1 files changed, 48 insertions, 0 deletions
diff --git a/components/script/dom/htmlelement.rs b/components/script/dom/htmlelement.rs
index ac0f99416c2..00d7a64ed32 100644
--- a/components/script/dom/htmlelement.rs
+++ b/components/script/dom/htmlelement.rs
@@ -27,6 +27,7 @@ use crate::dom::htmlframesetelement::HTMLFrameSetElement;
 use crate::dom::htmlhtmlelement::HTMLHtmlElement;
 use crate::dom::htmlinputelement::{HTMLInputElement, InputType};
 use crate::dom::htmllabelelement::HTMLLabelElement;
+use crate::dom::htmltextareaelement::HTMLTextAreaElement;
 use crate::dom::node::{document_from_node, window_from_node};
 use crate::dom::node::{BindContext, Node, NodeFlags, ShadowIncluding};
 use crate::dom::text::Text;
@@ -170,6 +171,11 @@ impl HTMLElementMethods for HTMLElement {
     // https://html.spec.whatwg.org/multipage/#dom-hidden
     make_bool_setter!(SetHidden, "hidden");
 
+    // https://html.spec.whatwg.org/multipage/#the-dir-attribute
+    make_getter!(Dir, "dir");
+    // https://html.spec.whatwg.org/multipage/#the-dir-attribute
+    make_setter!(SetDir, "dir");
+
     // https://html.spec.whatwg.org/multipage/#globaleventhandlers
     global_event_handlers!(NoOnload);
 
@@ -767,6 +773,48 @@ impl HTMLElement {
             })
             .count() as u32
     }
+
+    // https://html.spec.whatwg.org/multipage/#the-directionality.
+    // returns Some if can infer direction by itself or from child nodes
+    // returns None if requires to go up to parent
+    pub fn directionality(&self) -> Option<String> {
+        let element_direction: &str = &self.Dir();
+
+        if element_direction == "ltr" {
+            return Some("ltr".to_owned());
+        }
+
+        if element_direction == "rtl" {
+            return Some("rtl".to_owned());
+        }
+
+        if let Some(input) = self.downcast::<HTMLInputElement>() {
+            if input.input_type() == InputType::Tel {
+                return Some("ltr".to_owned());
+            }
+        }
+
+        if element_direction == "auto" {
+            if let Some(directionality) = self
+                .downcast::<HTMLInputElement>()
+                .and_then(|input| input.auto_directionality())
+            {
+                return Some(directionality);
+            }
+
+            if let Some(area) = self.downcast::<HTMLTextAreaElement>() {
+                return Some(area.auto_directionality());
+            }
+        }
+
+        // TODO(NeverHappened): Implement condition
+        // If the element's dir attribute is in the auto state OR
+        // If the element is a bdi element and the dir attribute is not in a defined state
+        // (i.e. it is not present or has an invalid value)
+        // Requires bdi element implementation (https://html.spec.whatwg.org/multipage/#the-bdi-element)
+
+        None
+    }
 }
 
 impl VirtualMethods for HTMLElement {