reflog: move the reflog implementation into refdb_fs

References and their logs are logically coupled, let's make it so in
the code by moving the fs-based reflog implementation to live next to
the fs-based refs one.

As part of the change, make the function take names rather than
references, as only the names are relevant when looking up and
handling reflogs.

include/git2/reflog.h

@@ -31,10 +31,11 @@ GIT_BEGIN_DECL
  * git_reflog_free().
  *
  * @param out pointer to reflog
- * @param ref reference to read the reflog for
+ * @param repo the repostiory
+ * @param name reference to look up
  * @return 0 or an error code
  */
-GIT_EXTERN(int) git_reflog_read(git_reflog **out, const git_reference *ref);
+GIT_EXTERN(int) git_reflog_read(git_reflog **out, git_repository *repo,  const char *name);
 
 /**
  * Write an existing in-memory reflog object back to disk
@@ -59,26 +60,28 @@ 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);
 
 /**
- * Rename the reflog for the given reference
+ * Rename a reflog
  *
  * The reflog to be renamed is expected to already exist
  *
  * The new name will be checked for validity.
  * See `git_reference_create_symbolic()` for rules about valid names.
  *
- * @param ref the reference
- * @param name the new name of the reference
+ * @param repo the repository
+ * @param old_name the old name of the reference
+ * @param new_name the new name of the reference
  * @return 0 on success, GIT_EINVALIDSPEC or an error code
  */
-GIT_EXTERN(int) git_reflog_rename(git_reference *ref, const char *name);
+GIT_EXTERN(int) git_reflog_rename(git_repository *repo, const char *old_name, const char *name);
 
 /**
  * Delete the reflog for the given reference
  *
- * @param ref the reference
+ * @param repo the repository
+ * @param name the reflog to delete
  * @return 0 or an error code
  */
-GIT_EXTERN(int) git_reflog_delete(git_reference *ref);
+GIT_EXTERN(int) git_reflog_delete(git_repository *repo, const char *name);
 
 /**
  * Get the number of log entries in a reflog

include/git2/sys/refdb_backend.h

@@ -119,6 +119,38 @@ struct git_refdb_backend {
 	 * provide this function; if it is not provided, nothing will be done.
 	 */
 	void (*free)(git_refdb_backend *backend);
+
+	/**
+	 * Read the reflog for the given reference name.
+	 */
+	int (*reflog_read)(git_reflog **out, git_refdb_backend *backend, const char *name);
+
+	/**
+	 * Write a reflog to disk.
+	 */
+	int (*reflog_write)(git_refdb_backend *backend, git_reflog *reflog);
+
+	/**
+	 * Append an entry to the given reflog
+	 */
+	int (*reflog_append)(git_refdb_backend *backend, git_reflog *reflog,
+			     const git_oid *new_oid, const git_signature *committer,
+			     const char *msg);
+
+	/**
+	 * Rename a reflog
+	 */
+	int (*reflog_rename)(git_refdb_backend *_backend, const char *old_name, const char *new_name);
+
+	/**
+	 * Drop an entry from the reflog
+	 */
+	int (*reflog_drop)(git_refdb_backend *_backend, git_reflog *reflog,
+			   size_t idx, int rewrite_previous_entry);
+	/**
+	 * Remove a reflog.
+	 */
+	int (*reflog_delete)(git_refdb_backend *backend, const char *name);
 };
 
 #define GIT_REFDB_BACKEND_VERSION 1

include/git2/sys/reflog.h

+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_sys_git_reflog_h__
+#define INCLUDE_sys_git_reflog_h__
+
+#include "git2/common.h"
+#include "git2/types.h"
+#include "git2/oid.h"
+
+GIT_BEGIN_DECL
+
+GIT_EXTERN(git_reflog_entry *) git_reflog_entry__alloc(void);
+GIT_EXTERN(void) git_reflog_entry__free(git_reflog_entry *entry);
+
+GIT_END_DECL
+
+#endif

src/refdb.c

@@ -16,6 +16,7 @@
 #include "hash.h"
 #include "refdb.h"
 #include "refs.h"
+#include "reflog.h"
 
 int git_refdb_new(git_refdb **out, git_repository *repo)
 {
@@ -203,3 +204,18 @@ int git_refdb_delete(struct git_refdb *db, const char *ref_name)
 	assert(db && db->backend);
 	return db->backend->del(db->backend, ref_name);
 }
+
+int git_refdb_reflog_read(git_reflog **out, git_refdb *db,  const char *name)
+{
+	int error;
+
+	assert(db && db->backend);
+
+	if ((error = db->backend->reflog_read(out, db->backend, name)) < 0)
+		return error;
+
+	GIT_REFCOUNT_INC(db);
+	(*out)->db = db;
+
+	return 0;
+}

src/refdb.h

@@ -43,4 +43,8 @@ void git_refdb_iterator_free(git_reference_iterator *iter);
 int git_refdb_write(git_refdb *refdb, git_reference *ref, int force);
 int git_refdb_delete(git_refdb *refdb, const char *ref_name);
 
