yomichan/ext/mixed/js/audio-system.js
2020-04-18 14:23:34 -04:00

199 lines
5.9 KiB
JavaScript

/*
* Copyright (C) 2019-2020 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 TextToSpeechAudio {
constructor(text, voice) {
this.text = text;
this.voice = voice;
this._utterance = null;
this._volume = 1;
}
get currentTime() {
return 0;
}
set currentTime(value) {
// NOP
}
get volume() {
return this._volume;
}
set volume(value) {
this._volume = value;
if (this._utterance !== null) {
this._utterance.volume = value;
}
}
async play() {
try {
if (this._utterance === null) {
this._utterance = new SpeechSynthesisUtterance(this.text || '');
this._utterance.lang = 'ja-JP';
this._utterance.volume = this._volume;
this._utterance.voice = this.voice;
}
speechSynthesis.cancel();
speechSynthesis.speak(this._utterance);
} catch (e) {
// NOP
}
}
pause() {
try {
speechSynthesis.cancel();
} catch (e) {
// NOP
}
}
}
class AudioSystem {
constructor({audioUriBuilder, useCache}) {
this._cache = useCache ? new Map() : null;
this._cacheSizeMaximum = 32;
this._audioUriBuilder = audioUriBuilder;
if (typeof speechSynthesis !== 'undefined') {
// speechSynthesis.getVoices() will not be populated unless some API call is made.
speechSynthesis.addEventListener('voiceschanged', this._onVoicesChanged.bind(this));
}
}
async getDefinitionAudio(definition, sources, details) {
const key = `${definition.expression}:${definition.reading}`;
const hasCache = (this._cache !== null);
if (hasCache) {
const cacheValue = this._cache.get(key);
if (typeof cacheValue !== 'undefined') {
const {audio, uri, source} = cacheValue;
const index = sources.indexOf(source);
if (index >= 0) {
return {audio, uri, index};
}
}
}
for (let i = 0, ii = sources.length; i < ii; ++i) {
const source = sources[i];
const uri = await this._getAudioUri(definition, source, details);
if (uri === null) { continue; }
try {
const audio = await this._createAudio(uri);
if (hasCache) {
this._cacheCheck();
this._cache.set(key, {audio, uri, source});
}
return {audio, uri, index: i};
} catch (e) {
// NOP
}
}
throw new Error('Could not create audio');
}
createTextToSpeechAudio(text, voiceUri) {
const voice = this._getTextToSpeechVoiceFromVoiceUri(voiceUri);
if (voice === null) {
throw new Error('Invalid text-to-speech voice');
}
return new TextToSpeechAudio(text, voice);
}
_onVoicesChanged() {
// NOP
}
async _createAudio(uri) {
const ttsParameters = this._getTextToSpeechParameters(uri);
if (ttsParameters !== null) {
const {text, voiceUri} = ttsParameters;
return this.createTextToSpeechAudio(text, voiceUri);
}
return await this._createAudioFromUrl(uri);
}
_getAudioUri(definition, source, details) {
return (
this._audioUriBuilder !== null ?
this._audioUriBuilder.getUri(definition, source, details) :
null
);
}
_createAudioFromUrl(url) {
return new Promise((resolve, reject) => {
const audio = new Audio(url);
audio.addEventListener('loadeddata', () => {
const duration = audio.duration;
if (duration === 5.694694 || duration === 5.720718) {
// Hardcoded values for invalid audio
reject(new Error('Could not retrieve audio'));
} else {
resolve(audio);
}
});
audio.addEventListener('error', () => reject(audio.error));
});
}
_getTextToSpeechVoiceFromVoiceUri(voiceUri) {
try {
for (const voice of speechSynthesis.getVoices()) {
if (voice.voiceURI === voiceUri) {
return voice;
}
}
} catch (e) {
// NOP
}
return null;
}
_getTextToSpeechParameters(uri) {
const m = /^tts:[^#?]*\?([^#]*)/.exec(uri);
if (m === null) { return null; }
const searchParameters = new URLSearchParams(m[1]);
const text = searchParameters.get('text');
const voiceUri = searchParameters.get('voice');
return (text !== null && voiceUri !== null ? {text, voiceUri} : null);
}
_cacheCheck() {
const removeCount = this._cache.size - this._cacheSizeMaximum;
if (removeCount <= 0) { return; }
const removeKeys = [];
for (const key of this._cache.keys()) {
removeKeys.push(key);
if (removeKeys.length >= removeCount) { break; }
}
for (const key of removeKeys) {
this._cache.delete(key);
}
}
}