Separate `WebviewManager` from `Webview` in `compositor` and `constellation` (#36302)

Create a separate file for `WebviewManager` to improve clarity.

Testing: This change is just a refactor, so no new tests are needed.

Signed-off-by: Shubham Gupta <shubham13297@gmail.com>

7 files changed, 253 insertions, 239 deletions

diff --git a/components/compositing/compositor.rs b/components/compositing/compositor.rs
index fc9cd16ebc9..90a7bb24cd1 100644
--- a/components/compositing/compositor.rs
+++ b/components/compositing/compositor.rs
@@ -58,7 +58,8 @@ use webrender_traits::rendering_context::RenderingContext;
 use webrender_traits::{CrossProcessCompositorMessage, ImageUpdate, RendererWebView};
 
 use crate::InitialCompositorState;
-use crate::webview::{UnknownWebView, WebView, WebViewManager};
+use crate::webview::{UnknownWebView, WebView};
+use crate::webview_manager::WebViewManager;
 use crate::windowing::{self, WebRenderDebugOption, WindowMethods};
 
 #[derive(Debug, PartialEq)]
diff --git a/components/compositing/lib.rs b/components/compositing/lib.rs
index 683677d437d..78b5355b6ad 100644
--- a/components/compositing/lib.rs
+++ b/components/compositing/lib.rs
@@ -24,6 +24,7 @@ mod tracing;
 mod compositor;
 mod touch;
 pub mod webview;
+pub mod webview_manager;
 pub mod windowing;
 
 /// Data used to construct a compositor.
diff --git a/components/compositing/webview.rs b/components/compositing/webview.rs
index 58fda6d20e5..a3140425563 100644
--- a/components/compositing/webview.rs
+++ b/components/compositing/webview.rs
@@ -4,7 +4,7 @@
 
 use std::cell::RefCell;
 use std::collections::HashMap;
-use std::collections::hash_map::{Entry, Keys, Values, ValuesMut};
+use std::collections::hash_map::Keys;
 use std::rc::Rc;
 
 use base::id::{PipelineId, WebViewId};
@@ -845,240 +845,6 @@ impl WebView {
             .push(ScrollZoomEvent::PinchZoom(magnification));
     }
 }
-#[derive(Debug)]
-pub struct WebViewManager<WebView> {
-    /// Our top-level browsing contexts. In the WebRender scene, their pipelines are the children of
-    /// a single root pipeline that also applies any pinch zoom transformation.
-    webviews: HashMap<WebViewId, WebView>,
-
-    /// The order to paint them in, topmost last.
-    pub(crate) painting_order: Vec<WebViewId>,
-}
 
