refdb_fs.c 46.9 KB
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/*
 * 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.
 */

#include "refs.h"
#include "hash.h"
#include "repository.h"
#include "fileops.h"
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#include "filebuf.h"
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#include "pack.h"
#include "reflog.h"
#include "refdb.h"
#include "refdb_fs.h"
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#include "iterator.h"
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#include "sortedcache.h"
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#include "signature.h"
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#include <git2/tag.h>
#include <git2/object.h>
#include <git2/refdb.h>
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#include <git2/branch.h>
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#include <git2/sys/refdb_backend.h>
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#include <git2/sys/refs.h>
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#include <git2/sys/reflog.h>
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GIT__USE_STRMAP
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#define DEFAULT_NESTING_LEVEL	5
#define MAX_NESTING_LEVEL		10

enum {
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	PACKREF_HAS_PEEL = 1,
	PACKREF_WAS_LOOSE = 2,
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	PACKREF_CANNOT_PEEL = 4,
	PACKREF_SHADOWED = 8,
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};

enum {
	PEELING_NONE = 0,
	PEELING_STANDARD,
	PEELING_FULL
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};

struct packref {
	git_oid oid;
	git_oid peel;
	char flags;
	char name[GIT_FLEX_ARRAY];
};

typedef struct refdb_fs_backend {
	git_refdb_backend parent;

	git_repository *repo;
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	char *path;
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	git_sortedcache *refcache;
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	int peeling_mode;
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	git_iterator_flag_t iterator_flags;
	uint32_t direach_flags;
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} refdb_fs_backend;

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static int packref_cmp(const void *a_, const void *b_)
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{
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	const struct packref *a = a_, *b = b_;
	return strcmp(a->name, b->name);
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}

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static int packed_reload(refdb_fs_backend *backend)
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{
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	int error;
	git_buf packedrefs = GIT_BUF_INIT;
	char *scan, *eof, *eol;
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	if (!backend->path)
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		return 0;

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	error = git_sortedcache_lockandload(backend->refcache, &packedrefs);
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	/*
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	 * If we can't find the packed-refs, clear table and return.
	 * Any other error just gets passed through.
	 * If no error, and file wasn't changed, just return.
	 * Anything else means we need to refresh the packed refs.
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	 */
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	if (error <= 0) {
		if (error == GIT_ENOTFOUND) {
			git_sortedcache_clear(backend->refcache, true);
			giterr_clear();
			error = 0;
		}
		return error;
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	}

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	/* At this point, refresh the packed refs from the loaded buffer. */
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	git_sortedcache_clear(backend->refcache, false);
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	scan = (char *)packedrefs.ptr;
	eof  = scan + packedrefs.size;
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	backend->peeling_mode = PEELING_NONE;

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	if (*scan == '#') {
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		static const char *traits_header = "# pack-refs with: ";
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		if (git__prefixcmp(scan, traits_header) == 0) {
			scan += strlen(traits_header);
			eol = strchr(scan, '\n');
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			if (!eol)
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				goto parse_failed;
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			*eol = '\0';
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			if (strstr(scan, " fully-peeled ") != NULL) {
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				backend->peeling_mode = PEELING_FULL;
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			} else if (strstr(scan, " peeled ") != NULL) {
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				backend->peeling_mode = PEELING_STANDARD;
			}

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			scan = eol + 1;
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		}
	}

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	while (scan < eof && *scan == '#') {
		if (!(eol = strchr(scan, '\n')))
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			goto parse_failed;
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		scan = eol + 1;
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	}

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	while (scan < eof) {
		struct packref *ref;
		git_oid oid;

		/* parse "<OID> <refname>\n" */
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		if (git_oid_fromstr(&oid, scan) < 0)
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			goto parse_failed;
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		scan += GIT_OID_HEXSZ;
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		if (*scan++ != ' ')
			goto parse_failed;
		if (!(eol = strchr(scan, '\n')))
			goto parse_failed;
		*eol = '\0';
		if (eol[-1] == '\r')
			eol[-1] = '\0';
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		if (git_sortedcache_upsert((void **)&ref, backend->refcache, scan) < 0)
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			goto parse_failed;
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		scan = eol + 1;

		git_oid_cpy(&ref->oid, &oid);

		/* look for optional "^<OID>\n" */

		if (*scan == '^') {
			if (git_oid_fromstr(&oid, scan + 1) < 0)
				goto parse_failed;
			scan += GIT_OID_HEXSZ + 1;

			if (scan < eof) {
				if (!(eol = strchr(scan, '\n')))
					goto parse_failed;
				scan = eol + 1;
			}

			git_oid_cpy(&ref->peel, &oid);
			ref->flags |= PACKREF_HAS_PEEL;
		}
		else if (backend->peeling_mode == PEELING_FULL ||
				(backend->peeling_mode == PEELING_STANDARD &&
				 git__prefixcmp(ref->name, GIT_REFS_TAGS_DIR) == 0))
			ref->flags |= PACKREF_CANNOT_PEEL;
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	}

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	git_sortedcache_wunlock(backend->refcache);
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	git_buf_free(&packedrefs);

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	return 0;

parse_failed:
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	giterr_set(GITERR_REFERENCE, "Corrupted packed references file");

	git_sortedcache_clear(backend->refcache, false);
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	git_sortedcache_wunlock(backend->refcache);
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	git_buf_free(&packedrefs);

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	return -1;
}

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static int loose_parse_oid(
	git_oid *oid, const char *filename, git_buf *file_content)
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{
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	const char *str = git_buf_cstr(file_content);
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	if (git_buf_len(file_content) < GIT_OID_HEXSZ)
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		goto corrupted;

	/* we need to get 40 OID characters from the file */
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	if (git_oid_fromstr(oid, str) < 0)
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		goto corrupted;

	/* If the file is longer than 40 chars, the 41st must be a space */
	str += GIT_OID_HEXSZ;
	if (*str == '\0' || git__isspace(*str))
		return 0;

corrupted:
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	giterr_set(GITERR_REFERENCE, "Corrupted loose reference file: %s", filename);
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	return -1;
}

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static int loose_readbuffer(git_buf *buf, const char *base, const char *path)
{
	int error;

	/* build full path to file */
	if ((error = git_buf_joinpath(buf, base, path)) < 0 ||
		(error = git_futils_readbuffer(buf, buf->ptr)) < 0)
		git_buf_free(buf);

	return error;
}

static int loose_lookup_to_packfile(refdb_fs_backend *backend, const char *name)
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{
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	int error = 0;
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	git_buf ref_file = GIT_BUF_INIT;
	struct packref *ref = NULL;
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	git_oid oid;
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	/* if we fail to load the loose reference, assume someone changed
	 * the filesystem under us and skip it...
	 */
	if (loose_readbuffer(&ref_file, backend->path, name) < 0) {
		giterr_clear();
		goto done;
	}
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	/* skip symbolic refs */
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	if (!git__prefixcmp(git_buf_cstr(&ref_file), GIT_SYMREF))
		goto done;
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	/* parse OID from file */
	if ((error = loose_parse_oid(&oid, name, &ref_file)) < 0)
		goto done;
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	git_sortedcache_wlock(backend->refcache);
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	if (!(error = git_sortedcache_upsert(
			(void **)&ref, backend->refcache, name))) {
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		git_oid_cpy(&ref->oid, &oid);
		ref->flags = PACKREF_WAS_LOOSE;
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	}

