Bug 859817 - Make nsStringBuffer::Alloc return already_AddRefed; r=bz

content/base/src/nsAttrValue.cpp

@@ -373,7 +373,7 @@ void
 nsAttrValue::SetTo(const nsAString& aValue)
 {
   ResetIfSet();
-  nsStringBuffer* buf = GetStringBuffer(aValue);
+  nsStringBuffer* buf = GetStringBuffer(aValue).get();
   if (buf) {
     SetPtrValueAndType(buf, eStringBase);
   }
@@ -1526,7 +1526,7 @@ nsAttrValue::ParsePositiveIntValue(const nsAString& aString)
 void
 nsAttrValue::SetColorValue(nscolor aColor, const nsAString& aString)
 {
-  nsStringBuffer* buf = GetStringBuffer(aString);
+  nsStringBuffer* buf = GetStringBuffer(aString).get();
   if (!buf) {
     return;
   }
@@ -1717,7 +1717,7 @@ nsAttrValue::SetMiscAtomOrString(const nsAString* aValue)
           reinterpret_cast<uintptr_t>(atom.forget().get()) | eAtomBase;
       }
     } else {
-      nsStringBuffer* buf = GetStringBuffer(*aValue);
+      nsStringBuffer* buf = GetStringBuffer(*aValue).get();
       if (buf) {
         cont->mStringBits = reinterpret_cast<uintptr_t>(buf) | eStringBase;
       }
@@ -1853,7 +1853,7 @@ nsAttrValue::EnsureEmptyAtomArray()
   return true;
 }
 
-nsStringBuffer*
+already_AddRefed<nsStringBuffer>
 nsAttrValue::GetStringBuffer(const nsAString& aValue) const
 {
   uint32_t len = aValue.Length();
@@ -1861,10 +1861,9 @@ nsAttrValue::GetStringBuffer(const nsAString& aValue) const
     return nullptr;
   }
 
-  nsStringBuffer* buf = nsStringBuffer::FromString(aValue);
+  nsRefPtr<nsStringBuffer> buf = nsStringBuffer::FromString(aValue);
   if (buf && (buf->StorageSize()/sizeof(PRUnichar) - 1) == len) {
-    buf->AddRef();
-    return buf;
+    return buf.forget();
   }
 
   buf = nsStringBuffer::Alloc((len + 1) * sizeof(PRUnichar));
@@ -1874,7 +1873,7 @@ nsAttrValue::GetStringBuffer(const nsAString& aValue) const
   PRUnichar *data = static_cast<PRUnichar*>(buf->Data());
   CopyUnicodeTo(aValue, 0, data, len);
   data[len] = PRUnichar(0);
-  return buf;
+  return buf.forget();
 }
 
 int32_t

content/base/src/nsAttrValue.h

@@ -415,7 +415,8 @@ private:
   // exist already.
   MiscContainer* EnsureEmptyMiscContainer();
   bool EnsureEmptyAtomArray();
-  nsStringBuffer* GetStringBuffer(const nsAString& aValue) const;
+  already_AddRefed<nsStringBuffer>
+    GetStringBuffer(const nsAString& aValue) const;
   // aStrict is set true if stringifying the return value equals with
   // aValue.
   int32_t StringToInteger(const nsAString& aValue,

content/base/src/nsDocumentEncoder.cpp

@@ -1008,7 +1008,7 @@ nsDocumentEncoder::EncodeToString(nsAString& aOutputString)
   nsString output;
   static const size_t bufferSize = 2048;
   if (!mCachedBuffer) {
-    mCachedBuffer = nsStringBuffer::Alloc(bufferSize);
+    mCachedBuffer = nsStringBuffer::Alloc(bufferSize).get();
   }
   NS_ASSERTION(!mCachedBuffer->IsReadonly(),
                "DocumentEncoder shouldn't keep reference to non-readonly buffer!");

layout/style/nsCSSValue.cpp

@@ -624,10 +624,9 @@ nsCSSValue::EqualsFunction(nsCSSKeyword aFunctionId) const
 already_AddRefed<nsStringBuffer>
 nsCSSValue::BufferFromString(const nsString& aValue)
 {
-  nsStringBuffer* buffer = nsStringBuffer::FromString(aValue);
+  nsRefPtr<nsStringBuffer> buffer = nsStringBuffer::FromString(aValue);
   if (buffer) {
-    buffer->AddRef();
-    return buffer;
+    return buffer.forget();
   }
 
   nsString::size_type length = aValue.Length();
@@ -643,7 +642,7 @@ nsCSSValue::BufferFromString(const nsString& aValue)
   nsCharTraits<PRUnichar>::copy(data, aValue.get(), length);
   // Null-terminate.
   data[length] = 0;
-  return buffer;
+  return buffer.forget();
 }
 
