Bug 1437956 - Pretty print XML with Shadow DOM r=smaug

This patch puts the transformed pretty print DOM into a Shadow DOM.
The stylesheet is loaded with an @import in a <style> block, so the
monospace stylesheet had to be left out.

The XBL binding is kept, pending removal when Shadow DOM ships.
It's still needed to handle the case when Shadow DOM is pref'd off too.

MozReview-Commit-ID: DQRsXB8tumF

--HG--
extra : rebase_source : 6edc3d82392af4d98de454a5228328379a0fb7ee

dom/base/Element.cpp

@@ -1224,6 +1224,16 @@ Element::AttachShadow(const ShadowRootInit& aInit, ErrorResult& aError)
     return nullptr;
   }
 
+  if (StaticPrefs::dom_webcomponents_shadowdom_report_usage()) {
+    OwnerDoc()->ReportShadowDOMUsage();
+  }
+
+  return AttachShadowWithoutNameChecks(aInit.mMode);
+}
+
+already_AddRefed<ShadowRoot>
+Element::AttachShadowWithoutNameChecks(ShadowRootMode aMode)
+{
   nsAutoScriptBlocker scriptBlocker;
 
   RefPtr<mozilla::dom::NodeInfo> nodeInfo =
@@ -1244,14 +1254,10 @@ Element::AttachShadow(const ShadowRootInit& aInit, ErrorResult& aError)
    *    and mode is init’s mode.
    */
   RefPtr<ShadowRoot> shadowRoot =
-    new ShadowRoot(this, aInit.mMode, nodeInfo.forget());
+    new ShadowRoot(this, aMode, nodeInfo.forget());
 
   shadowRoot->SetIsComposedDocParticipant(IsInComposedDoc());
 
-  if (StaticPrefs::dom_webcomponents_shadowdom_report_usage()) {
-    OwnerDoc()->ReportShadowDOMUsage();
-  }
-
   /**
    * 5. Set context object’s shadow root to shadow.
    */
@@ -1263,6 +1269,27 @@ Element::AttachShadow(const ShadowRootInit& aInit, ErrorResult& aError)
   return shadowRoot.forget();
 }
 
+void
+Element::UnattachShadow()
+{
+  if (!GetShadowRoot()) {
+    return;
+  }
+
+  nsAutoScriptBlocker scriptBlocker;
+
+  if (nsIDocument* doc = GetComposedDoc()) {
+    if (nsIPresShell* shell = doc->GetShell()) {
+      shell->DestroyFramesForAndRestyle(this);
+    }
+  }
+  MOZ_ASSERT(!GetPrimaryFrame());
+
+  // Simply unhook the shadow root from the element.
+  MOZ_ASSERT(!GetShadowRoot()->HasSlots(), "Won't work when shadow root has slots!");
+  SetShadowRoot(nullptr);
+}
+
 void
 Element::GetAttribute(const nsAString& aName, DOMString& aReturn)
 {

dom/base/Element.h

@@ -1263,6 +1263,10 @@ public:
   // Shadow DOM v1
   already_AddRefed<ShadowRoot> AttachShadow(const ShadowRootInit& aInit,
                                             ErrorResult& aError);
+
+  already_AddRefed<ShadowRoot> AttachShadowWithoutNameChecks(ShadowRootMode aMode);
+  void UnattachShadow();
+
   ShadowRoot* GetShadowRootByMode() const;
   void SetSlot(const nsAString& aName, ErrorResult& aError);
   void GetSlot(nsAString& aName);

dom/base/ShadowRoot.h

@@ -139,6 +139,7 @@ private:
 public:
   void AddSlot(HTMLSlotElement* aSlot);
   void RemoveSlot(HTMLSlotElement* aSlot);
+  bool HasSlots() const { return !mSlotMap.IsEmpty(); };
 
   const RawServoAuthorStyles* ServoStyles() const
   {

dom/xml/nsXMLPrettyPrinter.cpp

@@ -124,68 +124,80 @@ nsXMLPrettyPrinter::PrettyPrint(nsIDocument* aDocument,
         return err.StealNSResult();
     }
 
-    //
-    // Apply the prettprint XBL binding.
-    //
-    // We take some shortcuts here. In particular, we don't bother invoking the
-    // contstructor (since the binding has no constructor), and we don't bother
-    // calling LoadBindingDocument because it's a chrome:// URI and thus will get
-    // sync loaded no matter what.
-    //
-
-    // Grab the XBL service.
-    nsXBLService* xblService = nsXBLService::GetInstance();
-    NS_ENSURE_TRUE(xblService, NS_ERROR_NOT_AVAILABLE);
-
-    // Compute the binding URI.
-    nsCOMPtr<nsIURI> bindingUri;
-    rv = NS_NewURI(getter_AddRefs(bindingUri),
-        NS_LITERAL_STRING("chrome://global/content/xml/XMLPrettyPrint.xml#prettyprint"));
-    NS_ENSURE_SUCCESS(rv, rv);
-
-    // Compute the bound element.
+    // Find the root element
     RefPtr<Element> rootElement = aDocument->GetRootElement();
     NS_ENSURE_TRUE(rootElement, NS_ERROR_UNEXPECTED);
 
