1 files changed, 169 insertions, 0 deletions
diff --git a/dom/xml/nsXMLPrettyPrinter.cpp b/dom/xml/nsXMLPrettyPrinter.cpp
new file mode 100644
index 0000000000..c8c941feeb
--- /dev/null
+++ b/dom/xml/nsXMLPrettyPrinter.cpp
@@ -0,0 +1,169 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/. */
+
+#include "nsXMLPrettyPrinter.h"
+#include "nsContentUtils.h"
+#include "nsICSSDeclaration.h"
+#include "nsSyncLoadService.h"
+#include "nsPIDOMWindow.h"
+#include "nsNetUtil.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/dom/ShadowRoot.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/dom/Document.h"
+#include "nsVariant.h"
+#include "mozilla/dom/CustomEvent.h"
+#include "mozilla/dom/DocumentFragment.h"
+#include "mozilla/dom/ScriptSettings.h"
+#include "mozilla/dom/ToJSValue.h"
+#include "mozilla/dom/txMozillaXSLTProcessor.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+NS_IMPL_ISUPPORTS(nsXMLPrettyPrinter, nsIDocumentObserver, nsIMutationObserver)
+
+nsXMLPrettyPrinter::nsXMLPrettyPrinter()
+    : mDocument(nullptr), mUnhookPending(false) {}
+
+nsXMLPrettyPrinter::~nsXMLPrettyPrinter() {
+  NS_ASSERTION(!mDocument, "we shouldn't be referencing the document still");
+}
+
+nsresult nsXMLPrettyPrinter::PrettyPrint(Document* aDocument,
+                                         bool* aDidPrettyPrint) {
+  *aDidPrettyPrint = false;
+
+  // check the pref
+  if (!Preferences::GetBool("layout.xml.prettyprint", true)) {
+    return NS_OK;
+  }
+
+  // Find the root element
+  RefPtr<Element> rootElement = aDocument->GetRootElement();
+  NS_ENSURE_TRUE(rootElement, NS_ERROR_UNEXPECTED);
+
+  // nsXMLContentSink should not ask us to pretty print an XML doc that comes
+  // with a CanAttachShadowDOM() == true root element, but just in case:
+  if (rootElement->CanAttachShadowDOM()) {
+    MOZ_DIAGNOSTIC_ASSERT(false, "We shouldn't be getting this root element");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  // Ok, we should prettyprint. Let's do it!
+  *aDidPrettyPrint = true;
+  nsresult rv = NS_OK;
+
+  // Load the XSLT
+  nsCOMPtr<nsIURI> xslUri;
+  rv = NS_NewURI(getter_AddRefs(xslUri),
+                 "chrome://global/content/xml/XMLPrettyPrint.xsl"_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<Document> xslDocument;
+  rv = nsSyncLoadService::LoadDocument(
+      xslUri, nsIContentPolicy::TYPE_XSLT, nsContentUtils::GetSystemPrincipal(),
+      nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_SEC_CONTEXT_IS_NULL, nullptr,
+      aDocument->CookieJarSettings(), true, ReferrerPolicy::_empty,
+      getter_AddRefs(xslDocument));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Transform the document
+  RefPtr<txMozillaXSLTProcessor> transformer = new txMozillaXSLTProcessor();
+  ErrorResult err;
+  transformer->ImportStylesheet(*xslDocument, err);
+  if (NS_WARN_IF(err.Failed())) {
+    return err.StealNSResult();
+  }
+
+  RefPtr<DocumentFragment> resultFragment =
+      transformer->TransformToFragment(*aDocument, *aDocument, err);
+  if (NS_WARN_IF(err.Failed())) {
+    return err.StealNSResult();
+  }
+
+  // Attach an UA Widget Shadow Root on it.
+  rootElement->AttachAndSetUAShadowRoot(Element::NotifyUAWidgetSetup::No);
+  RefPtr<ShadowRoot> shadowRoot = rootElement->GetShadowRoot();
+  MOZ_RELEASE_ASSERT(shadowRoot && shadowRoot->IsUAWidget(),
+                     "There should be a UA Shadow Root here.");
+
+  // Append the document fragment to the shadow dom.
+  shadowRoot->AppendChild(*resultFragment, err);
+  if (NS_WARN_IF(err.Failed())) {
+    return err.StealNSResult();
+  }
+
+  // Observe the document so we know when to switch to "normal" view
+  aDocument->AddObserver(this);
+  mDocument = aDocument;
+
+  NS_ADDREF_THIS();
+
+  return NS_OK;
+}
+
+void nsXMLPrettyPrinter::MaybeUnhook(nsIContent* aContent) {
+  // If aContent is null, the document-node was modified.
+  // If it is not null but in the shadow tree or the <scrollbar> NACs,
+  // the change was in the generated content, and it should be ignored.
+  bool isGeneratedContent =
+      aContent &&
+      (aContent->IsInNativeAnonymousSubtree() || aContent->IsInShadowTree());
+
+  if (!isGeneratedContent && !mUnhookPending) {
+    // Can't blindly to mUnhookPending after AddScriptRunner,
+    // since AddScriptRunner _could_ in theory run us
+    // synchronously
+    mUnhookPending = true;
+    nsContentUtils::AddScriptRunner(NewRunnableMethod(
+        "nsXMLPrettyPrinter::Unhook", this, &nsXMLPrettyPrinter::Unhook));
+  }
+}
+
+void nsXMLPrettyPrinter::Unhook() {
+  mDocument->RemoveObserver(this);
+  nsCOMPtr<Element> element = mDocument->GetDocumentElement();
+
+  if (element) {
+    // Remove the shadow root
+    element->UnattachShadow();
+  }
+
+  mDocument = nullptr;
+
+  NS_RELEASE_THIS();
+}
+
+void nsXMLPrettyPrinter::AttributeChanged(Element* aElement,
+                                          int32_t aNameSpaceID,
+                                          nsAtom* aAttribute, int32_t aModType,
+                                          const nsAttrValue* aOldValue) {
+  MaybeUnhook(aElement);
+}
+
+void nsXMLPrettyPrinter::ContentAppended(nsIContent* aFirstNewContent) {
+  MaybeUnhook(aFirstNewContent->GetParent());
+}
+
+void nsXMLPrettyPrinter::ContentInserted(nsIContent* aChild) {
+  MaybeUnhook(aChild->GetParent());
+}
+
+void nsXMLPrettyPrinter::ContentRemoved(nsIContent* aChild,
+                                        nsIContent* aPreviousSibling) {
+  MaybeUnhook(aChild->GetParent());
+}
+
+void nsXMLPrettyPrinter::NodeWillBeDestroyed(const nsINode* aNode) {
+  mDocument = nullptr;
+  NS_RELEASE_THIS();
+}
+
+nsresult NS_NewXMLPrettyPrinter(nsXMLPrettyPrinter** aPrinter) {
+  *aPrinter = new nsXMLPrettyPrinter;
+  NS_ADDREF(*aPrinter);
+  return NS_OK;
+}