Issue 143

Merged from branch issue143 @ revision 426:

Complete replacement for SharedPreferences.  Uses SQLite database
stored in application's databases folder.

Will load from legacy preferences if DB-backed preferences are empty.

Editor conforms to atomic commit contract.

src/com/android/email/Account.java

@@ -101,35 +101,35 @@ public class Account implements Serializable {
      * Refresh the account from the stored settings.
      */
     public void refresh(Preferences preferences) {
-        mStoreUri = Utility.base64Decode(preferences.mSharedPreferences.getString(mUuid
+        mStoreUri = Utility.base64Decode(preferences.getPreferences().getString(mUuid
                 + ".storeUri", null));
-        mLocalStoreUri = preferences.mSharedPreferences.getString(mUuid + ".localStoreUri", null);
+        mLocalStoreUri = preferences.getPreferences().getString(mUuid + ".localStoreUri", null);
-        mTransportUri = Utility.base64Decode(preferences.mSharedPreferences.getString(mUuid
+        mTransportUri = Utility.base64Decode(preferences.getPreferences().getString(mUuid
                 + ".transportUri", null));
-        mDescription = preferences.mSharedPreferences.getString(mUuid + ".description", null);
+        mDescription = preferences.getPreferences().getString(mUuid + ".description", null);
-        mAlwaysBcc = preferences.mSharedPreferences.getString(mUuid + ".alwaysBcc", mAlwaysBcc);
+        mAlwaysBcc = preferences.getPreferences().getString(mUuid + ".alwaysBcc", mAlwaysBcc);
-        mName = preferences.mSharedPreferences.getString(mUuid + ".name", mName);
+        mName = preferences.getPreferences().getString(mUuid + ".name", mName);
-        mEmail = preferences.mSharedPreferences.getString(mUuid + ".email", mEmail);
+        mEmail = preferences.getPreferences().getString(mUuid + ".email", mEmail);
-        mSignature = preferences.mSharedPreferences.getString(mUuid + ".signature", mSignature);
+        mSignature = preferences.getPreferences().getString(mUuid + ".signature", mSignature);
-        mAutomaticCheckIntervalMinutes = preferences.mSharedPreferences.getInt(mUuid
+        mAutomaticCheckIntervalMinutes = preferences.getPreferences().getInt(mUuid
                 + ".automaticCheckIntervalMinutes", -1);
-        mDisplayCount = preferences.mSharedPreferences.getInt(mUuid + ".displayCount", -1);
+        mDisplayCount = preferences.getPreferences().getInt(mUuid + ".displayCount", -1);
-        mLastAutomaticCheckTime = preferences.mSharedPreferences.getLong(mUuid
+        mLastAutomaticCheckTime = preferences.getPreferences().getLong(mUuid
                 + ".lastAutomaticCheckTime", 0);
-        mNotifyNewMail = preferences.mSharedPreferences.getBoolean(mUuid + ".notifyNewMail", 
+        mNotifyNewMail = preferences.getPreferences().getBoolean(mUuid + ".notifyNewMail", 
                 false);
-        mNotifySync = preferences.mSharedPreferences.getBoolean(mUuid + ".notifyMailCheck", 
+        mNotifySync = preferences.getPreferences().getBoolean(mUuid + ".notifyMailCheck", 
 																   false);
-        mDeletePolicy = preferences.mSharedPreferences.getInt(mUuid + ".deletePolicy", 0);
+        mDeletePolicy = preferences.getPreferences().getInt(mUuid + ".deletePolicy", 0);
-        mDraftsFolderName = preferences.mSharedPreferences.getString(mUuid  + ".draftsFolderName", 
+        mDraftsFolderName = preferences.getPreferences().getString(mUuid  + ".draftsFolderName", 
                 "Drafts");
-        mSentFolderName = preferences.mSharedPreferences.getString(mUuid  + ".sentFolderName", 
+        mSentFolderName = preferences.getPreferences().getString(mUuid  + ".sentFolderName", 
                 "Sent");
-        mTrashFolderName = preferences.mSharedPreferences.getString(mUuid  + ".trashFolderName", 
+        mTrashFolderName = preferences.getPreferences().getString(mUuid  + ".trashFolderName", 
                 "Trash");
-        mOutboxFolderName = preferences.mSharedPreferences.getString(mUuid  + ".outboxFolderName", 
+        mOutboxFolderName = preferences.getPreferences().getString(mUuid  + ".outboxFolderName", 
                 "Outbox");
-        
+
         // Between r418 and r431 (version 0.103), folder names were set empty if the Incoming settings were
         // opened for non-IMAP accounts.  0.103 was never a market release, so perhaps this code
         // should be deleted sometime soon
@@ -151,14 +151,15 @@ public class Account implements Serializable {
         }
         // End of 0.103 repair
         
