git-commit-vandalism/wt-status.c
Linus Torvalds d1f2d7e8ca Make run_diff_index() use unpack_trees(), not read_tree()
A plain "git commit" would still run lstat() a lot more than necessary,
because wt_status_print() would cause the index to be repeatedly flushed
and re-read by wt_read_cache(), and that would cause the CE_UPTODATE bit
to be lost, resulting in the files in the index being lstat'ed three
times each.

The reason why wt-status.c ended up invalidating and re-reading the
cache multiple times was that it uses "run_diff_index()", which in turn
uses "read_tree()" to populate the index with *both* the old index and
the tree we want to compare against.

So this patch re-writes run_diff_index() to not use read_tree(), but
instead use "unpack_trees()" to diff the index to a tree.  That, in
turn, means that we don't need to modify the index itself, which then
means that we don't need to invalidate it and re-read it!

This, together with the lstat() optimizations, means that "git commit"
on the kernel tree really only needs to lstat() the index entries once.
That noticeably cuts down on the cached timings.

Best time before:

	[torvalds@woody linux]$ time git commit > /dev/null
	real    0m0.399s
	user    0m0.232s
	sys     0m0.164s

Best time after:

	[torvalds@woody linux]$ time git commit > /dev/null
	real    0m0.254s
	user    0m0.140s
	sys     0m0.112s

so it's a noticeable improvement in addition to being a nice conceptual
cleanup (it's really not that pretty that "run_diff_index()" dirties the
index!)

Doing an "strace -c" on it also shows that as it cuts the number of
lstat() calls by two thirds, it goes from being lstat()-limited to being
limited by getdents() (which is the readdir system call):

Before:
	% time     seconds  usecs/call     calls    errors syscall
	------ ----------- ----------- --------- --------- ----------------
	 60.69    0.000704           0     69230        31 lstat
	 23.62    0.000274           0      5522           getdents
	  8.36    0.000097           0      5508      2638 open
	  2.59    0.000030           0      2869           close
	  2.50    0.000029           0       274           write
	  1.47    0.000017           0      2844           fstat

After:
	% time     seconds  usecs/call     calls    errors syscall
	------ ----------- ----------- --------- --------- ----------------
	 45.17    0.000276           0      5522           getdents
	 26.51    0.000162           0     23112        31 lstat
	 19.80    0.000121           0      5503      2638 open
	  4.91    0.000030           0      2864           close
	  1.48    0.000020           0       274           write
	  1.34    0.000018           0      2844           fstat
	...

It passes the test-suite for me, but this is another of one of those
really core functions, and certainly pretty subtle, so..

NOTE! The Linux lstat() system call is really quite cheap when everything
is cached, so the fact that this is quite noticeable on Linux is likely to
mean that it is *much* more noticeable on other operating systems. I bet
you'll see a much bigger performance improvement from this on Windows in
particular.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-01-21 13:05:27 -08:00

