1 files changed, 198 insertions, 218 deletions

diff --git a/sha1_file.c b/sha1_file.c
index 06c809a..c08c0cb 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -36,9 +36,6 @@ static inline uintmax_t sz_fmt(size_t s) { return s; }
 
 const unsigned char null_sha1[20];
 
-static const char *no_log_pack_access = "no_log_pack_access";
-static const char *log_pack_access;
-
 /*
  * This is meant to hold a *small* number of objects that you would
  * want read_sha1_file() to be able to return, but yet you do not want
@@ -60,6 +57,12 @@ static struct cached_object empty_tree = {
 	0
 };
 
+/*
+ * A pointer to the last packed_git in which an object was found.
+ * When an object is sought, we look in this packfile first, because
+ * objects that are looked up at similar times are often in the same
+ * packfile as one another.
+ */
 static struct packed_git *last_found_pack;
 
 static struct cached_object *find_cached_object(const unsigned char *sha1)
@@ -105,50 +108,63 @@ int mkdir_in_gitdir(const char *path)
 	return adjust_shared_perm(path);
 }
 
-int safe_create_leading_directories(char *path)
+enum scld_error safe_create_leading_directories(char *path)
 {
-	char *pos = path + offset_1st_component(path);
-	struct stat st;
+	char *next_component = path + offset_1st_component(path);
+	enum scld_error ret = SCLD_OK;
+
+	while (ret == SCLD_OK && next_component) {
+		struct stat st;
+		char *slash = next_component, slash_character;
+
+		while (*slash && !is_dir_sep(*slash))
+			slash++;
 
-	while (pos) {
-		pos = strchr(pos, '/');
-		if (!pos)
+		if (!*slash)
 			break;
-		while (*++pos == '/')
-			;
-		if (!*pos)
+
+		next_component = slash + 1;
+		while (is_dir_sep(*next_component))
+			next_component++;
+		if (!*next_component)
 			break;
-		*--pos = '\0';
+
+		slash_character = *slash;
+		*slash = '\0';
 		if (!stat(path, &st)) {
 			/* path exists */
-			if (!S_ISDIR(st.st_mode)) {
-				*pos = '/';
-				return -3;
-			}
-		}
-		else if (mkdir(path, 0777)) {
+			if (!S_ISDIR(st.st_mode))
+				ret = SCLD_EXISTS;
+		} else if (mkdir(path, 0777)) {
 			if (errno == EEXIST &&
-			    !stat(path, &st) && S_ISDIR(st.st_mode)) {
+			    !stat(path, &st) && S_ISDIR(st.st_mode))
 				; /* somebody created it since we checked */
-			} else {
-				*pos = '/';
-				return -1;
-			}
-		}
-		else if (adjust_shared_perm(path)) {
-			*pos = '/';
-			return -2;
+			else if (errno == ENOENT)
+				/*
+				 * Either mkdir() failed because
+				 * somebody just pruned the containing
+				 * directory, or stat() failed because
+				 * the file that was in our way was
+				 * just removed.  Either way, inform
+				 * the caller that it might be worth
+				 * trying again:
+				 */
+				ret = SCLD_VANISHED;
+			else
+				ret = SCLD_FAILED;
+		} else if (adjust_shared_perm(path)) {
+			ret = SCLD_PERMS;
 		}
-		*pos++ = '/';
+		*slash = slash_character;
 	}
-	return 0;
+	return ret;
 }
 
-int safe_create_leading_directories_const(const char *path)
+enum scld_error safe_create_leading_directories_const(const char *path)
 {
 	/* path points to cache entries, so xstrdup before messing with it */
 	char *buf = xstrdup(path);
-	int result = safe_create_leading_directories(buf);
+	enum scld_error result = safe_create_leading_directories(buf);
 	free(buf);
 	return result;
 }
@@ -165,17 +181,7 @@ static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
 	}
 }
 
