feat(script): register import map (#37504)

- Register import map when preparing HTML script element
- Added `import_map` to `GlobalScope`

Testing: should pass existing WPT
Fixes: part of https://github.com/servo/servo/issues/37316

---------

Signed-off-by: Jason Tsai <git@pews.dev>

components/script/dom/globalscope.rs

@@ -143,7 +143,9 @@ use crate::messaging::{CommonScriptMsg, ScriptEventLoopReceiver, ScriptEventLoop
 use crate::microtask::{Microtask, MicrotaskQueue, UserMicrotask};
 use crate::network_listener::{NetworkListener, PreInvoke};
 use crate::realms::{AlreadyInRealm, InRealm, enter_realm};
-use crate::script_module::{DynamicModuleList, ModuleScript, ModuleTree, ScriptFetchOptions};
+use crate::script_module::{
+    DynamicModuleList, ImportMap, ModuleScript, ModuleTree, ScriptFetchOptions,
+};
 use crate::script_runtime::{CanGc, JSContext as SafeJSContext, ThreadSafeJSContext};
 use crate::script_thread::{ScriptThread, with_script_thread};
 use crate::security_manager::CSPViolationReportTask;
@@ -380,6 +382,12 @@ pub(crate) struct GlobalScope {
     #[ignore_malloc_size_of = "Rc<T> is hard"]
     notification_permission_request_callback_map:
         DomRefCell<HashMap<String, Rc<NotificationPermissionCallback>>>,
+
+    /// An import map allows control over module specifier resolution.
+    /// For now, only Window global objects have their import map modified from the initial empty one.
+    ///
+    /// <https://html.spec.whatwg.org/multipage/#import-maps>
+    import_map: DomRefCell<ImportMap>,
 }
 
 /// A wrapper for glue-code between the ipc router and the event-loop.
@@ -781,6 +789,7 @@ impl GlobalScope {
             byte_length_queuing_strategy_size_function: OnceCell::new(),
             count_queuing_strategy_size_function: OnceCell::new(),
             notification_permission_request_callback_map: Default::default(),
+            import_map: Default::default(),
         }
     }
 
@@ -3759,6 +3768,10 @@ impl GlobalScope {
                 .queue(task);
         }
     }
+
+    pub(crate) fn import_map(&self) -> &DomRefCell<ImportMap> {
+        &self.import_map
+    }
 }
 
 /// Returns the Rust global scope from a JS global object.

components/script/dom/htmlscriptelement.rs

@@ -49,7 +49,7 @@ use crate::dom::bindings::codegen::GenericBindings::HTMLElementBinding::HTMLElem
 use crate::dom::bindings::codegen::UnionTypes::{
     TrustedScriptOrString, TrustedScriptURLOrUSVString,
 };
-use crate::dom::bindings::error::Fallible;
+use crate::dom::bindings::error::{Error, Fallible};
 use crate::dom::bindings::inheritance::Castable;
 use crate::dom::bindings::refcounted::Trusted;
 use crate::dom::bindings::reflector::DomGlobal;
@@ -76,8 +76,8 @@ use crate::fetch::create_a_potential_cors_request;
 use crate::network_listener::{self, NetworkListener, PreInvoke, ResourceTimingListener};
 use crate::realms::enter_realm;
 use crate::script_module::{
-    ModuleOwner, ScriptFetchOptions, fetch_external_module_script, fetch_inline_module_script,
-    parse_an_import_map_string,
+    ImportMap, ModuleOwner, ScriptFetchOptions, fetch_external_module_script,
+    fetch_inline_module_script, parse_an_import_map_string, register_import_map,
 };
 use crate::script_runtime::CanGc;
 use crate::task_source::{SendableTaskSource, TaskSourceName};
@@ -308,6 +308,7 @@ pub(crate) struct ScriptOrigin {
     fetch_options: ScriptFetchOptions,
     type_: ScriptType,
     unminified_dir: Option<String>,
+    import_map: Fallible<ImportMap>,
 }
 
 impl ScriptOrigin {
@@ -317,6 +318,7 @@ impl ScriptOrigin {
         fetch_options: ScriptFetchOptions,
         type_: ScriptType,
         unminified_dir: Option<String>,
+        import_map: Fallible<ImportMap>,
     ) -> ScriptOrigin {
         ScriptOrigin {
             code: SourceCode::Text(text),
@@ -325,6 +327,7 @@ impl ScriptOrigin {
             fetch_options,
             type_,
             unminified_dir,
+            import_map,
         }
     }
 
@@ -342,6 +345,7 @@ impl ScriptOrigin {
             fetch_options,
             type_,
             unminified_dir,
+            import_map: Err(Error::NotFound),
         }
     }
 
@@ -960,11 +964,12 @@ impl HTMLScriptElement {
             match script_type {
                 ScriptType::Classic => {
                     let result = Ok(ScriptOrigin::internal(
-                        Rc::clone(&text_rc),
-                        base_url.clone(),
-                        options.clone(),
+                        text_rc,
+                        base_url,
+                        options,
                         script_type,
                         self.global().unminified_js_dir(),
+                        Err(Error::NotFound),
                     ));
 
                     if was_parser_inserted &&
@@ -1003,12 +1008,23 @@ impl HTMLScriptElement {
                 ScriptType::ImportMap => {
                     // Step 32.1 Let result be the result of creating an import map
                     // parse result given source text and base URL.
-                    let _result = parse_an_import_map_string(
+                    let import_map_result = parse_an_import_map_string(
                         ModuleOwner::Window(Trusted::new(self)),
-                        text_rc,
+                        Rc::clone(&text_rc),
                         base_url.clone(),
                         can_gc,
                     );
+                    let result = Ok(ScriptOrigin::internal(
+                        text_rc,
+                        base_url,
+                        options,
+                        script_type,
+                        self.global().unminified_js_dir(),
+                        import_map_result,
+                    ));
+
+                    // Step 34.3
+                    self.execute(result, can_gc);
                 },
             }
         }
@@ -1125,8 +1141,8 @@ impl HTMLScriptElement {
                 self.run_a_module_script(&script, false, can_gc);
             },
             ScriptType::ImportMap => {
-                // TODO: Register an import map given el's relevant
-                // global object and el's result.
+                // Step 6.1 Register an import map given el's relevant global object and el's result.
+                register_import_map(&self.owner_global(), script.import_map, can_gc);
             },
         }