https://github.com/git/git
Revision a36df79a37c7c643177905ce725dca8e9bd092d3 authored by Jeff King on 09 August 2021, 22:48:39 UTC, committed by Johannes Schindelin on 12 March 2023, 19:31:55 UTC
When parsing our buffer of output from git-log, we have a
find_end_of_line() helper that finds the next newline, and gives us the
number of bytes to move past it, or the size of the whole remaining
buffer if there is no newline.

But trying to handle both those cases leads to some oddities:

  - we try to overwrite the newline with NUL in the caller, by writing
    over line[len-1]. This is at best redundant, since the helper will
    already have done so if it saw a newline. But if it didn't see a
    newline, it's actively wrong; we'll overwrite the byte at the end of
    the (unterminated) line.

    We could solve this just dropping the extra NUL assignment in the
    caller and just letting the helper do the right thing. But...

  - if we see a "diff --git" line, we'll restore the newline on top of
    the NUL byte, so we can pass the string to parse_git_diff_header().
    But if there was no newline in the first place, we can't do this.
    There's no place to put it (the current code writes a newline
    over whatever byte we obliterated earlier). The best we can do is
    feed the complete remainder of the buffer to the function (which is,
    in fact, a string, by virtue of being a strbuf).

To solve this, the caller needs to know whether we actually found a
newline or not. We could modify find_end_of_line() to return that
information, but we can further observe that it has only one caller.
So let's just inline it in that caller.

Nobody seems to have noticed this case, probably because git-log would
never produce input that doesn't end with a newline. Arguably we could
just return an error as soon as we see that the output does not end in a
newline. But the code to do so actually ends up _longer_, mostly because
of the cleanup we have to do in handling the error.

Signed-off-by: Jeff King <peff@peff.net>
Acked-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 18bc8eb
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Tip revision: a36df79a37c7c643177905ce725dca8e9bd092d3 authored by Jeff King on 09 August 2021, 22:48:39 UTC
range-diff: handle unterminated lines in read_patches()
Tip revision: a36df79
pack-bitmap.h
#ifndef PACK_BITMAP_H
#define PACK_BITMAP_H

#include "ewah/ewok.h"
#include "khash.h"
#include "pack.h"
#include "pack-objects.h"

struct commit;
struct repository;
struct rev_info;
struct list_objects_filter_options;

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 *,
				 struct rev_info *revs,
				 show_reachable_fn show_reachable);
void test_bitmap_walk(struct rev_info *revs);
struct bitmap_index *prepare_bitmap_walk(struct rev_info *revs,
					 struct list_objects_filter_options *filter);
int reuse_partial_packfile_from_bitmap(struct bitmap_index *,
				       struct packed_git **packfile,
				       uint32_t *entries,
				       struct bitmap **reuse_out);
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 *);
int bitmap_walk_contains(struct bitmap_index *,
			 struct bitmap *bitmap, const struct object_id *oid);

/*
 * 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
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