Use the CursorWithExtras pattern for the message list.

This will make the message list a lot snappier.

We were using two different loaders for the message list; one is to load
the meta information and the other to load the actual message list.

Unify them using the CursorWithExtras pattern.

Change-Id: I02957bbca1b1fb74ca6eca14ad2535dfdbf03a5a

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

@@ -21,7 +21,6 @@ import com.android.email.Email;
 import com.android.email.NotificationController;
 import com.android.email.R;
 import com.android.email.RefreshManager;
-import com.android.email.data.MailboxAccountLoader;
 import com.android.email.provider.EmailProvider;
 import com.android.emailcommon.Logging;
 import com.android.emailcommon.provider.EmailContent.Account;
@@ -92,8 +91,7 @@ public class MessageListFragment extends ListFragment
     private static final String BUNDLE_KEY_SELECTED_MESSAGE_ID
             = "messageListFragment.state.listState.selected_message_id";
 
-    private static final int LOADER_ID_MAILBOX_LOADER = 1;
+    private static final int LOADER_ID_MESSAGES_LOADER = 1;
-    private static final int LOADER_ID_MESSAGES_LOADER = 2;
 
     /** Argument name(s) */
     private static final String ARG_ACCOUNT_ID = "accountId";
@@ -1149,48 +1147,7 @@ public class MessageListFragment extends ListFragment
 
         // Start loading...
         final LoaderManager lm = getLoaderManager();
-        lm.initLoader(LOADER_ID_MAILBOX_LOADER, null, new MailboxAccountLoaderCallback());
+        lm.initLoader(LOADER_ID_MESSAGES_LOADER, null, new MessagesLoaderCallback());
-    }
-
-    /**
-     * Loader callbacks for {@link MailboxAccountLoader}.
-     */
-    private class MailboxAccountLoaderCallback implements LoaderManager.LoaderCallbacks<
-            MailboxAccountLoader.Result> {
-        @Override
-        public Loader<MailboxAccountLoader.Result> onCreateLoader(int id, Bundle args) {
-            final long mailboxId = getMailboxId();
-            if (Logging.DEBUG_LIFECYCLE && Email.DEBUG) {
-                Log.d(Logging.LOG_TAG, MessageListFragment.this
-                        + " onCreateLoader(mailbox) mailboxId=" + mailboxId);
-            }
-            return new MailboxAccountLoader(getActivity().getApplicationContext(), mailboxId);
-        }
-
-        @Override
-        public void onLoadFinished(Loader<MailboxAccountLoader.Result> loader,
-                MailboxAccountLoader.Result result) {
-            if (Logging.DEBUG_LIFECYCLE && Email.DEBUG) {
-                Log.d(Logging.LOG_TAG, MessageListFragment.this
-                        + " onLoadFinished(mailbox) mailboxId=" + getMailboxId());
-            }
-            if (!result.mIsFound) {
-                mCallback.onMailboxNotFound();
-                return;
-            }
-
-            mAccount = result.mAccount;
-            mMailbox = result.mMailbox;
-            mIsEasAccount = result.mIsEasAccount;
-            mIsRefreshable = result.mIsRefreshable;
-            mCountTotalAccounts = result.mCountTotalAccounts;
-            getLoaderManager().initLoader(LOADER_ID_MESSAGES_LOADER, null,
-                    new MessagesLoaderCallback());
-        }
-
-        @Override
-        public void onLoaderReset(Loader<MailboxAccountLoader.Result> loader) {
-        }
     }
 
     /**
@@ -1211,11 +1168,25 @@ public class MessageListFragment extends ListFragment
         }
 
         @Override
-        public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
+        public void onLoadFinished(Loader<Cursor> loader, Cursor c) {
             if (Logging.DEBUG_LIFECYCLE && Email.DEBUG) {
                 Log.d(Logging.LOG_TAG, MessageListFragment.this
                         + " onLoadFinished(messages) mailboxId=" + getMailboxId());
             }
+            MessagesAdapter.CursorWithExtras cursor =
+                    (MessagesAdapter.CursorWithExtras) c;
+
+            if (!cursor.mIsFound) {
+                mCallback.onMailboxNotFound();
+                return;
+            }
+
+            // Get the "extras" part.
+            mAccount = cursor.mAccount;
+            mMailbox = cursor.mMailbox;
+            mIsEasAccount = cursor.mIsEasAccount;
+            mIsRefreshable = cursor.mIsRefreshable;
+            mCountTotalAccounts = cursor.mCountTotalAccounts;
 
