gecko-dev/remote/StreamRegistry.jsm
2019-12-16 16:17:47 +00:00

126 lines
2.8 KiB
JavaScript

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
"use strict";
var EXPORTED_SYMBOLS = ["StreamRegistry"];
const { XPCOMUtils } = ChromeUtils.import(
"resource://gre/modules/XPCOMUtils.jsm"
);
XPCOMUtils.defineLazyModuleGetters(this, {
AsyncShutdown: "resource://gre/modules/AsyncShutdown.jsm",
OS: "resource://gre/modules/osfile.jsm",
});
XPCOMUtils.defineLazyServiceGetters(this, {
uuidGen: ["@mozilla.org/uuid-generator;1", "nsIUUIDGenerator"],
});
const { UnsupportedError } = ChromeUtils.import(
"chrome://remote/content/Error.jsm"
);
class StreamRegistry {
constructor() {
// handle => stream
this.streams = new Map();
// Register an async shutdown blocker to ensure all open IO streams are
// closed, and remaining temporary files removed. Needs to happen before
// OS.File has been shutdown.
AsyncShutdown.profileBeforeChange.addBlocker(
"Remote Agent: Clean-up of open streams",
async () => {
await this.destructor();
}
);
}
async destructor() {
for (const stream of this.streams.values()) {
await this._discard(stream);
}
this.streams.clear();
}
async _discard(stream) {
if (stream instanceof OS.File) {
const fileInfo = await stream.stat();
stream.close();
// Also remove the temporary file
try {
await OS.File.remove(fileInfo.path, { ignoreAbsent: true });
} catch (e) {
console.error(`Failed to remove ${fileInfo.path}: ${e.message}`);
}
}
}
/**
* Add a new stream to the registry.
*
* @param {OS.File} stream
* Instance of the stream to add.
*
* @return {string}
* Stream handle (uuid)
*/
add(stream) {
let handle;
if (stream instanceof OS.File) {
handle = uuidGen
.generateUUID()
.toString()
.slice(1, -1);
} else {
// Bug 1602731 - Implement support for blob
throw new UnsupportedError(`Unknown stream type for ${stream}`);
}
this.streams.set(handle, stream);
return handle;
}
/**
* Get a stream from the registry.
*
* @param {string} handle
* Handle of the stream to retrieve.
*
* @return {OS.File}
* Requested stream
*/
get(handle) {
const stream = this.streams.get(handle);
if (!stream) {
throw new TypeError(`Invalid stream handle`);
}
return stream;
}
/**
* Remove a stream from the registry.
*
* @param {string} handle
* Handle of the stream to remove.
*
* @return {boolean}
* true if successfully removed
*/
async remove(handle) {
const stream = this.get(handle);
await this._discard(stream);
return this.streams.delete(handle);
}
}