git/tree-diff.c
Jeff King dd98d88be7 use custom rename score during --follow
If you provide a custom rename score on the command line,
like:

  git log -M50 --follow foo.c

it is completely ignored, and there is no way to --follow
with a looser rename score. Instead, let's use the same
rename score that will be used for generating diffs. This is
convenient, and mirrors what we do with the break-score.

You can see an example of it being useful in git.git:

  $ git log --oneline --summary --follow \
	    Documentation/technical/api-string-list.txt
  86d4b52 string-list: Add API to remove an item from an unsorted list
  1d2f80f string_list: Fix argument order for string_list_append
  e242148 string-list: add unsorted_string_list_lookup()
  0dda1d1 Fix two leftovers from path_list->string_list
  c455c87 Rename path_list to string_list
   create mode 100644 Documentation/technical/api-string-list.txt

  $ git log --oneline --summary -M40 --follow \
	  Documentation/technical/api-string-list.txt
  86d4b52 string-list: Add API to remove an item from an unsorted list
  1d2f80f string_list: Fix argument order for string_list_append
  e242148 string-list: add unsorted_string_list_lookup()
  0dda1d1 Fix two leftovers from path_list->string_list
  c455c87 Rename path_list to string_list
   rename Documentation/technical/{api-path-list.txt => api-string-list.txt} (47%)
  328a475 path-list documentation: document all functions and data structures
  530e741 Start preparing the API documents.
   create mode 100644 Documentation/technical/api-path-list.txt

You could have two separate rename scores, one for following
and one for diff. But almost nobody is going to want that,
and it would just be unnecessarily confusing. Besides which,
we re-use the diff results from try_to_follow_renames for
the actual diff output, which means having them as separate
scores is actively wrong. E.g., with the current code, you
get:

  $ git log --oneline --diff-filter=R --name-status \
            -M90 --follow git.spec.in
  27dedf0 GIT 0.99.9j aka 1.0rc3
  R084    git-core.spec.in        git.spec.in
  f85639c Rename the RPM from "git" to "git-core"
  R098    git.spec.in     git-core.spec.in

The first one should not be considered a rename by the -M
score we gave, but we print it anyway, since we blindly
re-use the diff information from the follow (which uses the
default score). So this could also be considered simply a
bug-fix, as with the current code "-M" is completely ignored
when using "--follow".