             // Suspend message notifications as long as we're resumed
             adjustMessageNotification(false);

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

@@ -21,6 +21,7 @@ import com.android.email.ResourceHelper;
 import com.android.email.data.ThrottlingCursorLoader;
 import com.android.emailcommon.Logging;
 import com.android.emailcommon.provider.EmailContent;
+import com.android.emailcommon.provider.EmailContent.Account;
 import com.android.emailcommon.provider.EmailContent.Message;
 import com.android.emailcommon.provider.EmailContent.MessageColumns;
 import com.android.emailcommon.provider.Mailbox;
@@ -30,6 +31,7 @@ import com.android.emailcommon.utility.Utility;
 import android.content.Context;
 import android.content.Loader;
 import android.database.Cursor;
+import android.database.CursorWrapper;
 import android.database.MatrixCursor;
 import android.os.Bundle;
 import android.util.Log;
@@ -93,6 +95,36 @@ import java.util.Set;
 
     private final Callback mCallback;
 
+    /**
+     * The actual return type from the loader.
+     */
+    public static class CursorWithExtras extends CursorWrapper {
+        /**  Whether the mailbox is found. */
+        public final boolean mIsFound;
+        /** {@link Account} that owns the mailbox.  Null for combined mailboxes. */
+        public final Account mAccount;
+        /** {@link Mailbox} for the loaded mailbox. Null for combined mailboxes. */
+        public final Mailbox mMailbox;
+        /** {@code true} if the account is an EAS account */
+        public final boolean mIsEasAccount;
+        /** {@code true} if the loaded mailbox can be refreshed. */
+        public final boolean mIsRefreshable;
+        /** the number of accounts currently configured. */
+        public final int mCountTotalAccounts;
+
+        private CursorWithExtras(Cursor cursor,
+                boolean found, Account account, Mailbox mailbox, boolean isEasAccount,
+                boolean isRefreshable, int countTotalAccounts) {
+            super(cursor);
+            mIsFound = found;
+            mAccount = account;
+            mMailbox = mailbox;
+            mIsEasAccount = isEasAccount;
+            mIsRefreshable = isRefreshable;
+            mCountTotalAccounts = countTotalAccounts;
+        }
+    }
+
     public MessagesAdapter(Context context, Callback callback) {
         super(context.getApplicationContext(), null, 0 /* no auto requery */);
         mResourceHelper = ResourceHelper.getInstance(context);
@@ -222,6 +254,11 @@ import java.util.Set;
         view.invalidate();
     }
 
+    /**
+     * Creates the loader for {@link MessageListFragment}.
+     *
+     * @return always of {@link CursorWithExtras}.
+     */
     public static Loader<Cursor> createLoader(Context context, long mailboxId) {
         if (Logging.DEBUG_LIFECYCLE && Email.DEBUG) {
             Log.d(Logging.LOG_TAG, "MessagesAdapter createLoader mailboxId=" + mailboxId);
@@ -266,7 +303,35 @@ import java.util.Set;
                 // return an empty cursor
                 returnCursor = new MatrixCursor(getProjection());
             }
-            return Utility.CloseTraceCursorWrapper.get(returnCursor);
+            return loadExtras(returnCursor);
+        }
+
+        private Cursor loadExtras(Cursor baseCursor) {
+            boolean found = false;
+            Account account = null;
+            Mailbox mailbox = null;
+            boolean isEasAccount = false;
+            boolean isRefreshable = false;
+
+            if (mMailboxId < 0) {
+                // Magic mailbox.
+                found = true;
+            } else {
+                mailbox = Mailbox.restoreMailboxWithId(mContext, mMailboxId);
+                if (mailbox != null) {
+                    account = Account.restoreAccountWithId(mContext, mailbox.mAccountKey);
+                    if (account != null) {
+                        found = true;
+                        isEasAccount = account.isEasAccount(mContext) ;
+                        isRefreshable = Mailbox.isRefreshable(mContext, mMailboxId);
+                    } else { // Account removed?
+                        mailbox = null;
+                    }
+                }
+            }
+            final int countAccounts = EmailContent.count(mContext, Account.CONTENT_URI);
+            return new CursorWithExtras(baseCursor, found, account, mailbox, isEasAccount,
+                    isRefreshable, countAccounts);
         }
     }
 }