 #[derive(Clone, Copy, Debug, PartialEq)]
 pub struct UnknownWebView(pub WebViewId);
-
-impl<WebView> Default for WebViewManager<WebView> {
-    fn default() -> Self {
-        Self {
-            webviews: Default::default(),
-            painting_order: Default::default(),
-        }
-    }
-}
-
-impl<WebView> WebViewManager<WebView> {
-    pub fn remove(&mut self, webview_id: WebViewId) -> Result<WebView, UnknownWebView> {
-        self.painting_order.retain(|b| *b != webview_id);
-        self.webviews
-            .remove(&webview_id)
-            .ok_or(UnknownWebView(webview_id))
-    }
-
-    pub fn get(&self, webview_id: WebViewId) -> Option<&WebView> {
-        self.webviews.get(&webview_id)
-    }
-
-    pub fn get_mut(&mut self, webview_id: WebViewId) -> Option<&mut WebView> {
-        self.webviews.get_mut(&webview_id)
-    }
-
-    /// Returns true iff the painting order actually changed.
-    pub fn show(&mut self, webview_id: WebViewId) -> Result<bool, UnknownWebView> {
-        if !self.webviews.contains_key(&webview_id) {
-            return Err(UnknownWebView(webview_id));
-        }
-        if !self.painting_order.contains(&webview_id) {
-            self.painting_order.push(webview_id);
-            return Ok(true);
-        }
-        Ok(false)
-    }
-
-    /// Returns true iff the painting order actually changed.
-    pub fn hide(&mut self, webview_id: WebViewId) -> Result<bool, UnknownWebView> {
-        if !self.webviews.contains_key(&webview_id) {
-            return Err(UnknownWebView(webview_id));
-        }
-        if self.painting_order.contains(&webview_id) {
-            self.painting_order.retain(|b| *b != webview_id);
-            return Ok(true);
-        }
-        Ok(false)
-    }
-
-    /// Returns true iff the painting order actually changed.
-    pub fn hide_all(&mut self) -> bool {
-        if !self.painting_order.is_empty() {
-            self.painting_order.clear();
-            return true;
-        }
-        false
-    }
-
-    /// Returns true iff the painting order actually changed.
-    pub fn raise_to_top(&mut self, webview_id: WebViewId) -> Result<bool, UnknownWebView> {
-        if !self.webviews.contains_key(&webview_id) {
-            return Err(UnknownWebView(webview_id));
-        }
-        if self.painting_order.last() != Some(&webview_id) {
-            self.hide(webview_id)?;
-            self.show(webview_id)?;
-            return Ok(true);
-        }
-        Ok(false)
-    }
-
-    pub fn painting_order(&self) -> impl Iterator<Item = (&WebViewId, &WebView)> {
-        self.painting_order
-            .iter()
-            .flat_map(move |webview_id| self.get(*webview_id).map(|b| (webview_id, b)))
-    }
-
-    pub fn entry(&mut self, webview_id: WebViewId) -> Entry<'_, WebViewId, WebView> {
-        self.webviews.entry(webview_id)
-    }
-
-    pub fn iter(&self) -> Values<'_, WebViewId, WebView> {
-        self.webviews.values()
-    }
-
-    pub fn iter_mut(&mut self) -> ValuesMut<'_, WebViewId, WebView> {
-        self.webviews.values_mut()
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use std::num::NonZeroU32;
-
-    use base::id::{
-        BrowsingContextId, BrowsingContextIndex, PipelineNamespace, PipelineNamespaceId, WebViewId,
-    };
-
-    use crate::webview::{UnknownWebView, WebViewManager};
-
-    fn top_level_id(namespace_id: u32, index: u32) -> WebViewId {
-        WebViewId(BrowsingContextId {
-            namespace_id: PipelineNamespaceId(namespace_id),
-            index: BrowsingContextIndex(NonZeroU32::new(index).unwrap()),
-        })
-    }
-
-    fn webviews_sorted<WebView: Clone>(
-        webviews: &WebViewManager<WebView>,
-    ) -> Vec<(WebViewId, WebView)> {
-        let mut keys = webviews.webviews.keys().collect::<Vec<_>>();
-        keys.sort();
-        keys.iter()
-            .map(|&id| (*id, webviews.webviews.get(id).cloned().unwrap()))
-            .collect()
-    }
-
-    #[test]
-    fn test() {
-        PipelineNamespace::install(PipelineNamespaceId(0));
-        let mut webviews = WebViewManager::default();
-
-        // entry() adds the webview to the map, but not the painting order.
-        webviews.entry(WebViewId::new()).or_insert('a');
-        webviews.entry(WebViewId::new()).or_insert('b');
-        webviews.entry(WebViewId::new()).or_insert('c');
-        assert!(webviews.get(top_level_id(0, 1)).is_some());
-        assert!(webviews.get(top_level_id(0, 2)).is_some());
-        assert!(webviews.get(top_level_id(0, 3)).is_some());
-        assert_eq!(
-            webviews_sorted(&webviews),
-            vec![
-                (top_level_id(0, 1), 'a'),
