reflog: add a convenience append function

Provide a function that reads a reflog, performs an append and writes back to the
backend in one call.

include/git2/reflog.h

@@ -60,6 +60,23 @@ GIT_EXTERN(int) git_reflog_write(git_reflog *reflog);
 GIT_EXTERN(int) git_reflog_append(git_reflog *reflog, const git_oid *id, const git_signature *committer, const char *msg);
 
 /**
+ * Add a new entry to the named reflog.
+ *
+ * This utility function loads the named reflog, appends to it and
+ * writes it back out to the backend.
+ *
+ * `msg` is optional and can be NULL.
+ *
+ * @param repo the repository to act on
+ * @param name the reflog's name
+ * @param id the OID the reference is now pointing to
+ * @param committer the signature of the committer
+ * @param msg the reflog message
+ * @return 0 or an error code
+ */
+GIT_EXTERN(int) git_reflog_append_to(git_repository *repo, const char *name, const git_oid *id, const git_signature *committer, const char *msg);
+
+/**
  * Rename a reflog
  *
  * The reflog to be renamed is expected to already exist

src/reflog.c

@@ -158,3 +158,22 @@ int git_reflog_drop(
 	db = reflog->db;
 	return db->backend->reflog_drop(db->backend, reflog, idx, rewrite_previous_entry);
 }
+
+int git_reflog_append_to(git_repository *repo, const char *name, const git_oid *id,
+			 const git_signature *committer, const char *msg)
+{
+	int error;
+	git_reflog *reflog;
+
+	if ((error = git_reflog_read(&reflog, repo, name)) < 0)
+		return error;
+
+	if ((error = git_reflog_append(reflog, id, committer, msg)) < 0)
+		goto cleanup;
+
+	error = git_reflog_write(reflog);
+
+cleanup:
+	git_reflog_free(reflog);
+	return error;
+}

tests-clar/refs/reflog/reflog.c

@@ -13,7 +13,7 @@ static git_repository *g_repo;
 
 
 // helpers
-static void assert_signature(git_signature *expected, git_signature *actual)
+static void assert_signature(const git_signature *expected, const git_signature *actual)
 {
 	cl_assert(actual);
 	cl_assert_equal_s(expected->name, actual->name);
@@ -34,30 +34,13 @@ void test_refs_reflog_reflog__cleanup(void)
    cl_git_sandbox_cleanup();
 }
 
-void test_refs_reflog_reflog__append_then_read(void)
+static void assert_appends(const git_signature *committer, const git_oid *oid)
 {
-   // write a reflog for a given reference and ensure it can be read back
 	git_repository *repo2;
-	git_reference *ref, *lookedup_ref;
-	git_oid oid;
-	git_signature *committer;
+	git_reference *lookedup_ref;
 	git_reflog *reflog;
 	const git_reflog_entry *entry;
 
-	/* Create a new branch pointing at the HEAD */
-	git_oid_fromstr(&oid, current_master_tip);
-	cl_git_pass(git_reference_create(&ref, g_repo, new_ref, &oid, 0));
-
-	cl_git_pass(git_signature_now(&committer, "foo", "foo@bar"));
-
-	cl_git_pass(git_reflog_read(&reflog, g_repo, new_ref));
-
-	cl_git_fail(git_reflog_append(reflog, &oid, committer, "no inner\nnewline"));
-	cl_git_pass(git_reflog_append(reflog, &oid, committer, NULL));
-	cl_git_pass(git_reflog_append(reflog, &oid, committer, commit_msg "\n"));
-	cl_git_pass(git_reflog_write(reflog));
-	git_reflog_free(reflog);
-
 	/* Reopen a new instance of the repository */
 	cl_git_pass(git_repository_open(&repo2, "testrepo.git"));
 
@@ -71,23 +54,72 @@ void test_refs_reflog_reflog__append_then_read(void)
 	entry = git_reflog_entry_byindex(reflog, 1);
 	assert_signature(committer, entry->committer);
 	cl_assert(git_oid_streq(&entry->oid_old, GIT_OID_HEX_ZERO) == 0);
-	cl_assert(git_oid_cmp(&oid, &entry->oid_cur) == 0);
+	cl_assert(git_oid_cmp(oid, &entry->oid_cur) == 0);
 	cl_assert(entry->msg == NULL);
 
 	entry = git_reflog_entry_byindex(reflog, 0);
 	assert_signature(committer, entry->committer);
-	cl_assert(git_oid_cmp(&oid, &entry->oid_old) == 0);
-	cl_assert(git_oid_cmp(&oid, &entry->oid_cur) == 0);
+	cl_assert(git_oid_cmp(oid, &entry->oid_old) == 0);
+	cl_assert(git_oid_cmp(oid, &entry->oid_cur) == 0);
 	cl_assert_equal_s(commit_msg, entry->msg);
 
-	git_signature_free(committer);
 	git_reflog_free(reflog);
 	git_repository_free(repo2);
 
-	git_reference_free(ref);
 	git_reference_free(lookedup_ref);
 }
 
+void test_refs_reflog_reflog__append_then_read(void)
+{
+	/* write a reflog for a given reference and ensure it can be read back */
+	git_reference *ref;
+	git_oid oid;
+	git_signature *committer;
+	git_reflog *reflog;
+
+	/* Create a new branch pointing at the HEAD */
+	git_oid_fromstr(&oid, current_master_tip);
+	cl_git_pass(git_reference_create(&ref, g_repo, new_ref, &oid, 0));
+	git_reference_free(ref);
+
+	cl_git_pass(git_signature_now(&committer, "foo", "foo@bar"));
+
+	cl_git_pass(git_reflog_read(&reflog, g_repo, new_ref));
+
+	cl_git_fail(git_reflog_append(reflog, &oid, committer, "no inner\nnewline"));
+	cl_git_pass(git_reflog_append(reflog, &oid, committer, NULL));
+	cl_git_pass(git_reflog_append(reflog, &oid, committer, commit_msg "\n"));
+	cl_git_pass(git_reflog_write(reflog));
+	git_reflog_free(reflog);
+
+	assert_appends(committer, &oid);
+
+	git_signature_free(committer);
+}
+
+void test_refs_reflog_reflog__append_to_then_read(void)
+{
+	/* write a reflog for a given reference and ensure it can be read back */
+	git_reference *ref;
+	git_oid oid;
+	git_signature *committer;
+
+	/* Create a new branch pointing at the HEAD */
+	git_oid_fromstr(&oid, current_master_tip);
+	cl_git_pass(git_reference_create(&ref, g_repo, new_ref, &oid, 0));
+	git_reference_free(ref);
+
+	cl_git_pass(git_signature_now(&committer, "foo", "foo@bar"));
+
+	cl_git_fail(git_reflog_append_to(g_repo, new_ref, &oid, committer, "no inner\nnewline"));
+	cl_git_pass(git_reflog_append_to(g_repo, new_ref, &oid, committer, NULL));
+	cl_git_pass(git_reflog_append_to(g_repo, new_ref, &oid, committer, commit_msg "\n"));
+
+	assert_appends(committer, &oid);
+
+	git_signature_free(committer);
+}
+
 void test_refs_reflog_reflog__renaming_the_reference_moves_the_reflog(void)
 {
 	git_reference *master, *new_master;