Add Directory.createTemp() to asynchronously create a temporary directory.

runtime/bin/directory_posix.cc

 // Copyright (c) 2011, 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/directory.h"
 
 #include <dirent.h>
 #include <errno.h>
 #include <sys/param.h>
 #include <sys/stat.h>
@@ skipping 235 matching lines @@
 }
 
 
 bool Directory::Create(const char* dir_name) {
   // Create the directory with the permissions specified by the
   // process umask.
   return (mkdir(dir_name, 0777) == 0);
 }
 
 
+char* Directory::CreateTemp(const char* const_template) {
+  // Returns a new, unused directory name, modifying the contents of
+  // dir_template.  Creates this directory, with mode ???.

[Mads Ager (google), 2011/11/18 09:50:45]

Update comment with the actual mode.

[Bill Hesse, 2011/11/21 15:48:41]

Done.

+  // The return value must be freed by the caller.
+  char* path = static_cast<char*>(malloc(PATH_MAX + 1));
+  strncpy(path, const_template, PATH_MAX + 1);
+  path[PATH_MAX] = '\0';
+  char* result = mkdtemp(path);
+  if (result == NULL) {
+    // Return the empty string, but as a freeable array.
+    path[0] = '\0';
+  }
+  return path;
+}
+
+
 bool Directory::Delete(const char* dir_name) {
   return (rmdir(dir_name) == 0);
 }