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authorJunio C Hamano <junkio@cox.net>2005-05-19 10:32:35 (GMT)
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-05-19 15:59:40 (GMT)
commit5c97558c9a813a0a775c438a79cfc438def00c22 (patch)
tree59b9eaa38cd2ec6f846ed2f2b6767055022a227a /diff.c
parenta310d4349467d78266f38d29e500c77b96ee5bef (diff)
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[PATCH] Detect renames in diff family.
This rips out the rename detection engine from diff-helper and moves it to the diff core, and updates the internal calling convention used by diff-tree family into the diff core. In order to give the same option name to diff-tree family as well as to diff-helper, I've changed the earlier diff-helper '-r' option to '-M' (stands for Move; sorry but the natural abbreviation 'r' for 'rename' is already taken for 'recursive'). Although I did a fair amount of test with the git-diff-tree with existing rename commits in the core GIT repository, this should still be considered beta (preview) release. This patch depends on the diff-delta infrastructure just committed. This implements almost everything I wanted to see in this series of patch, except a few minor cleanups in the calling convention into diff core, but that will be a separate cleanup patch. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'diff.c')
-rw-r--r--diff.c410
1 files changed, 378 insertions, 32 deletions
diff --git a/diff.c b/diff.c
index 74004e5..1f9cfa8 100644
--- a/diff.c
+++ b/diff.c
@@ -7,8 +7,10 @@
#include <limits.h>
#include "cache.h"
#include "diff.h"
+#include "delta.h"
static const char *diff_opts = "-pu";
+static unsigned char null_sha1[20] = { 0, };
static const char *external_diff(void)
{
@@ -79,6 +81,18 @@ static struct diff_tempfile {
char tmp_path[50];
} diff_temp[2];
+struct diff_spec {
+ unsigned char blob_sha1[20];
+ unsigned short mode; /* file mode */
+ unsigned sha1_valid : 1; /* if true, use blob_sha1 and trust mode;
+ * however with a NULL SHA1, read them
+ * from the file system.
+ * if false, use the name and read mode from
+ * the filesystem.
+ */
+ unsigned file_valid : 1; /* if false the file does not even exist */
+};
+
static void builtin_diff(const char *name_a,
const char *name_b,
struct diff_tempfile *temp)
@@ -160,7 +174,7 @@ static int work_tree_matches(const char *name, const unsigned char *sha1)
struct cache_entry *ce;
struct stat st;
int pos, len;
-
+
/* We do not read the cache ourselves here, because the
* benchmark with my previous version that always reads cache
* shows that it makes things worse for diff-tree comparing
@@ -214,9 +228,6 @@ static void prepare_temp_file(const char *name,
struct diff_tempfile *temp,
struct diff_spec *one)
{
- static unsigned char null_sha1[20] = { 0, };
- int use_work_tree = 0;
-
if (!one->file_valid) {
not_a_valid_file:
/* A '-' entry produces this for file-2, and
@@ -228,12 +239,8 @@ static void prepare_temp_file(const char *name,
return;
}
- if (one->sha1_valid &&
- (!memcmp(one->blob_sha1, null_sha1, sizeof(null_sha1)) ||
- work_tree_matches(name, one->blob_sha1)))
- use_work_tree = 1;
-
- if (!one->sha1_valid || use_work_tree) {
+ if (!one->sha1_valid ||
+ work_tree_matches(name, one->blob_sha1)) {
struct stat st;
temp->name = name;
if (lstat(temp->name, &st) < 0) {
@@ -295,22 +302,59 @@ static void remove_tempfile_on_signal(int signo)
remove_tempfile();
}
+static int detect_rename;
+static int reverse_diff;
+static const char **pathspec;
+static int speccnt;
+static int diff_rename_minimum_score;
+
+static int matches_pathspec(const char *name)
+{
+ int i;
+ int namelen;
+
+ if (speccnt == 0)
+ return 1;
+
+ namelen = strlen(name);
+ for (i = 0; i < speccnt; i++) {
+ int speclen = strlen(pathspec[i]);
+ if (! strncmp(pathspec[i], name, speclen) &&
+ speclen <= namelen &&
+ (name[speclen] == 0 || name[speclen] == '/'))
+ return 1;
+ }
+ return 0;
+}
+
/* An external diff command takes:
*
* diff-cmd name infile1 infile1-sha1 infile1-mode \
- * infile2 infile2-sha1 infile2-mode.
