Update packedGit config option documentation.
[gitweb.git] / commit.c
index 0bbfa2ab31917e2a7584b0267c04f3324fad28d9..afdf27eeceb76f4f3842ba09b48d07bc218846d6 100644 (file)
--- a/commit.c
+++ b/commit.c
@@ -1,75 +1,99 @@
-#include <ctype.h>
+#include "cache.h"
 #include "tag.h"
 #include "commit.h"
-#include "cache.h"
+#include "pkt-line.h"
+#include "utf8.h"
+
+int save_commit_buffer = 1;
 
 struct sort_node
 {
        /*
-         * the number of children of the associated commit
-         * that also occur in the list being sorted.
-         */
+        * the number of children of the associated commit
+        * that also occur in the list being sorted.
+        */
        unsigned int indegree;
 
        /*
-         * reference to original list item that we will re-use
-         * on output.
-         */
+        * reference to original list item that we will re-use
+        * on output.
+        */
        struct commit_list * list_item;
 
 };
 
 const char *commit_type = "commit";
 
+struct cmt_fmt_map {
+       const char *n;
+       size_t cmp_len;
+       enum cmit_fmt v;
+} cmt_fmts[] = {
+       { "raw",        1,      CMIT_FMT_RAW },
+       { "medium",     1,      CMIT_FMT_MEDIUM },
+       { "short",      1,      CMIT_FMT_SHORT },
+       { "email",      1,      CMIT_FMT_EMAIL },
+       { "full",       5,      CMIT_FMT_FULL },
+       { "fuller",     5,      CMIT_FMT_FULLER },
+       { "oneline",    1,      CMIT_FMT_ONELINE },
+};
+
 enum cmit_fmt get_commit_format(const char *arg)
 {
-       if (!*arg)
+       int i;
+
+       if (!arg || !*arg)
                return CMIT_FMT_DEFAULT;
-       if (!strcmp(arg, "=raw"))
-               return CMIT_FMT_RAW;
-       if (!strcmp(arg, "=medium"))
-               return CMIT_FMT_MEDIUM;
-       if (!strcmp(arg, "=short"))
-               return CMIT_FMT_SHORT;
-       if (!strcmp(arg, "=full"))
-               return CMIT_FMT_FULL;
-       die("invalid --pretty format");
-}
-
-static struct commit *check_commit(struct object *obj, const unsigned char *sha1)
-{
-       if (obj->type != commit_type) {
-               error("Object %s is a %s, not a commit", 
-                     sha1_to_hex(sha1), obj->type);
+       if (*arg == '=')
+               arg++;
+       for (i = 0; i < ARRAY_SIZE(cmt_fmts); i++) {
+               if (!strncmp(arg, cmt_fmts[i].n, cmt_fmts[i].cmp_len))
+                       return cmt_fmts[i].v;
+       }
+
+       die("invalid --pretty format: %s", arg);
+}
+
+static struct commit *check_commit(struct object *obj,
+                                  const unsigned char *sha1,
+                                  int quiet)
+{
+       if (obj->type != OBJ_COMMIT) {
+               if (!quiet)
+                       error("Object %s is a %s, not a commit",
+                             sha1_to_hex(sha1), typename(obj->type));
                return NULL;
        }
        return (struct commit *) obj;
 }
 
-struct commit *lookup_commit_reference(const unsigned char *sha1)
+struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
+                                             int quiet)
 {
-       struct object *obj = parse_object(sha1);
+       struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
 
        if (!obj)
                return NULL;
-       if (obj->type == tag_type)
-               obj = ((struct tag *)obj)->tagged;
-       return check_commit(obj, sha1);
+       return check_commit(obj, sha1, quiet);
+}
+
+struct commit *lookup_commit_reference(const unsigned char *sha1)
+{
+       return lookup_commit_reference_gently(sha1, 0);
 }
 
 struct commit *lookup_commit(const unsigned char *sha1)
 {
        struct object *obj = lookup_object(sha1);
        if (!obj) {
-               struct commit *ret = xmalloc(sizeof(struct commit));
-               memset(ret, 0, sizeof(struct commit));
+               struct commit *ret = alloc_commit_node();
                created_object(sha1, &ret->object);
-               ret->object.type = commit_type;
+               ret->object.type = OBJ_COMMIT;
                return ret;
        }
        if (!obj->type)
-               obj->type = commit_type;
-       return check_commit(obj, sha1);
+               obj->type = OBJ_COMMIT;
+       return check_commit(obj, sha1, 0);
 }
 
 static unsigned long parse_commit_date(const char *buf)
@@ -90,31 +114,226 @@ static unsigned long parse_commit_date(const char *buf)
        return date;
 }
 
