dom/html/HTMLMetaElement.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "mozilla/AsyncEventDispatcher.h"
   8 #include "mozilla/dom/BindContext.h"
   9 #include "mozilla/dom/HTMLMetaElement.h"
  10 #include "mozilla/dom/HTMLMetaElementBinding.h"
  11 #include "mozilla/dom/nsCSPService.h"
  12 #include "mozilla/dom/nsCSPUtils.h"
  13 #include "mozilla/dom/ViewportMetaData.h"
  14 #include "mozilla/Logging.h"
  15 #include "mozilla/StaticPrefs_security.h"
  16 #include "nsContentUtils.h"
  17 #include "nsSandboxFlags.h"
  18 #include "nsStyleConsts.h"
  19 #include "nsIXMLContentSink.h"
  20
  21 static mozilla::LazyLogModule gMetaElementLog("nsMetaElement");
  22 #define LOG(msg) MOZ_LOG(gMetaElementLog, mozilla::LogLevel::Debug, msg)
  23 #define LOG_ENABLED() MOZ_LOG_TEST(gMetaElementLog, mozilla::LogLevel::Debug)
  24
  25 NS_IMPL_NS_NEW_HTML_ELEMENT(Meta)
  26
  27 namespace mozilla::dom {
  28
  29 HTMLMetaElement::HTMLMetaElement(
  30     already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo)
  31     : nsGenericHTMLElement(std::move(aNodeInfo)) {}
  32
  33 HTMLMetaElement::~HTMLMetaElement() = default;
  34
  35 NS_IMPL_ELEMENT_CLONE(HTMLMetaElement)
  36
  37 void HTMLMetaElement::AfterSetAttr(int32_t aNameSpaceID, nsAtom* aName,
  38                                    const nsAttrValue* aValue,
  39                                    const nsAttrValue* aOldValue,
  40                                    nsIPrincipal* aSubjectPrincipal,
  41                                    bool aNotify) {
  42   if (aNameSpaceID == kNameSpaceID_None) {
  43     if (Document* document = GetUncomposedDoc()) {
  44       if (aName == nsGkAtoms::content) {
  45         if (const nsAttrValue* name = GetParsedAttr(nsGkAtoms::name)) {
  46           MetaAddedOrChanged(*document, *name, ChangeKind::ContentChange);
  47         }
  48         CreateAndDispatchEvent(*document, u"DOMMetaChanged"_ns);
  49       } else if (aName == nsGkAtoms::name) {
  50         if (aOldValue) {
  51           MetaRemoved(*document, *aOldValue, ChangeKind::NameChange);
  52         }
  53         if (aValue) {
  54           MetaAddedOrChanged(*document, *aValue, ChangeKind::NameChange);
  55         }
  56         CreateAndDispatchEvent(*document, u"DOMMetaChanged"_ns);
  57       }
  58     }
  59   }
  60
  61   return nsGenericHTMLElement::AfterSetAttr(
  62       aNameSpaceID, aName, aValue, aOldValue, aSubjectPrincipal, aNotify);
  63 }
  64
  65 nsresult HTMLMetaElement::BindToTree(BindContext& aContext, nsINode& aParent) {
  66   nsresult rv = nsGenericHTMLElement::BindToTree(aContext, aParent);
  67   NS_ENSURE_SUCCESS(rv, rv);
  68   if (!IsInUncomposedDoc()) {
  69     return rv;
  70   }
  71   Document& doc = aContext.OwnerDoc();
  72
  73   bool shouldProcessMeta = true;
  74   // We don't want to call ProcessMETATag when we are pretty print
  75   // the document
  76   if (doc.IsXMLDocument()) {
  77     if (nsCOMPtr<nsIXMLContentSink> xmlSink =
  78             do_QueryInterface(doc.GetCurrentContentSink())) {
  79       if (xmlSink->IsPrettyPrintXML() &&
  80           xmlSink->IsPrettyPrintHasSpecialRoot()) {
  81         shouldProcessMeta = false;
  82       }
  83     }
  84   }
  85
  86   if (shouldProcessMeta) {
  87     doc.ProcessMETATag(this);
  88   }
  89
  90   if (AttrValueIs(kNameSpaceID_None, nsGkAtoms::httpEquiv, nsGkAtoms::headerCSP,
  91                   eIgnoreCase)) {
  92     // only accept <meta http-equiv="Content-Security-Policy" content=""> if it
  93     // appears in the <head> element.
