Merge pull request #1115 from win7-7/NS_Atomize-cache

Add NS_Atomize cache for main thread use

7 files changed, 74 insertions, 21 deletions

diff --git a/dom/base/Element.cpp b/dom/base/Element.cpp
index 5c3277e841..0054f48006 100644
--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -1283,7 +1283,7 @@ Element::ToggleAttribute(const nsAString& aName,
     if (aForce.WasPassed() && !aForce.Value()) {
       return false;
     }
-    nsCOMPtr<nsIAtom> nameAtom = NS_Atomize(nameToUse);
+    nsCOMPtr<nsIAtom> nameAtom = NS_AtomizeMainThread(nameToUse);
     if (!nameAtom) {
       aError.Throw(NS_ERROR_OUT_OF_MEMORY);
       return false;
@@ -1316,7 +1316,7 @@ Element::SetAttribute(const nsAString& aName,
   nsAutoString nameToUse;
   const nsAttrName* name = InternalGetAttrNameFromQName(aName, &nameToUse);
   if (!name) {
-    nsCOMPtr<nsIAtom> nameAtom = NS_Atomize(nameToUse);
+    nsCOMPtr<nsIAtom> nameAtom = NS_AtomizeMainThread(nameToUse);
     if (!nameAtom) {
       aError.Throw(NS_ERROR_OUT_OF_MEMORY);
       return;
@@ -1398,7 +1398,7 @@ Element::GetAttributeNS(const nsAString& aNamespaceURI,
     return;
   }
 
-  nsCOMPtr<nsIAtom> name = NS_Atomize(aLocalName);
+  nsCOMPtr<nsIAtom> name = NS_AtomizeMainThread(aLocalName);
   bool hasAttr = GetAttr(nsid, name, aReturn);
   if (!hasAttr) {
     SetDOMStringToNull(aReturn);
@@ -1430,7 +1430,7 @@ Element::RemoveAttributeNS(const nsAString& aNamespaceURI,
                            const nsAString& aLocalName,
                            ErrorResult& aError)
 {
-  nsCOMPtr<nsIAtom> name = NS_Atomize(aLocalName);
+  nsCOMPtr<nsIAtom> name = NS_AtomizeMainThread(aLocalName);
   int32_t nsid =
     nsContentUtils::NameSpaceManager()->GetNameSpaceID(aNamespaceURI,
                                                        nsContentUtils::IsChromeDoc(OwnerDoc()));
@@ -1518,7 +1518,7 @@ Element::HasAttributeNS(const nsAString& aNamespaceURI,
     return false;
   }
 
-  nsCOMPtr<nsIAtom> name = NS_Atomize(aLocalName);
+  nsCOMPtr<nsIAtom> name = NS_AtomizeMainThread(aLocalName);
   return HasAttr(nsid, name);
 }
 
diff --git a/dom/base/nsAttrValue.cpp b/dom/base/nsAttrValue.cpp
index 8eb1aaf974..ebddcb7edf 100644
--- a/dom/base/nsAttrValue.cpp
+++ b/dom/base/nsAttrValue.cpp
@@ -742,7 +742,7 @@ nsAttrValue::GetAsAtom() const
 {
   switch (Type()) {
     case eString:
-      return NS_Atomize(GetStringValue());
+      return NS_AtomizeMainThread(GetStringValue());
 
     case eAtom:
       {
@@ -754,7 +754,7 @@ nsAttrValue::GetAsAtom() const
       {
         nsAutoString val;
         ToString(val);
-        return NS_Atomize(val);
+        return NS_AtomizeMainThread(val);
       }
   }
 }
@@ -1267,7 +1267,7 @@ nsAttrValue::ParseAtomArray(const nsAString& aValue)
     ++iter;
   } while (iter != end && !nsContentUtils::IsHTMLWhitespace(*iter));
 
-  nsCOMPtr<nsIAtom> classAtom = NS_Atomize(Substring(start, iter));
+  nsCOMPtr<nsIAtom> classAtom = NS_AtomizeMainThread(Substring(start, iter));
   if (!classAtom) {
     Reset();
     return;
@@ -1308,7 +1308,7 @@ nsAttrValue::ParseAtomArray(const nsAString& aValue)
       ++iter;
     } while (iter != end && !nsContentUtils::IsHTMLWhitespace(*iter));
 
