Bug 1768922 - Support ESM loaded by shim in Cu.isModuleLoaded. r=yulia

Differential Revision: https://phabricator.services.mozilla.com/D146166

js/loader/ModuleLoaderBase.cpp

@@ -344,15 +344,17 @@ nsresult ModuleLoaderBase::StartOrRestartModuleLoad(ModuleLoadRequest* aRequest,
 }
 
 bool ModuleLoaderBase::ModuleMapContainsURL(nsIURI* aURL) const {
-  // Returns whether we have fetched, or are currently fetching, a module script
-  // for a URL.
-  return mFetchingModules.Contains(aURL) || mFetchedModules.Contains(aURL);
+  return IsModuleFetching(aURL) || IsModuleFetched(aURL);
 }
 
 bool ModuleLoaderBase::IsModuleFetching(nsIURI* aURL) const {
   return mFetchingModules.Contains(aURL);
 }
 
+bool ModuleLoaderBase::IsModuleFetched(nsIURI* aURL) const {
+  return mFetchedModules.Contains(aURL);
+}
+
 void ModuleLoaderBase::SetModuleFetchStarted(ModuleLoadRequest* aRequest) {
   // Update the module map to indicate that a module is currently being fetched.
 

js/loader/ModuleLoaderBase.h

@@ -16,8 +16,8 @@
 #include "nsRefPtrHashtable.h"
 #include "nsCOMArray.h"
 #include "nsCOMPtr.h"
-#include "nsILoadInfo.h"  // nsSecurityFlags
-#include "nsINode.h"      // nsIURI
+#include "nsILoadInfo.h"    // nsSecurityFlags
+#include "nsINode.h"        // nsIURI
 #include "nsThreadUtils.h"  // GetMainThreadSerialEventTarget
 #include "nsURIHashKey.h"
 #include "mozilla/CORSMode.h"
@@ -274,6 +274,9 @@ class ModuleLoaderBase : public nsISupports {
     mAcquiringImportMaps = acquiring;
   }
 
+  // Returns true if the module for given URL is already fetched.
+  bool IsModuleFetched(nsIURI* aURL) const;
+
   // Internal methods.
 
  private:

js/xpconnect/loader/mozJSComponentLoader.cpp

@@ -1100,14 +1100,27 @@ nsresult mozJSComponentLoader::IsModuleLoaded(const nsACString& aLocation,
 
   mInitialized = true;
   ComponentLoaderInfo info(aLocation);
-  *retval = !!mImports.Get(info.Key());
-
-  if (!*retval && IsJSM(aLocation)) {
-    nsAutoCString mjsLocation;
-    ToMJS(aLocation, mjsLocation);
-    return IsModuleLoaded(mjsLocation, retval);
+  if (mImports.Get(info.Key())) {
+    *retval = true;
+    return NS_OK;
   }
 
+  if (IsJSM(aLocation) && mModuleLoader) {
+    nsAutoCString mjsLocation;
+    ToMJS(aLocation, mjsLocation);
+
+    ComponentLoaderInfo mjsInfo(mjsLocation);
+
+    nsresult rv = mjsInfo.EnsureURI();
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    if (mModuleLoader->IsModuleFetched(mjsInfo.URI())) {
+      *retval = true;
+      return NS_OK;
+    }
+  }
+
+  *retval = false;
   return NS_OK;
 }
 

js/xpconnect/tests/unit/esmified-5.mjs

@@ -0,0 +1,4 @@
+export let loadCount = 0;
+loadCount++;
+
+export const obj = { value: 10 };

js/xpconnect/tests/unit/esmified-6.mjs

@@ -0,0 +1,4 @@
+export let loadCount = 0;
+loadCount++;
+
+export const obj = { value: 10 };

js/xpconnect/tests/unit/test_import_shim.js

@@ -300,3 +300,32 @@ add_task(function test_Cu_import_not_exported_shim() {
   Assert.equal(global["*namespace*"], undefined,
                `*namespace* special binding should not be exposed`);
 });
+
+add_task(function test_Cu_isModuleLoaded_shim() {
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-5.jsm"), false);
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-5.mjs"), false);
+
+  Cu.import("resource://test/esmified-5.jsm", {});
+
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-5.jsm"), true);
+
+  // This is false because Cu.isModuleLoaded does not support ESM directly
+  // (bug 1768819)
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-5.mjs"), false);
+});
+
+add_task(function test_Cu_isModuleLoaded_no_shim() {
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-6.jsm"), false);
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-6.mjs"), false);
+
+  ChromeUtils.importModule("resource://test/esmified-6.mjs");
+
+  // Regardless of whether the ESM is loaded by shim or not,
+  // query that accesses the ESM-ified module returns the existence of
+  // ESM.
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-6.jsm"), true);
+
+  // This is false because Cu.isModuleLoaded does not support ESM directly
+  // (bug 1768819)
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-6.mjs"), false);
+});

js/xpconnect/tests/unit/xpcshell.ini

@@ -32,6 +32,8 @@ support-files =
   esmified-2.mjs
   esmified-3.mjs
   esmified-4.mjs
+  esmified-5.mjs
+  esmified-6.mjs
   esmified-not-exported.mjs
   not-esmified-not-exported.jsm