-/*
- * NOTE! This returns a statically allocated buffer, so you have to be
- * careful about using it. Do an "xstrdup()" if you need to save the
- * filename.
- *
- * Also note that this returns the location for creating.  Reading
- * SHA1 file can happen from any alternate directory listed in the
- * DB_ENVIRONMENT environment variable if it is not found in
- * the primary object database.
- */
-char *sha1_file_name(const unsigned char *sha1)
+const char *sha1_file_name(const unsigned char *sha1)
 {
 	static char buf[PATH_MAX];
 	const char *objdir;
@@ -195,6 +201,11 @@ char *sha1_file_name(const unsigned char *sha1)
 	return buf;
 }
 
+/*
+ * Return the name of the pack or index file with the specified sha1
+ * in its filename.  *base and *name are scratch space that must be
+ * provided by the caller.  which should be "pack" or "idx".
+ */
 static char *sha1_get_pack_name(const unsigned char *sha1,
 				char **name, char **base, const char *which)
 {
@@ -239,8 +250,6 @@ char *sha1_pack_index_name(const unsigned char *sha1)
 struct alternate_object_database *alt_odb_list;
 static struct alternate_object_database **alt_odb_tail;
 
-static int git_open_noatime(const char *name);
-
 /*
  * Prepare alternate object database registry.
  *
@@ -256,9 +265,9 @@ static int git_open_noatime(const char *name);
  * SHA1, an extra slash for the first level indirection, and the
  * terminating NUL.
  */
-static int link_alt_odb_entry(const char *entry, const char *relative_base, int depth)
+static int link_alt_odb_entry(const char *entry, const char *relative_base,
+	int depth, const char *normalized_objdir)
 {
-	const char *objdir = get_object_directory();
 	struct alternate_object_database *ent;
 	struct alternate_object_database *alt;
 	int pfxlen, entlen;
@@ -303,12 +312,13 @@ static int link_alt_odb_entry(const char *entry, const char *relative_base, int
 	 * thing twice, or object directory itself.
 	 */
 	for (alt = alt_odb_list; alt; alt = alt->next) {
-		if (!memcmp(ent->base, alt->base, pfxlen)) {
+		if (pfxlen == alt->name - alt->base - 1 &&
+		    !memcmp(ent->base, alt->base, pfxlen)) {
 			free(ent);
 			return -1;
 		}
 	}
-	if (!strcmp(ent->base, objdir)) {
+	if (!strcmp_icase(ent->base, normalized_objdir)) {
 		free(ent);
 		return -1;
 	}
@@ -332,6 +342,7 @@ static void link_alt_odb_entries(const char *alt, int len, int sep,
 	struct string_list entries = STRING_LIST_INIT_NODUP;
 	char *alt_copy;
 	int i;
+	struct strbuf objdirbuf = STRBUF_INIT;
 
 	if (depth > 5) {
 		error("%s: ignoring alternate object stores, nesting too deep.",
@@ -339,6 +350,9 @@ static void link_alt_odb_entries(const char *alt, int len, int sep,
 		return;
 	}
 
+	strbuf_add_absolute_path(&objdirbuf, get_object_directory());
+	normalize_path_copy(objdirbuf.buf, objdirbuf.buf);
+
 	alt_copy = xmemdupz(alt, len);
 	string_list_split_in_place(&entries, alt_copy, sep, -1);
 	for (i = 0; i < entries.nr; i++) {
@@ -349,11 +363,12 @@ static void link_alt_odb_entries(const char *alt, int len, int sep,
 			error("%s: ignoring relative alternate object store %s",
 					relative_base, entry);
 		} else {
-			link_alt_odb_entry(entry, relative_base, depth);
+			link_alt_odb_entry(entry, relative_base, depth, objdirbuf.buf);
 		}
 	}
 	string_list_clear(&entries, 0);
 	free(alt_copy);
+	strbuf_release(&objdirbuf);
 }
 
 void read_info_alternates(const char * relative_base, int depth)
@@ -425,8 +440,7 @@ void prepare_alt_odb(void)
 
 static int has_loose_object_local(const unsigned char *sha1)
 {
-	char *name = sha1_file_name(sha1);
-	return !access(name, F_OK);
+	return !access(sha1_file_name(sha1), F_OK);
 }
 
 int has_loose_object_nonlocal(const unsigned char *sha1)
@@ -478,7 +492,12 @@ void pack_report(void)
 		sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));
 }
 
