os cleanup.

dir_* and stat_* are just os specific,
not os+arch-specific.

R=r
http://go/go-review/1018010

1 files changed, 77 insertions, 0 deletions

diff --git a/src/pkg/os/dir_linux.go b/src/pkg/os/dir_linux.go
new file mode 100644
index 000000000..d6e77016c
--- /dev/null
+++ b/src/pkg/os/dir_linux.go
@@ -0,0 +1,77 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package os
+
+import (
+	"syscall";
+	"unsafe";
+)
+
+const (
+	blockSize = 4096;	// TODO(r): use statfs
+)
+
+func clen(n []byte) int {
+	for i := 0; i < len(n); i++ {
+		if n[i] == 0 {
+			return i;
+		}
+	}
+	return len(n);
+}
+
+func (file *File) Readdirnames(count int) (names []string, err Error) {
+	// If this file has no dirinfo, create one.
+	if file.dirinfo == nil {
+		file.dirinfo = new(dirInfo);
+		// The buffer must be at least a block long.
+		// TODO(r): use fstatfs to find fs block size.
+		file.dirinfo.buf = make([]byte, blockSize);
+	}
+	d := file.dirinfo;
+	size := count;
+	if size < 0 {
+		size = 100;
+	}
+	names = make([]string, 0, size);	// Empty with room to grow.
+	for count != 0 {
+		// Refill the buffer if necessary
+		if d.bufp >= d.nbuf {
+			var errno int;
+			d.nbuf, errno = syscall.Getdents(file.fd, d.buf);
+			if errno != 0 {
+				return names, NewSyscallError("getdents", errno);
+			}
+			if d.nbuf <= 0 {
+				break;	// EOF
+			}
+			d.bufp = 0;
+		}
+		// Drain the buffer
+		for count != 0 && d.bufp < d.nbuf {
+			dirent := (*syscall.Dirent)(unsafe.Pointer(&d.buf[d.bufp]));
+			d.bufp += int(dirent.Reclen);
+			if dirent.Ino == 0 {	// File absent in directory.
+				continue;
+			}
+			bytes := (*[len(dirent.Name)]byte)(unsafe.Pointer(&dirent.Name[0]));
+			var name = string(bytes[0:clen(bytes)]);
+			if name == "." || name == ".." {	// Useless names
+				continue;
+			}
+			count--;
+			if len(names) == cap(names) {
+				nnames := make([]string, len(names), 2*len(names));
+				for i := 0; i < len(names); i++ {
+					nnames[i] = names[i];
+				}
+				names = nnames;
+			}
+			names = names[0 : len(names)+1];
+			names[len(names)-1] = name;
+		}
+	}
+	return names, nil;
+}