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- Committer: Bazaar Package Importer
- Author(s): Bryce Harrington
- Date: 2011-02-21 18:35:33 UTC
- Revision ID: james.westby@ubuntu.com-20110221183533-4dm0eushai2b571k
Tags: upstream-0.1~git20101129.ac93a3d3
Import upstream version 0.1~git20101129.ac93a3d3
- files added:
- clients
- compositor
- data
- m4
- protocol
- spec
- wayland
added
removed
TODO
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Core wayland protocol
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- surface.set_grab_mode(GRAB_OWNER_EVENTS vs GRAB_SURFACE_EVENTS), to
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make menus work right: click and drag in a menubar grabs the
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pointer to the menubar (which we need for detecting motion into
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another menu item), but we need events for the popup menu surface
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as well.
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- The message format has to include information about number of fds
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in the message so we can skip a message correctly. Or we should
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just give up on trying to recover from unknown messages. We need
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to make sure you never get a message from an interface you don't
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know about (using per-client id space and subscribe) or include
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information on number of fds, so marshalling logic can skip.
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- generate pointer_focus (and drag focus) on raise/lower, move
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windows, all kinds of changes in surface stacking.
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- glyph cache
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buffer = drm.create_buffer(); /* buffer with stuff in it */
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cache.upload(buffer, x, y, width, height, int hash)
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drm.buffer: id, name, stride etc /* event to announce cache buffer */
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cache.image: hash, buffer, x, y, stride /* event to announce
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* location in cache */
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cache.reject: hash /* no upload for you! */
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cache.retire: buffer /* cache has stopped using buffer, please
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* reupload whatever you had in that buffer */
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- DnD issues:
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Root window must send NULL type (to decline drop) or
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x-wayland/root-something type if the source offers that. But the
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target deletes the drag_offer object when drag.pointer_focus leaves
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the surface...
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How do we animate the drag icon back to the drag origin in case of
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a failed drag?
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How to handle surfaces from clients that don't know about dnd or
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don't care? Maybe the dnd object should have a
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dnd.register_surface() method so clients can opt-in the surfaces
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that will participate in dnd. Or just assume client is not
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participating until we receive an accept request.
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- Selection/copy+paste
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- Similar to dnd, create a selection object for a device to offer
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selection data:
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selection = shell.create(input_device)
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Requests:
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- selection.offer(type)
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- selection.activate(time)
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- selection.destroy()
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Events:
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- selection.finish(type, fd)
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- selection.discard() /* somebody else took the selection */
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- Notes: no window owner, which seems to be mostly there as a way
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to identify the client and to allow None (instead of a release
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request). Possibly also to make the selection go away
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automatically when the window with the contents go away, or
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possibly as a way for the source to distinguish between multiple
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selections. Toolkits generally just create a dummy-toplevel for
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selections though.
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- Per-device selection. The selection is per device. Different
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keyboards copy and paste to different selections.
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- Selection offer object. Introduced just before a surface
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receives keyboard_focus event or when somebody claims the
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selection and on keyboard_focus? That way only keyboard_focus
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owner will know the types... limits pasting to the
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keyboard_focus surface.
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Requests:
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- selection_offer.receive(type, fd)
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Events:
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- selection_offer.offer(type)
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- selection_offer.keyboard_focus()
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- Pointer image issue:
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- A touch input device doesn't have a pointer; indicate that
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somehow.
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- Cursor themes, tie in with glyph/image cache.
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- copy-n-paste, store data in server (only one mime-type available)
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or do X style (content mime-type negotiation, but data goes away
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when client quits).
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- Discard buffer, as in "wayland discarded your buffer, it's no
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longer visible, you can stop updating it now.", reattach, as in "oh
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hey, I'm about to show your buffer that I threw away, what was it
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again?". for wayland system compositor vt switcing, for example,
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to be able to throw away the surfaces in the session we're
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switching away from. for minimized windows that we don't want live
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thumb nails for. etc.
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- Initial placement of surfaces. Guess we can do, 1)
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surface-relative (menus), 2) pointer-relative (tooltips and
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right-click menus) or 3) server-decides (all other top-levels).
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- Per client id space. Each client has an entire 32 bit id namespace
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to itself. On the server side, each struct wl_client has an object
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hash table. Object announcements use a server id space and clients
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must respond with subscribe request with a client id for the
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object. Part of wl_proxy_create_for_id():
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wl_display_subscribe(display, id, new_id, my_version);
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or maybe
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wl_display_bind(display, id, new_id, my_version);
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Fixes a few things:
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- Maps the global object into the client id space, lets client
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allocate the id. All ids are allocated by the client this way,
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which fixes the range protocol problem.
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- Tells the server that the client is interested in events from
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the object. Lets the server know that a client participates in a
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certain protocol (like drag and drop), so the server can account
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for whether or not the client is expected to reply
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- Server emits initial object state event(s) in reponse to
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receiving the subscribe request. Introduces an extra round trip
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at initialization time, but the server will still announces all
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objects in one burst and the client can subscribe in a burst as
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well.