+ * infile2 infile2-sha1 infile2-mode [ rename-to ]
*
*/
-void run_external_diff(const char *name,
- const char *other,
- struct diff_spec *one,
- struct diff_spec *two)
+static void run_external_diff(const char *name,
+ const char *other,
+ struct diff_spec *one,
+ struct diff_spec *two)
{
struct diff_tempfile *temp = diff_temp;
pid_t pid;
int status;
static int atexit_asked = 0;
+ if (reverse_diff) {
+ struct diff_spec *tmp_spec;
+ tmp_spec = one; one = two; two = tmp_spec;
+ if (other) {
+ const char *tmp;
+ tmp = name; name = other; other = tmp;
+ }
+ }
+
+ if (!matches_pathspec(name) && (!other || !matches_pathspec(other)))
+ return;
+
if (one && two) {
prepare_temp_file(name, &temp[0], one);
prepare_temp_file(other ? : name, &temp[1], two);
@@ -329,14 +373,23 @@ void run_external_diff(const char *name,
die("unable to fork");
if (!pid) {
const char *pgm = external_diff();
- /* not passing rename patch to external ones */
- if (!other && pgm) {
- if (one && two)
- execlp(pgm, pgm,
- name,
- temp[0].name, temp[0].hex, temp[0].mode,
- temp[1].name, temp[1].hex, temp[1].mode,
- NULL);
+ if (pgm) {
+ if (one && two) {
+ const char *exec_arg[9];
+ const char **arg = &exec_arg[0];
+ *arg++ = pgm;
+ *arg++ = name;
+ *arg++ = temp[0].name;
+ *arg++ = temp[0].hex;
+ *arg++ = temp[0].mode;
+ *arg++ = temp[1].name;
+ *arg++ = temp[1].hex;
+ *arg++ = temp[1].mode;
+ if (other)
+ *arg++ = other;
+ *arg = 0;
+ execvp(pgm, (char *const*) exec_arg);
+ }
else
execlp(pgm, pgm, name, NULL);
}
@@ -367,6 +420,293 @@ void run_external_diff(const char *name,
remove_tempfile();
}
+/*
+ * We do not detect circular renames. Just hold created and deleted
+ * entries and later attempt to match them up. If they do not match,
+ * then spit them out as deletes or creates as original.
+ */
+
+static struct diff_spec_hold {
+ struct diff_spec_hold *next;
+ struct diff_spec it;
+ unsigned long size;
+ int flags;
+#define MATCHED 1
+#define SHOULD_FREE 2
+#define SHOULD_MUNMAP 4
+ void *data;
+ char path[1];
+} *createdfile, *deletedfile;
+
+static void hold_diff(const char *name,
+ struct diff_spec *one,
+ struct diff_spec *two)
+{
+ struct diff_spec_hold **list, *elem;
+
+ if (one->file_valid && two->file_valid)
+ die("internal error");
+
+ if (!detect_rename) {
+ run_external_diff(name, NULL, one, two);
+ return;
+ }
+ elem = xmalloc(sizeof(*elem) + strlen(name));
+ strcpy(elem->path, name);
+ elem->size = 0;
+ elem->data = NULL;
+ elem->flags = 0;
+ if (one->file_valid) {
+ list = &deletedfile;
+ elem->it = *one;
+ }
+ else {
+ list = &createdfile;
+ elem->it = *two;
+ }
+ elem->next = *list;
+ *list = elem;
+}
+
+static int populate_data(struct diff_spec_hold *s)
+{
+ char type[20];
+
+ if (s->data)
+ return 0;
+ if (s->it.sha1_valid) {
+ s->data = read_sha1_file(s->it.blob_sha1, type, &s->size);
+ s->flags |= SHOULD_FREE;
+ }
+ else {
+ struct stat st;
+ int fd;
+ fd = open(s->path, O_RDONLY);
+ if (fd < 0)
+ return -1;
+ if (fstat(fd, &st)) {
+ close(fd);
+ return -1;
+ }
+ s->size = st.st_size;
+ s->data = mmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
+ close(fd);
+ if (!s->size)
+ s->data = "";
+ else
+ s->flags |= SHOULD_MUNMAP;
+ }
+ return 0;
+}
+
+static void free_data(struct diff_spec_hold *s)
+{
+ if (s->flags & SHOULD_FREE)
