func (g *GraphTool) tarCp(srcName string, tw *tar.Writer) (int64, error) {
var (
src *os.File
err error
)
if src, err = os.Open(srcName); err != nil {
return 0, err
}
defer src.Close()
srcStat, err := src.Stat()
if err != nil {
g.logger.Error(err.Error())
} else if err := unix.Fadvise(int(src.Fd()), 0, srcStat.Size(), unix.MADV_SEQUENTIAL); err != nil {
g.logger.Error(err.Error())
}
if n, err := io.Copy(tw, src); err != nil {
g.logger.Error(err.Error())
} else {
return n, nil
}
return 0, nil
}
// ClearCache syncs and then removes the file's content from the OS cache.
func ClearCache(file File) error {
f, ok := file.(*os.File)
if !ok {
panic("ClearCache called for file not *os.File")
}
err := f.Sync()
if err != nil {
return err
}
return unix.Fadvise(int(f.Fd()), 0, 0, _POSIX_FADV_DONTNEED)
}
func (f *nonCachingFile) Read(p []byte) (int, error) {
n, err := f.File.Read(p)
if n > 0 {
ferr := unix.Fadvise(int(f.File.Fd()), f.readOffset, int64(n), _POSIX_FADV_DONTNEED)
f.readOffset += int64(n)
if err == nil {
err = ferr
}
}
return n, err
}
func main() {
var ok int // return status
outStat, err := os.Stdout.Stat()
if err != nil {
fatal.Fatalln(err)
}
outReg := outStat.Mode().IsRegular()
outBsize := bsize(outStat)
// catch (./cat) < /etc/group
args := flag.Args()
if flag.NArg() == 0 {
args = []string{"-"}
}
var file *os.File
for _, arg := range args {
file = os.Stdin
if arg != "-" {
file, err = os.Open(arg)
if err != nil {
fatal.Fatalln(err)
}
}
inStat, err := file.Stat()
if err != nil {
fatal.Fatalln(err)
}
if inStat.IsDir() {
fatal.Printf("%s: is a directory\n", file.Name())
}
inBsize := bsize(inStat)
// prefetch! prefetch! prefetch!
unix.Fadvise(int(file.Fd()), 0, 0, unix.FADV_SEQUENTIAL)
// Make sure we're not catting a file to itself,
// provided it's a regular file. Catting a non-reg
// file to itself is cool.
// e.g. cat file > file
if outReg && os.SameFile(outStat, inStat) {
if n, _ := file.Seek(0, os.SEEK_CUR); n < inStat.Size() {
fatal.Fatalf("%s: input file is output file\n", file.Name())
}
}
pageSize := os.Getpagesize()
if simple {
// Select larger block size
size := max(inBsize, outBsize)
outBuf := bufio.NewWriterSize(os.Stdout, size+pageSize-1)
ok ^= simpleCat(file, outBuf)
// Flush because we don't have a chance to in
// simpleCat() because we use io.Copy()
outBuf.Flush()
} else {
// If you want to know why, exactly, I chose
// outBsize -1 + inBsize*4 + 20, read GNU's cat
// source code. The tl;dr is the 20 is the counter
// buffer, inBsize*4 is from potentially prepending
// the control characters (M-^), and outBsize is
// due to new tests for newlines.
size := outBsize - 1 + inBsize*4 + 20
outBuf := bufio.NewWriterSize(os.Stdout, size)
inBuf := make([]byte, inBsize+pageSize-1)
ok ^= cat(file, inBuf, outBuf)
}
file.Close()
}
os.Exit(ok)
}
func wc(file *os.File, cur int64, status fstatus) int {
// Our temp number of lines, words, chars, and bytes
var (
lines int64
words int64
chars int64
numBytes int64
lineLength int64
buffer [bufferSize]byte
// Return value.
ok = 0
)
countComplicated := *printWords || *printLineLength
if !*printBytes || *printChars || *printLines || countComplicated {
unix.Fadvise(int(file.Fd()), 0, 0, unix.FADV_SEQUENTIAL)
}
// If we simply want the bytes we can ignore the overhead of
// counting lines, chars, and words
if *printBytes && !*printChars && !*printLines && !countComplicated {
if status.failed != nil {
status.stat, status.failed = file.Stat()
}
// For sized files, seek a block from EOF.
// From GNU's source:
//
// "This works better for files in proc-like file systems where
// the size is only approximate."
if status.failed == nil &&
// Regular file but not stdin.
