Background: Message managers are used in JS code to communicate across potential process layers. There are two kinds of message managers, (a) frame message managers that correspond to windows and frames within those windows, and (b) process message managers that correspond to specific processes. Both kinds of message managers are organized in a hierarchy where parent message managers broadcast messages across their children.
Problem: In the case of multiple content processes (e.g. on FxOS/B2G), unintentional broadcasting is a serious performance and security footgun. Most (some would argue all) chrome code should only ever speak to specific frame and process message managers, and rarely (never) have to use broadcasting. This is currently not the case, however. We're going to fix offenders as we see them, but the fact that so many places in the codebase got it wrong has prompted us to make an API change. Change: In bug 776825, we're going to separate message managers into mere senders and broadcasters. Broadcasters have a different API, so it will be blatantly obvious when you're speaking to more than just one frame or process. We have fixed all call points in Gecko, and we will subsequently review every message broadcast as to whether using specific message senders is more appropriate. Code that has been written correctly should not be affected at all. This includes add-ons that load frame scripts and communicate with them without using broadcasting. Let us know if you have any questions. Philipp _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
