Bug 1134648, handle dynamic changes to rel=dns-prefetch, r=bz

--HG--
extra : rebase_source : 817f331da1cfadb0833a14a3a18c5d4769752b79

dom/base/Link.cpp

@@ -14,6 +14,7 @@
 
 #include "nsEscape.h"
 #include "nsGkAtoms.h"
+#include "nsHTMLDNSPrefetch.h"
 #include "nsString.h"
 #include "mozAutoDocUpdate.h"
 
@@ -46,6 +47,31 @@ Link::ElementHasHref() const
             mElement->HasAttr(kNameSpaceID_XLink, nsGkAtoms::href)));
 }
 
+void
+Link::TryDNSPrefetch()
+{
+  MOZ_ASSERT(mElement->IsInComposedDoc());
+  if (ElementHasHref() && nsHTMLDNSPrefetch::IsAllowed(mElement->OwnerDoc())) {
+    nsHTMLDNSPrefetch::PrefetchLow(this);
+  }
+}
+
+void
+Link::CancelDNSPrefetch(nsWrapperCache::FlagsType aDeferredFlag,
+                        nsWrapperCache::FlagsType aRequestedFlag)
+{
+  // If prefetch was deferred, clear flag and move on
+  if (mElement->HasFlag(aDeferredFlag)) {
+    mElement->UnsetFlags(aDeferredFlag);
+    // Else if prefetch was requested, clear flag and send cancellation
+  } else if (mElement->HasFlag(aRequestedFlag)) {
+    mElement->UnsetFlags(aRequestedFlag);
+    // Possible that hostname could have changed since binding, but since this
+    // covers common cases, most DNS prefetch requests will be canceled
+    nsHTMLDNSPrefetch::CancelPrefetchLow(this, NS_ERROR_ABORT);
+  }
+}
+
 void
 Link::SetLinkState(nsLinkState aState)
 {

dom/base/Link.h

@@ -111,6 +111,11 @@ public:
 
   bool ElementHasHref() const;
 
+  void TryDNSPrefetch();
+
+  void CancelDNSPrefetch(nsWrapperCache::FlagsType aDeferredFlag,
+                         nsWrapperCache::FlagsType aRequestedFlag);
+
 protected:
   virtual ~Link();
 

dom/html/HTMLAnchorElement.cpp

@@ -158,9 +158,7 @@ HTMLAnchorElement::BindToTree(nsIDocument* aDocument, nsIContent* aParent,
   nsIDocument* doc = GetComposedDoc();
   if (doc) {
     doc->RegisterPendingLinkUpdate(this);
-    if (nsHTMLDNSPrefetch::IsAllowed(OwnerDoc())) {
-      nsHTMLDNSPrefetch::PrefetchLow(this);
-    }
+    TryDNSPrefetch();
   }
 
   return rv;
@@ -172,18 +170,9 @@ HTMLAnchorElement::UnbindFromTree(bool aDeep, bool aNullParent)
   // Cancel any DNS prefetches
   // Note: Must come before ResetLinkState.  If called after, it will recreate
   // mCachedURI based on data that is invalid - due to a call to GetHostname.
+  CancelDNSPrefetch(HTML_ANCHOR_DNS_PREFETCH_DEFERRED,
+                    HTML_ANCHOR_DNS_PREFETCH_REQUESTED);
 
-  // If prefetch was deferred, clear flag and move on
-  if (HasFlag(HTML_ANCHOR_DNS_PREFETCH_DEFERRED))
-    UnsetFlags(HTML_ANCHOR_DNS_PREFETCH_DEFERRED);
-  // Else if prefetch was requested, clear flag and send cancellation
-  else if (HasFlag(HTML_ANCHOR_DNS_PREFETCH_REQUESTED)) {
-    UnsetFlags(HTML_ANCHOR_DNS_PREFETCH_REQUESTED);
-    // Possible that hostname could have changed since binding, but since this
-    // covers common cases, most DNS prefetch requests will be canceled
-    nsHTMLDNSPrefetch::CancelPrefetchLow(this, NS_ERROR_ABORT);
-  }
-  
   // If this link is ever reinserted into a document, it might
   // be under a different xml:base, so forget the cached state now.
   Link::ResetLinkState(false, Link::ElementHasHref());
@@ -406,6 +395,10 @@ HTMLAnchorElement::SetAttr(int32_t aNameSpaceID, nsIAtom* aName,
         reset = true;
       }
     }
+    if (reset) {
+      CancelDNSPrefetch(HTML_ANCHOR_DNS_PREFETCH_DEFERRED,
+                        HTML_ANCHOR_DNS_PREFETCH_REQUESTED);
+    }
   }
 
