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Diffstat (limited to '')
-rw-r--r-- | dependencies/pkg/mod/golang.org/x/sys@v0.1.0/plan9/dir_plan9.go | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/dependencies/pkg/mod/golang.org/x/sys@v0.1.0/plan9/dir_plan9.go b/dependencies/pkg/mod/golang.org/x/sys@v0.1.0/plan9/dir_plan9.go new file mode 100644 index 0000000..0955e0c --- /dev/null +++ b/dependencies/pkg/mod/golang.org/x/sys@v0.1.0/plan9/dir_plan9.go @@ -0,0 +1,212 @@ +// Copyright 2012 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. + +// Plan 9 directory marshalling. See intro(5). + +package plan9 + +import "errors" + +var ( + ErrShortStat = errors.New("stat buffer too short") + ErrBadStat = errors.New("malformed stat buffer") + ErrBadName = errors.New("bad character in file name") +) + +// A Qid represents a 9P server's unique identification for a file. +type Qid struct { + Path uint64 // the file server's unique identification for the file + Vers uint32 // version number for given Path + Type uint8 // the type of the file (plan9.QTDIR for example) +} + +// A Dir contains the metadata for a file. +type Dir struct { + // system-modified data + Type uint16 // server type + Dev uint32 // server subtype + + // file data + Qid Qid // unique id from server + Mode uint32 // permissions + Atime uint32 // last read time + Mtime uint32 // last write time + Length int64 // file length + Name string // last element of path + Uid string // owner name + Gid string // group name + Muid string // last modifier name +} + +var nullDir = Dir{ + Type: ^uint16(0), + Dev: ^uint32(0), + Qid: Qid{ + Path: ^uint64(0), + Vers: ^uint32(0), + Type: ^uint8(0), + }, + Mode: ^uint32(0), + Atime: ^uint32(0), + Mtime: ^uint32(0), + Length: ^int64(0), +} + +// Null assigns special "don't touch" values to members of d to +// avoid modifying them during plan9.Wstat. +func (d *Dir) Null() { *d = nullDir } + +// Marshal encodes a 9P stat message corresponding to d into b +// +// If there isn't enough space in b for a stat message, ErrShortStat is returned. +func (d *Dir) Marshal(b []byte) (n int, err error) { + n = STATFIXLEN + len(d.Name) + len(d.Uid) + len(d.Gid) + len(d.Muid) + if n > len(b) { + return n, ErrShortStat + } + + for _, c := range d.Name { + if c == '/' { + return n, ErrBadName + } + } + + b = pbit16(b, uint16(n)-2) + b = pbit16(b, d.Type) + b = pbit32(b, d.Dev) + b = pbit8(b, d.Qid.Type) + b = pbit32(b, d.Qid.Vers) + b = pbit64(b, d.Qid.Path) + b = pbit32(b, d.Mode) + b = pbit32(b, d.Atime) + b = pbit32(b, d.Mtime) + b = pbit64(b, uint64(d.Length)) + b = pstring(b, d.Name) + b = pstring(b, d.Uid) + b = pstring(b, d.Gid) + b = pstring(b, d.Muid) + + return n, nil +} + +// UnmarshalDir decodes a single 9P stat message from b and returns the resulting Dir. +// +// If b is too small to hold a valid stat message, ErrShortStat is returned. +// +// If the stat message itself is invalid, ErrBadStat is returned. +func UnmarshalDir(b []byte) (*Dir, error) { + if len(b) < STATFIXLEN { + return nil, ErrShortStat + } + size, buf := gbit16(b) + if len(b) != int(size)+2 { + return nil, ErrBadStat + } + b = buf + + var d Dir + d.Type, b = gbit16(b) + d.Dev, b = gbit32(b) + d.Qid.Type, b = gbit8(b) + d.Qid.Vers, b = gbit32(b) + d.Qid.Path, b = gbit64(b) + d.Mode, b = gbit32(b) + d.Atime, b = gbit32(b) + d.Mtime, b = gbit32(b) + + n, b := gbit64(b) + d.Length = int64(n) + + var ok bool + if d.Name, b, ok = gstring(b); !ok { + return nil, ErrBadStat + } + if d.Uid, b, ok = gstring(b); !ok { + return nil, ErrBadStat + } + if d.Gid, b, ok = gstring(b); !ok { + return nil, ErrBadStat + } + if d.Muid, b, ok = gstring(b); !ok { + return nil, ErrBadStat + } + + return &d, nil +} + +// pbit8 copies the 8-bit number v to b and returns the remaining slice of b. +func pbit8(b []byte, v uint8) []byte { + b[0] = byte(v) + return b[1:] +} + +// pbit16 copies the 16-bit number v to b in little-endian order and returns the remaining slice of b. +func pbit16(b []byte, v uint16) []byte { + b[0] = byte(v) + b[1] = byte(v >> 8) + return b[2:] +} + +// pbit32 copies the 32-bit number v to b in little-endian order and returns the remaining slice of b. +func pbit32(b []byte, v uint32) []byte { + b[0] = byte(v) + b[1] = byte(v >> 8) + b[2] = byte(v >> 16) + b[3] = byte(v >> 24) + return b[4:] +} + +// pbit64 copies the 64-bit number v to b in little-endian order and returns the remaining slice of b. +func pbit64(b []byte, v uint64) []byte { + b[0] = byte(v) + b[1] = byte(v >> 8) + b[2] = byte(v >> 16) + b[3] = byte(v >> 24) + b[4] = byte(v >> 32) + b[5] = byte(v >> 40) + b[6] = byte(v >> 48) + b[7] = byte(v >> 56) + return b[8:] +} + +// pstring copies the string s to b, prepending it with a 16-bit length in little-endian order, and +// returning the remaining slice of b.. +func pstring(b []byte, s string) []byte { + b = pbit16(b, uint16(len(s))) + n := copy(b, s) + return b[n:] +} + +// gbit8 reads an 8-bit number from b and returns it with the remaining slice of b. +func gbit8(b []byte) (uint8, []byte) { + return uint8(b[0]), b[1:] +} + +// gbit16 reads a 16-bit number in little-endian order from b and returns it with the remaining slice of b. +func gbit16(b []byte) (uint16, []byte) { + return uint16(b[0]) | uint16(b[1])<<8, b[2:] +} + +// gbit32 reads a 32-bit number in little-endian order from b and returns it with the remaining slice of b. +func gbit32(b []byte) (uint32, []byte) { + return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24, b[4:] +} + +// gbit64 reads a 64-bit number in little-endian order from b and returns it with the remaining slice of b. +func gbit64(b []byte) (uint64, []byte) { + lo := uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24 + hi := uint32(b[4]) | uint32(b[5])<<8 | uint32(b[6])<<16 | uint32(b[7])<<24 + return uint64(lo) | uint64(hi)<<32, b[8:] +} + +// gstring reads a string from b, prefixed with a 16-bit length in little-endian order. +// It returns the string with the remaining slice of b and a boolean. If the length is +// greater than the number of bytes in b, the boolean will be false. +func gstring(b []byte) (string, []byte, bool) { + n, b := gbit16(b) + if int(n) > len(b) { + return "", b, false + } + return string(b[:n]), b[n:], true +} |