electron/atom/browser/lib/objects-registry.js
2016-02-22 15:24:18 +08:00

88 lines
2.2 KiB
JavaScript

'use strict';
const v8Util = process.atomBinding('v8_util');
class ObjectsRegistry {
constructor() {
this.nextId = 0;
// Stores all objects by ref-counting.
// (id) => {object, count}
this.storage = {};
// Stores the IDs of objects referenced by WebContents.
// (webContentsId) => [id]
this.owners = {};
}
// Register a new object and return its assigned ID. If the object is already
// registered then the already assigned ID would be returned.
add(webContentsId, obj) {
// Get or assign an ID to the object.
let id = this.saveToStorage(obj);
// Add object to the set of referenced objects.
let owner = this.owners[webContentsId];
if (!owner)
owner = this.owners[webContentsId] = new Set();
if (!owner.has(id)) {
owner.add(id);
// Increase reference count if not referenced before.
this.storage[id].count++;
}
return id;
}
// Get an object according to its ID.
get(id) {
return this.storage[id].object;
}
// Dereference an object according to its ID.
remove(webContentsId, id) {
// Dereference from the storage.
this.dereference(id);
// Also remove the reference in owner.
this.owners[webContentsId].delete(id);
}
// Clear all references to objects refrenced by the WebContents.
clear(webContentsId) {
let owner = this.owners[webContentsId];
if (!owner)
return;
for (let id of owner)
this.dereference(id);
delete this.owners[webContentsId];
}
// Private: Saves the object into storage and assigns an ID for it.
saveToStorage(object) {
let id = v8Util.getHiddenValue(object, 'atomId');
if (!id) {
id = ++this.nextId;
this.storage[id] = {
count: 0,
object: object
};
v8Util.setHiddenValue(object, 'atomId', id);
}
return id;
}
// Private: Dereference the object from store.
dereference(id) {
let pointer = this.storage[id];
if (pointer == null) {
return;
}
pointer.count -= 1;
if (pointer.count === 0) {
v8Util.deleteHiddenValue(pointer.object, 'atomId');
return delete this.storage[id];
}
}
}
module.exports = new ObjectsRegistry;