Bug 410131 - DM isn't buffering writes when saving a file. r=biesi, sr=bz

embedding/components/webbrowserpersist/src/nsWebBrowserPersist.cpp

@@ -121,6 +121,8 @@
 
 #include "nsWebBrowserPersist.h"
 
+// Buffer file writes in 32kb chunks
+#define BUFFERED_OUTPUT_SIZE (1024 * 32)
 
 #define NS_SUCCESS_DONT_FIXUP NS_ERROR_GENERATE_SUCCESS(NS_ERROR_MODULE_GENERAL, 1)
 
@@ -2281,7 +2283,8 @@ nsWebBrowserPersist::MakeOutputStreamFromFile(
     rv = fileOutputStream->Init(aFile, ioFlags, -1, 0);
     NS_ENSURE_SUCCESS(rv, rv);
 
-    NS_ENSURE_SUCCESS(CallQueryInterface(fileOutputStream, aOutputStream), NS_ERROR_FAILURE);
+    *aOutputStream = NS_BufferOutputStream(fileOutputStream,
+                                           BUFFERED_OUTPUT_SIZE).get();
 
     if (mPersistFlags & PERSIST_FLAGS_CLEANUP_ON_FAILURE)
     {

netwerk/base/public/nsNetUtil.h

@@ -947,6 +947,33 @@ NS_NewBufferedOutputStream(nsIOutputStream **result,
     return rv;
 }
 
+/**
+ * Attempts to buffer a given output stream.  If this fails, it returns the
+ * passed-in output stream.
+ *
+ * @param aOutputStream
+ *        The output stream we want to buffer.  This cannot be null.
+ * @param aBufferSize
+ *        The size of the buffer for the buffered output stream.
+ * @returns an nsIOutputStream that is buffered with the specified buffer size,
+ *          or is aOutputStream if creating the new buffered stream failed.
+ */
+inline already_AddRefed<nsIOutputStream>
+NS_BufferOutputStream(nsIOutputStream *aOutputStream,
+                      PRUint32 aBufferSize)
+{
+    NS_ASSERTION(aOutputStream, "No output stream given!");
+
+    nsCOMPtr<nsIOutputStream> bos;
+    nsresult rv = NS_NewBufferedOutputStream(getter_AddRefs(bos), aOutputStream,
+                                             aBufferSize);
+    if (NS_SUCCEEDED(rv))
+        return bos.forget();
+
+    NS_ADDREF(aOutputStream);
+    return aOutputStream;
+}
+
 // returns an input stream compatible with nsIUploadChannel::SetUploadStream()
 inline nsresult
 NS_NewPostDataStream(nsIInputStream  **result,

uriloader/exthandler/nsExternalHelperAppService.cpp

@@ -124,6 +124,9 @@
 #include "plbase64.h"
 #include "prmem.h"
 
+// Buffer file writes in 32kb chunks
+#define BUFFERED_OUTPUT_SIZE (1024 * 32)
+
 #ifdef PR_LOGGING
 PRLogModuleInfo* nsExternalHelperAppService::mLog = nsnull;
 #endif
@@ -1240,13 +1243,16 @@ nsresult nsExternalAppHandler::SetUpTempFile(nsIChannel * aChannel)
   }
 #endif
 
-  rv = NS_NewLocalFileOutputStream(getter_AddRefs(mOutStream), mTempFile,
+  nsCOMPtr<nsIOutputStream> outputStream;
+  rv = NS_NewLocalFileOutputStream(getter_AddRefs(outputStream), mTempFile,
                                    PR_WRONLY | PR_CREATE_FILE, 0600);
   if (NS_FAILED(rv)) {
     mTempFile->Remove(PR_FALSE);
     return rv;
   }
 
+  mOutStream = NS_BufferOutputStream(outputStream, BUFFERED_OUTPUT_SIZE);
+
 #ifdef XP_MACOSX
     nsCAutoString contentType;
     mMimeInfo->GetMIMEType(contentType);
@@ -1995,8 +2001,10 @@ NS_IMETHODIMP nsExternalAppHandler::SaveToDisk(nsIFile * aNewFileLocation, PRBoo
       rv = mTempFile->MoveTo(dir, name);
       if (NS_SUCCEEDED(rv)) // if it failed, we just continue with $TEMP
         mTempFile = movedFile;
-      rv = NS_NewLocalFileOutputStream(getter_AddRefs(mOutStream), mTempFile,
-                                         PR_WRONLY | PR_APPEND, 0600);
+
+      nsCOMPtr<nsIOutputStream> outputStream;
+      rv = NS_NewLocalFileOutputStream(getter_AddRefs(outputStream), mTempFile,
+                                       PR_WRONLY | PR_APPEND, 0600);
       if (NS_FAILED(rv)) { // (Re-)opening the output stream failed. bad luck.
         nsAutoString path;
         mTempFile->GetPath(path);
@@ -2004,6 +2012,8 @@ NS_IMETHODIMP nsExternalAppHandler::SaveToDisk(nsIFile * aNewFileLocation, PRBoo
         Cancel(rv);
         return NS_OK;
       }
+
+      mOutStream = NS_BufferOutputStream(outputStream, BUFFERED_OUTPUT_SIZE);
     }
   }