src/com/android/email/data/MailboxAccountLoader.java

@@ -1,107 +0,0 @@
-/*
- * 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.
- */
-
-package com.android.email.data;
-
-import com.android.emailcommon.provider.EmailContent;
-import com.android.emailcommon.provider.EmailContent.Account;
-import com.android.emailcommon.provider.Mailbox;
-
-import android.content.AsyncTaskLoader;
-import android.content.Context;
-
-
-/**
- * Loader to load {@link Mailbox} and {@link Account}.
- */
-public class MailboxAccountLoader extends AsyncTaskLoader<MailboxAccountLoader.Result> {
-    public static class Result {
-        public final boolean mIsFound;
-        public final Account mAccount;
-        public final Mailbox mMailbox;
-        public final boolean mIsEasAccount;
-        public final boolean mIsRefreshable;
-        public final int mCountTotalAccounts;
-
-        private Result(boolean found, Account account, Mailbox mailbox, boolean isEasAccount,
-                boolean isRefreshable, int countTotalAccounts) {
-            mIsFound = found;
-            mAccount = account;
-            mMailbox = mailbox;
-            mIsEasAccount = isEasAccount;
-            mIsRefreshable = isRefreshable;
-            mCountTotalAccounts = countTotalAccounts;
-        }
-    }
-
-    private final Context mContext;
-    private final long mMailboxId;
-
-    public MailboxAccountLoader(Context context, long mailboxId) {
-        super(context);
-        if (mailboxId == -1) {
-            throw new IllegalArgumentException();
-        }
-        mContext = context;
-        mMailboxId = mailboxId;
-    }
-
-    @Override
-    public Result loadInBackground() {
-        boolean found = false;
-        Account account = null;
-        Mailbox mailbox = null;
-        boolean isEasAccount = false;
-        boolean isRefreshable = false;
-
-        if (mMailboxId < 0) {
-            // Magic mailbox.
-            found = true;
-        } else {
-            mailbox = Mailbox.restoreMailboxWithId(mContext, mMailboxId);
-            if (mailbox != null) {
-                account = Account.restoreAccountWithId(mContext, mailbox.mAccountKey);
-                if (account != null) {
-                    found = true;
-                    isEasAccount = account.isEasAccount(mContext) ;
-                    isRefreshable = Mailbox.isRefreshable(mContext, mMailboxId);
-                } else { // Account removed?
-                    mailbox = null;
-                }
-            }
-        }
-        final int countAccounts = EmailContent.count(mContext, Account.CONTENT_URI);
-        Result result = new Result(found, account, mailbox, isEasAccount, isRefreshable,
-                countAccounts);
-        return result;
-    }
-
-    @Override
-    protected void onStartLoading() {
-        cancelLoad();
-        forceLoad();
-    }
-
-    @Override
-    protected void onStopLoading() {
-        cancelLoad();
-    }
-
-    @Override
-    protected void onReset() {
-        stopLoading();
-    }
-}

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

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.android.email.data;
+package com.android.email.activity;
 
 import com.android.email.DBTestHelper;
 import com.android.email.provider.ProviderTestUtils;
@@ -24,7 +24,13 @@ import com.android.emailcommon.provider.Mailbox;
 import android.content.Context;
 import android.test.LoaderTestCase;
 
-public class MailboxAccountLoaderTestCase extends LoaderTestCase {
+public class MessagesAdapterTests extends LoaderTestCase {
+    // Account ID that's probably not in the database.
+    private static final long NO_SUCH_ACCOUNT_ID = 1234567890123L;
+
+    // Mailbox ID that's probably not in the database.
+    private static final long NO_SUCH_MAILBOX_ID = 1234567890123L;
+
     // Isolated Context for providers.
     private Context mProviderContext;
 
@@ -50,6 +56,11 @@ public class MailboxAccountLoaderTestCase extends LoaderTestCase {
         return box.mId;
     }
 
