user-manual: start revising "internals" chapter
[gitweb.git] / sha1_name.c
index cd85d1fa0f9f2afb4e159cb635db435e75ef3e58..bede0e5b0659db31a1dfdaab3d17627199150ea7 100644 (file)
@@ -76,15 +76,15 @@ static int find_short_packed_object(int len, const unsigned char *match, unsigne
 
        prepare_packed_git();
        for (p = packed_git; p && found < 2; p = p->next) {
-               unsigned num = num_packed_objects(p);
-               unsigned first = 0, last = num;
+               uint32_t num = num_packed_objects(p);
+               uint32_t first = 0, last = num;
                while (first < last) {
-                       unsigned mid = (first + last) / 2;
+                       uint32_t mid = (first + last) / 2;
                        unsigned char now[20];
                        int cmp;
 
                        nth_packed_object_sha1(p, mid, now);
-                       cmp = memcmp(match, now, 20);
+                       cmp = hashcmp(match, now);
                        if (!cmp) {
                                first = mid;
                                break;
@@ -103,10 +103,10 @@ static int find_short_packed_object(int len, const unsigned char *match, unsigne
                                    !match_sha(len, match, next)) {
                                        /* unique within this pack */
                                        if (!found) {
-                                               memcpy(found_sha1, now, 20);
+                                               hashcpy(found_sha1, now);
                                                found++;
                                        }
-                                       else if (memcmp(found_sha1, now, 20)) {
+                                       else if (hashcmp(found_sha1, now)) {
                                                found = 2;
                                                break;
                                        }
@@ -120,7 +120,7 @@ static int find_short_packed_object(int len, const unsigned char *match, unsigne
                }
        }
        if (found == 1)
-               memcpy(sha1, found_sha1, 20);
+               hashcpy(sha1, found_sha1);
        return found;
 }
 
@@ -140,13 +140,13 @@ static int find_unique_short_object(int len, char *canonical,
        if (1 < has_unpacked || 1 < has_packed)
                return SHORT_NAME_AMBIGUOUS;
        if (has_unpacked != has_packed) {
-               memcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1), 20);
+               hashcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1));
                return 0;
        }
        /* Both have unique ones -- do they match? */
-       if (memcmp(packed_sha1, unpacked_sha1, 20))
+       if (hashcmp(packed_sha1, unpacked_sha1))
                return SHORT_NAME_AMBIGUOUS;
-       memcpy(sha1, packed_sha1, 20);
+       hashcpy(sha1, packed_sha1);
        return 0;
 }
 
@@ -157,9 +157,9 @@ static int get_short_sha1(const char *name, int len, unsigned char *sha1,
        char canonical[40];
        unsigned char res[20];
 
-       if (len < MINIMUM_ABBREV)
+       if (len < MINIMUM_ABBREV || len > 40)
                return -1;
-       memset(res, 0, 20);
+       hashclr(res);
        memset(canonical, 'x', 40);
        for (i = 0; i < len ;i++) {
                unsigned char c = name[i];
@@ -191,9 +191,9 @@ const char *find_unique_abbrev(const unsigned char *sha1, int len)
        int status, is_null;
        static char hex[41];
 
-       is_null = !memcmp(sha1, null_sha1, 20);
+       is_null = is_null_sha1(sha1);
        memcpy(hex, sha1_to_hex(sha1), 40);
-       if (len == 40)
+       if (len == 40 || !len)
                return hex;
        while (len < 40) {
                unsigned char sha1_ret[20];
@@ -235,55 +235,106 @@ static int ambiguous_path(const char *path, int len)
        return slash;
 }
 
