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/refdb_fs.c

@@ -16,12 +16,14 @@
 #include "refdb_fs.h"
 #include "iterator.h"
 #include "sortedcache.h"
+#include "signature.h"
 
 #include <git2/tag.h>
 #include <git2/object.h>
 #include <git2/refdb.h>
 #include <git2/sys/refdb_backend.h>
 #include <git2/sys/refs.h>
+#include <git2/sys/reflog.h>
 
 GIT__USE_STRMAP;
 
@@ -1067,6 +1069,446 @@ static int setup_namespace(git_buf *path, git_repository *repo)
 	return 0;
 }
 
+static int reflog_alloc(git_reflog **reflog, const char *name)
+{
+	git_reflog *log;
+
+	*reflog = NULL;
+
+	log = git__calloc(1, sizeof(git_reflog));
+	GITERR_CHECK_ALLOC(log);
+
+	log->ref_name = git__strdup(name);
+	GITERR_CHECK_ALLOC(log->ref_name);
+
+	if (git_vector_init(&log->entries, 0, NULL) < 0) {
+		git__free(log->ref_name);
+		git__free(log);
+		return -1;
+	}
+
+	*reflog = log;
+
+	return 0;
+}
+
+static int reflog_parse(git_reflog *log, const char *buf, size_t buf_size)
+{
+	const char *ptr;
+	git_reflog_entry *entry;
+
+#define seek_forward(_increase) do { \
+	if (_increase >= buf_size) { \
+		giterr_set(GITERR_INVALID, "Ran out of data while parsing reflog"); \
+		goto fail; \
+	} \
+	buf += _increase; \
+	buf_size -= _increase; \
+	} while (0)
+
+	while (buf_size > GIT_REFLOG_SIZE_MIN) {
+		entry = git__calloc(1, sizeof(git_reflog_entry));
+		GITERR_CHECK_ALLOC(entry);
+
+		entry->committer = git__malloc(sizeof(git_signature));
+		GITERR_CHECK_ALLOC(entry->committer);
+
+		if (git_oid_fromstrn(&entry->oid_old, buf, GIT_OID_HEXSZ) < 0)
+			goto fail;
+		seek_forward(GIT_OID_HEXSZ + 1);
+
+		if (git_oid_fromstrn(&entry->oid_cur, buf, GIT_OID_HEXSZ) < 0)
+			goto fail;
+		seek_forward(GIT_OID_HEXSZ + 1);
+
+		ptr = buf;
+
+		/* Seek forward to the end of the signature. */
+		while (*buf && *buf != '\t' && *buf != '\n')
+			seek_forward(1);
+
+		if (git_signature__parse(entry->committer, &ptr, buf + 1, NULL, *buf) < 0)
+			goto fail;
+
+		if (*buf == '\t') {
+			/* We got a message. Read everything till we reach LF. */
+			seek_forward(1);
+			ptr = buf;
+
+			while (*buf && *buf != '\n')
+				seek_forward(1);
+
+			entry->msg = git__strndup(ptr, buf - ptr);
+			GITERR_CHECK_ALLOC(entry->msg);
+		} else
+			entry->msg = NULL;
+
+		while (*buf && *buf == '\n' && buf_size > 1)
+			seek_forward(1);
+
+		if (git_vector_insert(&log->entries, entry) < 0)
+			goto fail;
+	}
+
+	return 0;
+
+#undef seek_forward
+
+fail:
+	if (entry)
+		git_reflog_entry__free(entry);
+
+	return -1;
+}
+
+static int create_new_reflog_file(const char *filepath)
+{
+	int fd, error;
+
+	if ((error = git_futils_mkpath2file(filepath, GIT_REFLOG_DIR_MODE)) < 0)
+		return error;
+
+	if ((fd = p_open(filepath,
+			O_WRONLY | O_CREAT | O_TRUNC,
+			GIT_REFLOG_FILE_MODE)) < 0)
+		return -1;
+
+	return p_close(fd);
+}
+
+GIT_INLINE(int) retrieve_reflog_path(git_buf *path, git_repository *repo, const char *name)
+{