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	git_sortedcache_wunlock(backend->refcache);
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done:
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	git_buf_free(&ref_file);
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	return error;
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}

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static int _dirent_loose_load(void *payload, git_buf *full_path)
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{
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	refdb_fs_backend *backend = payload;
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	const char *file_path;

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	if (git__suffixcmp(full_path->ptr, ".lock") == 0)
		return 0;

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	if (git_path_isdir(full_path->ptr)) {
		int error = git_path_direach(
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			full_path, backend->direach_flags, _dirent_loose_load, backend);
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		/* Race with the filesystem, ignore it */
		if (error == GIT_ENOTFOUND) {
			giterr_clear();
			return 0;
		}

		return error;
	}
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	file_path = full_path->ptr + strlen(backend->path);
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	return loose_lookup_to_packfile(backend, file_path);
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}

/*
 * Load all the loose references from the repository
 * into the in-memory Packfile, and build a vector with
 * all the references so it can be written back to
 * disk.
 */
static int packed_loadloose(refdb_fs_backend *backend)
{
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	int error;
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	git_buf refs_path = GIT_BUF_INIT;

	if (git_buf_joinpath(&refs_path, backend->path, GIT_REFS_DIR) < 0)
		return -1;

	/*
	 * Load all the loose files from disk into the Packfile table.
	 * This will overwrite any old packed entries with their
	 * updated loose versions
	 */
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	error = git_path_direach(
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		&refs_path, backend->direach_flags, _dirent_loose_load, backend);
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	git_buf_free(&refs_path);

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	return error;
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}

static int refdb_fs_backend__exists(
	int *exists,
	git_refdb_backend *_backend,
	const char *ref_name)
{
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	refdb_fs_backend *backend = (refdb_fs_backend *)_backend;
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	git_buf ref_path = GIT_BUF_INIT;

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	assert(backend);
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	if (packed_reload(backend) < 0 ||
		git_buf_joinpath(&ref_path, backend->path, ref_name) < 0)
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		return -1;

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	*exists = git_path_isfile(ref_path.ptr) ||
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		(git_sortedcache_lookup(backend->refcache, ref_name) != NULL);
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	git_buf_free(&ref_path);
	return 0;
}

static const char *loose_parse_symbolic(git_buf *file_content)
{
	const unsigned int header_len = (unsigned int)strlen(GIT_SYMREF);
	const char *refname_start;

	refname_start = (const char *)file_content->ptr;

	if (git_buf_len(file_content) < header_len + 1) {
		giterr_set(GITERR_REFERENCE, "Corrupted loose reference file");
		return NULL;
	}

	/*
	 * Assume we have already checked for the header
	 * before calling this function
	 */
	refname_start += header_len;

	return refname_start;
}

static int loose_lookup(
	git_reference **out,
	refdb_fs_backend *backend,
	const char *ref_name)
{
	git_buf ref_file = GIT_BUF_INIT;
	int error = 0;

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	if (out)
		*out = NULL;

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	if ((error = loose_readbuffer(&ref_file, backend->path, ref_name)) < 0)
		/* cannot read loose ref file - gah */;
	else if (git__prefixcmp(git_buf_cstr(&ref_file), GIT_SYMREF) == 0) {
		const char *target;
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		git_buf_rtrim(&ref_file);

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		if (!(target = loose_parse_symbolic(&ref_file)))
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			error = -1;
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		else if (out != NULL)
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			*out = git_reference__alloc_symbolic(ref_name, target);
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	} else {
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		git_oid oid;
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		if (!(error = loose_parse_oid(&oid, ref_name, &ref_file)) &&
			out != NULL)
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			*out = git_reference__alloc(ref_name, &oid, NULL);
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	}

	git_buf_free(&ref_file);
	return error;
}

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static int ref_error_notfound(const char *name)
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{
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	giterr_set(GITERR_REFERENCE, "Reference '%s' not found", name);
	return GIT_ENOTFOUND;
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}

static int packed_lookup(
	git_reference **out,
	refdb_fs_backend *backend,
	const char *ref_name)
{
	int error = 0;
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	struct packref *entry;
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	if (packed_reload(backend) < 0)
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		return -1;
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	if (git_sortedcache_rlock(backend->refcache) < 0)
		return -1;
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	entry = git_sortedcache_lookup(backend->refcache, ref_name);
	if (!entry) {
		error = ref_error_notfound(ref_name);
	} else {
		*out = git_reference__alloc(ref_name, &entry->oid, &entry->peel);
		if (!*out)
			error = -1;
	}

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	git_sortedcache_runlock(backend->refcache);

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	return error;
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}

static int refdb_fs_backend__lookup(
	git_reference **out,
	git_refdb_backend *_backend,
	const char *ref_name)
{
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	refdb_fs_backend *backend = (refdb_fs_backend *)_backend;
	int error;
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	assert(backend);
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	if (!(error = loose_lookup(out, backend, ref_name)))
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		return 0;

	/* only try to lookup this reference on the packfile if it
	 * wasn't found on the loose refs; not if there was a critical error */
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	if (error == GIT_ENOTFOUND) {
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		giterr_clear();
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		error = packed_lookup(out, backend, ref_name);
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	}

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	return error;
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}

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typedef struct {
	git_reference_iterator parent;
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	char *glob;
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	git_pool pool;
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	git_vector loose;
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	git_sortedcache *cache;
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	size_t loose_pos;
	size_t packed_pos;
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} refdb_fs_iter;

static void refdb_fs_backend__iterator_free(git_reference_iterator *_iter)
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{
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	refdb_fs_iter *iter = (refdb_fs_iter *) _iter;
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	git_vector_free(&iter->loose);
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	git_pool_clear(&iter->pool);
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	git_sortedcache_free(iter->cache);
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	git__free(iter);
}
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static int iter_load_loose_paths(refdb_fs_backend *backend, refdb_fs_iter *iter)
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{
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	int error = 0;
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	git_buf path = GIT_BUF_INIT;
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	git_iterator *fsit = NULL;
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	const git_index_entry *entry = NULL;
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	if (!backend->path) /* do nothing if no path for loose refs */
		return 0;

