Commit d9c66f0b authored by Johannes Schindelin's avatar Johannes Schindelin Committed by Junio C Hamano

range-diff: first rudimentary implementation

At this stage, `git range-diff` can determine corresponding commits
of two related commit ranges. This makes use of the recently introduced
implementation of the linear assignment algorithm.

The core of this patch is a straight port of the ideas of tbdiff, the
apparently dormant project at https://github.com/trast/tbdiff.

The output does not at all match `tbdiff`'s output yet, as this patch
really concentrates on getting the patch matching part right.

Note: due to differences in the diff algorithm (`tbdiff` uses the Python
module `difflib`, Git uses its xdiff fork), the cost matrix calculated
by `range-diff` is different (but very similar) to the one calculated
by `tbdiff`. Therefore, it is possible that they find different matching
commits in corner cases (e.g. when a patch was split into two patches of
roughly equal length).
Signed-off-by: Johannes Schindelin's avatarJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: default avatarJunio C Hamano <gitster@pobox.com>
parent 348ae56c
......@@ -925,6 +925,7 @@ LIB_OBJS += progress.o
LIB_OBJS += prompt.o
LIB_OBJS += protocol.o
LIB_OBJS += quote.o
LIB_OBJS += range-diff.o
LIB_OBJS += reachable.o
LIB_OBJS += read-cache.o
LIB_OBJS += reflog-walk.o
......
#include "cache.h"
#include "builtin.h"
#include "parse-options.h"
#include "range-diff.h"
static const char * const builtin_range_diff_usage[] = {
N_("git range-diff [<options>] <old-base>..<old-tip> <new-base>..<new-tip>"),
......@@ -17,9 +18,51 @@ int cmd_range_diff(int argc, const char **argv, const char *prefix)
N_("Percentage by which creation is weighted")),
OPT_END()
};
int res = 0;
struct strbuf range1 = STRBUF_INIT, range2 = STRBUF_INIT;
argc = parse_options(argc, argv, NULL, options,
builtin_range_diff_usage, 0);
return 0;
if (argc == 2) {
if (!strstr(argv[0], ".."))
die(_("no .. in range: '%s'"), argv[0]);
strbuf_addstr(&range1, argv[0]);
if (!strstr(argv[1], ".."))
die(_("no .. in range: '%s'"), argv[1]);
strbuf_addstr(&range2, argv[1]);
} else if (argc == 3) {
strbuf_addf(&range1, "%s..%s", argv[0], argv[1]);
strbuf_addf(&range2, "%s..%s", argv[0], argv[2]);
} else if (argc == 1) {
const char *b = strstr(argv[0], "..."), *a = argv[0];
int a_len;
if (!b) {
error(_("single arg format must be symmetric range"));
usage_with_options(builtin_range_diff_usage, options);
}
a_len = (int)(b - a);
if (!a_len) {
a = "HEAD";
a_len = strlen(a);
}
b += 3;
if (!*b)
b = "HEAD";
strbuf_addf(&range1, "%s..%.*s", b, a_len, a);
strbuf_addf(&range2, "%.*s..%s", a_len, a, b);
} else {
error(_("need two commit ranges"));
usage_with_options(builtin_range_diff_usage, options);
}
res = show_range_diff(range1.buf, range2.buf, creation_factor);
strbuf_release(&range1);
strbuf_release(&range2);
return res;
}
#include "cache.h"
#include "range-diff.h"
#include "string-list.h"
#include "run-command.h"
#include "argv-array.h"
#include "hashmap.h"
#include "xdiff-interface.h"
#include "linear-assignment.h"
struct patch_util {
/* For the search for an exact match */
struct hashmap_entry e;
const char *diff, *patch;
int i;
int diffsize;
size_t diff_offset;
/* the index of the matching item in the other branch, or -1 */
