Fixing crash in NS_MsgStripRE() due to multiply-linked strings. b=189591, sr=dbaron, r=me

string/public/nsBufferHandle.h

@@ -180,11 +180,6 @@ struct nsStringAllocatorTraits<PRUnichar>
 // end of string allocator stuff that needs to move
 
 
-
-  /**
-   *
-   * @status FROZEN
-   */
 template <class CharT>
 class nsSharedBufferHandle
     : public nsBufferHandle<CharT>
@@ -192,7 +187,6 @@ class nsSharedBufferHandle
     public:
       typedef PRUint32                          size_type;
 
-    protected:
       enum
         {
           kIsImmutable                    = 0x01000000, // if this is set, the buffer cannot be modified even if its refcount is 1

string/public/nsXPIDLString.h

@@ -188,9 +188,9 @@ class NS_COM nsXPIDLString
         // overridden to make getter_Copies mechanism work
       virtual const char_type* get() const
         {
-          return (mBuffer.get() != GetSharedEmptyBufferHandle())
-                    ? mBuffer->DataStart()
-                    : 0;
+          return (mBuffer->GetImplementationFlags() & shared_buffer_handle_type::kIsNULL)
+                   ? 0
+                   : mBuffer->DataStart();
         }
 
         // deprecated, to be eliminated
@@ -300,9 +300,9 @@ class NS_COM nsXPIDLCString
         // overridden to make getter_Copies mechanism work
       virtual const char_type* get() const
         {
-          return (mBuffer.get() != GetSharedEmptyBufferHandle())
-                    ? mBuffer->DataStart()
-                    : 0;
+          return (mBuffer->GetImplementationFlags() & shared_buffer_handle_type::kIsNULL)
+                   ? 0
+                   : mBuffer->DataStart();
         }
 
         // deprecated, to be eliminated

string/src/nsXPIDLString.cpp

@@ -156,6 +156,7 @@ nsXPIDLString::GetSharedEmptyBufferHandle()
                                          // race to set the refcount, in
                                          // which case we'll pull the
                                          // same trick in |Destroy|.
+      sBufferHandle->SetImplementationFlags(sBufferHandle->GetImplementationFlags() & shared_buffer_handle_type::kIsNULL);
     }
     return sBufferHandle;
   }
@@ -238,6 +239,7 @@ nsXPIDLCString::GetSharedEmptyBufferHandle()
                                          // race to set the refcount, in
                                          // which case we'll pull the
                                          // same trick in |Destroy|.
+      sBufferHandle->SetImplementationFlags(sBufferHandle->GetImplementationFlags() & shared_buffer_handle_type::kIsNULL);
     }
     return sBufferHandle;
   }

xpcom/string/public/nsBufferHandle.h

@@ -180,11 +180,6 @@ struct nsStringAllocatorTraits<PRUnichar>
 // end of string allocator stuff that needs to move
 
 
-
-  /**
-   *
-   * @status FROZEN
-   */
 template <class CharT>
 class nsSharedBufferHandle
     : public nsBufferHandle<CharT>
@@ -192,7 +187,6 @@ class nsSharedBufferHandle
     public:
       typedef PRUint32                          size_type;
 
-    protected:
       enum
         {
           kIsImmutable                    = 0x01000000, // if this is set, the buffer cannot be modified even if its refcount is 1

xpcom/string/public/nsXPIDLString.h

@@ -188,9 +188,9 @@ class NS_COM nsXPIDLString
         // overridden to make getter_Copies mechanism work
       virtual const char_type* get() const
         {
-          return (mBuffer.get() != GetSharedEmptyBufferHandle())
-                    ? mBuffer->DataStart()
-                    : 0;
+          return (mBuffer->GetImplementationFlags() & shared_buffer_handle_type::kIsNULL)
+                   ? 0
+                   : mBuffer->DataStart();
         }
 
         // deprecated, to be eliminated
@@ -300,9 +300,9 @@ class NS_COM nsXPIDLCString
         // overridden to make getter_Copies mechanism work
       virtual const char_type* get() const
         {
-          return (mBuffer.get() != GetSharedEmptyBufferHandle())
-                    ? mBuffer->DataStart()
-                    : 0;
+          return (mBuffer->GetImplementationFlags() & shared_buffer_handle_type::kIsNULL)
+                   ? 0
+                   : mBuffer->DataStart();
         }
 
         // deprecated, to be eliminated

xpcom/string/src/nsXPIDLString.cpp

@@ -156,6 +156,7 @@ nsXPIDLString::GetSharedEmptyBufferHandle()
                                          // race to set the refcount, in
                                          // which case we'll pull the
                                          // same trick in |Destroy|.
+      sBufferHandle->SetImplementationFlags(sBufferHandle->GetImplementationFlags() & shared_buffer_handle_type::kIsNULL);
     }
     return sBufferHandle;
   }
@@ -238,6 +239,7 @@ nsXPIDLCString::GetSharedEmptyBufferHandle()
                                          // race to set the refcount, in
                                          // which case we'll pull the
                                          // same trick in |Destroy|.
+      sBufferHandle->SetImplementationFlags(sBufferHandle->GetImplementationFlags() & shared_buffer_handle_type::kIsNULL);
     }
     return sBufferHandle;
   }