Implemented a basic scanner

src/fs/File.go

@@ -0,0 +1,8 @@
+package fs
+
+// File represents a single source file.
+type File struct {
+	Path    string
+	Package string
+	Bytes   []byte
+}

src/fs/Walk_fast.go

@@ -0,0 +1,61 @@
+//go:build linux || darwin
+
+package fs
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+// Walk calls your callback function for every file name inside the directory.
+// It doesn't distinguish between files and directories.
+func Walk(directory string, callBack func(string)) error {
+	fd, err := syscall.Open(directory, 0, 0)
+
+	if err != nil {
+		return err
+	}
+
+	defer syscall.Close(fd)
+	buffer := make([]byte, 1024)
+
+	for {
+		n, err := syscall.ReadDirent(fd, buffer)
+
+		if err != nil {
+			return err
+		}
+
+		if n <= 0 {
+			break
+		}
+
+		readBuffer := buffer[:n]
+
+		for len(readBuffer) > 0 {
+			dirent := (*syscall.Dirent)(unsafe.Pointer(&readBuffer[0]))
+			readBuffer = readBuffer[dirent.Reclen:]
+
+			if dirent.Ino == 0 {
+				continue
+			}
+
+			if dirent.Name[0] == '.' {
+				continue
+			}
+
+			for i, c := range dirent.Name {
+				if c != 0 {
+					continue
+				}
+
+				bytePointer := (*byte)(unsafe.Pointer(&dirent.Name[0]))
+				name := unsafe.String(bytePointer, i)
+				callBack(name)
+				break
+			}
+		}
+	}
+
+	return nil
+}

src/fs/Walk_slow.go

@@ -0,0 +1,28 @@
+//go:build !linux && !darwin
+
+package fs
+
+import "os"
+
+// Walk calls your callback function for every file name inside the directory.
+// It doesn't distinguish between files and directories.
+func Walk(directory string, callBack func(string)) error {
+	f, err := os.Open(directory)
+
+	if err != nil {
+		return err
+	}
+
+	files, err := f.Readdirnames(0)
+	f.Close()
+
+	if err != nil {
+		return err
+	}
+
+	for _, file := range files {
+		callBack(file)
+	}
+
+	return nil
+}

src/fs/Walk_test.go

@@ -0,0 +1,29 @@
+package fs_test
+
+import (
+	"testing"
+
+	"git.urbach.dev/cli/q/src/fs"
+	"git.urbach.dev/go/assert"
+)
+
+func TestWalk(t *testing.T) {
+	var files []string
+
+	err := fs.Walk(".", func(file string) {
+		files = append(files, file)
+	})
+
+	assert.Nil(t, err)
+	assert.Contains(t, files, "Walk_test.go")
+}
+
+func TestWalkNotDirectory(t *testing.T) {
+	err := fs.Walk("Walk_test.go", func(file string) {})
+	assert.NotNil(t, err)
+}
+
+func TestWalkNotExisting(t *testing.T) {
+	err := fs.Walk("_", func(file string) {})
+	assert.NotNil(t, err)
+}

src/fs/bench_test.go

@@ -0,0 +1,42 @@
+package fs_test
+
+import (
+	"os"
+	"testing"
+
+	"git.urbach.dev/cli/q/src/fs"
+	"git.urbach.dev/go/assert"
+)
+
+func BenchmarkReadDir(b *testing.B) {
+	for b.Loop() {
+		files, err := os.ReadDir(".")
+		assert.Nil(b, err)
+
+		for _, file := range files {
+			func(string) {}(file.Name())
+		}
+	}
+}
+
+func BenchmarkReaddirnames(b *testing.B) {
+	for b.Loop() {
+		f, err := os.Open(".")
+		assert.Nil(b, err)
+		files, err := f.Readdirnames(0)
+		assert.Nil(b, err)
+
+		for _, file := range files {
+			func(string) {}(file)
+		}
+
+		f.Close()
+	}
+}
+
+func BenchmarkWalk(b *testing.B) {
+	for b.Loop() {
+		err := fs.Walk(".", func(string) {})
+		assert.Nil(b, err)
+	}
+}