Dispatch touch events and perform default touch actions.

This is currently limited to simple single-touch actions. It does not include
momentum scrolling or pinch zooming.

4 files changed, 174 insertions, 12 deletions

diff --git a/components/compositing/compositor.rs b/components/compositing/compositor.rs
index 0097d70b9de..0b44a715e88 100644
--- a/components/compositing/compositor.rs
+++ b/components/compositing/compositor.rs
@@ -26,7 +26,7 @@ use layers::rendergl;
 use layers::rendergl::RenderContext;
 use layers::scene::Scene;
 use layout_traits::LayoutControlChan;
-use msg::compositor_msg::{Epoch, FrameTreeId, LayerId, LayerKind};
+use msg::compositor_msg::{Epoch, EventResult, FrameTreeId, LayerId, LayerKind};
 use msg::compositor_msg::{LayerProperties, ScrollPolicy};
 use msg::constellation_msg::Msg as ConstellationMsg;
 use msg::constellation_msg::{AnimationState, Image, PixelFormat};
@@ -35,7 +35,8 @@ use msg::constellation_msg::{NavigationDirection, PipelineId, WindowSizeData};
 use pipeline::CompositionPipeline;
 use profile_traits::mem::{self, ReportKind, Reporter, ReporterRequest};
 use profile_traits::time::{self, ProfilerCategory, profile};
-use script_traits::{ConstellationControlMsg, LayoutControlMsg};
+use script_traits::CompositorEvent::{TouchDownEvent, TouchMoveEvent, TouchUpEvent};
+use script_traits::{ConstellationControlMsg, LayoutControlMsg, MouseButton};
 use scrolling::ScrollingTimerProxy;
 use std::collections::hash_map::Entry::{Occupied, Vacant};
 use std::collections::{HashMap, HashSet};
@@ -59,6 +60,9 @@ const BUFFER_MAP_SIZE: usize = 10000000;
 const MAX_ZOOM: f32 = 8.0;
 const MIN_ZOOM: f32 = 0.1;
 
+/// Minimum number of ScreenPx to begin touch scrolling.
+const TOUCH_PAN_MIN_SCREEN_PX: f32 = 20.0;
+
 /// Holds the state when running reftests that determines when it is
 /// safe to save the output image.
 #[derive(Copy, Clone, PartialEq)]
@@ -68,6 +72,23 @@ enum ReadyState {
     ReadyToSaveImage,
 }
 
+/// The states of the touch input state machine.
+///
+/// TODO: Currently Add support for "flinging" (scrolling inertia), pinch zooming, better
+/// support for multiple touch points.
+enum TouchState {
+    /// Not tracking any touch point
+    Nothing,
+    /// A touchstart event was dispatched to the page, but the response wasn't received yet.
+    WaitingForScript,
+    /// Script is consuming the current touch point; don't perform default actions.
+    DefaultPrevented,
+    /// A single touch point is active and may perform click or pan default actions.
+    Touching,
+    /// A single touch point is active and has started panning.
+    Panning,
+}
+
 /// NB: Never block on the constellation, because sometimes the constellation blocks on us.
 pub struct IOCompositor<Window: WindowMethods> {
     /// The application window.
@@ -156,6 +177,15 @@ pub struct IOCompositor<Window: WindowMethods> {
     /// Pending scroll to fragment event, if any
     fragment_point: Option<Point2D<f32>>,
 
+    /// Touch input state machine
+    touch_gesture_state: TouchState,
+
+    /// When tracking a touch for gesture detection, the point where it started
+    first_touch_point: Option<TypedPoint2D<DevicePixel, f32>>,
+
+    /// When tracking a touch for gesture detection, its most recent point
+    last_touch_point: Option<TypedPoint2D<DevicePixel, f32>>,
+
     /// Pending scroll events.
     pending_scroll_events: Vec<ScrollEvent>,
 
