Make recursive much much faster

By virtue of parallelism

util.go

@@ -2,10 +2,12 @@ package main
 
 import (
 	"fmt"
-	"io/fs"
+	"log"
 	"os"
 	"path/filepath"
 	"strings"
+	"sync"
+	"sync/atomic"
 	"time"
 )
 
@@ -67,29 +69,62 @@ func GetSyncFilesRecursively(input string, output chan string, status chan error
 	defer close(status)
 
 	var filesProcessed int32
+	var foldersProcessed int32
 	progressTicker := time.NewTicker(200 * time.Millisecond)
 	defer progressTicker.Stop()
 	go func() {
 		for {
+			fmt.Printf("\rFiles processed: %d; Folders processed: %d;", filesProcessed, foldersProcessed)
 			<-progressTicker.C
-			fmt.Printf("\rFiles processed: %d", filesProcessed)
 		}
 	}()
 
-	err := filepath.WalkDir(input, func(path string, file fs.DirEntry, err error) error {
-		if err != nil {
-			return err
-		}
+	var wg sync.WaitGroup
+	wg.Add(1)
+	var initial sync.Once
+	directories := make(chan string, 10000)
+	workerPool := make(chan struct{}, 10000)
+	directories <- input
 
-		// Effectively only find files named "sync" (with no extension!!)
-		if !file.IsDir() && DirRegex.MatchString(path) {
-			output <- path
-		}
-		filesProcessed++
+	log.Printf("%+v", len(workerPool))
+	go func() {
+		for directory := range directories {
+			workerPool <- struct{}{}
+			wg.Add(1)
+			go func(directory string) {
+				atomic.AddInt32(&foldersProcessed, 1)
+				defer wg.Done()
+				defer func() { <-workerPool }()
 
-		return nil
-	})
-	if err != nil {
-		status <- err
-	}
+				// log.Printf("Reading directory %s", directory)
+				files, err := os.ReadDir(directory)
+				if err != nil {
+					log.Printf("Error reading directory %s: %+v", directory, err)
+					return
+				}
+
+				for _, file := range files {
+					// log.Printf("Processing file %s", file.Name())
+					if file.IsDir() {
+						directories <- filepath.Join(directory, file.Name())
+					} else {
+						// log.Println(file.Name(), DirRegex.MatchString(file.Name()))
+						if FileRegex.MatchString(file.Name()) {
+							log.Printf("Writing")
+							output <- filepath.Join(directory, file.Name())
+						}
+						atomic.AddInt32(&filesProcessed, 1)
+					}
+				}
+				// log.Printf("Done reading directory %s", directory)
+			
+				initial.Do(func() {
+					wg.Done()
+				})
+			}(directory)
+		}
+	}()
+
+	wg.Wait()
+	log.Printf("Done")
 }