Refactor on UserHistoryDictionary

Bug: 9429906
Change-Id: I576a91643bdaf5017cc826ac2e07a74a9a275d60

1 files changed, 421 insertions, 0 deletions

diff --git a/java/src/com/android/inputmethod/latin/personalization/UserHistoryDictionary.java b/java/src/com/android/inputmethod/latin/personalization/UserHistoryDictionary.java
new file mode 100644
index 000000000..a5d6f0497
--- /dev/null
+++ b/java/src/com/android/inputmethod/latin/personalization/UserHistoryDictionary.java
@@ -0,0 +1,421 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.inputmethod.latin.personalization;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.os.AsyncTask;
+import android.util.Log;
+
+import com.android.inputmethod.annotations.UsedForTesting;
+import com.android.inputmethod.keyboard.ProximityInfo;
+import com.android.inputmethod.latin.Constants;
+import com.android.inputmethod.latin.Dictionary;
+import com.android.inputmethod.latin.ExpandableDictionary;
+import com.android.inputmethod.latin.LatinImeLogger;
+import com.android.inputmethod.latin.WordComposer;
+import com.android.inputmethod.latin.SuggestedWords.SuggestedWordInfo;
+import com.android.inputmethod.latin.makedict.FormatSpec.FormatOptions;
+import com.android.inputmethod.latin.settings.Settings;
+import com.android.inputmethod.latin.utils.ByteArrayWrapper;
+import com.android.inputmethod.latin.utils.CollectionUtils;
+import com.android.inputmethod.latin.utils.UserHistoryDictIOUtils;
+import com.android.inputmethod.latin.utils.UserHistoryDictIOUtils.BigramDictionaryInterface;
+import com.android.inputmethod.latin.utils.UserHistoryDictIOUtils.OnAddWordListener;
+import com.android.inputmethod.latin.utils.UserHistoryForgettingCurveUtils;
+import com.android.inputmethod.latin.utils.UserHistoryForgettingCurveUtils.ForgettingCurveParams;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.lang.ref.SoftReference;
+import java.util.ArrayList;
+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
+ * cancellation or manual picks. This allows the keyboard to adapt to the typist over time.
+ */
+public final class UserHistoryDictionary extends ExpandableDictionary {
+    private static final String TAG = UserHistoryDictionary.class.getSimpleName();
+    private static final String NAME = UserHistoryDictionary.class.getSimpleName();
+    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;
+
+    private static final FormatOptions VERSION3 = new FormatOptions(3,
+            true /* supportsDynamicUpdate */);
+
+    /** Any pair being typed or picked */
+    private static final int FREQUENCY_FOR_TYPED = 2;
+
+    /** Maximum number of pairs. Pruning will start when databases goes above this number. */
+    public static final int MAX_HISTORY_BIGRAMS = 10000;
+
+    /**
+     * When it hits maximum bigram pair, it will delete until you are left with
+     * only (sMaxHistoryBigrams - sDeleteHistoryBigrams) pairs.
+     * Do not keep this number small to avoid deleting too often.
+     */
+    public static final int DELETE_HISTORY_BIGRAMS = 1000;
+
+    /** Locale for which this user history dictionary is storing words */
+    private final String mLocale;
+
+    private final UserHistoryDictionaryBigramList mBigramList =
+            new UserHistoryDictionaryBigramList();
+    private final ReentrantLock mBigramListLock = new ReentrantLock();
+    private final SharedPreferences mPrefs;
+
+    // Should always be false except when we use this class for test
+    @UsedForTesting boolean isTest = false;
+
+    private static final ConcurrentHashMap<String, SoftReference<UserHistoryDictionary>>
+            sLangDictCache = CollectionUtils.newConcurrentHashMap();
+
+    public static synchronized UserHistoryDictionary getInstance(
+            final Context context, final String locale, final SharedPreferences sp) {
+        if (sLangDictCache.containsKey(locale)) {
+            final SoftReference<UserHistoryDictionary> ref = sLangDictCache.get(locale);
+            final UserHistoryDictionary dict = ref == null ? null : ref.get();
+            if (dict != null) {
+                if (PROFILE_SAVE_RESTORE) {
+                    Log.w(TAG, "Use cached UserHistoryDictionary for " + locale);
+                }
+                return dict;
+            }
+        }
+        final UserHistoryDictionary dict =
+                new UserHistoryDictionary(context, locale, sp);
+        sLangDictCache.put(locale, new SoftReference<UserHistoryDictionary>(dict));
+        return dict;
+    }
+
+    private UserHistoryDictionary(final Context context, final String locale,
+            final SharedPreferences sp) {
+        super(context, Dictionary.TYPE_USER_HISTORY);
+        mLocale = locale;
+        mPrefs = sp;
+        if (mLocale != null && mLocale.length() > 1) {
+            loadDictionary();
+        }
+    }
+
+    @Override
+    public void close() {
+        flushPendingWrites();
+        // Don't close the database as locale changes will require it to be reopened anyway
+        // Also, the database is written to somewhat frequently, so it needs to be kept alive
+        // throughout the life of the process.