-    classAtom = NS_Atomize(Substring(start, iter));
+    classAtom = NS_AtomizeMainThread(Substring(start, iter));
 
     if (!array->AppendElement(classAtom)) {
       Reset();
@@ -1757,7 +1757,7 @@ nsAttrValue::SetMiscAtomOrString(const nsAString* aValue)
                  "Empty string?");
     MiscContainer* cont = GetMiscContainer();
     if (len <= NS_ATTRVALUE_MAX_STRINGLENGTH_ATOM) {
-      nsCOMPtr<nsIAtom> atom = NS_Atomize(*aValue);
+      nsCOMPtr<nsIAtom> atom = NS_AtomizeMainThread(*aValue);
       if (atom) {
         cont->mStringBits =
           reinterpret_cast<uintptr_t>(atom.forget().take()) | eAtomBase;
diff --git a/dom/base/nsContentUtils.cpp b/dom/base/nsContentUtils.cpp
index 3696195ddb..1f9c179472 100644
--- a/dom/base/nsContentUtils.cpp
+++ b/dom/base/nsContentUtils.cpp
@@ -2947,11 +2947,11 @@ nsContentUtils::SplitQName(const nsIContent* aNamespaceResolver,
     if (*aNamespace == kNameSpaceID_Unknown)
       return NS_ERROR_FAILURE;
 
-    *aLocalName = NS_Atomize(Substring(colon + 1, end)).take();
+    *aLocalName = NS_AtomizeMainThread(Substring(colon + 1, end)).take();
   }
   else {
     *aNamespace = kNameSpaceID_None;
-    *aLocalName = NS_Atomize(aQName).take();
+    *aLocalName = NS_AtomizeMainThread(aQName).take();
   }
   NS_ENSURE_TRUE(aLocalName, NS_ERROR_OUT_OF_MEMORY);
   return NS_OK;
@@ -2976,7 +2976,8 @@ nsContentUtils::GetNodeInfoFromQName(const nsAString& aNamespaceURI,
     const char16_t* end;
     qName.EndReading(end);
 
-    nsCOMPtr<nsIAtom> prefix = NS_Atomize(Substring(qName.get(), colon));
+    nsCOMPtr<nsIAtom> prefix =
+      NS_AtomizeMainThread(Substring(qName.get(), colon));
 
     rv = aNodeInfoManager->GetNodeInfo(Substring(colon + 1, end), prefix,
                                        nsID, aNodeType, aNodeInfo);
@@ -3036,7 +3037,7 @@ nsContentUtils::SplitExpatName(const char16_t *aExpatName, nsIAtom **aPrefix,
     nameStart = (uriEnd + 1);
     if (nameEnd)  {
       const char16_t *prefixStart = nameEnd + 1;
-      *aPrefix = NS_Atomize(Substring(prefixStart, pos)).take();
+      *aPrefix = NS_AtomizeMainThread(Substring(prefixStart, pos)).take();
     }
     else {
       nameEnd = pos;
@@ -3049,7 +3050,7 @@ nsContentUtils::SplitExpatName(const char16_t *aExpatName, nsIAtom **aPrefix,
     nameEnd = pos;
     *aPrefix = nullptr;
   }
-  *aLocalName = NS_Atomize(Substring(nameStart, nameEnd)).take();
+  *aLocalName = NS_AtomizeMainThread(Substring(nameStart, nameEnd)).take();
 }
 
 // static
@@ -3887,7 +3888,8 @@ nsContentUtils::GetEventMessageAndAtom(const nsAString& aName,
   }
 
   *aEventMessage = eUnidentifiedEvent;
-  nsCOMPtr<nsIAtom> atom = NS_Atomize(NS_LITERAL_STRING("on") + aName);
+  nsCOMPtr<nsIAtom> atom =
+    NS_AtomizeMainThread(NS_LITERAL_STRING("on") + aName);
   sUserDefinedEvents->AppendObject(atom);
   mapping.mAtom = atom;
   mapping.mMessage = eUnidentifiedEvent;
@@ -3920,7 +3922,7 @@ nsContentUtils::GetEventMessageAndAtomForListener(const nsAString& aName,
     if (mapping.mMaybeSpecialSVGorSMILEvent) {
       // Try the atom version so that we should get the right message for
       // SVG/SMIL.
-      atom = NS_Atomize(NS_LITERAL_STRING("on") + aName);
+      atom = NS_AtomizeMainThread(NS_LITERAL_STRING("on") + aName);
       msg = GetEventMessage(atom);
     } else {
       atom = mapping.mAtom;
diff --git a/dom/base/nsNodeInfoManager.cpp b/dom/base/nsNodeInfoManager.cpp
index 80f0aa786b..985d540b4c 100644
--- a/dom/base/nsNodeInfoManager.cpp
+++ b/dom/base/nsNodeInfoManager.cpp
@@ -281,7 +281,7 @@ nsNodeInfoManager::GetNodeInfo(const nsAString& aName, nsIAtom *aPrefix,
     return NS_OK;
   }
 
-  nsCOMPtr<nsIAtom> nameAtom = NS_Atomize(aName);
+  nsCOMPtr<nsIAtom> nameAtom = NS_AtomizeMainThread(aName);
   NS_ENSURE_TRUE(nameAtom, NS_ERROR_OUT_OF_MEMORY);
 
