dom: implement getElementsByClassName

src/dom/document.zig

@@ -54,6 +54,11 @@ pub const Document = struct {
         const root = parser.documentGetDocumentElement(self);
         return collection.HTMLCollectionByTagName(parser.elementToNode(root), tag_name);
     }
+
+    pub fn _getElementsByClassName(self: *parser.Document, classNames: []const u8) !collection.HTMLCollection {
+        const root = parser.documentGetDocumentElement(self);
+        return collection.HTMLCollectionByClassName(parser.elementToNode(root), classNames);
+    }
 };
 
 // Tests

src/dom/html_collection.zig

@@ -13,6 +13,7 @@ const Union = @import("element.zig").Union;
 
 const Match = union(enum) {
     matchByTagName: MatchByTagName,
+    matchByClassName: MatchByClassName,
 
     pub fn match(self: Match, node: *parser.Node) bool {
         switch (self) {
@@ -55,6 +56,37 @@ pub fn HTMLCollectionByTagName(root: *parser.Node, tag_name: []const u8) !HTMLCo
     };
 }
 
+pub const MatchByClassName = struct {
+    classNames: []const u8,
+
+    fn init(classNames: []const u8) !MatchByClassName {
+        return MatchByClassName{
+            .classNames = classNames,
+        };
+    }
+
+    pub fn match(self: MatchByClassName, node: *parser.Node) bool {
+        var it = std.mem.splitAny(u8, self.classNames, " ");
+        const e = parser.nodeToElement(node);
+        while (it.next()) |c| {
+            if (!parser.elementHasClass(e, c)) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+};
+
+pub fn HTMLCollectionByClassName(root: *parser.Node, classNames: []const u8) !HTMLCollection {
+    return HTMLCollection{
+        .root = root,
+        .match = Match{
+            .matchByClassName = try MatchByClassName.init(classNames),
+        },
+    };
+}
+
 // WEB IDL https://dom.spec.whatwg.org/#htmlcollection
 // HTMLCollection is re implemented in zig here because libdom
 // dom_html_collection expects a comparison function callback as arguement.

src/netsurf.zig

@@ -522,6 +522,11 @@ pub fn nodeReplaceChild(node: *Node, new_child: *Node, old_child: *Node) *Node {
     return res.?;
 }
 
+// nodeToElement is an helper to convert a node to an element.
+pub inline fn nodeToElement(node: *Node) *Element {
+    return @as(*Element, @ptrCast(node));
+}
+
 // CharacterData
 pub const CharacterData = c.dom_characterdata;
 
@@ -621,6 +626,12 @@ pub fn elementGetAttribute(elem: *Element, name: []const u8) ?[]const u8 {
     return stringToData(s.?);
 }
 
+pub fn elementHasClass(elem: *Element, class: []const u8) bool {
+    var res: bool = undefined;
+    _ = elementVtable(elem).dom_element_has_class.?(elem, stringFromData(class), &res);
+    return res;
+}
+
 // elementToNode is an helper to convert an element to a node.
 pub inline fn elementToNode(e: *Element) *Node {
     return @as(*Node, @ptrCast(e));