+static struct commit_graft **commit_graft;
+static int commit_graft_alloc, commit_graft_nr;
+
+static int commit_graft_pos(const unsigned char *sha1)
+{
+       int lo, hi;
+       lo = 0;
+       hi = commit_graft_nr;
+       while (lo < hi) {
+               int mi = (lo + hi) / 2;
+               struct commit_graft *graft = commit_graft[mi];
+               int cmp = hashcmp(sha1, graft->sha1);
+               if (!cmp)
+                       return mi;
+               if (cmp < 0)
+                       hi = mi;
+               else
+                       lo = mi + 1;
+       }
+       return -lo - 1;
+}
+
+int register_commit_graft(struct commit_graft *graft, int ignore_dups)
+{
+       int pos = commit_graft_pos(graft->sha1);
+       
+       if (0 <= pos) {
+               if (ignore_dups)
+                       free(graft);
+               else {
+                       free(commit_graft[pos]);
+                       commit_graft[pos] = graft;
+               }
+               return 1;
+       }
+       pos = -pos - 1;
+       if (commit_graft_alloc <= ++commit_graft_nr) {
+               commit_graft_alloc = alloc_nr(commit_graft_alloc);
+               commit_graft = xrealloc(commit_graft,
+                                       sizeof(*commit_graft) *
+                                       commit_graft_alloc);
+       }
+       if (pos < commit_graft_nr)
+               memmove(commit_graft + pos + 1,
+                       commit_graft + pos,
+                       (commit_graft_nr - pos - 1) *
+                       sizeof(*commit_graft));
+       commit_graft[pos] = graft;
+       return 0;
+}
+
+struct commit_graft *read_graft_line(char *buf, int len)
+{
+       /* The format is just "Commit Parent1 Parent2 ...\n" */
+       int i;
+       struct commit_graft *graft = NULL;
+
+       if (buf[len-1] == '\n')
+               buf[--len] = 0;
+       if (buf[0] == '#' || buf[0] == '\0')
+               return NULL;
+       if ((len + 1) % 41) {
+       bad_graft_data:
+               error("bad graft data: %s", buf);
+               free(graft);
+               return NULL;
+       }
+       i = (len + 1) / 41 - 1;
+       graft = xmalloc(sizeof(*graft) + 20 * i);
+       graft->nr_parent = i;
+       if (get_sha1_hex(buf, graft->sha1))
+               goto bad_graft_data;
+       for (i = 40; i < len; i += 41) {
+               if (buf[i] != ' ')
+                       goto bad_graft_data;
+               if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
+                       goto bad_graft_data;
+       }
+       return graft;
+}
+
+int read_graft_file(const char *graft_file)
+{
+       FILE *fp = fopen(graft_file, "r");
+       char buf[1024];
+       if (!fp)
+               return -1;
+       while (fgets(buf, sizeof(buf), fp)) {
+               /* The format is just "Commit Parent1 Parent2 ...\n" */
+               int len = strlen(buf);
+               struct commit_graft *graft = read_graft_line(buf, len);
+               if (!graft)
+                       continue;
+               if (register_commit_graft(graft, 1))
+                       error("duplicate graft data: %s", buf);
+       }
+       fclose(fp);
+       return 0;
+}
+
+static void prepare_commit_graft(void)
+{
+       static int commit_graft_prepared;
+       char *graft_file;
+
+       if (commit_graft_prepared)
+               return;
+       graft_file = get_graft_file();
+       read_graft_file(graft_file);
+       /* make sure shallows are read */
+       is_repository_shallow();
+       commit_graft_prepared = 1;
+}
+
+static struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
+{
+       int pos;
+       prepare_commit_graft();
+       pos = commit_graft_pos(sha1);
+       if (pos < 0)
+               return NULL;
+       return commit_graft[pos];
+}
+
+int write_shallow_commits(int fd, int use_pack_protocol)
+{
+       int i, count = 0;
+       for (i = 0; i < commit_graft_nr; i++)
+               if (commit_graft[i]->nr_parent < 0) {
+                       const char *hex =
+                               sha1_to_hex(commit_graft[i]->sha1);
+                       count++;
+                       if (use_pack_protocol)
+                               packet_write(fd, "shallow %s", hex);
+                       else {
+                               write(fd, hex,  40);
+                               write(fd, "\n", 1);
+                       }
+               }
+       return count;
+}
+
+int unregister_shallow(const unsigned char *sha1)
+{
+       int pos = commit_graft_pos(sha1);
+       if (pos < 0)
+               return -1;
+       if (pos + 1 < commit_graft_nr)
+               memcpy(commit_graft + pos, commit_graft + pos + 1,
+                               sizeof(struct commit_graft *)
+                               * (commit_graft_nr - pos - 1));
+       commit_graft_nr--;
+       return 0;
+}
+
 int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
 {
-       void *bufptr = buffer;
+       char *tail = buffer;
+       char *bufptr = buffer;
        unsigned char parent[20];
        struct commit_list **pptr;
+       struct commit_graft *graft;
+       unsigned n_refs = 0;
 