-                (top_level_id(0, 2), 'b'),
-                (top_level_id(0, 3), 'c'),
-            ]
-        );
-        assert!(webviews.painting_order.is_empty());
-
-        // add() returns WebViewAlreadyExists if the webview id already exists.
-        webviews.entry(top_level_id(0, 3)).or_insert('d');
-        assert!(webviews.get(top_level_id(0, 3)).is_some());
-
-        // Other methods return UnknownWebView or None if the webview id doesn’t exist.
-        assert_eq!(
-            webviews.remove(top_level_id(1, 1)),
-            Err(UnknownWebView(top_level_id(1, 1)))
-        );
-        assert_eq!(webviews.get(top_level_id(1, 1)), None);
-        assert_eq!(webviews.get_mut(top_level_id(1, 1)), None);
-        assert_eq!(
-            webviews.show(top_level_id(1, 1)),
-            Err(UnknownWebView(top_level_id(1, 1)))
-        );
-        assert_eq!(
-            webviews.hide(top_level_id(1, 1)),
-            Err(UnknownWebView(top_level_id(1, 1)))
-        );
-        assert_eq!(
-            webviews.raise_to_top(top_level_id(1, 1)),
-            Err(UnknownWebView(top_level_id(1, 1)))
-        );
-
-        // For webviews not yet visible, both show() and raise_to_top() add the given webview on top.
-        assert_eq!(webviews.show(top_level_id(0, 2)), Ok(true));
-        assert_eq!(webviews.show(top_level_id(0, 2)), Ok(false));
-        assert_eq!(webviews.painting_order, vec![top_level_id(0, 2)]);
-        assert_eq!(webviews.raise_to_top(top_level_id(0, 1)), Ok(true));
-        assert_eq!(webviews.raise_to_top(top_level_id(0, 1)), Ok(false));
-        assert_eq!(
-            webviews.painting_order,
-            vec![top_level_id(0, 2), top_level_id(0, 1)]
-        );
-        assert_eq!(webviews.show(top_level_id(0, 3)), Ok(true));
-        assert_eq!(webviews.show(top_level_id(0, 3)), Ok(false));
-        assert_eq!(
-            webviews.painting_order,
-            vec![top_level_id(0, 2), top_level_id(0, 1), top_level_id(0, 3)]
-        );
-
-        // For webviews already visible, show() does nothing, while raise_to_top() makes it on top.
-        assert_eq!(webviews.show(top_level_id(0, 1)), Ok(false));
-        assert_eq!(
-            webviews.painting_order,
-            vec![top_level_id(0, 2), top_level_id(0, 1), top_level_id(0, 3)]
-        );
-        assert_eq!(webviews.raise_to_top(top_level_id(0, 1)), Ok(true));
-        assert_eq!(webviews.raise_to_top(top_level_id(0, 1)), Ok(false));
-        assert_eq!(
-            webviews.painting_order,
-            vec![top_level_id(0, 2), top_level_id(0, 3), top_level_id(0, 1)]
-        );
-
-        // hide() removes the webview from the painting order, but not the map.
-        assert_eq!(webviews.hide(top_level_id(0, 3)), Ok(true));
-        assert_eq!(webviews.hide(top_level_id(0, 3)), Ok(false));
-        assert_eq!(
-            webviews.painting_order,
-            vec![top_level_id(0, 2), top_level_id(0, 1)]
-        );
-        assert_eq!(
-            webviews_sorted(&webviews),
-            vec![
-                (top_level_id(0, 1), 'a'),
-                (top_level_id(0, 2), 'b'),
-                (top_level_id(0, 3), 'c'),
-            ]
-        );
-
-        // painting_order() returns only the visible webviews, in painting order.
-        let mut painting_order = webviews.painting_order();
-        assert_eq!(painting_order.next(), Some((&top_level_id(0, 2), &'b')));
-        assert_eq!(painting_order.next(), Some((&top_level_id(0, 1), &'a')));
-        assert_eq!(painting_order.next(), None);
-        drop(painting_order);
-
-        // remove() removes the given webview from both the map and the painting order.
-        assert!(webviews.remove(top_level_id(0, 1)).is_ok());
-        assert!(webviews.remove(top_level_id(0, 2)).is_ok());
-        assert!(webviews.remove(top_level_id(0, 3)).is_ok());
-        assert!(webviews_sorted(&webviews).is_empty());
-        assert!(webviews.painting_order.is_empty());
-    }
-}
diff --git a/components/compositing/webview_manager.rs b/components/compositing/webview_manager.rs
new file mode 100644
index 00000000000..1f1ced3a468
--- /dev/null
+++ b/components/compositing/webview_manager.rs
@@ -0,0 +1,246 @@
+/* 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/. */
+
+use std::collections::HashMap;
+use std::collections::hash_map::{Entry, Values, ValuesMut};
+
+use base::id::WebViewId;
+
+use crate::webview::UnknownWebView;
+
+#[derive(Debug)]
+pub struct WebViewManager<WebView> {
+    /// Our top-level browsing contexts. In the WebRender scene, their pipelines are the children of