-    // Grab the system principal.
-    nsCOMPtr<nsIPrincipal> sysPrincipal;
-    nsContentUtils::GetSecurityManager()->
-        GetSystemPrincipal(getter_AddRefs(sysPrincipal));
+    if (nsContentUtils::IsShadowDOMEnabled()) {
+        // Attach a closed shadow root on it.
+        RefPtr<ShadowRoot> shadowRoot =
+            rootElement->AttachShadowWithoutNameChecks(ShadowRootMode::Closed);
 
-    // Destroy any existing frames before we unbind anonymous content.
-    // Note that the shell might be Destroy'ed by now (see bug 1415541).
-    if (!shell->IsDestroying()) {
-        shell->DestroyFramesForAndRestyle(rootElement);
-    }
+        // Append the document fragment to the shadow dom.
+        shadowRoot->AppendChild(*resultFragment, err);
+        if (NS_WARN_IF(err.Failed())) {
+            return err.StealNSResult();
+        }
+    } else {
+        //
+        // Apply the prettprint XBL binding.
+        //
+        // We take some shortcuts here. In particular, we don't bother invoking the
+        // contstructor (since the binding has no constructor), and we don't bother
+        // calling LoadBindingDocument because it's a chrome:// URI and thus will get
+        // sync loaded no matter what.
+        //
 
-    // Load the bindings.
-    RefPtr<nsXBLBinding> unused;
-    bool ignored;
-    rv = xblService->LoadBindings(rootElement, bindingUri, sysPrincipal,
-                                  getter_AddRefs(unused), &ignored);
-    NS_ENSURE_SUCCESS(rv, rv);
+        // Grab the XBL service.
+        nsXBLService* xblService = nsXBLService::GetInstance();
+        NS_ENSURE_TRUE(xblService, NS_ERROR_NOT_AVAILABLE);
 
-    // Fire an event at the bound element to pass it |resultFragment|.
-    RefPtr<CustomEvent> event =
-      NS_NewDOMCustomEvent(rootElement, nullptr, nullptr);
-    MOZ_ASSERT(event);
-    AutoJSAPI jsapi;
-    if (!jsapi.Init(event->GetParentObject())) {
-        return NS_ERROR_UNEXPECTED;
-    }
-    JSContext* cx = jsapi.cx();
-    JS::Rooted<JS::Value> detail(cx);
-    if (!ToJSValue(cx, resultFragment, &detail)) {
-        return NS_ERROR_UNEXPECTED;
-    }
-    event->InitCustomEvent(cx, NS_LITERAL_STRING("prettyprint-dom-created"),
-                           /* bubbles = */ false, /* cancelable = */ false,
-                           detail);
+        // Compute the binding URI.
+        nsCOMPtr<nsIURI> bindingUri;
+        rv = NS_NewURI(getter_AddRefs(bindingUri),
+            NS_LITERAL_STRING("chrome://global/content/xml/XMLPrettyPrint.xml#prettyprint"));
+        NS_ENSURE_SUCCESS(rv, rv);
 
-    event->SetTrusted(true);
-    rootElement->DispatchEvent(*event, err);
-    if (NS_WARN_IF(err.Failed())) {
-        return err.StealNSResult();
+        // Grab the system principal.
+        nsCOMPtr<nsIPrincipal> sysPrincipal;
+        nsContentUtils::GetSecurityManager()->
+            GetSystemPrincipal(getter_AddRefs(sysPrincipal));
+
+        // Destroy any existing frames before we unbind anonymous content.
+        // Note that the shell might be Destroy'ed by now (see bug 1415541).
+        if (!shell->IsDestroying()) {
+            shell->DestroyFramesForAndRestyle(rootElement);
+        }
+
+        // Load the bindings.
+        RefPtr<nsXBLBinding> unused;
+        bool ignored;
+        rv = xblService->LoadBindings(rootElement, bindingUri, sysPrincipal,
+                                      getter_AddRefs(unused), &ignored);
+        NS_ENSURE_SUCCESS(rv, rv);
+
+        // Fire an event at the bound element to pass it |resultFragment|.
+        RefPtr<CustomEvent> event =
+          NS_NewDOMCustomEvent(rootElement, nullptr, nullptr);
+        MOZ_ASSERT(event);
+        AutoJSAPI jsapi;
+        if (!jsapi.Init(event->GetParentObject())) {
+            return NS_ERROR_UNEXPECTED;
+        }
+        JSContext* cx = jsapi.cx();
+        JS::Rooted<JS::Value> detail(cx);
+        if (!ToJSValue(cx, resultFragment, &detail)) {
+            return NS_ERROR_UNEXPECTED;
+        }
+        event->InitCustomEvent(cx, NS_LITERAL_STRING("prettyprint-dom-created"),
+                               /* bubbles = */ false, /* cancelable = */ false,
+                               detail);
+
+        event->SetTrusted(true);
+        rootElement->DispatchEvent(*event, err);
+        if (NS_WARN_IF(err.Failed())) {
+            return err.StealNSResult();
+        }
     }
 