+	return git_buf_join_n(path, '/', 3, repo->path_repository, GIT_REFLOG_DIR, name);
+}
+
+static int refdb_reflog_fs__read(git_reflog **out, git_refdb_backend *_backend, const char *name)
+{
+	int error = -1;
+	git_buf log_path = GIT_BUF_INIT;
+	git_buf log_file = GIT_BUF_INIT;
+	git_reflog *log = NULL;
+	git_repository *repo;
+	refdb_fs_backend *backend;
+
+	assert(out && _backend && name);
+
+	backend = (refdb_fs_backend *) _backend;
+	repo = backend->repo;
+
+	if (reflog_alloc(&log, name) < 0)
+		return -1;
+
+	if (retrieve_reflog_path(&log_path, repo, name) < 0)
+		goto cleanup;
+
+	error = git_futils_readbuffer(&log_file, git_buf_cstr(&log_path));
+	if (error < 0 && error != GIT_ENOTFOUND)
+		goto cleanup;
+
+	if ((error == GIT_ENOTFOUND) &&
+		((error = create_new_reflog_file(git_buf_cstr(&log_path))) < 0))
+		goto cleanup;
+ 
+	if ((error = reflog_parse(log,
+		git_buf_cstr(&log_file), git_buf_len(&log_file))) < 0)
+		goto cleanup;
+
+	*out = log;
+	goto success;
+
+cleanup:
+	git_reflog_free(log);
+
+success:
+	git_buf_free(&log_file);
+	git_buf_free(&log_path);
+
+	return error;
+}
+
+static int serialize_reflog_entry(
+	git_buf *buf,
+	const git_oid *oid_old,
+	const git_oid *oid_new,
+	const git_signature *committer,
+	const char *msg)
+{
+	char raw_old[GIT_OID_HEXSZ+1];
+	char raw_new[GIT_OID_HEXSZ+1];
+
+	git_oid_tostr(raw_old, GIT_OID_HEXSZ+1, oid_old);
+	git_oid_tostr(raw_new, GIT_OID_HEXSZ+1, oid_new);
+
+	git_buf_clear(buf);
+
+	git_buf_puts(buf, raw_old);
+	git_buf_putc(buf, ' ');
+	git_buf_puts(buf, raw_new);
+
+	git_signature__writebuf(buf, " ", committer);
+
+	/* drop trailing LF */
+	git_buf_rtrim(buf);
+
+	if (msg) {
+		git_buf_putc(buf, '\t');
+		git_buf_puts(buf, msg);
+	}
+
+	git_buf_putc(buf, '\n');
+
+	return git_buf_oom(buf);
+}
+
+static int refdb_reflog_fs__write(git_refdb_backend *_backend, git_reflog *reflog)
+{
+	int error = -1;
+	unsigned int i;
+	git_reflog_entry *entry;
+	git_repository *repo;
+	refdb_fs_backend *backend;
+	git_buf log_path = GIT_BUF_INIT;
+	git_buf log = GIT_BUF_INIT;
+	git_filebuf fbuf = GIT_FILEBUF_INIT;
+
+	assert(_backend && reflog);
+
+	backend = (refdb_fs_backend *) _backend;
+	repo = backend->repo;
+
+	if (retrieve_reflog_path(&log_path, repo, reflog->ref_name) < 0)
+		return -1;
+
+	if (!git_path_isfile(git_buf_cstr(&log_path))) {
+		giterr_set(GITERR_INVALID,
+			"Log file for reference '%s' doesn't exist.", reflog->ref_name);
+		goto cleanup;
+	}
+
+	if ((error = git_filebuf_open(&fbuf, git_buf_cstr(&log_path), 0)) < 0)
+		goto cleanup;
+
+	git_vector_foreach(&reflog->entries, i, entry) {
+		if (serialize_reflog_entry(&log, &(entry->oid_old), &(entry->oid_cur), entry->committer, entry->msg) < 0)
+			goto cleanup;
+
+		if ((error = git_filebuf_write(&fbuf, log.ptr, log.size)) < 0)
+			goto cleanup;
+	}
+
+	error = git_filebuf_commit(&fbuf, GIT_REFLOG_FILE_MODE);
+	goto success;
+
+cleanup:
+	git_filebuf_cleanup(&fbuf);