((status.stat.Mode().IsRegular() &&
status.stat.Mode()&os.ModeCharDevice != 0) ||
status.stat.Mode()&os.ModeSymlink != 0) &&
0 < status.stat.Size() {
numBytes = status.stat.Size()
end := numBytes
high := end - end%(blockSize+1)
if cur < 0 {
cur, _ = file.Seek(0, os.SEEK_CUR)
}
if 0 <= cur && cur < high {
if n, _ := file.Seek(high, os.SEEK_CUR); 0 <= n {
numBytes = high - cur
}
}
}
unix.Fadvise(int(file.Fd()), 0, 0, unix.FADV_SEQUENTIAL)
for {
n, err := file.Read(buffer[:])
if err != nil {
if err != io.EOF {
ok = 1
}
break
}
numBytes += int64(n)
}
// Use a different loop to lower overhead if we're *only* counting
// lines (or lines and bytes)
} else if !*printChars && !countComplicated {
for {
n, err := file.Read(buffer[:])
if err != nil {
if err != io.EOF {
ok = 1
}
break
}
// Go doesn't inline this sooo...
for i := 0; i < n; i++ {
if buffer[i] != '\n' {
o := bytes.IndexByte(buffer[i:n], '\n')
if o < 0 {
break
}
i += o
}
lines++
}
numBytes += int64(n)
}
} else {
var (
inWord int64
linePos int64
)
for {
n, err := file.Read(buffer[:])
if err != nil {
if err != io.EOF {
ok = 1
}
break
}
numBytes += int64(n)
for bp := 0; bp < n; {
r, s := utf8.DecodeRune(buffer[bp:])
switch r {
case '\n':
lines++
fallthrough
case '\r':
fallthrough
case '\f':
if linePos > lineLength {
lineLength = linePos
}
linePos = 0
words += inWord
inWord = 0
case '\t':
linePos += *tabWidth - (linePos % *tabWidth)
words += inWord
inWord = 0
case ' ':
linePos++
fallthrough
case '\v':
words += inWord
inWord = 0
default:
if unicode.IsPrint(r) {
linePos++
if unicode.IsSpace(r) {
words += inWord
inWord = 0
}
inWord = 1
}
}
chars++
bp += s
}
}
if linePos > lineLength {
lineLength = linePos
}
words += inWord
}
writeCounts(lines, words, chars, numBytes, lineLength, file.Name())
totalBytes += numBytes
totalChars += chars
totalLines += lines
totalWords += words
if lineLength > maxLineLength {
maxLineLength = lineLength
}
return ok
}
func wc(file *os.File, cur int64, status *fstatus) int {
// Our temp number of lines, words, chars, and bytes
var (
lines int64
words int64
chars int64
numBytes int64
lineLength int64
linePos int64
inWord int64
buffer = make([]byte, BufferSize+1)
// Return value.
ok = 0
)
countComplicated := *printWords || *printLineLength
if !*printBytes || *printChars || *printLines || countComplicated {
unix.Fadvise(int(file.Fd()), 0, 0, unix.FADV_SEQUENTIAL)
}
// If we simply want the bytes we can ignore the overhead of
// counting lines, chars, and words
if *printBytes && !*printChars && !*printLines && !countComplicated {
// Manually count bytes if Stat() failed or if we're reading from
// piped input (e.g. cat file.csv | wc -c -)
if status.stat == nil || status.stat.Mode()&os.ModeNamedPipe != 0 {
unix.Fadvise(int(file.Fd()), 0, 0, unix.FADV_SEQUENTIAL)
for {
n, err := file.Read(buffer)
if err != nil && err != io.EOF {
ok = 1
break
}
numBytes += int64(n)
if err == io.EOF {
break
}
}
} else {
numBytes = status.stat.Size()
end := numBytes
high := end - end%BufferSize
if cur <= 0 {
cur, _ = file.Seek(0, os.SEEK_CUR)
}
if 0 <= cur && cur < high {
if n, _ := file.Seek(high, os.SEEK_CUR); 0 <= n {
numBytes = high - cur
}
}
}
// Use a different loop to lower overhead if we're *only* counting
// lines (or lines and bytes)
} else if !*printChars && !countComplicated {
for {
n, err := file.Read(buffer)
if err != nil && err != io.EOF {
ok = 1
break
}
lines += count(buffer[:n], NewLineByte)
