Re: Tracking branch history
- From
Shawn Pearce <spearce@spearce.org>
- Date
- May 15, 2006, 09:53 UTC
- Message-ID
- <20060515095307.GB28337@spearce.org>
- In-Reply-To
- <20060515063849.GA28337@spearce.org>
Shawn Pearce <spearce@spearce.org> wrote:
Show 17 quoted lines
> Junio C Hamano <junkio@cox.net> wrote: > > Shawn Pearce <spearce@spearce.org> writes: > > > > > This is all well and good but its sort of useless without the diffcore > > > being able to lookup what SHA1 was valid on a given branch at a given > > > point in time. :-) > > > > > > I'm thinking about extending the 'extended SHA1' syntax to accept > > > a date (or date expression) as a suffix: > > > > > > HEAD@'2 hours ago' > > > HEAD@'2006-04-20' > > > HEAD@'2006-04-20 14:12' > > > > > > etc... This would be merged into get_sha1 (sha1_name.c) so its > > > usable pretty much anywhere. Does this seem reasonable? If so > > > I'll work up a patch for it.
This is a preliminary patch for this syntax. I haven't handled the absolute date parsing yet; I was hoping to use the same syntax accepted by GIT_AUTHOR_DATE/GIT_COMMITTER_DATE but looking at the code in date.c it wasn't going to be easily reused. I'll work on it more tomorrow, right now I have to go do my day job to pay the rent. :-)
Hmm... A quick look at date.c indicates I should be able to clean up this parse_date_spec function quite a bit by using code from date.c. I'll look at it more later.
-- >8 - Support 'master@2 hours ago' syntax
Extended sha1 expressions may now include date specifications which indicate a point in time within the local repository's history. If the ref indicated to the left of '@' has a log in $GIT_DIR/logs/<ref> then the value of the ref at the time indicated by the specification is obtained from the ref's log.
---
Documentation/git-rev-parse.txt | 6 ++ refs.c | 52 ++++++++++++++ refs.h | 3 + sha1_name.c | 145 ++++++++++++++++++++++++++++++++++----- 4 files changed, 189 insertions(+), 17 deletions(-)
1f16364fd8cadb6cdeb0b14a6f5439f02b578924
diff --git a/Documentation/git-rev-parse.txt b/Documentation/git-rev-parse.txt index ab896fc..df308c3 100644 --- a/Documentation/git-rev-parse.txt +++ b/Documentation/git-rev-parse.txt @@ -124,6 +124,12 @@ syntax. happen to have both heads/master and tags/master, you can explicitly say 'heads/master' to tell git which one you mean. +* A suffix '@' followed by a date specification such as 'yesterday' + (24 hours ago) or '1 month 2 weeks 3 days 1 hour 1 second ago' + to specify the value of the ref at a prior point in time. + This suffix may only be used immediately following a ref name + and the ref must have an existing log ($GIT_DIR/logs/<ref>). + * A suffix '{caret}' to a revision parameter means the first parent of that commit object. '{caret}<n>' means the <n>th parent (i.e. 'rev{caret}' diff --git a/refs.c b/refs.c index a50ea8f..da009ac 100644 --- a/refs.c +++ b/refs.c @@ -440,3 +440,55 @@ int log_ref_update(const char *ref, cons close(logfd); return 0; } + +int read_ref_at(const char *ref, unsigned long at_time, unsigned char *sha1) +{ + const char *logfile, *logdata, *rec, *c; + char *tz_c; + int logfd, tz; + struct stat st; + unsigned long date; + unsigned char oldsha1[20]; + + logfile = git_path("logs/%s", ref); + logfd = open(logfile, O_RDONLY, 0); + if (logfd < 0) + die("Unable to read log %s: %s", logfile, strerror(errno)); + fstat(logfd, &st); + if (!st.st_size) + die("Log %s is empty.", logfile); + logdata = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, logfd, 0); + close(logfd); + + rec = logdata + st.st_size; + while (logdata < rec) { + if (logdata < rec && *(rec-1) == '\n') + rec--; + while (logdata < rec && *(rec-1) != '\n') + rec--; + c = rec; + while (*c++ != '>') + /* nada */; + date = strtoul(c, NULL, 10); + if (date <= at_time) { + if (get_sha1_hex(rec, oldsha1)) + die("Log %s is corrupt.", logfile); + if (get_sha1_hex(rec + 41, sha1)) + die("Log %s is corrupt.", logfile); + munmap((void*)logdata, st.st_size); + return 0; + } + } + + c = logdata; + while (*c++ != '>') + /* nada */; + date = strtoul(c, &tz_c, 10); + tz = strtoul(tz_c, NULL, 10); + if (get_sha1_hex(logdata, sha1)) + die("Log %s is corrupt.", logfile); + munmap((void*)logdata, st.st_size); + fprintf(stderr, "warning: Log %s only goes back to %s.