+
+success:
+	git_buf_free(&log);
+	git_buf_free(&log_path);
+	return error;
+}
+
+static int refdb_reflog_fs__append(git_refdb_backend *_backend, git_reflog *reflog,
+		      const git_oid *new_oid, const git_signature *committer, const char *msg)
+{
+	git_reflog_entry *entry;
+	const git_reflog_entry *previous;
+	const char *newline;
+
+	assert(_backend && reflog && new_oid && committer);
+
+	entry = git__calloc(1, sizeof(git_reflog_entry));
+	GITERR_CHECK_ALLOC(entry);
+
+	if ((entry->committer = git_signature_dup(committer)) == NULL)
+		goto cleanup;
+
+	if (msg != NULL) {
+		if ((entry->msg = git__strdup(msg)) == NULL)
+			goto cleanup;
+
+		newline = strchr(msg, '\n');
+
+		if (newline) {
+			if (newline[1] != '\0') {
+				giterr_set(GITERR_INVALID, "Reflog message cannot contain newline");
+				goto cleanup;
+			}
+
+			entry->msg[newline - msg] = '\0';
+		}
+	}
+
+	previous = git_reflog_entry_byindex(reflog, 0);
+
+	if (previous == NULL)
+		git_oid_fromstr(&entry->oid_old, GIT_OID_HEX_ZERO);
+	else
+		git_oid_cpy(&entry->oid_old, &previous->oid_cur);
+
+	git_oid_cpy(&entry->oid_cur, new_oid);
+
+	if (git_vector_insert(&reflog->entries, entry) < 0)
+		goto cleanup;
+
+	return 0;
+
+cleanup:
+	git_reflog_entry__free(entry);
+	return -1;
+}
+
+static int refdb_reflog_fs__rename(git_refdb_backend *_backend, const char *old_name, const char *new_name)
+{
+	int error = 0, fd;
+	git_buf old_path = GIT_BUF_INIT;
+	git_buf new_path = GIT_BUF_INIT;
+	git_buf temp_path = GIT_BUF_INIT;
+	git_buf normalized = GIT_BUF_INIT;
+	git_repository *repo;
+	refdb_fs_backend *backend;
+
+	assert(_backend && old_name && new_name);
+
+	backend = (refdb_fs_backend *) _backend;
+	repo = backend->repo;
+
+	if ((error = git_reference__normalize_name(
+		&normalized, new_name, GIT_REF_FORMAT_ALLOW_ONELEVEL)) < 0)
+			return error;
+
+	if (git_buf_joinpath(&temp_path, repo->path_repository, GIT_REFLOG_DIR) < 0)
+		return -1;
+
+	if (git_buf_joinpath(&old_path, git_buf_cstr(&temp_path), old_name) < 0)
+		return -1;
+
+	if (git_buf_joinpath(&new_path, git_buf_cstr(&temp_path), git_buf_cstr(&normalized)) < 0)
+		return -1;
+
+	/*
+	 * Move the reflog to a temporary place. This two-phase renaming is required
+	 * in order to cope with funny renaming use cases when one tries to move a reference
+	 * to a partially colliding namespace:
+	 *  - a/b -> a/b/c
+	 *  - a/b/c/d -> a/b/c
+	 */
+	if (git_buf_joinpath(&temp_path, git_buf_cstr(&temp_path), "temp_reflog") < 0)
+		return -1;
+
+	if ((fd = git_futils_mktmp(&temp_path, git_buf_cstr(&temp_path))) < 0) {
+		error = -1;
+		goto cleanup;
+	}
+
+	p_close(fd);
+
+	if (p_rename(git_buf_cstr(&old_path), git_buf_cstr(&temp_path)) < 0) {
+		giterr_set(GITERR_OS, "Failed to rename reflog for %s", new_name);
+		error = -1;
+		goto cleanup;
+	}
+
+	if (git_path_isdir(git_buf_cstr(&new_path)) && 
+		(git_futils_rmdir_r(git_buf_cstr(&new_path), NULL, GIT_RMDIR_SKIP_NONEMPTY) < 0)) {