+        // mOpenHelper.close();
+        // Ignore close because we cache UserHistoryDictionary for each language. See getInstance()
+        // above.
+        // super.close();
+    }
+
+    @Override
+    protected ArrayList<SuggestedWordInfo> getWordsInner(final WordComposer composer,
+            final String prevWord, final ProximityInfo proximityInfo) {
+        // Inhibit suggestions (not predictions) for user history for now. Removing this method
+        // is enough to use it through the standard ExpandableDictionary way.
+        return null;
+    }
+
+    /**
+     * Return whether the passed charsequence is in the dictionary.
+     */
+    @Override
+    public synchronized boolean isValidWord(final String word) {
+        // TODO: figure out what is the correct thing to do here.
+        return false;
+    }
+
+    /**
+     * Pair will be added to the user history dictionary.
+     *
+     * The first word may be null. That means we don't know the context, in other words,
+     * it's only a unigram. The first word may also be an empty string : this means start
+     * context, as in beginning of a sentence for example.
+     * The second word may not be null (a NullPointerException would be thrown).
+     */
+    public int addToUserHistory(final String word1, final String word2, final boolean isValid) {
+        if (word2.length() >= Constants.DICTIONARY_MAX_WORD_LENGTH ||
+                (word1 != null && word1.length() >= Constants.DICTIONARY_MAX_WORD_LENGTH)) {
+            return -1;
+        }
+        if (mBigramListLock.tryLock()) {
+            try {
+                super.addWord(
+                        word2, null /* the "shortcut" parameter is null */, FREQUENCY_FOR_TYPED);
+                mBigramList.addBigram(null, word2, (byte)FREQUENCY_FOR_TYPED);
+                // Do not insert a word as a bigram of itself
+                if (word2.equals(word1)) {
+                    return 0;
+                }
+                final int freq;
+                if (null == word1) {
+                    freq = FREQUENCY_FOR_TYPED;
+                } else {
+                    freq = super.setBigramAndGetFrequency(
+                            word1, word2, new ForgettingCurveParams(isValid));
+                }
+                mBigramList.addBigram(word1, word2);
+                return freq;
+            } finally {
+                mBigramListLock.unlock();
+            }
+        }
+        return -1;
+    }
+
+    public boolean cancelAddingUserHistory(final String word1, final String word2) {
+        if (mBigramListLock.tryLock()) {
+            try {
+                if (mBigramList.removeBigram(word1, word2)) {
+                    return super.removeBigram(word1, word2);
+                }
+            } finally {
+                mBigramListLock.unlock();
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Schedules a background thread to write any pending words to the database.
+     */
+    private void flushPendingWrites() {
+        // Create a background thread to write the pending entries
+        new UpdateBinaryTask(mBigramList, mLocale, this, mPrefs, getContext()).execute();
+    }
+
+    @Override
+    public void loadDictionaryAsync() {
+        // This must be run on non-main thread
+        mBigramListLock.lock();
+        try {
+            loadDictionaryAsyncLocked();
+        } finally {
+            mBigramListLock.unlock();
+        }
+    }
+
+    private int profTotal;
+
+    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 = Settings.readLastUserHistoryWriteTime(mPrefs, mLocale);
+        final boolean initializing = last == 0;
+        final long now = System.currentTimeMillis();
+        profTotal = 0;
+        final String fileName = NAME + "." + mLocale + ".dict";
+        final ExpandableDictionary dictionary = this;
+        final OnAddWordListener listener = new OnAddWordListener() {
+            @Override
+            public void setUnigram(final String word, final String shortcutTarget,
+                    final int frequency) {
+                profTotal++;
+                if (DBG_SAVE_RESTORE) {
+                    Log.d(TAG, "load unigram: " + word + "," + frequency);
+                }
+                dictionary.addWord(word, shortcutTarget, frequency);
+                mBigramList.addBigram(null, word, (byte)frequency);
+            }
+
+            @Override
+            public void setBigram(final String word1, final String word2, final int frequency) {
+                if (word1.length() < Constants.DICTIONARY_MAX_WORD_LENGTH
+                        && word2.length() < Constants.DICTIONARY_MAX_WORD_LENGTH) {
+                    profTotal++;
+                    if (DBG_SAVE_RESTORE) {
+                        Log.d(TAG, "load bigram: " + word1 + "," + word2 + "," + frequency);
+                    }
+                    dictionary.setBigramAndGetFrequency(
+                            word1, word2, initializing ? new ForgettingCurveParams(true)
+                            : new ForgettingCurveParams(frequency, now, last));
+                }
+                mBigramList.addBigram(word1, word2, (byte)frequency);
+            }
+        };
+
+        // Load the dictionary from binary file
+        FileInputStream inStream = null;
+        try {
+            final File file = new File(getContext().getFilesDir(), fileName);
+            final byte[] buffer = new byte[(int)file.length()];
+            inStream = new FileInputStream(file);
+            inStream.read(buffer);
+            UserHistoryDictIOUtils.readDictionaryBinary(
+                    new ByteArrayWrapper(buffer), listener);
+        } catch (FileNotFoundException e) {
+            // This is an expected condition: we don't have a user history dictionary for this
+            // language yet. It will be created sometime later.