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	if ((error = git_buf_printf(&path, "%s/refs", backend->path)) < 0 ||
		(error = git_iterator_for_filesystem(
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			&fsit, path.ptr, backend->iterator_flags, NULL, NULL)) < 0) {
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		git_buf_free(&path);
		return error;
	}
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	error = git_buf_sets(&path, GIT_REFS_DIR);
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	while (!error && !git_iterator_advance(&entry, fsit)) {
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		const char *ref_name;
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		struct packref *ref;
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		char *ref_dup;
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		git_buf_truncate(&path, strlen(GIT_REFS_DIR));
		git_buf_puts(&path, entry->path);
		ref_name = git_buf_cstr(&path);
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		if (git__suffixcmp(ref_name, ".lock") == 0 ||
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			(iter->glob && p_fnmatch(iter->glob, ref_name, 0) != 0))
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			continue;
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		git_sortedcache_rlock(backend->refcache);
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		ref = git_sortedcache_lookup(backend->refcache, ref_name);
		if (ref)
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			ref->flags |= PACKREF_SHADOWED;
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		git_sortedcache_runlock(backend->refcache);
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		ref_dup = git_pool_strdup(&iter->pool, ref_name);
		if (!ref_dup)
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			error = -1;
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		else
			error = git_vector_insert(&iter->loose, ref_dup);
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	}
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	git_iterator_free(fsit);
	git_buf_free(&path);
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	return error;
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}

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static int refdb_fs_backend__iterator_next(
	git_reference **out, git_reference_iterator *_iter)
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{
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	int error = GIT_ITEROVER;
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	refdb_fs_iter *iter = (refdb_fs_iter *)_iter;
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	refdb_fs_backend *backend = (refdb_fs_backend *)iter->parent.db->backend;
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	struct packref *ref;
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	while (iter->loose_pos < iter->loose.length) {
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		const char *path = git_vector_get(&iter->loose, iter->loose_pos++);
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		if (loose_lookup(out, backend, path) == 0)
			return 0;

		giterr_clear();
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	}
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	if (!iter->cache) {
		if ((error = git_sortedcache_copy(&iter->cache, backend->refcache, 1, NULL, NULL)) < 0)
			return error;
	}
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	error = GIT_ITEROVER;
	while (iter->packed_pos < git_sortedcache_entrycount(iter->cache)) {
		ref = git_sortedcache_entry(iter->cache, iter->packed_pos++);
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		if (!ref) /* stop now if another thread deleted refs and we past end */
			break;
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		if (ref->flags & PACKREF_SHADOWED)
			continue;
		if (iter->glob && p_fnmatch(iter->glob, ref->name, 0) != 0)
			continue;
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		*out = git_reference__alloc(ref->name, &ref->oid, &ref->peel);
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		error = (*out != NULL) ? 0 : -1;
		break;
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	}

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	return error;
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}

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static int refdb_fs_backend__iterator_next_name(
	const char **out, git_reference_iterator *_iter)
{
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	int error = GIT_ITEROVER;
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	refdb_fs_iter *iter = (refdb_fs_iter *)_iter;
	refdb_fs_backend *backend = (refdb_fs_backend *)iter->parent.db->backend;
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	struct packref *ref;
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	while (iter->loose_pos < iter->loose.length) {
		const char *path = git_vector_get(&iter->loose, iter->loose_pos++);

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		if (loose_lookup(NULL, backend, path) == 0) {
			*out = path;
			return 0;
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		}

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		giterr_clear();
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	}

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	if (!iter->cache) {
		if ((error = git_sortedcache_copy(&iter->cache, backend->refcache, 1, NULL, NULL)) < 0)
			return error;
	}
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	error = GIT_ITEROVER;
	while (iter->packed_pos < git_sortedcache_entrycount(iter->cache)) {
		ref = git_sortedcache_entry(iter->cache, iter->packed_pos++);
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		if (!ref) /* stop now if another thread deleted refs and we past end */
			break;
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		if (ref->flags & PACKREF_SHADOWED)
			continue;
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		if (iter->glob && p_fnmatch(iter->glob, ref->name, 0) != 0)
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			continue;

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		*out = ref->name;
		error = 0;
		break;
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	}

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	return error;
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}

static int refdb_fs_backend__iterator(
	git_reference_iterator **out, git_refdb_backend *_backend, const char *glob)
{
	refdb_fs_iter *iter;
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	refdb_fs_backend *backend = (refdb_fs_backend *)_backend;
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	assert(backend);
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	if (packed_reload(backend) < 0)
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		return -1;

	iter = git__calloc(1, sizeof(refdb_fs_iter));
	GITERR_CHECK_ALLOC(iter);

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	if (git_pool_init(&iter->pool, 1, 0) < 0 ||
		git_vector_init(&iter->loose, 8, NULL) < 0)
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		goto fail;

	if (glob != NULL &&
		(iter->glob = git_pool_strdup(&iter->pool, glob)) == NULL)
		goto fail;
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	iter->parent.next = refdb_fs_backend__iterator_next;
	iter->parent.next_name = refdb_fs_backend__iterator_next_name;
	iter->parent.free = refdb_fs_backend__iterator_free;

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	if (iter_load_loose_paths(backend, iter) < 0)
		goto fail;
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	*out = (git_reference_iterator *)iter;
	return 0;
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fail:
	refdb_fs_backend__iterator_free((git_reference_iterator *)iter);
	return -1;
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}

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static bool ref_is_available(
	const char *old_ref, const char *new_ref, const char *this_ref)
{
	if (old_ref == NULL || strcmp(old_ref, this_ref)) {
		size_t reflen = strlen(this_ref);
		size_t newlen = strlen(new_ref);
		size_t cmplen = reflen < newlen ? reflen : newlen;
		const char *lead = reflen < newlen ? new_ref : this_ref;

		if (!strncmp(new_ref, this_ref, cmplen) && lead[cmplen] == '/') {
			return false;
		}
	}

	return true;
}

static int reference_path_available(
	refdb_fs_backend *backend,
	const char *new_ref,
	const char* old_ref,
	int force)
{
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	size_t i;
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	if (packed_reload(backend) < 0)
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		return -1;

	if (!force) {
		int exists;

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		if (refdb_fs_backend__exists(
				&exists, (git_refdb_backend *)backend, new_ref) < 0)
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			return -1;

		if (exists) {
			giterr_set(GITERR_REFERENCE,
				"Failed to write reference '%s': a reference with "
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				"that name already exists.", new_ref);
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			return GIT_EEXISTS;
		}
	}

691
	git_sortedcache_rlock(backend->refcache);
692 693

	for (i = 0; i < git_sortedcache_entrycount(backend->refcache); ++i) {
694
		struct packref *ref = git_sortedcache_entry(backend->refcache, i);
695

696 697
		if (ref && !ref_is_available(old_ref, new_ref, ref->name)) {
			git_sortedcache_runlock(backend->refcache);
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698
			giterr_set(GITERR_REFERENCE,
699
				"Path to reference '%s' collides with existing one", new_ref);
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700 701
			return -1;
		}
702
	}
703