   RefPtr<NodeInfo> newNodeInfo =
diff --git a/parser/html/nsHtml5TreeOperation.h b/parser/html/nsHtml5TreeOperation.h
index 0b2970738e..a93f44c46f 100644
--- a/parser/html/nsHtml5TreeOperation.h
+++ b/parser/html/nsHtml5TreeOperation.h
@@ -108,7 +108,7 @@ class nsHtml5TreeOperation {
       }
       nsAutoString str;
       aAtom->ToString(str);
-      return NS_Atomize(str);
+      return NS_AtomizeMainThread(str);
     }
 
     static nsresult AppendTextToTextNode(const char16_t* aBuffer,
diff --git a/xpcom/ds/nsAtomTable.cpp b/xpcom/ds/nsAtomTable.cpp
index 3dd3bd36c1..4c93625ae4 100644
--- a/xpcom/ds/nsAtomTable.cpp
+++ b/xpcom/ds/nsAtomTable.cpp
@@ -364,17 +364,29 @@ static const PLDHashTableOps AtomTableOps = {
 
 //----------------------------------------------------------------------
 
+#define RECENTLY_USED_MAIN_THREAD_ATOM_CACHE_SIZE 31
+static nsIAtom*
+  sRecentlyUsedMainThreadAtoms[RECENTLY_USED_MAIN_THREAD_ATOM_CACHE_SIZE] = {};
+
 void
 DynamicAtom::GCAtomTable()
 {
-  MutexAutoLock lock(*gAtomTableLock);
-  GCAtomTableLocked(lock, GCKind::RegularOperation);
+  if (NS_IsMainThread()) {
+    MutexAutoLock lock(*gAtomTableLock);
+    GCAtomTableLocked(lock, GCKind::RegularOperation);
+  }
 }
 
 void
 DynamicAtom::GCAtomTableLocked(const MutexAutoLock& aProofOfLock,
                                GCKind aKind)
 {
+
+  MOZ_ASSERT(NS_IsMainThread());
+  for (uint32_t i = 0; i < RECENTLY_USED_MAIN_THREAD_ATOM_CACHE_SIZE; ++i) {
+    sRecentlyUsedMainThreadAtoms[i] = nullptr;
+  }
+
   uint32_t removedCount = 0; // Use a non-atomic temporary for cheaper increments.
   nsAutoCString nonZeroRefcountAtoms;
   uint32_t nonZeroRefcountAtomsCount = 0;
@@ -712,6 +724,40 @@ NS_Atomize(const nsAString& aUTF16String)
   return atom.forget();
 }
 
+already_AddRefed<nsIAtom>
+NS_AtomizeMainThread(const nsAString& aUTF16String)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  nsCOMPtr<nsIAtom> retVal;
+  uint32_t hash;
+  AtomTableKey key(aUTF16String.Data(), aUTF16String.Length(), &hash);
+  uint32_t index = hash % RECENTLY_USED_MAIN_THREAD_ATOM_CACHE_SIZE;
+  nsIAtom* atom =
+    sRecentlyUsedMainThreadAtoms[index];
+  if (atom) {
+    uint32_t length = atom->GetLength();
+    if (length == key.mLength &&
+        (memcmp(atom->GetUTF16String(),
+                key.mUTF16String, length * sizeof(char16_t)) == 0)) {
+       retVal = atom;
+       return retVal.forget();
+    }
+  }
+
+  MutexAutoLock lock(*gAtomTableLock);
+  AtomTableEntry* he = static_cast<AtomTableEntry*>(gAtomTable->Add(&key));
+
+  if (he->mAtom) {
+    retVal = he->mAtom;
+  } else {
+    retVal = DynamicAtom::Create(aUTF16String, hash);
+    he->mAtom = retVal;
+  }
+
+  sRecentlyUsedMainThreadAtoms[index] = retVal;
+  return retVal.forget();
+}
+
 nsrefcnt
 NS_GetNumberOfAtoms(void)
 {
diff --git a/xpcom/ds/nsIAtom.idl b/xpcom/ds/nsIAtom.idl
index c025408387..6e8602c42e 100644
--- a/xpcom/ds/nsIAtom.idl
+++ b/xpcom/ds/nsIAtom.idl
@@ -120,6 +120,11 @@ extern already_AddRefed<nsIAtom> NS_Atomize(const char16_t* aUTF16String);
 extern already_AddRefed<nsIAtom> NS_Atomize(const nsAString& aUTF16String);
 
 /**
+ * An optimized version of the method above for the main thread.
+ */
+extern already_AddRefed<nsIAtom> NS_AtomizeMainThread(const nsAString& aUTF16String);
+
+/**
  * Return a count of the total number of atoms currently
  * alive in the system.
  */