Add activity that is displayed during database upgrades

See UpgradeDatabases.java for a detailed description of the upgrade
process.

AndroidManifest.xml

@@ -421,5 +421,13 @@ otherwise it would make K-9 start at the wrong time
         <activity
             android:name=".activity.AccountList">
         </activity>
+        <activity
+            android:name=".activity.UpgradeDatabases"
+            android:label="@string/upgrade_databases_title">
+        </activity>
+        <service
+            android:name=".service.DatabaseUpgradeService"
+            android:exported="false">
+        </service>
     </application>
 </manifest>

res/layout/upgrade_databases.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="fill_parent"
+    android:layout_height="fill_parent"
+    android:gravity="center_vertical|center_horizontal"
+    android:orientation="vertical" >
+
+    <ProgressBar
+        android:id="@+id/databaseUpgradeProgress"
+        style="?android:attr/progressBarStyleLarge"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content" />
+
+    <TextView
+        android:id="@+id/databaseUpgradeText"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="@string/upgrade_databases_unspecified" />
+
+</LinearLayout>

res/values/strings.xml

@@ -1093,4 +1093,8 @@ http://k9mail.googlecode.com/
 
     <string name="global_settings_threaded_view_label">Threaded view</string>
     <string name="global_settings_threaded_view_summary">Group messages by conversation</string>
+
+    <string name="upgrade_databases_title">Upgrading databases</string>
+    <string name="upgrade_databases_unspecified">Upgrading databases…</string>
+    <string name="upgrade_database_format">Upgrading database of account \"<xliff:g id="account">%s</xliff:g>\"</string>
 </resources>

src/com/fsck/k9/K9.java

@@ -15,6 +15,7 @@ import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.content.SharedPreferences;
+import android.content.SharedPreferences.Editor;
 import android.content.pm.PackageInfo;
 import android.content.pm.PackageManager;
 import android.content.pm.PackageManager.NameNotFoundException;
@@ -27,12 +28,14 @@ import android.util.Log;
 
 import com.fsck.k9.Account.SortType;
 import com.fsck.k9.activity.MessageCompose;
+import com.fsck.k9.activity.UpgradeDatabases;
 import com.fsck.k9.controller.MessagingController;
 import com.fsck.k9.controller.MessagingListener;
 import com.fsck.k9.mail.Address;
 import com.fsck.k9.mail.Message;
 import com.fsck.k9.mail.MessagingException;
 import com.fsck.k9.mail.internet.BinaryTempFileBody;
+import com.fsck.k9.mail.store.LocalStore;
 import com.fsck.k9.provider.UnreadWidgetProvider;
 import com.fsck.k9.service.BootReceiver;
 import com.fsck.k9.service.MailService;
@@ -64,6 +67,23 @@ public class K9 extends Application {
     public static File tempDirectory;
     public static final String LOG_TAG = "k9";
 
+    /**
+     * Name of the {@link SharedPreferences} file used to store the last known version of the
+     * accounts' databases.
+     *
+     * <p>
+     * See {@link UpgradeDatabases} for a detailed explanation of the database upgrade process.
+     * </p>
+     */
+    private static final String DATABASE_VERSION_CACHE = "database_version_cache";
+
+    /**
+     * Key used to store the last known database version of the accounts' databases.
+     *
+     * @see #DATABASE_VERSION_CACHE
+     */
+    private static final String KEY_LAST_ACCOUNT_DATABASE_VERSION = "last_account_database_version";
+
     /**
      * Components that are interested in knowing when the K9 instance is
      * available and ready.
@@ -150,6 +170,16 @@ public class K9 extends Application {
     public static boolean ENABLE_ERROR_FOLDER = true;
     public static String ERROR_FOLDER_NAME = "K9mail-errors";
 
+    /**
+     * A reference to the {@link SharedPreferences} used for caching the last known database
+     * version.
+     *
+     * @see #checkCachedDatabaseVersion()
+     * @see #setDatabasesUpToDate(boolean)
+     */
+    private static SharedPreferences sDatabaseVersionCache;
+
+
     private static boolean mAnimations = true;
 
     private static boolean mConfirmDelete = false;
@@ -208,6 +238,11 @@ public class K9 extends Application {
     private static boolean sUseBackgroundAsUnreadIndicator = true;
     private static boolean sThreadedViewEnabled = true;
 
+    /**
+     * @see #areDatabasesUpToDate()
+     */
+    private static boolean sDatabasesUpToDate = false;
+
 
     /**
      * The MIME type(s) of attachments we're willing to view.
@@ -487,6 +522,8 @@ public class K9 extends Application {
 
         galleryBuggy = checkForBuggyGallery();
 
+        checkCachedDatabaseVersion();
+
         Preferences prefs = Preferences.getPreferences(this);
         loadPrefs(prefs);
 
