Make BrowserSettings.loadFromDb asynchronous

loadFromDb does a lot of disk IO, including accessing SQLite
and SharedPreferences. This should not be done on the UI thread.
With this patch we move it into an AsyncTask. However there is one
caveat with this solution - all settings must be read and sent to
WebCore before BrowserActivity.onCreate is called so we must block
there if the async task is not complete. This is better than doing
the IO on the UI thread though and fixes a load of Browser StrictMode
violations.

Change-Id: I0ab37ee9e95c682a59d6170a1327ae4ad1deceec

3 files changed, 115 insertions, 73 deletions

diff --git a/src/com/android/browser/Browser.java b/src/com/android/browser/Browser.java
index 7822ec8..97b9967 100644
--- a/src/com/android/browser/Browser.java
+++ b/src/com/android/browser/Browser.java
@@ -57,7 +57,7 @@ public class Browser extends Application {
         CookieSyncManager.createInstance(this);
         // remove all expired cookies
         CookieManager.getInstance().removeExpiredCookie();
-        BrowserSettings.getInstance().loadFromDb(this);
+        BrowserSettings.getInstance().asyncLoadFromDb(this);
     }
 
     static Intent createBrowserViewIntent() {
diff --git a/src/com/android/browser/BrowserActivity.java b/src/com/android/browser/BrowserActivity.java
index 97da401..9844547 100644
--- a/src/com/android/browser/BrowserActivity.java
+++ b/src/com/android/browser/BrowserActivity.java
@@ -52,6 +52,11 @@ public class BrowserActivity extends Activity {
         }
         super.onCreate(icicle);
 
+        // We load the first set of BrowserSettings from the db asynchronously
+        // but if it has not completed at this point, we have no choice but
+        // to block waiting for them to finish loading. :(
+        BrowserSettings.getInstance().waitForLoadFromDbToComplete();
+
         // render the browser in OpenGL
         if (BrowserSettings.getInstance().isHardwareAccelerated()) {
             // Set the flag in the activity's window
diff --git a/src/com/android/browser/BrowserSettings.java b/src/com/android/browser/BrowserSettings.java
index 1229e4b..ba2f3fe 100644
--- a/src/com/android/browser/BrowserSettings.java
+++ b/src/com/android/browser/BrowserSettings.java
@@ -199,6 +199,18 @@ public class BrowserSettings extends Observable {
     private HashMap<WebSettings,Observer> mWebSettingsToObservers =
         new HashMap<WebSettings,Observer>();
 
+    private boolean mLoadFromDbComplete;
+
+    public void waitForLoadFromDbToComplete() {
+        synchronized (sSingleton) {
+            while (!mLoadFromDbComplete) {
+                try {
+                    sSingleton.wait();
+                } catch (InterruptedException e) { }
+            }
+        }
+    }
+
     /*
      * An observer wrapper for updating a WebSettings object with the new
      * settings after a call to BrowserSettings.update().
@@ -278,7 +290,8 @@ public class BrowserSettings extends Observable {
     }
 
     /**
-     * Load settings from the browser app's database.
+     * Load settings from the browser app's database. It is performed in
+     * an AsyncTask as it involves plenty of slow disk IO.
      * NOTE: Strings used for the preferences must match those specified
      * in the various preference XML files.
      * @param ctx A Context object used to query the browser's settings
@@ -286,81 +299,105 @@ public class BrowserSettings extends Observable {
      *            stored in this BrowserSettings object. This will update all
      *            observers of this object.
      */
-    public void loadFromDb(final Context ctx) {
-        SharedPreferences p =
-                PreferenceManager.getDefaultSharedPreferences(ctx);
-        // Set the default value for the Application Caches path.
-        appCachePath = ctx.getDir("appcache", 0).getPath();
-        // Determine the maximum size of the application cache.
-        webStorageSizeManager = new WebStorageSizeManager(
-                ctx,
-                new WebStorageSizeManager.StatFsDiskInfo(appCachePath),
-                new WebStorageSizeManager.WebKitAppCacheInfo(appCachePath));
-        appCacheMaxSize = webStorageSizeManager.getAppCacheMaxSize();
-        // Set the default value for the Database path.
-        databasePath = ctx.getDir("databases", 0).getPath();
-        // Set the default value for the Geolocation database path.
-        geolocationDatabasePath = ctx.getDir("geolocation", 0).getPath();
-
-        if (p.getString(PREF_HOMEPAGE, "") == "") {
-            // No home page preferences is set, set it to default.
-            setHomePage(ctx, getFactoryResetHomeUrl(ctx));
-        }
+    public void asyncLoadFromDb(final Context ctx) {
+        mLoadFromDbComplete = false;
+        // Run the initial settings load in an AsyncTask as it hits the
+        // disk multiple times through SharedPreferences and SQLite. We
+        // need to be certain though that this has completed before we start
+        // to load pages though, so in the worst case we will block waiting
+        // for it to finish in BrowserActivity.onCreate().
+         new LoadFromDbTask(ctx).execute();
+    }
 