-        mAutoExpandFolderName = preferences.mSharedPreferences.getString(mUuid  + ".autoExpandFolderName", 
+        mAutoExpandFolderName = preferences.getPreferences().getString(mUuid  + ".autoExpandFolderName", 
           "Inbox");
-        mAccountNumber = preferences.mSharedPreferences.getInt(mUuid + ".accountNumber", 0);
+        
-        mVibrate = preferences.mSharedPreferences.getBoolean(mUuid + ".vibrate", false);
+        mAccountNumber = preferences.getPreferences().getInt(mUuid + ".accountNumber", 0);
+        mVibrate = preferences.getPreferences().getBoolean(mUuid + ".vibrate", false);
 
         try
         {
-          mHideMessageViewButtons = HideButtons.valueOf(preferences.mSharedPreferences.getString(mUuid + ".hideButtonsEnum", 
+          mHideMessageViewButtons = HideButtons.valueOf(preferences.getPreferences().getString(mUuid + ".hideButtonsEnum", 
               HideButtons.NEVER.name()));
         }
         catch (Exception e)
@@ -166,11 +167,11 @@ public class Account implements Serializable {
           mHideMessageViewButtons = HideButtons.NEVER;
         }
 
-        mRingtoneUri = preferences.mSharedPreferences.getString(mUuid  + ".ringtone", 
+        mRingtoneUri = preferences.getPreferences().getString(mUuid  + ".ringtone", 
                 "content://settings/system/notification_sound");
         try
         {
-        	mFolderDisplayMode = FolderMode.valueOf(preferences.mSharedPreferences.getString(mUuid  + ".folderDisplayMode", 
+        	mFolderDisplayMode = FolderMode.valueOf(preferences.getPreferences().getString(mUuid  + ".folderDisplayMode", 
         			FolderMode.NOT_SECOND_CLASS.name()));
         }
         catch (Exception e)
@@ -180,7 +181,7 @@ public class Account implements Serializable {
 
         try
         {
-        	mFolderSyncMode = FolderMode.valueOf(preferences.mSharedPreferences.getString(mUuid  + ".folderSyncMode", 
+        	mFolderSyncMode = FolderMode.valueOf(preferences.getPreferences().getString(mUuid  + ".folderSyncMode", 
         			FolderMode.FIRST_CLASS.name()));
         }
         catch (Exception e)
@@ -190,7 +191,7 @@ public class Account implements Serializable {
         
         try
         {
-          mFolderTargetMode = FolderMode.valueOf(preferences.mSharedPreferences.getString(mUuid  + ".folderTargetMode", 
+          mFolderTargetMode = FolderMode.valueOf(preferences.getPreferences().getString(mUuid  + ".folderTargetMode", 
               FolderMode.NOT_SECOND_CLASS.name()));
         }
         catch (Exception e)
@@ -278,7 +279,7 @@ public class Account implements Serializable {
     }
 