+    /// a single root pipeline that also applies any pinch zoom transformation.
+    webviews: HashMap<WebViewId, WebView>,
+
+    /// The order to paint them in, topmost last.
+    pub(crate) painting_order: Vec<WebViewId>,
+}
+
+impl<WebView> Default for WebViewManager<WebView> {
+    fn default() -> Self {
+        Self {
+            webviews: Default::default(),
+            painting_order: Default::default(),
+        }
+    }
+}
+
+impl<WebView> WebViewManager<WebView> {
+    pub fn remove(&mut self, webview_id: WebViewId) -> Result<WebView, UnknownWebView> {
+        self.painting_order.retain(|b| *b != webview_id);
+        self.webviews
+            .remove(&webview_id)
+            .ok_or(UnknownWebView(webview_id))
+    }
+
+    pub fn get(&self, webview_id: WebViewId) -> Option<&WebView> {
+        self.webviews.get(&webview_id)
+    }
+
+    pub fn get_mut(&mut self, webview_id: WebViewId) -> Option<&mut WebView> {
+        self.webviews.get_mut(&webview_id)
+    }
+
+    /// Returns true iff the painting order actually changed.
+    pub fn show(&mut self, webview_id: WebViewId) -> Result<bool, UnknownWebView> {
+        if !self.webviews.contains_key(&webview_id) {
+            return Err(UnknownWebView(webview_id));
+        }
+        if !self.painting_order.contains(&webview_id) {
+            self.painting_order.push(webview_id);
+            return Ok(true);
+        }
+        Ok(false)
+    }
+
+    /// Returns true iff the painting order actually changed.
+    pub fn hide(&mut self, webview_id: WebViewId) -> Result<bool, UnknownWebView> {
+        if !self.webviews.contains_key(&webview_id) {
+            return Err(UnknownWebView(webview_id));
+        }
+        if self.painting_order.contains(&webview_id) {
+            self.painting_order.retain(|b| *b != webview_id);
+            return Ok(true);
+        }
+        Ok(false)
+    }
+
+    /// Returns true iff the painting order actually changed.
+    pub fn hide_all(&mut self) -> bool {
+        if !self.painting_order.is_empty() {
+            self.painting_order.clear();
+            return true;
+        }
+        false
+    }
+
+    /// Returns true iff the painting order actually changed.
+    pub fn raise_to_top(&mut self, webview_id: WebViewId) -> Result<bool, UnknownWebView> {
+        if !self.webviews.contains_key(&webview_id) {
+            return Err(UnknownWebView(webview_id));
+        }
+        if self.painting_order.last() != Some(&webview_id) {
+            self.hide(webview_id)?;
+            self.show(webview_id)?;
+            return Ok(true);
+        }
+        Ok(false)
+    }
+
+    pub fn painting_order(&self) -> impl Iterator<Item = (&WebViewId, &WebView)> {
+        self.painting_order
+            .iter()
+            .flat_map(move |webview_id| self.get(*webview_id).map(|b| (webview_id, b)))
+    }
+
+    pub fn entry(&mut self, webview_id: WebViewId) -> Entry<'_, WebViewId, WebView> {
+        self.webviews.entry(webview_id)
+    }
+
+    pub fn iter(&self) -> Values<'_, WebViewId, WebView> {
+        self.webviews.values()
+    }
+
+    pub fn iter_mut(&mut self) -> ValuesMut<'_, WebViewId, WebView> {
+        self.webviews.values_mut()
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use std::num::NonZeroU32;
+
+    use base::id::{
+        BrowsingContextId, BrowsingContextIndex, PipelineNamespace, PipelineNamespaceId, WebViewId,
+    };
+
+    use crate::webview::UnknownWebView;
+    use crate::webview_manager::WebViewManager;
+
+    fn top_level_id(namespace_id: u32, index: u32) -> WebViewId {
+        WebViewId(BrowsingContextId {
+            namespace_id: PipelineNamespaceId(namespace_id),
+            index: BrowsingContextIndex(NonZeroU32::new(index).unwrap()),
+        })
+    }
+
+    fn webviews_sorted<WebView: Clone>(
+        webviews: &WebViewManager<WebView>,
+    ) -> Vec<(WebViewId, WebView)> {
+        let mut keys = webviews.webviews.keys().collect::<Vec<_>>();
+        keys.sort();
+        keys.iter()
+            .map(|&id| (*id, webviews.webviews.get(id).cloned().unwrap()))
+            .collect()
+    }
+
+    #[test]
+    fn test() {
+        PipelineNamespace::install(PipelineNamespaceId(0));
+        let mut webviews = WebViewManager::default();
+
+        // entry() adds the webview to the map, but not the painting order.
+        webviews.entry(WebViewId::new()).or_insert('a');
+        webviews.entry(WebViewId::new()).or_insert('b');
+        webviews.entry(WebViewId::new()).or_insert('c');
+        assert!(webviews.get(top_level_id(0, 1)).is_some());
+        assert!(webviews.get(top_level_id(0, 2)).is_some());
+        assert!(webviews.get(top_level_id(0, 3)).is_some());