+static const char *ref_fmt[] = {
+       "%.*s",
+       "refs/%.*s",
+       "refs/tags/%.*s",
+       "refs/heads/%.*s",
+       "refs/remotes/%.*s",
+       "refs/remotes/%.*s/HEAD",
+       NULL
+};
+
+int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
+{
+       const char **p, *r;
+       int refs_found = 0;
+
+       *ref = NULL;
+       for (p = ref_fmt; *p; p++) {
+               unsigned char sha1_from_ref[20];
+               unsigned char *this_result;
+
+               this_result = refs_found ? sha1_from_ref : sha1;
+               r = resolve_ref(mkpath(*p, len, str), this_result, 1, NULL);
+               if (r) {
+                       if (!refs_found++)
+                               *ref = xstrdup(r);
+                       if (!warn_ambiguous_refs)
+                               break;
+               }
+       }
+       return refs_found;
+}
+
+int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
+{
+       const char **p;
+       int logs_found = 0;
+
+       *log = NULL;
+       for (p = ref_fmt; *p; p++) {
+               struct stat st;
+               unsigned char hash[20];
+               char path[PATH_MAX];
+               const char *ref, *it;
+
+               strcpy(path, mkpath(*p, len, str));
+               ref = resolve_ref(path, hash, 0, NULL);
+               if (!ref)
+                       continue;
+               if (!stat(git_path("logs/%s", path), &st) &&
+                   S_ISREG(st.st_mode))
+                       it = path;
+               else if (strcmp(ref, path) &&
+                        !stat(git_path("logs/%s", ref), &st) &&
+                        S_ISREG(st.st_mode))
+                       it = ref;
+               else
+                       continue;
+               if (!logs_found++) {
+                       *log = xstrdup(it);
+                       hashcpy(sha1, hash);
+               }
+               if (!warn_ambiguous_refs)
+                       break;
+       }
+       return logs_found;
+}
+
 static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 {
-       static const char *fmt[] = {
-               "%.*s",
-               "refs/%.*s",
-               "refs/tags/%.*s",
-               "refs/heads/%.*s",
-               "refs/remotes/%.*s",
-               "refs/remotes/%.*s/HEAD",
-               NULL
-       };
        static const char *warning = "warning: refname '%.*s' is ambiguous.\n";
-       const char **p, *pathname;
-       char *real_path = NULL;
-       int refs_found = 0, am;
-       unsigned long at_time = (unsigned long)-1;
-       unsigned char *this_result;
-       unsigned char sha1_from_ref[20];
+       char *real_ref = NULL;
+       int refs_found = 0;
+       int at, reflog_len;
 
        if (len == 40 && !get_sha1_hex(str, sha1))
                return 0;
 
-       /* At a given period of time? "@{2 hours ago}" */
-       for (am = 1; am < len - 1; am++) {
-               if (str[am] == '@' && str[am+1] == '{' && str[len-1] == '}') {
-                       int date_len = len - am - 3;
-                       char *date_spec = xmalloc(date_len + 1);
-                       safe_strncpy(date_spec, str + am + 2, date_len + 1);
-                       at_time = approxidate(date_spec);
-                       free(date_spec);
-                       len = am;
-                       break;
+       /* basic@{time or number} format to query ref-log */
+       reflog_len = at = 0;
+       if (str[len-1] == '}') {
+               for (at = 0; at < len - 1; at++) {
+                       if (str[at] == '@' && str[at+1] == '{') {
+                               reflog_len = (len-1) - (at+2);
+                               len = at;
+                               break;
+                       }
                }
        }
 
        /* Accept only unambiguous ref paths. */
-       if (ambiguous_path(str, len))
+       if (len && ambiguous_path(str, len))
                return -1;
 
-       for (p = fmt; *p; p++) {
-               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 (!len && reflog_len) {
+               /* allow "@{...}" to mean the current branch reflog */
+               refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);
+       } else if (reflog_len)
+               refs_found = dwim_log(str, len, sha1, &real_ref);
+       else
+               refs_found = dwim_ref(str, len, sha1, &real_ref);
 