+int git_refdb_reflog_read(git_reflog **out, git_refdb *db,  const char *name);
+int git_refdb_reflog_write(git_reflog *reflog);
+
+
 #endif

src/reflog.h

@@ -27,9 +27,14 @@ struct git_reflog_entry {
 };
 
 struct git_reflog {
+	git_refdb *db;
 	char *ref_name;
-	git_repository *owner;
 	git_vector entries;
 };
 
+GIT_INLINE(size_t) reflog_inverse_index(size_t idx, size_t total)
+{
+	return (total - 1) - idx;
+}
+
 #endif /* INCLUDE_reflog_h__ */

src/refs.c

@@ -467,7 +467,7 @@ int git_reference_rename(
 	if (reference_has_log < 0)
 		return reference_has_log;
 
-	if (reference_has_log && (error = git_reflog_rename(ref, new_name)) < 0)
+	if (reference_has_log && (error = git_reflog_rename(git_reference_owner(ref), git_reference_name(ref), new_name)) < 0)
 		return error;
 
 	return 0;

src/revparse.c

@@ -160,7 +160,7 @@ static int retrieve_previously_checked_out_branch_or_revision(git_object **out,
 	if (git_reference_lookup(&ref, repo, GIT_HEAD_FILE) < 0)
 		goto cleanup;
 
-	if (git_reflog_read(&reflog, ref) < 0)
+	if (git_reflog_read(&reflog, repo, GIT_HEAD_FILE) < 0)
 		goto cleanup;
 
 	numentries  = git_reflog_entrycount(reflog);
@@ -208,7 +208,7 @@ static int retrieve_oid_from_reflog(git_oid *oid, git_reference *ref, size_t ide
 	const git_reflog_entry *entry;
 	bool search_by_pos = (identifier <= 100000000);
 
-	if (git_reflog_read(&reflog, ref) < 0)
+	if (git_reflog_read(&reflog, git_reference_owner(ref), git_reference_name(ref)) < 0)
 		return -1;
 
 	numentries = git_reflog_entrycount(reflog);

src/stash.c

@@ -436,14 +436,16 @@ static int update_reflog(
 	const git_signature *stasher,
 	const char *message)
 {
-	git_reference *stash = NULL;
+	git_reference *stash;
 	git_reflog *reflog = NULL;
 	int error;
 
 	if ((error = git_reference_create(&stash, repo, GIT_REFS_STASH_FILE, w_commit_oid, 1)) < 0)
 		goto cleanup;
 
-	if ((error = git_reflog_read(&reflog, stash)) < 0)
+	git_reference_free(stash);
+
+	if ((error = git_reflog_read(&reflog, repo, GIT_REFS_STASH_FILE) < 0))
 		goto cleanup;
 
 	if ((error = git_reflog_append(reflog, w_commit_oid, stasher, message)) < 0)
@@ -453,7 +455,6 @@ static int update_reflog(
 		goto cleanup;
 
 cleanup:
-	git_reference_free(stash);
 	git_reflog_free(reflog);
 	return error;
 }
@@ -599,7 +600,7 @@ int git_stash_foreach(
 	if (error < 0)
 		goto cleanup;
 
-	if ((error = git_reflog_read(&reflog, stash)) < 0)
+	if ((error = git_reflog_read(&reflog, repo, GIT_REFS_STASH_FILE)) < 0)
 		goto cleanup;
 
 	max = git_reflog_entrycount(reflog);
@@ -633,7 +634,7 @@ int git_stash_drop(
 	if ((error = git_reference_lookup(&stash, repo, GIT_REFS_STASH_FILE)) < 0)
 		return error;
 
-	if ((error = git_reflog_read(&reflog, stash)) < 0)
+	if ((error = git_reflog_read(&reflog, repo, GIT_REFS_STASH_FILE)) < 0)
 		goto cleanup;
 
 	max = git_reflog_entrycount(reflog);

tests-clar/refs/reflog/drop.c

@@ -8,15 +8,10 @@ static size_t entrycount;
 
 void test_refs_reflog_drop__initialize(void)
 {
-	git_reference *ref;
-
 	g_repo = cl_git_sandbox_init("testrepo.git");
-	cl_git_pass(git_reference_lookup(&ref, g_repo, "HEAD"));
 
-	git_reflog_read(&g_reflog, ref);
+	git_reflog_read(&g_reflog, g_repo, "HEAD");
 	entrycount = git_reflog_entrycount(g_reflog);
-
-	git_reference_free(ref);
 }
 
 void test_refs_reflog_drop__cleanup(void)
@@ -106,19 +101,15 @@ void test_refs_reflog_drop__can_drop_all_the_entries(void)
 
 void test_refs_reflog_drop__can_persist_deletion_on_disk(void)
 {
-	git_reference *ref;
-
 	cl_assert(entrycount > 2);
 
