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git-pickaxe: improve "best match" heuristics 

Instead of comparing number of lines matched, look at the
matched characters and count alnums, so that we do not pass
blame on not-so-interesting lines, such as an empty line and
a line that is indentation followed by a closing brace.

Add an option --score-debug to show the score of each
blame_entry while we cook this further on the "next" branch.

Signed-off-by: Junio C Hamano <junkio@cox.net>
maint
Junio C Hamano 2006-10-20 14:51:12 -07:00
parent 1ca6ca876e
commit 5ff62c3002
1 changed files with 48 additions and 23 deletions
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71
builtin-pickaxe.c
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@ -34,8 +34,7 @@ static int longest_file;
static int longest_author;
static int max_orig_digits;
static int max_digits;

#define DEBUG 0
static int max_score_digits;

#define PICKAXE_BLAME_MOVE 01
#define PICKAXE_BLAME_COPY 02
@ -78,6 +77,11 @@ struct blame_entry {
* suspect's file; internally all line numbers are 0 based.
*/
int s_lno;

/* how significant this entry is -- cached to avoid
* scanning the lines over and over
*/
unsigned score;
};

struct scoreboard {
@ -215,9 +219,6 @@ static void process_u_diff(void *state_, char *line, unsigned long len)
struct chunk *chunk;
int off1, off2, len1, len2, num;

if (DEBUG)
fprintf(stderr, "%.*s", (int) len, line);

num = state->ret->num;
if (len < 4 || line[0] != '@' || line[1] != '@') {
if (state->hunk_in_pre_context && line[0] == ' ')
@ -295,10 +296,6 @@ static struct patch *get_patch(struct origin *parent, struct origin *origin)
char *blob_p, *blob_o;
struct patch *patch;

if (DEBUG) fprintf(stderr, "get patch %.8s %.8s\n",
sha1_to_hex(parent->commit->object.sha1),
sha1_to_hex(origin->commit->object.sha1));

blob_p = read_sha1_file(parent->blob_sha1, type,
(unsigned long *) &file_p.size);
blob_o = read_sha1_file(origin->blob_sha1, type,
@ -352,6 +349,7 @@ static void dup_entry(struct blame_entry *dst, struct blame_entry *src)
memcpy(dst, src, sizeof(*src));
dst->prev = p;
dst->next = n;
dst->score = 0;
}

static const char *nth_line(struct scoreboard *sb, int lno)
@ -448,7 +446,7 @@ static void split_blame(struct scoreboard *sb,
add_blame_entry(sb, new_entry);
}

if (DEBUG) {
if (1) { /* sanity */
struct blame_entry *ent;
int lno = 0, corrupt = 0;

@ -530,12 +528,6 @@ static int pass_blame_to_parent(struct scoreboard *sb,
for (i = 0; i < patch->num; i++) {
struct chunk *chunk = &patch->chunks[i];

if (DEBUG)
fprintf(stderr,
"plno = %d, tlno = %d, "
"same as parent up to %d, resync %d and %d\n",
plno, tlno,
chunk->same, chunk->p_next, chunk->t_next);
blame_chunk(sb, tlno, plno, chunk->same, target, parent);
plno = chunk->p_next;
tlno = chunk->t_next;
@ -547,14 +539,37 @@ static int pass_blame_to_parent(struct scoreboard *sb,
return 0;
}

static void copy_split_if_better(struct blame_entry best_so_far[3],
static unsigned ent_score(struct scoreboard *sb, struct blame_entry *e)
{
unsigned score;
const char *cp, *ep;

if (e->score)
return e->score;

score = 0;
cp = nth_line(sb, e->lno);
ep = nth_line(sb, e->lno + e->num_lines);
while (cp < ep) {
unsigned ch = *((unsigned char *)cp);
if (isalnum(ch))
score++;
cp++;
}
e->score = score;
return score;
}

static void copy_split_if_better(struct scoreboard *sb,
struct blame_entry best_so_far[3],
struct blame_entry this[3])
{
if (!this[1].suspect)
return;
if (best_so_far[1].suspect &&
(this[1].num_lines < best_so_far[1].num_lines))
return;
if (best_so_far[1].suspect) {
if (ent_score(sb, &this[1]) < ent_score(sb, &best_so_far[1]))
return;
}
memcpy(best_so_far, this, sizeof(struct blame_entry [3]));
}

@ -596,7 +611,7 @@ static void find_copy_in_blob(struct scoreboard *sb,
tlno + ent->s_lno, plno,
chunk->same + ent->s_lno,
parent);
copy_split_if_better(split, this);
copy_split_if_better(sb, split, this);
}
plno = chunk->p_next;
tlno = chunk->t_next;
@ -699,7 +714,7 @@ static int find_copy_in_parent(struct scoreboard *sb,
continue;
}
find_copy_in_blob(sb, ent, norigin, this, &file_p);
copy_split_if_better(split, this);
copy_split_if_better(sb, split, this);
}
if (split[1].suspect)
split_blame(sb, split, ent);
@ -944,6 +959,7 @@ static void get_commit_info(struct commit *commit,
#define OUTPUT_PORCELAIN 010
#define OUTPUT_SHOW_NAME 020
#define OUTPUT_SHOW_NUMBER 040
#define OUTPUT_SHOW_SCORE 0100

static void emit_porcelain(struct scoreboard *sb, struct blame_entry *ent)
{
@ -1016,6 +1032,8 @@ static void emit_other(struct scoreboard *sb, struct blame_entry *ent, int opt)
show_raw_time),
ent->lno + 1 + cnt);
else {
if (opt & OUTPUT_SHOW_SCORE)
printf(" %*d", max_score_digits, ent->score);
if (opt & OUTPUT_SHOW_NAME)
printf(" %-*.*s", longest_file, longest_file,
suspect->path);
@ -1060,8 +1078,9 @@ static void output(struct scoreboard *sb, int option)
for (ent = sb->ent; ent; ent = ent->next) {
if (option & OUTPUT_PORCELAIN)
emit_porcelain(sb, ent);
else
else {
emit_other(sb, ent, option);
}
}
}

@ -1121,6 +1140,7 @@ static void find_alignment(struct scoreboard *sb, int *option)
{
int longest_src_lines = 0;
int longest_dst_lines = 0;
unsigned largest_score = 0;
struct blame_entry *e;

for (e = sb->ent; e; e = e->next) {
@ -1146,9 +1166,12 @@ static void find_alignment(struct scoreboard *sb, int *option)
num = e->lno + e->num_lines;
if (longest_dst_lines < num)
longest_dst_lines = num;
if (largest_score < ent_score(sb, e))
largest_score = ent_score(sb, e);
}
max_orig_digits = lineno_width(longest_src_lines);
max_digits = lineno_width(longest_dst_lines);
max_score_digits = lineno_width(largest_score);
}

static int has_path_in_work_tree(const char *path)
@ -1209,6 +1232,8 @@ int cmd_pickaxe(int argc, const char **argv, const char *prefix)
tmp = top; top = bottom; bottom = tmp;
}
}
else if (!strcmp("--score-debug", arg))
output_option |= OUTPUT_SHOW_SCORE;
else if (!strcmp("-f", arg) ||
!strcmp("--show-name", arg))
output_option |= OUTPUT_SHOW_NAME;