-static int check_packed_git_idx(const char *path,  struct packed_git *p)
+/*
+ * Open and mmap the index file at path, perform a couple of
+ * consistency checks, then record its information to p.  Return 0 on
+ * success.
+ */
+static int check_packed_git_idx(const char *path, struct packed_git *p)
 {
 	void *idx_map;
 	struct pack_idx_header *hdr;
@@ -774,7 +793,7 @@ void close_pack_index(struct packed_git *p)
  * contain the same set of objects as an existing one.  In that case
  * the resulting file might be different even if its name would be the
  * same.  It is best to close any reference to the old pack before it is
- * replaced on disk.  Of course no index pointers nor windows for given pack
+ * replaced on disk.  Of course no index pointers or windows for given pack
  * must subsist at this point.  If ever objects from this pack are requested
  * again, the new version of the pack will be reinitialized through
  * reprepare_packed_git().
@@ -1110,7 +1129,7 @@ static void report_helper(const struct string_list *list,
 	const char *msg;
 	switch (seen_bits) {
 	case 0:
-		msg = "no corresponding .idx nor .pack";
+		msg = "no corresponding .idx or .pack";
 		break;
 	case 1:
 		msg = "no corresponding .idx";
@@ -1161,48 +1180,42 @@ static void report_pack_garbage(struct string_list *list)
 
 static void prepare_packed_git_one(char *objdir, int local)
 {
-	/* Ensure that this buffer is large enough so that we can
-	   append "/pack/" without clobbering the stack even if
-	   strlen(objdir) were PATH_MAX.  */
-	char path[PATH_MAX + 1 + 4 + 1 + 1];
-	int len;
+	struct strbuf path = STRBUF_INIT;
+	size_t dirnamelen;
 	DIR *dir;
 	struct dirent *de;
 	struct string_list garbage = STRING_LIST_INIT_DUP;
 
-	sprintf(path, "%s/pack", objdir);
-	len = strlen(path);
-	dir = opendir(path);
+	strbuf_addstr(&path, objdir);
+	strbuf_addstr(&path, "/pack");
+	dir = opendir(path.buf);
 	if (!dir) {
 		if (errno != ENOENT)
 			error("unable to open object pack directory: %s: %s",
-			      path, strerror(errno));
+			      path.buf, strerror(errno));
+		strbuf_release(&path);
 		return;
 	}
-	path[len++] = '/';
+	strbuf_addch(&path, '/');
+	dirnamelen = path.len;
 	while ((de = readdir(dir)) != NULL) {
-		int namelen = strlen(de->d_name);
 		struct packed_git *p;
-
-		if (len + namelen + 1 > sizeof(path)) {
-			if (report_garbage) {
-				struct strbuf sb = STRBUF_INIT;
-				strbuf_addf(&sb, "%.*s/%s", len - 1, path, de->d_name);
-				report_garbage("path too long", sb.buf);
-				strbuf_release(&sb);
-			}
-			continue;
-		}
+		size_t base_len;
 
 		if (is_dot_or_dotdot(de->d_name))
 			continue;
 
-		strcpy(path + len, de->d_name);
+		strbuf_setlen(&path, dirnamelen);
+		strbuf_addstr(&path, de->d_name);
 
-		if (has_extension(de->d_name, ".idx")) {
+		base_len = path.len;
+		if (strip_suffix_mem(path.buf, &base_len, ".idx")) {
 			/* Don't reopen a pack we already have. */
 			for (p = packed_git; p; p = p->next) {
-				if (!memcmp(path, p->pack_name, len + namelen - 4))
+				size_t len;
+				if (strip_suffix(p->pack_name, ".pack", &len) &&
+				    len == base_len &&
+				    !memcmp(p->pack_name, path.buf, len))
 					break;
 			}
 			if (p == NULL &&
@@ -1210,23 +1223,25 @@ static void prepare_packed_git_one(char *objdir, int local)
 			     * See if it really is a valid .idx file with
 			     * corresponding .pack file that we can map.
 			     */
-			    (p = add_packed_git(path, len + namelen, local)) != NULL)
+			    (p = add_packed_git(path.buf, path.len, local)) != NULL)
 				install_packed_git(p);
 		}
 
 		if (!report_garbage)
 			continue;
 
