1 files changed, 63 insertions, 0 deletions
diff --git a/weed-fs/src/pkg/util/file.go b/weed-fs/src/pkg/util/file.go
new file mode 100644
index 000000000..bf3ea66de
--- /dev/null
+++ b/weed-fs/src/pkg/util/file.go
@@ -0,0 +1,63 @@
+package util
+
+import (
+	"errors"
+	"log"
+	"os"
+)
+
+// sets file (fh if not nil, otherwise fileName) permission to mask
+// it will
+//   AND with the permission iff direction < 0
+//   OR with the permission iff direction > 0
+//   otherwise it will SET the permission to the mask
+func SetFilePerm(fh *os.File, fileName string, mask os.FileMode, direction int8) (err error) {
+	var stat os.FileInfo
+	if fh == nil {
+		stat, err = os.Stat(fileName)
+	} else {
+		stat, err = fh.Stat()
+	}
+	if err != nil {
+		return err
+	}
+
+	mode := stat.Mode() & ^os.ModePerm
+	// log.Printf("mode1=%d mask=%d", mode, mask)
+	if direction == 0 {
+		mode |= mask
+	} else if direction > 0 {
+		mode |= stat.Mode().Perm() | mask
+	} else {
+		mode |= stat.Mode().Perm() & mask
+	}
+	log.Printf("pmode=%d operm=%d => nmode=%d nperm=%d",
+		stat.Mode(), stat.Mode()&os.ModePerm,
+		mode, mode&os.ModePerm)
+	if mode == 0 {
+		return errors.New("Zero FileMode")
+	}
+	if fh == nil {
+		err = os.Chmod(fileName, mode)
+	} else {
+		err = fh.Chmod(mode)
+	}
+	return err
+}
+
+// returns whether  the filename exists - errors doesn't mean not exists!
+func FileExists(fileName string) bool {
+	if _, e := os.Stat(fileName); e != nil && os.IsNotExist(e) {
+		return false
+	}
+	return true
+}
+
+// returns whether the filename is POSSIBLY writable
+//- whether it has some kind of writable bit set
+func FileIsWritable(fileName string) bool {
+	if stat, e := os.Stat(fileName); e == nil {
+		return stat.Mode().Perm()&0222 > 0
+	}
+	return false
+}