git/commit.h
Jeff King 218aa3a616 reuse cached commit buffer when parsing signatures
When we call show_signature or show_mergetag, we read the
commit object fresh via read_sha1_file and reparse its
headers. However, in most cases we already have the object
data available, attached to the "struct commit". This is
partially laziness in dealing with the memory allocation
issues, but partially defensive programming, in that we
would always want to verify a clean version of the buffer
(not one that might have been munged by other users of the
commit).

However, we do not currently ever munge the commit buffer,
and not using the already-available buffer carries a fairly
big performance penalty when we are looking at a large
number of commits. Here are timings on linux.git:

  [baseline, no signatures]
  $ time git log >/dev/null
  real    0m4.902s
  user    0m4.784s
  sys     0m0.120s

  [before]
  $ time git log --show-signature >/dev/null
  real    0m14.735s
  user    0m9.964s
  sys     0m0.944s

  [after]
  $ time git log --show-signature >/dev/null
  real    0m9.981s
  user    0m5.260s
  sys     0m0.936s

Note that our user CPU time drops almost in half, close to
the non-signature case, but we do still spend more
wall-clock and system time, presumably from dealing with
gpg.

An alternative to this is to note that most commits do not
have signatures (less than 1% in this repo), yet we pay the
re-parsing cost for every commit just to find out if it has
a mergetag or signature. If we checked that when parsing the
commit initially, we could avoid re-examining most commits
later on. Even if we did pursue that direction, however,
this would still speed up the cases where we _do_ have
signatures. So it's probably worth doing either way.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-06-13 12:10:13 -07:00

