git/builtin/diff-tree.c
Jeff King b794ebeac9 diff-tree: avoid lookup_unknown_object
We generally want to avoid lookup_unknown_object, because it
results in allocating more memory for the object than may be
strictly necessary.

In this case, it is used to check whether we have an
already-parsed object before calling parse_object, to save
us from reading the object from disk. Using lookup_object
would be fine for that purpose, but we can take it a step
further. Since this code was written, parse_object already
learned the "check lookup_object" optimization, so we can
simply call parse_object directly.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-07-28 10:14:34 -07:00

191 lines
4.8 KiB
C

#include "cache.h"
#include "diff.h"
#include "commit.h"
#include "log-tree.h"
#include "builtin.h"
#include "submodule.h"
static struct rev_info log_tree_opt;
static int diff_tree_commit_sha1(const unsigned char *sha1)
{
struct commit *commit = lookup_commit_reference(sha1);
if (!commit)
return -1;
return log_tree_commit(&log_tree_opt, commit);
}
/* Diff one or more commits. */
static int stdin_diff_commit(struct commit *commit, char *line, int len)
{
unsigned char sha1[20];
if (isspace(line[40]) && !get_sha1_hex(line+41, sha1)) {
/* Graft the fake parents locally to the commit */
int pos = 41;
struct commit_list **pptr, *parents;
/* Free the real parent list */
for (parents = commit->parents; parents; ) {
struct commit_list *tmp = parents->next;
free(parents);
parents = tmp;
}
commit->parents = NULL;
pptr = &(commit->parents);
while (line[pos] && !get_sha1_hex(line + pos, sha1)) {
struct commit *parent = lookup_commit(sha1);
if (parent) {
pptr = &commit_list_insert(parent, pptr)->next;
}
pos += 41;
}
}
return log_tree_commit(&log_tree_opt, commit);
}
/* Diff two trees. */
static int stdin_diff_trees(struct tree *tree1, char *line, int len)
{
unsigned char sha1[20];
struct tree *tree2;
if (len != 82 || !isspace(line[40]) || get_sha1_hex(line + 41, sha1))
return error("Need exactly two trees, separated by a space");
tree2 = lookup_tree(sha1);
if (!tree2 || parse_tree(tree2))
return -1;
printf("%s %s\n", sha1_to_hex(tree1->object.sha1),
sha1_to_hex(tree2->object.sha1));
diff_tree_sha1(tree1->object.sha1, tree2->object.sha1,
"", &log_tree_opt.diffopt);
log_tree_diff_flush(&log_tree_opt);
return 0;
}
static int diff_tree_stdin(char *line)
{
int len = strlen(line);
unsigned char sha1[20];
struct object *obj;
if (!len || line[len-1] != '\n')
return -1;
line[len-1] = 0;
if (get_sha1_hex(line, sha1))
return -1;
obj = parse_object(sha1);
if (!obj)
return -1;
if (obj->type == OBJ_COMMIT)
return stdin_diff_commit((struct commit *)obj, line, len);
if (obj->type == OBJ_TREE)
return stdin_diff_trees((struct tree *)obj, line, len);
error("Object %s is a %s, not a commit or tree",
sha1_to_hex(sha1), typename(obj->type));
return -1;
}
static const char diff_tree_usage[] =
"git diff-tree [--stdin] [-m] [-c] [--cc] [-s] [-v] [--pretty] [-t] [-r] [--root] "
"[<common diff options>] <tree-ish> [<tree-ish>] [<path>...]\n"
" -r diff recursively\n"
" --root include the initial commit as diff against /dev/null\n"
COMMON_DIFF_OPTIONS_HELP;
static void diff_tree_tweak_rev(struct rev_info *rev, struct setup_revision_opt *opt)
{
if (!rev->diffopt.output_format) {
if (rev->dense_combined_merges)
rev->diffopt.output_format = DIFF_FORMAT_PATCH;
else
rev->diffopt.output_format = DIFF_FORMAT_RAW;
}
}
int cmd_diff_tree(int argc, const char **argv, const char *prefix)
{
int nr_sha1;
char line[1000];
struct object *tree1, *tree2;
static struct rev_info *opt = &log_tree_opt;
struct setup_revision_opt s_r_opt;
int read_stdin = 0;
init_revisions(opt, prefix);
gitmodules_config();
git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
opt->abbrev = 0;
opt->diff = 1;
opt->disable_stdin = 1;
memset(&s_r_opt, 0, sizeof(s_r_opt));
s_r_opt.tweak = diff_tree_tweak_rev;
argc = setup_revisions(argc, argv, opt, &s_r_opt);
while (--argc > 0) {
const char *arg = *++argv;
if (!strcmp(arg, "--stdin")) {
read_stdin = 1;
continue;
}
usage(diff_tree_usage);
}
/*
* NOTE! We expect "a ^b" to be equal to "a..b", so we
* reverse the order of the objects if the second one
* is marked UNINTERESTING.
*/
nr_sha1 = opt->pending.nr;
switch (nr_sha1) {
case 0:
if (!read_stdin)
usage(diff_tree_usage);
break;
case 1:
tree1 = opt->pending.objects[0].item;
diff_tree_commit_sha1(tree1->sha1);
break;
case 2:
tree1 = opt->pending.objects[0].item;
tree2 = opt->pending.objects[1].item;
if (tree2->flags & UNINTERESTING) {
struct object *tmp = tree2;
tree2 = tree1;
tree1 = tmp;
}
diff_tree_sha1(tree1->sha1,
tree2->sha1,
"", &opt->diffopt);
log_tree_diff_flush(opt);
break;
}
if (read_stdin) {
int saved_nrl = 0;
int saved_dcctc = 0;
if (opt->diffopt.detect_rename)
opt->diffopt.setup |= (DIFF_SETUP_USE_SIZE_CACHE |
DIFF_SETUP_USE_CACHE);
while (fgets(line, sizeof(line), stdin)) {
unsigned char sha1[20];
if (get_sha1_hex(line, sha1)) {
fputs(line, stdout);
fflush(stdout);
}
else {
diff_tree_stdin(line);
if (saved_nrl < opt->diffopt.needed_rename_limit)
saved_nrl = opt->diffopt.needed_rename_limit;
if (opt->diffopt.degraded_cc_to_c)
saved_dcctc = 1;
}
}
opt->diffopt.degraded_cc_to_c = saved_dcctc;
opt->diffopt.needed_rename_limit = saved_nrl;
}
return diff_result_code(&opt->diffopt, 0);
}