessageViewFragmentBase extends Fragment implements View.O
         }
 
         @Override
-        protected void onPostExecute(Message message) {
+        protected void onSuccess(Message message) {
             if (message == null) {
                 resetView();
                 mCallback.onMessageNotExists();
@@ -1092,7 +1092,7 @@ public abstract class MessageViewFragmentBase extends Fragment implements View.O
         }
 
         @Override
-        protected void onPostExecute(Message message) {
+        protected void onSuccess(Message message) {
             if (message == null || message.mMailboxKey != mMessage.mMailboxKey) {
                 // Message deleted or moved.
                 mCallback.onMessageNotExists();
@@ -1153,7 +1153,7 @@ public abstract class MessageViewFragmentBase extends Fragment implements View.O
         }
 
         @Override
-        protected void onPostExecute(String[] results) {
+        protected void onSuccess(String[] results) {
             if (results == null) {
                 if (mErrorLoadingMessageBody) {
                     Utility.showToast(getActivity(), R.string.error_loading_message_body);
@@ -1185,7 +1185,7 @@ public abstract class MessageViewFragmentBase extends Fragment implements View.O
         }
 
         @Override
-        protected void onPostExecute(Attachment[] attachments) {
+        protected void onSuccess(Attachment[] attachments) {
             try {
                 if (attachments == null) {
                     return;
@@ -1903,7 +1903,7 @@ public abstract class MessageViewFragmentBase extends Fragment implements View.O
         }
 
         @Override
-        protected void onPostExecute(Bitmap result) {
+        protected void onSuccess(Bitmap result) {
             if (result == null) {
                 return;
             }

src/com/android/email/activity/UIControllerTwoPane.java

@@ -741,7 +741,7 @@ class UIControllerTwoPane extends UIControllerBase implements
          * Do the actual refresh.
          */
         @Override
-        protected void onPostExecute(Boolean isCurrentMailboxRefreshable) {
+        protected void onSuccess(Boolean isCurrentMailboxRefreshable) {
             if (isCurrentMailboxRefreshable == null) {
                 return;
             }

src/com/android/email/activity/Welcome.java

@@ -344,7 +344,7 @@ public class Welcome extends Activity {
         }
 
         @Override
-        protected void onPostExecute(Void noResult) {
+        protected void onSuccess(Void noResult) {
             final Activity activity = Welcome.this;
 
             if (mStartAccountSetup) {

src/com/android/email/activity/setup/AccountSettingsEditQuickResponsesFragment.java

@@ -180,7 +180,7 @@ public class AccountSettingsEditQuickResponsesFragment extends Fragment
         }
 
         @Override
-        protected void onPostExecute(QuickResponse[] quickResponseItems) {
+        protected void onSuccess(QuickResponse[] quickResponseItems) {
             ArrayAdapter<QuickResponse> adapter;
             if (mIsEditable) {
                     adapter = new ArrayAdapterWithButtons(

tests/src/com/android/email/activity/FindParentMailboxTaskTest.java

@@ -291,7 +291,7 @@ public class FindParentMailboxTaskTest extends AndroidTestCase {
                 highlightedMailboxId, result);
 
         // Can't execute an async task on the test thread, so emulate execution...
-        task.onPostExecute(task.doInBackground((Void[]) null));
+        task.onSuccess(task.doInBackground((Void[]) null));
 
         assertEquals("parent", expectedNextParent, result.mNextParentMailboxId);
         assertEquals("highlighted", expectedNextHighlighted, result.mNextHighlightedMailboxId);

tests/src/com/android/emailcommon/utility/EmailAsyncTaskTests.java

@@ -73,8 +73,6 @@ public class EmailAsyncTaskTests extends AndroidTestCase {
         tracker.cancellAllInterrupt();
 
         // Check if they're canceled
-        assertTrue(task2.isCancelled());
-        assertTrue(task4.isCancelled());
         assertEquals(0, tracker.getTaskCountForTest());
     }
 
@@ -137,7 +135,7 @@ public class EmailAsyncTaskTests extends AndroidTestCase {
         }
 
         @Override
-        protected void onPostExecute(String result) {
+        protected void onSuccess(String result) {
             mOnPostExecuteArg = result;
         }
     }