+ free(s->data);
+ else if (s->flags & SHOULD_MUNMAP)
+ munmap(s->data, s->size);
+ s->flags &= ~(SHOULD_FREE|SHOULD_MUNMAP);
+}
+
+static void flush_remaining_diff(struct diff_spec_hold *elem,
+ int on_created_list)
+{
+ static struct diff_spec null_file_spec;
+
+ null_file_spec.file_valid = 0;
+ for ( ; elem ; elem = elem->next) {
+ free_data(elem);
+ if (elem->flags & MATCHED)
+ continue;
+ if (on_created_list)
+ run_external_diff(elem->path, NULL,
+ &null_file_spec, &elem->it);
+ else
+ run_external_diff(elem->path, NULL,
+ &elem->it, &null_file_spec);
+ }
+}
+
+static int is_exact_match(struct diff_spec_hold *src,
+ struct diff_spec_hold *dst)
+{
+ if (src->it.sha1_valid && dst->it.sha1_valid &&
+ !memcmp(src->it.blob_sha1, dst->it.blob_sha1, 20))
+ return 1;
+ if (populate_data(src) || populate_data(dst))
+ /* this is an error but will be caught downstream */
+ return 0;
+ if (src->size == dst->size &&
+ !memcmp(src->data, dst->data, src->size))
+ return 1;
+ return 0;
+}
+
+#define MINIMUM_SCORE 5000
+int estimate_similarity(struct diff_spec_hold *src, struct diff_spec_hold *dst)
+{
+ /* src points at a deleted file and dst points at a created
+ * file. They may be quite similar, in which case we want to
+ * say src is renamed to dst.
+ *
+ * Compare them and return how similar they are, representing
+ * the score as an integer between 0 and 10000. 10000 is
+ * reserved for the case where they match exactly.
+ */
+ void *delta;
+ unsigned long delta_size;
+
+ delta_size = ((src->size < dst->size) ?
+ (dst->size - src->size) : (src->size - dst->size));
+
+ /* We would not consider rename followed by more than
+ * 20% edits; that is, delta_size must be smaller than
+ * (src->size + dst->size)/2 * 0.2, which means...
+ */
+ if ((src->size + dst->size) < delta_size * 10)
+ return 0;
+
+ delta = diff_delta(src->data, src->size,
+ dst->data, dst->size,
+ &delta_size);
+ free(delta);
+
+ /* This "delta" is really xdiff with adler32 and all the
+ * overheads but it is a quick and dirty approximation.
+ *
+ * Now we will give some score to it. Let's say 20% edit gets
+ * 5000 points and 0% edit gets 9000 points. That is, every
+ * 1/20000 edit gets 1 point penalty. The amount of penalty is:
+ *
+ * (delta_size * 2 / (src->size + dst->size)) * 20000
+ *
+ */
+ return 9000 - (40000 * delta_size / (src->size+dst->size));
+}
+
+struct diff_score {
+ struct diff_spec_hold *src;
+ struct diff_spec_hold *dst;
+ int score;
+};
+
+static int score_compare(const void *a_, const void *b_)
+{
+ const struct diff_score *a = a_, *b = b_;
+ return b->score - a->score;
+}
+
+static void flush_rename_pair(struct diff_spec_hold *src,
+ struct diff_spec_hold *dst)
+{
+ src->flags |= MATCHED;
+ dst->flags |= MATCHED;
+ free_data(src);
+ free_data(dst);
+ run_external_diff(src->path, dst->path,
+ &src->it, &dst->it);
+}
+
+static void free_held_diff(struct diff_spec_hold *list)
+{
+ struct diff_spec_hold *h;
+ for (h = list; list; list = h) {
+ h = list->next;
+ free_data(list);
+ free(list);
+ }
+}
+
+void diff_flush(void)
+{
+ int num_create, num_delete, c, d;
+ struct diff_spec_hold *elem, *src, *dst;
+ struct diff_score *mx;
+
+ /* We really want to cull the candidates list early
+ * with cheap tests in order to avoid doing deltas.
