Skip to content

Commit

Permalink
Merge branch 'jc/reflog-reverse-walk'
Browse files Browse the repository at this point in the history 
An internal function used to implement "git checkout @{-1}" was
hard to use correctly.

* jc/reflog-reverse-walk:
  refs.c: fix fread error handling
  reflog: add for_each_reflog_ent_reverse() API
  for_each_recent_reflog_ent(): simplify opening of a reflog file
  for_each_reflog_ent(): extract a helper to process a single entry
  • Loading branch information
Junio C Hamano committed Mar 26, 2013
2 parents 183f880 + e4ca819 commit 6beb484
Show file tree
Hide file tree
Showing 3 changed files with 134 additions and 77 deletions.
161 changes: 115 additions & 46 deletions refs.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2332,69 +2332,138 @@ int read_ref_at(const char *refname, unsigned long at_time, int cnt,
return 1;
}

int for_each_recent_reflog_ent(const char *refname, each_reflog_ent_fn fn, long ofs, void *cb_data)
static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
{
unsigned char osha1[20], nsha1[20];
char *email_end, *message;
unsigned long timestamp;
int tz;

/* old SP new SP name <email> SP time TAB msg LF */
if (sb->len < 83 || sb->buf[sb->len - 1] != '\n' ||
get_sha1_hex(sb->buf, osha1) || sb->buf[40] != ' ' ||
get_sha1_hex(sb->buf + 41, nsha1) || sb->buf[81] != ' ' ||
!(email_end = strchr(sb->buf + 82, '>')) ||
email_end[1] != ' ' ||
!(timestamp = strtoul(email_end + 2, &message, 10)) ||
!message || message[0] != ' ' ||
(message[1] != '+' && message[1] != '-') ||
!isdigit(message[2]) || !isdigit(message[3]) ||
!isdigit(message[4]) || !isdigit(message[5]))
return 0; /* corrupt? */
email_end[1] = '\0';
tz = strtol(message + 1, NULL, 10);
if (message[6] != '\t')
message += 6;
else
message += 7;
return fn(osha1, nsha1, sb->buf + 82, timestamp, tz, message, cb_data);
}

static char *find_beginning_of_line(char *bob, char *scan)
{
while (bob < scan && *(--scan) != '\n')
; /* keep scanning backwards */
/*
* Return either beginning of the buffer, or LF at the end of
* the previous line.
*/
return scan;
}

int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data)
{
const char *logfile;
FILE *logfp;
struct strbuf sb = STRBUF_INIT;
int ret = 0;
FILE *logfp;
long pos;
int ret = 0, at_tail = 1;

logfile = git_path("logs/%s", refname);
logfp = fopen(logfile, "r");
logfp = fopen(git_path("logs/%s", refname), "r");
if (!logfp)
return -1;

if (ofs) {
struct stat statbuf;
if (fstat(fileno(logfp), &statbuf) ||
statbuf.st_size < ofs ||
fseek(logfp, -ofs, SEEK_END) ||
strbuf_getwholeline(&sb, logfp, '\n')) {
fclose(logfp);
strbuf_release(&sb);
return -1;
/* Jump to the end */
if (fseek(logfp, 0, SEEK_END) < 0)
return error("cannot seek back reflog for %s: %s",
refname, strerror(errno));
pos = ftell(logfp);
while (!ret && 0 < pos) {
int cnt;
size_t nread;
char buf[BUFSIZ];
char *endp, *scanp;

/* Fill next block from the end */
cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
if (fseek(logfp, pos - cnt, SEEK_SET))
return error("cannot seek back reflog for %s: %s",
refname, strerror(errno));
nread = fread(buf, cnt, 1, logfp);
if (nread != 1)
return error("cannot read %d bytes from reflog for %s: %s",
cnt, refname, strerror(errno));
pos -= cnt;

scanp = endp = buf + cnt;
if (at_tail && scanp[-1] == '\n')
/* Looking at the final LF at the end of the file */
scanp--;
at_tail = 0;

while (buf < scanp) {
/*
* terminating LF of the previous line, or the beginning
* of the buffer.
*/
char *bp;

bp = find_beginning_of_line(buf, scanp);

if (*bp != '\n') {
strbuf_splice(&sb, 0, 0, buf, endp - buf);
if (pos)
break; /* need to fill another block */
scanp = buf - 1; /* leave loop */
} else {
/*
* (bp + 1) thru endp is the beginning of the
* current line we have in sb
*/
strbuf_splice(&sb, 0, 0, bp + 1, endp - (bp + 1));
scanp = bp;
endp = bp + 1;
}
ret = show_one_reflog_ent(&sb, fn, cb_data);
strbuf_reset(&sb);
if (ret)
break;
}
}

while (!strbuf_getwholeline(&sb, logfp, '\n')) {
unsigned char osha1[20], nsha1[20];
char *email_end, *message;
unsigned long timestamp;
int tz;