int matching;
struct object_id oid;
};
/*
* Reads the patches into a string list, with the `util` field being populated
* as struct object_id (will need to be free()d).
*/
static int read_patches(const char *range, struct string_list *list)
{
struct child_process cp = CHILD_PROCESS_INIT;
FILE *in;
struct strbuf buf = STRBUF_INIT, line = STRBUF_INIT;
struct patch_util *util = NULL;
int in_header = 1;
argv_array_pushl(&cp.args, "log", "--no-color", "-p", "--no-merges",
"--reverse", "--date-order", "--decorate=no",
"--no-abbrev-commit", range,
NULL);
cp.out = -1;
cp.no_stdin = 1;
cp.git_cmd = 1;
if (start_command(&cp))
return error_errno(_("could not start `log`"));
in = fdopen(cp.out, "r");
if (!in) {
error_errno(_("could not read `log` output"));
finish_command(&cp);
return -1;
}
while (strbuf_getline(&line, in) != EOF) {
const char *p;
if (skip_prefix(line.buf, "commit ", &p)) {
if (util) {
string_list_append(list, buf.buf)->util = util;
strbuf_reset(&buf);
}
util = xcalloc(sizeof(*util), 1);
if (get_oid(p, &util->oid)) {
error(_("could not parse commit '%s'"), p);
free(util);
string_list_clear(list, 1);
strbuf_release(&buf);
strbuf_release(&line);
fclose(in);
finish_command(&cp);
return -1;
}
util->matching = -1;
in_header = 1;
continue;
}
if (starts_with(line.buf, "diff --git")) {
in_header = 0;
strbuf_addch(&buf, '\n');
if (!util->diff_offset)
util->diff_offset = buf.len;
strbuf_addbuf(&buf, &line);
} else if (in_header) {
if (starts_with(line.buf, "Author: ")) {
strbuf_addbuf(&buf, &line);
strbuf_addstr(&buf, "\n\n");
} else if (starts_with(line.buf, " ")) {
strbuf_addbuf(&buf, &line);
strbuf_addch(&buf, '\n');
}
continue;
} else if (starts_with(line.buf, "@@ "))
strbuf_addstr(&buf, "@@");
else if (!line.buf[0] || starts_with(line.buf, "index "))
/*
* A completely blank (not ' \n', which is context)
* line is not valid in a diff. We skip it
* silently, because this neatly handles the blank
* separator line between commits in git-log
* output.
*
* We also want to ignore the diff's `index` lines
* because they contain exact blob hashes in which
* we are not interested.
*/
continue;
else
strbuf_addbuf(&buf, &line);
strbuf_addch(&buf, '\n');
util->diffsize++;
}
fclose(in);
strbuf_release(&line);
if (util)
string_list_append(list, buf.buf)->util = util;
strbuf_release(&buf);
if (finish_command(&cp))
return -1;
return 0;
}
static int patch_util_cmp(const void *dummy, const struct patch_util *a,
const struct patch_util *b, const char *keydata)
{
return strcmp(a->diff, keydata ? keydata : b->diff);
}
static void find_exact_matches(struct string_list *a, struct string_list *b)
{
struct hashmap map;
int i;
hashmap_init(&map, (hashmap_cmp_fn)patch_util_cmp, NULL, 0);
/* First, add the patches of a to a hash map */
for (i = 0; i < a->nr; i++) {
struct patch_util *util = a->items[i].util;
util->i = i;
util->patch = a->items[i].string;
util->diff = util->patch + util->diff_offset;
hashmap_entry_init(util, strhash(util->diff));
hashmap_add(&map, util);
}
/* Now try to find exact matches in b */
for (i = 0; i < b->nr; i++) {
struct patch_util *util = b->items[i].util, *other;
util->i = i;
util->patch = b->items[i].string;
util->diff = util->patch + util->diff_offset;
hashmap_entry_init(util, strhash(util->diff));
other = hashmap_remove(&map, util, NULL);
