From 3fa8c4b046b4b7bf5bf702ac2bbc54c97d326bdd Mon Sep 17 00:00:00 2001
From: Seth Fowler <seth@mozilla.com>
Date: Wed, 10 Sep 2014 17:06:37 -0700
Subject: [PATCH] Bug 1057894 (Part 1) - Make VolatileBufferPtr's moveable.
 r=mwu

---
 memory/mozalloc/VolatileBuffer.h | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/memory/mozalloc/VolatileBuffer.h b/memory/mozalloc/VolatileBuffer.h
index 89e875156efc..0f8a1e6dd13e 100644
--- a/memory/mozalloc/VolatileBuffer.h
+++ b/memory/mozalloc/VolatileBuffer.h
@@ -91,6 +91,7 @@ public:
   }
 
 protected:
+  RefPtr<VolatileBuffer> mVBuf;
   void* mMapping;
 
   void Set(VolatileBuffer* vbuf) {
@@ -100,7 +101,6 @@ protected:
   }
 
 private:
-  RefPtr<VolatileBuffer> mVBuf;
   bool mPurged;
 
   void Lock() {
@@ -126,13 +126,30 @@ public:
   explicit VolatileBufferPtr(VolatileBuffer* vbuf) : VolatileBufferPtr_base(vbuf) {}
   VolatileBufferPtr() : VolatileBufferPtr_base(nullptr) {}
 
+  VolatileBufferPtr(VolatileBufferPtr&& aOther)
+    : VolatileBufferPtr_base(aOther.mVBuf)
+  {
+    aOther.Set(nullptr);
+  }
+
   operator T*() const {
     return (T*) mMapping;
   }
 
-  void operator =(VolatileBuffer* vbuf) {
-    Set(vbuf);
+  VolatileBufferPtr& operator=(VolatileBuffer* aVBuf)
+  {
+    Set(aVBuf);
+    return *this;
   }
+
+  VolatileBufferPtr& operator=(VolatileBufferPtr&& aOther)
+  {
+    MOZ_ASSERT(this != &aOther, "Self-moves are prohibited");
+    Set(aOther.mVBuf);
+    aOther.Set(nullptr);
+    return *this;
+  }
+
 private:
   VolatileBufferPtr(VolatileBufferPtr const& vbufptr) MOZ_DELETE;
 };