Add gitea provider

backend/app/gitprovider/common.go

@@ -0,0 +1,105 @@
+package gitprovider
+
+import (
+	"archive/zip"
+	"fmt"
+	"io"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// unzip extracts the zip at src into the dest directory,
+// guarding against zip-slip path traversal attacks.
+func unzip(src, dest string) error {
+	r, err := zip.OpenReader(src)
+	if err != nil {
+		return err
+	}
+	defer r.Close()
+
+	destClean := filepath.Clean(dest) + string(os.PathSeparator)
+
+	for _, f := range r.File {
+		target := filepath.Join(dest, filepath.Clean("/"+f.Name))
+		if !strings.HasPrefix(target, destClean) {
+			return fmt.Errorf("zip slip attempt: %q resolves outside destination", f.Name)
+		}
+
+		if f.FileInfo().IsDir() {
+			if err = os.MkdirAll(target, f.Mode()); err != nil {
+				return err
+			}
+			continue
+		}
+
+		if err = os.MkdirAll(filepath.Dir(target), 0o755); err != nil {
+			return err
+		}
+
+		if err = writeZipEntry(f, target); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func writeZipEntry(f *zip.File, target string) error {
+	rc, err := f.Open()
+	if err != nil {
+		return err
+	}
+	defer rc.Close()
+
+	out, err := os.OpenFile(target, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, f.Mode())
+	if err != nil {
+		return err
+	}
+	defer out.Close()
+
+	_, err = io.Copy(out, rc)
+	return err
+}
+
+// copyDir recursively copies src to dst, preserving file modes.
+// Used as a cross-device fallback when os.Rename fails.
+func copyDir(src, dst string) error {
+	return filepath.WalkDir(src, func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		rel, err := filepath.Rel(src, path)
+		if err != nil {
+			return err
+		}
+		target := filepath.Join(dst, rel)
+
+		if d.IsDir() {
+			return os.MkdirAll(target, 0o755)
+		}
+
+		info, err := d.Info()
+		if err != nil {
+			return err
+		}
+		return copyFile(path, target, info.Mode())
+	})
+}
+
+func copyFile(src, dst string, mode fs.FileMode) error {
+	in, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer in.Close()
+
+	out, err := os.OpenFile(dst, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, mode)
+	if err != nil {
+		return err
+	}
+	defer out.Close()
+
+	_, err = io.Copy(out, in)
+	return err
+}