@@ -295,6 +325,9 @@ impl<Window: WindowMethods> IOCompositor<Window> {
             channel_to_self: state.sender.clone_compositor_proxy(),
             scrolling_timer: ScrollingTimerProxy::new(state.sender),
             composition_request: CompositionRequest::NoCompositingNecessary,
+            touch_gesture_state: TouchState::Nothing,
+            first_touch_point: None,
+            last_touch_point: None,
             pending_scroll_events: Vec::new(),
             composite_target: composite_target,
             shutdown_state: ShutdownState::NotShuttingDown,
@@ -502,6 +535,18 @@ impl<Window: WindowMethods> IOCompositor<Window> {
                 }
             }
 
+            (Msg::TouchEventProcessed(result), ShutdownState::NotShuttingDown) => {
+                match self.touch_gesture_state {
+                    TouchState::WaitingForScript => {
+                        self.touch_gesture_state = match result {
+                            EventResult::DefaultAllowed => TouchState::Touching,
+                            EventResult::DefaultPrevented => TouchState::DefaultPrevented,
+                        };
+                    }
+                    _ => {}
+                }
+            }
+
             (Msg::SetCursor(cursor), ShutdownState::NotShuttingDown) => {
                 self.window.set_cursor(cursor)
             }
@@ -1097,6 +1142,109 @@ impl<Window: WindowMethods> IOCompositor<Window> {
         }
     }
 
