Merge pull request #902 from lightpanda-io/window_DOMContentLoaded

Trigger the DOMContentLoaded on the Window

src/browser/html/document.zig

@@ -278,15 +278,17 @@ pub const HTMLDocument = struct {
         const state = try page.getOrCreateNodeState(@alignCast(@ptrCast(self)));
         state.ready_state = .interactive;
 
-        const evt = try parser.eventCreate();
-        defer parser.eventDestroy(evt);
-
         log.debug(.script_event, "dispatch event", .{
             .type = "DOMContentLoaded",
             .source = "document",
         });
+
+        const evt = try parser.eventCreate();
+        defer parser.eventDestroy(evt);
         try parser.eventInit(evt, "DOMContentLoaded", .{ .bubbles = true, .cancelable = true });
         _ = try parser.eventTargetDispatchEvent(parser.toEventTarget(parser.DocumentHTML, self), evt);
+
+        try page.window.dispatchForDocumentTarget(evt);
     }
 
     pub fn documentIsComplete(self: *parser.DocumentHTML, page: *Page) !void {

src/browser/html/window.zig

@@ -334,6 +334,23 @@ pub const Window = struct {
             );
         }
     }
+
+    // libdom's document doesn't have a parent, which is correct, but
+    // breaks the event bubbling that happens for many events from
+    // document -> window.
+    // We need to force dispatch this event on the window, with the
+    // document target.
+    // In theory, we should do this for a lot of events and might need
+    // to come up with a good way to solve this more generically. But
+    // this specific event, and maybe a few others in the near future,
+    // are blockers.
+    // Worth noting that NetSurf itself appears to do something similar:
+    // https://github.com/netsurf-browser/netsurf/blob/a32e1a03e1c91ee9f0aa211937dbae7a96831149/content/handlers/html/html.c#L380
+    pub fn dispatchForDocumentTarget(self: *Window, evt: *parser.Event) !void {
+        // we assume that this evt has already been dispatched on the document
+        // and thus the target has already been set to the document.
+        return self.base.redispatchEvent(evt);
+    }
 };
 
 const TimerCallback = struct {
@@ -491,4 +508,21 @@ test "Browser.HTML.Window" {
         .{ "var qm = false; window.queueMicrotask(() => {qm = true });", null },
         .{ "qm", "true" },
     }, .{});
+
+    {
+        try runner.testCases(&.{
+            .{
+                \\ let dcl = false;
+                \\ window.addEventListener('DOMContentLoaded', (e) => {
+                \\   dcl = e.target == document;
+                \\ });
+                ,
+                null,
+            },
+        }, .{});
+        try runner.dispatchDOMContentLoaded();
+        try runner.testCases(&.{
+            .{ "dcl", "true" },
+        }, .{});
+    }
 }

src/browser/netsurf.zig

@@ -846,6 +846,14 @@ pub const EventTargetTBase = extern struct {
         internal_type_.* = @intFromEnum(self.internal_target_type);
         return c.DOM_NO_ERR;
     }
+
+    // Called to simulate bubbling from a libdom node (e.g. the Document) to a
+    // Zig instance (e.g. the Window).
+    pub fn redispatchEvent(self: *EventTargetTBase, evt: *Event) !void {
+        var res: bool = undefined;
+        const err = c._dom_event_target_dispatch(@ptrCast(self), &self.eti, evt, c.DOM_BUBBLING_PHASE, &res);
+        try DOMErr(err);
+    }
 };
 
 // MouseEvent

src/testing.zig

@@ -474,6 +474,12 @@ pub const JsRunner = struct {
             return err;
         };
     }
+
+    pub fn dispatchDOMContentLoaded(self: *JsRunner) !void {
+        const HTMLDocument = @import("browser/html/document.zig").HTMLDocument;
+        const html_doc = self.page.window.document;
+        try HTMLDocument.documentIsLoaded(html_doc, self.page);
+    }
 };
 
 const RunnerOpts = struct {