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| -rw-r--r-- | ext/mixed/js/object-property-accessor.js | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/ext/mixed/js/object-property-accessor.js b/ext/mixed/js/object-property-accessor.js new file mode 100644 index 00000000..6b5f9678 --- /dev/null +++ b/ext/mixed/js/object-property-accessor.js @@ -0,0 +1,244 @@ +/* + * 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: ${this.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: ${this.getPathString(pathArray)}`); + } + + if (this._setter !== null) { + this._setter(target, key, value, pathArray); + } else { + target[key] = value; + } + } + + static getPathString(pathArray) { + const regexShort = /^[a-zA-Z_][a-zA-Z0-9_]*$/; + 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; + } + } +} |