Adding some file access utils.

fileutil/fileutil.go

@@ -0,0 +1,47 @@
+// Package fileutil contains common file functions.
+package fileutil
+
+import (
+	"os"
+
+	"golang.org/x/sys/unix"
+)
+
+// FileExistsP returns true if the file exists.
+func FileExistsP(path string) bool {
+	_, err := os.Stat(path)
+	return !os.IsNotExist(err)
+}
+
+// DirectoryExistsP returns true if the file exists.
+func DirectoryExistsP(path string) bool {
+	fi, err := os.Stat(path)
+	if err != nil {
+		return false
+	}
+
+	return fi.Mode().IsDir()
+}
+
+const (
+	// AccessExists checks whether the file exists.
+	AccessExists = unix.F_OK
+
+	// AccessRead checks whether the user has read permissions on
+	// the file.
+	AccessRead = unix.R_OK
+
+	// AccessWrite checks whether the user has write permissions
+	// on the file.
+	AccessWrite = unix.W_OK
+
+	// AccessExec checks whether the user has executable
+	// permissions on the file.
+	AccessExec = unix.X_OK
+)
+
+// Access returns a boolean indicating whether the mode being checked
+// for is valid.
+func Access(path string, mode int) error {
+	return unix.Access(path, uint32(mode))
+}