numBytes += int64(n)
if err == io.EOF {
break
}
}
} else {
for {
n, err := file.Read(buffer)
numBytes += int64(n)
b := buffer[:n]
for len(b) > 0 {
r, s := utf8.DecodeRune(b)
switch r {
case NewLine:
lines++
fallthrough
case Return:
fallthrough
case FormFeed:
if linePos > lineLength {
lineLength = linePos
}
linePos = 0
words += inWord
inWord = 0
case HorizTab:
linePos += *tabWidth - (linePos % *tabWidth)
words += inWord
inWord = 0
case Space:
linePos++
fallthrough
case VertTab:
words += inWord
inWord = 0
default:
if unicode.IsPrint(r) {
linePos++
inWord = 1
}
}
chars++
b = b[s:]
}
if err == io.EOF {
break
} else if err != nil {
ok = 1
break
}
}
if linePos > lineLength {
lineLength = linePos
}
words += inWord
}
writeCounts(lines, words, chars, numBytes, lineLength, file.Name())
totalBytes += numBytes
totalChars += chars
totalLines += lines
totalWords += words
if lineLength > maxLineLength {
maxLineLength = lineLength
}
return ok
}
func main() {
flag.Usage = func() {
fmt.Fprintf(os.Stderr, "%s", Help)
os.Exit(1)
}
flag.Parse()
if *version {
fmt.Fprintf(os.Stdout, "%s", Version)
os.Exit(0)
}
var (
ok int // return status
simple bool // no non-printing
)
// -vET
if *all {
*nonPrint = true
*npTabs = true
*npEnds = true
}
if *npEnds {
*ends = true
}
if *blank {
*number = true
}
if *npTabs {
*tabs = true
}
if *all || *npEnds || *npTabs || *nonPrint {
showNonPrinting = true
}
outStat, err := os.Stdout.Stat()
if err != nil {
fatal.Fatalln(err)
}
outReg := outStat.Mode().IsRegular()
outBsize := int(outStat.Sys().(*syscall.Stat_t).Blksize)
// catch (./cat) < /etc/group
var args []string
if flag.NArg() == 0 {
args = []string{"-"}
} else {
args = flag.Args()
}
// the main loop
var file *os.File
for _, arg := range args {
if arg == "-" {
file = os.Stdin
} else {
file, err = os.Open(arg)
if err != nil {
fatal.Fatalln(err)
}
}
inStat, err := file.Stat()
if err != nil {
fatal.Fatalln(err)
}
if inStat.IsDir() {
fatal.Printf("%s: Is a directory\n", file.Name())
}
inBsize := int(inStat.Sys().(*syscall.Stat_t).Blksize)
// prefetch! prefetch! prefetch!
unix.Fadvise(int(file.Fd()), 0, 0, unix.FADV_SEQUENTIAL)
// Make sure we're not catting a file to itself,
// provided it's a regular file. Catting a non-reg
// file to itself is cool.
// e.g. cat file > file
if outReg && os.SameFile(outStat, inStat) {
if n, _ := file.Seek(0, os.SEEK_CUR); n < inStat.Size() {
fatal.Fatalf("%s: input file is output file\n", file.Name())
}
}
if simple {
// Select larger block size
size := max(inBsize, outBsize)
outBuf := bufio.NewWriterSize(os.Stdout, size)
ok ^= simpleCat(file, outBuf)
// Flush because we don't have a chance to in
// simpleCat() because we use io.Copy()
outBuf.Flush()
} else {
// If you want to know why, exactly, I chose
// outBsize -1 + inBsize*4 + 20, read GNU's cat
// source code. The tl;dr is the 20 is the counter
// buffer, inBsize*4 is from potentially prepending
// the control characters (M-^), and outBsize is
// due to new tests for newlines.
size := outBsize - 1 + inBsize*4 + 20
outBuf := bufio.NewWriterSize(os.Stdout, size)
inBuf := make([]byte, inBsize+1)
ok ^= cat(file, inBuf, outBuf)
}
file.Close()
}
os.Exit(ok)
}
func wc(file *os.File, cur int64, status fstatus) int {
// Our temp number of lines, words, chars, and bytes
var (
lines int64
words int64
chars int64
numBytes int64
lineLength int64
buffer [BufferSize + 1]byte
// Return value.