     // Observe the document so we know when to switch to "normal" view
@@ -200,9 +212,15 @@ nsXMLPrettyPrinter::PrettyPrint(nsIDocument* aDocument,
 void
 nsXMLPrettyPrinter::MaybeUnhook(nsIContent* aContent)
 {
-    // If there either aContent is null (the document-node was modified) or
-    // there isn't a binding parent we know it's non-anonymous content.
-    if ((!aContent || !aContent->GetBindingParent()) && !mUnhookPending) {
+    // If aContent is null, the document-node was modified.
+    // If it is not null but in the shadow tree, the <scrollbar> NACs,
+    // or the XBL binding, the change was in the generated content, and
+    // it should be ignored.
+    bool isGeneratedContent = !aContent ?
+        false :
+        aContent->GetBindingParent() || aContent->IsInShadowTree();
+
+    if (!isGeneratedContent && !mUnhookPending) {
         // Can't blindly to mUnhookPending after AddScriptRunner,
         // since AddScriptRunner _could_ in theory run us
         // synchronously
@@ -219,6 +237,10 @@ nsXMLPrettyPrinter::Unhook()
     nsCOMPtr<Element> element = mDocument->GetDocumentElement();
 
     if (element) {
+        // Remove the shadow root
+        element->UnattachShadow();
+
+        // Remove the bound XBL binding
         mDocument->BindingManager()->ClearBinding(element);
     }
 

dom/xml/nsXMLPrettyPrinter.h

@@ -44,7 +44,7 @@ private:
 
     /**
      * Signals for unhooking by setting mUnhookPending if the node changed is
-     * non-anonymous content.
+     * not in the shadow root tree nor in anonymous content.
      *
      * @param aContent  content that has changed
      */

dom/xml/resources/XMLMonoPrint.css

@@ -1,10 +0,0 @@
-@charset "UTF-8";
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#tree,
-.expandable-opening::-moz-list-bullet {
-  font-family: monospace;
-  white-space: pre;
-}

dom/xml/resources/XMLPrettyPrint.xml

@@ -15,7 +15,12 @@
     <handlers>
       <handler event="prettyprint-dom-created" allowuntrusted="false">
         <![CDATA[
-          document.getAnonymousNodes(this).item(0).appendChild(event.detail);
+          let container = document.getAnonymousNodes(this).item(0);
+          // Take the child nodes from the passed <div id="top">
+          // and append them to our own.
+          for (let el of event.detail.childNodes) {
+            container.appendChild(el);
+          }
         ]]>
       </handler>
     </handlers>

dom/xml/resources/XMLPrettyPrint.xsl

@@ -17,16 +17,19 @@
   <xsl:output method="xml"/>
 
   <xsl:template match="/">
-    <link href="chrome://global/content/xml/XMLPrettyPrint.css" type="text/css" rel="stylesheet"/>
-    <link title="Monospace" href="chrome://global/content/xml/XMLMonoPrint.css" type="text/css" rel="alternate stylesheet"/>
-    <div id="header" dir="&locale.dir;">
-      <p>
-        &xml.nostylesheet;
-      </p>
+    <div id="top">
+      <style>
+        @import url("chrome://global/content/xml/XMLPrettyPrint.css");
+      </style>
+      <div id="header" dir="&locale.dir;">
+        <p>
+          &xml.nostylesheet;
+        </p>
+      </div>
+      <main id="tree" class="highlight">
+        <xsl:apply-templates/>
+      </main>
     </div>
-    <main id="tree" class="highlight">
-      <xsl:apply-templates/>
-    </main>
   </xsl:template>
 
   <xsl:template match="*">

dom/xml/resources/jar.mn

@@ -4,6 +4,5 @@
 
 toolkit.jar:
     content/global/xml/XMLPrettyPrint.css                 (XMLPrettyPrint.css)
-    content/global/xml/XMLMonoPrint.css                   (XMLMonoPrint.css)
-    content/global/xml/XMLPrettyPrint.xml                 (XMLPrettyPrint.xml)
     content/global/xml/XMLPrettyPrint.xsl                 (XMLPrettyPrint.xsl)
+    content/global/xml/XMLPrettyPrint.xml                 (XMLPrettyPrint.xml)