\n", + logfile, show_rfc2822_date(date, tz)); + return 0; +} diff --git a/refs.h b/refs.h index de3cb92..4831cdb 100644 --- a/refs.h +++ b/refs.h @@ -31,4 +31,7 @@ extern int check_ref_format(const char * /** If logging is enabled logs the change made to the ref. **/ extern int log_ref_update(const char *ref, const unsigned char *currsha1, const unsigned char *newsha1, const char *msg); +/** Reads log for the value of ref during at_time. **/ +extern int read_ref_at(const char *ref, unsigned long at_time, unsigned char *sha1); + #endif /* REFS_H */ diff --git a/sha1_name.c b/sha1_name.c index dc68355..5f33aea 100644 --- a/sha1_name.c +++ b/sha1_name.c @@ -4,6 +4,7 @@ #include "commit.h" #include "tree.h" #include "blob.h" #include "tree-walk.h" +#include "refs.h" static int find_short_object_filename(int len, const char *name, unsigned char *sha1) { @@ -234,6 +235,98 @@ static int ambiguous_path(const char *pa return slash; } +static unsigned long parse_date_spec(const char *str, int len) +{ + long delta; + time_t now; + + time(&now); + if (len == 9 && !strncasecmp("yesterday", str, 9)) + return now - 24 * 60 * 60; + if (len > 4 && !strncasecmp(" ago", str + (len - 4), 4)) { + len -= 4; + while (len) { + if (len > 2 && !strncasecmp("a ", str, 2)) { + delta = 1; + len -= 2; + str += 2; + } + else if (len > 3 && !strncasecmp("an ", str, 3)) { + delta = 1; + len -= 2; + str += 2; + } else { + delta = 0; + while (len && isdigit(*str)) { + if (delta) + delta *= 10; + delta += *str++ - '0'; + len--; + } + if (!delta) + return (time_t)-1; + while (len && isspace(*str)) { + str++; + len--; + } + } + + if (len >= 5 && !strncasecmp("month", str, 5)) { + len -= 5; + str += 5; + now -= 30 * 24 * 60 * 60 * delta; + } + else if (len >= 4 && !strncasecmp("week", str, 4)) { + len -= 4; + str += 4; + now -= 7 * 24 * 60 * 60 * delta; + } + else if (len >= 3 && !strncasecmp("day", str, 3)) { + len -= 3; + str += 3; + now -= 24 * 60 * 60 * delta; + } + else if (len >= 4 && !strncasecmp("hour", str, 4)) { + len -= 4; + str += 4; + now -= 60 * 60 * delta; + } + else if (len >= 6 && !strncasecmp("minute", str, 6)) { + len -= 6; + str += 6; + now -= 60 * delta; + } + else if (len >= 3 && !strncasecmp("min", str, 3)) { + len -= 3; + str += 3; + now -= 60 * delta; + } + else if (len >= 6 && !strncasecmp("second", str, 6)) { + len -= 6; + str += 6; + now -= delta; + } + else if (len >= 3 && !strncasecmp("sec", str, 3)) { + len -= 3; + str += 3; + now -= delta; + } + + if (len && *str == 's') { + len -= 1; + str += 1; + } + + while (len && isspace(*str)) { + str++; + len--; + } + } + return now; + } + return (time_t)-1; +} + static int get_sha1_basic(const char *str, int len, unsigned char *sha1) { static const char *fmt[] = { @@ -245,36 +338,54 @@ static int get_sha1_basic(const char *st "refs/remotes/%.*s/HEAD", NULL }; - const char **p; - const char *warning = "warning: refname '%.*s' is ambiguous.\n"; - char *pathname; - int already_found = 0; + static const char *warning = "warning: refname '%.*s' is ambiguous.\n"; + const char **p, *pathname; + char *real_path = NULL; + int refs_found = 0, at_mark; + unsigned long at_time = (unsigned long)-1; unsigned char *this_result; unsigned char sha1_from_ref[20]; if (len == 40 && !get_sha1_hex(str, sha1)) return 0; + /* At a given period of time? "@2 hours ago" */ + for (at_mark = 1; at_mark < len; at_mark++) { + if (str[at_mark] == '@') { + at_time = parse_date_spec(str + at_mark + 1, len - at_mark - 1); + if (at_time == (unsigned long)-1) + die("Invalid date spec after @ in '%.*s'", len, str); + len = at_mark; + } + } + /* Accept only unambiguous ref paths. */ if (ambiguous_path(str, len)) return -1; for (p = fmt; *p; p++) { - this_result = already_found ? sha1_from_ref : sha1; - pathname = git_path(*p, len, str); - if (!read_ref(pathname, this_result)) { - if (warn_ambiguous_refs) { - if (already_found) - fprintf(stderr, warning, len, str); - already_found++; - } - else - return 0; + this_result = refs_found ? sha1_from_ref : sha1; + pathname = resolve_ref(git_path(*p, len, str), this_result, 1); + if (pathname) { + if (!refs_found++) + real_path = strdup(pathname); + if (!warn_ambiguous_refs) + break; } } - if (already_found) - return 0; - return -1; + + if (!refs_found) + return -1; + + if (warn_ambiguous_refs && refs_found > 1) + fprintf(stderr, warning, len, str); + + if (at_time != (unsigned long)-1) { + read_ref_at(real_path + strlen(git_path(".")) - 1, at_time, sha1); + } + + free(real_path); + return 0; } static int get_sha1_1(const char *name, int len, unsigned char *sha1);
-- 1.3.2.g7278