-		if (has_extension(de->d_name, ".idx") ||
-		    has_extension(de->d_name, ".pack") ||
-		    has_extension(de->d_name, ".keep"))
-			string_list_append(&garbage, path);
+		if (ends_with(de->d_name, ".idx") ||
+		    ends_with(de->d_name, ".pack") ||
+		    ends_with(de->d_name, ".bitmap") ||
+		    ends_with(de->d_name, ".keep"))
+			string_list_append(&garbage, path.buf);
 		else
-			report_garbage("garbage found", path);
+			report_garbage("garbage found", path.buf);
 	}
 	closedir(dir);
 	report_pack_garbage(&garbage);
 	string_list_clear(&garbage, 0);
+	strbuf_release(&path);
 }
 
 static int sort_pack(const void *a_, const void *b_)
@@ -1303,7 +1318,6 @@ void prepare_packed_git(void)
 
 void reprepare_packed_git(void)
 {
-	discard_revindex();
 	prepare_packed_git_run_once = 0;
 	prepare_packed_git();
 }
@@ -1380,7 +1394,7 @@ int check_sha1_signature(const unsigned char *sha1, void *map,
 	return hashcmp(sha1, real_sha1) ? -1 : 0;
 }
 
-static int git_open_noatime(const char *name)
+int git_open_noatime(const char *name)
 {
 	static int sha1_file_open_flag = O_NOATIME;
 
@@ -1401,17 +1415,15 @@ static int git_open_noatime(const char *name)
 
 static int stat_sha1_file(const unsigned char *sha1, struct stat *st)
 {
-	char *name = sha1_file_name(sha1);
 	struct alternate_object_database *alt;
 
-	if (!lstat(name, st))
+	if (!lstat(sha1_file_name(sha1), st))
 		return 0;
 
 	prepare_alt_odb();
 	errno = ENOENT;
 	for (alt = alt_odb_list; alt; alt = alt->next) {
-		name = alt->name;
-		fill_sha1_path(name, sha1);
+		fill_sha1_path(alt->name, sha1);
 		if (!lstat(alt->base, st))
 			return 0;
 	}
@@ -1422,22 +1434,24 @@ static int stat_sha1_file(const unsigned char *sha1, struct stat *st)
 static int open_sha1_file(const unsigned char *sha1)
 {
 	int fd;
-	char *name = sha1_file_name(sha1);
 	struct alternate_object_database *alt;
+	int most_interesting_errno;
 
-	fd = git_open_noatime(name);
+	fd = git_open_noatime(sha1_file_name(sha1));
 	if (fd >= 0)
 		return fd;
+	most_interesting_errno = errno;
 
 	prepare_alt_odb();
-	errno = ENOENT;
 	for (alt = alt_odb_list; alt; alt = alt->next) {
-		name = alt->name;
-		fill_sha1_path(name, sha1);
+		fill_sha1_path(alt->name, sha1);
 		fd = git_open_noatime(alt->base);
 		if (fd >= 0)
 			return fd;
+		if (most_interesting_errno == ENOENT)
+			most_interesting_errno = errno;
 	}
+	errno = most_interesting_errno;
 	return -1;
 }
 
@@ -1465,51 +1479,6 @@ void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 	return map;
 }
 
