1/*
2 * Copyright (C) 2013 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.inputmethod.latin.personalization;
18
19import android.content.Context;
20
21import com.android.inputmethod.annotations.ExternallyReferenced;
22import com.android.inputmethod.annotations.UsedForTesting;
23import com.android.inputmethod.latin.BinaryDictionary;
24import com.android.inputmethod.latin.Dictionary;
25import com.android.inputmethod.latin.ExpandableBinaryDictionary;
26import com.android.inputmethod.latin.NgramContext;
27import com.android.inputmethod.latin.define.DecoderSpecificConstants;
28import com.android.inputmethod.latin.define.ProductionFlags;
29import com.android.inputmethod.latin.makedict.DictionaryHeader;
30
31import java.io.File;
32import java.util.Locale;
33import java.util.Map;
34
35import javax.annotation.Nonnull;
36import javax.annotation.Nullable;
37
38/**
39 * Locally gathers statistics about the words user types and various other signals like
40 * auto-correction cancellation or manual picks. This allows the keyboard to adapt to the
41 * typist over time.
42 */
43public class UserHistoryDictionary extends ExpandableBinaryDictionary {
44    static final String NAME = UserHistoryDictionary.class.getSimpleName();
45
46    // TODO: Make this constructor private
47    UserHistoryDictionary(final Context context, final Locale locale,
48            @Nullable final String account) {
49        super(context, getUserHistoryDictName(NAME, locale, null /* dictFile */, account), locale, Dictionary.TYPE_USER_HISTORY, null);
50        if (mLocale != null && mLocale.toString().length() > 1) {
51            reloadDictionaryIfRequired();
52        }
53    }
54
55    /**
56     * @returns the name of the {@link UserHistoryDictionary}.
57     */
58    @UsedForTesting
59    static String getUserHistoryDictName(final String name, final Locale locale,
60            @Nullable final File dictFile, @Nullable final String account) {
61        if (!ProductionFlags.ENABLE_PER_ACCOUNT_USER_HISTORY_DICTIONARY) {
62            return getDictName(name, locale, dictFile);
63        }
64        return getUserHistoryDictNamePerAccount(name, locale, dictFile, account);
65    }
66
67    /**
68     * Uses the currently signed in account to determine the dictionary name.
69     */
70    private static String getUserHistoryDictNamePerAccount(final String name, final Locale locale,
71            @Nullable final File dictFile, @Nullable final String account) {
72        if (dictFile != null) {
73            return dictFile.getName();
74        }
75        String dictName = name + "." + locale.toString();
76        if (account != null) {
77            dictName += "." + account;
78        }
79        return dictName;
80    }
81
82    // Note: This method is called by {@link DictionaryFacilitator} using Java reflection.
83    @SuppressWarnings("unused")
84    @ExternallyReferenced
85    public static UserHistoryDictionary getDictionary(final Context context, final Locale locale,
86            final File dictFile, final String dictNamePrefix, @Nullable final String account) {
87        return PersonalizationHelper.getUserHistoryDictionary(context, locale, account);
88    }
89
90    /**
91     * Add a word to the user history dictionary.
92     *
93     * @param userHistoryDictionary the user history dictionary
94     * @param ngramContext the n-gram context
95     * @param word the word the user inputted
96     * @param isValid whether the word is valid or not
97     * @param timestamp the timestamp when the word has been inputted
98     */
99    public static void addToDictionary(final ExpandableBinaryDictionary userHistoryDictionary,
100            @Nonnull final NgramContext ngramContext, final String word, final boolean isValid,
101            final int timestamp) {
102        if (word.length() > BinaryDictionary.DICTIONARY_MAX_WORD_LENGTH) {
103            return;
104        }
105        userHistoryDictionary.updateEntriesForWord(ngramContext, word,
106                isValid, 1 /* count */, timestamp);
107    }
108
109    @Override
110    public void close() {
111        // Flush pending writes.
112        asyncFlushBinaryDictionary();
113        super.close();
114    }
115
116    @Override
117    protected Map<String, String> getHeaderAttributeMap() {
118        final Map<String, String> attributeMap = super.getHeaderAttributeMap();
119        attributeMap.put(DictionaryHeader.USES_FORGETTING_CURVE_KEY,
120                DictionaryHeader.ATTRIBUTE_VALUE_TRUE);
121        attributeMap.put(DictionaryHeader.HAS_HISTORICAL_INFO_KEY,
122                DictionaryHeader.ATTRIBUTE_VALUE_TRUE);
123        return attributeMap;
124    }
125
126    @Override
127    protected void loadInitialContentsLocked() {
128        // No initial contents.
129    }
130
131    @Override
132    public boolean isValidWord(final String word) {
133        // Strings out of this dictionary should not be considered existing words.
134        return false;
135    }
136}
137