1 files changed, 107 insertions, 0 deletions
diff --git a/internal/unsorted/http_handle_repo_info.go b/internal/unsorted/http_handle_repo_info.go
new file mode 100644
index 0000000..e23b1d2
--- /dev/null
+++ b/internal/unsorted/http_handle_repo_info.go
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+// SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org>
+
+package unsorted
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"os/exec"
+
+	"github.com/jackc/pgx/v5/pgtype"
+)
+
+// httpHandleRepoInfo provides advertised refs of a repo for use in Git's Smart
+// HTTP protocol.
+//
+// TODO: Reject access from web browsers.
+func (s *Server) httpHandleRepoInfo(writer http.ResponseWriter, request *http.Request, params map[string]any) (err error) {
+	groupPath := params["group_path"].([]string)
+	repoName := params["repo_name"].(string)
+	var repoPath string
+
+	if err := s.database.QueryRow(request.Context(), `
+	WITH RECURSIVE group_path_cte AS (
+		-- Start: match the first name in the path where parent_group IS NULL
+		SELECT
+			id,
+			parent_group,
+			name,
+			1 AS depth
+		FROM groups
+		WHERE name = ($1::text[])[1]
+			AND parent_group IS NULL
+	
+		UNION ALL
+	
+		-- Recurse: jion next segment of the path
+		SELECT
+			g.id,
+			g.parent_group,
+			g.name,
+			group_path_cte.depth + 1
+		FROM groups g
+		JOIN group_path_cte ON g.parent_group = group_path_cte.id
+		WHERE g.name = ($1::text[])[group_path_cte.depth + 1]
+			AND group_path_cte.depth + 1 <= cardinality($1::text[])
+	)
+	SELECT r.filesystem_path
+	FROM group_path_cte c
+	JOIN repos r ON r.group_id = c.id
+	WHERE c.depth = cardinality($1::text[])
+		AND r.name = $2
+	`,
+		pgtype.FlatArray[string](groupPath),
+		repoName,
+	).Scan(&repoPath); err != nil {
+		return err
+	}
+
+	writer.Header().Set("Content-Type", "application/x-git-upload-pack-advertisement")
+	writer.WriteHeader(http.StatusOK)
+
+	cmd := exec.Command("git", "upload-pack", "--stateless-rpc", "--advertise-refs", repoPath)
+	stdout, err := cmd.StdoutPipe()
+	if err != nil {
+		return err
+	}
+	defer func() {
+		_ = stdout.Close()
+	}()
+	cmd.Stderr = cmd.Stdout
+
+	if err = cmd.Start(); err != nil {
+		return err
+	}
+
+	if err = packLine(writer, "# service=git-upload-pack\n"); err != nil {
+		return err
+	}
+
+	if err = packFlush(writer); err != nil {
+		return
+	}
+
+	if _, err = io.Copy(writer, stdout); err != nil {
+		return err
+	}
+
+	if err = cmd.Wait(); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Taken from https://github.com/icyphox/legit, MIT license.
+func packLine(w io.Writer, s string) error {
+	_, err := fmt.Fprintf(w, "%04x%s", len(s)+4, s)
+	return err
+}
+
+// Taken from https://github.com/icyphox/legit, MIT license.
+func packFlush(w io.Writer) error {
+	_, err := fmt.Fprint(w, "0000")
+	return err
+}