704
	git_sortedcache_runlock(backend->refcache);
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705 706
	return 0;
}
707

708
static int loose_lock(git_filebuf *file, refdb_fs_backend *backend, const char *name)
709
{
710
	int error;
711 712
	git_buf ref_path = GIT_BUF_INIT;

713
	assert(file && backend && name);
714

715 716 717 718 719
	if (!git_path_isvalid(backend->repo, name, GIT_PATH_REJECT_DEFAULTS)) {
		giterr_set(GITERR_INVALID, "Invalid reference name '%s'.", name);
		return GIT_EINVALIDSPEC;
	}

720 721 722
	/* Remove a possibly existing empty directory hierarchy
	 * which name would collide with the reference name
	 */
723
	if (git_futils_rmdir_r(name, backend->path, GIT_RMDIR_SKIP_NONEMPTY) < 0)
724 725
		return -1;

726
	if (git_buf_joinpath(&ref_path, backend->path, name) < 0)
727 728
		return -1;

729
	error = git_filebuf_open(file, ref_path.ptr, GIT_FILEBUF_FORCE, GIT_REFS_FILE_MODE);
730 731

	git_buf_free(&ref_path);
732
        return error;
733
}
734

735 736
static int loose_commit(git_filebuf *file, const git_reference *ref)
{
737 738
	assert(file && ref);

739 740
	if (ref->type == GIT_REF_OID) {
		char oid[GIT_OID_HEXSZ + 1];
741
		git_oid_nfmt(oid, sizeof(oid), &ref->target.oid);
742

743
		git_filebuf_printf(file, "%s\n", oid);
744
	} else if (ref->type == GIT_REF_SYMBOLIC) {
745
		git_filebuf_printf(file, GIT_SYMREF "%s\n", ref->target.symbolic);
746 747 748 749
	} else {
		assert(0); /* don't let this happen */
	}

750
	return git_filebuf_commit(file);
751 752
}

753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803
static int refdb_fs_backend__lock(void **out, git_refdb_backend *_backend, const char *refname)
{
	int error;
	git_filebuf *lock;
	refdb_fs_backend *backend = (refdb_fs_backend *) _backend;

	lock = git__calloc(1, sizeof(git_filebuf));
	GITERR_CHECK_ALLOC(lock);

	if ((error = loose_lock(lock, backend, refname)) < 0) {
		git__free(lock);
		return error;
	}

	*out = lock;
	return 0;
}

static int refdb_fs_backend__write_tail(
	git_refdb_backend *_backend,
	const git_reference *ref,
	git_filebuf *file,
	int update_reflog,
	const git_signature *who,
	const char *message,
	const git_oid *old_id,
	const char *old_target);

static int refdb_fs_backend__delete_tail(
	git_refdb_backend *_backend,
	git_filebuf *file,
	const char *ref_name,
	const git_oid *old_id, const char *old_target);

static int refdb_fs_backend__unlock(git_refdb_backend *backend, void *payload, int success, int update_reflog,
				    const git_reference *ref, const git_signature *sig, const char *message)
{
	git_filebuf *lock = (git_filebuf *) payload;
	int error = 0;

	if (success == 2)
		error = refdb_fs_backend__delete_tail(backend, lock, ref->name, NULL, NULL);
	else if (success)
		error = refdb_fs_backend__write_tail(backend, ref, lock, update_reflog, sig, message, NULL, NULL);
	else
		git_filebuf_cleanup(lock);

	git__free(lock);
	return error;
}

804 805 806 807 808 809 810 811 812 813 814 815
/*
 * Find out what object this reference resolves to.
 *
 * For references that point to a 'big' tag (e.g. an
 * actual tag object on the repository), we need to
 * cache on the packfile the OID of the object to
 * which that 'big tag' is pointing to.
 */
static int packed_find_peel(refdb_fs_backend *backend, struct packref *ref)
{
	git_object *object;

816
	if (ref->flags & PACKREF_HAS_PEEL || ref->flags & PACKREF_CANNOT_PEEL)
817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836
		return 0;

	/*
	 * Find the tagged object in the repository
	 */
	if (git_object_lookup(&object, backend->repo, &ref->oid, GIT_OBJ_ANY) < 0)
		return -1;

	/*
	 * If the tagged object is a Tag object, we need to resolve it;
	 * if the ref is actually a 'weak' ref, we don't need to resolve
	 * anything.
	 */
	if (git_object_type(object) == GIT_OBJ_TAG) {
		git_tag *tag = (git_tag *)object;

		/*
		 * Find the object pointed at by this tag
		 */
		git_oid_cpy(&ref->peel, git_tag_target_id(tag));
837
		ref->flags |= PACKREF_HAS_PEEL;
838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855

		/*
		 * The reference has now cached the resolved OID, and is
		 * marked at such. When written to the packfile, it'll be
		 * accompanied by this resolved oid
		 */
	}

	git_object_free(object);
	return 0;
}

/*
 * Write a single reference into a packfile
 */
static int packed_write_ref(struct packref *ref, git_filebuf *file)
{
	char oid[GIT_OID_HEXSZ + 1];
856
	git_oid_nfmt(oid, sizeof(oid), &ref->oid);
857 858 859 860 861 862 863 864 865 866 867

	/*
	 * For references that peel to an object in the repo, we must
	 * write the resulting peel on a separate line, e.g.
	 *
	 *	6fa8a902cc1d18527e1355773c86721945475d37 refs/tags/libgit2-0.4
	 *	^2ec0cb7959b0bf965d54f95453f5b4b34e8d3100
	 *
	 * This obviously only applies to tags.
	 * The required peels have already been loaded into `ref->peel_target`.
	 */
868
	if (ref->flags & PACKREF_HAS_PEEL) {
869
		char peel[GIT_OID_HEXSZ + 1];
870
		git_oid_nfmt(peel, sizeof(peel), &ref->peel);
871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892

		if (git_filebuf_printf(file, "%s %s\n^%s\n", oid, ref->name, peel) < 0)
			return -1;
	} else {
		if (git_filebuf_printf(file, "%s %s\n", oid, ref->name) < 0)
			return -1;
	}

	return 0;
}

/*
 * Remove all loose references
 *
 * Once we have successfully written a packfile,
 * all the loose references that were packed must be
 * removed from disk.
 *
 * This is a dangerous method; make sure the packfile
 * is well-written, because we are destructing references
 * here otherwise.
 */
893
static int packed_remove_loose(refdb_fs_backend *backend)
894
{
895
	size_t i;
896 897 898
	git_buf full_path = GIT_BUF_INIT;
	int failed = 0;

899 900 901 902
	/* backend->refcache is already locked when this is called */

	for (i = 0; i < git_sortedcache_entrycount(backend->refcache); ++i) {
		struct packref *ref = git_sortedcache_entry(backend->refcache, i);
903

