LibWeb: Implement more of the download attribute

Libraries/LibWeb/HTML/HTMLAnchorElement.cpp

@@ -122,22 +122,18 @@ void HTMLAnchorElement::activation_behavior(Web::DOM::Event const& event)
 
     // 5. If the user has expressed a preference to download the hyperlink, then set userInvolvement to "browser UI".
     // NOTE: That is, if the user has expressed a specific preference for downloading, this no longer counts as merely "activation".
-    if (has_download_preference())
+    if (has_attribute(HTML::AttributeNames::download))
         user_involvement = UserNavigationInvolvement::BrowserUI;
 
-    // FIXME: 6. If element has a download attribute, or if the user has expressed a preference to download the
+    // 6. If element has a download attribute, or if the user has expressed a preference to download the
     //     hyperlink, then download the hyperlink created by element with hyperlinkSuffix set to hyperlinkSuffix and
     //     userInvolvement set to userInvolvement.
+    download_hyperlink(hyperlink_suffix, user_involvement);
 
     // 7. Otherwise, follow the hyperlink created by element with hyperlinkSuffix set to hyperlinkSuffix and userInvolvement set to userInvolvement.
     follow_the_hyperlink(hyperlink_suffix, user_involvement);
 }
 
-bool HTMLAnchorElement::has_download_preference() const
-{
-    return has_attribute(HTML::AttributeNames::download);
-}
-
 // https://html.spec.whatwg.org/multipage/interaction.html#dom-tabindex
 i32 HTMLAnchorElement::default_tab_index_value() const
 {

Libraries/LibWeb/HTML/HTMLAnchorElement.h

@@ -43,7 +43,6 @@ private:
 
     virtual bool has_activation_behavior() const override;
     virtual void activation_behavior(Web::DOM::Event const&) override;
-    virtual bool has_download_preference() const;
 
     // ^DOM::Element
     virtual void attribute_changed(FlyString const& name, Optional<String> const& old_value, Optional<String> const& value, Optional<FlyString> const& namespace_) override;

Libraries/LibWeb/HTML/HTMLHyperlinkElementUtils.cpp

@@ -8,6 +8,9 @@
 #include <LibWeb/DOM/Document.h>
 #include <LibWeb/HTML/HTMLHyperlinkElementUtils.h>
 #include <LibWeb/HTML/Navigable.h>
+#include <LibWeb/HTML/Navigation.h>
+#include <LibWeb/HTML/Window.h>
+#include <LibWeb/Platform/EventLoopPlugin.h>
 
 namespace Web::HTML {
 
@@ -509,4 +512,54 @@ void HTMLHyperlinkElementUtils::follow_the_hyperlink(Optional<String> hyperlink_
     MUST(target_navigable->navigate({ .url = url_string, .source_document = hyperlink_element_utils_document(), .referrer_policy = referrer_policy, .user_involvement = user_involvement }));
 }
 
+void HTMLHyperlinkElementUtils::download_hyperlink(Optional<String> hyperlink_suffix, UserNavigationInvolvement user_involvement)
+{
+    // 1. If subject cannot navigate, then return.
+    if (cannot_navigate())
+        return;
+
+    // 2. If subject's node document's active sandboxing flag set has the sandboxed downloads browsing context flag set, then return.
+    if (has_flag(hyperlink_element_utils_document().active_sandboxing_flag_set(), SandboxingFlagSet::SandboxedDownloads))
+        return;
+
+    // 3. Let urlString be the result of encoding-parsing-and-serializing a URL given subject's href attribute value, relative to subject's node document.
+    auto url = hyperlink_element_utils_document().parse_url(href());
+
+    // 4. If urlString is failure, then return.
+    if (!url.is_valid())
+        return;
+
+    auto url_string = MUST(url.to_string());
+
+    // 5. If hyperlinkSuffix is non-null, then append it to urlString.
+    if (hyperlink_suffix.has_value()) {
+        StringBuilder url_builder;
+        url_builder.append(url_string);
+        url_builder.append(*hyperlink_suffix);
+
+        url_string = MUST(url_builder.to_string());
+    }
+
+    // 6. If userInvolvement is not "browser UI", then:
+    if (user_involvement != UserNavigationInvolvement::BrowserUI) {
+        // 1. Assert: subject has a download attribute.
+        VERIFY(hyperlink_element_utils_element().has_attribute(HTML::AttributeNames::download));
+
+        // 2. Let navigation be subject's relevant global object's navigation API.
+        auto navigation = verify_cast<Window>(relevant_global_object(hyperlink_element_utils_element())).navigation();
+
+        // 3. Let filename be the value of subject's download attribute.
+        auto filename = hyperlink_element_utils_element().attribute(HTML::AttributeNames::download).value_or(String {});
+
+        // 4. Let continue be the result of firing a download request navigate event at navigation with destinationURL set to urlString, userInvolvement set to userInvolvement, and filename set to filename.
+        bool continue_ = navigation->fire_a_download_request_navigate_event(url_string, user_involvement, filename);
+
+        // 5. If continue is false, then return.
+        if (!continue_)
+            return;
+    }
+
+    // FIXME: 7. Run these steps in parallel:
+}
+
 }

Libraries/LibWeb/HTML/HTMLHyperlinkElementUtils.h

@@ -65,6 +65,7 @@ protected:
 
     void set_the_url();
     void follow_the_hyperlink(Optional<String> hyperlink_suffix, UserNavigationInvolvement = UserNavigationInvolvement::None);
+    void download_hyperlink(Optional<String> hyperlink_suffix, UserNavigationInvolvement = UserNavigationInvolvement::None);
 
 private:
     void reinitialize_url() const;