Merge 2d5818f616 into e0d96163c7

components/compositing/compositor.rs

@@ -973,6 +973,11 @@ impl IOCompositor {
                     warn!("Sending response to get screen size failed ({error:?}).");
                 }
             },
+            CompositorMsg::Viewport(webview_id, viewport_description) => {
+                if let Some(webview) = self.webview_renderers.get_mut(webview_id) {
+                    webview.set_viewport_description(viewport_description);
+                }
+            },
         }
     }
 

components/compositing/tracing.rs

@@ -59,6 +59,7 @@ mod from_constellation {
                 Self::GetScreenSize(..) => target!("GetScreenSize"),
                 Self::GetAvailableScreenSize(..) => target!("GetAvailableScreenSize"),
                 Self::CollectMemoryReport(..) => target!("CollectMemoryReport"),
+                Self::Viewport(..) => target!("Viewport"),
             }
         }
     }

components/compositing/webview_renderer.rs

@@ -8,6 +8,9 @@ use std::collections::{HashMap, VecDeque};
 use std::rc::Rc;
 
 use base::id::{PipelineId, WebViewId};
+use compositing_traits::viewport_description::{
+    DEFAULT_ZOOM, MAX_ZOOM, MIN_ZOOM, ViewportDescription,
+};
 use compositing_traits::{SendableFrameTree, WebViewTrait};
 use constellation_traits::{EmbedderToConstellationMessage, ScrollState, WindowSizeType};
 use embedder_traits::{
@@ -28,10 +31,6 @@ use webrender_api::{ExternalScrollId, HitTestFlags, ScrollLocation};
 use crate::compositor::{HitTestError, PipelineDetails, ServoRenderer};
 use crate::touch::{TouchHandler, TouchMoveAction, TouchMoveAllowed, TouchSequenceState};
 
-// Default viewport constraints
-const MAX_ZOOM: f32 = 8.0;
-const MIN_ZOOM: f32 = 0.1;
-
 #[derive(Clone, Copy)]
 struct ScrollEvent {
     /// Scroll by this offset, or to Start or End
@@ -44,8 +43,10 @@ struct ScrollEvent {
 
 #[derive(Clone, Copy)]
 enum ScrollZoomEvent {
-    /// An pinch zoom event that magnifies the view by the given factor.
+    /// A pinch zoom event that magnifies the view by the given factor.
     PinchZoom(f32),
+    /// A zoom event that magnifies the view by the factor parsed from meta tag.
+    ViewportZoom(f32),
     /// A scroll event that scrolls the scroll node at the given location by the
     /// given amount.
     Scroll(ScrollEvent),
@@ -58,7 +59,7 @@ pub(crate) struct ScrollResult {
     pub offset: LayoutVector2D,
 }
 
-#[derive(PartialEq)]
+#[derive(Debug, PartialEq)]
 pub(crate) enum PinchZoomResult {
     DidPinchZoom,
     DidNotPinchZoom,
@@ -89,9 +90,6 @@ pub(crate) struct WebViewRenderer {
     pub page_zoom: Scale<f32, CSSPixel, DeviceIndependentPixel>,
     /// "Mobile-style" zoom that does not reflow the page.
     viewport_zoom: PinchZoomFactor,
-    /// Viewport zoom constraints provided by @viewport.
-    min_viewport_zoom: Option<PinchZoomFactor>,
-    max_viewport_zoom: Option<PinchZoomFactor>,
     /// The HiDPI scale factor for the `WebView` associated with this renderer. This is controlled
     /// by the embedding layer.
     hidpi_scale_factor: Scale<f32, DeviceIndependentPixel, DevicePixel>,
@@ -102,6 +100,8 @@ pub(crate) struct WebViewRenderer {
     pending_point_input_events: RefCell<VecDeque<InputEvent>>,
     /// WebRender is not ready between `SendDisplayList` and `WebRenderFrameReady` messages.
     pub webrender_frame_ready: Cell<bool>,
+    /// Viewport Description
+    viewport_description: Option<ViewportDescription>,
 }
 
 impl Drop for WebViewRenderer {
@@ -131,13 +131,12 @@ impl WebViewRenderer {
             global,
             pending_scroll_zoom_events: Default::default(),
             page_zoom: Scale::new(1.0),
-            viewport_zoom: PinchZoomFactor::new(1.0),
-            min_viewport_zoom: Some(PinchZoomFactor::new(1.0)),
-            max_viewport_zoom: None,
+            viewport_zoom: PinchZoomFactor::new(DEFAULT_ZOOM),
             hidpi_scale_factor: Scale::new(hidpi_scale_factor.0),
             animating: false,
             pending_point_input_events: Default::default(),
             webrender_frame_ready: Cell::default(),
+            viewport_description: None,
         }
     }
 
