summaryrefslogtreecommitdiffstats
path: root/src/com/android/launcher3/allapps/search/DefaultAppSearchAlgorithm.java
blob: 26f6ec357290188454c0e66841c16caee9a93b2e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
/*
 * Copyright (C) 2015 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.launcher3.allapps.search;

import android.os.Handler;

import com.android.launcher3.AppInfo;
import com.android.launcher3.util.ComponentKey;

import java.text.Collator;
import java.util.ArrayList;
import java.util.List;

/**
 * The default search implementation.
 */
public class DefaultAppSearchAlgorithm implements SearchAlgorithm {

    private final List<AppInfo> mApps;
    protected final Handler mResultHandler;

    public DefaultAppSearchAlgorithm(List<AppInfo> apps) {
        mApps = apps;
        mResultHandler = new Handler();
    }

    @Override
    public void cancel(boolean interruptActiveRequests) {
        if (interruptActiveRequests) {
            mResultHandler.removeCallbacksAndMessages(null);
        }
    }

    @Override
    public void doSearch(final String query,
            final AllAppsSearchBarController.Callbacks callback) {
        final ArrayList<ComponentKey> result = getTitleMatchResult(query);
        mResultHandler.post(new Runnable() {

            @Override
            public void run() {
                callback.onSearchResult(query, result);
            }
        });
    }

    private ArrayList<ComponentKey> getTitleMatchResult(String query) {
        // Do an intersection of the words in the query and each title, and filter out all the
        // apps that don't match all of the words in the query.
        final String queryTextLower = query.toLowerCase();
        final ArrayList<ComponentKey> result = new ArrayList<>();
        StringMatcher matcher = StringMatcher.getInstance();
        for (AppInfo info : mApps) {
            if (matches(info, queryTextLower, matcher)) {
                result.add(info.toComponentKey());
            }
        }
        return result;
    }

    public static boolean matches(AppInfo info, String query, StringMatcher matcher) {
        int queryLength = query.length();

        String title = info.title.toString();
        int titleLength = title.length();

        if (titleLength < queryLength || queryLength <= 0) {
            return false;
        }

        int lastType;
        int thisType = Character.UNASSIGNED;
        int nextType = Character.getType(title.codePointAt(0));

        int end = titleLength - queryLength;
        for (int i = 0; i <= end; i++) {
            lastType = thisType;
            thisType = nextType;
            nextType = i < (titleLength - 1) ?
                    Character.getType(title.codePointAt(i + 1)) : Character.UNASSIGNED;
            if (isBreak(thisType, lastType, nextType) &&
                    matcher.matches(query, title.substring(i, i + queryLength))) {
                return true;
            }
        }
        return false;
    }

    /**
     * Returns true if the current point should be a break point. Following cases
     * are considered as break points:
     *      1) Any non space character after a space character
     *      2) Any digit after a non-digit character
     *      3) Any capital character after a digit or small character
     *      4) Any capital character before a small character
     */
    private static boolean isBreak(int thisType, int prevType, int nextType) {
        switch (prevType) {
            case Character.UNASSIGNED:
            case Character.SPACE_SEPARATOR:
            case Character.LINE_SEPARATOR:
            case Character.PARAGRAPH_SEPARATOR:
                return true;
        }
        switch (thisType) {
            case Character.UPPERCASE_LETTER:
                if (nextType == Character.UPPERCASE_LETTER) {
                    return true;
                }
                // Follow through
            case Character.TITLECASE_LETTER:
                // Break point if previous was not a upper case
                return prevType != Character.UPPERCASE_LETTER;
            case Character.LOWERCASE_LETTER:
                // Break point if previous was not a letter.
                return prevType > Character.OTHER_LETTER || prevType <= Character.UNASSIGNED;
            case Character.DECIMAL_DIGIT_NUMBER:
            case Character.LETTER_NUMBER:
            case Character.OTHER_NUMBER:
                // Break point if previous was not a number
                return !(prevType == Character.DECIMAL_DIGIT_NUMBER
                        || prevType == Character.LETTER_NUMBER
                        || prevType == Character.OTHER_NUMBER);
            case Character.MATH_SYMBOL:
            case Character.CURRENCY_SYMBOL:
            case Character.OTHER_PUNCTUATION:
            case Character.DASH_PUNCTUATION:
                // Always a break point for a symbol
                return true;
            default:
                return  false;
        }
    }

    public static class StringMatcher {

        private static final char MAX_UNICODE = '\uFFFF';

        private final Collator mCollator;

        StringMatcher() {
            // On android N and above, Collator uses ICU implementation which has a much better
            // support for non-latin locales.
            mCollator = Collator.getInstance();
            mCollator.setStrength(Collator.PRIMARY);
            mCollator.setDecomposition(Collator.CANONICAL_DECOMPOSITION);
        }

        /**
         * Returns true if {@param query} is a prefix of {@param target}
         */
        public boolean matches(String query, String target) {
            switch (mCollator.compare(query, target)) {
                case 0:
                    return true;
                case -1:
                    // The target string can contain a modifier which would make it larger than
                    // the query string (even though the length is same). If the query becomes
                    // larger after appending a unicode character, it was originally a prefix of
                    // the target string and hence should match.
                    return mCollator.compare(query + MAX_UNICODE, target) > -1;
                default:
                    return false;
            }
        }

        public static StringMatcher getInstance() {
            return new StringMatcher();
        }
    }
}