65 lines
1.9 KiB
JavaScript
65 lines
1.9 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";
|
|
|
|
module.metadata = {
|
|
"stability": "experimental"
|
|
};
|
|
|
|
// This module provides `marshal` and `demarshal` functions
|
|
// that can be used to send MessagePort's over `nsIFrameMessageManager`
|
|
// until Bug 914974 is fixed.
|
|
|
|
const { add, iterator } = require("../sdk/lang/weak-set");
|
|
const { curry } = require("../sdk/lang/functional");
|
|
|
|
var id = 0;
|
|
const ports = new WeakMap();
|
|
|
|
// Takes `nsIFrameMessageManager` and `MessagePort` instances
|
|
// and returns a handle representing given `port`. Messages
|
|
// received on given `port` will be forwarded to a message
|
|
// manager under `sdk/port/message` and messages like:
|
|
// { port: { type: "MessagePort", id: 2}, data: data }
|
|
// Where id is an identifier associated with a given `port`
|
|
// and `data` is an `event.data` received on port.
|
|
const marshal = curry((manager, port) => {
|
|
if (!ports.has(port)) {
|
|
id = id + 1;
|
|
const handle = {type: "MessagePort", id: id};
|
|
// Bind id to the given port
|
|
ports.set(port, handle);
|
|
|
|
// Obtain a weak reference to a port.
|
|
add(exports, port);
|
|
|
|
port.onmessage = event => {
|
|
manager.sendAsyncMessage("sdk/port/message", {
|
|
port: handle,
|
|
message: event.data
|
|
});
|
|
};
|
|
|
|
return handle;
|
|
}
|
|
return ports.get(port);
|
|
});
|
|
exports.marshal = marshal;
|
|
|
|
// Takes `nsIFrameMessageManager` instance and a handle returned
|
|
// `marshal(manager, port)` returning a `port` that was passed
|
|
// to it. Note that `port` may be GC-ed in which case returned
|
|
// value will be `null`.
|
|
const demarshal = curry((manager, {type, id}) => {
|
|
if (type === "MessagePort") {
|
|
for (let port of iterator(exports)) {
|
|
if (id === ports.get(port).id)
|
|
return port;
|
|
}
|
|
}
|
|
return null;
|
|
});
|
|
exports.demarshal = demarshal;
|