@@ -809,12 +808,15 @@ impl WebViewRenderer {
 
         // Batch up all scroll events into one, or else we'll do way too much painting.
         let mut combined_scroll_event: Option<ScrollEvent> = None;
-        let mut combined_magnification = 1.0;
+        let mut combined_magnification = self.pinch_zoom_level().get();
         for scroll_event in self.pending_scroll_zoom_events.drain(..) {
             match scroll_event {
                 ScrollZoomEvent::PinchZoom(magnification) => {
                     combined_magnification *= magnification
                 },
+                ScrollZoomEvent::ViewportZoom(magnification) => {
+                    combined_magnification = magnification
+                },
                 ScrollZoomEvent::Scroll(scroll_event_info) => {
                     let combined_event = match combined_scroll_event.as_mut() {
                         None => {
@@ -865,9 +867,7 @@ impl WebViewRenderer {
             self.send_scroll_positions_to_layout_for_pipeline(scroll_result.pipeline_id);
         }
 
-        let pinch_zoom_result = match self
-            .set_pinch_zoom_level(self.pinch_zoom_level().get() * combined_magnification)
-        {
+        let pinch_zoom_result = match self.set_pinch_zoom_level(combined_magnification) {
             true => PinchZoomResult::DidPinchZoom,
             false => PinchZoomResult::DidNotPinchZoom,
         };
@@ -941,11 +941,8 @@ impl WebViewRenderer {
     }
 
     fn set_pinch_zoom_level(&mut self, mut zoom: f32) -> bool {
-        if let Some(min) = self.min_viewport_zoom {
-            zoom = f32::max(min.get(), zoom);
-        }
-        if let Some(max) = self.max_viewport_zoom {
-            zoom = f32::min(max.get(), zoom);
+        if let Some(viewport) = self.viewport_description.as_ref() {
+            zoom = viewport.clamp_zoom(zoom);
         }
 
         let old_zoom = std::mem::replace(&mut self.viewport_zoom, PinchZoomFactor::new(zoom));
@@ -975,7 +972,12 @@ impl WebViewRenderer {
 
         // TODO: Scroll to keep the center in view?
         self.pending_scroll_zoom_events
-            .push(ScrollZoomEvent::PinchZoom(magnification));
+            .push(ScrollZoomEvent::PinchZoom(
+                self.viewport_description
+                    .clone()
+                    .unwrap_or_default()
+                    .clamp_zoom(magnification),
+            ));
     }
 
     fn send_window_size_message(&self) {
@@ -1042,6 +1044,17 @@ impl WebViewRenderer {
         let screen_geometry = self.webview.screen_geometry().unwrap_or_default();
         (screen_geometry.available_size.to_f32() / self.hidpi_scale_factor).to_i32()
     }
+
+    pub fn set_viewport_description(&mut self, viewport_description: ViewportDescription) {
+        self.pending_scroll_zoom_events
+            .push(ScrollZoomEvent::ViewportZoom(
+                self.viewport_description
+                    .clone()
+                    .unwrap_or_default()
+                    .clamp_zoom(viewport_description.initial_scale.get()),
+            ));
+        self.viewport_description = Some(viewport_description);
+    }
 }
 
 #[derive(Clone, Copy, Debug, PartialEq)]

components/script/dom/htmlmetaelement.rs

@@ -2,6 +2,10 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
+use std::str::FromStr;
+
+use compositing_traits::CompositorMsg;
+use compositing_traits::viewport_description::ViewportDescription;
 use dom_struct::dom_struct;
 use html5ever::{LocalName, Prefix, local_name, ns};
 use js::rust::HandleObject;
@@ -61,6 +65,9 @@ impl HTMLMetaElement {
             if name == "referrer" {
                 self.apply_referrer();
             }
+            if name == "viewport" {
+                self.parse_and_send_viewport_if_necessary();
+            }
         // https://html.spec.whatwg.org/multipage/#attr-meta-http-equiv
         } else if !self.HttpEquiv().is_empty() {
             // TODO: Implement additional http-equiv candidates
@@ -115,6 +122,29 @@ impl HTMLMetaElement {
         }
     }
 