404 lines
10 KiB
C

#include "cache.h"
#include "wt-status.h"
#include "color.h"
#include "object.h"
#include "dir.h"
#include "commit.h"
#include "diff.h"
#include "revision.h"
#include "diffcore.h"
int wt_status_relative_paths = 1;
int wt_status_use_color = 0;
static char wt_status_colors[][COLOR_MAXLEN] = {
"", /* WT_STATUS_HEADER: normal */
"\033[32m", /* WT_STATUS_UPDATED: green */
"\033[31m", /* WT_STATUS_CHANGED: red */
"\033[31m", /* WT_STATUS_UNTRACKED: red */
};
static const char use_add_msg[] =
"use \"git add <file>...\" to update what will be committed";
static const char use_add_rm_msg[] =
"use \"git add/rm <file>...\" to update what will be committed";
static const char use_add_to_include_msg[] =
"use \"git add <file>...\" to include in what will be committed";
static int parse_status_slot(const char *var, int offset)
{
if (!strcasecmp(var+offset, "header"))
return WT_STATUS_HEADER;
if (!strcasecmp(var+offset, "updated")
|| !strcasecmp(var+offset, "added"))
return WT_STATUS_UPDATED;
if (!strcasecmp(var+offset, "changed"))
return WT_STATUS_CHANGED;
if (!strcasecmp(var+offset, "untracked"))
return WT_STATUS_UNTRACKED;
die("bad config variable '%s'", var);
}
static const char* color(int slot)
{
return wt_status_use_color ? wt_status_colors[slot] : "";
}
void wt_status_prepare(struct wt_status *s)
{
unsigned char sha1[20];
const char *head;
memset(s, 0, sizeof(*s));
head = resolve_ref("HEAD", sha1, 0, NULL);
s->branch = head ? xstrdup(head) : NULL;
s->reference = "HEAD";
s->fp = stdout;
s->index_file = get_index_file();
}
static void wt_status_print_cached_header(struct wt_status *s)
{
const char *c = color(WT_STATUS_HEADER);
color_fprintf_ln(s->fp, c, "# Changes to be committed:");
if (s->reference) {
color_fprintf_ln(s->fp, c, "# (use \"git reset %s <file>...\" to unstage)", s->reference);
} else {
color_fprintf_ln(s->fp, c, "# (use \"git rm --cached <file>...\" to unstage)");
}
color_fprintf_ln(s->fp, c, "#");
}
static void wt_status_print_header(struct wt_status *s,
const char *main, const char *sub)
{
const char *c = color(WT_STATUS_HEADER);
color_fprintf_ln(s->fp, c, "# %s:", main);
color_fprintf_ln(s->fp, c, "# (%s)", sub);
color_fprintf_ln(s->fp, c, "#");
}
static void wt_status_print_trailer(struct wt_status *s)
{
color_fprintf_ln(s->fp, color(WT_STATUS_HEADER), "#");
}
static char *quote_path(const char *in, int len,
struct strbuf *out, const char *prefix)
{
if (len < 0)
len = strlen(in);
strbuf_grow(out, len);
strbuf_setlen(out, 0);
if (prefix) {
int off = 0;
while (prefix[off] && off < len && prefix[off] == in[off])
if (prefix[off] == '/') {
prefix += off + 1;
in += off + 1;
len -= off + 1;
off = 0;
} else
off++;
for (; *prefix; prefix++)
if (*prefix == '/')
strbuf_addstr(out, "../");
}
for ( ; len > 0; in++, len--) {
int ch = *in;
switch (ch) {
case '\n':
strbuf_addstr(out, "\\n");
break;
case '\r':
strbuf_addstr(out, "\\r");
break;
default:
strbuf_addch(out, ch);
continue;
}
}
if (!out->len)
strbuf_addstr(out, "./");
return out->buf;
}
static void wt_status_print_filepair(struct wt_status *s,
int t, struct diff_filepair *p)
{
const char *c = color(t);
const char *one, *two;
struct strbuf onebuf, twobuf;
strbuf_init(&onebuf, 0);
strbuf_init(&twobuf, 0);
one = quote_path(p->one->path, -1, &onebuf, s->prefix);
