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git/commit-reach.h
Ramsay Jones 1406725b88 commit-reach.h: add missing declarations (hdr-check)
Add the necessary #includes and forward declarations to allow the header
file to pass the 'hdr-check' target.

Note that, since this header includes the commit-slab implementation
header file (indirectly via commit-slab.h), some of the commit-slab
inline functions (e.g contains_cache_at_peek()) will not compile without
the complete type of 'struct commit'. Hence, we replace the forward
declaration of 'struct commit' with the an #include of the 'commit.h'
header file.

It is possible, using the 'commit-slab-{decl,impl}.h' files, to avoid
this inclusion of the 'commit.h' header. Commit a9f1f1f9f8 ("commit-slab.h:
code split", 2018-05-19) separated the commit-slab interface from its
implementation, to allow for the definition of a public commit-slab data
structure. This enabled us to avoid including the commit-slab implementation
in a header file, which could result in the replication of the commit-slab
functions in each compilation unit in which it was included.

Indeed, if you compile with optimizations disabled, then run this script:

  $ cat -n dup-static.sh
       1 #!/bin/sh
       2
       3 nm $1 | grep ' t ' | cut -d' ' -f3 | sort | uniq -c |
       4 	sort -rn | grep -v '      1'
  $

  $ ./dup-static.sh git | grep contains
       24 init_contains_cache_with_stride
       24 init_contains_cache
       24 contains_cache_peek
       24 contains_cache_at_peek
       24 contains_cache_at
       24 clear_contains_cache
  $

you will find 24 copies of the commit-slab routines for the contains_cache.
Of course, when you enable optimizations again, these duplicate static
functions (mostly) disappear. Compiling with gcc at -O2, leaves two static
functions, thus:

  $ nm commit-reach.o | grep contains_cache
  0000000000000870 t contains_cache_at_peek.isra.1.constprop.6
  $ nm ref-filter.o | grep contains_cache
  00000000000002b0 t clear_contains_cache.isra.14
  $

However, using a shared 'contains_cache' would result in all six of the
above functions as external public functions in the git binary. At present,
only three of these functions are actually called, so the trade-off
seems to favour letting the compiler inline the commit-slab functions.

Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-10-29 10:14:21 +09:00

78 lines
2.6 KiB
C

#ifndef __COMMIT_REACH_H__
#define __COMMIT_REACH_H__
#include "commit.h"
#include "commit-slab.h"
struct commit_list;
struct ref_filter;
struct object_id;
struct object_array;
struct commit_list *get_merge_bases_many(struct commit *one,
int n,
struct commit **twos);
struct commit_list *get_merge_bases_many_dirty(struct commit *one,
int n,
struct commit **twos);
struct commit_list *get_merge_bases(struct commit *one, struct commit *two);
struct commit_list *get_octopus_merge_bases(struct commit_list *in);
/* To be used only when object flags after this call no longer matter */
struct commit_list *get_merge_bases_many_dirty(struct commit *one, int n, struct commit **twos);
int is_descendant_of(struct commit *commit, struct commit_list *with_commit);
int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference);
int in_merge_bases(struct commit *commit, struct commit *reference);
/*
* Takes a list of commits and returns a new list where those
* have been removed that can be reached from other commits in
* the list. It is useful for, e.g., reducing the commits
* randomly thrown at the git-merge command and removing
* redundant commits that the user shouldn't have given to it.
*
* This function destroys the STALE bit of the commit objects'
* flags.
*/
struct commit_list *reduce_heads(struct commit_list *heads);
/*
* Like `reduce_heads()`, except it replaces the list. Use this
* instead of `foo = reduce_heads(foo);` to avoid memory leaks.
*/
void reduce_heads_replace(struct commit_list **heads);
int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid);
/*
* Unknown has to be "0" here, because that's the default value for
* contains_cache slab entries that have not yet been assigned.
*/
enum contains_result {
CONTAINS_UNKNOWN = 0,
CONTAINS_NO,
CONTAINS_YES
};
define_commit_slab(contains_cache, enum contains_result);
int commit_contains(struct ref_filter *filter, struct commit *commit,
struct commit_list *list, struct contains_cache *cache);
/*
* Determine if every commit in 'from' can reach at least one commit
* that is marked with 'with_flag'. As we traverse, use 'assign_flag'
* as a marker for commits that are already visited. Do not walk
* commits with date below 'min_commit_date' or generation below
* 'min_generation'.
*/
int can_all_from_reach_with_flag(struct object_array *from,
unsigned int with_flag,
unsigned int assign_flag,
time_t min_commit_date,
uint32_t min_generation);
int can_all_from_reach(struct commit_list *from, struct commit_list *to,
int commit_date_cutoff);
#endif