From 29601ccaf75ffa6a0cdc2e6bcaedaa5a573f59a2 Mon Sep 17 00:00:00 2001
From: Runxi Yu <me@runxiyu.org>
Date: Sat, 05 Apr 2025 11:58:21 +0800
Subject: [PATCH] git2d: Add a basic command for tree

---
 git2d/cmd2.c    | 122 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 git2d/session.c |   5 +++++
 git2d/x.h       |   1 +

diff --git a/git2d/cmd2.c b/git2d/cmd2.c
new file mode 100644
index 0000000000000000000000000000000000000000..6edacf29632659a65571fc6b86c3a42ffef0d483
--- /dev/null
+++ b/git2d/cmd2.c
@@ -0,0 +1,122 @@
+/*-
+ * SPDX-License-Identifier: AGPL-3.0-only
+ * SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org>
+ */
+
+#include "x.h"
+
+int
+cmd2(git_repository *repo, struct bare_reader *reader, struct bare_writer *writer)
+{
+	/* Path */
+	char path[4096] = {0};
+	int err = bare_get_data(reader, (uint8_t *)path, sizeof(path) - 1);
+	if (err != BARE_ERROR_NONE) {
+		bare_put_uint(writer, 10);
+		return -1;
+	}
+	path[sizeof(path) - 1] = '\0';
+
+	/* HEAD^{tree} */
+	git_object *head_obj = NULL;
+	err = git_revparse_single(&head_obj, repo, "HEAD^{tree}");
+	if (err != 0) {
+		bare_put_uint(writer, 11);
+		return -1;
+	}
+	git_tree *tree = (git_tree *)head_obj;
+
+	/* Path in tree */
+	git_tree_entry *entry = NULL;
+	git_otype objtype;
+	if (strlen(path) == 0) {
+		entry = NULL;
+		objtype = GIT_OBJECT_TREE;
+	} else {
+		err = git_tree_entry_bypath(&entry, tree, path);
+		if (err != 0) {
+			bare_put_uint(writer, 3);
+			git_tree_free(tree);
+			return 0;
+		}
+		objtype = git_tree_entry_type(entry);
+	}
+
+	if (objtype == GIT_OBJECT_TREE) {
+		/* Tree */
+		git_object *tree_obj = NULL;
+		if (entry == NULL) {
+			tree_obj = (git_object *)tree;
+		} else {
+			err = git_tree_entry_to_object(&tree_obj, repo, entry);
+			if (err != 0) {
+				bare_put_uint(writer, 3);
+				goto cleanup;
+			}
+		}
+		git_tree *subtree = (git_tree *)tree_obj;
+
+		size_t count = git_tree_entrycount(subtree);
+		bare_put_uint(writer, 0);
+		bare_put_uint(writer, 1);
+		bare_put_uint(writer, count);
+		for (size_t i = 0; i < count; i++) {
+			const git_tree_entry *subentry = git_tree_entry_byindex(subtree, i);
+			const char *name = git_tree_entry_name(subentry);
+			git_otype type = git_tree_entry_type(subentry);
+			uint32_t mode = git_tree_entry_filemode(subentry);
+
+			uint8_t entry_type = 0;
+			uint64_t size = 0;
+
+			if (type == GIT_OBJECT_TREE) {
+				entry_type = 1;
+			} else if (type == GIT_OBJECT_BLOB) {
+				entry_type = 2;
+
+				git_object *subobj = NULL;
+				if (git_tree_entry_to_object(&subobj, repo, subentry) == 0) {
+					git_blob *b = (git_blob *)subobj;
+					size = git_blob_rawsize(b);
+					git_blob_free(b);
+				}
+			}
+
+			bare_put_uint(writer, entry_type);
+			bare_put_uint(writer, mode);
+			bare_put_uint(writer, size);
+			bare_put_data(writer, (const uint8_t *)name, strlen(name));
+		}
+		if (entry != NULL) {
+			git_tree_free(subtree);
+		}
+	} else if (objtype == GIT_OBJECT_BLOB) {
+		/* Blob */
+		git_object *blob_obj = NULL;
+		err = git_tree_entry_to_object(&blob_obj, repo, entry);
+		if (err != 0) {
+			bare_put_uint(writer, 3);
+			goto cleanup;
+		}
+		git_blob *blob = (git_blob *)blob_obj;
+		const void *content = git_blob_rawcontent(blob);
+		if (content == NULL) {
+			bare_put_uint(writer, 3);
+			git_blob_free(blob);
+			goto cleanup;
+		}
+		bare_put_uint(writer, 0);
+		bare_put_uint(writer, 2);
+		bare_put_data(writer, content, git_blob_rawsize(blob));
+		git_blob_free(blob);
+	} else {
+		/* Unknown */
+		bare_put_uint(writer, 3);
+	}
+
+cleanup:
+	if (entry != NULL)
+		git_tree_entry_free(entry);
+	git_tree_free(tree);
+	return 0;
+}
diff --git a/git2d/session.c b/git2d/session.c
index f7ad8439a962a2f95c76b273001952fd11981570..5efd218a4fd99eb4650542d51808fc29944023cf 100644
--- a/git2d/session.c
+++ b/git2d/session.c
@@ -52,6 +52,11 @@ 		err = cmd1(repo, &writer);
 		if (err != 0)
 			goto free_repo;
 		break;
+	case 2:
+		err = cmd2(repo, &reader, &writer);
+		if (err != 0)
+			goto free_repo;
+		break;
 	case 0:
 		bare_put_uint(&writer, 3);
 		goto free_repo;
diff --git a/git2d/x.h b/git2d/x.h
index f852b2369be0313ae94700cc8059262b76318391..5a9b32ac33883152fb982777704568338df666c7 100644
--- a/git2d/x.h
+++ b/git2d/x.h
@@ -33,5 +33,6 @@
 void * session(void *_conn);
 
 int cmd1(git_repository *repo, struct bare_writer *writer);
+int cmd2(git_repository *repo, struct bare_reader *reader, struct bare_writer *writer);
 
 #endif // X_H

-- 
2.48.1