+		error = -1;
+		goto cleanup;
+	}
+
+	if (git_futils_mkpath2file(git_buf_cstr(&new_path), GIT_REFLOG_DIR_MODE) < 0) {
+		error = -1;
+		goto cleanup;
+	}
+
+	if (p_rename(git_buf_cstr(&temp_path), git_buf_cstr(&new_path)) < 0) {
+		giterr_set(GITERR_OS, "Failed to rename reflog for %s", new_name);
+		error = -1;
+	}
+
+cleanup:
+	git_buf_free(&temp_path);
+	git_buf_free(&old_path);
+	git_buf_free(&new_path);
+	git_buf_free(&normalized);
+
+	return error;
+}
+
+static int refdb_reflog_fs__drop(git_refdb_backend *_backend, git_reflog *reflog,
+				 size_t idx, int rewrite_previous_entry)
+{
+	size_t entrycount;
+	git_reflog_entry *entry, *previous;
+
+	assert(_backend && reflog);
+
+	entrycount = git_reflog_entrycount(reflog);
+
+	entry = (git_reflog_entry *)git_reflog_entry_byindex(reflog, idx);
+
+	if (entry == NULL) {
+		giterr_set(GITERR_REFERENCE, "No reflog entry at index "PRIuZ, idx);
+		return GIT_ENOTFOUND;
+	}
+
+	git_reflog_entry__free(entry);
+
+	if (git_vector_remove(
+			&reflog->entries, reflog_inverse_index(idx, entrycount)) < 0)
+		return -1;
+
+	if (!rewrite_previous_entry)
+		return 0;
+
+	/* No need to rewrite anything when removing the most recent entry */
+	if (idx == 0)
+		return 0;
+
+	/* Have the latest entry just been dropped? */
+	if (entrycount == 1)
+		return 0;
+
+	entry = (git_reflog_entry *)git_reflog_entry_byindex(reflog, idx - 1);
+
+	/* If the oldest entry has just been removed... */
+	if (idx == entrycount - 1) {
+		/* ...clear the oid_old member of the "new" oldest entry */
+		if (git_oid_fromstr(&entry->oid_old, GIT_OID_HEX_ZERO) < 0)
+			return -1;
+
+		return 0;
+	}
+
+	previous = (git_reflog_entry *)git_reflog_entry_byindex(reflog, idx);
+	git_oid_cpy(&entry->oid_old, &previous->oid_cur);
+
+	return 0;
+}
+
+static int refdb_reflog_fs__delete(git_refdb_backend *_backend, const char *name)
+{
+	int error;
+	git_buf path = GIT_BUF_INIT;
+
+	git_repository *repo;
+	refdb_fs_backend *backend;
+
+	assert(_backend && name);
+
+	backend = (refdb_fs_backend *) _backend;
+	repo = backend->repo;
+
+	error = retrieve_reflog_path(&path, repo, name);
+
+	if (!error && git_path_exists(path.ptr))
+		error = p_unlink(path.ptr);
+
+	git_buf_free(&path);
+
+	return error;
+
+}
+
 int git_refdb_backend_fs(
 	git_refdb_backend **backend_out,
 	git_repository *repository)
@@ -1100,6 +1542,12 @@ int git_refdb_backend_fs(
 	backend->parent.rename = &refdb_fs_backend__rename;
 	backend->parent.compress = &refdb_fs_backend__compress;
 	backend->parent.free = &refdb_fs_backend__free;
+	backend->parent.reflog_read = &refdb_reflog_fs__read;
+	backend->parent.reflog_write = &refdb_reflog_fs__write;
+	backend->parent.reflog_append = &refdb_reflog_fs__append;
+	backend->parent.reflog_rename = &refdb_reflog_fs__rename;
+	backend->parent.reflog_drop = &refdb_reflog_fs__drop;
+	backend->parent.reflog_delete = &refdb_reflog_fs__delete;
 
