From 131fed28d27729b0eade6beb54cb7b0e16e64fdb Mon Sep 17 00:00:00 2001
From: Alex Grintsvayg <grin@lbry.com>
Date: Fri, 30 Oct 2020 15:01:56 -0400
Subject: [PATCH] add faster file.Walk fn. meant for DiskStore.list()

---
 go.mod                       |  1 +
 go.sum                       |  2 +
 store/speedwalk/speedwalk.go | 84 ++++++++++++++++++++++++++++++++++++
 3 files changed, 87 insertions(+)
 create mode 100644 store/speedwalk/speedwalk.go

diff --git a/go.mod b/go.mod
index b7de5f7..9df120d 100644
--- a/go.mod
+++ b/go.mod
@@ -19,6 +19,7 @@ require (
 	github.com/hashicorp/serf v0.8.2
 	github.com/inconshreveable/go-update v0.0.0-20160112193335-8152e7eb6ccf
 	github.com/johntdyer/slackrus v0.0.0-20180518184837-f7aae3243a07
+	github.com/karrick/godirwalk v1.16.1
 	github.com/lbryio/chainquery v1.9.0
 	github.com/lbryio/lbry.go v1.1.2 // indirect
 	github.com/lbryio/lbry.go/v2 v2.6.1-0.20200901175808-73382bb02128
diff --git a/go.sum b/go.sum
index 01d1580..84b207a 100644
--- a/go.sum
+++ b/go.sum
@@ -188,6 +188,8 @@ github.com/jtolds/gls v4.20.0+incompatible h1:xdiiI2gbIgH/gLH7ADydsJ1uDOEzR8yvV7
 github.com/jtolds/gls v4.20.0+incompatible/go.mod h1:QJZ7F/aHp+rZTRtaJ1ow/lLfFfVYBRgL+9YlvaHOwJU=
 github.com/kardianos/osext v0.0.0-20170510131534-ae77be60afb1 h1:PJPDf8OUfOK1bb/NeTKd4f1QXZItOX389VN3B6qC8ro=
 github.com/kardianos/osext v0.0.0-20170510131534-ae77be60afb1/go.mod h1:1NbS8ALrpOvjt0rHPNLyCIeMtbizbir8U//inJ+zuB8=
+github.com/karrick/godirwalk v1.16.1 h1:DynhcF+bztK8gooS0+NDJFrdNZjJ3gzVzC545UNA9iw=
+github.com/karrick/godirwalk v1.16.1/go.mod h1:j4mkqPuvaLI8mp1DroR3P6ad7cyYd4c1qeJ3RV7ULlk=
 github.com/keybase/go-ps v0.0.0-20161005175911-668c8856d999/go.mod h1:hY+WOq6m2FpbvyrI93sMaypsttvaIL5nhVR92dTMUcQ=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
 github.com/kkdai/bstream v0.0.0-20161212061736-f391b8402d23/go.mod h1:J+Gs4SYgM6CZQHDETBtE9HaSEkGmuNXF86RwHhHUvq4=
diff --git a/store/speedwalk/speedwalk.go b/store/speedwalk/speedwalk.go
new file mode 100644
index 0000000..1c94ed1
--- /dev/null
+++ b/store/speedwalk/speedwalk.go
@@ -0,0 +1,84 @@
+package speedwalk
+
+import (
+	"io/ioutil"
+	"path/filepath"
+	"runtime"
+	"sync"
+
+	"github.com/lbryio/lbry.go/v2/extras/errors"
+
+	"github.com/karrick/godirwalk"
+	"github.com/sirupsen/logrus"
+)
+
+// AllFiles recursively lists every file in every subdirectory of a given directory
+// If basename is true, retun the basename of each file. Otherwise return the full path starting at startDir.
+func AllFiles(startDir string, basename bool) ([]string, error) {
+	items, err := ioutil.ReadDir(startDir)
+	if err != nil {
+		return nil, err
+	}
+
+	pathChan := make(chan string)
+	paths := make([]string, 0, 1000)
+	go func() {
+		for {
+			path, ok := <-pathChan
+			if !ok {
+				return
+			}
+			paths = append(paths, path)
+		}
+	}()
+
+	wg := &sync.WaitGroup{}
+	maxThreads := runtime.NumCPU() - 1
+	goroutineLimiter := make(chan struct{}, maxThreads)
+	for i := 0; i < maxThreads; i++ {
+		goroutineLimiter <- struct{}{}
+	}
+
+	for _, item := range items {
+		if !item.IsDir() {
+			if basename {
+				pathChan <- item.Name()
+			} else {
+				pathChan <- filepath.Join(startDir, item.Name())
+			}
+			continue
+		}
+
+		<-goroutineLimiter
+		wg.Add(1)
+
+		go func(dir string) {
+			defer func() {
+				wg.Done()
+				goroutineLimiter <- struct{}{}
+			}()
+
+			err = godirwalk.Walk(filepath.Join(startDir, dir), &godirwalk.Options{
+				Unsorted: true, // faster this way
+				Callback: func(osPathname string, de *godirwalk.Dirent) error {
+					if de.IsRegular() {
+						if basename {
+							pathChan <- de.Name()
+						} else {
+							pathChan <- filepath.Join(startDir, osPathname)
+						}
+					}
+					return nil
+				},
+			})
+			if err != nil {
+				logrus.Errorf(errors.FullTrace(err))
+			}
+		}(item.Name())
+	}
+
+	wg.Wait()
+
+	close(pathChan)
+	return paths, nil
+}