-/*
- * There used to be a second loose object header format which
- * was meant to mimic the in-pack format, allowing for direct
- * copy of the object data.  This format turned up not to be
- * really worth it and we no longer write loose objects in that
- * format.
- */
-static int experimental_loose_object(unsigned char *map)
-{
-	unsigned int word;
-
-	/*
-	 * We must determine if the buffer contains the standard
-	 * zlib-deflated stream or the experimental format based
-	 * on the in-pack object format. Compare the header byte
-	 * for each format:
-	 *
-	 * RFC1950 zlib w/ deflate : 0www1000 : 0 <= www <= 7
-	 * Experimental pack-based : Stttssss : ttt = 1,2,3,4
-	 *
-	 * If bit 7 is clear and bits 0-3 equal 8, the buffer MUST be
-	 * in standard loose-object format, UNLESS it is a Git-pack
-	 * format object *exactly* 8 bytes in size when inflated.
-	 *
-	 * However, RFC1950 also specifies that the 1st 16-bit word
-	 * must be divisible by 31 - this checksum tells us our buffer
-	 * is in the standard format, giving a false positive only if
-	 * the 1st word of the Git-pack format object happens to be
-	 * divisible by 31, ie:
-	 *      ((byte0 * 256) + byte1) % 31 = 0
-	 *   =>        0ttt10000www1000 % 31 = 0
-	 *
-	 * As it happens, this case can only arise for www=3 & ttt=1
-	 * - ie, a Commit object, which would have to be 8 bytes in
-	 * size. As no Commit can be that small, we find that the
-	 * combination of these two criteria (bitmask & checksum)
-	 * can always correctly determine the buffer format.
-	 */
-	word = (map[0] << 8) + map[1];
-	if ((map[0] & 0x8F) == 0x08 && !(word % 31))
-		return 0;
-	else
-		return 1;
-}
-
 unsigned long unpack_object_header_buffer(const unsigned char *buf,
 		unsigned long len, enum object_type *type, unsigned long *sizep)
 {
@@ -1537,14 +1506,6 @@ unsigned long unpack_object_header_buffer(const unsigned char *buf,
 
 int unpack_sha1_header(git_zstream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
 {
-	unsigned long size, used;
-	static const char valid_loose_object_type[8] = {
-		0, /* OBJ_EXT */
-		1, 1, 1, 1, /* "commit", "tree", "blob", "tag" */
-		0, /* "delta" and others are invalid in a loose object */
-	};
-	enum object_type type;
-
 	/* Get the data stream */
 	memset(stream, 0, sizeof(*stream));
 	stream->next_in = map;
@@ -1552,27 +1513,6 @@ int unpack_sha1_header(git_zstream *stream, unsigned char *map, unsigned long ma
 	stream->next_out = buffer;
 	stream->avail_out = bufsiz;
 
-	if (experimental_loose_object(map)) {
-		/*
-		 * The old experimental format we no longer produce;
-		 * we can still read it.
-		 */
-		used = unpack_object_header_buffer(map, mapsize, &type, &size);
-		if (!used || !valid_loose_object_type[type])
-			return -1;
-		map += used;
-		mapsize -= used;
-
-		/* Set up the stream for the rest.. */
-		stream->next_in = map;
-		stream->avail_in = mapsize;
-		git_inflate_init(stream);
-
-		/* And generate the fake traditional header */
-		stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu",
-						 typename(type), size);
-		return 0;
-	}
 	git_inflate_init(stream);
 	return git_inflate(stream, 0);
 }
@@ -1764,6 +1704,38 @@ static off_t get_delta_base(struct packed_git *p,
 	return base_offset;
 }
 
+/*
+ * Like get_delta_base above, but we return the sha1 instead of the pack
+ * offset. This means it is cheaper for REF deltas (we do not have to do
+ * the final object lookup), but more expensive for OFS deltas (we
+ * have to load the revidx to convert the offset back into a sha1).
+ */
+static const unsigned char *get_delta_base_sha1(struct packed_git *p,
+						struct pack_window **w_curs,
+						off_t curpos,
+						enum object_type type,
+						off_t delta_obj_offset)
+{
+	if (type == OBJ_REF_DELTA) {
+		unsigned char *base = use_pack(p, w_curs, curpos, NULL);
+		return base;
+	} else if (type == OBJ_OFS_DELTA) {
+		struct revindex_entry *revidx;
+		off_t base_offset = get_delta_base(p, w_curs, &curpos,
+						   type, delta_obj_offset);
+
+		if (!base_offset)
+			return NULL;
+
+		revidx = find_pack_revindex(p, base_offset);
+		if (!revidx)
+			return NULL;
+
+		return nth_packed_object_sha1(p, revidx->nr);
+	} else
+		return NULL;
+}
+
 int unpack_object_header(struct packed_git *p,
 			 struct pack_window **w_curs,
 			 off_t *curpos,
@@ -1921,6 +1893,22 @@ static int packed_object_info(struct packed_git *p, off_t obj_offset,
 		}
 	}
 
