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.

1 files changed, 448 insertions, 0 deletions

diff --git a/src/refdb_fs.c b/src/refdb_fs.c
index 0ba711eb7..4d695721d 100644
--- a/src/refdb_fs.c
+++ b/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;