initial commit

1 files changed, 124 insertions, 0 deletions

diff --git a/main.go b/main.go
new file mode 100644
index 0000000..9cb32f2
--- /dev/null
+++ b/main.go
@@ -0,0 +1,124 @@
+package main
+
+import (
+	"bufio"
+	"crypto/sha256"
+	"fmt"
+	"io/fs"
+	"log"
+	"net/url"
+	"os"
+	"path/filepath"
+	"time"
+)
+
+type metadata struct {
+	size, mtime, mode int64
+	// sum               [sha256.Size]byte
+	sum []byte
+}
+
+type metamap map[string]metadata
+
+func getIndex(root string, mm metamap) (index string, err error) {
+	filesystem := os.DirFS(root)
+	err = fs.WalkDir(filesystem, ".", func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		info, err := d.Info()
+		if err != nil {
+			return err
+		}
+		if info.IsDir() {
+			if d.Name() == ".bb" {
+				return fs.SkipDir
+			}
+			return nil
+		}
+
+		b, err := os.ReadFile(path)
+		if err != nil {
+			return err
+		}
+
+		// md := metadata{info.Size(), info.ModTime().Unix(), int64(info.Mode()), sha256.Sum256(b)}
+		a := sha256.Sum256(b)
+		md := metadata{info.Size(), info.ModTime().Unix(), int64(info.Mode()), a[:]}
+
+		log.Println(path, md, mm[path])
+
+		index += fmt.Sprintf("%s %d %d %o %x\n", url.PathEscape(path), md.size, md.mtime, md.mode, md.sum)
+		return nil
+	})
+	return index, err
+}
+
+func readIndex(path string) (md metamap, err error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return md, err
+	}
+	defer f.Close()
+	md = metamap{}
+	scan := bufio.NewScanner(f)
+	for scan.Scan() {
+		var p string
+		var d metadata
+		n, err := fmt.Sscanf(scan.Text(), "%s %d %d %o %64x", &p, &d.size, &d.mtime, &d.mode, &d.sum)
+		if err != nil || n != 5 {
+			return md, err
+		}
+		path, err := url.PathUnescape(p)
+		if err != nil {
+			return md, err
+		}
+		md[path] = d
+	}
+	if err := scan.Err(); err != nil {
+		return md, err
+	}
+	return md, nil
+}
+
+func initBB(root string) (current, previous string, err error) {
+	if err = os.MkdirAll(filepath.Join(root, ".bb", "data"), 0o750); err != nil {
+		return "", "", err
+	}
+	prevs, _ := fs.Glob(os.DirFS(root), filepath.Join(".bb", "index-*"))
+	if len(prevs) > 0 {
+		previous = prevs[len(prevs)-1]
+	}
+	now := time.Now()
+	y, m, d := now.Date()
+	h, mn, s := now.Clock()
+	current = filepath.Join(root, ".bb", fmt.Sprintf("index-%d-%02d%02d-%02d%02d%02d", y, m, d, h, mn, s))
+	return current, previous, nil
+}
+
+func main() {
+	log.SetFlags(log.Lshortfile)
+	wd, err := os.Getwd()
+	if err != nil {
+		log.Fatal(err)
+	}
+	index, oldindex, err := initBB(wd)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	md := metamap{}
+	if oldindex != "" {
+		if md, err = readIndex(oldindex); err != nil {
+			log.Fatal(err)
+		}
+	}
+	data, err := getIndex(wd, md)
+	if err != nil {
+		log.Fatal(err)
+	}
+	err = os.WriteFile(index, []byte(data), 0o644)
+	if err != nil {
+		log.Fatal(err)
+	}
+}