-        // the cost of one cached page is ~3M (measured using nytimes.com). For
-        // low end devices, we only cache one page. For high end devices, we try
-        // to cache more pages, currently choose 5.
-        ActivityManager am = (ActivityManager) ctx
-                .getSystemService(Context.ACTIVITY_SERVICE);
-        if (am.getMemoryClass() > 16) {
-            pageCacheCapacity = 5;
-        } else {
-            pageCacheCapacity = 1;
-        }
+    private class LoadFromDbTask extends AsyncTask<Void, Void, Void> {
+        private Context mContext;
 
-        // Read the last active AutoFill profile id.
-        autoFillActiveProfileId = p.getInt(
-                PREF_AUTOFILL_ACTIVE_PROFILE_ID, autoFillActiveProfileId);
-
-        // Load the autofill profile data from the database. We use a database separate
-        // to the browser preference DB to make it easier to support multiple profiles
-        // and switching between them.
-        AutoFillProfileDatabase autoFillDb = AutoFillProfileDatabase.getInstance(ctx);
-        Cursor c = autoFillDb.getProfile(autoFillActiveProfileId);
-
-        if (c.getCount() > 0) {
-            c.moveToFirst();
-
-            String fullName = c.getString(c.getColumnIndex(
-                    AutoFillProfileDatabase.Profiles.FULL_NAME));
-            String email = c.getString(c.getColumnIndex(
-                    AutoFillProfileDatabase.Profiles.EMAIL_ADDRESS));
-            String company = c.getString(c.getColumnIndex(
-                    AutoFillProfileDatabase.Profiles.COMPANY_NAME));
-            String addressLine1 = c.getString(c.getColumnIndex(
-                    AutoFillProfileDatabase.Profiles.ADDRESS_LINE_1));
-            String addressLine2 = c.getString(c.getColumnIndex(
-                    AutoFillProfileDatabase.Profiles.ADDRESS_LINE_2));
-            String city = c.getString(c.getColumnIndex(
-                    AutoFillProfileDatabase.Profiles.CITY));
-            String state = c.getString(c.getColumnIndex(
-                    AutoFillProfileDatabase.Profiles.STATE));
-            String zip = c.getString(c.getColumnIndex(
-                    AutoFillProfileDatabase.Profiles.ZIP_CODE));
-            String country = c.getString(c.getColumnIndex(
-                    AutoFillProfileDatabase.Profiles.COUNTRY));
-            String phone = c.getString(c.getColumnIndex(
-                    AutoFillProfileDatabase.Profiles.PHONE_NUMBER));
-            autoFillProfile = new AutoFillProfile(autoFillActiveProfileId,
-                    fullName, email, company, addressLine1, addressLine2, city,
-                    state, zip, country, phone);
+        public LoadFromDbTask(Context context) {
+            mContext = context;
         }
-        c.close();
-        autoFillDb.close();
 