+ */
+ for (dst = createdfile; dst; dst = dst->next) {
+ for (src = deletedfile; src; src = src->next) {
+ if (! is_exact_match(src, dst))
+ continue;
+ flush_rename_pair(src, dst);
+ break;
+ }
+ }
+
+ /* Count surviving candidates */
+ for (num_create = 0, elem = createdfile; elem; elem = elem->next)
+ if (!(elem->flags & MATCHED))
+ num_create++;
+
+ for (num_delete = 0, elem = deletedfile; elem; elem = elem->next)
+ if (!(elem->flags & MATCHED))
+ num_delete++;
+
+ if (num_create == 0 || num_delete == 0)
+ goto exit_path;
+
+ mx = xmalloc(sizeof(*mx) * num_create * num_delete);
+ for (c = 0, dst = createdfile; dst; dst = dst->next) {
+ int base = c * num_delete;
+ if (dst->flags & MATCHED)
+ continue;
+ for (d = 0, src = deletedfile; src; src = src->next) {
+ struct diff_score *m = &mx[base+d];
+ if (src->flags & MATCHED)
+ continue;
+ m->src = src;
+ m->dst = dst;
+ m->score = estimate_similarity(src, dst);
+ d++;
+ }
+ c++;
+ }
+ qsort(mx, num_create*num_delete, sizeof(*mx), score_compare);
+
+ for (c = 0; c < num_create * num_delete; c++) {
+ src = mx[c].src;
+ dst = mx[c].dst;
+ if ((src->flags & MATCHED) || (dst->flags & MATCHED))
+ continue;
+ fprintf(stderr,
+ "**score ** %d %s %s\n",
+ mx[c].score, src->path, dst->path);
+ }
+
+ for (c = 0; c < num_create * num_delete; c++) {
+ src = mx[c].src;
+ dst = mx[c].dst;
+ if ((src->flags & MATCHED) || (dst->flags & MATCHED))
+ continue;
+ if (mx[c].score < diff_rename_minimum_score)
+ break;
+ flush_rename_pair(src, dst);
+ }
+
+ exit_path:
+ flush_remaining_diff(createdfile, 1);
+ flush_remaining_diff(deletedfile, 0);
+ free_held_diff(createdfile);
+ free_held_diff(deletedfile);
+ createdfile = deletedfile = NULL;
+}
+
+void diff_setup(int detect_rename_, int minimum_score_, int reverse_diff_,
+ const char **pathspec_, int speccnt_)
+{
+ free_held_diff(createdfile);
+ free_held_diff(deletedfile);
+ createdfile = deletedfile = NULL;
+
+ detect_rename = detect_rename_;
+ reverse_diff = reverse_diff_;
+ pathspec = pathspec_;
+ speccnt = speccnt_;
+ diff_rename_minimum_score = minimum_score_ ? : MINIMUM_SCORE;
+}
+
void diff_addremove(int addremove, unsigned mode,
const unsigned char *sha1,
const char *base, const char *path)
@@ -376,7 +716,8 @@ void diff_addremove(int addremove, unsigned mode,
memcpy(spec[0].blob_sha1, sha1, 20);
spec[0].mode = mode;
- spec[0].sha1_valid = spec[0].file_valid = 1;
+ spec[0].sha1_valid = !!memcmp(sha1, null_sha1, 20);
+ spec[0].file_valid = 1;
spec[1].file_valid = 0;
if (addremove == '+') {
@@ -384,12 +725,12 @@ void diff_addremove(int addremove, unsigned mode,
} else {
one = spec; two = one + 1;
}
-
+
if (path) {
strcpy(concatpath, base);
strcat(concatpath, path);
}
- run_external_diff(path ? concatpath : base, NULL, one, two);
+ hold_diff(path ? concatpath : base, one, two);
}
void diff_change(unsigned old_mode, unsigned new_mode,
@@ -399,17 +740,22 @@ void diff_change(unsigned old_mode, unsigned new_mode,
char concatpath[PATH_MAX];
struct diff_spec spec[2];
+ if (path) {
+ strcpy(concatpath, base);
+ strcat(concatpath, path);
+ }
+
memcpy(spec[0].blob_sha1, old_sha1, 20);
spec[0].mode = old_mode;
memcpy(spec[1].blob_sha1, new_sha1, 20);
spec[1].mode = new_mode;
- spec[0].sha1_valid = spec[0].file_valid = 1;
- spec[1].sha1_valid = spec[1].file_valid = 1;
+ spec[0].sha1_valid = !!memcmp(old_sha1, null_sha1, 20);
+ spec[1].sha1_valid = !!memcmp(new_sha1, null_sha1, 20);
+ spec[1].file_valid = spec[0].file_valid = 1;
- if (path) {
- strcpy(concatpath, base);
- strcat(concatpath, path);
- }
+ /* We do not look at changed files as candidate for
+ * rename detection ever.
+ */
run_external_diff(path ? concatpath : base, NULL, &spec[0], &spec[1]);
}