/* old SP new SP name <email> SP time TAB msg LF */
if (sb.len < 83 || sb.buf[sb.len - 1] != '\n' ||
get_sha1_hex(sb.buf, osha1) || sb.buf[40] != ' ' ||
get_sha1_hex(sb.buf + 41, nsha1) || sb.buf[81] != ' ' ||
!(email_end = strchr(sb.buf + 82, '>')) ||
email_end[1] != ' ' ||
!(timestamp = strtoul(email_end + 2, &message, 10)) ||
!message || message[0] != ' ' ||
(message[1] != '+' && message[1] != '-') ||
!isdigit(message[2]) || !isdigit(message[3]) ||
!isdigit(message[4]) || !isdigit(message[5]))
continue; /* corrupt? */
email_end[1] = '\0';
tz = strtol(message + 1, NULL, 10);
if (message[6] != '\t')
message += 6;
else
message += 7;
ret = fn(osha1, nsha1, sb.buf + 82, timestamp, tz, message,
cb_data);
if (ret)
break;
}
if (!ret && sb.len)
ret = show_one_reflog_ent(&sb, fn, cb_data);

fclose(logfp);
strbuf_release(&sb);
return ret;
}

int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
{
return for_each_recent_reflog_ent(refname, fn, 0, cb_data);
}
FILE *logfp;
struct strbuf sb = STRBUF_INIT;
int ret = 0;

logfp = fopen(git_path("logs/%s", refname), "r");
if (!logfp)
return -1;

while (!ret && !strbuf_getwholeline(&sb, logfp, '\n'))
ret = show_one_reflog_ent(&sb, fn, cb_data);
fclose(logfp);
strbuf_release(&sb);
return ret;
}
/*
* Call fn for each reflog in the namespace indicated by name. name
* must be empty or end with '/'. Name will be used as a scratch
Expand Down
2 changes: 1 addition & 1 deletion refs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -103,7 +103,7 @@ extern int read_ref_at(const char *refname, unsigned long at_time, int cnt,
/* iterate over reflog entries */
typedef int each_reflog_ent_fn(unsigned char *osha1, unsigned char *nsha1, const char *, unsigned long, int, const char *, void *);
int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data);
int for_each_recent_reflog_ent(const char *refname, each_reflog_ent_fn fn, long, void *cb_data);
int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data);

/*
* Calls the specified function for each reflog file until it returns nonzero,
Expand Down
48 changes: 18 additions & 30 deletions sha1_name.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -856,8 +856,8 @@ static int get_sha1_oneline(const char *prefix, unsigned char *sha1,
}

struct grab_nth_branch_switch_cbdata {
long cnt, alloc;
struct strbuf *buf;
int remaining;
struct strbuf buf;
};

static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1,
Expand All @@ -867,7 +867,6 @@ static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1,
struct grab_nth_branch_switch_cbdata *cb = cb_data;
const char *match = NULL, *target = NULL;
size_t len;
int nth;

if (!prefixcmp(message, "checkout: moving from ")) {
match = message + strlen("checkout: moving from ");
Expand All @@ -876,11 +875,12 @@ static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1,

if (!match || !target)
return 0;

len = target - match;
nth = cb->cnt++ % cb->alloc;
strbuf_reset(&cb->buf[nth]);
strbuf_add(&cb->buf[nth], match, len);
if (--(cb->remaining) == 0) {
len = target - match;
strbuf_reset(&cb->buf);
strbuf_add(&cb->buf, match, len);
return 1; /* we are done */
}
return 0;
}

Expand All @@ -891,7 +891,7 @@ static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1,
static int interpret_nth_prior_checkout(const char *name, struct strbuf *buf)
{
long nth;
int i, retval;
int retval;
struct grab_nth_branch_switch_cbdata cb;
const char *brace;
char *num_end;
Expand All @@ -901,34 +901,22 @@ static int interpret_nth_prior_checkout(const char *name, struct strbuf *buf)
brace = strchr(name, '}');
if (!brace)
return -1;
nth = strtol(name+3, &num_end, 10);
nth = strtol(name + 3, &num_end, 10);
if (num_end != brace)
return -1;
if (nth <= 0)
return -1;
cb.alloc = nth;
cb.buf = xmalloc(nth * sizeof(struct strbuf));
for (i = 0; i < nth; i++)
strbuf_init(&cb.buf[i], 20);
cb.cnt = 0;
cb.remaining = nth;
strbuf_init(&cb.buf, 20);

retval = 0;
for_each_recent_reflog_ent("HEAD", grab_nth_branch_switch, 40960, &cb);
if (cb.cnt < nth) {
cb.cnt = 0;
for_each_reflog_ent("HEAD", grab_nth_branch_switch, &cb);
if (0 < for_each_reflog_ent_reverse("HEAD", grab_nth_branch_switch, &cb)) {
strbuf_reset(buf);
strbuf_add(buf, cb.buf.buf, cb.buf.len);
retval = brace - name + 1;
}
if (cb.cnt < nth)
goto release_return;
i = cb.cnt % nth;
strbuf_reset(buf);
strbuf_add(buf, cb.buf[i].buf, cb.buf[i].len);
retval = brace-name+1;

release_return:
for (i = 0; i < nth; i++)
strbuf_release(&cb.buf[i]);
free(cb.buf);

strbuf_release(&cb.buf);
return retval;
}

Expand Down

0 comments on commit 6beb484

Please sign in to comment.