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authortoasted-nutbread <toasted-nutbread@users.noreply.github.com>2020-03-15 22:23:32 -0400
committerGitHub <noreply@github.com>2020-03-15 22:23:32 -0400
commit7c5b64f9a43e9d2ca0c6d38cb5089be04c4c00df (patch)
treeed0274170739a3a45a07f0ad524ec4a92b38db0e /ext/mixed/js
parent6182b53142cb99d7f52cf99a3c25bb4e688ba447 (diff)
parent4b699a6b46869d5766f331d863aea38374ece50a (diff)
Merge pull request #406 from toasted-nutbread/object-property-accessor
Object property accessor
Diffstat (limited to 'ext/mixed/js')
-rw-r--r--ext/mixed/js/object-property-accessor.js244
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..108afc0d
--- /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: ${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 = 'empty';
+ let quote = 0;
+ let value = '';
+ let escaped = false;
+ for (const c of pathString) {
+ const v = c.codePointAt(0);
+ switch (state) {
+ case 'empty': // Empty
+ case 'id-start': // Expecting identifier start
+ if (v === 0x5b) { // '['
+ if (state === 'id-start') {
+ throw new Error(`Unexpected character: ${c}`);
+ }
+ state = 'open-bracket';
+ } else if (
+ (v >= 0x41 && v <= 0x5a) || // ['A', 'Z']
+ (v >= 0x61 && v <= 0x7a) || // ['a', 'z']
+ v === 0x5f // '_'
+ ) {
+ state = 'id';
+ value += c;
+ } else {
+ throw new Error(`Unexpected character: ${c}`);
+ }
+ break;
+ case 'id': // 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 = 'open-bracket';
+ } else if (v === 0x2e) { // '.'
+ pathArray.push(value);
+ value = '';
+ state = 'id-start';
+ } else {
+ throw new Error(`Unexpected character: ${c}`);
+ }
+ break;
+ case 'open-bracket': // Open bracket
+ if (v === 0x22 || v === 0x27) { // '"' or '\''
+ quote = v;
+ state = 'string';
+ } else if (v >= 0x30 && v <= 0x39) { // ['0', '9']
+ state = 'number';
+ value += c;
+ } else {
+ throw new Error(`Unexpected character: ${c}`);
+ }
+ break;
+ case 'string': // Quoted string
+ if (escaped) {
+ value += c;
+ escaped = false;
+ } else if (v === 0x5c) { // '\\'
+ escaped = true;
+ } else if (v !== quote) {
+ value += c;
+ } else {
+ state = 'close-bracket';
+ }
+ break;
+ case 'number': // Number
+ if (v >= 0x30 && v <= 0x39) { // ['0', '9']
+ value += c;
+ } else if (v === 0x5d) { // ']'
+ pathArray.push(Number.parseInt(value, 10));
+ value = '';
+ state = 'next';
+ } else {
+ throw new Error(`Unexpected character: ${c}`);
+ }
+ break;
+ case 'close-bracket': // Expecting closing bracket after quoted string
+ if (v === 0x5d) { // ']'
+ pathArray.push(value);
+ value = '';
+ state = 'next';
+ } else {
+ throw new Error(`Unexpected character: ${c}`);
+ }
+ break;
+ case 'next': // Expecting . or [
+ if (v === 0x5b) { // '['
+ state = 'open-bracket';
+ } else if (v === 0x2e) { // '.'
+ state = 'id-start';
+ } else {
+ throw new Error(`Unexpected character: ${c}`);
+ }
+ break;
+ }
+ }
+ switch (state) {
+ case 'empty':
+ case 'next':
+ break;
+ case 'id':
+ 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;
+ }
+ }
+}