Bug 1249389 - part 1 - change NewObjectInputStreamFromBuffer to take a UniquePtr argument; r=erahm

Because NewObjectInputStreamFromBuffer takes a raw pointer as input, the
typical coding pattern to use it is:

  nsAutoArrayPtr<char> buf;
  // assign something to buf
  nsresult rv = NewObjectInputStreamFromBuffer(buf, ...);
  if (NS_FAILED(rv)) {
    ...
    return rv;
  }
  buf.forget();

Which is clumsy, error-prone, and obscures the ownership transfer of the
pointer into the stream returned by NewObjectInputStreamFromBuffer.
Let's address all of these concerns by changing the argument to a
UniquePtr<char[]>.

dom/xbl/nsXBLDocumentInfo.cpp

@@ -206,9 +206,9 @@ nsXBLDocumentInfo::ReadPrototypeBindings(nsIURI* aURI, nsXBLDocumentInfo** aDocI
     return rv;
 
   nsCOMPtr<nsIObjectInputStream> stream;
-  rv = NewObjectInputStreamFromBuffer(buf, len, getter_AddRefs(stream));
+  rv = NewObjectInputStreamFromBuffer(UniquePtr<char[]>(buf.forget()),
+                                      len, getter_AddRefs(stream));
   NS_ENSURE_SUCCESS(rv, rv);
-  buf.forget();
 
   // The file compatibility.ini stores the build id. This is checked in
   // nsAppRunner.cpp and will delete the cache if a different build is

dom/xul/nsXULPrototypeCache.cpp

@@ -345,9 +345,9 @@ nsXULPrototypeCache::GetInputStream(nsIURI* uri, nsIObjectInputStream** stream)
     if (NS_FAILED(rv))
         return NS_ERROR_NOT_AVAILABLE;
 
-    rv = NewObjectInputStreamFromBuffer(buf, len, getter_AddRefs(ois));
+    rv = NewObjectInputStreamFromBuffer(UniquePtr<char[]>(buf.forget()),
+                                        len, getter_AddRefs(ois));
     NS_ENSURE_SUCCESS(rv, rv);
-    buf.forget();
 
     mInputStreamTable.Put(uri, ois);
 
@@ -500,10 +500,10 @@ nsXULPrototypeCache::BeginCaching(nsIURI* aURI)
     rv = startupCache->GetBuffer(kXULCacheInfoKey, getter_Transfers(buf),
                                  &len);
     if (NS_SUCCEEDED(rv))
-        rv = NewObjectInputStreamFromBuffer(buf, len, getter_AddRefs(objectInput));
+        rv = NewObjectInputStreamFromBuffer(UniquePtr<char[]>(buf.forget()),
+                                            len, getter_AddRefs(objectInput));
 
     if (NS_SUCCEEDED(rv)) {
-        buf.forget();
         rv = objectInput->ReadCString(fileLocale);
         tmp = objectInput->ReadCString(fileChromePath);
         if (NS_FAILED(tmp)) {

startupcache/StartupCacheUtils.cpp

@@ -19,7 +19,7 @@ namespace mozilla {
 namespace scache {
 
 NS_EXPORT nsresult
-NewObjectInputStreamFromBuffer(char* buffer, uint32_t len, 
+NewObjectInputStreamFromBuffer(UniquePtr<char[]> buffer, uint32_t len, 
                                nsIObjectInputStream** stream)
 {
   nsCOMPtr<nsIStringInputStream> stringStream
@@ -27,7 +27,7 @@ NewObjectInputStreamFromBuffer(char* buffer, uint32_t len,
   nsCOMPtr<nsIObjectInputStream> objectInput 
     = do_CreateInstance("@mozilla.org/binaryinputstream;1");
   
-  stringStream->AdoptData(buffer, len);
+  stringStream->AdoptData(buffer.release(), len);
   objectInput->SetInputStream(stringStream);
   
   objectInput.forget(stream);

startupcache/StartupCacheUtils.h

@@ -8,12 +8,13 @@
 #include "nsIStorageStream.h"
 #include "nsIObjectInputStream.h"
 #include "nsIObjectOutputStream.h"
+#include "mozilla/UniquePtr.h"
 
 namespace mozilla {
 namespace scache {
 
 NS_EXPORT nsresult
-NewObjectInputStreamFromBuffer(char* buffer, uint32_t len, 
+NewObjectInputStreamFromBuffer(UniquePtr<char[]> buffer, uint32_t len, 
                                nsIObjectInputStream** stream);
 
 // We can't retrieve the wrapped stream from the objectOutputStream later,

startupcache/test/TestStartupCache.cpp

@@ -23,6 +23,7 @@
 #include "nsIXPConnect.h"
 #include "prio.h"
 #include "mozilla/Maybe.h"
+#include "mozilla/UniquePtr.h"
 
 using namespace JS;
 
@@ -30,7 +31,7 @@ namespace mozilla {
 namespace scache {
 
 NS_IMPORT nsresult
-NewObjectInputStreamFromBuffer(char* buffer, uint32_t len, 
+NewObjectInputStreamFromBuffer(UniquePtr<char[]> buffer, uint32_t len, 
                                nsIObjectInputStream** stream);
 
 // We can't retrieve the wrapped stream from the objectOutputStream later,
@@ -46,6 +47,7 @@ NewBufferFromStorageStream(nsIStorageStream *storageStream,
 } // namespace mozilla
 
 using namespace mozilla::scache;
+using mozilla::UniquePtr;
 
 #define NS_ENSURE_STR_MATCH(str1, str2, testname)  \
 PR_BEGIN_MACRO                                     \
@@ -216,12 +218,12 @@ TestWriteObject() {
     return rv;
   }
 
-  rv = NewObjectInputStreamFromBuffer(buf2, len2, getter_AddRefs(objectInput));
+  rv = NewObjectInputStreamFromBuffer(UniquePtr<char[]>(buf2.forget()), len2,
+                                      getter_AddRefs(objectInput));
   if (NS_FAILED(rv)) {
     fail("failed to created input stream");
     return rv;
   }  
-  buf2.forget();
 
   nsCOMPtr<nsISupports> deserialized;
   rv = objectInput->ReadObject(true, getter_AddRefs(deserialized));