904
		if (!ref || !(ref->flags & PACKREF_WAS_LOOSE))
905 906 907 908 909
			continue;

		if (git_buf_joinpath(&full_path, backend->path, ref->name) < 0)
			return -1; /* critical; do not try to recover on oom */

910
		if (git_path_exists(full_path.ptr) && p_unlink(full_path.ptr) < 0) {
911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936
			if (failed)
				continue;

			giterr_set(GITERR_REFERENCE,
				"Failed to remove loose reference '%s' after packing: %s",
				full_path.ptr, strerror(errno));
			failed = 1;
		}

		/*
		 * if we fail to remove a single file, this is *not* good,
		 * but we should keep going and remove as many as possible.
		 * After we've removed as many files as possible, we return
		 * the error code anyway.
		 */
	}

	git_buf_free(&full_path);
	return failed ? -1 : 0;
}

/*
 * Write all the contents in the in-memory packfile to disk.
 */
static int packed_write(refdb_fs_backend *backend)
{
937
	git_sortedcache *refcache = backend->refcache;
938
	git_filebuf pack_file = GIT_FILEBUF_INIT;
939
	size_t i;
940

941
	/* lock the cache to updates while we do this */
942
	if (git_sortedcache_wlock(refcache) < 0)
943 944
		return -1;

945
	/* Open the file! */
946
	if (git_filebuf_open(&pack_file, git_sortedcache_path(refcache), 0, GIT_PACKEDREFS_FILE_MODE) < 0)
947
		goto fail;
948 949 950 951 952

	/* Packfiles have a header... apparently
	 * This is in fact not required, but we might as well print it
	 * just for kicks */
	if (git_filebuf_printf(&pack_file, "%s\n", GIT_PACKEDREFS_HEADER) < 0)
953
		goto fail;
954

955 956
	for (i = 0; i < git_sortedcache_entrycount(refcache); ++i) {
		struct packref *ref = git_sortedcache_entry(refcache, i);
957 958

		if (packed_find_peel(backend, ref) < 0)
959
			goto fail;
960 961

		if (packed_write_ref(ref, &pack_file) < 0)
962
			goto fail;
963 964 965 966
	}

	/* if we've written all the references properly, we can commit
	 * the packfile to make the changes effective */
967
	if (git_filebuf_commit(&pack_file) < 0)
968
		goto fail;
969 970 971

	/* when and only when the packfile has been properly written,
	 * we can go ahead and remove the loose refs */
972
	if (packed_remove_loose(backend) < 0)
973
		goto fail;
974

975 976
	git_sortedcache_updated(refcache);
	git_sortedcache_wunlock(refcache);
977 978 979 980

	/* we're good now */
	return 0;

981
fail:
982
	git_filebuf_cleanup(&pack_file);
983
	git_sortedcache_wunlock(refcache);
984 985 986 987

	return -1;
}

988
static int reflog_append(refdb_fs_backend *backend, const git_reference *ref, const git_oid *old, const git_oid *new, const git_signature *author, const char *message);
989 990 991
static int has_reflog(git_repository *repo, const char *name);

/* We only write if it's under heads/, remotes/ or notes/ or if it already has a log */
992
static int should_write_reflog(int *write, git_repository *repo, const char *name)
993
{
994
	int error, logall;
995

996 997
	error = git_repository__cvar(&logall, repo, GIT_CVAR_LOGALLREFUPDATES);
	if (error < 0)
998 999
		return error;

1000 1001 1002
	/* Defaults to the opposite of the repo being bare */
	if (logall == GIT_LOGALLREFUPDATES_UNSET)
		logall = !git_repository_is_bare(repo);
1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015

	if (!logall) {
		*write = 0;
	} else if (has_reflog(repo, name)) {
		*write = 1;
	} else if (!git__prefixcmp(name, GIT_REFS_HEADS_DIR) ||
		   !git__strcmp(name, GIT_HEAD_FILE) ||
		   !git__prefixcmp(name, GIT_REFS_REMOTES_DIR) ||
		   !git__prefixcmp(name, GIT_REFS_NOTES_DIR)) {
		*write = 1;
	} else {
		*write = 0;
	}
1016 1017 1018

	return 0;
}
1019

1020
static int cmp_old_ref(int *cmp, git_refdb_backend *backend, const char *name,
1021 1022 1023 1024 1025 1026
	const git_oid *old_id, const char *old_target)
{
	int error = 0;
	git_reference *old_ref = NULL;

	*cmp = 0;
1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041
	/* It "matches" if there is no old value to compare against */
	if (!old_id && !old_target)
		return 0;

	if ((error = refdb_fs_backend__lookup(&old_ref, backend, name)) < 0)
		goto out;

	/* If the types don't match, there's no way the values do */
	if (old_id && old_ref->type != GIT_REF_OID) {
		*cmp = -1;
		goto out;
	}
	if (old_target && old_ref->type != GIT_REF_SYMBOLIC) {
		*cmp = 1;
		goto out;
1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055
	}

	if (old_id && old_ref->type == GIT_REF_OID)
		*cmp = git_oid_cmp(old_id, &old_ref->target.oid);

	if (old_target && old_ref->type == GIT_REF_SYMBOLIC)
		*cmp = git__strcmp(old_target, old_ref->target.symbolic);

out:
	git_reference_free(old_ref);

	return error;
}

1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072
/*
 * The git.git comment regarding this, for your viewing pleasure:
 *
 * Special hack: If a branch is updated directly and HEAD
 * points to it (may happen on the remote side of a push
 * for example) then logically the HEAD reflog should be
 * updated too.
 * A generic solution implies reverse symref information,
 * but finding all symrefs pointing to the given branch
 * would be rather costly for this rare event (the direct
 * update of a branch) to be worth it.  So let's cheat and
 * check with HEAD only which should cover 99% of all usage
 * scenarios (even 100% of the default ones).
 */
static int maybe_append_head(refdb_fs_backend *backend, const git_reference *ref, const git_signature *who, const char *message)
{
	int error;
1073
	git_oid old_id = {{0}};
1074 1075 1076 1077 1078
	git_reference *tmp = NULL, *head = NULL, *peeled = NULL;
	const char *name;

	if (ref->type == GIT_REF_SYMBOLIC)
		return 0;
1079

1080 1081
	/* if we can't resolve, we use {0}*40 as old id */
	git_reference_name_to_id(&old_id, backend->repo, ref->name);
1082

1083
	if ((error = git_reference_lookup(&head, backend->repo, GIT_HEAD_FILE)) < 0)
1084 1085
		return error;

1086 1087 1088
	if (git_reference_type(head) == GIT_REF_OID)
		goto cleanup;

1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111
	if ((error = git_reference_lookup(&tmp, backend->repo, GIT_HEAD_FILE)) < 0)
		goto cleanup;