349 lines
12 KiB
C

#ifndef COMMIT_H
#define COMMIT_H
#include "object.h"
#include "tree.h"
#include "strbuf.h"
#include "decorate.h"
#include "gpg-interface.h"
#include "string-list.h"
struct commit_list {
struct commit *item;
struct commit_list *next;
};
struct commit {
struct object object;
void *util;
unsigned int index;
unsigned long date;
struct commit_list *parents;
struct tree *tree;
};
extern int save_commit_buffer;
extern const char *commit_type;
/* While we can decorate any object with a name, it's only used for commits.. */
extern struct decoration name_decoration;
struct name_decoration {
struct name_decoration *next;
int type;
char name[1];
};
struct commit *lookup_commit(const unsigned char *sha1);
struct commit *lookup_commit_reference(const unsigned char *sha1);
struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
int quiet);
struct commit *lookup_commit_reference_by_name(const char *name);
/*
* Look up object named by "sha1", dereference tag as necessary,
* get a commit and return it. If "sha1" does not dereference to
* a commit, use ref_name to report an error and die.
*/
struct commit *lookup_commit_or_die(const unsigned char *sha1, const char *ref_name);
int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size);
int parse_commit(struct commit *item);
void parse_commit_or_die(struct commit *item);
/*
* Associate an object buffer with the commit. The ownership of the
* memory is handed over to the commit, and must be free()-able.
*/
void set_commit_buffer(struct commit *, void *buffer, unsigned long size);
/*
* Get any cached object buffer associated with the commit. Returns NULL
* if none. The resulting memory should not be freed.
*/
const void *get_cached_commit_buffer(const struct commit *, unsigned long *size);
/*
* Get the commit's object contents, either from cache or by reading the object
* from disk. The resulting memory should not be modified, and must be given
* to unuse_commit_buffer when the caller is done.
*/
const void *get_commit_buffer(const struct commit *, unsigned long *size);
/*
* Tell the commit subsytem that we are done with a particular commit buffer.
* The commit and buffer should be the input and return value, respectively,
* from an earlier call to get_commit_buffer. The buffer may or may not be
* freed by this call; callers should not access the memory afterwards.
*/
void unuse_commit_buffer(const struct commit *, const void *buffer);
/*
* Free any cached object buffer associated with the commit.
*/
void free_commit_buffer(struct commit *);
/*
* Disassociate any cached object buffer from the commit, but do not free it.
* The buffer (or NULL, if none) is returned.
*/
const void *detach_commit_buffer(struct commit *, unsigned long *sizep);
/* Find beginning and length of commit subject. */
int find_commit_subject(const char *commit_buffer, const char **subject);
struct commit_list *commit_list_insert(struct commit *item,
struct commit_list **list);
struct commit_list **commit_list_append(struct commit *commit,
struct commit_list **next);
unsigned commit_list_count(const struct commit_list *l);
struct commit_list *commit_list_insert_by_date(struct commit *item,
struct commit_list **list);
void commit_list_sort_by_date(struct commit_list **list);
/* Shallow copy of the input list */
struct commit_list *copy_commit_list(struct commit_list *list);
void free_commit_list(struct commit_list *list);
/* Commit formats */
enum cmit_fmt {
CMIT_FMT_RAW,
CMIT_FMT_MEDIUM,
CMIT_FMT_DEFAULT = CMIT_FMT_MEDIUM,
CMIT_FMT_SHORT,
CMIT_FMT_FULL,
CMIT_FMT_FULLER,
CMIT_FMT_ONELINE,
CMIT_FMT_EMAIL,
CMIT_FMT_USERFORMAT,
CMIT_FMT_UNSPECIFIED
};
struct pretty_print_context {
/*
* Callers should tweak these to change the behavior of pp_* functions.
*/
enum cmit_fmt fmt;
int abbrev;
const char *subject;
const char *after_subject;
int preserve_subject;
enum date_mode date_mode;
unsigned date_mode_explicit:1;
int need_8bit_cte;
char *notes_message;
struct reflog_walk_info *reflog_info;
const char *output_encoding;
struct string_list *mailmap;
int color;
struct ident_split *from_ident;
/*
* Fields below here are manipulated internally by pp_* functions and
* should not be counted on by callers.
*/
struct string_list in_body_headers;
};
struct userformat_want {
unsigned notes:1;
};
extern int has_non_ascii(const char *text);
struct rev_info; /* in revision.h, it circularly uses enum cmit_fmt */
extern const char *logmsg_reencode(const struct commit *commit,
char **commit_encoding,
const char *output_encoding);
extern void get_commit_format(const char *arg, struct rev_info *);
extern const char *format_subject(struct strbuf *sb, const char *msg,
const char *line_separator);
extern void userformat_find_requirements(const char *fmt, struct userformat_want *w);
extern void format_commit_message(const struct commit *commit,
const char *format, struct strbuf *sb,
const struct pretty_print_context *context);
extern void pretty_print_commit(struct pretty_print_context *pp,
const struct commit *commit,
struct strbuf *sb);
extern void pp_commit_easy(enum cmit_fmt fmt, const struct commit *commit,
struct strbuf *sb);
void pp_user_info(struct pretty_print_context *pp,
const char *what, struct strbuf *sb,
const char *line, const char *encoding);
void pp_title_line(struct pretty_print_context *pp,
const char **msg_p,
struct strbuf *sb,
const char *encoding,
int need_8bit_cte);
void pp_remainder(struct pretty_print_context *pp,
const char **msg_p,
struct strbuf *sb,
int indent);
/** Removes the first commit from a list sorted by date, and adds all
* of its parents.
**/
struct commit *pop_most_recent_commit(struct commit_list **list,
unsigned int mark);
