git/tree-diff.c
Nguyễn Thái Ngọc Duy d688cf07b1 tree_entry_interesting(): give meaningful names to return values
It is a basic code hygiene to avoid magic constants that are unnamed.
Besides, this helps extending the value later on for "interesting, but
cannot decide if the entry truely matches yet" (ie. prefix matches)

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-10-27 11:38:24 -07:00

323 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;
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);
}