Rework event loop structure, stop using exceptions for termination

JuliaGL · Jun 10, 2022 · 66bc85a · 66bc85a
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commit 66bc85a
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Showing 7 changed files with 54 additions and 63 deletions.
diff --git a/.github/workflows/Test.yml b/.github/workflows/Test.yml
@@ -7,7 +7,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        julia-version: ['1.5', 'nightly']
+        julia-version: ['1.7', 'nightly']
         julia-arch: [x64, x86]
         os: [ubuntu-latest]
 

diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -0,0 +1,29 @@
+# Changelog for XCB.jl
+
+## Version `v0.5`
+
+- ![BREAKING][badge-breaking] ![Enhancement][badge-enhancement] `Base.run(::XWindowManager; kwargs...)` now only accepts a single keyword argument `sleep_time`, removing the ability to customize `execute_callback` and removing `poll` such that by default a mix of polling and (optionally) sleeping is done according to `sleep_time` (instead of either polling or calling a blocking C function). `iter_first` and `iter_last` keyword arguments are no longer available, and you should make your own event loop with `poll_event` and `process_event` if you want further customization.
+- ![BREAKING][badge-breaking] ![Enhancement][badge-enhancement] Closing a window is now done by returning a `CloseWindow` instance instead of throwing it as an exception. Note that it is still an `Exception`, so you can easily reproduce the old behavior with a manual `try`/`catch` block.
+- ![BREAKING][badge-breaking] ![Enhancement][badge-enhancement] The time field of `EventDetails` is now filled with the time since epoch, and not since the window has been created. You can always get the time since window creation yourself by recording `t0 = time()` when creating the window and subtracting it if desired.
+
+[badge-breaking]: https://img.shields.io/badge/BREAKING-red.svg
+[badge-deprecation]: https://img.shields.io/badge/deprecation-orange.svg
+[badge-feature]: https://img.shields.io/badge/feature-green.svg
+[badge-enhancement]: https://img.shields.io/badge/enhancement-blue.svg
+[badge-bugfix]: https://img.shields.io/badge/bugfix-purple.svg
+[badge-security]: https://img.shields.io/badge/security-black.svg
+[badge-experimental]: https://img.shields.io/badge/experimental-lightgrey.svg
+[badge-maintenance]: https://img.shields.io/badge/maintenance-gray.svg
+
+<!--
+# Badges (reused from the CHANGELOG.md of Documenter.jl)
+
+![BREAKING][badge-breaking]
+![Deprecation][badge-deprecation]
+![Feature][badge-feature]
+![Enhancement][badge-enhancement]
+![Bugfix][badge-bugfix]
+![Security][badge-security]
+![Experimental][badge-experimental]
+![Maintenance][badge-maintenance]
+-->
diff --git a/Project.toml b/Project.toml
@@ -1,6 +1,6 @@
 name = "XCB"
 uuid = "16167f82-ea26-5cba-b1de-ed6fd5e30a10"
-version = "0.4.1"
+version = "0.5.0"
 
 [deps]
 CEnum = "fa961155-64e5-5f13-b03f-caf6b980ea82"
@@ -17,10 +17,10 @@ CEnum = "0.4"
 DocStringExtensions = "0.8"
 Reexport = "1"
 UnPack = "1"
-WindowAbstractions = "0.4"
+WindowAbstractions = "0.5"
 Xorg_libxcb_jll = "1.13"
 Xorg_xcb_util_jll = "0.4"
-julia = "1.5"
+julia = "1.7"
 xkbcommon_jll = "0.9"
 
 [extras]

diff --git a/src/XCB.jl b/src/XCB.jl
@@ -28,6 +28,7 @@ import WindowAbstractions: set_title,
                            unmap_window,
                            wait_for_event,
                            poll_for_event,
+                           handle_event,
                            attach_graphics_context!,
                            get_window,
                            get_window_symbol,
@@ -67,7 +68,6 @@ export xcb,
        Setup,
        check,
        check_flush,
-       flush,
        current_screen,
        XCBWindow,
        GraphicsContext,

diff --git a/src/events.jl b/src/events.jl
@@ -13,12 +13,12 @@ response_type(data) = Int(data.response_type & 0x7f)
 
 is_from_send_request(data) = Bool(data.response_type & 0x80)
 
-function unsafe_load_event(xge_ptr; warn_unknown=false)
+function unsafe_load_event(xge_ptr)
     xge = unsafe_load(xge_ptr)
     rt = response_type(xge)
     et = event_type(Val(rt))
     if isnothing(et)
-        warn_unknown && @warn "Unknown event $(rt)"
+        @debug "Unknown event $(rt)"
         nothing
     else
         unsafe_load(convert(Ptr{et}, xge_ptr))
@@ -64,15 +64,13 @@ EventDetails(wm::XWindowManager, win::XCBWindow, data::xcb_expose_event_t, t) =
 EventDetails(wm::XWindowManager, win::XCBWindow, data::xcb_configure_notify_event_t, t) =
     EventDetails(win, ResizeEvent((data.width, data.height)), data, t)
 
