Merge branch 'ewlsh/implicit-mainloop' into 'master'

[Mainloop 1/3] Add custom GSource for promise queueing

Closes #1

See merge request GNOME/gjs!557

1 files changed, 22 insertions, 0 deletions

diff --git a/doc/Custom-GSources.md b/doc/Custom-GSources.md
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+## Custom GSources
+
+GLib allows custom GSources to be added to the main loop.
+A custom GSource can control under what conditions it is dispatched.
+You can read more about GLib's main loop [here][glib-mainloop-docs].
+
+Within GJS, we have implemented a custom GSource to handle Promise execution.
+It dispatches whenever a Promise is queued, occurring before any other GLib
+events.
+This mimics the behavior of a [microtask queue](mdn-microtasks) in other
+JavaScript environments.
+You can read an introduction to building custom GSources within the archived
+developer documentation [here][custom-gsource-tutorial] or, if unavailable, via
+[the original source code][custom-gsource-tutorial-source].
+Another great resource is Philip Withnall's ["A detailed look at GSource"][gsource-blog-post]<sup>[[permalink]][gsource-blog-post-archive]</sup>.
+
+[gsource-blog-post]: https://tecnocode.co.uk/2015/05/05/a-detailed-look-at-gsource/
+[gsource-blog-post-archive]: https://web.archive.org/web/20201013000618/https://tecnocode.co.uk/2015/05/05/a-detailed-look-at-gsource/
+[mdn-microtasks]: https://developer.mozilla.org/en-US/docs/Web/API/HTML_DOM_API/Microtask_guide
+[glib-mainloop-docs]: https://docs.gtk.org/glib/main-loop.html#creating-new-source-types
+[custom-gsource-tutorial]: https://developer-old.gnome.org/gnome-devel-demos/unstable/custom-gsource.c.html.en
+[custom-gsource-tutorial-source]: https://gitlab.gnome.org/Archive/gnome-devel-docs/-/blob/703816cec292293fd337b6db8520b9b0afa7b3c9/platform-demos/C/custom-gsource.c.page