ok = 0
)
countComplicated := *printWords || *printLineLength
if !*printBytes || *printChars || *printLines || countComplicated {
unix.Fadvise(int(file.Fd()), 0, 0, unix.FADV_SEQUENTIAL)
}
// If we simply want the bytes we can ignore the overhead of
// counting lines, chars, and words
if *printBytes && !*printChars && !*printLines && !countComplicated {
// Manually count bytes if Stat() failed or if we're reading from
// piped input (e.g. cat file.csv | wc -c -)
if status.stat == nil || status.stat.Mode()&os.ModeNamedPipe != 0 {
unix.Fadvise(int(file.Fd()), 0, 0, unix.FADV_SEQUENTIAL)
for {
n, err := file.Read(buffer[:])
if err != nil {
if err != io.EOF {
ok = 1
}
break
}
numBytes += int64(n)
}
} else {
numBytes = status.stat.Size()
end := numBytes
high := end - end%BufferSize
if cur < 0 {
cur, _ = file.Seek(0, os.SEEK_CUR)
}
if 0 <= cur && cur < high {
if n, _ := file.Seek(high, os.SEEK_CUR); 0 <= n {
numBytes = high - cur
}
}
}
// Use a different loop to lower overhead if we're *only* counting
// lines (or lines and bytes)
} else if !*printChars && !countComplicated {
for {
n, err := file.Read(buffer[:])
if err != nil {
if err != io.EOF {
ok = 1
}
break
}
// Go doesn't inline this sooo...
for i := 0; i < n; i++ {
if buffer[i] != '\n' {
o := bytes.IndexByte(buffer[i:n], '\n')
if o < 0 {
break
}
i += o
}
lines++
}
numBytes += int64(n)
}
} else {
var (
inWord int64
linePos int64
)
for {
n, err := file.Read(buffer[:])
if err != nil {
if err != io.EOF {
ok = 1
}
break
}
numBytes += int64(n)
for bp := 0; bp < n; {
r, s := utf8.DecodeRune(buffer[bp:])
switch r {
case '\n':
lines++
fallthrough
case '\r':
fallthrough
case '\f':
if linePos > lineLength {
lineLength = linePos
}
linePos = 0
words += inWord
inWord = 0
case '\t':
linePos += *tabWidth - (linePos % *tabWidth)
words += inWord
inWord = 0
case ' ':
linePos++
fallthrough
case '\v':
words += inWord
inWord = 0
default:
if unicode.IsPrint(r) {
linePos++
if unicode.IsSpace(r) {
words += inWord
inWord = 0
}
inWord = 1
}
}
chars++
bp += s
}
}
if linePos > lineLength {
lineLength = linePos
}
words += inWord
}
writeCounts(lines, words, chars, numBytes, lineLength, file.Name())
totalBytes += numBytes
totalChars += chars
totalLines += lines
totalWords += words
if lineLength > maxLineLength {
maxLineLength = lineLength
}
return ok
}
func tsort(rw io.ReadWriter) int {
var (
root = newItem("")
j *item
k *item
ok int
)
scanner := bufio.NewScanner(rw)
scanner.Split(bufio.ScanWords)
// https://talks.golang.org/2015/tricks.slide#16
if file, ok := rw.(interface {
Fd() uintptr
}); ok {
unix.Fadvise(int(file.Fd()), 0, 0, unix.FADV_SEQUENTIAL)
}
for scanner.Scan() {
k = root.searchItem(scanner.Text())
if j != nil {
recordRelation(j, k)
k = nil
}
j = k
}
if k != nil {
fatal.Fatalln("input contains an odd number of tokens")
}
root.walkTree(countItems)
for numStrings > 0 {
root.walkTree(scanZeros)
for head != nil {
p := head.top
fmt.Fprintln(rw, head.str)
head.str = ""
numStrings--
for p != nil {
p.suc.count--
if p.suc.count == 0 {
zeros.qlink = p.suc
zeros = p.suc
}
p = p.next
}
head = head.qlink
}
if numStrings > 0 {
fatal.Print("tsort: input contains a loop:")
ok = 1
for {
root.walkTree(detectLoop)
if loop == nil {
break
}
}
}
}
return ok
}
func tsort(file *os.File) int {
root := newItem("")
var (
j *item = nil
k *item = nil
)
ok := 0
reader := bufio.NewReader(file)
scanner := bufio.NewScanner(reader)
scanner.Split(bufio.ScanWords)
unix.Fadvise(int(file.Fd()), 0, 0, unix.FADV_SEQUENTIAL)
for scanner.Scan() {
k = root.searchItem(scanner.Text())
if j != nil {
recordRelation(j, k)
k = nil
}
j = k
}
if k != nil {
fatal.Fatalln("input contains an odd number of tokens")
}
root.walkTree(countItems)
for numStrings > 0 {
root.walkTree(scanZeros)
for head != nil {
p := head.top
fmt.Println(head.str)
head.str = ""
numStrings--
for p != nil {
p.suc.count--
if p.suc.count == 0 {
zeros.qlink = p.suc
zeros = p.suc
}
p = p.next
}
head = head.qlink
}
if numStrings > 0 {
fatal.Print("input contains a loop:")
ok = 1
for {
root.walkTree(detectLoop)
if loop == nil {
break
}
}
}
}
return ok
}