	/* Go down the symref chain until we find the branch */
	while (git_reference_type(tmp) == GIT_REF_SYMBOLIC) {
		error = git_reference_lookup(&peeled, backend->repo, git_reference_symbolic_target(tmp));
		if (error < 0)
			break;

		git_reference_free(tmp);
		tmp = peeled;
	}

	if (error == GIT_ENOTFOUND) {
		error = 0;
		name = git_reference_symbolic_target(tmp);
	} else if (error < 0) {
		goto cleanup;
	} else {
		name = git_reference_name(tmp);
	}

	if (strcmp(name, ref->name))
1112 1113
		goto cleanup;

1114 1115
	error = reflog_append(backend, head, &old_id, git_reference_target(ref), who, message);

1116
cleanup:
1117
	git_reference_free(tmp);
1118 1119 1120 1121
	git_reference_free(head);
	return error;
}

1122 1123
static int refdb_fs_backend__write(
	git_refdb_backend *_backend,
Vicent Marti committed
1124
	const git_reference *ref,
1125
	int force,
1126
	const git_signature *who,
1127
	const char *message,
1128 1129
	const git_oid *old_id,
	const char *old_target)
1130
{
1131
	refdb_fs_backend *backend = (refdb_fs_backend *)_backend;
1132
	git_filebuf file = GIT_FILEBUF_INIT;
1133
	int error = 0;
1134

1135
	assert(backend);
1136

Vicent Marti committed
1137 1138 1139 1140
	error = reference_path_available(backend, ref->name, NULL, force);
	if (error < 0)
		return error;

1141
	/* We need to perform the reflog append and old value check under the ref's lock */
1142
	if ((error = loose_lock(&file, backend, ref->name)) < 0)
1143 1144
		return error;

1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162
	return refdb_fs_backend__write_tail(_backend, ref, &file, true, who, message, old_id, old_target);
}

static int refdb_fs_backend__write_tail(
	git_refdb_backend *_backend,
	const git_reference *ref,
	git_filebuf *file,
	int update_reflog,
	const git_signature *who,
	const char *message,
	const git_oid *old_id,
	const char *old_target)
{
	refdb_fs_backend *backend = (refdb_fs_backend *)_backend;
	int error = 0, cmp = 0, should_write;
	const char *new_target = NULL;
	const git_oid *new_id = NULL;

1163
	if ((error = cmp_old_ref(&cmp, _backend, ref->name, old_id, old_target)) < 0)
1164
		goto on_error;
1165 1166 1167 1168 1169

	if (cmp) {
		giterr_set(GITERR_REFERENCE, "old reference value does not match");
		error = GIT_EMODIFIED;
		goto on_error;
1170 1171
	}

1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186
	if (ref->type == GIT_REF_SYMBOLIC)
		new_target = ref->target.symbolic;
	else
		new_id = &ref->target.oid;

	error = cmp_old_ref(&cmp, _backend, ref->name, new_id, new_target);
	if (error < 0 && error != GIT_ENOTFOUND)
		goto on_error;

	/* Don't update if we have the same value */
	if (!error && !cmp) {
		error = 0;
		goto on_error; /* not really error */
	}

1187 1188
	if (update_reflog) {
		if ((error = should_write_reflog(&should_write, backend->repo, ref->name)) < 0)
1189
			goto on_error;
1190 1191 1192 1193 1194 1195 1196

		if (should_write) {
			if ((error = reflog_append(backend, ref, NULL, NULL, who, message)) < 0)
				goto on_error;
			if ((error = maybe_append_head(backend, ref, who, message)) < 0)
				goto on_error;
		}
1197 1198
	}

1199
	return loose_commit(file, ref);
1200 1201

on_error:
1202
        git_filebuf_cleanup(file);
1203
        return error;
1204 1205 1206 1207
}

static int refdb_fs_backend__delete(
	git_refdb_backend *_backend,
1208 1209
	const char *ref_name,
	const git_oid *old_id, const char *old_target)
1210
{
1211
	refdb_fs_backend *backend = (refdb_fs_backend *)_backend;
1212
	git_filebuf file = GIT_FILEBUF_INIT;
1213
	int error = 0;
1214

1215
	assert(backend && ref_name);
1216

1217 1218 1219
	if ((error = loose_lock(&file, backend, ref_name)) < 0)
		return error;

1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234
	return refdb_fs_backend__delete_tail(_backend, &file, ref_name, old_id, old_target);
}

static int refdb_fs_backend__delete_tail(
	git_refdb_backend *_backend,
	git_filebuf *file,
	const char *ref_name,
	const git_oid *old_id, const char *old_target)
{
	refdb_fs_backend *backend = (refdb_fs_backend *)_backend;
	git_buf loose_path = GIT_BUF_INIT;
	size_t pack_pos;
	int error = 0, cmp = 0;
	bool loose_deleted = 0;

1235 1236 1237 1238 1239 1240 1241 1242 1243 1244
	error = cmp_old_ref(&cmp, _backend, ref_name, old_id, old_target);
	if (error < 0)
		goto cleanup;

	if (cmp) {
		giterr_set(GITERR_REFERENCE, "old reference value does not match");
		error = GIT_EMODIFIED;
		goto cleanup;
	}

1245
	/* If a loose reference exists, remove it from the filesystem */
Vicent Marti committed
1246
	if (git_buf_joinpath(&loose_path, backend->path, ref_name) < 0)
1247 1248 1249 1250 1251 1252
		return -1;

	if (git_path_isfile(loose_path.ptr)) {
		error = p_unlink(loose_path.ptr);
		loose_deleted = 1;
	}
1253

1254 1255 1256
	git_buf_free(&loose_path);

	if (error != 0)
1257
		goto cleanup;
1258

1259 1260
	if ((error = packed_reload(backend)) < 0)
		goto cleanup;
1261

1262
	/* If a packed reference exists, remove it from the packfile and repack */
1263 1264
	if ((error = git_sortedcache_wlock(backend->refcache)) < 0)
		goto cleanup;
Vicent Marti committed
1265

1266 1267
	if (!(error = git_sortedcache_lookup_index(
			&pack_pos, backend->refcache, ref_name)))
1268
		error = git_sortedcache_remove(backend->refcache, pack_pos);
1269

1270
	git_sortedcache_wunlock(backend->refcache);
1271

1272 1273 1274 1275 1276 1277
	if (error == GIT_ENOTFOUND) {
		error = loose_deleted ? 0 : ref_error_notfound(ref_name);
		goto cleanup;
	}

	error = packed_write(backend);
1278

1279
cleanup:
1280
	git_filebuf_cleanup(file);
1281 1282

	return error;
1283 1284
}

1285 1286
static int refdb_reflog_fs__rename(git_refdb_backend *_backend, const char *old_name, const char *new_name);