+        assert_eq!(
+            webviews_sorted(&webviews),
+            vec![
+                (top_level_id(0, 1), 'a'),
+                (top_level_id(0, 2), 'b'),
+                (top_level_id(0, 3), 'c'),
+            ]
+        );
+        assert!(webviews.painting_order.is_empty());
+
+        // add() returns WebViewAlreadyExists if the webview id already exists.
+        webviews.entry(top_level_id(0, 3)).or_insert('d');
+        assert!(webviews.get(top_level_id(0, 3)).is_some());
+
+        // Other methods return UnknownWebView or None if the webview id doesn’t exist.
+        assert_eq!(
+            webviews.remove(top_level_id(1, 1)),
+            Err(UnknownWebView(top_level_id(1, 1)))
+        );
+        assert_eq!(webviews.get(top_level_id(1, 1)), None);
+        assert_eq!(webviews.get_mut(top_level_id(1, 1)), None);
+        assert_eq!(
+            webviews.show(top_level_id(1, 1)),
+            Err(UnknownWebView(top_level_id(1, 1)))
+        );
+        assert_eq!(
+            webviews.hide(top_level_id(1, 1)),
+            Err(UnknownWebView(top_level_id(1, 1)))
+        );
+        assert_eq!(
+            webviews.raise_to_top(top_level_id(1, 1)),
+            Err(UnknownWebView(top_level_id(1, 1)))
+        );
+
+        // For webviews not yet visible, both show() and raise_to_top() add the given webview on top.
+        assert_eq!(webviews.show(top_level_id(0, 2)), Ok(true));
+        assert_eq!(webviews.show(top_level_id(0, 2)), Ok(false));
+        assert_eq!(webviews.painting_order, vec![top_level_id(0, 2)]);
+        assert_eq!(webviews.raise_to_top(top_level_id(0, 1)), Ok(true));
+        assert_eq!(webviews.raise_to_top(top_level_id(0, 1)), Ok(false));
+        assert_eq!(
+            webviews.painting_order,
+            vec![top_level_id(0, 2), top_level_id(0, 1)]
+        );
+        assert_eq!(webviews.show(top_level_id(0, 3)), Ok(true));
+        assert_eq!(webviews.show(top_level_id(0, 3)), Ok(false));
+        assert_eq!(
+            webviews.painting_order,
+            vec![top_level_id(0, 2), top_level_id(0, 1), top_level_id(0, 3)]
+        );
+
+        // For webviews already visible, show() does nothing, while raise_to_top() makes it on top.
+        assert_eq!(webviews.show(top_level_id(0, 1)), Ok(false));
+        assert_eq!(
+            webviews.painting_order,
+            vec![top_level_id(0, 2), top_level_id(0, 1), top_level_id(0, 3)]
+        );
+        assert_eq!(webviews.raise_to_top(top_level_id(0, 1)), Ok(true));
+        assert_eq!(webviews.raise_to_top(top_level_id(0, 1)), Ok(false));
+        assert_eq!(
+            webviews.painting_order,
+            vec![top_level_id(0, 2), top_level_id(0, 3), top_level_id(0, 1)]
+        );
+
+        // hide() removes the webview from the painting order, but not the map.
+        assert_eq!(webviews.hide(top_level_id(0, 3)), Ok(true));
+        assert_eq!(webviews.hide(top_level_id(0, 3)), Ok(false));
+        assert_eq!(
+            webviews.painting_order,
+            vec![top_level_id(0, 2), top_level_id(0, 1)]
+        );
+        assert_eq!(
+            webviews_sorted(&webviews),
+            vec![
+                (top_level_id(0, 1), 'a'),
+                (top_level_id(0, 2), 'b'),
+                (top_level_id(0, 3), 'c'),
+            ]
+        );
+
+        // painting_order() returns only the visible webviews, in painting order.
+        let mut painting_order = webviews.painting_order();
+        assert_eq!(painting_order.next(), Some((&top_level_id(0, 2), &'b')));
+        assert_eq!(painting_order.next(), Some((&top_level_id(0, 1), &'a')));
+        assert_eq!(painting_order.next(), None);
+        drop(painting_order);
+
+        // remove() removes the given webview from both the map and the painting order.
+        assert!(webviews.remove(top_level_id(0, 1)).is_ok());
+        assert!(webviews.remove(top_level_id(0, 2)).is_ok());
+        assert!(webviews.remove(top_level_id(0, 3)).is_ok());
+        assert!(webviews_sorted(&webviews).is_empty());
+        assert!(webviews.painting_order.is_empty());
+    }
+}
diff --git a/components/constellation/constellation.rs b/components/constellation/constellation.rs
index 3c3a9f761b0..20ff87f8a82 100644
--- a/components/constellation/constellation.rs
+++ b/components/constellation/constellation.rs
@@ -175,7 +175,7 @@ use crate::serviceworker::ServiceWorkerUnprivilegedContent;
 use crate::session_history::{
     JointSessionHistory, NeedsToReload, SessionHistoryChange, SessionHistoryDiff,
 };
-use crate::webview::WebViewManager;
+use crate::webview_manager::WebViewManager;
 