 	*backend_out = (git_refdb_backend *)backend;
 	return 0;

src/reflog.c

@@ -9,82 +9,16 @@
 #include "repository.h"
 #include "filebuf.h"
 #include "signature.h"
+#include "refdb.h"
 
-static int reflog_init(git_reflog **reflog, const git_reference *ref)
-{
-	git_reflog *log;
-
-	*reflog = NULL;
-
-	log = git__calloc(1, sizeof(git_reflog));
-	GITERR_CHECK_ALLOC(log);
-
-	log->ref_name = git__strdup(ref->name);
-	GITERR_CHECK_ALLOC(log->ref_name);
-
-	if (git_vector_init(&log->entries, 0, NULL) < 0) {
-		git__free(log->ref_name);
-		git__free(log);
-		return -1;
-	}
-
-	log->owner = git_reference_owner(ref);
-	*reflog = log;
-
-	return 0;
-}
+#include <git2/sys/refdb_backend.h>
 
-static int serialize_reflog_entry(
-	git_buf *buf,
-	const git_oid *oid_old,
-	const git_oid *oid_new,
-	const git_signature *committer,
-	const char *msg)
+git_reflog_entry *git_reflog_entry__alloc(void)
 {
-	char raw_old[GIT_OID_HEXSZ+1];
-	char raw_new[GIT_OID_HEXSZ+1];
-
-	git_oid_tostr(raw_old, GIT_OID_HEXSZ+1, oid_old);
-	git_oid_tostr(raw_new, GIT_OID_HEXSZ+1, oid_new);
-
-	git_buf_clear(buf);
-
-	git_buf_puts(buf, raw_old);
-	git_buf_putc(buf, ' ');
-	git_buf_puts(buf, raw_new);
-
-	git_signature__writebuf(buf, " ", committer);
-
-	/* drop trailing LF */
-	git_buf_rtrim(buf);
-
-	if (msg) {
-		git_buf_putc(buf, '\t');
-		git_buf_puts(buf, msg);
-	}
-
-	git_buf_putc(buf, '\n');
-
-	return git_buf_oom(buf);
+	return git__calloc(1, sizeof(git_reflog_entry));
 }
 
-static int reflog_entry_new(git_reflog_entry **entry)
-{
-	git_reflog_entry *e;
-
-	assert(entry);
-
-	e = git__malloc(sizeof(git_reflog_entry));
-	GITERR_CHECK_ALLOC(e);
-
-	memset(e, 0, sizeof(git_reflog_entry));
-
-	*entry = e;
-
-	return 0;
-}
-
-static void reflog_entry_free(git_reflog_entry *entry)
+void git_reflog_entry__free(git_reflog_entry *entry)
 {
 	git_signature_free(entry->committer);
 
@@ -92,75 +26,6 @@ static void reflog_entry_free(git_reflog_entry *entry)
 	git__free(entry);
 }
 
-static int reflog_parse(git_reflog *log, const char *buf, size_t buf_size)
-{
-	const char *ptr;
-	git_reflog_entry *entry;
-
-#define seek_forward(_increase) do { \
-	if (_increase >= buf_size) { \
-		giterr_set(GITERR_INVALID, "Ran out of data while parsing reflog"); \
-		goto fail; \
-	} \
-	buf += _increase; \
-	buf_size -= _increase; \
-	} while (0)
-
-	while (buf_size > GIT_REFLOG_SIZE_MIN) {
-		if (reflog_entry_new(&entry) < 0)
-			return -1;
-
-		entry->committer = git__malloc(sizeof(git_signature));
-		GITERR_CHECK_ALLOC(entry->committer);
-
-		if (git_oid_fromstrn(&entry->oid_old, buf, GIT_OID_HEXSZ) < 0)
-			goto fail;
-		seek_forward(GIT_OID_HEXSZ + 1);
-
-		if (git_oid_fromstrn(&entry->oid_cur, buf, GIT_OID_HEXSZ) < 0)
-			goto fail;
-		seek_forward(GIT_OID_HEXSZ + 1);
-
-		ptr = buf;
-
-		/* Seek forward to the end of the signature. */
-		while (*buf && *buf != '\t' && *buf != '\n')
-			seek_forward(1);
-
-		if (git_signature__parse(entry->committer, &ptr, buf + 1, NULL, *buf) < 0)
-			goto fail;
-
-		if (*buf == '\t') {
-			/* We got a message. Read everything till we reach LF. */
-			seek_forward(1);
-			ptr = buf;
-
-			while (*buf && *buf != '\n')
-				seek_forward(1);
-
-			entry->msg = git__strndup(ptr, buf - ptr);
-			GITERR_CHECK_ALLOC(entry->msg);
-		} else
-			entry->msg = NULL;
-
-		while (*buf && *buf == '\n' && buf_size > 1)
-			seek_forward(1);
-
-		if (git_vector_insert(&log->entries, entry) < 0)
-			goto fail;
-	}
-
-	return 0;
-
-#undef seek_forward
-
-fail:
-	if (entry)
-		reflog_entry_free(entry);
-
-	return -1;
-}
-
 void git_reflog_free(git_reflog *reflog)
 {
 	size_t i;
@@ -169,10 +34,13 @@ void git_reflog_free(git_reflog *reflog)
 	if (reflog == NULL)
 		return;
 
