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git/builtin/rev-list.c
Jeff King 5c9f9bf313 rev-list: "adjust" results of "--count --use-bitmap-index -n" 
If you ask rev-list for:

    git rev-list --count --use-bitmap-index HEAD

we optimize out the actual traversal and just give you the
number of bits set in the commit bitmap. This is faster,
which is good.

But if you ask to limit the size of the traversal, like:

    git rev-list --count --use-bitmap-index -n 100 HEAD

we'll still output the full bitmapped number we found. On
the surface, that might even seem OK. You explicitly asked
to use the bitmap index, and it was cheap to compute the
real answer, so we gave it to you.

But there's something much more complicated going on under
the hood. If we don't have a bitmap directly for HEAD, then
we have to actually traverse backwards, looking for a
bitmapped commit. And _that_ traversal is bounded by our
`-n` count.

This is a good thing, because it bounds the work we have to
do, which is probably what the user wanted by asking for
`-n`. But now it makes the output quite confusing. You might
get many values:

  - your `-n` value, if we walked back and never found a
    bitmap (or fewer if there weren't that many commits)

  - the actual full count, if we found a bitmap root for
    every path of our traversal with in the `-n` limit

  - any number in between! We might have walked back and
    found _some_ bitmaps, but then cut off the traversal
    early with some commits not accounted for in the result.

So you cannot even see a value higher than your `-n` and say
"OK, bitmaps kicked in, this must be the real full count".
The only sane thing is for git to just clamp the value to a
maximum of the `-n` value, which means we should output the
exact same results whether bitmaps are in use or not.

The test in t5310 demonstrates this by using `-n 1`.
Without this patch we fail in the full-bitmap case (where we
do not have to traverse at all) but _not_ in the
partial-bitmap case (where we have to walk down to find an
actual bitmap). With this patch, both cases just work.

I didn't implement the crazy in-between case, just because
it's complicated to set up, and is really a subset of the
full-count case, which we do cover.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-03 09:00:59 -07:00