   nsresult rv = nsGenericHTMLElement::SetAttr(aNameSpaceID, aName, aPrefix,
@@ -418,6 +411,9 @@ HTMLAnchorElement::SetAttr(int32_t aNameSpaceID, nsIAtom* aName,
   // to get updated information about the visitedness from Link.
   if (reset) {
     Link::ResetLinkState(!!aNotify, true);
+    if (IsInComposedDoc()) {
+      TryDNSPrefetch();
+    }
   }
 
   return rv;
@@ -427,6 +423,14 @@ nsresult
 HTMLAnchorElement::UnsetAttr(int32_t aNameSpaceID, nsIAtom* aAttribute,
                              bool aNotify)
 {
+  bool href =
+    (aAttribute == nsGkAtoms::href && kNameSpaceID_None == aNameSpaceID);
+
+  if (href) {
+    CancelDNSPrefetch(HTML_ANCHOR_DNS_PREFETCH_DEFERRED,
+                      HTML_ANCHOR_DNS_PREFETCH_REQUESTED);
+  }
+
   nsresult rv = nsGenericHTMLElement::UnsetAttr(aNameSpaceID, aAttribute,
                                                 aNotify);
 
@@ -435,7 +439,7 @@ HTMLAnchorElement::UnsetAttr(int32_t aNameSpaceID, nsIAtom* aAttribute,
   // we will need the updated attribute value because notifying the document
   // that content states have changed will call IntrinsicState, which will try
   // to get updated information about the visitedness from Link.
-  if (aAttribute == nsGkAtoms::href && kNameSpaceID_None == aNameSpaceID) {
+  if (href) {
     Link::ResetLinkState(!!aNotify, false);
   }
 

dom/html/HTMLLinkElement.cpp

@@ -28,6 +28,22 @@
 #include "nsStyleConsts.h"
 #include "nsUnicharUtils.h"
 
+#define LINK_ELEMENT_FLAG_BIT(n_) \
+  NODE_FLAG_BIT(ELEMENT_TYPE_SPECIFIC_BITS_OFFSET + (n_))
+
+// Link element specific bits
+enum {
+  // Indicates that a DNS Prefetch has been requested from this Link element.
+  HTML_LINK_DNS_PREFETCH_REQUESTED = LINK_ELEMENT_FLAG_BIT(0),
+
+  // Indicates that a DNS Prefetch was added to the deferral queue
+  HTML_LINK_DNS_PREFETCH_DEFERRED =  LINK_ELEMENT_FLAG_BIT(1)
+};
+
+#undef LINK_ELEMENT_FLAG_BIT
+
+ASSERT_NODE_FLAGS_SPACE(ELEMENT_TYPE_SPECIFIC_BITS_OFFSET + 2);
+
 NS_IMPL_NS_NEW_HTML_ELEMENT(Link)
 
 namespace mozilla {
@@ -126,6 +142,26 @@ HTMLLinkElement::SetItemValueText(const nsAString& aValue)
   SetHref(aValue);
 }
 
+void
+HTMLLinkElement::OnDNSPrefetchRequested()
+{
+  UnsetFlags(HTML_LINK_DNS_PREFETCH_DEFERRED);
+  SetFlags(HTML_LINK_DNS_PREFETCH_REQUESTED);
+}
+
+void
+HTMLLinkElement::OnDNSPrefetchDeferred()
+{
+  UnsetFlags(HTML_LINK_DNS_PREFETCH_REQUESTED);
+  SetFlags(HTML_LINK_DNS_PREFETCH_DEFERRED);
+}
+
+bool
+HTMLLinkElement::HasDeferredDNSPrefetchRequest()
+{
+  return HasFlag(HTML_LINK_DNS_PREFETCH_DEFERRED);
+}
+
 nsresult
 HTMLLinkElement::BindToTree(nsIDocument* aDocument, nsIContent* aParent,
                             nsIContent* aBindingParent,
@@ -145,6 +181,9 @@ HTMLLinkElement::BindToTree(nsIDocument* aDocument, nsIContent* aParent,
 
   if (IsInComposedDoc()) {
     UpdatePreconnect();
+    if (HasDNSPrefetchRel()) {
+      TryDNSPrefetch();
+    }
   }
 
   void (HTMLLinkElement::*update)() = &HTMLLinkElement::UpdateStyleSheetInternal;
@@ -173,6 +212,12 @@ HTMLLinkElement::LinkRemoved()
 void
 HTMLLinkElement::UnbindFromTree(bool aDeep, bool aNullParent)
 {
+  // Cancel any DNS prefetches
+  // Note: Must come before ResetLinkState.  If called after, it will recreate
+  // mCachedURI based on data that is invalid - due to a call to GetHostname.
+  CancelDNSPrefetch(HTML_LINK_DNS_PREFETCH_DEFERRED,
+                    HTML_LINK_DNS_PREFETCH_REQUESTED);
+
   // If this link is ever reinserted into a document, it might
   // be under a different xml:base, so forget the cached state now.
   Link::ResetLinkState(false, Link::ElementHasHref());
@@ -322,6 +367,32 @@ HTMLLinkElement::UpdatePreconnect()
   }
 }
 
