reduce bloat by not chunk-allocating strings (in |nsStr::Alloc|). Clients that don't benefit from this can explicitly call |SetCapacity|. We may re-introduce this functionality in the append of a single character when no space remains, if it turns out to be a problem. This optimization was suggested by profiling done by sfraser, who now promises to find out where it hurts us.

git-svn-id: svn://10.0.0.236/trunk@72019 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/xpcom/string/obsolete/nsStr.cpp

@@ -656,6 +656,7 @@ PRBool nsStr::Alloc(nsStr& aDest,PRUint32 aCount) {
   static int mAllocCount=0;
   mAllocCount++;
 
+#ifdef NS_USE_CHUNKY_STRING_ALLOCATION
   //we're given the acount value in charunits; now scale up to next multiple.
   PRUint32	theNewCapacity=kDefaultStringSize;
   while(theNewCapacity<aCount){ 
@@ -665,6 +666,10 @@ PRBool nsStr::Alloc(nsStr& aDest,PRUint32 aCount) {
   aDest.mCapacity=theNewCapacity++;
   PRUint32 theSize=(theNewCapacity<<aDest.mCharSize);
   aDest.mStr = (char*)nsMemory::Alloc(theSize);
+#else
+  aDest.mCapacity = aCount;
+  aDest.mStr = (char*)nsMemory::Alloc((aCount+1)<<aDest.mCharSize);
+#endif
 
   if(aDest.mStr) {
     aDest.mOwnsBuffer=1;