+	if (reflog->db)
+		GIT_REFCOUNT_DEC(reflog->db, git_refdb__free);
+
 	for (i=0; i < reflog->entries.length; i++) {
 		entry = git_vector_get(&reflog->entries, i);
 
-		reflog_entry_free(entry);
+		git_reflog_entry__free(entry);
 	}
 
 	git_vector_free(&reflog->entries);
@@ -180,247 +48,61 @@ void git_reflog_free(git_reflog *reflog)
 	git__free(reflog);
 }
 
-static int retrieve_reflog_path(git_buf *path, const git_reference *ref)
+int git_reflog_read(git_reflog **reflog, git_repository *repo,  const char *name)
 {
-	return git_buf_join_n(path, '/', 3,
-		git_reference_owner(ref)->path_repository, GIT_REFLOG_DIR, ref->name);
-}
+	git_refdb *refdb;
+	int error;
 
-static int create_new_reflog_file(const char *filepath)
-{
-	int fd, error;
+	assert(reflog && repo && name);
 
-	if ((error = git_futils_mkpath2file(filepath, GIT_REFLOG_DIR_MODE)) < 0)
+	if ((error = git_repository_refdb__weakptr(&refdb, repo)) < 0)
 		return error;
 
-	if ((fd = p_open(filepath,
-			O_WRONLY | O_CREAT | O_TRUNC,
-			GIT_REFLOG_FILE_MODE)) < 0)
-		return -1;
-
-	return p_close(fd);
-}
-
-int git_reflog_read(git_reflog **reflog, const git_reference *ref)
-{
-	int error = -1;
-	git_buf log_path = GIT_BUF_INIT;
-	git_buf log_file = GIT_BUF_INIT;
-	git_reflog *log = NULL;
-
-	assert(reflog && ref);
-
-	*reflog = NULL;
-
-	if (reflog_init(&log, ref) < 0)
-		return -1;
-
-	if (retrieve_reflog_path(&log_path, ref) < 0)
-		goto cleanup;
-
-	error = git_futils_readbuffer(&log_file, git_buf_cstr(&log_path));
-	if (error < 0 && error != GIT_ENOTFOUND)
-		goto cleanup;
-
-	if ((error == GIT_ENOTFOUND) &&
-		((error = create_new_reflog_file(git_buf_cstr(&log_path))) < 0))
-		goto cleanup;
-
-	if ((error = reflog_parse(log,
-		git_buf_cstr(&log_file), git_buf_len(&log_file))) < 0)
-		goto cleanup;
-
-	*reflog = log;
-	goto success;
-
-cleanup:
-	git_reflog_free(log);
-
-success:
-	git_buf_free(&log_file);
-	git_buf_free(&log_path);
-
-	return error;
+	return git_refdb_reflog_read(reflog, refdb, name);
 }
 
 int git_reflog_write(git_reflog *reflog)
 {
-	int error = -1;
-	unsigned int i;
-	git_reflog_entry *entry;
-	git_buf log_path = GIT_BUF_INIT;
-	git_buf log = GIT_BUF_INIT;
-	git_filebuf fbuf = GIT_FILEBUF_INIT;
-
-	assert(reflog);
-
-	if (git_buf_join_n(&log_path, '/', 3,
-		git_repository_path(reflog->owner), GIT_REFLOG_DIR, reflog->ref_name) < 0)
-		return -1;
-
-	if (!git_path_isfile(git_buf_cstr(&log_path))) {
-		giterr_set(GITERR_INVALID,
-			"Log file for reference '%s' doesn't exist.", reflog->ref_name);
-		goto cleanup;
-	}
-
-	if ((error = git_filebuf_open(&fbuf, git_buf_cstr(&log_path), 0)) < 0)
-		goto cleanup;
+	git_refdb *db;
 
-	git_vector_foreach(&reflog->entries, i, entry) {
-		if (serialize_reflog_entry(&log, &(entry->oid_old), &(entry->oid_cur), entry->committer, entry->msg) < 0)
-			goto cleanup;
+	assert(reflog && reflog->db);
 
