diff options
Diffstat (limited to 'vendor/golang.org/x/tools/internal/fastwalk/fastwalk_unix.go')
-rw-r--r-- | vendor/golang.org/x/tools/internal/fastwalk/fastwalk_unix.go | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/vendor/golang.org/x/tools/internal/fastwalk/fastwalk_unix.go b/vendor/golang.org/x/tools/internal/fastwalk/fastwalk_unix.go new file mode 100644 index 00000000..67db6caf --- /dev/null +++ b/vendor/golang.org/x/tools/internal/fastwalk/fastwalk_unix.go @@ -0,0 +1,123 @@ +// Copyright 2016 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. + +// +build linux darwin freebsd openbsd netbsd +// +build !appengine + +package fastwalk + +import ( + "bytes" + "fmt" + "os" + "syscall" + "unsafe" +) + +const blockSize = 8 << 10 + +// unknownFileMode is a sentinel (and bogus) os.FileMode +// value used to represent a syscall.DT_UNKNOWN Dirent.Type. +const unknownFileMode os.FileMode = os.ModeNamedPipe | os.ModeSocket | os.ModeDevice + +func readDir(dirName string, fn func(dirName, entName string, typ os.FileMode) error) error { + fd, err := syscall.Open(dirName, 0, 0) + if err != nil { + return &os.PathError{Op: "open", Path: dirName, Err: err} + } + defer syscall.Close(fd) + + // The buffer must be at least a block long. + buf := make([]byte, blockSize) // stack-allocated; doesn't escape + bufp := 0 // starting read position in buf + nbuf := 0 // end valid data in buf + for { + if bufp >= nbuf { + bufp = 0 + nbuf, err = syscall.ReadDirent(fd, buf) + if err != nil { + return os.NewSyscallError("readdirent", err) + } + if nbuf <= 0 { + return nil + } + } + consumed, name, typ := parseDirEnt(buf[bufp:nbuf]) + bufp += consumed + if name == "" || name == "." || name == ".." { + continue + } + // Fallback for filesystems (like old XFS) that don't + // support Dirent.Type and have DT_UNKNOWN (0) there + // instead. + if typ == unknownFileMode { + fi, err := os.Lstat(dirName + "/" + name) + if err != nil { + // It got deleted in the meantime. + if os.IsNotExist(err) { + continue + } + return err + } + typ = fi.Mode() & os.ModeType + } + if err := fn(dirName, name, typ); err != nil { + return err + } + } +} + +func parseDirEnt(buf []byte) (consumed int, name string, typ os.FileMode) { + // golang.org/issue/15653 + dirent := (*syscall.Dirent)(unsafe.Pointer(&buf[0])) + if v := unsafe.Offsetof(dirent.Reclen) + unsafe.Sizeof(dirent.Reclen); uintptr(len(buf)) < v { + panic(fmt.Sprintf("buf size of %d smaller than dirent header size %d", len(buf), v)) + } + if len(buf) < int(dirent.Reclen) { + panic(fmt.Sprintf("buf size %d < record length %d", len(buf), dirent.Reclen)) + } + consumed = int(dirent.Reclen) + if direntInode(dirent) == 0 { // File absent in directory. + return + } + switch dirent.Type { + case syscall.DT_REG: + typ = 0 + case syscall.DT_DIR: + typ = os.ModeDir + case syscall.DT_LNK: + typ = os.ModeSymlink + case syscall.DT_BLK: + typ = os.ModeDevice + case syscall.DT_FIFO: + typ = os.ModeNamedPipe + case syscall.DT_SOCK: + typ = os.ModeSocket + case syscall.DT_UNKNOWN: + typ = unknownFileMode + default: + // Skip weird things. + // It's probably a DT_WHT (http://lwn.net/Articles/325369/) + // or something. Revisit if/when this package is moved outside + // of goimports. goimports only cares about regular files, + // symlinks, and directories. + return + } + + nameBuf := (*[unsafe.Sizeof(dirent.Name)]byte)(unsafe.Pointer(&dirent.Name[0])) + nameLen := bytes.IndexByte(nameBuf[:], 0) + if nameLen < 0 { + panic("failed to find terminating 0 byte in dirent") + } + + // Special cases for common things: + if nameLen == 1 && nameBuf[0] == '.' { + name = "." + } else if nameLen == 2 && nameBuf[0] == '.' && nameBuf[1] == '.' { + name = ".." + } else { + name = string(nameBuf[:nameLen]) + } + return +} |