@@ -581,6 +618,31 @@ public class K9 extends Application {
         notifyObservers();
     }
 
+    /**
+     * Loads the last known database version of the accounts' databases from a
+     * {@link SharedPreference}.
+     *
+     * <p>
+     * If the stored version matches {@link LocalStore#DB_VERSION} we know that the databases are
+     * up to date.<br>
+     * Using {@code SharedPreferences} should be a lot faster than opening all SQLite databases to
+     * get the current database version.
+     * </p><p>
+     * See {@link UpgradeDatabases} for a detailed explanation of the database upgrade process.
+     * </p>
+     *
+     * @see #areDatabasesUpToDate()
+     */
+    public void checkCachedDatabaseVersion() {
+        sDatabaseVersionCache = getSharedPreferences(DATABASE_VERSION_CACHE, MODE_PRIVATE);
+
+        int cachedVersion = sDatabaseVersionCache.getInt(KEY_LAST_ACCOUNT_DATABASE_VERSION, 0);
+
+        if (cachedVersion < LocalStore.DB_VERSION) {
+            K9.setDatabasesUpToDate(false);
+        }
+    }
+
     public static void loadPrefs(Preferences prefs) {
         SharedPreferences sprefs = prefs.getPreferences();
         DEBUG = sprefs.getBoolean("enableDebugLogging", false);
@@ -1150,4 +1212,38 @@ public class K9 extends Application {
     public static synchronized void setThreadedViewEnabled(boolean enable) {
         sThreadedViewEnabled = enable;
     }
+
+    /**
+     * Check if we already know whether all databases are using the current database schema.
+     *
+     * <p>
+     * This method is only used for optimizations. If it returns {@code true} we can be certain that
+     * getting a {@link LocalStore} instance won't trigger a schema upgrade.
+     * </p>
+     *
+     * @return {@code true}, if we know that all databases are using the current database schema.
+     *         {@code false}, otherwise.
+     */
+    public static synchronized boolean areDatabasesUpToDate() {
+        return sDatabasesUpToDate;
+    }
+
+    /**
+     * Remember that all account databases are using the most recent database schema.
+     *
+     * @param save
+     *         Whether or not to write the current database version to the
+     *         {@code SharedPreferences} {@link #DATABASE_VERSION_CACHE}.
+     *
+     * @see #areDatabasesUpToDate()
+     */
+    public static synchronized void setDatabasesUpToDate(boolean save) {
+        sDatabasesUpToDate = true;
+
+        if (save) {
+            Editor editor = sDatabaseVersionCache.edit();
+            editor.putInt(KEY_LAST_ACCOUNT_DATABASE_VERSION, LocalStore.DB_VERSION);
+            editor.commit();
+        }
+    }
 }

src/com/fsck/k9/activity/Accounts.java

@@ -371,6 +371,12 @@ public class Accounts extends K9ListActivity implements OnItemClickListener {
         if (accounts.length < 1) {
             WelcomeMessage.showWelcomeMessage(this);
             finish();
+            return;
+        }
+
+        if (UpgradeDatabases.actionUpgradeDatabases(this, intent)) {
+            finish();
+            return;
         }
 
         boolean startup = intent.getBooleanExtra(EXTRA_STARTUP, true);