two = quote_path(p->two->path, -1, &twobuf, s->prefix);
color_fprintf(s->fp, color(WT_STATUS_HEADER), "#\t");
switch (p->status) {
case DIFF_STATUS_ADDED:
color_fprintf(s->fp, c, "new file: %s", one);
break;
case DIFF_STATUS_COPIED:
color_fprintf(s->fp, c, "copied: %s -> %s", one, two);
break;
case DIFF_STATUS_DELETED:
color_fprintf(s->fp, c, "deleted: %s", one);
break;
case DIFF_STATUS_MODIFIED:
color_fprintf(s->fp, c, "modified: %s", one);
break;
case DIFF_STATUS_RENAMED:
color_fprintf(s->fp, c, "renamed: %s -> %s", one, two);
break;
case DIFF_STATUS_TYPE_CHANGED:
color_fprintf(s->fp, c, "typechange: %s", one);
break;
case DIFF_STATUS_UNKNOWN:
color_fprintf(s->fp, c, "unknown: %s", one);
break;
case DIFF_STATUS_UNMERGED:
color_fprintf(s->fp, c, "unmerged: %s", one);
break;
default:
die("bug: unhandled diff status %c", p->status);
}
fprintf(s->fp, "\n");
strbuf_release(&onebuf);
strbuf_release(&twobuf);
}
static void wt_status_print_updated_cb(struct diff_queue_struct *q,
struct diff_options *options,
void *data)
{
struct wt_status *s = data;
int shown_header = 0;
int i;
for (i = 0; i < q->nr; i++) {
if (q->queue[i]->status == 'U')
continue;
if (!shown_header) {
wt_status_print_cached_header(s);
s->commitable = 1;
shown_header = 1;
}
wt_status_print_filepair(s, WT_STATUS_UPDATED, q->queue[i]);
}
if (shown_header)
wt_status_print_trailer(s);
}
static void wt_status_print_changed_cb(struct diff_queue_struct *q,
struct diff_options *options,
void *data)
{
struct wt_status *s = data;
int i;
if (q->nr) {
const char *msg = use_add_msg;
s->workdir_dirty = 1;
for (i = 0; i < q->nr; i++)
if (q->queue[i]->status == DIFF_STATUS_DELETED) {
msg = use_add_rm_msg;
break;
}
wt_status_print_header(s, "Changed but not updated", msg);
}
for (i = 0; i < q->nr; i++)
wt_status_print_filepair(s, WT_STATUS_CHANGED, q->queue[i]);
if (q->nr)
wt_status_print_trailer(s);
}
static void wt_status_print_initial(struct wt_status *s)
{
int i;
struct strbuf buf;
strbuf_init(&buf, 0);
if (active_nr) {
s->commitable = 1;
wt_status_print_cached_header(s);
}
for (i = 0; i < active_nr; i++) {
color_fprintf(s->fp, color(WT_STATUS_HEADER), "#\t");
color_fprintf_ln(s->fp, color(WT_STATUS_UPDATED), "new file: %s",
quote_path(active_cache[i]->name, -1,
&buf, s->prefix));
}
if (active_nr)
wt_status_print_trailer(s);
strbuf_release(&buf);
}
static void wt_status_print_updated(struct wt_status *s)
{
struct rev_info rev;
init_revisions(&rev, NULL);
setup_revisions(0, NULL, &rev, s->reference);
rev.diffopt.output_format |= DIFF_FORMAT_CALLBACK;
rev.diffopt.format_callback = wt_status_print_updated_cb;
rev.diffopt.format_callback_data = s;
rev.diffopt.detect_rename = 1;
rev.diffopt.rename_limit = 100;
rev.diffopt.break_opt = 0;
run_diff_index(&rev, 1);
}
static void wt_status_print_changed(struct wt_status *s)
{
struct rev_info rev;
init_revisions(&rev, "");
setup_revisions(0, NULL, &rev, NULL);
rev.diffopt.output_format |= DIFF_FORMAT_CALLBACK;
rev.diffopt.format_callback = wt_status_print_changed_cb;
rev.diffopt.format_callback_data = s;
run_diff_files(&rev, 0);
}
static void wt_status_print_untracked(struct wt_status *s)
{
struct dir_struct dir;
int i;
int shown_header = 0;
struct strbuf buf;
strbuf_init(&buf, 0);
memset(&dir, 0, sizeof(dir));
if (!s->untracked) {
dir.show_other_directories = 1;
dir.hide_empty_directories = 1;
}
