253aae15fc
Note how, in the current code, only *one* old history entry would ever be removed. That would mean that if e.g. the `cacheSize` is reduced, it would potentially require loading of multiple files before the database would be correctly pruned. Furthermore, in the case where the database was empty on load there's no need to attempt to shrink it, since trying to reduce the size of an *empty* array won't do much :-)
121 lines
3.4 KiB
JavaScript
121 lines
3.4 KiB
JavaScript
/* 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:
|
|
* - FIREFOX or 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) => {
|
|
let database = JSON.parse(databaseStr || '{}');
|
|
if (!('files' in database)) {
|
|
database.files = [];
|
|
} else {
|
|
while (database.files.length >= this.cacheSize) {
|
|
database.files.shift();
|
|
}
|
|
}
|
|
let index = -1;
|
|
for (let i = 0, length = database.files.length; i < length; i++) {
|
|
let 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;
|
|
});
|
|
}
|
|
|
|
_writeToStorage() {
|
|
return new Promise((resolve) => {
|
|
let databaseStr = JSON.stringify(this.database);
|
|
|
|
if (typeof PDFJSDev !== 'undefined' &&
|
|
PDFJSDev.test('FIREFOX || MOZCENTRAL')) {
|
|
sessionStorage.setItem('pdfjs.history', databaseStr);
|
|
} else {
|
|
localStorage.setItem('pdfjs.history', databaseStr);
|
|
}
|
|
resolve();
|
|
});
|
|
}
|
|
|
|
_readFromStorage() {
|
|
return new Promise(function(resolve) {
|
|
if (typeof PDFJSDev !== 'undefined' &&
|
|
PDFJSDev.test('FIREFOX || MOZCENTRAL')) {
|
|
resolve(sessionStorage.getItem('pdfjs.history'));
|
|
} else {
|
|
resolve(localStorage.getItem('pdfjs.history'));
|
|
}
|
|
});
|
|
}
|
|
|
|
set(name, val) {
|
|
return this._initializedPromise.then(() => {
|
|
this.file[name] = val;
|
|
return this._writeToStorage();
|
|
});
|
|
}
|
|
|
|
setMultiple(properties) {
|
|
return this._initializedPromise.then(() => {
|
|
for (let name in properties) {
|
|
this.file[name] = properties[name];
|
|
}
|
|
return this._writeToStorage();
|
|
});
|
|
}
|
|
|
|
get(name, defaultValue) {
|
|
return this._initializedPromise.then(() => {
|
|
let val = this.file[name];
|
|
return val !== undefined ? val : defaultValue;
|
|
});
|
|
}
|
|
|
|
getMultiple(properties) {
|
|
return this._initializedPromise.then(() => {
|
|
let values = Object.create(null);
|
|
|
|
for (let name in properties) {
|
|
let val = this.file[name];
|
|
values[name] = val !== undefined ? val : properties[name];
|
|
}
|
|
return values;
|
|
});
|
|
}
|
|
}
|
|
|
|
export {
|
|
ViewHistory,
|
|
};
|