        if (!refs_found)
                return -1;
@@ -291,14 +342,39 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
        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);
+       if (reflog_len) {
+               int nth, i;
+               unsigned long at_time;
+               unsigned long co_time;
+               int co_tz, co_cnt;
+
+               /* Is it asking for N-th entry, or approxidate? */
+               for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
+                       char ch = str[at+2+i];
+                       if ('0' <= ch && ch <= '9')
+                               nth = nth * 10 + ch - '0';
+                       else
+                               nth = -1;
+               }
+               if (0 <= nth)
+                       at_time = 0;
+               else
+                       at_time = approxidate(str + at + 2);
+               if (read_ref_at(real_ref, at_time, nth, sha1, NULL,
+                               &co_time, &co_tz, &co_cnt)) {
+                       if (at_time)
+                               fprintf(stderr,
+                                       "warning: Log for '%.*s' only goes "
+                                       "back to %s.\n", len, str,
+                                       show_rfc2822_date(co_time, co_tz));
+                       else
+                               fprintf(stderr,
+                                       "warning: Log for '%.*s' only has "
+                                       "%d entries.\n", len, str, co_cnt);
+               }
        }
 
-       free(real_path);
+       free(real_ref);
        return 0;
 }
 
@@ -320,13 +396,13 @@ static int get_parent(const char *name, int len,
        if (parse_commit(commit))
                return -1;
        if (!idx) {
-               memcpy(result, commit->object.sha1, 20);
+               hashcpy(result, commit->object.sha1);
                return 0;
        }
        p = commit->parents;
        while (p) {
                if (!--idx) {
-                       memcpy(result, p->item->object.sha1, 20);
+                       hashcpy(result, p->item->object.sha1);
                        return 0;
                }
                p = p->next;
@@ -347,9 +423,9 @@ static int get_nth_ancestor(const char *name, int len,
 
                if (!commit || parse_commit(commit) || !commit->parents)
                        return -1;
-               memcpy(sha1, commit->parents->item->object.sha1, 20);
+               hashcpy(sha1, commit->parents->item->object.sha1);
        }
-       memcpy(result, sha1, 20);
+       hashcpy(result, sha1);
        return 0;
 }
 
@@ -381,13 +457,13 @@ static int peel_onion(const char *name, int len, unsigned char *sha1)
 
        sp++; /* beginning of type name, or closing brace for empty */
        if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
-               expected_type = TYPE_COMMIT;
+               expected_type = OBJ_COMMIT;
        else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
-               expected_type = TYPE_TREE;
+               expected_type = OBJ_TREE;
        else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
-               expected_type = TYPE_BLOB;
+               expected_type = OBJ_BLOB;
        else if (sp[0] == '}')
-               expected_type = TYPE_NONE;
+               expected_type = OBJ_NONE;
        else
                return -1;
 
@@ -401,7 +477,7 @@ static int peel_onion(const char *name, int len, unsigned char *sha1)
                o = deref_tag(o, name, sp - name - 2);
                if (!o || (!o->parsed && !parse_object(o->sha1)))
                        return -1;
-               memcpy(sha1, o->sha1, 20);
+               hashcpy(sha1, o->sha1);
        }
        else {
                /* At this point, the syntax look correct, so
@@ -413,12 +489,12 @@ static int peel_onion(const char *name, int len, unsigned char *sha1)
                        if (!o || (!o->parsed && !parse_object(o->sha1)))
                                return -1;
                        if (o->type == expected_type) {
-                               memcpy(sha1, o->sha1, 20);
+                               hashcpy(sha1, o->sha1);
                                return 0;
                        }
-                       if (o->type == TYPE_TAG)
+                       if (o->type == OBJ_TAG)
                                o = ((struct tag*) o)->tagged;
-                       else if (o->type == TYPE_COMMIT)
+                       else if (o->type == OBJ_COMMIT)
                                o = &(((struct commit *) o)->tree->object);
                        else
                                return error("%.*s: expected %s type, but the object dereferences to %s type",
@@ -431,6 +507,26 @@ static int peel_onion(const char *name, int len, unsigned char *sha1)
        return 0;
 }
 