+    /// <https://drafts.csswg.org/css-viewport/#parsing-algorithm>
+    fn parse_and_send_viewport_if_necessary(&self) {
+        // Skip processing if this isn't the top level frame
+        if !self.owner_window().is_top_level() {
+            return;
+        }
+        let element = self.upcast::<Element>();
+        let Some(content) = element.get_attribute(&ns!(), &local_name!("content")) else {
+            return;
+        };
+
+        if let Ok(viewport) = ViewportDescription::from_str(&content.value()) {
+            self.owner_window()
+                .compositor_api()
+                .sender()
+                .send(CompositorMsg::Viewport(
+                    self.owner_window().webview_id(),
+                    viewport,
+                ))
+                .unwrap();
+        }
+    }
+
     /// <https://html.spec.whatwg.org/multipage/#attr-meta-http-equiv-content-security-policy>
     fn apply_csp_list(&self) {
         if let Some(parent) = self.upcast::<Node>().GetParentElement() {

components/shared/compositing/lib.rs

@@ -23,6 +23,7 @@ use webrender_api::DocumentId;
 
 pub mod display_list;
 pub mod rendering_context;
+pub mod viewport_description;
 
 use std::collections::HashMap;
 use std::sync::{Arc, Mutex};
@@ -42,6 +43,8 @@ use webrender_api::{
     ImageKey, NativeFontHandle, PipelineId as WebRenderPipelineId,
 };
 
+use crate::viewport_description::ViewportDescription;
+
 /// Sends messages to the compositor.
 #[derive(Clone)]
 pub struct CompositorProxy {
@@ -176,6 +179,8 @@ pub enum CompositorMsg {
     /// Measure the current memory usage associated with the compositor.
     /// The report must be sent on the provided channel once it's complete.
     CollectMemoryReport(ReportsChan),
+    /// A top-level frame has parsed a viewport metatag and is sending the new constraints.
+    Viewport(WebViewId, ViewportDescription),
 }
 