     public void delete(Preferences preferences) {
-        String[] uuids = preferences.mSharedPreferences.getString("accountUuids", "").split(",");
+        String[] uuids = preferences.getPreferences().getString("accountUuids", "").split(",");
         StringBuffer sb = new StringBuffer();
         for (int i = 0, length = uuids.length; i < length; i++) {
             if (!uuids[i].equals(mUuid)) {
@@ -289,7 +290,7 @@ public class Account implements Serializable {
             }
         }
         String accountUuids = sb.toString();
-        SharedPreferences.Editor editor = preferences.mSharedPreferences.edit();
+        SharedPreferences.Editor editor = preferences.getPreferences().edit();
         editor.putString("accountUuids", accountUuids);
 
         editor.remove(mUuid + ".storeUri");
@@ -320,9 +321,9 @@ public class Account implements Serializable {
     }
 
     public void save(Preferences preferences) {
-      SharedPreferences.Editor editor = preferences.mSharedPreferences.edit();
+      SharedPreferences.Editor editor = preferences.getPreferences().edit();
 
-        if (!preferences.mSharedPreferences.getString("accountUuids", "").contains(mUuid)) {
+        if (!preferences.getPreferences().getString("accountUuids", "").contains(mUuid)) {
             /*
              * When the account is first created we assign it a unique account number. The
              * account number will be unique to that account for the lifetime of the account.
@@ -348,15 +349,11 @@ public class Account implements Serializable {
             }
             mAccountNumber++;
             
-            String accountUuids = preferences.mSharedPreferences.getString("accountUuids", "");
+            String accountUuids = preferences.getPreferences().getString("accountUuids", "");
             accountUuids += (accountUuids.length() != 0 ? "," : "") + mUuid;
-  //          SharedPreferences.Editor editor = preferences.mSharedPreferences.edit();
             editor.putString("accountUuids", accountUuids);
-  //          editor.commit();
         }
 
- //       SharedPreferences.Editor editor = preferences.mSharedPreferences.edit();
-
         editor.putString(mUuid + ".storeUri", Utility.base64Encode(mStoreUri));
         editor.putString(mUuid + ".localStoreUri", mLocalStoreUri);
         editor.putString(mUuid + ".transportUri", Utility.base64Encode(mTransportUri));

src/com/android/email/Preferences.java

@@ -3,6 +3,9 @@ package com.android.email;
 
 import java.util.Arrays;
 
+import com.android.email.preferences.Editor;
+import com.android.email.preferences.Storage;
+
 import android.content.Context;
 import android.content.SharedPreferences;
 import android.net.Uri;
@@ -12,11 +15,19 @@ import android.util.Log;
 public class Preferences {
     private static Preferences preferences;
 
-    public SharedPreferences mSharedPreferences;
+    private Storage mStorage;
 
     private Preferences(Context context) {
-        mSharedPreferences = context.getSharedPreferences("AndroidMail.Main", Context.MODE_PRIVATE);
+      mStorage = Storage.getStorage(context);
+      if (mStorage.size() == 0)
+      {
+        Log.i(Email.LOG_TAG, "Preferences storage is zero-size, importing from Android-style preferences");
+        Editor editor = mStorage.edit();
+        editor.copy(context.getSharedPreferences("AndroidMail.Main", Context.MODE_PRIVATE));
+        editor.commit();
+      }
     }
+    
 
     /**
      * TODO need to think about what happens if this gets GCed along with the
@@ -40,7 +51,7 @@ public class Preferences {
      * @return
      */
     public Account[] getAccounts() {
-        String accountUuids = mSharedPreferences.getString("accountUuids", null);
+        String accountUuids = getPreferences().getString("accountUuids", null);
         if (accountUuids == null || accountUuids.length() == 0) {
             return new Account[] {};
         }
@@ -64,7 +75,7 @@ public class Preferences {
      * @return
      */
     public Account getDefaultAccount() {
-        String defaultAccountUuid = mSharedPreferences.getString("defaultAccountUuid", null);
+        String defaultAccountUuid = getPreferences().getString("defaultAccountUuid", null);
         Account defaultAccount = null;
         Account[] accounts = getAccounts();
         if (defaultAccountUuid != null) {
@@ -87,37 +98,35 @@ public class Preferences {
     }
 