+    fn on_touch_down(&mut self, identifier: i32, point: TypedPoint2D<DevicePixel, f32>) {
+        match self.touch_gesture_state {
+            TouchState::Nothing => {
+                // TODO: Don't wait for script if we know the page has no touch event listeners.
+                self.first_touch_point = Some(point);
+                self.last_touch_point = Some(point);
+                self.touch_gesture_state = TouchState::WaitingForScript;
+            }
+            TouchState::WaitingForScript => {
+                // TODO: Queue events while waiting for script?
+            }
+            TouchState::DefaultPrevented => {}
+            TouchState::Touching => {}
+            TouchState::Panning => {}
+        }
+        if let Some(result) = self.find_topmost_layer_at_point(point / self.scene.scale) {
+            result.layer.send_event(self, TouchDownEvent(identifier, result.point.to_untyped()));
+        }
+    }
+
+    fn on_touch_move(&mut self, identifier: i32, point: TypedPoint2D<DevicePixel, f32>) {
+        match self.touch_gesture_state {
+            TouchState::Nothing => warn!("Got unexpected touch move event"),
+
+            TouchState::WaitingForScript => {
+                // TODO: Queue events while waiting for script?
+            }
+            TouchState::Touching => {
+                match self.first_touch_point {
+                    Some(p0) => {
+                        let delta = point - p0;
+                        let px: TypedPoint2D<ScreenPx, _> = delta / self.device_pixels_per_screen_px();
+                        let px = px.to_untyped();
+
+                        if px.x.abs() > TOUCH_PAN_MIN_SCREEN_PX ||
+                           px.y.abs() > TOUCH_PAN_MIN_SCREEN_PX
+                        {
+                            self.touch_gesture_state = TouchState::Panning;
+                            self.on_scroll_window_event(delta, point.cast().unwrap());
+                        }
+                    }
+                    None => warn!("first_touch_point not set")
+                }
+            }
+            TouchState::Panning => {
+                match self.last_touch_point {
+                    Some(p0) => {
+                        let delta = point - p0;
+                        self.on_scroll_window_event(delta, point.cast().unwrap());
+                    }
+                    None => warn!("last_touch_point not set")
+                }
+            }
+            TouchState::DefaultPrevented => {
+                // Send the event to script.
+                if let Some(result) = self.find_topmost_layer_at_point(point / self.scene.scale) {
+                    result.layer.send_event(self,
+                                            TouchMoveEvent(identifier, result.point.to_untyped()));
+                }
+            }
+        }
+        self.last_touch_point = Some(point);
+    }
+
+    fn on_touch_up(&mut self, identifier: i32, point: TypedPoint2D<DevicePixel, f32>) {
+        // TODO: Track the number of active touch points, and don't reset stuff until it is zero.
+        self.first_touch_point = None;
+        self.last_touch_point = None;
+
+        // Send the event to script.
+        if let Some(result) = self.find_topmost_layer_at_point(point / self.scene.scale) {
+            result.layer.send_event(self, TouchUpEvent(identifier, result.point.to_untyped()));
+        }
+
+        match self.touch_gesture_state {
+            TouchState::Nothing => warn!("Got unexpected touch up event"),
+
+            TouchState::WaitingForScript => {}
+            TouchState::Touching => {
+                // TODO: If the duration exceeds some threshold, send a contextmenu event instead.
+                // TODO: Don't send a click if preventDefault is called on the touchend event.
+                self.simulate_mouse_click(point);
+            }
+            TouchState::Panning => {}
+            TouchState::DefaultPrevented => {}
+        }
+        self.touch_gesture_state = TouchState::Nothing;
+    }
+
+    /// http://w3c.github.io/touch-events/#mouse-events
+    fn simulate_mouse_click(&self, p: TypedPoint2D<DevicePixel, f32>) {
+        match self.find_topmost_layer_at_point(p / self.scene.scale) {
+            Some(HitTestResult { layer, point }) => {
+                let button = MouseButton::Left;
+                layer.send_mouse_move_event(self, point);
+                layer.send_mouse_event(self, MouseWindowEvent::MouseDown(button, p), point);
+                layer.send_mouse_event(self, MouseWindowEvent::MouseUp(button, p), point);
+                layer.send_mouse_event(self, MouseWindowEvent::Click(button, p), point);
+            }
+            None => {},
+        }
+    }
+
     fn on_scroll_window_event(&mut self,
                               delta: TypedPoint2D<DevicePixel, f32>,
                               cursor: TypedPoint2D<DevicePixel, i32>) {
diff --git a/components/compositing/compositor_layer.rs b/components/compositing/compositor_layer.rs
index 811f704f52d..8e1330b9344 100644
--- a/components/compositing/compositor_layer.rs
+++ b/components/compositing/compositor_layer.rs
@@ -12,7 +12,8 @@ use layers::color::Color;
 use layers::geometry::LayerPixel;
 use layers::layers::{Layer, LayerBufferSet};
 use msg::compositor_msg::{Epoch, LayerId, LayerProperties, ScrollPolicy};
-use msg::constellation_msg::{PipelineId};
+use msg::constellation_msg::PipelineId;
+use script_traits::CompositorEvent;
 use script_traits::CompositorEvent::{ClickEvent, MouseDownEvent, MouseMoveEvent, MouseUpEvent};
 use script_traits::ConstellationControlMsg;
 use std::rc::Rc;
@@ -132,6 +133,11 @@ pub trait CompositorLayer {
                                      cursor: TypedPoint2D<LayerPixel, f32>)
                                      where Window: WindowMethods;
 
+    fn send_event<Window>(&self,
+                          compositor: &IOCompositor<Window>,
+                          event: CompositorEvent)
+                          where Window: WindowMethods;
+
     fn clamp_scroll_offset_and_scroll_layer(&self,
                                             new_offset: TypedPoint2D<LayerPixel, f32>)
                                             -> ScrollEventResult;
@@ -372,22 +378,22 @@ impl CompositorLayer for Layer<CompositorData> {
             MouseWindowEvent::MouseUp(button, _) =>
                 MouseUpEvent(button, event_point),
         };
-
-        if let Some(pipeline) = compositor.pipeline(self.pipeline_id()) {
-            pipeline.script_chan
-                    .send(ConstellationControlMsg::SendEvent(pipeline.id.clone(), message))
-                    .unwrap();
-        }
+        self.send_event(compositor, message);
     }
 