-process_xevent(wm::XWindowManager, xge::Nothing, t) = nothing
-
-function process_xevent(wm::XWindowManager, event, t)
+function handle_event(wm::XWindowManager, event)
     if !isnothing(event) # event is known
         win = get_window(wm, event)
         if event isa xcb_client_message_event_t
             ed_8 = Int.(event.data.data8)
             event_data32_1 = ed_8[1] + ed_8[2] * 2^8 + ed_8[3] * 2^16 + ed_8[4] * 2^24
-            event_data32_1 == win.delete_request && throw(CloseWindow(win, ""))
+            event_data32_1 == win.delete_request && return CloseWindow(win, "")
             nothing
         elseif event isa xcb_xkb_state_notify_event_t
             xkb_state_update_mask(wm.keymap.state, event.baseMods, event.latchedMods, event.lockedMods, event.baseGroup, event.latchedGroup, event.lockedGroup)
@@ -81,48 +79,11 @@ function process_xevent(wm::XWindowManager, event, t)
             wm.keymap = Keymap(wm.conn; setup_xkb=false)
             nothing
         elseif !isnothing(win) # happened on an existing window
-            EventDetails(wm, win, event, t)
+            EventDetails(wm, win, event, time())
         else
             nothing
         end
     else
         nothing
     end
 end
-
-function listen_for_events(wm::XWindowManager, t0, next_event::Function, execute_callback; on_iter_first=() -> nothing, on_iter_last=() -> nothing, warn_unknown=false)
-    while !isempty(wm.windows)
-        try
-            on_iter_first()
-            xge = next_event(wm)
-            event = unsafe_load_event(xge; warn_unknown)
-            t = time() - t0
-            ed = process_xevent(wm, event, t)
-            !isnothing(ed) && execute_callback(ed)
-            on_iter_last()
-        catch e
-            if e isa WindowException
-                win_callbacks = callbacks(wm, e.win)
-                e isa CloseWindow && win_callbacks.on_close(wm, e)
-                e isa InvalidWindow && win_callbacks.on_invalid(wm, e)
-            else
-                rethrow(e)
-                break
-            end
-        end
-    end
-end
-
-"""
-Run an `EventLoop` attached to a `XWindowManager` instance.
-"""
-function Base.run(wm::XWindowManager, ::Synchronous, execute_callback = (ed) -> execute_callback(wm, ed); poll=false, kwargs...)
-    t0 = time()
-    next_event = poll ? poll_for_event : wait_for_event
-    listen_for_events(wm, t0, next_event, execute_callback; kwargs...)
-end
-
-function Base.run(wm::XWindowManager, ::Asynchronous, execute_callback = (ed) -> execute_callback(wm, ed); kwargs...)
-    t0 = time()
-    @async listen_for_events(wm, t0, poll_for_event, execute_callback; kwargs...)
-end
diff --git a/src/window_manager.jl b/src/window_manager.jl
@@ -33,24 +33,23 @@ function set_callbacks!(wm::XWindowManager, win::XCBWindow, callbacks::WindowCal
 end
 
 function poll_for_event(wm::XWindowManager)
-    while true
-        event = xcb_poll_for_event(wm.conn)
-        event ≠ C_NULL && return event
-        yield()
-    end
+    event = xcb_poll_for_event(wm.conn)
+    event == C_NULL && return nothing
+    unsafe_load_event(event)
 end
 
 function wait_for_event(wm::XWindowManager)
     event = xcb_wait_for_event(wm.conn)
-    event == C_NULL ? nothing : event
+    event == C_NULL && return nothing
+    unsafe_load_event(event)
 end
 
 function terminate_window!(wm::XWindowManager, win::XCBWindow)
     delete!(wm.windows, win.id)
     finalize(win)
 end
 
-get_window(wm::XWindowManager, id::Integer) = wm.windows[id]
+get_window(wm::XWindowManager, id::Integer) = get(wm.windows, id, nothing)
 get_window(wm::XWindowManager, event::xcb_xkb_state_notify_event_t) = nothing
 get_window(wm::XWindowManager, event::xcb_keymap_notify_event_t) = nothing
 get_window(wm::XWindowManager, event) = get_window(wm, window_id(event))

diff --git a/test/runtests.jl b/test/runtests.jl
@@ -1,6 +1,5 @@
 using XCB
 using Test
-using UnPack
 
 function on_button_pressed(details::EventDetails)
     x, y = details.location
@@ -12,15 +11,15 @@ function on_button_pressed(details::EventDetails)
 end
 
 function on_key_pressed(wm::XWindowManager, details::EventDetails)
-    @unpack win, data = details
+    (; win, data) = details
     send = XCB.send(wm, win)
     km = wm.keymap
     @info keystroke_info(km, details)
-    @unpack key_name, key, input, modifiers = data
+    (; key_name, key, input, modifiers) = data
     kc = KeyCombination(key, modifiers)
     set_title(win, "Random title $(rand())")
     if kc ∈ [key"q", key"ctrl+q", key"f4"]
-        throw(CloseWindow(win, "Received closing request from user input"))
+        CloseWindow(win, "Received closing request from user input")
     elseif kc == key"s"
         curr_extent = XCB.extent(win)
         XCB.set_extent(win, curr_extent .+ 1)
@@ -66,7 +65,7 @@ function test()
 
     if is_xvfb
         @info "- Running window asynchronously"
-        task = run(wm, Asynchronous(); warn_unknown=true)
+        task = @async run(wm)
         @info "- Sending fake inputs"
         send(MouseEvent(ButtonLeft(), MouseState(), ButtonPressed()))
         send(MouseEvent(ButtonLeft(), MouseState(), ButtonReleased()))
@@ -77,9 +76,12 @@ function test()
         send(key_event_from_name(wm.keymap, :AC04, KeyModifierState(), KeyPressed()))
         @info "- Waiting for window to close"
         wait(task)
+        @test !istaskfailed(task)
     else
-        run(wm, Synchronous(); warn_unknown=true, poll=false)
+        run(wm)
     end
 end
 
-test()
+@testset "XCB.jl" begin
+    @test isnothing(test())
+end;