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-12-16 12:33:49 -08:00

324 lines
8.6 KiB
C

/*
* Helper functions for tree diff generation
*/
#include "cache.h"
#include "diff.h"
#include "diffcore.h"
#include "tree.h"
static void show_entry(struct diff_options *opt, const char *prefix,
struct tree_desc *desc, struct strbuf *base);
static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2,
struct strbuf *base, struct diff_options *opt)
{
unsigned mode1, mode2;
const char *path1, *path2;
const unsigned char *sha1, *sha2;
int cmp, pathlen1, pathlen2;
int old_baselen = base->len;
sha1 = tree_entry_extract(t1, &path1, &mode1);
sha2 = tree_entry_extract(t2, &path2, &mode2);
pathlen1 = tree_entry_len(&t1->entry);
pathlen2 = tree_entry_len(&t2->entry);
cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
if (cmp < 0) {
show_entry(opt, "-", t1, base);
return -1;
}
if (cmp > 0) {
show_entry(opt, "+", t2, base);
return 1;
}
if (!DIFF_OPT_TST(opt, FIND_COPIES_HARDER) && !hashcmp(sha1, sha2) && mode1 == mode2)
return 0;
/*
* If the filemode has changed to/from a directory from/to a regular
* file, we need to consider it a remove and an add.
*/
if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
show_entry(opt, "-", t1, base);
show_entry(opt, "+", t2, base);
return 0;
}
strbuf_add(base, path1, pathlen1);
if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode1)) {
if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE)) {
opt->change(opt, mode1, mode2,
sha1, sha2, base->buf, 0, 0);
}
strbuf_addch(base, '/');
diff_tree_sha1(sha1, sha2, base->buf, opt);
} else {
opt->change(opt, mode1, mode2, sha1, sha2, base->buf, 0, 0);
}
strbuf_setlen(base, old_baselen);
return 0;
}
/* A whole sub-tree went away or appeared */
static void show_tree(struct diff_options *opt, const char *prefix,
struct tree_desc *desc, struct strbuf *base)
{
enum interesting match = entry_not_interesting;
for (; desc->size; update_tree_entry(desc)) {
if (match != all_entries_interesting) {
match = tree_entry_interesting(&desc->entry, base, 0,
&opt->pathspec);
if (match == all_entries_not_interesting)
break;
if (match == entry_not_interesting)
continue;
}
show_entry(opt, prefix, desc, base);
}
}
/* A file entry went away or appeared */
static void show_entry(struct diff_options *opt, const char *prefix,
struct tree_desc *desc, struct strbuf *base)
{
unsigned mode;
const char *path;
const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
int pathlen = tree_entry_len(&desc->entry);
int old_baselen = base->len;
strbuf_add(base, path, pathlen);
if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode)) {
enum object_type type;
struct tree_desc inner;
void *tree;
unsigned long size;
tree = read_sha1_file(sha1, &type, &size);
if (!tree || type != OBJ_TREE)
die("corrupt tree sha %s", sha1_to_hex(sha1));
if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE))
opt->add_remove(opt, *prefix, mode, sha1, base->buf, 0);
strbuf_addch(base, '/');
init_tree_desc(&inner, tree, size);
show_tree(opt, prefix, &inner, base);
free(tree);
} else
opt->add_remove(opt, prefix[0], mode, sha1, base->buf, 0);
strbuf_setlen(base, old_baselen);
}
static void skip_uninteresting(struct tree_desc *t, struct strbuf *base,
struct diff_options *opt,
enum interesting *match)
{
while (t->size) {
*match = tree_entry_interesting(&t->entry, base, 0, &opt->pathspec);
if (*match) {
if (*match == all_entries_not_interesting)
t->size = 0;
break;
}
update_tree_entry(t);
}
}
int diff_tree(struct tree_desc *t1, struct tree_desc *t2,
const char *base_str, struct diff_options *opt)
{
struct strbuf base;
int baselen = strlen(base_str);
enum interesting t1_match = entry_not_interesting;
enum interesting t2_match = entry_not_interesting;
/* Enable recursion indefinitely */
opt->pathspec.recursive = DIFF_OPT_TST(opt, RECURSIVE);
opt->pathspec.max_depth = -1;
strbuf_init(&base, PATH_MAX);
strbuf_add(&base, base_str, baselen);
for (;;) {
if (diff_can_quit_early(opt))
break;
if (opt->pathspec.nr) {
skip_uninteresting(t1, &base, opt, &t1_match);
skip_uninteresting(t2, &base, opt, &t2_match);
}
if (!t1->size) {
if (!t2->size)
break;
show_entry(opt, "+", t2, &base);