src/com/fsck/k9/activity/UpgradeDatabases.java

@@ -0,0 +1,220 @@
+package com.fsck.k9.activity;
+
+import com.fsck.k9.Account;
+import com.fsck.k9.K9;
+import com.fsck.k9.Preferences;
+import com.fsck.k9.R;
+import com.fsck.k9.mail.Store;
+import com.fsck.k9.service.DatabaseUpgradeService;
+
+import android.app.Activity;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.content.SharedPreferences;
+import android.os.Bundle;
+import android.support.v4.content.LocalBroadcastManager;
+import android.widget.TextView;
+
+
+/**
+ * This activity triggers a database upgrade if necessary and displays the current upgrade progress.
+ *
+ * <p>
+ * The current upgrade process works as follows:
+ * <ol>
+ * <li>Activities that access an account's database call
+ *     {@link #actionUpgradeDatabases(Context, Intent)} in their {@link Activity#onCreate(Bundle)}
+ *     method.</li>
+ * <li>{@link #actionUpgradeDatabases(Context, Intent)} will call {@link K9#areDatabasesUpToDate()}
+ *     to check if we already know whether the databases have been upgraded.</li>
+ * <li>{@link K9#areDatabasesUpToDate()} will compare the last known database version stored in a
+ *     {@link SharedPreferences} file to {@link com.fsck.k9.mail.store.LocalStore#DB_VERSION}. This
+ *     is done as an optimization because it's faster than opening all of the accounts' databases
+ *     one by one.</li>
+ * <li>If there was an error reading the cached database version or if it shows the databases need
+ *     upgrading this activity ({@code UpgradeDatabases}) is started.</li>
+ * <li>This activity will display a spinning progress indicator and start
+ *     {@link DatabaseUpgradeService}.</li>
+ * <li>{@link DatabaseUpgradeService} will acquire a partial wake lock (with a 10 minute timeout),
+ *     start a background thread to perform the database upgrades, and report the progress using
+ *     {@link LocalBroadcastManager} to this activity which will update the UI accordingly.</li>
+ * <li>Once the upgrade is complete {@link DatabaseUpgradeService} will notify this activity,
+ *     release the wake lock, and stop itself.</li>
+ * <li>This activity will start the original activity using the intent supplied when calling
+ *     {@link #actionUpgradeDatabases(Context, Intent)}.</li>
+ * </ol>
+ * </p><p>
+ * Currently we make no attempts to stop the background code (e.g. {@link MessagingController}) from
+ * opening the accounts' databases. If this happens the upgrade is performed in one of the
+ * background threads and not by {@link DatabaseUpgradeService}. But this is not a problem. Due to
+ * the locking in {@link Store#getLocalInstance(Account, android.app.Application)} the upgrade
+ * service will block in the {@link Account#getLocalStore()} call and from the outside (especially
+ * for this activity) it will appear as if {@link DatabaseUpgradeService} is performing the upgrade.
+ * </p>
+ */
+public class UpgradeDatabases extends K9Activity {
+    private static final String ACTION_UPGRADE_DATABASES = "upgrade_databases";
+    private static final String EXTRA_START_INTENT = "start_intent";
+
+
+    /**
+     * Start the {@link UpgradeDatabases} activity if necessary.
+     *
+     * @param context
+     *         The {@link Context} used to start the activity.
+     * @param startIntent
+     *         After the database upgrade is complete an activity is started using this intent.
+     *         Usually this is the intent that was used to start the calling activity.
+     *         Never {@code null}.
+     *
+     * @return {@code true}, if the {@code UpgradeDatabases} activity was started. In this case the
+     *         calling activity is expected to finish itself.<br>
+     *         {@code false}, if the account databases don't need upgrading.
+     */
+    public static boolean actionUpgradeDatabases(Context context, Intent startIntent) {
+        if (K9.areDatabasesUpToDate()) {
+            return false;
+        }
+
+        Intent intent = new Intent(context, UpgradeDatabases.class);
+        intent.setAction(ACTION_UPGRADE_DATABASES);
+        intent.putExtra(EXTRA_START_INTENT, startIntent);
+
+        // Make sure this activity is only running once
+        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_SINGLE_TOP);
+
+        context.startActivity(intent);
+        return true;
+    }
+
+
+    private Intent mStartIntent;
+
+    private TextView mUpgradeText;
+
+    private LocalBroadcastManager mLocalBroadcastManager;
+    private UpgradeDatabaseBroadcastReceiver mBroadcastReceiver;
+    private IntentFilter mIntentFilter;
+    private Preferences mPreferences;
+
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        // If the databases have already been upgraded there's no point in displaying this activity.
+        if (K9.areDatabasesUpToDate()) {
+            launchOriginalActivity();
+            return;
+        }
+
+        mPreferences = Preferences.getPreferences(getApplicationContext());
+
+        initializeLayout();
+
+        decodeExtras();
+
+        setupBroadcastReceiver();
+    }
+
+    /**
+     * Initialize the activity's layout
+     */
+    private void initializeLayout() {
+        setContentView(R.layout.upgrade_databases);
+
+        mUpgradeText = (TextView) findViewById(R.id.databaseUpgradeText);
+    }
+
+    /**
+     * Decode extras in the intent used to start this activity.
+     */
+    private void decodeExtras() {
+        Intent intent = getIntent();
+        mStartIntent = intent.getParcelableExtra(EXTRA_START_INTENT);
+    }
+
+    /**
+     * Setup the broadcast receiver used to receive progress updates from
+     * {@link DatabaseUpgradeService}.
+     */
+    private void setupBroadcastReceiver() {
+        mLocalBroadcastManager = LocalBroadcastManager.getInstance(this);
+        mBroadcastReceiver = new UpgradeDatabaseBroadcastReceiver();
+
+        mIntentFilter = new IntentFilter(DatabaseUpgradeService.ACTION_UPGRADE_PROGRESS);
+        mIntentFilter.addAction(DatabaseUpgradeService.ACTION_UPGRADE_COMPLETE);
+    }
+
+    @Override
+    public void onResume() {
+        super.onResume();
+
+        // Check if the upgrade was completed while the activity was paused.
+        if (K9.areDatabasesUpToDate()) {
+            launchOriginalActivity();
+            return;
+        }
+
+        // Register the broadcast receiver to listen for progress reports from
+        // DatabaseUpgradeService.
+        mLocalBroadcastManager.registerReceiver(mBroadcastReceiver, mIntentFilter);
+
+        // Now that the broadcast receiver was registered start DatabaseUpgradeService.
+        DatabaseUpgradeService.startService(this);
+    }
+
+    @Override
+    public void onPause() {
+        // The activity is being paused, so there's no point in listening to the progress of the
+        // database upgrade service.
+        mLocalBroadcastManager.unregisterReceiver(mBroadcastReceiver);
+
+        super.onPause();
+    }
+
+    /**
+     * Finish this activity and launch the original activity using the supplied intent.
+     */
+    private void launchOriginalActivity() {
+        finish();
+        startActivity(mStartIntent);
+    }
+
+    /**
+     * Receiver for broadcasts send by {@link DatabaseUpgradeService}.
+     */
+    class UpgradeDatabaseBroadcastReceiver extends BroadcastReceiver {
+
+        @Override
+        public void onReceive(Context context, final Intent intent) {
+            String action = intent.getAction();
+
+            if (DatabaseUpgradeService.ACTION_UPGRADE_PROGRESS.equals(action)) {
+                /*
+                 * Information on the current upgrade progress
+                 */
+
+                String accountUuid = intent.getStringExtra(
+                        DatabaseUpgradeService.EXTRA_ACCOUNT_UUID);
+
+                Account account = mPreferences.getAccount(accountUuid);
+
+                if (account != null) {
+                    String formatString = getString(R.string.upgrade_database_format);
+                    String upgradeStatus = String.format(formatString, account.getDescription());
+                    mUpgradeText.setText(upgradeStatus);
+                }
+
+            } else if (DatabaseUpgradeService.ACTION_UPGRADE_COMPLETE.equals(action)) {
+                /*
+                 * Upgrade complete
+                 */
+
+                launchOriginalActivity();
+            }
+        }
+    }
+}

