Merge pull request #47 from rhysd/string-builder

Optimize memory allocations on building patterns with `strings.Builder`

README.md

@@ -1,6 +1,6 @@
 # go-zglob
 
-[![Build Status](https://travis-ci.org/mattn/go-zglob.svg)](https://travis-ci.org/mattn/go-zglob)
+[![Build Status](https://github.com/mattn/go-zglob/actions/workflows/go.yml/badge.svg)](https://github.com/mattn/go-zglob/actions/workflows/go.yml)
 
 zglob
 

zglob.go

@@ -20,11 +20,10 @@ var (
 )
 
 type zenv struct {
- dirmask string
- fre *regexp.Regexp
- braceDir bool
- pattern string
- root string
+ dirmask string
+ fre *regexp.Regexp
+ pattern string
+ root string
 }
 
 func toSlash(path string) string {
@@ -51,7 +50,7 @@ func New(pattern string) (*zenv, error) {
  globmask := ""
  root := ""
  for n, i := range strings.Split(toSlash(pattern), "/") {
- if root == "" && (strings.Index(i, "*") != -1 || strings.Index(i, "{") != -1) {
+ if root == "" && strings.ContainsAny(i, "*{") {
  if globmask == "" {
  root = "."
  } else {
@@ -92,111 +91,119 @@ func New(pattern string) (*zenv, error) {
  globmask = toSlash(path.Clean(globmask))
 
  cc := []rune(globmask)
- dirmask := ""
- filemask := ""
+ var dirmask strings.Builder
+ var filemask strings.Builder
  staticDir := true
  for i := 0; i < len(cc); i++ {
  if i < len(cc)-2 && cc[i] == '\\' {
  i++
- filemask += fmt.Sprintf("[\\x%02X]", cc[i])
+ fmt.Fprintf(&filemask, "[\\x%02X]", cc[i])
  if staticDir {
- dirmask += string(cc[i])
+ dirmask.WriteRune(cc[i])
  }
  } else if cc[i] == '*' {
  staticDir = false
  if i < len(cc)-2 && cc[i+1] == '*' && cc[i+2] == '/' {
- filemask += "(.*/)?"
+ filemask.WriteString("(.*/)?")
  i += 2
  } else {
- filemask += "[^/]*"
+ filemask.WriteString("[^/]*")
  }
  } else if cc[i] == '[' { // range
  staticDir = false
- pattern := ""
+ var b strings.Builder
  for j := i + 1; j < len(cc); j++ {
  if cc[j] == ']' {
  i = j
  break
  } else {
- pattern += string(cc[j])
+ b.WriteRune(cc[j])
  }
  }
- if pattern != "" {
- filemask += "[" + pattern + "]"
+ if pattern := b.String(); pattern != "" {
+ filemask.WriteByte('[')
+ filemask.WriteString(pattern)
+ filemask.WriteByte(']')
  continue
  }
  } else {
  if cc[i] == '{' {
  staticDir = false
- pattern := ""
+ var b strings.Builder
  for j := i + 1; j < len(cc); j++ {
  if cc[j] == ',' {
- pattern += "|"
+ b.WriteByte('|')
  } else if cc[j] == '}' {
  i = j
  break
  } else {
  c := cc[j]
  if c == '/' {
- pattern += string(c)
+ b.WriteRune(c)
  } else if ('0' <= c && c <= '9') || ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z') || 255 < c {
- pattern += string(c)
+ b.WriteRune(c)
  } else {
- pattern += fmt.Sprintf("[\\x%02X]", c)
+ fmt.Fprintf(&b, "[\\x%02X]", c)
  }
  }
  }
- if pattern != "" {
- filemask += "(" + pattern + ")"
+ if pattern := b.String(); pattern != "" {
+ filemask.WriteByte('(')
+ filemask.WriteString(pattern)
+ filemask.WriteByte(')')
  continue
  }
  } else if i < len(cc)-1 && cc[i] == '!' && cc[i+1] == '(' {
  i++
- pattern := ""
+ var b strings.Builder
  for j := i + 1; j < len(cc); j++ {
  if cc[j] == ')' {
  i = j
  break
  } else {
  c := cc[j]
- pattern += fmt.Sprintf("[^\\x%02X/]*", c)
+ fmt.Fprintf(&b, "[^\\x%02X/]*", c)
  }
  }
- if pattern != "" {
- if dirmask == "" {
- dirmask = filemask
- root = filemask
+ if pattern := b.String(); pattern != "" {
+ if dirmask.Len() == 0 {
+ m := filemask.String()
+ dirmask.WriteString(m)
+ root = m
  }
- filemask += pattern
+ filemask.WriteString(pattern)
  continue
  }
  }
  c := cc[i]
  if c == '/' || ('0' <= c && c <= '9') || ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z') || 255 < c {
- filemask += string(c)
+ filemask.WriteRune(c)
  } else {
- filemask += fmt.Sprintf("[\\x%02X]", c)
+ fmt.Fprintf(&filemask, "[\\x%02X]", c)
  }
  if staticDir {
- dirmask += string(c)
+ dirmask.WriteRune(c)
  }
  }
  }
- if len(filemask) > 0 && filemask[len(filemask)-1] == '/' {
+ if m := filemask.String(); len(m) > 0 && m[len(m)-1] == '/' {
  if root == "" {
- root = filemask
+ root = m
  }
- filemask += "[^/]*"
+ filemask.WriteString("[^/]*")
  }
+ var pat string
  if runtime.GOOS == "windows" || runtime.GOOS == "darwin" {
- filemask = "(?i:" + filemask + ")"
+ pat = "^(?i:" + filemask.String() + ")$"
+ } else {
+ pat = "^" + filemask.String() + "$"
  }
- fre, err := regexp.Compile("^" + filemask + "$")
+ fre, err := regexp.Compile(pat)
  if err != nil {
  return nil, err
  }
  return &zenv{
- dirmask: path.Dir(dirmask) + "/",
+ dirmask: path.Dir(dirmask.String()) + "/",
  fre: fre,
  pattern: pattern,
  root: filepath.Clean(root),