update_tree_entry(t2);
continue;
}
if (!t2->size) {
show_entry(opt, "-", t1, &base);
update_tree_entry(t1);
continue;
}
switch (compare_tree_entry(t1, t2, &base, opt)) {
case -1:
update_tree_entry(t1);
continue;
case 0:
update_tree_entry(t1);
/* Fallthrough */
case 1:
update_tree_entry(t2);
continue;
}
die("git diff-tree: internal error");
}
strbuf_release(&base);
return 0;
}
/*
* Does it look like the resulting diff might be due to a rename?
* - single entry
* - not a valid previous file
*/
static inline int diff_might_be_rename(void)
{
return diff_queued_diff.nr == 1 &&
!DIFF_FILE_VALID(diff_queued_diff.queue[0]->one);
}
static void try_to_follow_renames(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
{
struct diff_options diff_opts;
struct diff_queue_struct *q = &diff_queued_diff;
struct diff_filepair *choice;
const char *paths[1];
int i;
/* Remove the file creation entry from the diff queue, and remember it */
choice = q->queue[0];
q->nr = 0;
diff_setup(&diff_opts);
DIFF_OPT_SET(&diff_opts, RECURSIVE);
DIFF_OPT_SET(&diff_opts, FIND_COPIES_HARDER);
diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
diff_opts.single_follow = opt->pathspec.raw[0];
diff_opts.break_opt = opt->break_opt;
diff_opts.rename_score = opt->rename_score;
paths[0] = NULL;
diff_tree_setup_paths(paths, &diff_opts);
if (diff_setup_done(&diff_opts) < 0)
die("unable to set up diff options to follow renames");
diff_tree(t1, t2, base, &diff_opts);
diffcore_std(&diff_opts);
diff_tree_release_paths(&diff_opts);
/* Go through the new set of filepairing, and see if we find a more interesting one */
opt->found_follow = 0;
for (i = 0; i < q->nr; i++) {
struct diff_filepair *p = q->queue[i];
/*
* Found a source? Not only do we use that for the new
* diff_queued_diff, we will also use that as the path in
* the future!
*/
if ((p->status == 'R' || p->status == 'C') &&
!strcmp(p->two->path, opt->pathspec.raw[0])) {
/* Switch the file-pairs around */
q->queue[i] = choice;
choice = p;
/* Update the path we use from now on.. */
diff_tree_release_paths(opt);
opt->pathspec.raw[0] = xstrdup(p->one->path);
diff_tree_setup_paths(opt->pathspec.raw, opt);
/*
* The caller expects us to return a set of vanilla
* filepairs to let a later call to diffcore_std()
* it makes to sort the renames out (among other
* things), but we already have found renames
* ourselves; signal diffcore_std() not to muck with
* rename information.
*/
opt->found_follow = 1;
break;
}
}
/*
* Then, discard all the non-relevant file pairs...
*/
for (i = 0; i < q->nr; i++) {
struct diff_filepair *p = q->queue[i];
diff_free_filepair(p);
}
/*
* .. and re-instate the one we want (which might be either the
* original one, or the rename/copy we found)
*/
q->queue[0] = choice;
q->nr = 1;
}
int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
{
void *tree1, *tree2;
struct tree_desc t1, t2;
unsigned long size1, size2;
int retval;
tree1 = read_object_with_reference(old, tree_type, &size1, NULL);
if (!tree1)
die("unable to read source tree (%s)", sha1_to_hex(old));
tree2 = read_object_with_reference(new, tree_type, &size2, NULL);
if (!tree2)
die("unable to read destination tree (%s)", sha1_to_hex(new));
init_tree_desc(&t1, tree1, size1);
init_tree_desc(&t2, tree2, size2);
retval = diff_tree(&t1, &t2, base, opt);
if (!*base && DIFF_OPT_TST(opt, FOLLOW_RENAMES) && diff_might_be_rename()) {
init_tree_desc(&t1, tree1, size1);
init_tree_desc(&t2, tree2, size2);
try_to_follow_renames(&t1, &t2, base, opt);
}
free(tree1);
free(tree2);
return retval;
}
int diff_root_tree_sha1(const unsigned char *new, const char *base, struct diff_options *opt)
{
int retval;
void *tree;
unsigned long size;
struct tree_desc empty, real;
tree = read_object_with_reference(new, tree_type, &size, NULL);
if (!tree)
die("unable to read root tree (%s)", sha1_to_hex(new));
init_tree_desc(&real, tree, size);
init_tree_desc(&empty, "", 0);
retval = diff_tree(&empty, &real, base, opt);
free(tree);
return retval;
}
void diff_tree_release_paths(struct diff_options *opt)
{
free_pathspec(&opt->pathspec);
}
void diff_tree_setup_paths(const char **p, struct diff_options *opt)
{
init_pathspec(&opt->pathspec, p);
}