 namespace {

parser/html/nsHtml5Atom.cpp

@@ -8,12 +8,10 @@
 nsHtml5Atom::nsHtml5Atom(const nsAString& aString)
 {
   mLength = aString.Length();
-  nsStringBuffer* buf = nsStringBuffer::FromString(aString);
+  nsRefPtr<nsStringBuffer> buf = nsStringBuffer::FromString(aString);
   if (buf) {
-    buf->AddRef();
     mString = static_cast<PRUnichar*>(buf->Data());
-  }
-  else {
+  } else {
     buf = nsStringBuffer::Alloc((mLength + 1) * sizeof(PRUnichar));
     mString = static_cast<PRUnichar*>(buf->Data());
     CopyUnicodeTo(aString, 0, mString, mLength);
@@ -24,6 +22,9 @@ nsHtml5Atom::nsHtml5Atom(const nsAString& aString)
   NS_ASSERTION(buf && buf->StorageSize() >= (mLength+1) * sizeof(PRUnichar),
                "enough storage");
   NS_ASSERTION(Equals(aString), "correct data");
+
+  // Take ownership of buffer
+  buf.forget();
 }
 
 nsHtml5Atom::~nsHtml5Atom()

xpcom/ds/nsAtomTable.cpp

@@ -299,12 +299,10 @@ NS_PurgeAtomTable()
 AtomImpl::AtomImpl(const nsAString& aString, PLDHashNumber aKeyHash)
 {
   mLength = aString.Length();
-  nsStringBuffer* buf = nsStringBuffer::FromString(aString);
+  nsRefPtr<nsStringBuffer> buf = nsStringBuffer::FromString(aString);
   if (buf) {
-    buf->AddRef();
     mString = static_cast<PRUnichar*>(buf->Data());
-  }
-  else {
+  } else {
     buf = nsStringBuffer::Alloc((mLength + 1) * sizeof(PRUnichar));
     mString = static_cast<PRUnichar*>(buf->Data());
     CopyUnicodeTo(aString, 0, mString, mLength);
@@ -319,6 +317,9 @@ AtomImpl::AtomImpl(const nsAString& aString, PLDHashNumber aKeyHash)
   NS_ASSERTION(buf && buf->StorageSize() >= (mLength+1) * sizeof(PRUnichar),
                "enough storage");
   NS_ASSERTION(Equals(aString), "correct data");
+
+  // Take ownership of buffer
+  buf.forget();
 }
 
 AtomImpl::AtomImpl(nsStringBuffer* aStringBuffer, uint32_t aLength,

xpcom/string/public/nsStringBuffer.h

@@ -7,6 +7,7 @@
 #ifndef nsStringBuffer_h__
 #define nsStringBuffer_h__
 
+template<class T> struct already_AddRefed;
 
 /**
  * This structure precedes the string buffers "we" allocate.  It may be the
@@ -41,7 +42,7 @@ class nsStringBuffer
        *
        * @return new string buffer or null if out of memory.
        */
-      static nsStringBuffer* Alloc(size_t storageSize);
+      static already_AddRefed<nsStringBuffer> Alloc(size_t storageSize);
 
       /**
        * Resizes the given string buffer to the specified storage size.  This

xpcom/string/src/nsSubstring.cpp

@@ -21,6 +21,7 @@
 #include "pratom.h"
 #include "prprf.h"
 #include "nsStaticAtom.h"
+#include "nsCOMPtr.h"
 
 // ---------------------------------------------------------------------------
 
@@ -165,7 +166,7 @@ nsStringBuffer::Release()
   /**
    * Alloc returns a pointer to a new string header with set capacity.
    */
-nsStringBuffer*
+already_AddRefed<nsStringBuffer>
 nsStringBuffer::Alloc(size_t size)
   {
     NS_ASSERTION(size != 0, "zero capacity allocation not allowed");
@@ -183,7 +184,7 @@ nsStringBuffer::Alloc(size_t size)
         hdr->mStorageSize = size;
         NS_LOG_ADDREF(hdr, 1, "nsStringBuffer", sizeof(*hdr));
       }
-    return hdr;
+    return dont_AddRef(hdr);
   }
 
 nsStringBuffer*

xpcom/string/src/nsTSubstring.cpp

@@ -127,7 +127,7 @@ nsTSubstring_CharT::MutatePrep( size_type capacity, char_type** oldData, uint32_
         // make use of our F_OWNED or F_FIXED buffers because they are not
         // large enough.
 
-        nsStringBuffer* newHdr = nsStringBuffer::Alloc(storageSize);
+        nsStringBuffer* newHdr = nsStringBuffer::Alloc(storageSize).get();
         if (!newHdr)
           return false; // we are still in a consistent state