 type PendingApprovalNavigations = HashMap<PipelineId, (LoadData, NavigationHistoryBehavior)>;
 
diff --git a/components/constellation/lib.rs b/components/constellation/lib.rs
index e00bc060cd5..20f7b23af46 100644
--- a/components/constellation/lib.rs
+++ b/components/constellation/lib.rs
@@ -15,7 +15,7 @@ mod pipeline;
 mod sandboxing;
 mod serviceworker;
 mod session_history;
-mod webview;
+mod webview_manager;
 
 pub use crate::constellation::{Constellation, InitialConstellationState};
 pub use crate::logging::{FromCompositorLogger, FromScriptLogger};
diff --git a/components/constellation/webview.rs b/components/constellation/webview_manager.rs
index 8b134b62f2e..e5e427d40a1 100644
--- a/components/constellation/webview.rs
+++ b/components/constellation/webview_manager.rs
@@ -87,7 +87,7 @@ mod test {
         BrowsingContextId, BrowsingContextIndex, PipelineNamespace, PipelineNamespaceId, WebViewId,
     };
 
-    use crate::webview::WebViewManager;
+    use crate::webview_manager::WebViewManager;
 
     fn id(namespace_id: u32, index: u32) -> WebViewId {
         WebViewId(BrowsingContextId {