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 88 matching lines @@
     // 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) {
+  struct stat st;
+  if (TEMP_FAILURE_RETRY(stat(name, &st)) == 0) {
+    if (!S_ISREG(st.st_mode)) {
+      errno = (S_ISDIR(st.st_mode)) ? EISDIR : ENOENT;
+      return false;
+    }
+  }
   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) {
     return NULL;
@@ skipping 59 matching lines @@
     do {
       abs_path = realpath(pathname, NULL);
     } while (abs_path == NULL && errno == EINTR);
     ASSERT(abs_path == NULL || IsAbsolutePath(abs_path));
   }
   return abs_path;
 }
 
 
 char* File::GetContainingDirectory(char* pathname) {
+  struct stat st;
+  if (TEMP_FAILURE_RETRY(stat(pathname, &st)) == 0) {
+    if (!S_ISREG(st.st_mode)) {
+      errno = (S_ISDIR(st.st_mode)) ? EISDIR : ENOENT;
+      return NULL;
+    }
+  } else {
+    return NULL;
+  }
   char* path = NULL;
   do {
     path = dirname(pathname);
   } while (path == NULL && errno == EINTR);
   return GetCanonicalPath(path);
 }
 
 
 const char* File::PathSeparator() {
   return "/";
@@ skipping 11 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;
 }