+        } catch (IOException e) {
+            Log.e(TAG, "IOException on opening a bytebuffer", e);
+        } finally {
+            if (inStream != null) {
+                try {
+                    inStream.close();
+                } catch (IOException e) {
+                    // do nothing
+                }
+            }
+            if (PROFILE_SAVE_RESTORE) {
+                final long diff = System.currentTimeMillis() - now;
+                Log.d(TAG, "PROF: Load UserHistoryDictionary: "
+                        + mLocale + ", " + diff + "ms. load " + profTotal + "entries.");
+            }
+        }
+    }
+
+    /**
+     * Async task to write pending words to the binarydicts.
+     */
+    private static final class UpdateBinaryTask extends AsyncTask<Void, Void, Void>
+            implements BigramDictionaryInterface {
+        private final UserHistoryDictionaryBigramList mBigramList;
+        private final boolean mAddLevel0Bigrams;
+        private final String mLocale;
+        private final UserHistoryDictionary mUserHistoryDictionary;
+        private final SharedPreferences mPrefs;
+        private final Context mContext;
+
+        public UpdateBinaryTask(final UserHistoryDictionaryBigramList pendingWrites,
+                final String locale, final UserHistoryDictionary dict,
+                final SharedPreferences prefs, final Context context) {
+            mBigramList = pendingWrites;
+            mLocale = locale;
+            mUserHistoryDictionary = dict;
+            mPrefs = prefs;
+            mContext = context;
+            mAddLevel0Bigrams = mBigramList.size() <= MAX_HISTORY_BIGRAMS;
+        }
+
+        @Override
+        protected Void doInBackground(final Void... v) {
+            if (mUserHistoryDictionary.isTest) {
+                // If isTest == true, wait until the lock is released.
+                mUserHistoryDictionary.mBigramListLock.lock();
+                try {
+                    doWriteTaskLocked();
+                } finally {
+                    mUserHistoryDictionary.mBigramListLock.unlock();
+                }
+            } else if (mUserHistoryDictionary.mBigramListLock.tryLock()) {
+                try {
+                    doWriteTaskLocked();
+                } finally {
+                    mUserHistoryDictionary.mBigramListLock.unlock();
+                }
+            }
+            return null;
+        }
+
+        private void doWriteTaskLocked() {
+            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) {
+                    Log.e(TAG, "In stress test", e);
+                }
+            }
+
+            final long now = PROFILE_SAVE_RESTORE ? System.currentTimeMillis() : 0;
+            final String fileName = NAME + "." + mLocale + ".dict";
+            final File file = new File(mContext.getFilesDir(), fileName);
+            FileOutputStream out = null;
+
+            try {
+                out = new FileOutputStream(file);
+                UserHistoryDictIOUtils.writeDictionaryBinary(out, this, mBigramList, VERSION3);
+                out.flush();
+                out.close();
+            } catch (IOException e) {
+                Log.e(TAG, "IO Exception while writing file", e);
+            } finally {
+                if (out != null) {
+                    try {
+                        out.close();
+                    } catch (IOException e) {
+                        // ignore
+                    }
+                }
+            }
+
+            // Save the timestamp after we finish writing the binary dictionary.
+            Settings.writeLastUserHistoryWriteTime(mPrefs, mLocale);
+            if (PROFILE_SAVE_RESTORE) {
+                final long diff = System.currentTimeMillis() - now;
+                Log.w(TAG, "PROF: Write User HistoryDictionary: " + mLocale + ", " + diff + "ms.");
+            }
+        }
+
+        @Override
+        public int getFrequency(final String word1, final String word2) {
+            final int freq;
+            if (word1 == null) { // unigram
+                freq = FREQUENCY_FOR_TYPED;
+                final byte prevFc = mBigramList.getBigrams(word1).get(word2);
+            } else { // bigram
+                final NextWord nw = mUserHistoryDictionary.getBigramWord(word1, word2);
+                if (nw != null) {
+                    final ForgettingCurveParams fcp = nw.getFcParams();
+                    final byte prevFc = mBigramList.getBigrams(word1).get(word2);
+                    final byte fc = fcp.getFc();
+                    final boolean isValid = fcp.isValid();
+                    if (prevFc > 0 && prevFc == fc) {
+                        freq = fc & 0xFF;
+                    } else if (UserHistoryForgettingCurveUtils.
+                            needsToSave(fc, isValid, mAddLevel0Bigrams)) {
+                        freq = fc & 0xFF;
+                    } else {
+                        // Delete this entry
+                        freq = -1;
+                    }
+                } else {
+                    // Delete this entry
+                    freq = -1;
+                }
+            }
+            return freq;
+        }
+    }
+
+    @UsedForTesting
+    /* package for test */ void forceAddWordForTest(
+            final String word1, final String word2, final boolean isValid) {
+        mBigramListLock.lock();
+        try {
+            addToUserHistory(word1, word2, isValid);
+        } finally {
+            mBigramListLock.unlock();
+        }
+    }
+}