resolved conflicts for merge of ee78e780 to master

Change-Id: I88a4996bdd17c5378a67781d8075eff311670c3b

java/src/com/android/inputmethod/latin/UserHistoryDictionary.java

@@ -32,6 +32,7 @@ import com.android.inputmethod.latin.UserHistoryForgettingCurveUtils.ForgettingC
 import java.lang.ref.SoftReference;
 import java.util.HashMap;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.locks.ReentrantLock;
 
 /**
  * Locally gathers stats about the words user types and various other signals like auto-correction
@@ -40,6 +41,8 @@ import java.util.concurrent.ConcurrentHashMap;
 public class UserHistoryDictionary extends ExpandableDictionary {
     private static final String TAG = "UserHistoryDictionary";
     public static final boolean DBG_SAVE_RESTORE = false;
+    public static final boolean DBG_STRESS_TEST = false;
+    public static final boolean DBG_ALWAYS_WRITE = false;
     public static final boolean PROFILE_SAVE_RESTORE = LatinImeLogger.sDBG;
 
     /** Any pair being typed or picked */
@@ -82,7 +85,7 @@ public class UserHistoryDictionary extends ExpandableDictionary {
 
     private final UserHistoryDictionaryBigramList mBigramList =
             new UserHistoryDictionaryBigramList();
-    private static volatile boolean sUpdatingDB = false;
+    private final ReentrantLock mBigramListLock = new ReentrantLock();
     private final SharedPreferences mPrefs;
 
     private final static HashMap<String, String> sDictProjectionMap;
@@ -173,7 +176,10 @@ public class UserHistoryDictionary extends ExpandableDictionary {
      * The second word may not be null (a NullPointerException would be thrown).
      */
     public int addToUserHistory(final String word1, String word2, boolean isValid) {
-        super.addWord(word2, null /* the "shortcut" parameter is null */, FREQUENCY_FOR_TYPED);
+        if (mBigramListLock.tryLock()) {
+            try {
+                super.addWord(
+                        word2, null /* the "shortcut" parameter is null */, FREQUENCY_FOR_TYPED);
                 // Do not insert a word as a bigram of itself
                 if (word2.equals(word1)) {
                     return 0;
@@ -182,20 +188,27 @@ public class UserHistoryDictionary extends ExpandableDictionary {
                 if (null == word1) {
                     freq = FREQUENCY_FOR_TYPED;
                 } else {
-            freq = super.setBigramAndGetFrequency(word1, word2, new ForgettingCurveParams(isValid));
+                    freq = super.setBigramAndGetFrequency(
+                            word1, word2, new ForgettingCurveParams(isValid));
                 }
-        synchronized (mBigramList) {
                 mBigramList.addBigram(word1, word2);
-        }
-
                 return freq;
+            } finally {
+                mBigramListLock.unlock();
+            }
+        }
+        return -1;
     }
 
     public boolean cancelAddingUserHistory(String word1, String word2) {
-        synchronized (mBigramList) {
+        if (mBigramListLock.tryLock()) {
+            try {
                 if (mBigramList.removeBigram(word1, word2)) {
                     return super.removeBigram(word1, word2);
                 }
+            } finally {
+                mBigramListLock.unlock();
+            }
         }
         return false;
     }
@@ -204,30 +217,33 @@ public class UserHistoryDictionary extends ExpandableDictionary {
      * Schedules a background thread to write any pending words to the database.
      */
     private void flushPendingWrites() {
-        synchronized (mBigramList) {
+        if (mBigramListLock.isLocked()) {
-            // Nothing pending? Return
-            if (mBigramList.isEmpty()) return;
-            // Create a background thread to write the pending entries
-            new UpdateDbTask(sOpenHelper, mBigramList, mLocale, this, mPrefs).execute();
-        }
-    }
-
-    /** Used for testing purpose **/
-    void waitUntilUpdateDBDone() {
-        synchronized (mBigramList) {
-            while (sUpdatingDB) {
-                try {
-                    Thread.sleep(100);
-                } catch (InterruptedException e) {
-                }
-            }
             return;
         }
+        // Create a background thread to write the pending entries
+        new UpdateDbTask(sOpenHelper, mBigramList, mLocale, this, mPrefs).execute();
     }
 
     @Override
     public void loadDictionaryAsync() {
-        synchronized(mBigramList) {
+        // This must be run on non-main thread
+        mBigramListLock.lock();
+        try {
+            loadDictionaryAsyncLocked();
+        } finally {
+            mBigramListLock.unlock();
+        }
+    }
+
+    private void loadDictionaryAsyncLocked() {
+        if (DBG_STRESS_TEST) {
+            try {
+                Log.w(TAG, "Start stress in loading: " + mLocale);
+                Thread.sleep(15000);
+                Log.w(TAG, "End stress in loading");
+            } catch (InterruptedException e) {
+            }
+        }
         final long last = SettingsValues.getLastUserHistoryWriteTime(mPrefs, mLocale);
         final boolean initializing = last == 0;
         final long now = System.currentTimeMillis();
@@ -235,6 +251,7 @@ public class UserHistoryDictionary extends ExpandableDictionary {
         final Cursor cursor = query(MAIN_COLUMN_LOCALE + "=?", new String[] { mLocale });
         if (null == cursor) return;
         try {
+            // TODO: Call SQLiteDataBase.beginTransaction / SQLiteDataBase.endTransaction
             if (cursor.moveToFirst()) {
                 final int word1Index = cursor.getColumnIndex(MAIN_COLUMN_WORD1);
                 final int word2Index = cursor.getColumnIndex(MAIN_COLUMN_WORD2);
@@ -270,7 +287,6 @@ public class UserHistoryDictionary extends ExpandableDictionary {
             }
         }
     }
-    }
 