struct commit *pop_commit(struct commit_list **stack);
void clear_commit_marks(struct commit *commit, unsigned int mark);
void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark);
void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark);
enum rev_sort_order {
REV_SORT_IN_GRAPH_ORDER = 0,
REV_SORT_BY_COMMIT_DATE,
REV_SORT_BY_AUTHOR_DATE
};
/*
* Performs an in-place topological sort of list supplied.
*
* invariant of resulting list is:
* a reachable from b => ord(b) < ord(a)
* sort_order further specifies:
* REV_SORT_IN_GRAPH_ORDER: try to show a commit on a single-parent
* chain together.
* REV_SORT_BY_COMMIT_DATE: show eligible commits in committer-date order.
*/
void sort_in_topological_order(struct commit_list **, enum rev_sort_order);
struct commit_graft {
unsigned char sha1[20];
int nr_parent; /* < 0 if shallow commit */
unsigned char parent[FLEX_ARRAY][20]; /* more */
};
typedef int (*each_commit_graft_fn)(const struct commit_graft *, void *);
struct commit_graft *read_graft_line(char *buf, int len);
int register_commit_graft(struct commit_graft *, int);
struct commit_graft *lookup_commit_graft(const unsigned char *sha1);
extern struct commit_list *get_merge_bases(struct commit *rev1, struct commit *rev2, int cleanup);
extern struct commit_list *get_merge_bases_many(struct commit *one, int n, struct commit **twos, int cleanup);
extern struct commit_list *get_octopus_merge_bases(struct commit_list *in);
/* largest positive number a signed 32-bit integer can contain */
#define INFINITE_DEPTH 0x7fffffff
struct sha1_array;
struct ref;
extern int register_shallow(const unsigned char *sha1);
extern int unregister_shallow(const unsigned char *sha1);
extern int for_each_commit_graft(each_commit_graft_fn, void *);
extern int is_repository_shallow(void);
extern struct commit_list *get_shallow_commits(struct object_array *heads,
int depth, int shallow_flag, int not_shallow_flag);
extern void check_shallow_file_for_update(void);
extern void set_alternate_shallow_file(const char *path, int override);
extern int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
const struct sha1_array *extra);
extern void setup_alternate_shallow(struct lock_file *shallow_lock,
const char **alternate_shallow_file,
const struct sha1_array *extra);
extern const char *setup_temporary_shallow(const struct sha1_array *extra);
extern void advertise_shallow_grafts(int);
struct shallow_info {
struct sha1_array *shallow;
int *ours, nr_ours;
int *theirs, nr_theirs;
struct sha1_array *ref;
/* for receive-pack */
uint32_t **used_shallow;
int *need_reachability_test;
int *reachable;
int *shallow_ref;
struct commit **commits;
int nr_commits;
};
extern void prepare_shallow_info(struct shallow_info *, struct sha1_array *);
extern void clear_shallow_info(struct shallow_info *);
extern void remove_nonexistent_theirs_shallow(struct shallow_info *);
extern void assign_shallow_commits_to_refs(struct shallow_info *info,
uint32_t **used,
int *ref_status);
extern int delayed_reachability_test(struct shallow_info *si, int c);
extern void prune_shallow(int show_only);
int is_descendant_of(struct commit *, struct commit_list *);
int in_merge_bases(struct commit *, struct commit *);
int in_merge_bases_many(struct commit *, int, struct commit **);
extern int interactive_add(int argc, const char **argv, const char *prefix, int patch);
extern int run_add_interactive(const char *revision, const char *patch_mode,
const struct pathspec *pathspec);
static inline int single_parent(struct commit *commit)
{
return commit->parents && !commit->parents->next;
}
struct commit_list *reduce_heads(struct commit_list *heads);
struct commit_extra_header {
struct commit_extra_header *next;
char *key;
char *value;
size_t len;
};
extern void append_merge_tag_headers(struct commit_list *parents,
struct commit_extra_header ***tail);
extern int commit_tree(const char *msg, size_t msg_len,
const unsigned char *tree,
struct commit_list *parents, unsigned char *ret,
const char *author, const char *sign_commit);
extern int commit_tree_extended(const char *msg, size_t msg_len,
const unsigned char *tree,
struct commit_list *parents, unsigned char *ret,
const char *author, const char *sign_commit,
struct commit_extra_header *);
extern struct commit_extra_header *read_commit_extra_headers(struct commit *, const char **);
extern void free_commit_extra_headers(struct commit_extra_header *extra);
struct merge_remote_desc {
struct object *obj; /* the named object, could be a tag */
const char *name;
};
#define merge_remote_util(commit) ((struct merge_remote_desc *)((commit)->util))
/*
* Given "name" from the command line to merge, find the commit object
* and return it, while storing merge_remote_desc in its ->util field,
* to allow callers to tell if we are told to merge a tag.
*/
struct commit *get_merge_parent(const char *name);
extern int parse_signed_commit(const struct commit *commit,
struct strbuf *message, struct strbuf *signature);
extern void print_commit_list(struct commit_list *list,
const char *format_cur,
const char *format_last);
/*
* Check the signature of the given commit. The result of the check is stored
* in sig->check_result, 'G' for a good signature, 'U' for a good signature
* from an untrusted signer, 'B' for a bad signature and 'N' for no signature
* at all. This may allocate memory for sig->gpg_output, sig->gpg_status,
* sig->signer and sig->key.
*/
extern void check_commit_signature(const struct commit* commit, struct signature_check *sigc);
int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused);
LAST_ARG_MUST_BE_NULL
extern int run_commit_hook(int editor_is_used, const char *index_file, const char *name, ...);
#endif /* COMMIT_H */