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rerere: use "struct rerere_id" instead of "char *" for conflict ID
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This gives a thin abstraction between the conflict ID that is a hash
value obtained by inspecting the conflicts and the name of the
directory under $GIT_DIR/rr-cache/, in which the previous resolution
is recorded to be replayed.  The plan is to make sure that the
presence of the directory does not imply the presense of a previous
resolution and vice-versa, and later allow us to have more than one
pair of <preimage, postimage> for a given conflict ID.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Junio C Hamano committed Jul 24, 2015
1 parent 18bb993 commit 1d51ece
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Showing 3 changed files with 85 additions and 28 deletions.
2 changes: 1 addition & 1 deletion builtin/rerere.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -103,7 +103,7 @@ int cmd_rerere(int argc, const char **argv, const char *prefix)
} else if (!strcmp(argv[0], "diff"))
for (i = 0; i < merge_rr.nr; i++) {
const char *path = merge_rr.items[i].string;
const char *id = (const char *)merge_rr.items[i].util;
const struct rerere_id *id = merge_rr.items[i].util;
diff_two(rerere_path(id, "preimage"), path, path, path);
}
else
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99 changes: 73 additions & 26 deletions rerere.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -22,17 +22,43 @@ static int rerere_autoupdate;

static char *merge_rr_path;

const char *rerere_path(const char *id, const char *file)
static void free_rerere_id(struct string_list_item *item)
{
return git_path("rr-cache/%s/%s", id, file);
free(item->util);
}

static const char *rerere_id_hex(const struct rerere_id *id)
{
return id->hex;
}

const char *rerere_path(const struct rerere_id *id, const char *file)
{
if (!file)
return git_path("rr-cache/%s", rerere_id_hex(id));

return git_path("rr-cache/%s/%s", rerere_id_hex(id), file);
}

static int has_rerere_resolution(const char *id)
static int has_rerere_resolution(const struct rerere_id *id)
{
struct stat st;

return !stat(rerere_path(id, "postimage"), &st);
}

static struct rerere_id *new_rerere_id_hex(char *hex)
{
struct rerere_id *id = xmalloc(sizeof(*id));
strcpy(id->hex, hex);
return id;
}

static struct rerere_id *new_rerere_id(unsigned char *sha1)
{
return new_rerere_id_hex(sha1_to_hex(sha1));
}

/*
* $GIT_DIR/MERGE_RR file is a collection of records, each of which is
* "conflict ID", a HT and pathname, terminated with a NUL, and is
Expand All @@ -50,6 +76,7 @@ static void read_rr(struct string_list *rr)
while (!strbuf_getwholeline(&buf, in, '\0')) {
char *path;
unsigned char sha1[20];
struct rerere_id *id;

/* There has to be the hash, tab, path and then NUL */
if (buf.len < 42 || get_sha1_hex(buf.buf, sha1))
Expand All @@ -59,8 +86,8 @@ static void read_rr(struct string_list *rr)
die("corrupt MERGE_RR");
buf.buf[40] = '\0';
path = buf.buf + 41;

string_list_insert(rr, path)->util = xstrdup(buf.buf);
id = new_rerere_id_hex(buf.buf);
string_list_insert(rr, path)->util = id;
}
strbuf_release(&buf);
fclose(in);
Expand All @@ -73,12 +100,15 @@ static int write_rr(struct string_list *rr, int out_fd)
int i;
for (i = 0; i < rr->nr; i++) {
struct strbuf buf = STRBUF_INIT;
struct rerere_id *id;

assert(rr->items[i].util != RERERE_RESOLVED);
if (!rr->items[i].util)

id = rr->items[i].util;
if (!id)
continue;
strbuf_addf(&buf, "%s\t%s%c",
(char *)rr->items[i].util,
rerere_id_hex(id),
rr->items[i].string, 0);
if (write_in_full(out_fd, buf.buf, buf.len) != buf.len)
die("unable to write rerere record");
Expand Down Expand Up @@ -530,7 +560,7 @@ int rerere_remaining(struct string_list *merge_rr)
struct string_list_item *it;
it = string_list_lookup(merge_rr, (const char *)e->name);
if (it != NULL) {
free(it->util);
free_rerere_id(it);
it->util = RERERE_RESOLVED;
}
}
Expand All @@ -548,7 +578,7 @@ int rerere_remaining(struct string_list *merge_rr)
* Returns 0 for successful replay of recorded resolution, or non-zero
* for failure.
*/
static int merge(const char *id, const char *path)
static int merge(const struct rerere_id *id, const char *path)
{
int ret;
mmfile_t cur = {NULL, 0}, base = {NULL, 0}, other = {NULL, 0};
Expand Down Expand Up @@ -582,8 +612,8 @@ static int merge(const char *id, const char *path)
*/
if (utime(rerere_path(id, "postimage"), NULL) < 0)
warning("failed utime() on %s: %s",
rerere_path(id, "postimage"),
strerror(errno));
rerere_path(id, "postimage"),
strerror(errno));

/* Update "path" with the resolution */
f = fopen(path, "w");
Expand Down Expand Up @@ -640,7 +670,7 @@ static void do_rerere_one_path(struct string_list_item *rr_item,
struct string_list *update)
{
const char *path = rr_item->string;
const char *id = (const char *)rr_item->util;
const struct rerere_id *id = rr_item->util;

