[Development] os: introduce new function called "fileexists"


git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@4255 3789f03b-4d11-0410-bbf8-ca57d06f2519
diff --git a/common/os/os.cxx b/common/os/os.cxx
index c08b572..46470ea 100644
--- a/common/os/os.cxx
+++ b/common/os/os.cxx
@@ -85,3 +85,13 @@
 	return 0;
 }
 
+int fileexists(char *file)
+{
+#ifdef WIN32
+  return (GetFileAttributes(file) == INVALID_FILE_ATTRIBUTES) ? -1 : 0;
+#else
+  return access(file, R_OK);
+#endif
+}
+
+
diff --git a/common/os/os.h b/common/os/os.h
index d011764..1847a49 100644
--- a/common/os/os.h
+++ b/common/os/os.h
@@ -37,4 +37,13 @@
  */
 int getvnchomedir(char **dirp);
 
+/*
+ * Check if the file exists
+ *
+ * Returns:
+ * 0 - Success
+ * -1 - Failure
+ */
+int fileexists(char *file);
+
 #endif /* OS_OS_H */