  94     Element* headElt = doc.GetHeadElement();
  95     if (headElt && IsInclusiveDescendantOf(headElt)) {
  96       nsAutoString content;
  97       GetContent(content);
  98
  99       if (LOG_ENABLED()) {
 100         nsAutoCString documentURIspec;
 101         if (nsIURI* documentURI = doc.GetDocumentURI()) {
 102           documentURI->GetAsciiSpec(documentURIspec);
 103         }
 104
 105         LOG(
 106             ("HTMLMetaElement %p sets CSP '%s' on document=%p, "
 107              "document-uri=%s",
 108              this, NS_ConvertUTF16toUTF8(content).get(), &doc,
 109              documentURIspec.get()));
 110       }
 111       CSP_ApplyMetaCSPToDoc(doc, content);
 112     }
 113   }
 114
 115   if (const nsAttrValue* name = GetParsedAttr(nsGkAtoms::name)) {
 116     MetaAddedOrChanged(doc, *name, ChangeKind::TreeChange);
 117   }
 118   CreateAndDispatchEvent(doc, u"DOMMetaAdded"_ns);
 119   return rv;
 120 }
 121
 122 void HTMLMetaElement::UnbindFromTree(UnbindContext& aContext) {
 123   if (Document* oldDoc = GetUncomposedDoc()) {
 124     if (const nsAttrValue* name = GetParsedAttr(nsGkAtoms::name)) {
 125       MetaRemoved(*oldDoc, *name, ChangeKind::TreeChange);
 126     }
 127     CreateAndDispatchEvent(*oldDoc, u"DOMMetaRemoved"_ns);
 128   }
 129   nsGenericHTMLElement::UnbindFromTree(aContext);
 130 }
 131
 132 void HTMLMetaElement::CreateAndDispatchEvent(Document&,
 133                                              const nsAString& aEventName) {
 134   AsyncEventDispatcher::RunDOMEventWhenSafe(*this, aEventName, CanBubble::eYes,
 135                                             ChromeOnlyDispatch::eYes);
 136 }
 137
 138 JSObject* HTMLMetaElement::WrapNode(JSContext* aCx,
 139                                     JS::Handle<JSObject*> aGivenProto) {
 140   return HTMLMetaElement_Binding::Wrap(aCx, this, aGivenProto);
 141 }
 142
 143 void HTMLMetaElement::MetaAddedOrChanged(Document& aDoc,
 144                                          const nsAttrValue& aName,
 145                                          ChangeKind aChangeKind) {
 146   nsAutoString content;
 147   const bool hasContent = GetAttr(nsGkAtoms::content, content);
 148   if (aName.Equals(nsGkAtoms::viewport, eIgnoreCase)) {
 149     if (hasContent) {
 150       aDoc.SetMetaViewportData(MakeUnique<ViewportMetaData>(content));
 151     }
 152     return;
 153   }
 154
 155   if (aName.Equals(nsGkAtoms::referrer, eIgnoreCase)) {
 156     content = nsContentUtils::TrimWhitespace<nsContentUtils::IsHTMLWhitespace>(
 157         content);
 158     return aDoc.UpdateReferrerInfoFromMeta(content,
 159                                            /* aPreload = */ false);
 160   }
 161   if (aName.Equals(nsGkAtoms::color_scheme, eIgnoreCase)) {
 162     if (aChangeKind != ChangeKind::ContentChange) {
 163       return aDoc.AddColorSchemeMeta(*this);
 164     }
 165     return aDoc.RecomputeColorScheme();
 166   }
 167 }
 168
 169 void HTMLMetaElement::MetaRemoved(Document& aDoc, const nsAttrValue& aName,
 170                                   ChangeKind aChangeKind) {
 171   MOZ_ASSERT(aChangeKind != ChangeKind::ContentChange,
 172              "Content change can't trigger removal");
 173   if (aName.Equals(nsGkAtoms::color_scheme, eIgnoreCase)) {
 174     return aDoc.RemoveColorSchemeMeta(*this);
 175   }
 176 }
 177
 178 }  // namespace mozilla::dom