     /**
      * Query the database
@@ -387,19 +403,11 @@ public class UserHistoryDictionary extends ExpandableDictionary {
             }
         }
 
-        @Override
-        protected void onPreExecute() {
-            sUpdatingDB = true;
-        }
-
         @Override
         protected Void doInBackground(Void... v) {
-            synchronized(mBigramList) {
-                final long now = PROFILE_SAVE_RESTORE ? System.currentTimeMillis() : 0;
-                int profTotal = 0;
-                int profInsert = 0;
-                int profDelete = 0;
             SQLiteDatabase db = null;
+            if (mUserHistoryDictionary.mBigramListLock.tryLock()) {
+                try {
                     try {
                         db = mDbHelper.getWritableDatabase();
                     } catch (android.database.sqlite.SQLiteCantOpenDatabaseException e) {
@@ -408,9 +416,33 @@ public class UserHistoryDictionary extends ExpandableDictionary {
                     }
                     if (null == db) {
                         // Not much we can do. Just exit.
-                    sUpdatingDB = false;
                         return null;
                     }
+                    db.beginTransaction();
+                    return doLoadTaskLocked(db);
+                } finally {
+                    if (db != null) {
+                        db.endTransaction();
+                    }
+                    mUserHistoryDictionary.mBigramListLock.unlock();
+                }
+            }
+            return null;
+        }
+
+        private Void doLoadTaskLocked(SQLiteDatabase db) {
+            if (DBG_STRESS_TEST) {
+                try {
+                    Log.w(TAG, "Start stress in closing: " + mLocale);
+                    Thread.sleep(15000);
+                    Log.w(TAG, "End stress in closing");
+                } catch (InterruptedException e) {
+                }
+            }
+            final long now = PROFILE_SAVE_RESTORE ? System.currentTimeMillis() : 0;
+            int profTotal = 0;
+            int profInsert = 0;
+            int profDelete = 0;
             db.execSQL("PRAGMA foreign_keys = ON;");
             final boolean addLevel0Bigram = mBigramList.size() <= sMaxHistoryBigrams;
 
@@ -433,14 +465,16 @@ public class UserHistoryDictionary extends ExpandableDictionary {
                                 Log.d(TAG, "Skip update user history: " + word1 + "," + word2
                                         + "," + prevFc);
                             }
+                            if (!DBG_ALWAYS_WRITE) {
                                 continue;
                             }
+                        }
                     } else { // bigram
                         final NextWord nw = mUserHistoryDictionary.getBigramWord(word1, word2);
                         if (nw != null) {
                             final ForgettingCurveParams fcp = nw.getFcParams();
                             final byte prevFc = word1Bigrams.get(word2);
-                                final byte fc = fcp.getFc();
+                            final byte fc = (byte)fcp.getFc();
                             final boolean isValid = fcp.isValid();
                             if (prevFc > 0 && prevFc == fc) {
                                 // No need to update since we found no changes for this entry.
@@ -449,7 +483,11 @@ public class UserHistoryDictionary extends ExpandableDictionary {
                                     Log.d(TAG, "Skip update user history: " + word1 + ","
                                             + word2 + "," + prevFc);
                                 }
+                                if (!DBG_ALWAYS_WRITE) {
                                     continue;
+                                } else {
+                                    freq = fc;
+                                }
                             } else if (UserHistoryForgettingCurveUtils.
                                     needsToSave(fc, isValid, addLevel0Bigram)) {
                                 freq = fc;
@@ -519,15 +557,14 @@ public class UserHistoryDictionary extends ExpandableDictionary {
             checkPruneData(db);
             // Save the timestamp after we finish writing the SQL DB.
             SettingsValues.setLastUserHistoryWriteTime(mPrefs, mLocale);
-                sUpdatingDB = false;
             if (PROFILE_SAVE_RESTORE) {
                 final long diff = System.currentTimeMillis() - now;
                 Log.w(TAG, "PROF: Write User HistoryDictionary: " + mLocale + ", "+ diff
                         + "ms. Total: " + profTotal + ". Insert: " + profInsert + ". Delete: "
                         + profDelete);
             }
+            db.setTransactionSuccessful();
             return null;
-            } // synchronized
         }
 
         private static ContentValues getContentValues(String word1, String word2, String locale) {