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tree-diff: consolidate code for emitting diffs and recursion in one place

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Currently both compare_tree_entry() and show_entry() invoke opt diff
callbacks (opt->add_remove() and opt->change()), and also they both have
code which decides whether to recurse into sub-tree, and whether to emit
a tree as separate entry if DIFF_OPT_TREE_IN_RECURSIVE is set.

I.e. we have code duplication and logic scattered on two places.

Let's consolidate it - all diff emiting code and recurion logic moves
to show_entry, which is now named as show_path, because it shows diff
for a path, based on up to two tree entries, with actual diff emitting
code being kept in new helper emit_diff() for clarity.

What we have as the result, is that compare_tree_entry is now free from
code with logic for diff generation, and also performance is not
affected as timings for

    `git log --raw --no-abbrev --no-renames`

for navy.git and `linux.git v3.10..v3.11`, just like in previous patch,
stay the same.

Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Kirill Smelkov 2014-02-24 20:21:38 +04:00 committed by Junio C Hamano
parent 7e9003c149
commit d00e980c22
1 changed files with 83 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

114
tree-diff.c
View File

@ -6,8 +6,8 @@
#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 void show_path(struct strbuf *base, struct diff_options *opt,
struct tree_desc *t1, struct tree_desc *t2);
static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2,
struct strbuf *base, struct diff_options *opt)
@ -16,7 +16,6 @@ static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2,
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);
@ -30,51 +29,104 @@ static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2,
*/
cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
if (cmp < 0) {
show_entry(opt, "-", t1, base);
show_path(base, opt, t1, /*t2=*/NULL);
return -1;
}
if (cmp > 0) {
show_entry(opt, "+", t2, base);
show_path(base, opt, /*t1=*/NULL, t2);
return 1;
}
if (!DIFF_OPT_TST(opt, FIND_COPIES_HARDER) && !hashcmp(sha1, sha2) && mode1 == mode2)
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, 1, 1, base->buf, 0, 0);
}
strbuf_addch(base, '/');
diff_tree_sha1(sha1, sha2, base->buf, opt);
} else {
opt->change(opt, mode1, mode2, sha1, sha2, 1, 1, base->buf, 0, 0);
}
strbuf_setlen(base, old_baselen);
show_path(base, opt, t1, t2);
return 0;
}
/* An entry went away or appeared */
static void show_entry(struct diff_options *opt, const char *prefix,
struct tree_desc *desc, struct strbuf *base)
/* convert path, t1/t2 -> opt->diff_*() callbacks */
static void emit_diff(struct diff_options *opt, struct strbuf *path,
struct tree_desc *t1, struct tree_desc *t2)
{
unsigned int mode1 = t1 ? t1->entry.mode : 0;
unsigned int mode2 = t2 ? t2->entry.mode : 0;
if (mode1 && mode2) {
opt->change(opt, mode1, mode2, t1->entry.sha1, t2->entry.sha1,
1, 1, path->buf, 0, 0);
}
else {
const unsigned char *sha1;
unsigned int mode;
int addremove;
if (mode2) {
addremove = '+';
sha1 = t2->entry.sha1;
mode = mode2;
} else {
addremove = '-';
sha1 = t1->entry.sha1;
mode = mode1;
}
opt->add_remove(opt, addremove, mode, sha1, 1, path->buf, 0);
}
}
/* new path should be added to diff
*
* 3 cases on how/when it should be called and behaves:
*
* !t1, t2 -> path added, parent lacks it
* t1, !t2 -> path removed from parent
* t1, t2 -> path modified
*/
static void show_path(struct strbuf *base, struct diff_options *opt,
struct tree_desc *t1, struct tree_desc *t2)
{
unsigned mode;
const char *path;
const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
int pathlen = tree_entry_len(&desc->entry);
int pathlen;
int old_baselen = base->len;
int isdir, recurse = 0, emitthis = 1;
/* at least something has to be valid */
assert(t1 || t2);
if (t2) {
/* path present in resulting tree */
tree_entry_extract(t2, &path, &mode);
pathlen = tree_entry_len(&t2->entry);
isdir = S_ISDIR(mode);
} else {
/*
* a path was removed - take path from parent. Also take
* mode from parent, to decide on recursion.
*/
tree_entry_extract(t1, &path, &mode);
pathlen = tree_entry_len(&t1->entry);
isdir = S_ISDIR(mode);
mode = 0;
}
if (DIFF_OPT_TST(opt, RECURSIVE) && isdir) {
recurse = 1;
emitthis = DIFF_OPT_TST(opt, TREE_IN_RECURSIVE);
}
strbuf_add(base, path, pathlen);
if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode)) {
if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE))
opt->add_remove(opt, *prefix, mode, sha1, 1, base->buf, 0);
if (emitthis)
emit_diff(opt, base, t1, t2);
if (recurse) {
strbuf_addch(base, '/');
diff_tree_sha1(*prefix == '-' ? sha1 : NULL,
*prefix == '+' ? sha1 : NULL, base->buf, opt);
} else
opt->add_remove(opt, prefix[0], mode, sha1, 1, base->buf, 0);
diff_tree_sha1(t1 ? t1->entry.sha1 : NULL,
t2 ? t2->entry.sha1 : NULL, base->buf, opt);
}
strbuf_setlen(base, old_baselen);
}
@ -117,12 +169,12 @@ int diff_tree(struct tree_desc *t1, struct tree_desc *t2,
if (!t1->size) {
if (!t2->size)
break;
show_entry(opt, "+", t2, &base);
show_path(&base, opt, /*t1=*/NULL, t2);
update_tree_entry(t2);
continue;
}
if (!t2->size) {
show_entry(opt, "-", t1, &base);
show_path(&base, opt, t1, /*t2=*/NULL);
update_tree_entry(t1);
continue;
}