     public void setDefaultAccount(Account account) {
-        mSharedPreferences.edit().putString("defaultAccountUuid", account.getUuid()).commit();
+        getPreferences().edit().putString("defaultAccountUuid", account.getUuid()).commit();
     }
 
     public void setEnableDebugLogging(boolean value) {
-        mSharedPreferences.edit().putBoolean("enableDebugLogging", value).commit();
+        getPreferences().edit().putBoolean("enableDebugLogging", value).commit();
     }
 
     public boolean geteEnableDebugLogging() {
-        return mSharedPreferences.getBoolean("enableDebugLogging", false);
+        return getPreferences().getBoolean("enableDebugLogging", false);
     }
 
     public void setEnableSensitiveLogging(boolean value) {
-        mSharedPreferences.edit().putBoolean("enableSensitiveLogging", value).commit();
+        getPreferences().edit().putBoolean("enableSensitiveLogging", value).commit();
     }
 
     public boolean getEnableSensitiveLogging() {
-        return mSharedPreferences.getBoolean("enableSensitiveLogging", false);
+        return getPreferences().getBoolean("enableSensitiveLogging", false);
-    }
-
-    public void save() {
-    }
-
-    public void clear() {
-        mSharedPreferences.edit().clear().commit();
     }
 
     public void dump() {
         if (Config.LOGV) {
-            for (String key : mSharedPreferences.getAll().keySet()) {
+            for (String key : getPreferences().getAll().keySet()) {
-                Log.v(Email.LOG_TAG, key + " = " + mSharedPreferences.getAll().get(key));
+                Log.v(Email.LOG_TAG, key + " = " + getPreferences().getAll().get(key));
             }
         }
     }
+
+    public SharedPreferences getPreferences()
+    {
+      return mStorage;
+    }
 }

src/com/android/email/mail/store/LocalStore.java

@@ -701,7 +701,7 @@ public class LocalStore extends Store implements Serializable {
         public void delete(Preferences preferences) throws MessagingException {
         	String id = getPrefId();
           
-        	SharedPreferences.Editor editor = preferences.mSharedPreferences.edit();
+        	SharedPreferences.Editor editor = preferences.getPreferences().edit();
           
         	editor.remove(id + ".displayMode");
           editor.remove(id + ".syncMode");
@@ -712,7 +712,7 @@ public class LocalStore extends Store implements Serializable {
       public void save(Preferences preferences) throws MessagingException {
       		String id = getPrefId();
         
-          SharedPreferences.Editor editor = preferences.mSharedPreferences.edit();
+          SharedPreferences.Editor editor = preferences.getPreferences().edit();
           // there can be a lot of folders.  For the defaults, let's not save prefs, saving space, except for INBOX
           if (displayClass == FolderClass.NONE && !Email.INBOX.equals(getName()))
           {
@@ -740,7 +740,7 @@ public class LocalStore extends Store implements Serializable {
       		
         try
         {
-        	displayClass = FolderClass.valueOf(preferences.mSharedPreferences.getString(id + ".displayMode", 
+        	displayClass = FolderClass.valueOf(preferences.getPreferences().getString(id + ".displayMode", 
         			FolderClass.NONE.name()));
         }
         catch (Exception e)
@@ -759,7 +759,7 @@ public class LocalStore extends Store implements Serializable {
         
         try
         {
-        	syncClass = FolderClass.valueOf(preferences.mSharedPreferences.getString(id  + ".syncMode", 
+        	syncClass = FolderClass.valueOf(preferences.getPreferences().getString(id  + ".syncMode", 
         			defSyncClass.name()));
         }
         catch (Exception e)