Vicent Marti committed
1287 1288 1289 1290 1291
static int refdb_fs_backend__rename(
	git_reference **out,
	git_refdb_backend *_backend,
	const char *old_name,
	const char *new_name,
1292
	int force,
1293
	const git_signature *who,
1294
	const char *message)
Vicent Marti committed
1295
{
1296
	refdb_fs_backend *backend = (refdb_fs_backend *)_backend;
Vicent Marti committed
1297
	git_reference *old, *new;
1298
	git_filebuf file = GIT_FILEBUF_INIT;
Vicent Marti committed
1299 1300
	int error;

1301
	assert(backend);
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1302

1303 1304 1305
	if ((error = reference_path_available(
			backend, new_name, old_name, force)) < 0 ||
		(error = refdb_fs_backend__lookup(&old, _backend, old_name)) < 0)
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		return error;

1308
	if ((error = refdb_fs_backend__delete(_backend, old_name, NULL, NULL)) < 0) {
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		git_reference_free(old);
		return error;
	}

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	new = git_reference__set_name(old, new_name);
	if (!new) {
		git_reference_free(old);
		return -1;
Vicent Marti committed
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	}

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	if ((error = loose_lock(&file, backend, new->name)) < 0) {
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		git_reference_free(new);
		return error;
	}

	/* Try to rename the refog; it's ok if the old doesn't exist */
	error = refdb_reflog_fs__rename(_backend, old_name, new_name);
	if (((error == 0) || (error == GIT_ENOTFOUND)) &&
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	    ((error = reflog_append(backend, new, git_reference_target(new), NULL, who, message)) < 0)) {
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		git_reference_free(new);
		git_filebuf_cleanup(&file);
		return error;
	}

	if (error < 0) {
		git_reference_free(new);
		git_filebuf_cleanup(&file);
		return error;
	}


	if ((error = loose_commit(&file, new)) < 0 || out == NULL) {
Vicent Marti committed
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		git_reference_free(new);
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		return error;
Vicent Marti committed
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	}

1345
	*out = new;
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	return 0;
}

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static int refdb_fs_backend__compress(git_refdb_backend *_backend)
{
1351
	refdb_fs_backend *backend = (refdb_fs_backend *)_backend;
1352

1353
	assert(backend);
1354

1355
	if (packed_reload(backend) < 0 || /* load the existing packfile */
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		packed_loadloose(backend) < 0 || /* add all the loose refs */
		packed_write(backend) < 0) /* write back to disk */
		return -1;

	return 0;
}

static void refdb_fs_backend__free(git_refdb_backend *_backend)
{
1365
	refdb_fs_backend *backend = (refdb_fs_backend *)_backend;
1366

1367
	assert(backend);
1368

1369
	git_sortedcache_free(backend->refcache);
Vicent Marti committed
1370
	git__free(backend->path);
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	git__free(backend);
}

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static int setup_namespace(git_buf *path, git_repository *repo)
{
nulltoken committed
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	char *parts, *start, *end;
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	/* Not all repositories have a path */
	if (repo->path_repository == NULL)
		return 0;

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	/* Load the path to the repo first */
	git_buf_puts(path, repo->path_repository);

	/* if the repo is not namespaced, nothing else to do */
	if (repo->namespace == NULL)
		return 0;

	parts = end = git__strdup(repo->namespace);
	if (parts == NULL)
		return -1;

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	/*
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	 * From `man gitnamespaces`:
	 *  namespaces which include a / will expand to a hierarchy
	 *  of namespaces; for example, GIT_NAMESPACE=foo/bar will store
	 *  refs under refs/namespaces/foo/refs/namespaces/bar/
	 */
	while ((start = git__strsep(&end, "/")) != NULL) {
		git_buf_printf(path, "refs/namespaces/%s/", start);
	}

	git_buf_printf(path, "refs/namespaces/%s/refs", end);
Vicent Marti committed
1404
	git__free(parts);
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	/* Make sure that the folder with the namespace exists */
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	if (git_futils_mkdir_r(git_buf_cstr(path), repo->path_repository, 0777) < 0)
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		return -1;

1410
	/* Return root of the namespaced path, i.e. without the trailing '/refs' */
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	git_buf_rtruncate_at_char(path, '/');
	return 0;
}

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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,
1515
			O_WRONLY | O_CREAT,
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			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)
{
1524
	return git_buf_join3(path, '/', repo->path_repository, GIT_REFLOG_DIR, name);
1525 1526
}

1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541
static int refdb_reflog_fs__ensure_log(git_refdb_backend *_backend, const char *name)
{
	refdb_fs_backend *backend;
	git_repository *repo;
	git_buf path = GIT_BUF_INIT;
	int error;

	assert(_backend && name);

	backend = (refdb_fs_backend *) _backend;
	repo = backend->repo;

	if ((error = retrieve_reflog_path(&path, repo, name)) < 0)
		return error;

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	error = create_new_reflog_file(git_buf_cstr(&path));
	git_buf_free(&path);

	return error;
1546 1547
}

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static int has_reflog(git_repository *repo, const char *name)
{
	int ret = 0;
	git_buf path = GIT_BUF_INIT;

	if (retrieve_reflog_path(&path, repo, name) < 0)
		goto cleanup;

	ret = git_path_isfile(git_buf_cstr(&path));

cleanup:
	git_buf_free(&path);
	return ret;
}

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static int refdb_reflog_fs__has_log(git_refdb_backend *_backend, const char *name)
{
	refdb_fs_backend *backend;

	assert(_backend && name);

	backend = (refdb_fs_backend *) _backend;

	return has_reflog(backend->repo, name);
}

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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);
}

1653 1654 1655 1656 1657 1658 1659 1660
static int lock_reflog(git_filebuf *file, refdb_fs_backend *backend, const char *refname)
{
	git_repository *repo;
	git_buf log_path = GIT_BUF_INIT;
	int error;

	repo = backend->repo;

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	if (!git_path_isvalid(backend->repo, refname, GIT_PATH_REJECT_DEFAULTS)) {
		giterr_set(GITERR_INVALID, "Invalid reference name '%s'.", refname);
		return GIT_EINVALIDSPEC;
	}

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	if (retrieve_reflog_path(&log_path, repo, refname) < 0)
		return -1;

	if (!git_path_isfile(git_buf_cstr(&log_path))) {
		giterr_set(GITERR_INVALID,
			"Log file for reference '%s' doesn't exist.", refname);
		error = -1;
		goto cleanup;
	}

	error = git_filebuf_open(file, git_buf_cstr(&log_path), 0, GIT_REFLOG_FILE_MODE);

cleanup:
	git_buf_free(&log_path);

	return error;
}

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static int refdb_reflog_fs__write(git_refdb_backend *_backend, git_reflog *reflog)
{
	int error = -1;
	unsigned int i;
	git_reflog_entry *entry;
	refdb_fs_backend *backend;
	git_buf log = GIT_BUF_INIT;
	git_filebuf fbuf = GIT_FILEBUF_INIT;

	assert(_backend && reflog);

	backend = (refdb_fs_backend *) _backend;

