aboutsummaryrefslogtreecommitdiff
path: root/ext/mixed/js/object-property-accessor.js
blob: aedf6dcb8e65b2bdb2715f54cd68d20774d2418d (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
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
/*
 * Copyright (C) 2016-2020  Alex Yatskov <alex@foosoft.net>
 * Author: Alex Yatskov <alex@foosoft.net>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

/**
 * Class used to get and set generic properties of an object by using path strings.
 */
class ObjectPropertyAccessor {
    constructor(target, setter=null) {
        this._target = target;
        this._setter = (typeof setter === 'function' ? setter : null);
    }

    getProperty(pathArray, pathLength) {
        let target = this._target;
        const ii = typeof pathLength === 'number' ? Math.min(pathArray.length, pathLength) : pathArray.length;
        for (let i = 0; i < ii; ++i) {
            const key = pathArray[i];
            if (!ObjectPropertyAccessor.hasProperty(target, key)) {
                throw new Error(`Invalid path: ${ObjectPropertyAccessor.getPathString(pathArray.slice(0, i + 1))}`);
            }
            target = target[key];
        }
        return target;
    }

    setProperty(pathArray, value) {
        if (pathArray.length === 0) {
            throw new Error('Invalid path');
        }

        const target = this.getProperty(pathArray, pathArray.length - 1);
        const key = pathArray[pathArray.length - 1];
        if (!ObjectPropertyAccessor.isValidPropertyType(target, key)) {
            throw new Error(`Invalid path: ${ObjectPropertyAccessor.getPathString(pathArray)}`);
        }

        if (this._setter !== null) {
            this._setter(target, key, value, pathArray);
        } else {
            target[key] = value;
        }
    }

    static getPathString(pathArray) {
        const regexShort = /^[a-zA-Z_][a-zA-Z0-9_]*$/;
        let pathString = '';
        let first = true;
        for (let part of pathArray) {
            switch (typeof part) {
                case 'number':
                    if (Math.floor(part) !== part || part < 0) {
                        throw new Error('Invalid index');
                    }
                    part = `[${part}]`;
                    break;
                case 'string':
                    if (!regexShort.test(part)) {
                        const escapedPart = part.replace(/["\\]/g, '\\$&');
                        part = `["${escapedPart}"]`;
                    } else {
                        if (!first) {
                            part = `.${part}`;
                        }
                    }
                    break;
                default:
                    throw new Error(`Invalid type: ${typeof part}`);
            }
            pathString += part;
            first = false;
        }
        return pathString;
    }

    static getPathArray(pathString) {
        const pathArray = [];
        let state = 0;
        let quote = 0;
        let value = '';
        let escaped = false;
        for (const c of pathString) {
            const v = c.codePointAt(0);
            switch (state) {
                case 0: // Empty
                case 1: // Expecting identifier start
                    if (v === 0x5b) { // '['
                        if (state === 1) {
                            throw new Error(`Unexpected character: ${c}`);
                        }
                        state = 3;
                    } else if (
                        (v >= 0x41 && v <= 0x5a) || // ['A', 'Z']
                        (v >= 0x61 && v <= 0x7a) || // ['a', 'z']
                        v === 0x5f // '_'
                    ) {
                        state = 2;
                        value += c;
                    } else {
                        throw new Error(`Unexpected character: ${c}`);
                    }
                    break;
                case 2: // Identifier
                    if (
                        (v >= 0x41 && v <= 0x5a) || // ['A', 'Z']
                        (v >= 0x61 && v <= 0x7a) || // ['a', 'z']
                        (v >= 0x30 && v <= 0x39) || // ['0', '9']
                        v === 0x5f // '_'
                    ) {
                        value += c;
                    } else if (v === 0x5b) { // '['
                        pathArray.push(value);
                        value = '';
                        state = 3;
                    } else if (v === 0x2e) { // '.'
                        pathArray.push(value);
                        value = '';
                        state = 1;
                    } else {
                        throw new Error(`Unexpected character: ${c}`);
                    }
                    break;
                case 3: // Open bracket
                    if (v === 0x22 || v === 0x27) { // '"' or '\''
                        quote = v;
                        state = 4;
                    } else if (v >= 0x30 && v <= 0x39) { // ['0', '9']
                        state = 5;
                        value += c;
                    } else {
                        throw new Error(`Unexpected character: ${c}`);
                    }
                    break;
                case 4: // Quoted string
                    if (escaped) {
                        value += c;
                        escaped = false;
                    } else if (v === 0x5c) { // '\\'
                        escaped = true;
                    } else if (v !== quote) {
                        value += c;
                    } else {
                        state = 6;
                    }
                    break;
                case 5: // Number
                    if (v >= 0x30 && v <= 0x39) { // ['0', '9']
                        value += c;
                    } else if (v === 0x5d) { // ']'
                        pathArray.push(Number.parseInt(value, 10));
                        value = '';
                        state = 7;
                    } else {
                        throw new Error(`Unexpected character: ${c}`);
                    }
                    break;
                case 6: // Expecting closing bracket after quoted string
                    if (v === 0x5d) { // ']'
                        pathArray.push(value);
                        value = '';
                        state = 7;
                    } else {
                        throw new Error(`Unexpected character: ${c}`);
                    }
                    break;
                case 7: // Expecting . or [
                    if (v === 0x5b) { // '['
                        state = 3;
                    } else if (v === 0x2e) { // '.'
                        state = 1;
                    } else {
                        throw new Error(`Unexpected character: ${c}`);
                    }
                    break;
            }
        }
        switch (state) {
            case 0:
            case 7:
                break;
            case 2:
                pathArray.push(value);
                value = '';
                break;
            default:
                throw new Error('Path not terminated correctly');
        }
        return pathArray;
    }

    static hasProperty(object, property) {
        switch (typeof property) {
            case 'string':
                return (
                    typeof object === 'object' &&
                    object !== null &&
                    !Array.isArray(object) &&
                    Object.prototype.hasOwnProperty.call(object, property)
                );
            case 'number':
                return (
                    Array.isArray(object) &&
                    property >= 0 &&
                    property < object.length &&
                    property === Math.floor(property)
                );
            default:
                return false;
        }
    }

    static isValidPropertyType(object, property) {
        switch (typeof property) {
            case 'string':
                return (
                    typeof object === 'object' &&
                    object !== null &&
                    !Array.isArray(object)
                );
            case 'number':
                return (
                    Array.isArray(object) &&
                    property >= 0 &&
                    property === Math.floor(property)
                );
            default:
                return false;
        }
    }
}