yomichan/ext/js/templates/template-patcher.js

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/*
* Copyright (C) 2021 Yomichan Authors
*
* 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 TemplatePatcher {
constructor() {
this._diffPattern1 = /\n?\{\{<<<<<<<\}\}\n/g;
this._diffPattern2 = /\n\{\{=======\}\}\n/g;
this._diffPattern3 = /\n\{\{>>>>>>>\}\}\n*/g;
this._lookupMarkerPattern = /[ \t]*\{\{~?>\s*\(\s*lookup\s*\.\s*"marker"\s*\)\s*~?\}\}/g;
}
parsePatch(content) {
const diffPattern1 = this._diffPattern1;
const diffPattern2 = this._diffPattern2;
const diffPattern3 = this._diffPattern3;
const modifications = [];
let index = 0;
while (true) {
// Find modification boundaries
diffPattern1.lastIndex = index;
const m1 = diffPattern1.exec(content);
if (m1 === null) { break; }
diffPattern2.lastIndex = m1.index + m1[0].length;
const m2 = diffPattern2.exec(content);
if (m2 === null) { break; }
diffPattern3.lastIndex = m2.index + m2[0].length;
const m3 = diffPattern3.exec(content);
if (m3 === null) { break; }
// Construct
const current = content.substring(m1.index + m1[0].length, m2.index);
const replacement = content.substring(m2.index + m2[0].length, m3.index);
if (current.length > 0) {
modifications.push({current, replacement});
}
// Update
content = content.substring(0, m1.index) + content.substring(m3.index + m3[0].length);
index = m1.index;
}
return {addition: content, modifications};
}
applyPatch(template, patch) {
for (const {current, replacement} of patch.modifications) {
let fromIndex = 0;
while (true) {
const index = template.indexOf(current, fromIndex);
if (index < 0) { break; }
template = template.substring(0, index) + replacement + template.substring(index + current.length);
fromIndex = index + replacement.length;
}
}
template = this._addFieldTemplatesBeforeEnd(template, patch.addition);
return template;
}
// Private
_addFieldTemplatesBeforeEnd(template, addition) {
if (addition.length === 0) { return template; }
const newline = '\n';
let replaced = false;
template = template.replace(this._lookupMarkerPattern, (g0) => {
replaced = true;
return `${addition}${newline}${g0}`;
});
if (!replaced) {
template += newline;
template += addition;
}
return template;
}
}