     fn send_mouse_move_event<Window>(&self,
                                      compositor: &IOCompositor<Window>,
                                      cursor: TypedPoint2D<LayerPixel, f32>)
                                      where Window: WindowMethods {
-        let message = MouseMoveEvent(cursor.to_untyped());
+        self.send_event(compositor, MouseMoveEvent(cursor.to_untyped()));
+    }
+
+    fn send_event<Window>(&self,
+                          compositor: &IOCompositor<Window>,
+                          event: CompositorEvent) where Window: WindowMethods {
         if let Some(pipeline) = compositor.pipeline(self.pipeline_id()) {
             let _ = pipeline.script_chan
-                            .send(ConstellationControlMsg::SendEvent(pipeline.id.clone(), message));
+                    .send(ConstellationControlMsg::SendEvent(pipeline.id.clone(), event));
         }
     }
 
diff --git a/components/compositing/compositor_task.rs b/components/compositing/compositor_task.rs
index cff97842653..b9d73c6b25d 100644
--- a/components/compositing/compositor_task.rs
+++ b/components/compositing/compositor_task.rs
@@ -10,7 +10,7 @@ use headless;
 use ipc_channel::ipc::{IpcReceiver, IpcSender};
 use layers::layers::{BufferRequest, LayerBufferSet};
 use layers::platform::surface::{NativeDisplay, NativeSurface};
-use msg::compositor_msg::{Epoch, FrameTreeId, LayerId, LayerProperties};
+use msg::compositor_msg::{Epoch, EventResult, FrameTreeId, LayerId, LayerProperties};
 use msg::compositor_msg::{PaintListener, ScriptToCompositorMsg};
 use msg::constellation_msg::{AnimationState, ConstellationChan, PipelineId};
 use msg::constellation_msg::{Image, Key, KeyModifiers, KeyState};
@@ -94,6 +94,10 @@ pub fn run_script_listener_thread(compositor_proxy: Box<CompositorProxy + 'stati
             ScriptToCompositorMsg::SendKeyEvent(key, key_state, key_modifiers) => {
                 compositor_proxy.send(Msg::KeyEvent(key, key_state, key_modifiers))
             }
+
+            ScriptToCompositorMsg::TouchEventProcessed(result) => {
+                compositor_proxy.send(Msg::TouchEventProcessed(result))
+            }
         }
     }
 }
@@ -189,6 +193,8 @@ pub enum Msg {
     RecompositeAfterScroll,
     /// Sends an unconsumed key event back to the compositor.
     KeyEvent(Key, KeyState, KeyModifiers),
+    /// Script has handled a touch event, and either prevented or allowed default actions.
+    TouchEventProcessed(EventResult),
     /// Changes the cursor.
     SetCursor(Cursor),
     /// Composite to a PNG file and return the Image over a passed channel.
@@ -238,6 +244,7 @@ impl Debug for Msg {
             Msg::ScrollTimeout(..) => write!(f, "ScrollTimeout"),
             Msg::RecompositeAfterScroll => write!(f, "RecompositeAfterScroll"),
             Msg::KeyEvent(..) => write!(f, "KeyEvent"),
+            Msg::TouchEventProcessed(..) => write!(f, "TouchEventProcessed"),
             Msg::SetCursor(..) => write!(f, "SetCursor"),
             Msg::CreatePng(..) => write!(f, "CreatePng"),
             Msg::PaintTaskExited(..) => write!(f, "PaintTaskExited"),
diff --git a/components/compositing/headless.rs b/components/compositing/headless.rs
index d322ef77445..1db4d7b7ad5 100644
--- a/components/compositing/headless.rs
+++ b/components/compositing/headless.rs
@@ -120,6 +120,7 @@ impl CompositorEventListener for NullCompositor {
             Msg::ChangePageTitle(..) |
             Msg::ChangePageUrl(..) |
             Msg::KeyEvent(..) |
+            Msg::TouchEventProcessed(..) |
             Msg::SetCursor(..) |
             Msg::ViewportConstrained(..) => {}
             Msg::CreatePng(..) |