Bug 814376 - Improve the mechanism for setting file extension of a blob, r=sicking

dom/bluetooth/BluetoothOppManager.cpp

@@ -17,13 +17,14 @@
 #include "mozilla/RefPtr.h"
 #include "mozilla/Services.h"
 #include "mozilla/StaticPtr.h"
+#include "nsCExternalHandlerService.h"
 #include "nsIObserver.h"
 #include "nsIObserverService.h"
 #include "nsIDOMFile.h"
 #include "nsIFile.h"
 #include "nsIInputStream.h"
+#include "nsIMIMEService.h"
 #include "nsIOutputStream.h"
-#include "nsLocalFile.h"
 #include "nsNetUtil.h"
 
 #define TARGET_FOLDER "/sdcard/downloads/bluetooth/"
@@ -283,22 +284,48 @@ BluetoothOppManager::SendFile(BlobParent* aActor)
    */
   mBlob = aActor->GetBlob();
 
-  nsCOMPtr<nsIDOMFile> domFile = do_QueryInterface(mBlob);
-  nsString fullPath;
+  sFileName.Truncate();
 
-  if (domFile && NS_SUCCEEDED(domFile->GetMozFullPathInternal(fullPath))) {
-    nsCOMPtr<nsIFile> localFile = new nsLocalFile();
-    NS_NewLocalFile(fullPath, false, getter_AddRefs(localFile));
-
-    if (localFile) {
-      localFile->GetLeafName(sFileName);
-    }
+  nsCOMPtr<nsIDOMFile> file = do_QueryInterface(mBlob);
+  if (file) {
+    file->GetName(sFileName);
   }
 
+  /**
+   * We try our best to get the file extention to avoid interoperability issues.
+   * However, once we found that we are unable to get suitable extension or
+   * information about the content type, sending a pre-defined file name without
+   * extension would be fine.
+   */
   if (sFileName.IsEmpty()) {
     sFileName.AssignLiteral("Unknown");
   }
 
+  int32_t offset = sFileName.RFindChar('/');
+  if (offset != kNotFound) {
+    sFileName = Substring(sFileName, offset + 1);
+  }
+
+  offset = sFileName.RFindChar('.');
+  if (offset == kNotFound) {
+    nsCOMPtr<nsIMIMEService> mimeSvc = do_GetService(NS_MIMESERVICE_CONTRACTID);
+
+    if (mimeSvc) {
+      nsString mimeType;
+      mBlob->GetType(mimeType);
+
+      nsCString extension;
+      nsresult rv =
+        mimeSvc->GetPrimaryExtension(NS_LossyConvertUTF16toASCII(mimeType),
+                                     EmptyCString(),
+                                     extension);
+      if (NS_SUCCEEDED(rv)) {
+        sFileName.AppendLiteral(".");
+        AppendUTF8toUTF16(extension, sFileName);
+      }
+    }
+  }
+
   SendConnectRequest();
 
   return true;