-		if ((error = git_filebuf_write(&fbuf, log.ptr, log.size)) < 0)
-			goto cleanup;
-	}
-
-	error = git_filebuf_commit(&fbuf, GIT_REFLOG_FILE_MODE);
-	goto success;
-
-cleanup:
-	git_filebuf_cleanup(&fbuf);
-
-success:
-	git_buf_free(&log);
-	git_buf_free(&log_path);
-	return error;
+	db = reflog->db;
+	return db->backend->reflog_write(db->backend, reflog);
 }
 
 int git_reflog_append(git_reflog *reflog, const git_oid *new_oid,
 				const git_signature *committer, const char *msg)
 {
-	git_reflog_entry *entry;
-	const git_reflog_entry *previous;
-	const char *newline;
-
-	assert(reflog && new_oid && committer);
-
-	if (reflog_entry_new(&entry) < 0)
-		return -1;
-
-	if ((entry->committer = git_signature_dup(committer)) == NULL)
-		goto cleanup;
+	git_refdb *db;
 
-	if (msg != NULL) {
-		if ((entry->msg = git__strdup(msg)) == NULL)
-			goto cleanup;
+	assert(reflog && reflog->db && new_oid && committer);
 
-		newline = strchr(msg, '\n');
+	db = reflog->db;
 
-		if (newline) {
-			if (newline[1] != '\0') {
-				giterr_set(GITERR_INVALID, "Reflog message cannot contain newline");
-				goto cleanup;
-			}
-
-			entry->msg[newline - msg] = '\0';
-		}
-	}
-
-	previous = git_reflog_entry_byindex(reflog, 0);
-
-	if (previous == NULL)
-		git_oid_fromstr(&entry->oid_old, GIT_OID_HEX_ZERO);
-	else
-		git_oid_cpy(&entry->oid_old, &previous->oid_cur);
-
-	git_oid_cpy(&entry->oid_cur, new_oid);
-
-	if (git_vector_insert(&reflog->entries, entry) < 0)
-		goto cleanup;
-
-	return 0;
-
-cleanup:
-	reflog_entry_free(entry);
-	return -1;
+	return db->backend->reflog_append(db->backend, reflog, new_oid, committer, msg);
 }
 
-int git_reflog_rename(git_reference *ref, const char *new_name)
+int git_reflog_rename(git_repository *repo, const char *old_name, const char *new_name)
 {
-	int error = 0, fd;
-	git_buf old_path = GIT_BUF_INIT;
-	git_buf new_path = GIT_BUF_INIT;
-	git_buf temp_path = GIT_BUF_INIT;
-	git_buf normalized = GIT_BUF_INIT;
-
-	assert(ref && new_name);
-
-	if ((error = git_reference__normalize_name(
-		&normalized, new_name, GIT_REF_FORMAT_ALLOW_ONELEVEL)) < 0)
-			return error;
-
-	if (git_buf_joinpath(&temp_path, git_reference_owner(ref)->path_repository, GIT_REFLOG_DIR) < 0)
-		return -1;
-
-	if (git_buf_joinpath(&old_path, git_buf_cstr(&temp_path), ref->name) < 0)
-		return -1;
-
-	if (git_buf_joinpath(&new_path, git_buf_cstr(&temp_path), git_buf_cstr(&normalized)) < 0)
-		return -1;
+	git_refdb *refdb;
+	int error;
 
-	/*
-	 * Move the reflog to a temporary place. This two-phase renaming is required
-	 * in order to cope with funny renaming use cases when one tries to move a reference
-	 * to a partially colliding namespace:
-	 *  - a/b -> a/b/c
-	 *  - a/b/c/d -> a/b/c
-	 */
-	if (git_buf_joinpath(&temp_path, git_buf_cstr(&temp_path), "temp_reflog") < 0)
+	if ((error = git_repository_refdb__weakptr(&refdb, repo)) < 0)
 		return -1;
 