src/com/fsck/k9/mail/Store.java

@@ -3,6 +3,7 @@ package com.fsck.k9.mail;
 
 import java.util.HashMap;
 import java.util.List;
+import java.util.concurrent.ConcurrentHashMap;
 
 import android.app.Application;
 import android.content.Context;
@@ -33,10 +34,16 @@ public abstract class Store {
     private static HashMap<String, Store> sStores = new HashMap<String, Store>();
 
     /**
-     * Local stores indexed by UUid because the Uri may change due to migration to/from SD-card.
+     * Local stores indexed by UUID because the Uri may change due to migration to/from SD-card.
      */
-    private static HashMap<String, Store> sLocalStores = new HashMap<String, Store>();
+    private static ConcurrentHashMap<String, Store> sLocalStores = new ConcurrentHashMap<String, Store>();
 
+    /**
+     * Lock objects indexed by account UUID.
+     *
+     * @see #getLocalInstance(Account, Application)
+     */
+    private static ConcurrentHashMap<String, Object> sAccountLocks = new ConcurrentHashMap<String, Object>();
 
     /**
      * Get an instance of a remote mail store.
@@ -72,16 +79,36 @@ public abstract class Store {
 
     /**
      * Get an instance of a local mail store.
-     * @throws UnavailableStorageException if not {@link StorageProvider#isReady(Context)}
+     *
+     * @throws UnavailableStorageException
+     *          if not {@link StorageProvider#isReady(Context)}
      */
-    public synchronized static LocalStore getLocalInstance(Account account, Application application) throws MessagingException {
-        Store store = sLocalStores.get(account.getUuid());
-        if (store == null) {
-            store = new LocalStore(account, application);
-            sLocalStores.put(account.getUuid(), store);
-        }
+    public static LocalStore getLocalInstance(Account account, Application application)
+            throws MessagingException {
 
-        return (LocalStore) store;
+        String accountUuid = account.getUuid();
+
+        // Create new per-account lock object if necessary
+        sAccountLocks.putIfAbsent(accountUuid, new Object());
+
+        // Get the account's lock object
+        Object lock = sAccountLocks.get(accountUuid);
+
+        // Use per-account locks so DatabaseUpgradeService always knows which account database is
+        // currently upgraded.
+        synchronized (lock) {
+            Store store = sLocalStores.get(accountUuid);
+
+            if (store == null) {
+                // Creating a LocalStore instance will create or upgrade the database if
+                // necessary. This could take some time.
+                store = new LocalStore(account, application);
+
+                sLocalStores.put(accountUuid, store);
+            }
+
+            return (LocalStore) store;
+        }
     }
 
     /**

src/com/fsck/k9/mail/store/LocalStore.java

@@ -111,7 +111,7 @@ public class LocalStore extends Store implements Serializable {
      */
     private static final int UID_CHECK_BATCH_SIZE = 500;
 
-    protected static final int DB_VERSION = 45;
+    public static final int DB_VERSION = 45;
 
     protected String uUid = null;