Implement getting X11 clipboard contents

CHANGELOG.md

@@ -45,6 +45,7 @@ You can find its changes [documented below](#070---2021-01-01).
 - X11: Add support for transparent windows ([#1803] by [@psychon])
 - X11: Added support for `get_monitors` ([#1804] by [@psychon])
 - `has_focus` method on `WidgetPod` ([#1825] by [@ForLoveOfCats])
+- x11: Add support for getting clipboard contents ([#1805] by [@psychon])
 
 ### Changed
 
@@ -734,6 +735,7 @@ Last release without a changelog :(
 [#1802]: https://github.com/linebender/druid/pull/1802
 [#1803]: https://github.com/linebender/druid/pull/1803
 [#1804]: https://github.com/linebender/druid/pull/1804
+[#1805]: https://github.com/linebender/druid/pull/1805
 [#1820]: https://github.com/linebender/druid/pull/1820
 [#1825]: https://github.com/linebender/druid/pull/1825
 

druid-shell/src/platform/x11/application.rs

@@ -14,8 +14,8 @@
 
 //! X11 implementation of features at the application scope.
 
-use std::cell::RefCell;
-use std::collections::HashMap;
+use std::cell::{Cell, RefCell};
+use std::collections::{HashMap, VecDeque};
 use std::convert::{TryFrom, TryInto};
 use std::os::unix::io::RawFd;
 use std::rc::Rc;
@@ -27,7 +27,7 @@ use x11rb::protocol::present::ConnectionExt as _;
 use x11rb::protocol::render::{self, ConnectionExt as _, Pictformat};
 use x11rb::protocol::xfixes::ConnectionExt as _;
 use x11rb::protocol::xproto::{
-    self, ConnectionExt, CreateWindowAux, EventMask, Visualtype, WindowClass,
+    self, ConnectionExt, CreateWindowAux, EventMask, Timestamp, Visualtype, WindowClass,
 };
 use x11rb::protocol::Event;
 use x11rb::resource_manager::Database as ResourceDb;
@@ -60,6 +60,8 @@ pub(crate) struct Application {
     root_visual_type: Visualtype,
     /// The visual for windows with transparent backgrounds, if supported
     argb_visual_type: Option<Visualtype>,
+    /// Pending events that need to be handled later
+    pending_events: Rc<RefCell<VecDeque<Event>>>,
 
     /// The X11 resource database used to query dpi.
     pub(crate) rdb: Rc<ResourceDb>,
@@ -74,7 +76,7 @@ pub(crate) struct Application {
     /// In practice multiple physical monitor drawing areas are present on a single screen.
     /// This is achieved via various X server extensions (XRandR/Xinerama/TwinView),
     /// with XRandR seeming like the best choice.
-    screen_num: i32, // Needs a container when no longer const
+    screen_num: usize, // Needs a container when no longer const
     /// The X11 window id of this `Application`.
     ///
     /// This is an input-only non-visual X11 window that is created first during initialization,
@@ -95,6 +97,8 @@ pub(crate) struct Application {
     present_opcode: Option<u8>,
     /// Support for the render extension in at least version 0.5?
     render_argb32_pictformat_cursor: Option<Pictformat>,
+    /// Newest timestamp that we received
+    timestamp: Rc<Cell<Timestamp>>,
 }
 
 /// The mutable `Application` state.
@@ -129,7 +133,7 @@ impl Application {
         let (conn, screen_num) = XCBConnection::connect(None)?;
         let rdb = Rc::new(ResourceDb::new_from_default(&conn)?);
         let connection = Rc::new(conn);
-        let window_id = Application::create_event_window(&connection, screen_num as i32)?;
+        let window_id = Application::create_event_window(&connection, screen_num)?;
         let state = Rc::new(RefCell::new(State {
             quitting: false,
             windows: HashMap::new(),
@@ -210,7 +214,7 @@ impl Application {
         Ok(Application {
             connection,
             rdb,
-            screen_num: screen_num as i32,
+            screen_num,
             window_id,
             state,
             idle_read,
@@ -219,8 +223,10 @@ impl Application {
             present_opcode,
             root_visual_type,
             argb_visual_type,
+            pending_events: Default::default(),
             marker: std::marker::PhantomData,
             render_argb32_pictformat_cursor,
+            timestamp: Rc::new(Cell::new(x11rb::CURRENT_TIME)),
         })
     }
 
@@ -277,12 +283,12 @@ impl Application {
         self.render_argb32_pictformat_cursor
     }
 
-    fn create_event_window(conn: &Rc<XCBConnection>, screen_num: i32) -> Result<u32, Error> {
+    fn create_event_window(conn: &Rc<XCBConnection>, screen_num: usize) -> Result<u32, Error> {
         let id = conn.generate_id()?;
         let setup = conn.setup();
         let screen = setup
             .roots
-            .get(screen_num as usize)
+            .get(screen_num)
             .ok_or_else(|| anyhow!("invalid screen num: {}", screen_num))?;
 
         // Create the actual window
@@ -343,7 +349,7 @@ impl Application {
 
     #[inline]
     pub(crate) fn screen_num(&self) -> i32 {
-        self.screen_num
+        self.screen_num as _
     }
 
     #[inline]
@@ -375,6 +381,21 @@ impl Application {
 
     /// Returns `Ok(true)` if we want to exit the main loop.
     fn handle_event(&self, ev: &Event) -> Result<bool, Error> {
+        if ev.server_generated() {
+            // Update our latest timestamp
+            let timestamp = match ev {
+                Event::KeyPress(ev) => ev.time,
+                Event::KeyRelease(ev) => ev.time,
+                Event::ButtonPress(ev) => ev.time,
+                Event::ButtonRelease(ev) => ev.time,
+                Event::MotionNotify(ev) => ev.time,
+                Event::EnterNotify(ev) => ev.time,
+                Event::LeaveNotify(ev) => ev.time,
+                Event::PropertyNotify(ev) => ev.time,
+                _ => self.timestamp.get(),
+            };
+            self.timestamp.set(timestamp);
+        }
         match ev {
             // NOTE: When adding handling for any of the following events,
             //       there must be a check against self.window_id
@@ -514,10 +535,15 @@ impl Application {
 
             self.connection.flush()?;
 
+            // Deal with pending events
+            let mut event = self.pending_events.borrow_mut().pop_front();
+
             // Before we poll on the connection's file descriptor, check whether there are any
             // events ready. It could be that XCB has some events in its internal buffers because
             // of something that happened during the idle loop.
-            let mut event = self.connection.poll_for_event()?;
+            if event.is_none() {
+                event = self.connection.poll_for_event()?;
+            }
 
             if event.is_none() {
                 poll_with_timeout(
@@ -607,9 +633,12 @@ impl Application {
     }
 
     pub fn clipboard(&self) -> Clipboard {
-        // TODO(x11/clipboard): implement Application::clipboard
-        tracing::warn!("Application::clipboard is currently unimplemented for X11 platforms.");
-        Clipboard {}
+        Clipboard::new(
+            Rc::clone(&self.connection),
+            self.screen_num,
+            Rc::clone(&self.pending_events),
+            Rc::clone(&self.timestamp),
+        )
     }
 
     pub fn get_locale() -> String {