On Wed, Mar 26, 2014 at 02:34:24PM -0700, Junio C Hamano wrote:
> Kirill Smelkov <kirr@xxxxxxxxxxxxxx> writes:
>
> > On Tue, Mar 25, 2014 at 10:46:32AM -0700, Junio C Hamano wrote:
> >> Kirill Smelkov <kirr@xxxxxxxxxxxxxx> writes:
> >>
> >> > What are the downsides of "__" prefix by the way?
> >>
> >> Aren't these names reserved for compiler/runtime implementations?
> >
> > Yes, but there are precedents when people don't obey it widely and
> > in practice everything works :)
>
> I think you are alluding to the practice in the Linux kernel, but
> their requirement is vastly different---their product do not even
> link with libc and they always compile with specific selected
> versions of gcc, no?
Yes, that is correct. Only "__" was so visually appealing that there was
a temptation to break the rules, but...
> > Let it be something portable anyway -
> > how about diff_tree_sha1_low() ?
>
> Sure.
>
> As this is a file-scope static, I do not think the exact naming
> matters that much. Just FYI, we seem to use ll_ prefix (standing
> for low-level) in some places.
... let's then use this "ll_" prefix scheme for consistency.
Corrected patch is below, and I've sent corrections to follow-up
patches as well.
Thanks,
Kirill
(please keep author email)
---- 8< ----
From: Kirill Smelkov <kirr@xxxxxxxxxx>
Date: Mon, 24 Feb 2014 20:21:46 +0400
Subject: [PATCH v3a] tree-diff: rework diff_tree interface to be sha1 based
In the next commit this will allow to reduce intermediate calls, when
recursing into subtrees - at that stage we know only subtree sha1, and
it is natural for tree walker to start from that phase. For now we do
diff_tree
show_path
diff_tree_sha1
diff_tree
...
and the change will allow to reduce it to
diff_tree
show_path
diff_tree
Also, it will allow to omit allocating strbuf for each subtree, and just
reuse the common strbuf via playing with its len.
The above-mentioned improvements go in the next 2 patches.
The downside is that try_to_follow_renames(), if active, we cause
re-reading of 2 initial trees, which was negligible based on my timings,
and which is outweighed cogently by the upsides.
NOTE To keep with the current interface and semantics, I needed to
rename the function from diff_tree() to diff_tree_sha1(). As
diff_tree_sha1() was already used, and the function we are talking here
is its more low-level helper, let's use convention for prefixing
such helpers with "ll_". So the final renaming is
diff_tree() -> ll_diff_tree_sha1()
Signed-off-by: Kirill Smelkov <kirr@xxxxxxxxxx>
---
Changes since v3:
- further rename diff_tree_sha1_low() -> ll_diff_tree_sha1() to follow Git
style for naming low-level helpers.
Changes since v2:
- renamed __diff_tree_sha1() -> diff_tree_sha1_low() as the former
overlaps with reserved-for-implementation identifiers namespace.
Changes since v1:
- don't need to touch diff.h, as diff_tree() became static.
tree-diff.c | 60 ++++++++++++++++++++++++++++--------------------------------
1 file changed, 28 insertions(+), 32 deletions(-)
diff --git a/tree-diff.c b/tree-diff.c
index f137f39..1d02e43 100644
--- a/tree-diff.c
+++ b/tree-diff.c
@@ -141,12 +141,17 @@ static void skip_uninteresting(struct tree_desc *t, struct strbuf *base,
}
}
-static int diff_tree(struct tree_desc *t1, struct tree_desc *t2,
- const char *base_str, struct diff_options *opt)
+static int ll_diff_tree_sha1(const unsigned char *old, const unsigned char *new,
+ const char *base_str, struct diff_options *opt)
{
+ struct tree_desc t1, t2;
+ void *t1tree, *t2tree;
struct strbuf base;
int baselen = strlen(base_str);
+ t1tree = fill_tree_descriptor(&t1, old);
+ t2tree = fill_tree_descriptor(&t2, new);
+
/* Enable recursion indefinitely */
opt->pathspec.recursive = DIFF_OPT_TST(opt, RECURSIVE);
@@ -159,39 +164,41 @@ static int diff_tree(struct tree_desc *t1, struct tree_desc *t2,
if (diff_can_quit_early(opt))
break;
if (opt->pathspec.nr) {
- skip_uninteresting(t1, &base, opt);
- skip_uninteresting(t2, &base, opt);
+ skip_uninteresting(&t1, &base, opt);
+ skip_uninteresting(&t2, &base, opt);
}
- if (!t1->size && !t2->size)
+ if (!t1.size && !t2.size)
break;
- cmp = tree_entry_pathcmp(t1, t2);
+ cmp = tree_entry_pathcmp(&t1, &t2);
/* t1 = t2 */
if (cmp == 0) {
if (DIFF_OPT_TST(opt, FIND_COPIES_HARDER) ||
- hashcmp(t1->entry.sha1, t2->entry.sha1) ||
- (t1->entry.mode != t2->entry.mode))
- show_path(&base, opt, t1, t2);
+ hashcmp(t1.entry.sha1, t2.entry.sha1) ||
+ (t1.entry.mode != t2.entry.mode))
+ show_path(&base, opt, &t1, &t2);
- update_tree_entry(t1);
- update_tree_entry(t2);
+ update_tree_entry(&t1);
+ update_tree_entry(&t2);
}
/* t1 < t2 */
else if (cmp < 0) {
- show_path(&base, opt, t1, /*t2=*/NULL);
- update_tree_entry(t1);
+ show_path(&base, opt, &t1, /*t2=*/NULL);
+ update_tree_entry(&t1);
}
/* t1 > t2 */
else {
- show_path(&base, opt, /*t1=*/NULL, t2);
- update_tree_entry(t2);
+ show_path(&base, opt, /*t1=*/NULL, &t2);
+ update_tree_entry(&t2);
}
}
strbuf_release(&base);
+ free(t2tree);
+ free(t1tree);
return 0;
}
@@ -206,7 +213,7 @@ static inline int diff_might_be_rename(void)
!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)
+static void try_to_follow_renames(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
{
struct diff_options diff_opts;
struct diff_queue_struct *q = &diff_queued_diff;
@@ -244,7 +251,7 @@ static void try_to_follow_renames(struct tree_desc *t1, struct tree_desc *t2, co
diff_opts.break_opt = opt->break_opt;
diff_opts.rename_score = opt->rename_score;
diff_setup_done(&diff_opts);
- diff_tree(t1, t2, base, &diff_opts);
+ ll_diff_tree_sha1(old, new, base, &diff_opts);
diffcore_std(&diff_opts);
free_pathspec(&diff_opts.pathspec);
@@ -305,23 +312,12 @@ static void try_to_follow_renames(struct tree_desc *t1, struct tree_desc *t2, co
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 = fill_tree_descriptor(&t1, old);
- tree2 = fill_tree_descriptor(&t2, new);
- size1 = t1.size;
- size2 = t2.size;
- 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);
+ retval = ll_diff_tree_sha1(old, new, base, opt);
+ if (!*base && DIFF_OPT_TST(opt, FOLLOW_RENAMES) && diff_might_be_rename())
+ try_to_follow_renames(old, new, base, opt);
+
return retval;
}
--
1.9.rc0.143.g6fd479e
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