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- Separates client resources, since each client will have it's own
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hash table. It's not longer possible to guess the id of another
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surface and access it.
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- Server must track the client id for each client an object is
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exposed to. In some cases we know this (a surface is always
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only owned by one client), in other cases it provides a way to
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track who's interested in the object events. For input device
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events, we can look up the client name when it receives pointer
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focus or keyboard focus and cache it in the device.
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- Server must know which id to send when passing object references
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in events. We could say that any object we're passing to a
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client must have a server id, and each client has a server id ->
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client id hash.
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- When a surface is the size of the screen and on top, we can set the
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scanout buffer to that surface directly. Like compiz unredirect
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top-level window feature. Except it won't have any protocol state
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side-effects and the client that owns the surface won't know. We
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lose control of updates. Should work well for X server root window
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under wayland. Should be possible for yuv overlays as well.
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- what about cursors then? maybe use hw cursors if the cursor
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satisfies hw limitations (64x64, only one cursor), switch to
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composited cursors if not.
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- clients needs to allocate the surface to be suitable for
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scanout, which they can do whenever they go fullscreen.
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- multihead, screen geometry and crtc layout protocol, hotplug, lcd
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subpixel info
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- a wayland settings protocol to tell clients about themes (icons,
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cursors, widget themes), fonts details (family, hinting
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preferences) etc. Just send all settings at connect time, send
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updates when a setting change. Getting a little close to gconf
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here, but could be pretty simple:
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interface "settings":
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event int_value(string name, int value)
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event string_value(string name, string value)
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but maybe it's better to just require that clients get that from
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somewhere else (gconf/dbus).
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- input device discovery, hotplug
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- Advertise axes as part of the discovery, use something like
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"org.wayland.input.x" to identify the axes.
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- keyboard state, layout events at connect time and when it
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changes, keyboard leds
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- relative events
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- multi touch?
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- synaptics, 3-button emulation, scim
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- auth; We need to generate a random socket name and advertise that
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on dbus along with a connection cookie. Something like a method
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that returns the socket name and a connection cookie. The
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connection cookie is just another random string that the client
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must pass to the wayland server to become authenticated. The
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Wayland server generates the cookie on demand when the dbus method
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is called and expires it after 5s or so.
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- or just pass the fd over dbus
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- drm bo access control, authentication, flink_to
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- Range protocol may not be sufficient... if a server cycles through
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2^32 object IDs we don't have a way to handle wrapping. And since
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we hand out a range of 256 IDs to each new clients, we're just
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talking about 2^24 clients. That's 31 years with a new client
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every minute... Maybe just use bigger ranges, then it's feasible
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to track and garbage collect them when a client dies.
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- Add protocol to let applications specify the effective/logical
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surface rectangle, that is, the edge of the window, ignoring drop
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shadows and other padding. The compositor needs this for snapping
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and constraining window motion. Also, maybe communicate the opaque
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region of the window (or just a conservative, simple estimate), to
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let the compositor reduce overdraw.
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- multi gpu, needs queue and seqno to wait on in requests
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Clients and ports
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- port gtk+
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- draw window decorations in gtkwindow.c
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- Details about pointer grabs. wayland doesn't have active grabs,
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menus will behave subtly different. Under X, clicking a menu
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open grabs the pointer and clicking outside the window pops down
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the menu and swallows the click. without active grabs we can't
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swallow the click. I'm sure there much more...
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- Port Qt? There's already talk about this on the list.
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- X on Wayland
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- move most of the code from xf86-video-intel into a Xorg wayland
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module.
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- don't ask KMS for available output and modes, use the info from
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the wayland server. then stop mooching off of drmmode.c.
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- map multiple wayland input devices to MPX in Xorg.
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- rootless; avoid allocating and setting the front buffer, draw
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window decorations in the X server (!), how to map input?
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- gnome-shell as a wayland session compositor
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- runs as a client of the wayland session compositor, uses
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clutter+egl on wayland
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- talks to an Xorg server as the compositing and window manager
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for that server and renders the output to a wayland surface.
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the Xorg server should be modified to take input from the system
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compositor through gnome-shell, but not allocate a front buffer.
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- make gnome-shell itself a nested wayland server and allow native
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wayland clients to connect and can native wayland windows with
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the windows from the X server.
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- qemu as a wayland client; session surface as X case
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- qemu has too simple acceleration, so a Wayland backend like the
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SDL/VNC ones it has now is trivial.
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- paravirt: forward wayland screen info as mmio, expose gem ioctls as mmio
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- mapping vmem is tricky, should try to only use ioctl (pwrite+pread)
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- not useful for Windows without a windows paravirt driver.
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- two approaches: 1) do a toplevel qemu window, or 2) expose a
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wayland server in the guest that forwards to the host wayland
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server, ie a "remote" compositor, but with the gem buffers
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shared. could do a wl_connection directly on mmio memory, with
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head and tail pointers. use an alloc_head register to indicate
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desired data to write, if it overwrites tail, block guest. just
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a socket would be easier.
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- moblin as a wayland compositor
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- clutter as a wayland compositors
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- argh, mutter
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