404 lines
10 KiB
C
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#include "cache.h"
#include "commit.h"
#include "diff.h"
#include "revision.h"
#include "list-objects.h"
#include "pack.h"
#include "pack-bitmap.h"
#include "builtin.h"
#include "log-tree.h"
#include "graph.h"
#include "bisect.h"
static const char rev_list_usage[] =
"git rev-list [OPTION] <commit-id>... [ -- paths... ]\n"
" limiting output:\n"
" --max-count=<n>\n"
" --max-age=<epoch>\n"
" --min-age=<epoch>\n"
" --sparse\n"
" --no-merges\n"
" --min-parents=<n>\n"
" --no-min-parents\n"
" --max-parents=<n>\n"
" --no-max-parents\n"
" --remove-empty\n"
" --all\n"
" --branches\n"
" --tags\n"
" --remotes\n"
" --stdin\n"
" --quiet\n"
" ordering output:\n"
" --topo-order\n"
" --date-order\n"
" --reverse\n"
" formatting output:\n"
" --parents\n"
" --children\n"
" --objects | --objects-edge\n"
" --unpacked\n"
" --header | --pretty\n"
" --abbrev=<n> | --no-abbrev\n"
" --abbrev-commit\n"
" --left-right\n"
" --count\n"
" special purpose:\n"
" --bisect\n"
" --bisect-vars\n"
" --bisect-all"
;
static void finish_commit(struct commit *commit, void *data);
static void show_commit(struct commit *commit, void *data)
{
struct rev_list_info *info = data;
struct rev_info *revs = info->revs;
if (info->flags & REV_LIST_QUIET) {
finish_commit(commit, data);
return;
}
graph_show_commit(revs->graph);
if (revs->count) {
if (commit->object.flags & PATCHSAME)
revs->count_same++;
else if (commit->object.flags & SYMMETRIC_LEFT)
revs->count_left++;
else
revs->count_right++;
finish_commit(commit, data);
return;
}
if (info->show_timestamp)
printf("%lu ", commit->date);
if (info->header_prefix)
fputs(info->header_prefix, stdout);
if (!revs->graph)
fputs(get_revision_mark(revs, commit), stdout);
if (revs->abbrev_commit && revs->abbrev)
fputs(find_unique_abbrev(commit->object.sha1, revs->abbrev),
stdout);
else
fputs(sha1_to_hex(commit->object.sha1), stdout);
if (revs->print_parents) {
struct commit_list *parents = commit->parents;
while (parents) {
printf(" %s", sha1_to_hex(parents->item->object.sha1));
parents = parents->next;
}
}
if (revs->children.name) {
struct commit_list *children;
children = lookup_decoration(&revs->children, &commit->object);
while (children) {
printf(" %s", sha1_to_hex(children->item->object.sha1));
children = children->next;
}
}
show_decorations(revs, commit);
if (revs->commit_format == CMIT_FMT_ONELINE)
putchar(' ');
else
putchar('\n');
if (revs->verbose_header && get_cached_commit_buffer(commit, NULL)) {
struct strbuf buf = STRBUF_INIT;
struct pretty_print_context ctx = {0};
ctx.abbrev = revs->abbrev;
ctx.date_mode = revs->date_mode;
ctx.date_mode_explicit = revs->date_mode_explicit;
ctx.fmt = revs->commit_format;
ctx.output_encoding = get_log_output_encoding();
pretty_print_commit(&ctx, commit, &buf);
if (revs->graph) {
if (buf.len) {
if (revs->commit_format != CMIT_FMT_ONELINE)
graph_show_oneline(revs->graph);
graph_show_commit_msg(revs->graph, &buf);
/*
* Add a newline after the commit message.
*
* Usually, this newline produces a blank
* padding line between entries, in which case
* we need to add graph padding on this line.
*
* However, the commit message may not end in a
* newline. In this case the newline simply
* ends the last line of the commit message,
* and we don't need any graph output. (This
* always happens with CMIT_FMT_ONELINE, and it
* happens with CMIT_FMT_USERFORMAT when the
* format doesn't explicitly end in a newline.)
*/
if (buf.len && buf.buf[buf.len - 1] == '\n')
graph_show_padding(revs->graph);
putchar('\n');
} else {
/*
* If the message buffer is empty, just show
* the rest of the graph output for this
* commit.
*/
if (graph_show_remainder(revs->graph))
putchar('\n');
if (revs->commit_format == CMIT_FMT_ONELINE)
putchar('\n');
}
} else {
if (revs->commit_format != CMIT_FMT_USERFORMAT ||
buf.len) {
fwrite(buf.buf, 1, buf.len, stdout);
putchar(info->hdr_termination);
}
}
strbuf_release(&buf);
} else {
if (graph_show_remainder(revs->graph))
putchar('\n');
}
maybe_flush_or_die(stdout, "stdout");
finish_commit(commit, data);
}
static void finish_commit(struct commit *commit, void *data)
{
if (commit->parents) {
free_commit_list(commit->parents);
commit->parents = NULL;
}
free_commit_buffer(commit);
}
static void finish_object(struct object *obj, const char *name, void *cb_data)
{
struct rev_list_info *info = cb_data;
if (obj->type == OBJ_BLOB && !has_sha1_file(obj->sha1))
die("missing blob object '%s'", sha1_to_hex(obj->sha1));
if (info->revs->verify_objects && !obj->parsed && obj->type != OBJ_COMMIT)
parse_object(obj->sha1);
}
static void show_object(struct object *obj, const char *name, void *cb_data)
{
struct rev_list_info *info = cb_data;
finish_object(obj, name, cb_data);
if (info->flags & REV_LIST_QUIET)
return;
show_object_with_name(stdout, obj, name);
}