-	if ((fd = git_futils_mktmp(&temp_path, git_buf_cstr(&temp_path))) < 0) {
-		error = -1;
-		goto cleanup;
-	}
-
-	p_close(fd);
-
-	if (p_rename(git_buf_cstr(&old_path), git_buf_cstr(&temp_path)) < 0) {
-		giterr_set(GITERR_OS, "Failed to rename reflog for %s", new_name);
-		error = -1;
-		goto cleanup;
-	}
-
-	if (git_path_isdir(git_buf_cstr(&new_path)) && 
-		(git_futils_rmdir_r(git_buf_cstr(&new_path), NULL, GIT_RMDIR_SKIP_NONEMPTY) < 0)) {
-		error = -1;
-		goto cleanup;
-	}
-
-	if (git_futils_mkpath2file(git_buf_cstr(&new_path), GIT_REFLOG_DIR_MODE) < 0) {
-		error = -1;
-		goto cleanup;
-	}
-
-	if (p_rename(git_buf_cstr(&temp_path), git_buf_cstr(&new_path)) < 0) {
-		giterr_set(GITERR_OS, "Failed to rename reflog for %s", new_name);
-		error = -1;
-	}
-
-cleanup:
-	git_buf_free(&temp_path);
-	git_buf_free(&old_path);
-	git_buf_free(&new_path);
-	git_buf_free(&normalized);
-
-	return error;
+	return refdb->backend->reflog_rename(refdb->backend, old_name, new_name);
 }
 
-int git_reflog_delete(git_reference *ref)
+int git_reflog_delete(git_repository *repo, const char *name)
 {
+	git_refdb *refdb;
 	int error;
-	git_buf path = GIT_BUF_INIT;
-
-	error = retrieve_reflog_path(&path, ref);
 
-	if (!error && git_path_exists(path.ptr))
-		error = p_unlink(path.ptr);
-
-	git_buf_free(&path);
+	if ((error = git_repository_refdb__weakptr(&refdb, repo)) < 0)
+		return -1;
 
-	return error;
+	return refdb->backend->reflog_delete(refdb->backend, name);
 }
 
 size_t git_reflog_entrycount(git_reflog *reflog)
@@ -429,11 +111,6 @@ size_t git_reflog_entrycount(git_reflog *reflog)
 	return reflog->entries.length;
 }
 
-GIT_INLINE(size_t) reflog_inverse_index(size_t idx, size_t total)
-{
-	return (total - 1) - idx;
-}
-
 const git_reflog_entry * git_reflog_entry_byindex(git_reflog *reflog, size_t idx)
 {
 	assert(reflog);
@@ -474,50 +151,10 @@ int git_reflog_drop(
 	size_t idx,
 	int rewrite_previous_entry)
 {
-	size_t entrycount;
-	git_reflog_entry *entry, *previous;
-
-	assert(reflog);
-
-	entrycount = git_reflog_entrycount(reflog);
-
-	entry = (git_reflog_entry *)git_reflog_entry_byindex(reflog, idx);
-
-	if (entry == NULL) {
-		giterr_set(GITERR_REFERENCE, "No reflog entry at index %"PRIuZ, idx);
-		return GIT_ENOTFOUND;
-	}
-
-	reflog_entry_free(entry);
-
-	if (git_vector_remove(
-			&reflog->entries, reflog_inverse_index(idx, entrycount)) < 0)
-		return -1;
-
-	if (!rewrite_previous_entry)
-		return 0;
-
-	/* No need to rewrite anything when removing the most recent entry */
-	if (idx == 0)
-		return 0;
-
-	/* Have the latest entry just been dropped? */
-	if (entrycount == 1)
-		return 0;
-
-	entry = (git_reflog_entry *)git_reflog_entry_byindex(reflog, idx - 1);
-
-	/* If the oldest entry has just been removed... */
-	if (idx == entrycount - 1) {
-		/* ...clear the oid_old member of the "new" oldest entry */
-		if (git_oid_fromstr(&entry->oid_old, GIT_OID_HEX_ZERO) < 0)
-			return -1;
-
-		return 0;
-	}
+	git_refdb *db;
 
-	previous = (git_reflog_entry *)git_reflog_entry_byindex(reflog, idx);
-	git_oid_cpy(&entry->oid_old, &previous->oid_cur);
+	assert(reflog && reflog->db);
 
-	return 0;
+	db = reflog->db;
+	return db->backend->reflog_drop(db->backend, reflog, idx, rewrite_previous_entry);
 }

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)));