Make sure File_WriteFrom write all data unless an error occour

runtime/bin/file.cc

Index: runtime/bin/file.cc
diff --git a/runtime/bin/file.cc b/runtime/bin/file.cc
index c4c417b8603351b6e2526410c3cef8f9d267de06..715f7223f27f1cd0a27a9e6d1bac32153e9bbdc3 100644
--- a/runtime/bin/file.cc
+++ b/runtime/bin/file.cc
@@ -266,16 +266,26 @@ void FUNCTION_NAME(File_WriteFrom)(Dart_NativeArguments args) {
   ASSERT(end <= buffer_len);
   ASSERT(buffer != NULL);
 
-  // Write the data out into the file.
-  int64_t bytes_written = file->Write(buffer, length);
+  // Write all the data out into the file.
+  int64_t remaining = length;
+  while (remaining > 0) {
+    int64_t written = file->Write(buffer, remaining);

[Anders Johnsen, 2015/03/18 10:11:13]

Use file->WriteFully instead?

[Søren Gjesse, 2015/03/19 10:12:44]

Forgot about that. Done.

+    if (written < 0) {
+      break;
+    }
+    remaining -= written;
+    buffer = reinterpret_cast<uint8_t*>(buffer) + written;
+  }
   // Release the direct pointer acquired above.
   result = Dart_TypedDataReleaseData(buffer_obj);
   if (Dart_IsError(result)) Dart_PropagateError(result);
 
-  if (bytes_written != length) {
+  if (remaining > 0) {
     Dart_Handle err = DartUtils::NewDartOSError();
     if (Dart_IsError(err)) Dart_PropagateError(err);
     Dart_SetReturnValue(args, err);
+  } else {
+    Dart_SetReturnValue(args, Dart_Null());
   }
 }