 impl Debug for CompositorMsg {

components/shared/compositing/viewport_description.rs

@@ -0,0 +1,175 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+//! This module contains helpers for Viewport
+
+use std::collections::HashMap;
+use std::str::FromStr;
+
+use euclid::default::Scale;
+use serde::{Deserialize, Serialize};
+
+/// Default viewport constraints
+///
+/// <https://developer.mozilla.org/en-US/docs/Web/HTML/Viewport_meta_tag#initial-scale>
+pub const MIN_ZOOM: f32 = 0.1;
+/// <https://developer.mozilla.org/en-US/docs/Web/HTML/Viewport_meta_tag#initial-scale>
+pub const MAX_ZOOM: f32 = 10.0;
+/// <https://developer.mozilla.org/en-US/docs/Web/HTML/Viewport_meta_tag#initial-scale>
+pub const DEFAULT_ZOOM: f32 = 1.0;
+
+/// <https://drafts.csswg.org/css-viewport/#parsing-algorithm>
+const SEPARATORS: [char; 2] = [',', ';']; // Comma (0x2c) and Semicolon (0x3b)
+
+/// A set of viewport descriptors:
+///
+/// <https://www.w3.org/TR/css-viewport-1/#viewport-meta>
+#[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
+pub struct ViewportDescription {
+    // https://developer.mozilla.org/en-US/docs/Web/HTML/Viewport_meta_tag#width
+    // the (minimum width) size of the viewport
+    // TODO: width Needs to be implemented
+    // https://developer.mozilla.org/en-US/docs/Web/HTML/Viewport_meta_tag#width
+    // the (minimum height) size of the viewport
+    // TODO: height Needs to be implemented
+    /// <https://developer.mozilla.org/en-US/docs/Web/HTML/Viewport_meta_tag#initial-scale>
+    /// the zoom level when the page is first loaded
+    pub initial_scale: Scale<f32>,
+
+    /// <https://developer.mozilla.org/en-US/docs/Web/HTML/Viewport_meta_tag#minimum_scale>
+    /// how much zoom out is allowed on the page.
+    pub minimum_scale: Scale<f32>,
+
+    /// <https://developer.mozilla.org/en-US/docs/Web/HTML/Viewport_meta_tag#maximum_scale>
+    /// how much zoom in is allowed on the page
+    pub maximum_scale: Scale<f32>,
+
+    /// <https://developer.mozilla.org/en-US/docs/Web/HTML/Viewport_meta_tag#user_scalable>
+    /// whether zoom in and zoom out actions are allowed on the page
+    pub user_scalable: UserScalable,
+}
+
+/// The errors that the viewport parsing can generate.
+#[derive(Debug)]
+pub enum ViewportDescriptionParseError {
+    /// When viewport attribute string is empty
+    Empty,
+}
+
+/// A set of User Zoom values:
+#[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
+pub enum UserScalable {
+    /// Zoom is not allowed
+    No = 0,
+    /// Zoom is allowed
+    Yes = 1,
+}
+
+/// Parses a viewport user scalable value.
+impl TryFrom<&str> for UserScalable {
+    type Error = &'static str;
+    fn try_from(value: &str) -> Result<Self, Self::Error> {
+        match value.to_lowercase().as_str() {
+            "yes" => Ok(UserScalable::Yes),
+            "no" => Ok(UserScalable::No),
+            _ => match value.parse::<f32>() {
+                Ok(1.0) => Ok(UserScalable::Yes),
+                Ok(0.0) => Ok(UserScalable::No),
+                _ => Err("can't convert character to UserScalable"),
+            },
+        }
+    }
+}
+
+impl Default for ViewportDescription {
+    fn default() -> Self {
+        ViewportDescription {
+            initial_scale: Scale::new(DEFAULT_ZOOM),
+            minimum_scale: Scale::new(MIN_ZOOM),
+            maximum_scale: Scale::new(MAX_ZOOM),
+            user_scalable: UserScalable::Yes,
+        }
+    }
+}
+
+impl ViewportDescription {
+    /// Iterates over the key-value pairs generated from meta tag and returns a ViewportDescription
+    fn process_viewport_key_value_pairs(pairs: HashMap<String, String>) -> ViewportDescription {
+        let mut description = ViewportDescription::default();
+        for (key, value) in &pairs {
+            match key.as_str() {
+                "initial-scale" => {
+                    if let Some(zoom) = Self::parse_viewport_value_as_zoom(value) {
+                        description.initial_scale = zoom;
+                    }
+                },
+                "minimum-scale" => {
+                    if let Some(zoom) = Self::parse_viewport_value_as_zoom(value) {
+                        description.minimum_scale = zoom;
+                    }
+                },
+                "maximum-scale" => {
+                    if let Some(zoom) = Self::parse_viewport_value_as_zoom(value) {
+                        description.maximum_scale = zoom;
+                    }
+                },
+                "user-scalable" => {
+                    if let Ok(user_zoom_allowed) = value.as_str().try_into() {
+                        description.user_scalable = user_zoom_allowed;
+                    }
+                },
+                _ => (),
+            }
+        }
+        description
+    }
+
+    /// Parses a viewport zoom value.
+    fn parse_viewport_value_as_zoom(value: &str) -> Option<Scale<f32>> {
+        value
+            .to_lowercase()
+            .as_str()
+            .parse::<f32>()
+            .ok()
+            .filter(|&n| (0.0..=10.0).contains(&n))
+            .map(Scale::new)
+    }
+
+    /// Constrains a zoom value within the allowed scale range
+    pub fn clamp_zoom(&self, zoom: f32) -> f32 {
+        zoom.clamp(self.minimum_scale.get(), self.maximum_scale.get())
+    }
+}
+
+/// <https://drafts.csswg.org/css-viewport/#parsing-algorithm>
+///
+/// This implementation differs from the specified algorithm, but is equivalent because
+/// 1. It uses higher-level string operations to process string instead of character-by-character iteration.
+/// 2. Uses trim() operation to handle whitespace instead of explicitly handling throughout the parsing process.
+impl FromStr for ViewportDescription {
+    type Err = ViewportDescriptionParseError;
+    fn from_str(string: &str) -> Result<Self, Self::Err> {
+        if string.is_empty() {
+            return Err(ViewportDescriptionParseError::Empty);
+        }
+
+        // Parse key-value pairs from the content string
+        // 1. Split the content string using SEPARATORS
+        // 2. Split into key-value pair using "=" and trim whitespaces
+        // 3. Insert into HashMap
+        let parsed_values = string
+            .split(SEPARATORS)
+            .filter_map(|pair| {
+                let mut parts = pair.split('=').map(str::trim);
+                if let (Some(key), Some(value)) = (parts.next(), parts.next()) {
+                    Some((key.to_string(), value.to_string()))
+                } else {
+                    None
+                }
+            })
+            .collect::<HashMap<String, String>>();
+
+        Ok(Self::process_viewport_key_value_pairs(parsed_values))
+    }
+}