100 lines
2.3 KiB
Go
100 lines
2.3 KiB
Go
package pwalk
|
|
|
|
import (
|
|
"os"
|
|
"path/filepath"
|
|
"runtime"
|
|
"sync"
|
|
|
|
"github.com/pkg/errors"
|
|
)
|
|
|
|
type WalkFunc = filepath.WalkFunc
|
|
|
|
// Walk is a wrapper for filepath.Walk which can call multiple walkFn
|
|
// in parallel, allowing to handle each item concurrently. A maximum of
|
|
// twice the runtime.NumCPU() walkFn will be called at any one time.
|
|
// If you want to change the maximum, use WalkN instead.
|
|
//
|
|
// The order of calls is non-deterministic.
|
|
//
|
|
// Note that this implementation only supports primitive error handling:
|
|
//
|
|
// * no errors are ever passed to WalkFn
|
|
//
|
|
// * once a walkFn returns any error, all further processing stops
|
|
// and the error is returned to the caller of Walk;
|
|
//
|
|
// * filepath.SkipDir is not supported;
|
|
//
|
|
// * if more than one walkFn instance will return an error, only one
|
|
// of such errors will be propagated and returned by Walk, others
|
|
// will be silently discarded.
|
|
//
|
|
func Walk(root string, walkFn WalkFunc) error {
|
|
return WalkN(root, walkFn, runtime.NumCPU()*2)
|
|
}
|
|
|
|
// WalkN is a wrapper for filepath.Walk which can call multiple walkFn
|
|
// in parallel, allowing to handle each item concurrently. A maximum of
|
|
// num walkFn will be called at any one time.
|
|
func WalkN(root string, walkFn WalkFunc, num int) error {
|
|
// make sure limit is sensible
|
|
if num < 1 {
|
|
return errors.Errorf("walk(%q): num must be > 0", root)
|
|
}
|
|
|
|
files := make(chan *walkArgs, 2*num)
|
|
errCh := make(chan error, 1) // get the first error, ignore others
|
|
|
|
// Start walking a tree asap
|
|
var err error
|
|
go func() {
|
|
err = filepath.Walk(root, func(p string, info os.FileInfo, err error) error {
|
|
if err != nil {
|
|
close(files)
|
|
return err
|
|
}
|
|
// add a file to the queue unless a callback sent an error
|
|
select {
|
|
case e := <-errCh:
|
|
close(files)
|
|
return e
|
|
default:
|
|
files <- &walkArgs{path: p, info: &info}
|
|
return nil
|
|
}
|
|
})
|
|
if err == nil {
|
|
close(files)
|
|
}
|
|
}()
|
|
|
|
var wg sync.WaitGroup
|
|
wg.Add(num)
|
|
for i := 0; i < num; i++ {
|
|
go func() {
|
|
for file := range files {
|
|
if e := walkFn(file.path, *file.info, nil); e != nil {
|
|
select {
|
|
case errCh <- e: // sent ok
|
|
default: // buffer full
|
|
}
|
|
}
|
|
}
|
|
wg.Done()
|
|
}()
|
|
}
|
|
|
|
wg.Wait()
|
|
|
|
return err
|
|
}
|
|
|
|
// walkArgs holds the arguments that were passed to the Walk or WalkLimit
|
|
// functions.
|
|
type walkArgs struct {
|
|
path string
|
|
info *os.FileInfo
|
|
}
|