src/com/android/email/preferences/Editor.java

@@ -0,0 +1,161 @@
+package com.android.email.preferences;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Map.Entry;
+
+import com.android.email.Email;
+
+import android.util.Log;
+
+public class Editor implements android.content.SharedPreferences.Editor
+{
+  private Storage storage;
+  private HashMap<String, String> changes = new HashMap<String, String>();
+  private ArrayList<String> removals = new ArrayList<String>();
+  private boolean removeAll = false;
+  
+  Map<String, String> snapshot = new HashMap<String, String>();
+  
+  
+  protected Editor(Storage storage)
+  {
+    this.storage = storage;
+    snapshot.putAll(storage.getAll());
+  }
+  
+  public void copy(android.content.SharedPreferences input)
+  {
+    Map<String, ?> oldVals = input.getAll();
+    for (Entry<String, ?> entry : oldVals.entrySet())
+    {
+      String key = entry.getKey();
+      Object value = entry.getValue();
+      if (key != null && value != null)
+      {
+        if (Email.DEBUG)
+        {
+          Log.d(Email.LOG_TAG, "Copying key '" + key + "', value '" + value + "'");
+        }
+        changes.put(key, "" + value);
+      }
+      else
+      {
+        if (Email.DEBUG)
+        {
+          Log.d(Email.LOG_TAG, "Skipping copying key '" + key + "', value '" + value + "'");
+        }
+      }
+    }
+  }
+  
+  @Override
+  public android.content.SharedPreferences.Editor clear()
+  {
+    removeAll = true;
+    return this;
+  }
+
+  /* This method is poorly defined.  It should throw an Exception on failure */
+  @Override
+  public boolean commit()
+  {
+    try
+    {
+      commitChanges();
+      return true;
+    }
+    catch (Exception e)
+    {
+      Log.e(Email.LOG_TAG, "Failed to save preferences", e);
+      return false;
+    }
+  }
+  
+  public void commitChanges() throws Exception
+  {
+    long startTime = System.currentTimeMillis();
+    Log.i(Email.LOG_TAG, "Committing preference changes");
+    Runnable committer = new Runnable() {
+      public void run()
+      {
+        if (removeAll)
+        {
+          storage.removeAll();
+        }
+        for (String removeKey : removals)
+        {
+          storage.remove(removeKey);
+        }
+        for (Entry<String, String> entry : changes.entrySet())
+        {
+          String key = entry.getKey();
+          String newValue = entry.getValue();
+          String oldValue = snapshot.get(key);
+          if (removeAll || removals.contains(key) || newValue.equals(oldValue) != true)
+          {
+            storage.put(key, newValue);
+          }
+        }
+      }
+    };
+    storage.doInTransaction(committer);
+    long endTime = System.currentTimeMillis();
+    Log.i(Email.LOG_TAG, "Preferences commit took " + (endTime - startTime) + "ms");
+    
+  }
+
+  @Override
+  public android.content.SharedPreferences.Editor putBoolean(String key,
+      boolean value)
+  {
+    changes.put(key, "" + value);
+    return this;
+  }
+
+  @Override
+  public android.content.SharedPreferences.Editor putFloat(String key,
+      float value)
+  {
+    changes.put(key, "" + value);
+    return this;
+  }
+
+  @Override
+  public android.content.SharedPreferences.Editor putInt(String key, int value)
+  {
+    changes.put(key, "" + value);
+    return this;
+  }
+
+  @Override
+  public android.content.SharedPreferences.Editor putLong(String key, long value)
+  {
+    changes.put(key, "" + value);
+    return this;
+  }
+
+  @Override
+  public android.content.SharedPreferences.Editor putString(String key,
+      String value)
+  {
+    if (value == null)
+    {
+      remove(key);
+    }
+    else
+    {
+      changes.put(key, value);
+    }
+    return this;
+  }
+
+  @Override
+  public android.content.SharedPreferences.Editor remove(String key)
+  {
+    removals.add(key);
+    return this;
+  }
+
+}

