/* Copyright 2012 Mozilla Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
const DEFAULT_VIEW_HISTORY_CACHE_SIZE = 20
/**
* View History - This is a utility for saving various view parameters for
* recently opened files.
*
* The way that the view parameters are stored depends on how PDF.js is built,
* for 'gulp <flag>' the following cases exist:
* - MOZCENTRAL - uses sessionStorage.
* - GENERIC or CHROME - uses localStorage, if it is available.
*/
class ViewHistory {
constructor(fingerprint, cacheSize = DEFAULT_VIEW_HISTORY_CACHE_SIZE) {
this.fingerprint = fingerprint
this.cacheSize = cacheSize
this._initializedPromise = this._readFromStorage().then((databaseStr) => {
const database = JSON.parse(databaseStr || '{}')
let index = -1
if (!Array.isArray(database.files)) {
database.files = []
} else {
while (database.files.length >= this.cacheSize) {
database.files.shift()
}
for (let i = 0, ii = database.files.length; i < ii; i++) {
const branch = database.files[i]
if (branch.fingerprint === this.fingerprint) {
index = i
break
}
}
}
if (index === -1) {
index = database.files.push({ fingerprint: this.fingerprint }) - 1
}
this.file = database.files[index]
this.database = database
})
}
async _writeToStorage() {
const databaseStr = JSON.stringify(this.database)
if (typeof PDFJSDev !== 'undefined' && PDFJSDev.test('MOZCENTRAL')) {
sessionStorage.setItem('pdfjs.history', databaseStr)
return
}
localStorage.setItem('pdfjs.history', databaseStr)
}
async _readFromStorage() {
if (typeof PDFJSDev !== 'undefined' && PDFJSDev.test('MOZCENTRAL')) {
return sessionStorage.getItem('pdfjs.history')
}
return localStorage.getItem('pdfjs.history')
}
async set(name, val) {
await this._initializedPromise
this.file[name] = val
return this._writeToStorage()
}
async setMultiple(properties) {
await this._initializedPromise
for (const name in properties) {
this.file[name] = properties[name]
}
return this._writeToStorage()
}
async get(name, defaultValue) {
await this._initializedPromise
const val = this.file[name]
return val !== undefined ? val : defaultValue
}
async getMultiple(properties) {
await this._initializedPromise
const values = Object.create(null)
for (const name in properties) {
const val = this.file[name]
values[name] = val !== undefined ? val : properties[name]
}
return values
}
}
export { ViewHistory }