if (other) {
if (other->matching >= 0)
BUG("already assigned!");
other->matching = i;
util->matching = other->i;
}
}
hashmap_free(&map, 0);
}
static void diffsize_consume(void *data, char *line, unsigned long len)
{
(*(int *)data)++;
}
static int diffsize(const char *a, const char *b)
{
xpparam_t pp = { 0 };
xdemitconf_t cfg = { 0 };
mmfile_t mf1, mf2;
int count = 0;
mf1.ptr = (char *)a;
mf1.size = strlen(a);
mf2.ptr = (char *)b;
mf2.size = strlen(b);
cfg.ctxlen = 3;
if (!xdi_diff_outf(&mf1, &mf2, diffsize_consume, &count, &pp, &cfg))
return count;
error(_("failed to generate diff"));
return COST_MAX;
}
static void get_correspondences(struct string_list *a, struct string_list *b,
int creation_factor)
{
int n = a->nr + b->nr;
int *cost, c, *a2b, *b2a;
int i, j;
ALLOC_ARRAY(cost, st_mult(n, n));
ALLOC_ARRAY(a2b, n);
ALLOC_ARRAY(b2a, n);
for (i = 0; i < a->nr; i++) {
struct patch_util *a_util = a->items[i].util;
for (j = 0; j < b->nr; j++) {
struct patch_util *b_util = b->items[j].util;
if (a_util->matching == j)
c = 0;
else if (a_util->matching < 0 && b_util->matching < 0)
c = diffsize(a_util->diff, b_util->diff);
else
c = COST_MAX;
cost[i + n * j] = c;
}
c = a_util->matching < 0 ?
a_util->diffsize * creation_factor / 100 : COST_MAX;
for (j = b->nr; j < n; j++)
cost[i + n * j] = c;
}
for (j = 0; j < b->nr; j++) {
struct patch_util *util = b->items[j].util;
c = util->matching < 0 ?
util->diffsize * creation_factor / 100 : COST_MAX;
for (i = a->nr; i < n; i++)
cost[i + n * j] = c;
}
for (i = a->nr; i < n; i++)
for (j = b->nr; j < n; j++)
cost[i + n * j] = 0;
compute_assignment(n, n, cost, a2b, b2a);
for (i = 0; i < a->nr; i++)
if (a2b[i] >= 0 && a2b[i] < b->nr) {
struct patch_util *a_util = a->items[i].util;
struct patch_util *b_util = b->items[a2b[i]].util;
a_util->matching = a2b[i];
b_util->matching = i;
}
free(cost);
free(a2b);
free(b2a);
}
static const char *short_oid(struct patch_util *util)
{
return find_unique_abbrev(&util->oid, DEFAULT_ABBREV);
}
static void output(struct string_list *a, struct string_list *b)
{
int i;
for (i = 0; i < b->nr; i++) {
struct patch_util *util = b->items[i].util, *prev;
if (util->matching < 0)
printf("-: -------- > %d: %s\n",
i + 1, short_oid(util));
else {
prev = a->items[util->matching].util;
printf("%d: %s ! %d: %s\n",
util->matching + 1, short_oid(prev),
i + 1, short_oid(util));
}
}
for (i = 0; i < a->nr; i++) {
struct patch_util *util = a->items[i].util;
if (util->matching < 0)
printf("%d: %s < -: --------\n",
i + 1, short_oid(util));
}
}
int show_range_diff(const char *range1, const char *range2,
int creation_factor)
{
int res = 0;
struct string_list branch1 = STRING_LIST_INIT_DUP;
struct string_list branch2 = STRING_LIST_INIT_DUP;
if (read_patches(range1, &branch1))
res = error(_("could not parse log for '%s'"), range1);
if (!res && read_patches(range2, &branch2))
res = error(_("could not parse log for '%s'"), range2);
if (!res) {
find_exact_matches(&branch1, &branch2);
get_correspondences(&branch1, &branch2, creation_factor);
output(&branch1, &branch2);
}
string_list_clear(&branch1, 1);
string_list_clear(&branch2, 1);
return res;
}
#ifndef RANGE_DIFF_H
#define RANGE_DIFF_H
int show_range_diff(const char *range1, const char *range2,
int creation_factor);
#endif
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