yomichan/ext/js/templates/sandbox/template-renderer.js
toasted-nutbread 10a9da4d31
Anki template renderer abstraction (#1839)
* Add AnkiTemplateRenderer abstraction

* Move Anki-specific template functionality into AnkiTemplateRenderer

* Add documentation comments
2021-07-18 11:20:03 -04:00

144 lines
4.4 KiB
JavaScript

/*
* Copyright (C) 2016-2021 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/>.
*/
/* global
* Handlebars
*/
class TemplateRenderer {
constructor() {
this._cache = new Map();
this._cacheMaxSize = 5;
this._dataTypes = new Map();
this._renderSetup = null;
this._renderCleanup = null;
}
registerHelpers(helpers) {
Handlebars.partials = Handlebars.templates;
for (const [name, helper] of helpers) {
this._registerHelper(name, helper);
}
}
registerDataType(name, {modifier=null, composeData=null}) {
this._dataTypes.set(name, {modifier, composeData});
}
setRenderCallbacks(setup, cleanup) {
this._renderSetup = setup;
this._renderCleanup = cleanup;
}
render(template, data, type) {
const instance = this._getTemplateInstance(template);
data = this._getModifiedData(data, void 0, type);
return this._renderTemplate(instance, data);
}
renderMulti(items) {
const results = [];
for (const {template, templateItems} of items) {
const instance = this._getTemplateInstance(template);
for (const {type, commonData, datas} of templateItems) {
for (let data of datas) {
let result;
try {
data = this._getModifiedData(data, commonData, type);
result = this._renderTemplate(instance, data);
result = {result};
} catch (error) {
result = {error};
}
results.push(result);
}
}
}
return results;
}
getModifiedData(data, type) {
return this._getModifiedData(data, void 0, type);
}
// Private
_getTemplateInstance(template) {
const cache = this._cache;
let instance = cache.get(template);
if (typeof instance === 'undefined') {
this._updateCacheSize(this._cacheMaxSize - 1);
instance = Handlebars.compile(template);
cache.set(template, instance);
}
return instance;
}
_renderTemplate(instance, data) {
const renderSetup = this._renderSetup;
const renderCleanup = this._renderCleanup;
let result;
let additions1;
let additions2;
try {
additions1 = (typeof renderSetup === 'function' ? renderSetup(data) : null);
result = instance(data).trim();
} finally {
additions2 = (typeof renderCleanup === 'function' ? renderCleanup(data) : null);
}
return Object.assign({result}, additions1, additions2);
}
_getModifiedData(data, commonData, type) {
if (typeof type === 'string') {
const typeInfo = this._dataTypes.get(type);
if (typeof typeInfo !== 'undefined') {
if (typeof commonData !== 'undefined') {
const {composeData} = typeInfo;
if (typeof composeData === 'function') {
data = composeData(data, commonData);
}
}
const {modifier} = typeInfo;
if (typeof modifier === 'function') {
data = modifier(data);
}
}
}
return data;
}
_updateCacheSize(maxSize) {
const cache = this._cache;
let removeCount = cache.size - maxSize;
if (removeCount <= 0) { return; }
for (const key of cache.keys()) {
cache.delete(key);
if (--removeCount <= 0) { break; }
}
}
_registerHelper(name, helper) {
function wrapper(...args) {
return helper(this, ...args);
}
Handlebars.registerHelper(name, wrapper);
}
}