+bool
+HTMLLinkElement::HasDNSPrefetchRel()
+{
+  nsAutoString rel;
+  if (GetAttr(kNameSpaceID_None, nsGkAtoms::rel, rel)) {
+    return !!(ParseLinkTypes(rel, NodePrincipal()) &
+              nsStyleLinkElement::eDNS_PREFETCH);
+  }
+
+  return false;
+}
+
+nsresult
+HTMLLinkElement::BeforeSetAttr(int32_t aNameSpaceID, nsIAtom* aName,
+                               nsAttrValueOrString* aValue, bool aNotify)
+{
+  if (aNameSpaceID == kNameSpaceID_None &&
+      (aName == nsGkAtoms::href || aName == nsGkAtoms::rel)) {
+    CancelDNSPrefetch(HTML_LINK_DNS_PREFETCH_DEFERRED,
+                      HTML_LINK_DNS_PREFETCH_REQUESTED);
+  }
+
+  return nsGenericHTMLElement::BeforeSetAttr(aNameSpaceID, aName,
+                                             aValue, aNotify);
+}
+
 nsresult
 HTMLLinkElement::AfterSetAttr(int32_t aNameSpaceID, nsIAtom* aName,
                               const nsAttrValue* aValue, bool aNotify)
@@ -368,6 +439,11 @@ HTMLLinkElement::AfterSetAttr(int32_t aNameSpaceID, nsIAtom* aName,
         }
       }
 
+      if ((aName == nsGkAtoms::rel || aName == nsGkAtoms::href) &&
+          HasDNSPrefetchRel() && IsInComposedDoc()) {
+        TryDNSPrefetch();
+      }
+
       UpdateStyleSheetInternal(nullptr, nullptr,
                                dropSheet ||
                                (aName == nsGkAtoms::title ||

dom/html/HTMLLinkElement.h

@@ -61,6 +61,9 @@ public:
                               bool aCompileEventHandlers) override;
   virtual void UnbindFromTree(bool aDeep = true,
                               bool aNullParent = true) override;
+  virtual nsresult BeforeSetAttr(int32_t aNameSpaceID, nsIAtom* aName,
+                                 nsAttrValueOrString* aValue,
+                                 bool aNotify) override;
   virtual nsresult AfterSetAttr(int32_t aNameSpaceID, nsIAtom* aName,
                                 const nsAttrValue* aValue,
                                 bool aNotify) override;
@@ -77,6 +80,10 @@ public:
 
   void CreateAndDispatchEvent(nsIDocument* aDoc, const nsAString& aEventName);
 
+  virtual void OnDNSPrefetchDeferred() override;
+  virtual void OnDNSPrefetchRequested() override;
+  virtual bool HasDeferredDNSPrefetchRequest() override;
+
   // WebIDL
   bool Disabled();
   void SetDisabled(bool aDisabled);
@@ -166,6 +173,9 @@ protected:
   // nsGenericHTMLElement
   virtual void GetItemValueText(DOMString& text) override;
   virtual void SetItemValueText(const nsAString& text) override;
+
+  bool HasDNSPrefetchRel();
+
   RefPtr<nsDOMTokenList > mRelList;
 private:
   RefPtr<ImportLoader> mImportLoader;

dom/xml/nsXMLContentSink.cpp

@@ -611,13 +611,6 @@ nsXMLContentSink::CloseElement(nsIContent* aContent)
             PrefetchHref(hrefVal, aContent, hasPrefetch);
           }
         }
-        if (linkTypes & nsStyleLinkElement::eDNS_PREFETCH) {
-          nsAutoString hrefVal;
-          aContent->GetAttr(kNameSpaceID_None, nsGkAtoms::href, hrefVal);
-          if (!hrefVal.IsEmpty()) {
-            PrefetchDNS(hrefVal);
-          }
-        }
       }
     }
   }

parser/html/nsHtml5DocumentBuilder.cpp

@@ -96,13 +96,6 @@ nsHtml5DocumentBuilder::UpdateStyleSheet(nsIContent* aElement)
           PrefetchHref(hrefVal, aElement, hasPrefetch);
         }
       }
-      if (linkTypes & nsStyleLinkElement::eDNS_PREFETCH) {
-        nsAutoString hrefVal;
-        aElement->GetAttr(kNameSpaceID_None, nsGkAtoms::href, hrefVal);
-        if (!hrefVal.IsEmpty()) {
-          PrefetchDNS(hrefVal);
-        }
-      }
     }
   }