script: Create structures for TextTrack API

Fill out the basics for the WebIDLs for the following:

  - TextTrack
  - TextTrackCue
  - TextTrackCueList
  - TextTrackList

components/script/dom/texttrackcuelist.rs

@@ -0,0 +1,91 @@
+/* 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 crate::dom::bindings::cell::DomRefCell;
+use crate::dom::bindings::codegen::Bindings::TextTrackCueListBinding::{
+    self, TextTrackCueListMethods,
+};
+use crate::dom::bindings::reflector::{reflect_dom_object, Reflector};
+use crate::dom::bindings::root::{Dom, DomRoot};
+use crate::dom::bindings::str::DOMString;
+use crate::dom::texttrackcue::TextTrackCue;
+use crate::dom::window::Window;
+use dom_struct::dom_struct;
+
+#[dom_struct]
+pub struct TextTrackCueList {
+    reflector_: Reflector,
+    dom_cues: DomRefCell<Vec<Dom<TextTrackCue>>>,
+}
+
+impl TextTrackCueList {
+    pub fn new_inherited(cues: &[&TextTrackCue]) -> TextTrackCueList {
+        TextTrackCueList {
+            reflector_: Reflector::new(),
+            dom_cues: DomRefCell::new(cues.iter().map(|g| Dom::from_ref(&**g)).collect()),
+        }
+    }
+
+    pub fn new(window: &Window, cues: &[&TextTrackCue]) -> DomRoot<TextTrackCueList> {
+        reflect_dom_object(
+            Box::new(TextTrackCueList::new_inherited(cues)),
+            window,
+            TextTrackCueListBinding::Wrap,
+        )
+    }
+
+    pub fn item(&self, idx: usize) -> Option<DomRoot<TextTrackCue>> {
+        self.dom_cues
+            .borrow()
+            .get(idx)
+            .map(|t| DomRoot::from_ref(&**t))
+    }
+
+    pub fn find(&self, cue: &TextTrackCue) -> Option<usize> {
+        self.dom_cues
+            .borrow()
+            .iter()
+            .enumerate()
+            .filter(|(_, c)| **c == cue)
+            .next()
+            .map(|(i, _)| i)
+    }
+
+    pub fn add(&self, cue: &TextTrackCue) {
+        // Only add a cue if it does not exist in the list
+        if self.find(cue).is_none() {
+            self.dom_cues.borrow_mut().push(Dom::from_ref(cue));
+        }
+    }
+
+    pub fn remove(&self, idx: usize) {
+        self.dom_cues.borrow_mut().remove(idx);
+    }
+}
+
+impl TextTrackCueListMethods for TextTrackCueList {
+    // https://html.spec.whatwg.org/multipage/#dom-texttrackcuelist-length
+    fn Length(&self) -> u32 {
+        self.dom_cues.borrow().len() as u32
+    }
+
+    // https://html.spec.whatwg.org/multipage/#dom-texttrackcuelist-item
+    fn IndexedGetter(&self, idx: u32) -> Option<DomRoot<TextTrackCue>> {
+        self.item(idx as usize)
+    }
+
+    // https://html.spec.whatwg.org/multipage/#dom-texttrackcuelist-getcuebyid
+    fn GetCueById(&self, id: DOMString) -> Option<DomRoot<TextTrackCue>> {
+        if id.is_empty() {
+            None
+        } else {
+            self.dom_cues
+                .borrow()
+                .iter()
+                .filter(|cue| cue.id() == id)
+                .next()
+                .map(|t| DomRoot::from_ref(&**t))
+        }
+    }
+}