Error reporting on File in dart:io

runtime/bin/file_macos.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "bin/file.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <sys/stat.h>
 #include <unistd.h>
@@ skipping 87 matching lines @@
   if (position < 0) {
     // The file is not capable of seeking. Return an error.
     return -1;
   }
   off_t result = TEMP_FAILURE_RETRY(lseek(handle_->fd(), 0, SEEK_END));
   TEMP_FAILURE_RETRY(lseek(handle_->fd(), position, SEEK_SET));
   return result;
 }
 
 
-File* File::Open(const char* name, FileOpenMode mode) {
+File* File::Open(const char* name, FileOpenMode mode, OSError* os_error) {
   int flags = O_RDONLY;
   if ((mode & kWrite) != 0) {
     flags = (O_RDWR | O_CREAT);
   }
   if ((mode & kTruncate) != 0) {
     flags = flags | O_TRUNC;
   }
   int fd = TEMP_FAILURE_RETRY(open(name, flags, 0666));
   if (fd < 0) {
+    if (os_error != NULL) {
+      os_error->errno_ = errno;
+      os_error->strerror_ = strerror(errno);
+    }
     return NULL;
   }
   if (((mode & kWrite) != 0) && ((mode & kTruncate) == 0)) {
     int position = TEMP_FAILURE_RETRY(lseek(fd, 0, SEEK_END));
     if (position < 0) {
       return NULL;
     }
   }
   return new File(name, new FileHandle(fd));
 }
@@ skipping 81 matching lines @@
   int result = fstat(fd, &buf);
   if (result == -1) {
     FATAL2("Failed stat on file descriptor %d: %s", fd, strerror(errno));
   }
   if (S_ISCHR(buf.st_mode)) return kTerminal;
   if (S_ISFIFO(buf.st_mode)) return kPipe;
   if (S_ISSOCK(buf.st_mode)) return kSocket;
   if (S_ISREG(buf.st_mode)) return kFile;
   return kOther;
 }