1697
	if ((error = lock_reflog(&fbuf, backend, reflog->ref_name)) < 0)
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		return -1;

	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;
	}

1708
	error = git_filebuf_commit(&fbuf);
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	goto success;

cleanup:
	git_filebuf_cleanup(&fbuf);

success:
	git_buf_free(&log);
1716

1717 1718 1719
	return error;
}

1720
/* Append to the reflog, must be called under reference lock */
1721
static int reflog_append(refdb_fs_backend *backend, const git_reference *ref, const git_oid *old, const git_oid *new, const git_signature *who, const char *message)
1722
{
1723
	int error, is_symbolic;
1724
	git_oid old_id = {{0}}, new_id = {{0}};
1725 1726 1727
	git_buf buf = GIT_BUF_INIT, path = GIT_BUF_INIT;
	git_repository *repo = backend->repo;

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	is_symbolic = ref->type == GIT_REF_SYMBOLIC;

	/* "normal" symbolic updates do not write */
	if (is_symbolic &&
	    strcmp(ref->name, GIT_HEAD_FILE) &&
	    !(old && new))
1734 1735
		return 0;

1736 1737 1738 1739
	/* From here on is_symoblic also means that it's HEAD */

	if (old) {
		git_oid_cpy(&old_id, old);
1740
	} else {
1741
		error = git_reference_name_to_id(&old_id, repo, ref->name);
1742
		if (error < 0 && error != GIT_ENOTFOUND)
1743 1744 1745
			return error;
	}

1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757
	if (new) {
		git_oid_cpy(&new_id, new);
	} else {
		if (!is_symbolic) {
			git_oid_cpy(&new_id, git_reference_target(ref));
		} else {
			error = git_reference_name_to_id(&new_id, repo, git_reference_symbolic_target(ref));
			if (error < 0 && error != GIT_ENOTFOUND)
				return error;
			/* detaching HEAD does not create an entry */
			if (error == GIT_ENOTFOUND)
				return 0;
1758

1759 1760
			giterr_clear();
		}
1761
	}
1762

1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773
	if ((error = serialize_reflog_entry(&buf, &old_id, &new_id, who, message)) < 0)
		goto cleanup;

	if ((error = retrieve_reflog_path(&path, repo, ref->name)) < 0)
		goto cleanup;

	if (((error = git_futils_mkpath2file(git_buf_cstr(&path), 0777)) < 0) &&
	    (error != GIT_EEXISTS)) {
		goto cleanup;
	}

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	/* If the new branch matches part of the namespace of a previously deleted branch,
	 * there maybe an obsolete/unused directory (or directory hierarchy) in the way.
	 */
	if (git_path_isdir(git_buf_cstr(&path)) &&
		(git_futils_rmdir_r(git_buf_cstr(&path), NULL, GIT_RMDIR_SKIP_NONEMPTY) < 0)) {
		error = -1;
		goto cleanup;
	}

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	error = git_futils_writebuffer(&buf, git_buf_cstr(&path), O_WRONLY|O_CREAT|O_APPEND, GIT_REFLOG_FILE_MODE);

cleanup:
	git_buf_free(&buf);
	git_buf_free(&path);

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	return error;
}

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;

1820 1821 1822 1823 1824
	if (!git_path_exists(git_buf_cstr(&old_path))) {
		error = GIT_ENOTFOUND;
		goto cleanup;
	}

1825 1826 1827 1828 1829 1830 1831 1832 1833 1834
	/*
	 * 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;

1835
	if ((fd = git_futils_mktmp(&temp_path, git_buf_cstr(&temp_path), GIT_REFLOG_FILE_MODE)) < 0) {
1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896
		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__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;

}

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int git_refdb_backend_fs(
	git_refdb_backend **backend_out,
1899
	git_repository *repository)
1900
{
1901
	int t = 0;
Vicent Marti committed
1902
	git_buf path = GIT_BUF_INIT;
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	refdb_fs_backend *backend;

	backend = git__calloc(1, sizeof(refdb_fs_backend));
	GITERR_CHECK_ALLOC(backend);

	backend->repo = repository;
Vicent Marti committed
1909

1910 1911
	if (setup_namespace(&path, repository) < 0)
		goto fail;
Vicent Marti committed
1912 1913

	backend->path = git_buf_detach(&path);
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	if (git_buf_joinpath(&path, backend->path, GIT_PACKEDREFS_FILE) < 0 ||
		git_sortedcache_new(
			&backend->refcache, offsetof(struct packref, name),
			NULL, NULL, packref_cmp, git_buf_cstr(&path)) < 0)
		goto fail;

	git_buf_free(&path);

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	if (!git_repository__cvar(&t, backend->repo, GIT_CVAR_IGNORECASE) && t) {
		backend->iterator_flags |= GIT_ITERATOR_IGNORE_CASE;
		backend->direach_flags  |= GIT_PATH_DIR_IGNORE_CASE;
	}
	if (!git_repository__cvar(&t, backend->repo, GIT_CVAR_PRECOMPOSE) && t) {
		backend->iterator_flags |= GIT_ITERATOR_PRECOMPOSE_UNICODE;
		backend->direach_flags  |= GIT_PATH_DIR_PRECOMPOSE_UNICODE;
	}

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	backend->parent.exists = &refdb_fs_backend__exists;
	backend->parent.lookup = &refdb_fs_backend__lookup;
1934
	backend->parent.iterator = &refdb_fs_backend__iterator;
1935
	backend->parent.write = &refdb_fs_backend__write;
1936
	backend->parent.del = &refdb_fs_backend__delete;
Vicent Marti committed
1937
	backend->parent.rename = &refdb_fs_backend__rename;
1938
	backend->parent.compress = &refdb_fs_backend__compress;
1939 1940
	backend->parent.lock = &refdb_fs_backend__lock;
	backend->parent.unlock = &refdb_fs_backend__unlock;
1941
	backend->parent.has_log = &refdb_reflog_fs__has_log;
1942
	backend->parent.ensure_log = &refdb_reflog_fs__ensure_log;
1943
	backend->parent.free = &refdb_fs_backend__free;
1944 1945 1946 1947
	backend->parent.reflog_read = &refdb_reflog_fs__read;
	backend->parent.reflog_write = &refdb_reflog_fs__write;
	backend->parent.reflog_rename = &refdb_reflog_fs__rename;
	backend->parent.reflog_delete = &refdb_reflog_fs__delete;
1948 1949 1950

	*backend_out = (git_refdb_backend *)backend;
	return 0;
1951 1952 1953 1954 1955 1956

fail:
	git_buf_free(&path);
	git__free(backend->path);
	git__free(backend);
	return -1;
1957
}