-        // PreferenceManager.setDefaultValues is TOO SLOW, need to manually keep
-        // the defaults in sync
-        syncSharedPreferences(ctx, p);
+        protected Void doInBackground(Void... unused) {
+            SharedPreferences p =
+                    PreferenceManager.getDefaultSharedPreferences(mContext);
+            // Set the default value for the Application Caches path.
+            appCachePath = mContext.getDir("appcache", 0).getPath();
+            // Determine the maximum size of the application cache.
+            webStorageSizeManager = new WebStorageSizeManager(
+                    mContext,
+                    new WebStorageSizeManager.StatFsDiskInfo(appCachePath),
+                    new WebStorageSizeManager.WebKitAppCacheInfo(appCachePath));
+            appCacheMaxSize = webStorageSizeManager.getAppCacheMaxSize();
+            // Set the default value for the Database path.
+            databasePath = mContext.getDir("databases", 0).getPath();
+            // Set the default value for the Geolocation database path.
+            geolocationDatabasePath = mContext.getDir("geolocation", 0).getPath();
+
+            if (p.getString(PREF_HOMEPAGE, "") == "") {
+                // No home page preferences is set, set it to default.
+                setHomePage(mContext, getFactoryResetHomeUrl(mContext));
+            }
+
+            // the cost of one cached page is ~3M (measured using nytimes.com). For
+            // low end devices, we only cache one page. For high end devices, we try
+            // to cache more pages, currently choose 5.
+            ActivityManager am = (ActivityManager) mContext
+                    .getSystemService(Context.ACTIVITY_SERVICE);
+            if (am.getMemoryClass() > 16) {
+                pageCacheCapacity = 5;
+            } else {
+                pageCacheCapacity = 1;
+            }
+
+            // Read the last active AutoFill profile id.
+            autoFillActiveProfileId = p.getInt(
+                    PREF_AUTOFILL_ACTIVE_PROFILE_ID, autoFillActiveProfileId);
+
+            // Load the autofill profile data from the database. We use a database separate
+            // to the browser preference DB to make it easier to support multiple profiles
+            // and switching between them.
+            AutoFillProfileDatabase autoFillDb = AutoFillProfileDatabase.getInstance(mContext);
+            Cursor c = autoFillDb.getProfile(autoFillActiveProfileId);
+
+            if (c.getCount() > 0) {
+                c.moveToFirst();
+
+                String fullName = c.getString(c.getColumnIndex(
+                        AutoFillProfileDatabase.Profiles.FULL_NAME));
+                String email = c.getString(c.getColumnIndex(
+                        AutoFillProfileDatabase.Profiles.EMAIL_ADDRESS));
+                String company = c.getString(c.getColumnIndex(
+                        AutoFillProfileDatabase.Profiles.COMPANY_NAME));
+                String addressLine1 = c.getString(c.getColumnIndex(
+                        AutoFillProfileDatabase.Profiles.ADDRESS_LINE_1));
+                String addressLine2 = c.getString(c.getColumnIndex(
+                        AutoFillProfileDatabase.Profiles.ADDRESS_LINE_2));
+                String city = c.getString(c.getColumnIndex(
+                        AutoFillProfileDatabase.Profiles.CITY));
+                String state = c.getString(c.getColumnIndex(
+                        AutoFillProfileDatabase.Profiles.STATE));
+                String zip = c.getString(c.getColumnIndex(
+                        AutoFillProfileDatabase.Profiles.ZIP_CODE));
+                String country = c.getString(c.getColumnIndex(
+                        AutoFillProfileDatabase.Profiles.COUNTRY));
+                String phone = c.getString(c.getColumnIndex(
+                        AutoFillProfileDatabase.Profiles.PHONE_NUMBER));
+                autoFillProfile = new AutoFillProfile(autoFillActiveProfileId,
+                        fullName, email, company, addressLine1, addressLine2, city,
+                        state, zip, country, phone);
+            }
+            c.close();
+            autoFillDb.close();
+
+            // PreferenceManager.setDefaultValues is TOO SLOW, need to manually keep
+            // the defaults in sync
+            syncSharedPreferences(mContext, p);
+
+            synchronized (sSingleton) {
+                mLoadFromDbComplete = true;
+                sSingleton.notify();
+            }
+            return null;
+        }
     }
 
     /* package */ void syncSharedPreferences(Context ctx, SharedPreferences p) {