webdriver: Implement Pointer ID (#39642)

This is necessary first step to distinguish pointer sources: "mouse,
pen, touch".

Spec: https://w3c.github.io/webdriver/#dfn-get-a-pointer-id.

Testing: No behaviour change yet as we still only dispatch pointer type:
mouse.
Fixes: Part of #39264.

---------

Signed-off-by: Euclid Ye <yezhizhenjiakang@gmail.com>

components/webdriver_server/actions.rs

@@ -41,11 +41,11 @@ pub(crate) enum ActionItem {
     Wheel(WheelActionItem),
 }
 
-// A set of actions with multiple sources executed within a single tick.
-// The `id` is used to identify the source of the actions.
+/// A set of actions with multiple sources executed within a single tick.
+/// The `id` is used to identify the source of the actions.
 pub(crate) type TickActions = Vec<(String, ActionItem)>;
 
-// Consumed by the `dispatch_actions` method.
+/// Consumed by the `dispatch_actions` method.
 pub(crate) type ActionsByTick = Vec<TickActions>;
 
 /// <https://w3c.github.io/webdriver/#dfn-input-source-state>
@@ -63,19 +63,38 @@ pub(crate) enum InputSourceState {
 pub(crate) struct PointerInputState {
     subtype: PointerType,
     pressed: FxHashSet<u64>,
+    pub(crate) pointer_id: u32,
     x: f64,
     y: f64,
 }
 
 impl PointerInputState {
-    pub fn new(subtype: PointerType) -> PointerInputState {
+    /// <https://w3c.github.io/webdriver/#dfn-create-a-pointer-input-source>
+    pub(crate) fn new(subtype: PointerType, pointer_ids: FxHashSet<u32>) -> PointerInputState {
         PointerInputState {
             subtype,
             pressed: FxHashSet::default(),
+            pointer_id: Self::get_pointer_id(subtype, pointer_ids),
             x: 0.0,
             y: 0.0,
         }
     }
+
+    /// <https://w3c.github.io/webdriver/#dfn-get-a-pointer-id>
+    pub(crate) fn get_pointer_id(subtype: PointerType, pointer_ids: FxHashSet<u32>) -> u32 {
+        // Step 2 - 4: Let pointer ids be all the values in input state map which is
+        // pointer input source. This is already done and passed by the caller.
+        if subtype == PointerType::Mouse {
+            for id in 0..=1 {
+                if !pointer_ids.contains(&id) {
+                    return id;
+                }
+            }
+        }
+
+        // We are dealing with subtype other than mouse, which has minimum id 2.
+        1 + pointer_ids.into_iter().max().unwrap_or(1)
+    }
 }
 
 /// <https://w3c.github.io/webdriver/#dfn-computing-the-tick-duration>
@@ -902,13 +921,13 @@ impl Handler {
         // Step 2. Let id be the value of the id property of action sequence.
         let id = action_sequence.id.clone();
 
-        let mut input_state_table = self.session().unwrap().input_state_table_mut();
-
         match action_sequence.actions {
             ActionsType::Null {
                 actions: null_actions,
             } => {
-                input_state_table
+                self.session()
+                    .unwrap()
+                    .input_state_table_mut()
                     .entry(id)
                     .or_insert(InputSourceState::Null);
                 null_actions.into_iter().map(ActionItem::Null).collect()
@@ -916,7 +935,9 @@ impl Handler {
             ActionsType::Key {
                 actions: key_actions,
             } => {
-                input_state_table
+                self.session()
+                    .unwrap()
+                    .input_state_table_mut()
                     .entry(id)
                     .or_insert(InputSourceState::Key(KeyInputState::new()));
                 key_actions.into_iter().map(ActionItem::Key).collect()
@@ -925,10 +946,14 @@ impl Handler {
                 parameters: _,
                 actions: pointer_actions,
             } => {
-                input_state_table
+                let pointer_ids = self.session().unwrap().pointer_ids();
+                self.session()
+                    .unwrap()
+                    .input_state_table_mut()
                     .entry(id)
                     .or_insert(InputSourceState::Pointer(PointerInputState::new(
                         PointerType::Mouse,
+                        pointer_ids,
                     )));
                 pointer_actions
                     .into_iter()
@@ -938,7 +963,9 @@ impl Handler {
             ActionsType::Wheel {
                 actions: wheel_actions,
             } => {
-                input_state_table
+                self.session()
+                    .unwrap()
+                    .input_state_table_mut()
                     .entry(id)
                     .or_insert(InputSourceState::Wheel);
                 wheel_actions.into_iter().map(ActionItem::Wheel).collect()

components/webdriver_server/lib.rs

@@ -2248,14 +2248,16 @@ impl Handler {
         }
     }
 
+    /// <https://w3c.github.io/webdriver/#element-click>
+    /// Step 8 for elements other than <option>
     fn perform_element_click(&mut self, element: String) -> WebDriverResult<WebDriverResponse> {
-        // Step 8 for elements other than <option>
+        // Step 8.1 - 8.4: Create UUID, create input source "pointer".
         let id = Uuid::new_v4().to_string();
 
-        // Step 8.1
+        let pointer_ids = self.session()?.pointer_ids();
         self.session_mut()?.input_state_table_mut().insert(
             id.clone(),
-            InputSourceState::Pointer(PointerInputState::new(PointerType::Mouse)),
+            InputSourceState::Pointer(PointerInputState::new(PointerType::Mouse, pointer_ids)),
         );
 
         // Step 8.7. Construct a pointer move action.

components/webdriver_server/session.rs

@@ -6,6 +6,7 @@ use std::cell::{Ref, RefCell, RefMut};
 use std::collections::HashMap;
 
 use base::id::{BrowsingContextId, WebViewId};
+use rustc_hash::FxHashSet;
 use serde_json::{Map, Value, json};
 use uuid::Uuid;
 use webdriver::error::WebDriverResult;
@@ -129,6 +130,16 @@ impl WebDriverSession {
         self.input_state_table.borrow_mut()
     }
 
+    pub fn pointer_ids(&self) -> FxHashSet<u32> {
+        self.input_state_table()
+            .values()
+            .filter_map(|source| match source {
+                InputSourceState::Pointer(pointer_state) => Some(pointer_state.pointer_id),
+                _ => None,
+            })
+            .collect()
+    }
+
     pub fn input_cancel_list_mut(&self) -> RefMut<'_, Vec<(String, ActionItem)>> {
         self.input_cancel_list.borrow_mut()
     }