src/com/android/email/preferences/Storage.java

@@ -0,0 +1,291 @@
+package com.android.email.preferences;
+
+import java.util.ArrayList;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CopyOnWriteArrayList;
+
+import com.android.email.Email;
+
+import android.content.ContentValues;
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteDatabase;
+import android.util.Log;
+
+public class Storage implements SharedPreferences
+{
+  private static ConcurrentHashMap<Context, Storage> storages =
+    new ConcurrentHashMap<Context, Storage>();
+  
+  private volatile ConcurrentHashMap<String, String> storage = new ConcurrentHashMap<String, String>();
+  
+  private CopyOnWriteArrayList<OnSharedPreferenceChangeListener> listeners = 
+    new CopyOnWriteArrayList<OnSharedPreferenceChangeListener>();
+  
+  private int DB_VERSION = 1;  // CHANGING THIS WILL DESTROY ALL USER PREFERENCES!
+  private String DB_NAME = "preferences_storage";
+  
+  private ThreadLocal<ConcurrentHashMap<String, String>> workingStorage 
+    = new ThreadLocal<ConcurrentHashMap<String, String>>();
+  private ThreadLocal<SQLiteDatabase> workingDB =
+    new ThreadLocal<SQLiteDatabase>();
+  private ThreadLocal<ArrayList<String>> workingChangedKeys = new ThreadLocal<ArrayList<String>>();
+  
+  
+  private Context context = null;
+  
+  private SQLiteDatabase openDB()
+  {
+    SQLiteDatabase mDb = context.openOrCreateDatabase(DB_NAME, Context.MODE_PRIVATE, null);
+    if (mDb.getVersion() != DB_VERSION) 
+    {
+      Log.i(Email.LOG_TAG, "Creating Storage database");
+      mDb.execSQL("DROP TABLE IF EXISTS preferences_storage");
+      mDb.execSQL("CREATE TABLE preferences_storage " +
+              "(primkey TEXT PRIMARY KEY ON CONFLICT REPLACE, value TEXT)");
+      mDb.setVersion(DB_VERSION);
+    }
+    return mDb;
+  }
+  
+  
+  public static Storage getStorage(Context context)
+  {
+    Storage tmpStorage = storages.get(context);
+    if (tmpStorage != null)
+    { 
+      if (Email.DEBUG)
+      {
+        Log.d(Email.LOG_TAG, "Returning already existing Storage");
+      }
+      return tmpStorage;
+    }
+    else
+    {
+      if (Email.DEBUG)
+      {
+        Log.d(Email.LOG_TAG, "Creating provisional storage");
+      }
+      tmpStorage = new Storage(context);
+      Storage oldStorage = storages.putIfAbsent(context, tmpStorage);
+      if (oldStorage != null)
+      {
+        if (Email.DEBUG)
+        {
+          Log.d(Email.LOG_TAG, "Another thread beat us to creating the Storage, returning that one");
+        }
+        return oldStorage;
+      }
+      else
+      {
+        if (Email.DEBUG)
+        {
+          Log.d(Email.LOG_TAG, "Returning the Storage we created");
+        }
+        return tmpStorage;
+      }
+    }
+  }
+  
+  private void loadValues()
+  {
+    long startTime = System.currentTimeMillis();
+    Log.i(Email.LOG_TAG, "Loading preferences from DB into Storage");
+    Cursor cursor = null;
+    try {
+      SQLiteDatabase mDb = openDB();
+
+      cursor = mDb.rawQuery("SELECT primkey, value FROM preferences_storage", null);
+      while (cursor.moveToNext()) {
+        String key = cursor.getString(0);
+        String value = cursor.getString(1);
+        if (Email.DEBUG)
+        {
+          Log.d(Email.LOG_TAG, "Loading key '" + key + "', value = '" + value + "'");
+        }
+        storage.put(key, value);
+      }
+    }
+    finally {
+      if (cursor != null) {
+        cursor.close();
+      }
+      long endTime = System.currentTimeMillis();
+      Log.i(Email.LOG_TAG, "Preferences load took " + (endTime - startTime) + "ms");
+    }
+  }
+  
+  private Storage(Context context)
+  {
