1/*
2 * Copyright (C) 2017 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.settings.inputmethod;
18
19import android.content.Context;
20import android.content.CursorLoader;
21import android.database.Cursor;
22import android.database.MatrixCursor;
23import android.provider.UserDictionary;
24import android.support.annotation.VisibleForTesting;
25import android.util.ArraySet;
26
27import java.util.Locale;
28import java.util.Objects;
29import java.util.Set;
30
31public class UserDictionaryCursorLoader extends CursorLoader {
32
33    @VisibleForTesting
34    static final String[] QUERY_PROJECTION = {
35            UserDictionary.Words._ID,
36            UserDictionary.Words.WORD,
37            UserDictionary.Words.SHORTCUT
38    };
39
40    // The index of the shortcut in the above array.
41    static final int INDEX_SHORTCUT = 2;
42
43    // Either the locale is empty (means the word is applicable to all locales)
44    // or the word equals our current locale
45    private static final String QUERY_SELECTION =
46            UserDictionary.Words.LOCALE + "=?";
47    private static final String QUERY_SELECTION_ALL_LOCALES =
48            UserDictionary.Words.LOCALE + " is null";
49
50
51    // Locale can be any of:
52    // - The string representation of a locale, as returned by Locale#toString()
53    // - The empty string. This means we want a cursor returning words valid for all locales.
54    // - null. This means we want a cursor for the current locale, whatever this is.
55    // Note that this contrasts with the data inside the database, where NULL means "all
56    // locales" and there should never be an empty string. The confusion is called by the
57    // historical use of null for "all locales".
58    // TODO: it should be easy to make this more readable by making the special values
59    // human-readable, like "all_locales" and "current_locales" strings, provided they
60    // can be guaranteed not to match locales that may exist.
61    private final String mLocale;
62
63    public UserDictionaryCursorLoader(Context context, String locale) {
64        super(context);
65        mLocale = locale;
66    }
67
68    @Override
69    public Cursor loadInBackground() {
70        final MatrixCursor result = new MatrixCursor(QUERY_PROJECTION);
71        final Cursor candidate;
72        if ("".equals(mLocale)) {
73            // Case-insensitive sort
74            candidate = getContext().getContentResolver().query(
75                    UserDictionary.Words.CONTENT_URI, QUERY_PROJECTION,
76                    QUERY_SELECTION_ALL_LOCALES, null,
77                    "UPPER(" + UserDictionary.Words.WORD + ")");
78        } else {
79            final String queryLocale = null != mLocale ? mLocale : Locale.getDefault().toString();
80            candidate = getContext().getContentResolver().query(UserDictionary.Words.CONTENT_URI,
81                    QUERY_PROJECTION, QUERY_SELECTION,
82                    new String[]{queryLocale}, "UPPER(" + UserDictionary.Words.WORD + ")");
83        }
84        final Set<Integer> hashSet = new ArraySet<>();
85        for (candidate.moveToFirst(); !candidate.isAfterLast(); candidate.moveToNext()) {
86            final int id = candidate.getInt(0);
87            final String word = candidate.getString(1);
88            final String shortcut = candidate.getString(2);
89            final int hash = Objects.hash(word, shortcut);
90            if (hashSet.contains(hash)) {
91                continue;
92            }
93            hashSet.add(hash);
94            result.addRow(new Object[]{id, word, shortcut});
95        }
96        return result;
97    }
98}
99