+static int get_describe_name(const char *name, int len, unsigned char *sha1)
+{
+       const char *cp;
+
+       for (cp = name + len - 1; name + 2 <= cp; cp--) {
+               char ch = *cp;
+               if (hexval(ch) & ~0377) {
+                       /* We must be looking at g in "SOMETHING-g"
+                        * for it to be describe output.
+                        */
+                       if (ch == 'g' && cp[-1] == '-') {
+                               cp++;
+                               len -= cp - name;
+                               return get_short_sha1(cp, len, sha1, 1);
+                       }
+               }
+       }
+       return -1;
+}
+
 static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 {
        int ret, has_suffix;
@@ -472,9 +568,75 @@ static int get_sha1_1(const char *name, int len, unsigned char *sha1)
        ret = get_sha1_basic(name, len, sha1);
        if (!ret)
                return 0;
+
+       /* It could be describe output that is "SOMETHING-gXXXX" */
+       ret = get_describe_name(name, len, sha1);
+       if (!ret)
+               return 0;
+
        return get_short_sha1(name, len, sha1, 0);
 }
 
+static int handle_one_ref(const char *path,
+               const unsigned char *sha1, int flag, void *cb_data)
+{
+       struct commit_list **list = cb_data;
+       struct object *object = parse_object(sha1);
+       if (!object)
+               return 0;
+       if (object->type == OBJ_TAG)
+               object = deref_tag(object, path, strlen(path));
+       if (object->type != OBJ_COMMIT)
+               return 0;
+       insert_by_date((struct commit *)object, list);
+       return 0;
+}
+
+/*
+ * This interprets names like ':/Initial revision of "git"' by searching
+ * through history and returning the first commit whose message starts
+ * with the given string.
+ *
+ * For future extension, ':/!' is reserved. If you want to match a message
+ * beginning with a '!', you have to repeat the exclamation mark.
+ */
+
+#define ONELINE_SEEN (1u<<20)
+static int get_sha1_oneline(const char *prefix, unsigned char *sha1)
+{
+       struct commit_list *list = NULL, *backup = NULL, *l;
+       int retval = -1;
+
+       if (prefix[0] == '!') {
+               if (prefix[1] != '!')
+                       die ("Invalid search pattern: %s", prefix);
+               prefix++;
+       }
+       if (!save_commit_buffer)
+               return error("Could not expand oneline-name.");
+       for_each_ref(handle_one_ref, &list);
+       for (l = list; l; l = l->next)
+               commit_list_insert(l->item, &backup);
+       while (list) {
+               char *p;
+               struct commit *commit;
+
+               commit = pop_most_recent_commit(&list, ONELINE_SEEN);
+               parse_object(commit->object.sha1);
+               if (!commit->buffer || !(p = strstr(commit->buffer, "\n\n")))
+                       continue;
+               if (!prefixcmp(p + 2, prefix)) {
+                       hashcpy(sha1, commit->object.sha1);
+                       retval = 0;
+                       break;
+               }
+       }
+       free_commit_list(list);
+       for (l = backup; l; l = l->next)
+               clear_commit_marks(l->item, ONELINE_SEEN);
+       return retval;
+}
+
 /*
  * This is like "get_sha1_basic()", except it allows "sha1 expressions",
  * notably "xyz^" for "parent of xyz"
@@ -498,6 +660,8 @@ int get_sha1(const char *name, unsigned char *sha1)
                int stage = 0;
                struct cache_entry *ce;
                int pos;
+               if (namelen > 2 && name[1] == '/')
+                       return get_sha1_oneline(name + 2, sha1);
                if (namelen < 3 ||
                    name[2] != ':' ||
                    name[1] < '0' || '3' < name[1])
@@ -520,7 +684,7 @@ int get_sha1(const char *name, unsigned char *sha1)
                            memcmp(ce->name, cp, namelen))
                                break;
                        if (ce_stage(ce) == stage) {
-                               memcpy(sha1, ce->sha1, 20);
+                               hashcpy(sha1, ce->sha1);
                                return 0;
                        }
                        pos++;