*.go: ignoreSuffixes to not walk the basedir

and maybe to let the user specify paths too

file/hash.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
 )
 
@@ -23,13 +24,21 @@ type HashInfo struct {
 
 // HashFileGetter walks the provided `path` with `workers` number of threads.
 // The channel of HashInfo are for each regular file encountered.
-func HashFileGetter(path string, hash crypto.Hash, workers int, done <-chan struct{}) <-chan HashInfo {
+func HashFileGetter(path string, hash crypto.Hash, ignoreSuffixes []string, workers int, done <-chan struct{}) <-chan HashInfo {
 	out := make(chan HashInfo, workers)
 	go func() {
 		err := filepath.Walk(path, func(path string, info os.FileInfo, err error) error {
 			if err != nil {
 				return err
 			}
+			for _, suff := range ignoreSuffixes {
+				if os.Getenv("DEBUG") != "" {
+					fmt.Printf("[DEBUG] path: %q ; suff: %q\n", filepath.Clean(path), filepath.Clean(suff))
+				}
+				if strings.HasSuffix(filepath.Clean(path), filepath.Clean(suff)) {
+					return filepath.SkipDir
+				}
+			}
 			if !info.Mode().IsRegular() {
 				return nil
 			}

main.go

@@ -58,11 +58,31 @@ func main() {
 	}
 
 	var (
-		hash = cryptomap.DetermineHash(*flCipher)
+		ignoreSuffixes = []string{}
+		hash           = cryptomap.DetermineHash(*flCipher)
 		//infos = []*file.HashInfo{}
 		//results := make(chan file.HashInfo, 2)
 	)
 
+	bpath, err := filepath.Abs(*flVarBase)
+	if err != nil {
+		log.Fatal(err)
+	}
+	for _, arg := range flag.Args() {
+		apath, err := filepath.Abs(arg)
+		if err != nil {
+			log.Fatal(err)
+		}
+		rel, err := filepath.Rel(apath, bpath)
+		if err != nil {
+			log.Fatal(err)
+		}
+		ignoreSuffixes = append(ignoreSuffixes, rel)
+	}
+	if os.Getenv("DEBUG") != "" {
+		fmt.Printf("[DEBUG] ignoreSuffixes: %#v\n", ignoreSuffixes)
+	}
+
 	for _, arg := range flag.Args() {
 		if !*flNoop {
 			if m, err := file.SameDevPaths(*flVarBase, arg); err != nil {
@@ -73,7 +93,7 @@ func main() {
 			}
 		}
 		done := make(chan struct{})
-		infos := file.HashFileGetter(arg, hash, *flWorkers, done)
+		infos := file.HashFileGetter(arg, hash, ignoreSuffixes, *flWorkers, done)
 		for fi := range infos {
 			if fi.Err != nil {
 				log.Println(fi.Err)