setup_standard_excludes(&dir);
read_directory(&dir, ".", "", 0, NULL);
for(i = 0; i < dir.nr; i++) {
/* check for matching entry, which is unmerged; lifted from
* builtin-ls-files:show_other_files */
struct dir_entry *ent = dir.entries[i];
int pos = cache_name_pos(ent->name, ent->len);
struct cache_entry *ce;
if (0 <= pos)
die("bug in wt_status_print_untracked");
pos = -pos - 1;
if (pos < active_nr) {
ce = active_cache[pos];
if (ce_namelen(ce) == ent->len &&
!memcmp(ce->name, ent->name, ent->len))
continue;
}
if (!shown_header) {
s->workdir_untracked = 1;
wt_status_print_header(s, "Untracked files",
use_add_to_include_msg);
shown_header = 1;
}
color_fprintf(s->fp, color(WT_STATUS_HEADER), "#\t");
color_fprintf_ln(s->fp, color(WT_STATUS_UNTRACKED), "%s",
quote_path(ent->name, ent->len,
&buf, s->prefix));
}
strbuf_release(&buf);
}
static void wt_status_print_verbose(struct wt_status *s)
{
struct rev_info rev;
int saved_stdout;
fflush(s->fp);
/* Sigh, the entire diff machinery is hardcoded to output to
* stdout. Do the dup-dance...*/
saved_stdout = dup(STDOUT_FILENO);
if (saved_stdout < 0 ||dup2(fileno(s->fp), STDOUT_FILENO) < 0)
die("couldn't redirect stdout\n");
init_revisions(&rev, NULL);
setup_revisions(0, NULL, &rev, s->reference);
rev.diffopt.output_format |= DIFF_FORMAT_PATCH;
rev.diffopt.detect_rename = 1;
run_diff_index(&rev, 1);
fflush(stdout);
if (dup2(saved_stdout, STDOUT_FILENO) < 0)
die("couldn't restore stdout\n");
close(saved_stdout);
}
void wt_status_print(struct wt_status *s)
{
unsigned char sha1[20];
s->is_initial = get_sha1(s->reference, sha1) ? 1 : 0;
if (s->branch) {
const char *on_what = "On branch ";
const char *branch_name = s->branch;
if (!prefixcmp(branch_name, "refs/heads/"))
branch_name += 11;
else if (!strcmp(branch_name, "HEAD")) {
branch_name = "";
on_what = "Not currently on any branch.";
}
color_fprintf_ln(s->fp, color(WT_STATUS_HEADER),
"# %s%s", on_what, branch_name);
}
if (s->is_initial) {
color_fprintf_ln(s->fp, color(WT_STATUS_HEADER), "#");
color_fprintf_ln(s->fp, color(WT_STATUS_HEADER), "# Initial commit");
color_fprintf_ln(s->fp, color(WT_STATUS_HEADER), "#");
wt_status_print_initial(s);
}
else {
wt_status_print_updated(s);
}
wt_status_print_changed(s);
wt_status_print_untracked(s);
if (s->verbose && !s->is_initial)
wt_status_print_verbose(s);
if (!s->commitable) {
if (s->amend)
fprintf(s->fp, "# No changes\n");
else if (s->nowarn)
; /* nothing */
else if (s->workdir_dirty)
printf("no changes added to commit (use \"git add\" and/or \"git commit -a\")\n");
else if (s->workdir_untracked)
printf("nothing added to commit but untracked files present (use \"git add\" to track)\n");
else if (s->is_initial)
printf("nothing to commit (create/copy files and use \"git add\" to track)\n");
else
printf("nothing to commit (working directory clean)\n");
}
}
int git_status_config(const char *k, const char *v)
{
if (!strcmp(k, "status.color") || !strcmp(k, "color.status")) {
wt_status_use_color = git_config_colorbool(k, v, -1);
return 0;
}
if (!prefixcmp(k, "status.color.") || !prefixcmp(k, "color.status.")) {
int slot = parse_status_slot(k, 13);
color_parse(v, k, wt_status_colors[slot]);
return 0;
}
if (!strcmp(k, "status.relativepaths")) {
wt_status_relative_paths = git_config_bool(k, v);
return 0;
}
return git_default_config(k, v);
}