+	if (oi->delta_base_sha1) {
+		if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
+			const unsigned char *base;
+
+			base = get_delta_base_sha1(p, &w_curs, curpos,
+						   type, obj_offset);
+			if (!base) {
+				type = OBJ_BAD;
+				goto out;
+			}
+
+			hashcpy(oi->delta_base_sha1, base);
+		} else
+			hashclr(oi->delta_base_sha1);
+	}
+
 out:
 	unuse_pack(&w_curs);
 	return type;
@@ -1935,7 +1923,9 @@ static void *unpack_compressed_entry(struct packed_git *p,
 	git_zstream stream;
 	unsigned char *buffer, *in;
 
-	buffer = xmallocz(size);
+	buffer = xmallocz_gently(size);
+	if (!buffer)
+		return NULL;
 	memset(&stream, 0, sizeof(stream));
 	stream.next_out = buffer;
 	stream.avail_out = size + 1;
@@ -2095,27 +2085,9 @@ static void *read_object(const unsigned char *sha1, enum object_type *type,
 
 static void write_pack_access_log(struct packed_git *p, off_t obj_offset)
 {
-	static FILE *log_file;
-
-	if (!log_pack_access)
-		log_pack_access = getenv("GIT_TRACE_PACK_ACCESS");
-	if (!log_pack_access)
-		log_pack_access = no_log_pack_access;
-	if (log_pack_access == no_log_pack_access)
-		return;
-
-	if (!log_file) {
-		log_file = fopen(log_pack_access, "w");
-		if (!log_file) {
-			error("cannot open pack access log '%s' for writing: %s",
-			      log_pack_access, strerror(errno));
-			log_pack_access = no_log_pack_access;
-			return;
-		}
-	}
-	fprintf(log_file, "%s %"PRIuMAX"\n",
-		p->pack_name, (uintmax_t)obj_offset);
-	fflush(log_file);
+	static struct trace_key pack_access = TRACE_KEY_INIT(PACK_ACCESS);
+	trace_printf_key(&pack_access, "%s %"PRIuMAX"\n",
+			 p->pack_name, (uintmax_t)obj_offset);
 }
 
 int do_check_packed_object_crc;
@@ -2140,8 +2112,7 @@ void *unpack_entry(struct packed_git *p, off_t obj_offset,
 	int delta_stack_nr = 0, delta_stack_alloc = UNPACK_ENTRY_STACK_PREALLOC;
 	int base_from_cache = 0;
 
-	if (log_pack_access != no_log_pack_access)
-		write_pack_access_log(p, obj_offset);
+	write_pack_access_log(p, obj_offset);
 
 	/* PHASE 1: drill down to the innermost base object */
 	for (;;) {
@@ -2302,6 +2273,10 @@ void *unpack_entry(struct packed_git *p, off_t obj_offset,
 	*final_size = size;
 
 	unuse_pack(&w_curs);
+
+	if (delta_stack != small_delta_stack)
+		free(delta_stack);
+
 	return data;
 }
 
@@ -2461,6 +2436,10 @@ static int fill_pack_entry(const unsigned char *sha1,
 	return 1;
 }
 
+/*
+ * Iff a pack file contains the object named by sha1, return true and
+ * store its location to e.
+ */
 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
 {
 	struct packed_git *p;
@@ -2473,11 +2452,13 @@ static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
 		return 1;
 
 	for (p = packed_git; p; p = p->next) {
-		if (p == last_found_pack || !fill_pack_entry(sha1, e, p))
-			continue;
+		if (p == last_found_pack)
+			continue; /* we already checked this one */
 
-		last_found_pack = p;
-		return 1;
+		if (fill_pack_entry(sha1, e, p)) {
+			last_found_pack = p;
+			return 1;
+		}
 	}
 	return 0;
 }
@@ -2504,6 +2485,9 @@ static int sha1_loose_object_info(const unsigned char *sha1,
 	git_zstream stream;
 	char hdr[32];
 
+	if (oi->delta_base_sha1)
+		hashclr(oi->delta_base_sha1);
+
 	/*
 	 * If we don't care about type or size, then we don't
 	 * need to look inside the object at all. Note that we
@@ -2540,13 +2524,14 @@ static int sha1_loose_object_info(const unsigned char *sha1,
 	return 0;
 }
 