-	cl_git_pass(git_reference_lookup(&ref, g_repo, g_reflog->ref_name));
 	cl_git_pass(git_reflog_drop(g_reflog, 0, 1));
 	cl_assert_equal_sz(entrycount - 1, git_reflog_entrycount(g_reflog));
 	cl_git_pass(git_reflog_write(g_reflog));
 
 	git_reflog_free(g_reflog);
 
-	git_reflog_read(&g_reflog, ref);
-	git_reference_free(ref);
+	git_reflog_read(&g_reflog, g_repo, "HEAD");
 
 	cl_assert_equal_sz(entrycount - 1, git_reflog_entrycount(g_reflog));
 }

tests-clar/refs/reflog/reflog.c

@@ -50,7 +50,7 @@ void test_refs_reflog_reflog__append_then_read(void)
 
 	cl_git_pass(git_signature_now(&committer, "foo", "foo@bar"));
 
-	cl_git_pass(git_reflog_read(&reflog, ref));
+	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));
@@ -65,7 +65,7 @@ void test_refs_reflog_reflog__append_then_read(void)
 	cl_git_pass(git_reference_lookup(&lookedup_ref, repo2, new_ref));
 
 	/* Read and parse the reflog for this branch */
-	cl_git_pass(git_reflog_read(&reflog, lookedup_ref));
+	cl_git_pass(git_reflog_read(&reflog, repo2, new_ref));
 	cl_assert_equal_i(2, (int)git_reflog_entrycount(reflog));
 
 	entry = git_reflog_entry_byindex(reflog, 1);
@@ -133,21 +133,18 @@ void test_refs_reflog_reflog__reference_has_reflog(void)
 
 void test_refs_reflog_reflog__reading_the_reflog_from_a_reference_with_no_log_returns_an_empty_one(void)
 {
-	git_reference *subtrees;
 	git_reflog *reflog;
+	const char *refname = "refs/heads/subtrees";
 	git_buf subtrees_log_path = GIT_BUF_INIT;
 
-	cl_git_pass(git_reference_lookup(&subtrees, g_repo, "refs/heads/subtrees"));
-
-	git_buf_join_n(&subtrees_log_path, '/', 3, git_repository_path(g_repo), GIT_REFLOG_DIR, git_reference_name(subtrees));
+	git_buf_join_n(&subtrees_log_path, '/', 3, git_repository_path(g_repo), GIT_REFLOG_DIR, refname);
 	cl_assert_equal_i(false, git_path_isfile(git_buf_cstr(&subtrees_log_path)));
 
-	cl_git_pass(git_reflog_read(&reflog, subtrees));
+	cl_git_pass(git_reflog_read(&reflog, g_repo, refname));
 
 	cl_assert_equal_i(0, (int)git_reflog_entrycount(reflog));
 
 	git_reflog_free(reflog);
-	git_reference_free(subtrees);
 	git_buf_free(&subtrees_log_path);
 }
 
@@ -158,7 +155,7 @@ void test_refs_reflog_reflog__cannot_write_a_moved_reflog(void)
 	git_reflog *reflog;
 
 	cl_git_pass(git_reference_lookup(&master, g_repo, "refs/heads/master"));
-	cl_git_pass(git_reflog_read(&reflog, master));
+	cl_git_pass(git_reflog_read(&reflog, g_repo, "refs/heads/master"));
 
 	cl_git_pass(git_reflog_write(reflog));
 
@@ -175,12 +172,6 @@ void test_refs_reflog_reflog__cannot_write_a_moved_reflog(void)
 
 void test_refs_reflog_reflog__renaming_with_an_invalid_name_returns_EINVALIDSPEC(void)
 {
-	git_reference *master;
-
-	cl_git_pass(git_reference_lookup(&master, g_repo, "refs/heads/master"));
-
 	cl_assert_equal_i(GIT_EINVALIDSPEC,
-		git_reflog_rename(master, "refs/heads/Inv@{id"));
-
-	git_reference_free(master);
+			  git_reflog_rename(g_repo, "refs/heads/master", "refs/heads/Inv@{id"));
 }

tests-clar/stash/drop.c

@@ -102,7 +102,7 @@ void test_stash_drop__dropping_an_entry_rewrites_reflog_history(void)
 
 	cl_git_pass(git_reference_lookup(&stash, repo, GIT_REFS_STASH_FILE));
 
-	cl_git_pass(git_reflog_read(&reflog, stash));
+	cl_git_pass(git_reflog_read(&reflog, repo, GIT_REFS_STASH_FILE));
 	entry = git_reflog_entry_byindex(reflog, 1);
 
 	git_oid_cpy(&oid, git_reflog_entry_id_old(entry));
@@ -112,7 +112,7 @@ void test_stash_drop__dropping_an_entry_rewrites_reflog_history(void)
 
 	cl_git_pass(git_stash_drop(repo, 1));
 
-	cl_git_pass(git_reflog_read(&reflog, stash));
+	cl_git_pass(git_reflog_read(&reflog, repo, GIT_REFS_STASH_FILE));
 	entry = git_reflog_entry_byindex(reflog, 0);
 
 	cl_assert_equal_i(0, git_oid_cmp(&oid, git_reflog_entry_id_old(entry)));