Bug 278443: Use an Arena to allocate nsNodeInfos. Patch by smaug@welho.com.

r=sicking sr=peterv

content/base/src/nsNodeInfo.cpp

@@ -45,6 +45,18 @@
 #include "nsCRT.h"
 #include "nsContentUtils.h"
 #include "nsReadableUtils.h"
+#include NEW_H
+#include "nsFixedSizeAllocator.h"
+
+static const size_t kNodeInfoPoolSizes[] = {
+  sizeof(nsNodeInfo)
+};
+
+static const PRInt32 kNodeInfoPoolInitialSize = 
+  (NS_SIZE_IN_HEAP(sizeof(nsNodeInfo))) * 64;
+
+// static
+nsFixedSizeAllocator* nsNodeInfo::sNodeInfoPool = nsnull;
 
 // static
 nsNodeInfo*
@@ -57,34 +69,30 @@ nsNodeInfo::Create()
     sCachedNodeInfo = nsnull;
     return nodeInfo;
   }
+  
+  if (!sNodeInfoPool) {
+    sNodeInfoPool = new nsFixedSizeAllocator();
+    if (!sNodeInfoPool)
+      return nsnull;
+
+    nsresult rv = sNodeInfoPool->Init("NodeInfo Pool", kNodeInfoPoolSizes,
+                                      1, kNodeInfoPoolInitialSize);
+    if (NS_FAILED(rv)) {
+      delete sNodeInfoPool;
+      sNodeInfoPool = nsnull;
+      return nsnull;
+    }
+  }
 
   // Create a new one
-  return new nsNodeInfo();
+  void* place = sNodeInfoPool->Alloc(sizeof(nsNodeInfo));
+  return place ? new (place) nsNodeInfo() : nsnull;
 }
 
 nsNodeInfo::nsNodeInfo()
 {
 }
 
-
-nsNodeInfo::~nsNodeInfo()
-{
-  Clear();
-}
-
-void
-nsNodeInfo::Clear()
-{
-  if (mOwnerManager) {
-    mOwnerManager->RemoveNodeInfo(this);
-    NS_RELEASE(mOwnerManager);
-  }
-
-  NS_IF_RELEASE(mInner.mName);
-  NS_IF_RELEASE(mInner.mPrefix);
-}
-
-
 nsresult
 nsNodeInfo::Init(nsIAtom *aName, nsIAtom *aPrefix, PRInt32 aNamespaceID,
                  nsNodeInfoManager *aOwnerManager)
@@ -269,16 +277,33 @@ void
 nsNodeInfo::ClearCache()
 {
   // Clear our cache.
-  delete sCachedNodeInfo;
-  sCachedNodeInfo = nsnull;
+  if (sNodeInfoPool) {
+    if (sCachedNodeInfo) {
+      sNodeInfoPool->Free(sCachedNodeInfo, sizeof(nsNodeInfo));
+      sCachedNodeInfo = nsnull;
+    }
+
+    delete sNodeInfoPool;
+    sNodeInfoPool = nsnull;
+  }
 }
 
 void
 nsNodeInfo::LastRelease()
 {
+  // Clear object so that we have no references to anything external
+  if (mOwnerManager) {
+    mOwnerManager->RemoveNodeInfo(this);
+    NS_RELEASE(mOwnerManager);
+  }
+
+  NS_IF_RELEASE(mInner.mName);
+  NS_IF_RELEASE(mInner.mPrefix);
+  mIDAttributeAtom = nsnull;
+
   if (sCachedNodeInfo) {
     // No room in cache
-    delete this;
+    sNodeInfoPool->Free(this, sizeof(nsNodeInfo));
     return;
   }
 
@@ -286,9 +311,6 @@ nsNodeInfo::LastRelease()
   // this instance in the cache instead of deleting it.
   sCachedNodeInfo = this;
 
-  // Clear object so that we have no references to anything external
-  Clear();
-
   // The refcount balancing and destructor re-entrancy protection
   // code in Release() sets mRefCnt to 1 so we have to set it to 0
   // here to prevent leaks

content/base/src/nsNodeInfo.h

@@ -44,6 +44,8 @@
 #include "nsIAtom.h"
 #include "nsCOMPtr.h"
 
+class nsFixedSizeAllocator;
+
 class nsNodeInfo : public nsINodeInfo
 {
 public:
@@ -78,8 +80,6 @@ public:
   static nsNodeInfo *Create();
 private:
   nsNodeInfo();
-protected:
-  virtual ~nsNodeInfo();
 
 public:
   /*
@@ -98,10 +98,10 @@ public:
   static void ClearCache();
 
 private:
-  void Clear();
-
   static nsNodeInfo *sCachedNodeInfo;
 
+  static nsFixedSizeAllocator* sNodeInfoPool;
+
   /**
    * This method gets called by Release() when it's time to delete 
    * this object, instead of always deleting the object we'll put the