-int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi)
+int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi, unsigned flags)
 {
 	struct cached_object *co;
 	struct pack_entry e;
 	int rtype;
+	const unsigned char *real = lookup_replace_object_extended(sha1, flags);
 
-	co = find_cached_object(sha1);
+	co = find_cached_object(real);
 	if (co) {
 		if (oi->typep)
 			*(oi->typep) = co->type;
@@ -2554,27 +2539,29 @@ int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi)
 			*(oi->sizep) = co->size;
 		if (oi->disk_sizep)
 			*(oi->disk_sizep) = 0;
+		if (oi->delta_base_sha1)
+			hashclr(oi->delta_base_sha1);
 		oi->whence = OI_CACHED;
 		return 0;
 	}
 
-	if (!find_pack_entry(sha1, &e)) {
+	if (!find_pack_entry(real, &e)) {
 		/* Most likely it's a loose object. */
-		if (!sha1_loose_object_info(sha1, oi)) {
+		if (!sha1_loose_object_info(real, oi)) {
 			oi->whence = OI_LOOSE;
 			return 0;
 		}
 
 		/* Not a loose object; someone else may have just packed it. */
 		reprepare_packed_git();
-		if (!find_pack_entry(sha1, &e))
+		if (!find_pack_entry(real, &e))
 			return -1;
 	}
 
 	rtype = packed_object_info(e.p, e.offset, oi);
 	if (rtype < 0) {
-		mark_bad_packed_object(e.p, sha1);
-		return sha1_object_info_extended(sha1, oi);
+		mark_bad_packed_object(e.p, real);
+		return sha1_object_info_extended(real, oi, 0);
 	} else if (in_delta_base_cache(e.p, e.offset)) {
 		oi->whence = OI_DBCACHED;
 	} else {
@@ -2596,7 +2583,7 @@ int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
 
 	oi.typep = &type;
 	oi.sizep = sizep;
-	if (sha1_object_info_extended(sha1, &oi) < 0)
+	if (sha1_object_info_extended(sha1, &oi, LOOKUP_REPLACE_OBJECT) < 0)
 		return -1;
 	return type;
 }
@@ -2633,12 +2620,7 @@ int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
 	hash_sha1_file(buf, len, typename(type), sha1);
 	if (has_sha1_file(sha1) || find_cached_object(sha1))
 		return 0;
-	if (cached_object_alloc <= cached_object_nr) {
-		cached_object_alloc = alloc_nr(cached_object_alloc);
-		cached_objects = xrealloc(cached_objects,
-					  sizeof(*cached_objects) *
-					  cached_object_alloc);
-	}
+	ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);
 	co = &cached_objects[cached_object_nr++];
 	co->size = len;
 	co->type = type;
@@ -2686,10 +2668,8 @@ void *read_sha1_file_extended(const unsigned char *sha1,
 			      unsigned flag)
 {
 	void *data;
-	char *path;
 	const struct packed_git *p;
-	const unsigned char *repl = (flag & READ_SHA1_FILE_REPLACE)
-		? lookup_replace_object(sha1) : sha1;
+	const unsigned char *repl = lookup_replace_object_extended(sha1, flag);
 
 	errno = 0;
 	data = read_object(repl, type, size);
@@ -2705,7 +2685,8 @@ void *read_sha1_file_extended(const unsigned char *sha1,
 		    sha1_to_hex(repl), sha1_to_hex(sha1));
 
 	if (has_loose_object(repl)) {
-		path = sha1_file_name(sha1);
+		const char *path = sha1_file_name(sha1);
+
 		die("loose object %s (stored in %s) is corrupt",
 		    sha1_to_hex(repl), path);
 	}
@@ -2903,10 +2884,9 @@ static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
 	git_zstream stream;
 	git_SHA_CTX c;
 	unsigned char parano_sha1[20];
-	char *filename;
 	static char tmp_file[PATH_MAX];
+	const char *filename = sha1_file_name(sha1);
 
-	filename = sha1_file_name(sha1);
 	fd = create_tmpfile(tmp_file, sizeof(tmp_file), filename);
 	if (fd < 0) {
 		if (errno == EACCES)