+    this.context = context;
+    loadValues();
+  }
+  
+  private void keyChange(String key)
+  {
+    ArrayList<String> changedKeys = workingChangedKeys.get();
+    if (changedKeys.contains(key) == false)
+    {
+      changedKeys.add(key);
+    }
+  }
+
+  protected void put(String key, String value)
+  {
+    ContentValues cv = new ContentValues();
+    cv.put("primkey", key);
+    cv.put("value", value);
+    workingDB.get().insert("preferences_storage", "primkey", cv);
+    workingStorage.get().put(key, value);
+    
+    keyChange(key);
+  }
+  
+  protected void remove(String key)
+  { 
+    workingDB.get().delete("preferences_storage", "primkey = ?", new String[] { key }); 
+    workingStorage.get().remove(key);
+
+    keyChange(key);
+  }
+  
+  protected void removeAll()
+  {
+    for (String key : workingStorage.get().keySet())
+    {
+      keyChange(key);
+    }
+    workingDB.get().execSQL("DELETE FROM preferences_storage");
+    workingStorage.get().clear();
+  }
+  
+  protected void doInTransaction(Runnable dbWork)
+  {
+    ConcurrentHashMap<String, String> newStorage = new ConcurrentHashMap<String, String>();
+    newStorage.putAll(storage);
+    workingStorage.set(newStorage);
+   
+    SQLiteDatabase mDb = openDB();
+    workingDB.set(mDb);
+    
+    ArrayList<String> changedKeys = new ArrayList<String>();
+    workingChangedKeys.set(changedKeys);
+
+    mDb.beginTransaction();
+    try
+    {
+      dbWork.run();
+      mDb.setTransactionSuccessful();
+      storage = newStorage;
+      for (String changedKey : changedKeys)
+      {
+        for (OnSharedPreferenceChangeListener listener : listeners)
+        {
+          listener.onSharedPreferenceChanged(this, changedKey);
+        }
+      }
+    }
+    finally
+    {
+      workingDB.remove();
+      workingStorage.remove();
+      workingChangedKeys.remove();
+      mDb.endTransaction();
+    }
+  }
+  
+  public long size()
+  {
+    return storage.size();
+  }
+  
+  @Override
+  public boolean contains(String key)
+  {
+    return storage.contains(key);
+  }
+
+  @Override
+  public com.android.email.preferences.Editor edit()
+  {
+    return new com.android.email.preferences.Editor(this);
+  }
+
+  @Override
+  public Map<String, String> getAll()
+  {
+    return storage;
+  }
+
+  @Override
+  public boolean getBoolean(String key, boolean defValue)
+  {
+    String val = storage.get(key);
+    if (val == null)
+    {
+      return defValue;
+    }
+    return Boolean.parseBoolean(val);
+  }
+
+  @Override
+  public float getFloat(String key, float defValue)
+  {
+    String val = storage.get(key);
+    if (val == null)
+    {
+      return defValue;
+    }
+    return Float.parseFloat(val);
+  }
+
+  @Override
+  public int getInt(String key, int defValue)
+  {
+    String val = storage.get(key);
+    if (val == null)
+    {
+      return defValue;
+    }
+    return Integer.parseInt(val);
+  }
+
+  @Override
+  public long getLong(String key, long defValue)
+  {
+    String val = storage.get(key);
+    if (val == null)
+    {
+      return defValue;
+    }
+    return Long.parseLong(val);
+  }
+
+  @Override
+  public String getString(String key, String defValue)
+  {
+    String val = storage.get(key);
+    if (val == null)
+    {
+      return defValue;
+    }
+    return val;
+  }
+
+  @Override
+  public void registerOnSharedPreferenceChangeListener(
+      OnSharedPreferenceChangeListener listener)
+  {
+    listeners.addIfAbsent(listener);    
+  }
+
+  @Override
+  public void unregisterOnSharedPreferenceChangeListener(
+      OnSharedPreferenceChangeListener listener)
+  {
+    listeners.remove(listener);
+  }
+
+}