zglob_test.go

@@ -59,11 +59,9 @@ func fatalIf(err error) {
  }
 }
 
-func setup(t *testing.T) string {
+func setup() (string, string) {
  tmpdir, err := ioutil.TempDir("", "zglob")
- if err != nil {
- t.Fatal(err)
- }
+ fatalIf(err)
 
  fatalIf(os.MkdirAll(filepath.Join(tmpdir, "foo/baz"), 0755))
  fatalIf(os.MkdirAll(filepath.Join(tmpdir, "foo/bar"), 0755))
@@ -78,22 +76,17 @@ func setup(t *testing.T) string {
  fatalIf(os.MkdirAll(filepath.Join(tmpdir, "zzz/nar/{noo,x}"), 0755))
  fatalIf(ioutil.WriteFile(filepath.Join(tmpdir, "zzz/nar/{noo,x}/joo.png"), []byte{}, 0644))
 
- return tmpdir
+ curdir, err := os.Getwd()
+ fatalIf(err)
+ fatalIf(os.Chdir(tmpdir))
+
+ return tmpdir, curdir
 }
 
 func TestGlob(t *testing.T) {
- tmpdir := setup(t)
+ tmpdir, savedCwd := setup()
  defer os.RemoveAll(tmpdir)
-
- curdir, err := os.Getwd()
- if err != nil {
- t.Fatal(err)
- }
- err = os.Chdir(tmpdir)
- if err != nil {
- t.Fatal(err)
- }
- defer os.Chdir(curdir)
+ defer os.Chdir(savedCwd)
 
  tmpdir = "."
  for _, test := range testGlobs {
@@ -115,18 +108,9 @@ func TestGlob(t *testing.T) {
 }
 
 func TestGlobAbs(t *testing.T) {
- tmpdir := setup(t)
+ tmpdir, savedCwd := setup()
  defer os.RemoveAll(tmpdir)
-
- curdir, err := os.Getwd()
- if err != nil {
- t.Fatal(err)
- }
- err = os.Chdir(tmpdir)
- if err != nil {
- t.Fatal(err)
- }
- defer os.Chdir(curdir)
+ defer os.Chdir(savedCwd)
 
  for _, test := range testGlobs {
  pattern := toSlash(path.Join(tmpdir, test.pattern))
@@ -228,3 +212,24 @@ func TestGlobError(t *testing.T) {
  t.Errorf(`zglob failed: expected %v but got %v`, nil, got)
  }
 }
+
+func BenchmarkGlob(b *testing.B) {
+ tmpdir, savedCwd := setup()
+ defer os.RemoveAll(tmpdir)
+ defer os.Chdir(savedCwd)
+
+ for i := 0; i < b.N; i++ {
+ for _, test := range testGlobs {
+ if test.err != "" {
+ continue
+ }
+ got, err := Glob(test.pattern)
+ if err != nil {
+ b.Fatal(err)
+ }
+ if len(got) != len(test.expected) {
+ b.Fatalf(`zglob failed: pattern %q: expected %v but got %v`, test.pattern, test.expected, got)
+ }
+ }
+ }
+}