static void show_edge(struct commit *commit)
{
printf("-%s\n", sha1_to_hex(commit->object.sha1));
}
static void print_var_str(const char *var, const char *val)
{
printf("%s='%s'\n", var, val);
}
static void print_var_int(const char *var, int val)
{
printf("%s=%d\n", var, val);
}
static int show_bisect_vars(struct rev_list_info *info, int reaches, int all)
{
int cnt, flags = info->flags;
char hex[41] = "";
struct commit_list *tried;
struct rev_info *revs = info->revs;
if (!revs->commits)
return 1;
revs->commits = filter_skipped(revs->commits, &tried,
flags & BISECT_SHOW_ALL,
NULL, NULL);
/*
* revs->commits can reach "reaches" commits among
* "all" commits. If it is good, then there are
* (all-reaches) commits left to be bisected.
* On the other hand, if it is bad, then the set
* to bisect is "reaches".
* A bisect set of size N has (N-1) commits further
* to test, as we already know one bad one.
*/
cnt = all - reaches;
if (cnt < reaches)
cnt = reaches;
if (revs->commits)
strcpy(hex, sha1_to_hex(revs->commits->item->object.sha1));
if (flags & BISECT_SHOW_ALL) {
traverse_commit_list(revs, show_commit, show_object, info);
printf("------\n");
}
print_var_str("bisect_rev", hex);
print_var_int("bisect_nr", cnt - 1);
print_var_int("bisect_good", all - reaches - 1);
print_var_int("bisect_bad", reaches - 1);
print_var_int("bisect_all", all);
print_var_int("bisect_steps", estimate_bisect_steps(all));
return 0;
}
static int show_object_fast(
const unsigned char *sha1,
enum object_type type,
int exclude,
uint32_t name_hash,
struct packed_git *found_pack,
off_t found_offset)
{
fprintf(stdout, "%s\n", sha1_to_hex(sha1));
return 1;
}
int cmd_rev_list(int argc, const char **argv, const char *prefix)
{
struct rev_info revs;
struct rev_list_info info;
int i;
int bisect_list = 0;
int bisect_show_vars = 0;
int bisect_find_all = 0;
int use_bitmap_index = 0;
git_config(git_default_config, NULL);
init_revisions(&revs, prefix);
revs.abbrev = DEFAULT_ABBREV;
revs.commit_format = CMIT_FMT_UNSPECIFIED;
argc = setup_revisions(argc, argv, &revs, NULL);
memset(&info, 0, sizeof(info));
info.revs = &revs;
if (revs.bisect)
bisect_list = 1;
if (DIFF_OPT_TST(&revs.diffopt, QUICK))
info.flags |= REV_LIST_QUIET;
for (i = 1 ; i < argc; i++) {
const char *arg = argv[i];
if (!strcmp(arg, "--header")) {
revs.verbose_header = 1;
continue;
}
if (!strcmp(arg, "--timestamp")) {
info.show_timestamp = 1;
continue;
}
if (!strcmp(arg, "--bisect")) {
bisect_list = 1;
continue;
}
if (!strcmp(arg, "--bisect-all")) {
bisect_list = 1;
bisect_find_all = 1;
info.flags |= BISECT_SHOW_ALL;
revs.show_decorations = 1;
continue;
}
if (!strcmp(arg, "--bisect-vars")) {
bisect_list = 1;
bisect_show_vars = 1;
continue;
}
if (!strcmp(arg, "--use-bitmap-index")) {
use_bitmap_index = 1;
continue;
}
if (!strcmp(arg, "--test-bitmap")) {
test_bitmap_walk(&revs);
return 0;
}
usage(rev_list_usage);
}
if (revs.commit_format != CMIT_FMT_UNSPECIFIED) {
/* The command line has a --pretty */
info.hdr_termination = '\n';
if (revs.commit_format == CMIT_FMT_ONELINE)
info.header_prefix = "";
else
info.header_prefix = "commit ";
}
else if (revs.verbose_header)
/* Only --header was specified */
revs.commit_format = CMIT_FMT_RAW;
if ((!revs.commits &&
(!(revs.tag_objects || revs.tree_objects || revs.blob_objects) &&
!revs.pending.nr)) ||
revs.diff)
usage(rev_list_usage);
save_commit_buffer = (revs.verbose_header ||
revs.grep_filter.pattern_list ||
revs.grep_filter.header_list);
if (bisect_list)
revs.limited = 1;
if (use_bitmap_index && !revs.prune) {
if (revs.count && !revs.left_right && !revs.cherry_mark) {
uint32_t commit_count;
int max_count = revs.max_count;
if (!prepare_bitmap_walk(&revs)) {
count_bitmap_commit_list(&commit_count, NULL, NULL, NULL);
if (max_count >= 0 && max_count < commit_count)
commit_count = max_count;
printf("%d\n", commit_count);
return 0;
}
} else if (revs.tag_objects && revs.tree_objects && revs.blob_objects) {
if (!prepare_bitmap_walk(&revs)) {
traverse_bitmap_commit_list(&show_object_fast);
return 0;
}
}
}
if (prepare_revision_walk(&revs))
die("revision walk setup failed");
if (revs.tree_objects)
mark_edges_uninteresting(&revs, show_edge);
if (bisect_list) {
int reaches = reaches, all = all;
revs.commits = find_bisection(revs.commits, &reaches, &all,
bisect_find_all);
if (bisect_show_vars)
return show_bisect_vars(&info, reaches, all);
}
traverse_commit_list(&revs, show_commit, show_object, &info);
if (revs.count) {
if (revs.left_right && revs.cherry_mark)
printf("%d\t%d\t%d\n", revs.count_left, revs.count_right, revs.count_same);
else if (revs.left_right)
printf("%d\t%d\n", revs.count_left, revs.count_right);
else if (revs.cherry_mark)
printf("%d\t%d\n", revs.count_left + revs.count_right, revs.count_same);
else
printf("%d\n", revs.count_left + revs.count_right);
}
return 0;
}
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