Update issue 1623

Fixed severe design flaw where the message provider would accumulate messages, causing an OutOfMemoryError even when the message provider isn't explicitely invoked.
query() is now synchronized with message retrieval

src/com/fsck/k9/provider/MessageProvider.java

@@ -3,6 +3,8 @@ package com.fsck.k9.provider;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.SynchronousQueue;
 
 import android.app.Application;
 import android.content.ContentProvider;
@@ -32,6 +34,41 @@ import com.fsck.k9.mail.store.LocalStore;
 public class MessageProvider extends ContentProvider
 {
 
+    protected class MesssageInfoHolderRetrieverListener extends MessagingListener
+    {
+        private final BlockingQueue<List<MessageInfoHolder>> queue;
+
+        private List<MessageInfoHolder> holders = new ArrayList<MessageInfoHolder>();
+
+        private MesssageInfoHolderRetrieverListener(BlockingQueue<List<MessageInfoHolder>> queue)
+        {
+            this.queue = queue;
+        }
+
+        @Override
+        public void listLocalMessagesAddMessages(Account account,
+                String folder, List<Message> messages)
+        {
+            for (final Message message : messages)
+            {
+                holders.add(new MessageInfoHolder(context, message));
+            }
+        }
+
+        @Override
+        public void searchStats(AccountStats stats)
+        {
+            try
+            {
+                queue.put(holders);
+            }
+            catch (InterruptedException e)
+            {
+                Log.e(K9.LOG_TAG, "Unable to return message list back to caller", e);
+            }
+        }
+    }
+
     public static final String AUTHORITY = "com.fsck.k9.messageprovider";
 
     public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY);
@@ -45,17 +82,9 @@ public class MessageProvider extends ContentProvider
 
     private static Context context = null;
     private static boolean mIsListenerRegister = false;
-    private static boolean inSync = false;
 
     private static Application mApp;
 
-    /**
-     * list is synchronized, iterations have to be synchronized on the list
-     * instance in order to prevent concurrency issue
-     */
-    private final List<MessageInfoHolder> glb_messages = Collections.synchronizedList(new ArrayList<MessageInfoHolder>());
-    private static MatrixCursor mCursor;
-
     static
     {
         URI_MATCHER.addURI(AUTHORITY, "inbox_messages/", URI_INBOX_MESSAGES);
@@ -78,73 +107,10 @@ public class MessageProvider extends ContentProvider
     MessagingListener mListener = new MessagingListener()
     {
 
-        public void messageDeleted(Account account, String folder, Message message)
-        {
-        }
-
-        public void folderStatusChanged(Account account, String folderName, int unreadMessageCount)
-        {
-            if (inSync == false)
-            {
-                inSync = true;
-                glb_messages.clear();
-                SearchAccount integratedInboxAccount = new SearchAccount(getContext(), true, null,  null);
-                MessagingController msgController = MessagingController.getInstance(mApp);
-                msgController.searchLocalMessages(integratedInboxAccount, null, mListener);
-            }
-        }
-
-        public void listLocalMessagesStarted(Account account, String folder)
-        {
-        }
-
-        public void listLocalMessagesFinished(Account account, String folder)
-        {
-        }
-
         public void searchStats(AccountStats stats)
         {
-            int id = -1;
-            synchronized (glb_messages)
-            {
-                // TODO dynamically retrieve sort order instead of hardcoding
-                Collections.sort(glb_messages, new MessageList.ReverseComparator<MessageInfoHolder>(new MessageList.DateComparator()));
-            }
-            MatrixCursor tmpCur = new MatrixCursor(messages_projection);
-            synchronized (glb_messages)
-            {
-                for (MessageInfoHolder mi : glb_messages)
-                {
-                    ++id;
-                    Message msg = mi.message;
-                    tmpCur.addRow(new Object[]
-                    {
-                            id,
-                            mi.fullDate,
-                            mi.sender,
-                            mi.subject,
-                            mi.preview,
-                            mi.account,
-                            mi.uri,
-                            CONTENT_URI + "/delete_message/"
-                                    + msg.getFolder().getAccount().getAccountNumber() + "/"
-                                    + msg.getFolder().getName() + "/" + msg.getUid() });
-                }
-            }
-            mCursor = tmpCur;
-            inSync=false;
             notifyDatabaseModification();
         }
-
-        public void listLocalMessagesAddMessages(Account account, String folder, List<Message> messages)
-        {
-            for (Message m : messages)
-            {
-                MessageInfoHolder m1 = new MessageInfoHolder(context, m);
-                glb_messages.add(m1);
-            }
-        }
-
     };
 
     public Cursor getAllAccounts()
@@ -324,23 +290,54 @@ public class MessageProvider extends ContentProvider
         switch (URI_MATCHER.match(uri))
         {
             case URI_INBOX_MESSAGES:
+            {
+                final MatrixCursor mCursor = new MatrixCursor(messages_projection);
+                final BlockingQueue<List<MessageInfoHolder>> queue = new SynchronousQueue<List<MessageInfoHolder>>();
 
+                // new code for integrated inbox, only execute this once as it will be processed afterwards via the listener
+                SearchAccount integratedInboxAccount = new SearchAccount(getContext(), true, null,  null);
+                MessagingController msgController = MessagingController.getInstance(mApp);
 
-                if (mCursor == null)
+                msgController.searchLocalMessages(integratedInboxAccount, null,
+                        new MesssageInfoHolderRetrieverListener(queue));
+
+                List<MessageInfoHolder> holders;
+
+                try
                 {
-                    mCursor = new MatrixCursor(messages_projection);
-                    // new code for integrated inbox, only execute this once as it will be processed afterwards via the listener
-                    glb_messages.clear();
-                    SearchAccount integratedInboxAccount = new SearchAccount(getContext(), true, null,  null);
-                    MessagingController msgController = MessagingController.getInstance(mApp);
-                    msgController.searchLocalMessages(integratedInboxAccount, null, mListener);
+                    holders = queue.take();
+                }
+                catch (InterruptedException e)
+                {
+                    Log.e(K9.LOG_TAG, "Unable to retrieve message list", e);
+                    return null;
                 }
 
-// Process messages
+                Collections.sort(holders, new MessageList.ReverseComparator<MessageInfoHolder>(new MessageList.DateComparator()));
 
-//cursor = getAllMessages(projection, selection, selectionArgs, sortOrder);
-                cursor = (Cursor)mCursor;
+                int id = -1;
+                for (final MessageInfoHolder holder : holders)
+                {
+                    final Message message = holder.message;
+                    id++;
+
+                    mCursor.addRow(new Object[]
+                                              {
+                            id,
+                            holder.fullDate,
+                            holder.sender,
+                            holder.subject,
+                            holder.preview,
+                            holder.account,
+                            holder.uri,
+                            CONTENT_URI + "/delete_message/"
+                            + message.getFolder().getAccount().getAccountNumber() + "/"
+                            + message.getFolder().getName() + "/" + message.getUid() });
+                }
+
+                cursor = mCursor;
                 break;
+            }
 
             case URI_ACCOUNTS:
                 cursor = getAllAccounts();