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git/builtin-diff-tree.c
Linus Torvalds 1f1e895fcc Add "named object array" concept
We've had this notion of a "object_list" for a long time, which eventually
grew a "name" member because some users (notably git-rev-list) wanted to
name each object as it is generated.

That object_list is great for some things, but it isn't all that wonderful
for others, and the "name" member is generally not used by everybody.

This patch splits the users of the object_list array up into two: the
traditional list users, who want the list-like format, and who don't
actually use or want the name. And another class of users that really used
the list as an extensible array, and generally wanted to name the objects.

The patch is fairly straightforward, but it's also biggish. Most of it
really just cleans things up: switching the revision parsing and listing
over to the array makes things like the builtin-diff usage much simpler
(we now see exactly how many members the array has, and we don't get the
objects reversed from the order they were on the command line).

One of the main reasons for doing this at all is that the malloc overhead
of the simple object list was actually pretty high, and the array is just
a lot denser. So this patch brings down memory usage by git-rev-list by
just under 3% (on top of all the other memory use optimizations) on the
mozilla archive.

It does add more lines than it removes, and more importantly, it adds a
whole new infrastructure for maintaining lists of objects, but on the
other hand, the new dynamic array code is pretty obvious. The change to
builtin-diff-tree.c shows a fairly good example of why an array interface
is sometimes more natural, and just much simpler for everybody.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-06-19 18:45:48 -07:00

134 lines
3.1 KiB
C

#include "cache.h"
#include "diff.h"
#include "commit.h"
#include "log-tree.h"
#include "builtin.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);
}
static int diff_tree_stdin(char *line)
{
int len = strlen(line);
unsigned char sha1[20];
struct commit *commit;
if (!len || line[len-1] != '\n')
return -1;
line[len-1] = 0;
if (get_sha1_hex(line, sha1))
return -1;
commit = lookup_commit(sha1);
if (!commit || parse_commit(commit))
return -1;
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);
}
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;
int cmd_diff_tree(int argc, const char **argv, char **envp)
{
int nr_sha1;
char line[1000];
struct object *tree1, *tree2;
static struct rev_info *opt = &log_tree_opt;
int read_stdin = 0;
git_config(git_diff_config);
nr_sha1 = 0;
init_revisions(opt);
opt->abbrev = 0;
opt->diff = 1;
argc = setup_revisions(argc, argv, opt, NULL);
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)
return 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);
}
return 0;
}