git/pack-bitmap.h
Denton Liu af26e2a9d2 pack-bitmap.h: remove magic number
When we ran `make hdr-check` with the following patch

	diff --git a/Makefile b/Makefile
	index f879697ea3..d8df4e316b 100644
	--- a/Makefile
	+++ b/Makefile
	@@ -2773,7 +2773,7 @@ CHK_HDRS = $(filter-out $(EXCEPT_HDRS),$(patsubst ./%,%,$(LIB_H)))
	HCO = $(patsubst %.h,%.hco,$(CHK_HDRS))

	$(HCO): %.hco: %.h FORCE
	-	$(QUIET_HDR)$(CC) -include git-compat-util.h -I. -o /dev/null -c -xc $<
	+	$(QUIET_HDR)$(CC) -include git-compat-util.h -I. -o /dev/null -c -xc $(ALL_CFLAGS) $<

	.PHONY: hdr-check $(HCO)
	hdr-check: $(HCO)

and with `DEVELOPER=1`, we got the following warning on Arch Linux:

	pack-bitmap.h:20:19: error: ‘BITMAP_IDX_SIGNATURE’ defined but not used [-Werror=unused-const-variable=]
	   20 | static const char BITMAP_IDX_SIGNATURE[] = {'B', 'I', 'T', 'M'};
	      |                   ^~~~~~~~~~~~~~~~~~~~
	cc1: all warnings being treated as errors

"Use" the BITMAP_IDX_SIGNATURE variable by making the size of
bitmap_disk_header.magic equal to the size of BITMAP_IDX_SIGNATURE,
thereby eliminating the magic number (4).

An alternative was to simply add MAYBE_UNUSED, however that does not
eliminate the magic number.

Another alternative was to change the definition to

	extern const char BITMAP_IDX_SIGNATURE[4];

However, this design was also not chosen as the static definition allows
us to keep the declaration together for readability along with removing
the magic number.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-09-28 14:04:20 +09:00

79 lines
2.3 KiB
C

#ifndef PACK_BITMAP_H
#define PACK_BITMAP_H
#include "ewah/ewok.h"
#include "khash.h"
#include "pack-objects.h"
struct commit;
struct repository;
struct rev_info;
static const char BITMAP_IDX_SIGNATURE[] = {'B', 'I', 'T', 'M'};
struct bitmap_disk_header {
char magic[ARRAY_SIZE(BITMAP_IDX_SIGNATURE)];
uint16_t version;
uint16_t options;
uint32_t entry_count;
unsigned char checksum[GIT_MAX_RAWSZ];
};
#define NEEDS_BITMAP (1u<<22)
enum pack_bitmap_opts {
BITMAP_OPT_FULL_DAG = 1,
BITMAP_OPT_HASH_CACHE = 4,
};
enum pack_bitmap_flags {
BITMAP_FLAG_REUSE = 0x1
};
typedef int (*show_reachable_fn)(
const struct object_id *oid,
enum object_type type,
int flags,
uint32_t hash,
struct packed_git *found_pack,
off_t found_offset);
struct bitmap_index;
struct bitmap_index *prepare_bitmap_git(struct repository *r);
void count_bitmap_commit_list(struct bitmap_index *, uint32_t *commits,
uint32_t *trees, uint32_t *blobs, uint32_t *tags);
void traverse_bitmap_commit_list(struct bitmap_index *,
show_reachable_fn show_reachable);
void test_bitmap_walk(struct rev_info *revs);
struct bitmap_index *prepare_bitmap_walk(struct rev_info *revs);
int reuse_partial_packfile_from_bitmap(struct bitmap_index *,
struct packed_git **packfile,
uint32_t *entries, off_t *up_to);
int rebuild_existing_bitmaps(struct bitmap_index *, struct packing_data *mapping,
kh_oid_map_t *reused_bitmaps, int show_progress);
void free_bitmap_index(struct bitmap_index *);
/*
* After a traversal has been performed by prepare_bitmap_walk(), this can be
* queried to see if a particular object was reachable from any of the
* objects flagged as UNINTERESTING.
*/
int bitmap_has_oid_in_uninteresting(struct bitmap_index *, const struct object_id *oid);
void bitmap_writer_show_progress(int show);
void bitmap_writer_set_checksum(unsigned char *sha1);
void bitmap_writer_build_type_index(struct packing_data *to_pack,
struct pack_idx_entry **index,
uint32_t index_nr);
void bitmap_writer_reuse_bitmaps(struct packing_data *to_pack);
void bitmap_writer_select_commits(struct commit **indexed_commits,
unsigned int indexed_commits_nr, int max_bitmaps);
void bitmap_writer_build(struct packing_data *to_pack);
void bitmap_writer_finish(struct pack_idx_entry **index,
uint32_t index_nr,
const char *filename,
uint16_t options);
#endif