dom/xml/nsXMLPrettyPrinter.cpp

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "nsXMLPrettyPrinter.h"
   7 #include "nsContentUtils.h"
   8 #include "nsICSSDeclaration.h"
   9 #include "nsSyncLoadService.h"
  10 #include "nsPIDOMWindow.h"
  11 #include "nsNetUtil.h"
  12 #include "mozilla/dom/Element.h"
  13 #include "mozilla/dom/ShadowRoot.h"
  14 #include "mozilla/Preferences.h"
  15 #include "mozilla/dom/Document.h"
  16 #include "nsVariant.h"
  17 #include "mozilla/dom/CustomEvent.h"
  18 #include "mozilla/dom/DocumentFragment.h"
  19 #include "mozilla/dom/ScriptSettings.h"
  20 #include "mozilla/dom/ToJSValue.h"
  21 #include "mozilla/dom/txMozillaXSLTProcessor.h"
  22
  23 using namespace mozilla;
  24 using namespace mozilla::dom;
  25
  26 NS_IMPL_ISUPPORTS(nsXMLPrettyPrinter, nsIDocumentObserver, nsIMutationObserver)
  27
  28 nsXMLPrettyPrinter::nsXMLPrettyPrinter()
  29     : mDocument(nullptr), mUnhookPending(false) {}
  30
  31 nsXMLPrettyPrinter::~nsXMLPrettyPrinter() {
  32   NS_ASSERTION(!mDocument, "we shouldn't be referencing the document still");
  33 }
  34
  35 nsresult nsXMLPrettyPrinter::PrettyPrint(Document* aDocument,
  36                                          bool* aDidPrettyPrint) {
  37   *aDidPrettyPrint = false;
  38
  39   // check the pref
  40   if (!Preferences::GetBool("layout.xml.prettyprint", true)) {
  41     return NS_OK;
  42   }
  43
  44   // Find the root element
  45   RefPtr<Element> rootElement = aDocument->GetRootElement();
  46   NS_ENSURE_TRUE(rootElement, NS_ERROR_UNEXPECTED);
  47
  48   // nsXMLContentSink should not ask us to pretty print an XML doc that comes
  49   // with a CanAttachShadowDOM() == true root element, but just in case:
  50   if (rootElement->CanAttachShadowDOM()) {
  51     MOZ_DIAGNOSTIC_ASSERT(false, "We shouldn't be getting this root element");
  52     return NS_ERROR_UNEXPECTED;
  53   }
  54
  55   // Ok, we should prettyprint. Let's do it!
  56   *aDidPrettyPrint = true;
  57   nsresult rv = NS_OK;
  58
  59   // Load the XSLT
  60   nsCOMPtr<nsIURI> xslUri;
  61   rv = NS_NewURI(getter_AddRefs(xslUri),
  62                  "chrome://global/content/xml/XMLPrettyPrint.xsl"_ns);
  63   NS_ENSURE_SUCCESS(rv, rv);
  64
  65   nsCOMPtr<Document> xslDocument;
  66   rv = nsSyncLoadService::LoadDocument(
  67       xslUri, nsIContentPolicy::TYPE_XSLT, nsContentUtils::GetSystemPrincipal(),
  68       nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_SEC_CONTEXT_IS_NULL, nullptr,
  69       aDocument->CookieJarSettings(), true, ReferrerPolicy::_empty,
  70       getter_AddRefs(xslDocument));
  71   NS_ENSURE_SUCCESS(rv, rv);
  72
  73   // Transform the document
  74   RefPtr<txMozillaXSLTProcessor> transformer = new txMozillaXSLTProcessor();
  75   ErrorResult err;
  76   transformer->ImportStylesheet(*xslDocument, err);
  77   if (NS_WARN_IF(err.Failed())) {
  78     return err.StealNSResult();
  79   }
  80
  81   RefPtr<DocumentFragment> resultFragment =
  82       transformer->TransformToFragment(*aDocument, *aDocument, err);
  83   if (NS_WARN_IF(err.Failed())) {
  84     return err.StealNSResult();
  85   }
  86
  87   // Attach an UA Widget Shadow Root on it.
  88   rootElement->AttachAndSetUAShadowRoot(Element::NotifyUAWidgetSetup::No);
  89   RefPtr<ShadowRoot> shadowRoot = rootElement->GetShadowRoot();
  90   MOZ_RELEASE_ASSERT(shadowRoot && shadowRoot->IsUAWidget(),
  91                      "There should be a UA Shadow Root here.");
  92
  93   // Append the document fragment to the shadow dom.
  94   shadowRoot->AppendChild(*resultFragment, err);
  95   if (NS_WARN_IF(err.Failed())) {
  96     return err.StealNSResult();
  97   }
  98
  99   // Observe the document so we know when to switch to "normal" view
 100   aDocument->AddObserver(this);
 101   mDocument = aDocument;
 102
 103   NS_ADDREF_THIS();
 104
 105   return NS_OK;
 106 }
 107
 108 void nsXMLPrettyPrinter::MaybeUnhook(nsIContent* aContent) {
 109   // If aContent is null, the document-node was modified.
 110   // If it is not null but in the shadow tree or the <scrollbar> NACs,
 111   // the change was in the generated content, and it should be ignored.
 112   bool isGeneratedContent =
 113       aContent &&
 114       (aContent->IsInNativeAnonymousSubtree() || aContent->IsInShadowTree());
 115
 116   if (!isGeneratedContent && !mUnhookPending) {
 117     // Can't blindly to mUnhookPending after AddScriptRunner,
 118     // since AddScriptRunner _could_ in theory run us
 119     // synchronously
 120     mUnhookPending = true;
 121     nsContentUtils::AddScriptRunner(NewRunnableMethod(
 122         "nsXMLPrettyPrinter::Unhook", this, &nsXMLPrettyPrinter::Unhook));
 123   }
 124 }
 125
 126 void nsXMLPrettyPrinter::Unhook() {
 127   mDocument->RemoveObserver(this);
 128   nsCOMPtr<Element> element = mDocument->GetDocumentElement();
 129
 130   if (element) {
 131     // Remove the shadow root
 132     element->UnattachShadow();
 133   }
 134
 135   mDocument = nullptr;
 136
 137   NS_RELEASE_THIS();
 138 }
 139
 140 void nsXMLPrettyPrinter::AttributeChanged(Element* aElement,
 141                                           int32_t aNameSpaceID,
 142                                           nsAtom* aAttribute, int32_t aModType,
 143                                           const nsAttrValue* aOldValue) {
 144   MaybeUnhook(aElement);
 145 }
 146
 147 void nsXMLPrettyPrinter::ContentAppended(nsIContent* aFirstNewContent) {
 148   MaybeUnhook(aFirstNewContent->GetParent());
 149 }
 150
 151 void nsXMLPrettyPrinter::ContentInserted(nsIContent* aChild) {
 152   MaybeUnhook(aChild->GetParent());
 153 }
 154
 155 void nsXMLPrettyPrinter::ContentRemoved(nsIContent* aChild,
 156                                         nsIContent* aPreviousSibling) {
 157   MaybeUnhook(aChild->GetParent());
 158 }
 159
 160 void nsXMLPrettyPrinter::NodeWillBeDestroyed(const nsINode* aNode) {
 161   mDocument = nullptr;
 162   NS_RELEASE_THIS();
 163 }
 164
 165 nsresult NS_NewXMLPrettyPrinter(nsXMLPrettyPrinter** aPrinter) {
 166   *aPrinter = new nsXMLPrettyPrinter;
 167   NS_ADDREF(*aPrinter);
 168   return NS_OK;
 169 }