/* Is there a recorded resolution we could attempt to apply? */
if (has_rerere_resolution(id)) {
Expand All @@ -660,7 +690,7 @@ static void do_rerere_one_path(struct string_list_item *rr_item,
} else {
return;
}
free(rr_item->util);
free_rerere_id(rr_item);
rr_item->util = NULL;
}

Expand All @@ -679,10 +709,10 @@ static int do_plain_rerere(struct string_list *rr, int fd)
* initial run would catch all and register their preimages.
*/
for (i = 0; i < conflict.nr; i++) {
struct rerere_id *id;
unsigned char sha1[20];
char *id;
int ret;
const char *path = conflict.items[i].string;
int ret;

if (string_list_has_string(rr, path))
continue;
Expand All @@ -695,7 +725,8 @@ static int do_plain_rerere(struct string_list *rr, int fd)
ret = handle_file(path, sha1, NULL);
if (ret < 1)
continue;
id = xstrdup(sha1_to_hex(sha1));

id = new_rerere_id(sha1);
string_list_insert(rr, path)->util = id;

/*
Expand All @@ -706,7 +737,7 @@ static int do_plain_rerere(struct string_list *rr, int fd)
* NEEDSWORK: make sure "gc" does not remove
* preimage without removing the directory.
*/
if (mkdir_in_gitdir(git_path("rr-cache/%s", id)))
if (mkdir_in_gitdir(rerere_path(id, NULL)))
continue;

/*
Expand Down Expand Up @@ -788,7 +819,7 @@ int rerere(int flags)
static int rerere_forget_one_path(const char *path, struct string_list *rr)
{
const char *filename;
char *id;
struct rerere_id *id;
unsigned char sha1[20];
int ret;
struct string_list_item *item;
Expand All @@ -802,7 +833,7 @@ static int rerere_forget_one_path(const char *path, struct string_list *rr)
return error("Could not parse conflict hunks in '%s'", path);

/* Nuke the recorded resolution for the conflict */
id = xstrdup(sha1_to_hex(sha1));
id = new_rerere_id(sha1);
filename = rerere_path(id, "postimage");
if (unlink(filename))
return (errno == ENOENT
Expand All @@ -822,7 +853,7 @@ static int rerere_forget_one_path(const char *path, struct string_list *rr)
* conflict when the user is done.
*/
item = string_list_insert(rr, path);
free(item->util);
free_rerere_id(item);
item->util = id;
fprintf(stderr, "Forgot resolution for %s\n", path);
return 0;
Expand Down Expand Up @@ -859,22 +890,38 @@ int rerere_forget(struct pathspec *pathspec)
/*
* Garbage collection support
*/
static time_t rerere_created_at(const char *id)

/*
* Note that this is not reentrant but is used only one-at-a-time
* so it does not matter right now.
*/
static struct rerere_id *dirname_to_id(const char *name)
{
static struct rerere_id id;
strcpy(id.hex, name);
return &id;
}

static time_t rerere_created_at(const char *dir_name)
{
struct stat st;
struct rerere_id *id = dirname_to_id(dir_name);

return stat(rerere_path(id, "preimage"), &st) ? (time_t) 0 : st.st_mtime;
}

static time_t rerere_last_used_at(const char *id)
static time_t rerere_last_used_at(const char *dir_name)
{
struct stat st;
struct rerere_id *id = dirname_to_id(dir_name);

return stat(rerere_path(id, "postimage"), &st) ? (time_t) 0 : st.st_mtime;
}

/*
* Remove the recorded resolution for a given conflict ID
*/
static void unlink_rr_item(const char *id)
static void unlink_rr_item(struct rerere_id *id)
{
unlink(rerere_path(id, "thisimage"));
unlink(rerere_path(id, "preimage"));
Expand All @@ -884,7 +931,7 @@ static void unlink_rr_item(const char *id)
* assume that we already have preimage recorded in
* do_plain_rerere()?
*/
rmdir(git_path("rr-cache/%s", id));
rmdir(rerere_path(id, NULL));
}

void rerere_gc(struct string_list *rr)
Expand Down Expand Up @@ -923,7 +970,7 @@ void rerere_gc(struct string_list *rr)
closedir(dir);
/* ... and then remove them one-by-one */
for (i = 0; i < to_remove.nr; i++)
unlink_rr_item(to_remove.items[i].string);
unlink_rr_item(dirname_to_id(to_remove.items[i].string));
string_list_clear(&to_remove, 0);
}

Expand All @@ -939,7 +986,7 @@ void rerere_clear(struct string_list *merge_rr)
int i;

for (i = 0; i < merge_rr->nr; i++) {
const char *id = (const char *)merge_rr->items[i].util;
struct rerere_id *id = merge_rr->items[i].util;
if (!has_rerere_resolution(id))
unlink_rr_item(id);
}
Expand Down
12 changes: 11 additions & 1 deletion rerere.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -15,9 +15,19 @@ struct pathspec;
*/
extern void *RERERE_RESOLVED;

struct rerere_id {
char hex[41];
};

extern int setup_rerere(struct string_list *, int);
extern int rerere(int);
extern const char *rerere_path(const char *id, const char *file);
/*
* Given the conflict ID and the name of a "file" used for replaying
* the recorded resolution (e.g. "preimage", "postimage"), return the
* path to that filesystem entity. With "file" specified with NULL,
* return the path to the directory that houses these files.
*/
extern const char *rerere_path(const struct rerere_id *, const char *file);
extern int rerere_forget(struct pathspec *);
extern int rerere_remaining(struct string_list *);
extern void rerere_clear(struct string_list *);
Expand Down

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