+    private MessagesAdapter.CursorWithExtras getLoaderResult(long mailboxId) {
+        return (MessagesAdapter.CursorWithExtras) getLoaderResultSynchronously(
+                MessagesAdapter.createLoader(mProviderContext, mailboxId));
+    }
+
     /**
      * Test for normal case.  (account, mailbox found)
      */
@@ -57,8 +68,7 @@ public class MailboxAccountLoaderTestCase extends LoaderTestCase {
         final long accountId = createAccount(false);
         final long mailboxId = createMailbox(accountId, Mailbox.TYPE_MAIL);
 
-        MailboxAccountLoader.Result result = getLoaderResultSynchronously(
+        MessagesAdapter.CursorWithExtras result = getLoaderResult(mailboxId);
-                new MailboxAccountLoader(mProviderContext, mailboxId));
         assertTrue(result.mIsFound);
         assertEquals(accountId, result.mAccount.mId);
         assertEquals(mailboxId, result.mMailbox.mId);
@@ -73,8 +83,7 @@ public class MailboxAccountLoaderTestCase extends LoaderTestCase {
         final long accountId = createAccount(true);
         final long mailboxId = createMailbox(accountId, Mailbox.TYPE_MAIL);
 
-        MailboxAccountLoader.Result result = getLoaderResultSynchronously(
+        MessagesAdapter.CursorWithExtras result = getLoaderResult(mailboxId);
-                new MailboxAccountLoader(mProviderContext, mailboxId));
         assertTrue(result.mIsFound);
         assertEquals(accountId, result.mAccount.mId);
         assertEquals(mailboxId, result.mMailbox.mId);
@@ -89,8 +98,7 @@ public class MailboxAccountLoaderTestCase extends LoaderTestCase {
         final long accountId = createAccount(false);
         final long mailboxId = createMailbox(accountId, Mailbox.TYPE_DRAFTS);
 
-        MailboxAccountLoader.Result result = getLoaderResultSynchronously(
+        MessagesAdapter.CursorWithExtras result = getLoaderResult(mailboxId);
-                new MailboxAccountLoader(mProviderContext, mailboxId));
         assertTrue(result.mIsFound);
         assertEquals(accountId, result.mAccount.mId);
         assertEquals(mailboxId, result.mMailbox.mId);
@@ -102,8 +110,7 @@ public class MailboxAccountLoaderTestCase extends LoaderTestCase {
      * Mailbox not found.
      */
     public void testMailboxNotFound() {
-        MailboxAccountLoader.Result result = getLoaderResultSynchronously(
+        MessagesAdapter.CursorWithExtras result = getLoaderResult(NO_SUCH_MAILBOX_ID);
-                new MailboxAccountLoader(mProviderContext, 123));
         assertFalse(result.mIsFound);
         assertNull(result.mAccount);
         assertNull(result.mMailbox);
@@ -115,10 +122,9 @@ public class MailboxAccountLoaderTestCase extends LoaderTestCase {
      * Account not found.
      */
     public void testAccountNotFound() {
-        final long mailboxId = createMailbox(1, Mailbox.TYPE_MAIL);
+        final long mailboxId = createMailbox(NO_SUCH_ACCOUNT_ID, Mailbox.TYPE_MAIL);
 
-        MailboxAccountLoader.Result result = getLoaderResultSynchronously(
+        MessagesAdapter.CursorWithExtras result = getLoaderResult(mailboxId);
-                new MailboxAccountLoader(mProviderContext, mailboxId));
         assertFalse(result.mIsFound);
         assertNull(result.mAccount);
         assertNull(result.mMailbox);
@@ -130,8 +136,7 @@ public class MailboxAccountLoaderTestCase extends LoaderTestCase {
      * Magic mailbox.  (always found)
      */
     public void testMagicMailbox() {
-        MailboxAccountLoader.Result result = getLoaderResultSynchronously(
+        MessagesAdapter.CursorWithExtras result = getLoaderResult(Mailbox.QUERY_ALL_INBOXES);
-                new MailboxAccountLoader(mProviderContext, Mailbox.QUERY_ALL_INBOXES));
         assertTrue(result.mIsFound);
         assertNull(result.mAccount);
         assertNull(result.mMailbox);