/
reader.go
278 lines (255 loc) · 6.11 KB
/
reader.go
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package fzf
import (
"bytes"
"context"
"io"
"os"
"os/exec"
"path/filepath"
"sync"
"sync/atomic"
"time"
"github.com/charlievieth/fastwalk"
"github.com/junegunn/fzf/src/util"
)
// Reader reads from command or standard input
type Reader struct {
pusher func([]byte) bool
executor *util.Executor
eventBox *util.EventBox
delimNil bool
event int32
finChan chan bool
mutex sync.Mutex
exec *exec.Cmd
command *string
killed bool
wait bool
}
// NewReader returns new Reader object
func NewReader(pusher func([]byte) bool, eventBox *util.EventBox, executor *util.Executor, delimNil bool, wait bool) *Reader {
return &Reader{pusher, executor, eventBox, delimNil, int32(EvtReady), make(chan bool, 1), sync.Mutex{}, nil, nil, false, wait}
}
func (r *Reader) startEventPoller() {
go func() {
ptr := &r.event
pollInterval := readerPollIntervalMin
for {
if atomic.CompareAndSwapInt32(ptr, int32(EvtReadNew), int32(EvtReady)) {
r.eventBox.Set(EvtReadNew, (*string)(nil))
pollInterval = readerPollIntervalMin
} else if atomic.LoadInt32(ptr) == int32(EvtReadFin) {
if r.wait {
r.finChan <- true
}
return
} else {
pollInterval += readerPollIntervalStep
if pollInterval > readerPollIntervalMax {
pollInterval = readerPollIntervalMax
}
}
time.Sleep(pollInterval)
}
}()
}
func (r *Reader) fin(success bool) {
atomic.StoreInt32(&r.event, int32(EvtReadFin))
if r.wait {
<-r.finChan
}
r.mutex.Lock()
ret := r.command
if success || r.killed {
ret = nil
}
r.mutex.Unlock()
r.eventBox.Set(EvtReadFin, ret)
}
func (r *Reader) terminate() {
r.mutex.Lock()
r.killed = true
if r.exec != nil && r.exec.Process != nil {
util.KillCommand(r.exec)
} else {
os.Stdin.Close()
}
r.mutex.Unlock()
}
func (r *Reader) restart(command commandSpec, environ []string) {
r.event = int32(EvtReady)
r.startEventPoller()
success := r.readFromCommand(command.command, environ)
r.fin(success)
removeFiles(command.tempFiles)
}
func (r *Reader) readChannel(inputChan chan string) bool {
for {
item, more := <-inputChan
if !more {
break
}
if r.pusher([]byte(item)) {
atomic.StoreInt32(&r.event, int32(EvtReadNew))
}
}
return true
}
// ReadSource reads data from the default command or from standard input
func (r *Reader) ReadSource(inputChan chan string, root string, opts walkerOpts, ignores []string) {
r.startEventPoller()
var success bool
if inputChan != nil {
success = r.readChannel(inputChan)
} else if util.IsTty() {
cmd := os.Getenv("FZF_DEFAULT_COMMAND")
if len(cmd) == 0 {
success = r.readFiles(root, opts, ignores)
} else {
// We can't export FZF_* environment variables to the default command
success = r.readFromCommand(cmd, nil)
}
} else {
success = r.readFromStdin()
}
r.fin(success)
}
func (r *Reader) feed(src io.Reader) {
/*
readerSlabSize, ae := strconv.Atoi(os.Getenv("SLAB_KB"))
if ae != nil {
readerSlabSize = 128 * 1024
} else {
readerSlabSize *= 1024
}
readerBufferSize, be := strconv.Atoi(os.Getenv("BUF_KB"))
if be != nil {
readerBufferSize = 64 * 1024
} else {
readerBufferSize *= 1024
}
*/
delim := byte('\n')
trimCR := util.IsWindows()
if r.delimNil {
delim = '\000'
trimCR = false
}
slab := make([]byte, readerSlabSize)
leftover := []byte{}
var err error
for {
n := 0
scope := slab[:util.Min(len(slab), readerBufferSize)]
for i := 0; i < 100; i++ {
n, err = src.Read(scope)
if n > 0 || err != nil {
break
}
}
// We're not making any progress after 100 tries. Stop.
if n == 0 {
break
}
buf := slab[:n]
slab = slab[n:]
for len(buf) > 0 {
if i := bytes.IndexByte(buf, delim); i >= 0 {
// Found the delimiter
slice := buf[:i+1]
buf = buf[i+1:]
if trimCR && len(slice) >= 2 && slice[len(slice)-2] == byte('\r') {
slice = slice[:len(slice)-2]
} else {
slice = slice[:len(slice)-1]
}
if len(leftover) > 0 {
slice = append(leftover, slice...)
leftover = []byte{}
}
if (err == nil || len(slice) > 0) && r.pusher(slice) {
atomic.StoreInt32(&r.event, int32(EvtReadNew))
}
} else {
// Could not find the delimiter in the buffer
// NOTE: We can further optimize this by keeping track of the cursor
// position in the slab so that a straddling item that doesn't go
// beyond the boundary of a slab doesn't need to be copied to
// another buffer. However, the performance gain is negligible in
// practice (< 0.1%) and is not
// worth the added complexity.
leftover = append(leftover, buf...)
break
}
}
if err == io.EOF {
leftover = append(leftover, buf...)
break
}
if len(slab) == 0 {
slab = make([]byte, readerSlabSize)
}
}
if len(leftover) > 0 && r.pusher(leftover) {
atomic.StoreInt32(&r.event, int32(EvtReadNew))
}
}
func (r *Reader) readFromStdin() bool {
r.feed(os.Stdin)
return true
}
func (r *Reader) readFiles(root string, opts walkerOpts, ignores []string) bool {
r.killed = false
conf := fastwalk.Config{Follow: opts.follow}
fn := func(path string, de os.DirEntry, err error) error {
if err != nil {
return nil
}
path = filepath.Clean(path)
if path != "." {
isDir := de.IsDir()
if isDir {
base := filepath.Base(path)
if !opts.hidden && base[0] == '.' {
return filepath.SkipDir
}
for _, ignore := range ignores {
if ignore == base {
return filepath.SkipDir
}
}
}
if ((opts.file && !isDir) || (opts.dir && isDir)) && r.pusher([]byte(path)) {
atomic.StoreInt32(&r.event, int32(EvtReadNew))
}
}
r.mutex.Lock()
defer r.mutex.Unlock()
if r.killed {
return context.Canceled
}
return nil
}
return fastwalk.Walk(&conf, root, fn) == nil
}
func (r *Reader) readFromCommand(command string, environ []string) bool {
r.mutex.Lock()
r.killed = false
r.command = &command
r.exec = r.executor.ExecCommand(command, true)
if environ != nil {
r.exec.Env = environ
}
out, err := r.exec.StdoutPipe()
if err != nil {
r.mutex.Unlock()
return false
}
err = r.exec.Start()
r.mutex.Unlock()
if err != nil {
return false
}
r.feed(out)
return r.exec.Wait() == nil
}