        if (item->object.parsed)
                return 0;
        item->object.parsed = 1;
-       get_sha1_hex(bufptr + 5, parent);
+       tail += size;
+       if (tail <= bufptr + 5 || memcmp(bufptr, "tree ", 5))
+               return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
+       if (tail <= bufptr + 45 || get_sha1_hex(bufptr + 5, parent) < 0)
+               return error("bad tree pointer in commit %s",
+                            sha1_to_hex(item->object.sha1));
        item->tree = lookup_tree(parent);
        if (item->tree)
-               add_ref(&item->object, &item->tree->object);
+               n_refs++;
        bufptr += 46; /* "tree " + "hex sha1" + "\n" */
        pptr = &item->parents;
-       while (!memcmp(bufptr, "parent ", 7) &&
-              !get_sha1_hex(bufptr + 7, parent)) {
-               struct commit *new_parent = lookup_commit(parent);
+
+       graft = lookup_commit_graft(item->object.sha1);
+       while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
+               struct commit *new_parent;
+
+               if (tail <= bufptr + 48 ||
+                   get_sha1_hex(bufptr + 7, parent) ||
+                   bufptr[47] != '\n')
+                       return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
+               bufptr += 48;
+               if (graft)
+                       continue;
+               new_parent = lookup_commit(parent);
                if (new_parent) {
                        pptr = &commit_list_insert(new_parent, pptr)->next;
-                       add_ref(&item->object, &new_parent->object);
+                       n_refs++;
+               }
+       }
+       if (graft) {
+               int i;
+               struct commit *new_parent;
+               for (i = 0; i < graft->nr_parent; i++) {
+                       new_parent = lookup_commit(graft->parent[i]);
+                       if (!new_parent)
+                               continue;
+                       pptr = &commit_list_insert(new_parent, pptr)->next;
+                       n_refs++;
                }
-               bufptr += 48;
        }
        item->date = parse_commit_date(bufptr);
+
+       if (track_object_refs) {
+               unsigned i = 0;
+               struct commit_list *p;
+               struct object_refs *refs = alloc_object_refs(n_refs);
+               if (item->tree)
+                       refs->ref[i++] = &item->tree->object;
+               for (p = item->parents; p; p = p->next)
+                       refs->ref[i++] = &p->item->object;
+               set_object_refs(&item->object, refs);
+       }
+
        return 0;
 }
 
@@ -137,7 +356,7 @@ int parse_commit(struct commit *item)
                             sha1_to_hex(item->object.sha1));
        }
        ret = parse_commit_buffer(item, buffer, size);
-       if (!ret) {
+       if (save_commit_buffer && !ret) {
                item->buffer = buffer;
                return 0;
        }
@@ -209,6 +428,22 @@ struct commit *pop_most_recent_commit(struct commit_list **list,
        return ret;
 }
 
+void clear_commit_marks(struct commit *commit, unsigned int mark)
+{
+       struct commit_list *parents;
+
+       commit->object.flags &= ~mark;
+       parents = commit->parents;
+       while (parents) {
+               struct commit *parent = parents->item;
+
+               /* Have we already cleared this? */
+               if (mark & parent->object.flags)
+                       clear_commit_marks(parent, mark);
+               parents = parents->next;
+       }
+}
+
 /*
  * Generic support for pretty-printing the header
  */
@@ -218,22 +453,66 @@ static int get_one_line(const char *msg, unsigned long len)
 
        while (len--) {
                char c = *msg++;
+               if (!c)
+                       break;
                ret++;
                if (c == '\n')
                        break;
-               if (!c)
-                       return 0;
        }
        return ret;
 }
 
-static int add_user_info(const char *what, enum cmit_fmt fmt, char *buf, const char *line)
+static int is_rfc2047_special(char ch)
+{
+       return ((ch & 0x80) || (ch == '=') || (ch == '?') || (ch == '_'));
+}
+
+static int add_rfc2047(char *buf, const char *line, int len)
+{
+       char *bp = buf;
+       int i, needquote;
+       static const char q_utf8[] = "=?utf-8?q?";
+
+       for (i = needquote = 0; !needquote && i < len; i++) {
+               unsigned ch = line[i];
+               if (ch & 0x80)
+                       needquote++;
+               if ((i + 1 < len) &&
+                   (ch == '=' && line[i+1] == '?'))
+                       needquote++;
+       }
+       if (!needquote)
+               return sprintf(buf, "%.*s", len, line);
+
+       memcpy(bp, q_utf8, sizeof(q_utf8)-1);
+       bp += sizeof(q_utf8)-1;
+       for (i = 0; i < len; i++) {
+               unsigned ch = line[i] & 0xFF;
+               if (is_rfc2047_special(ch)) {
+                       sprintf(bp, "=%02X", ch);
+                       bp += 3;
+               }
+               else if (ch == ' ')
+                       *bp++ = '_';
+               else
+                       *bp++ = ch;
+       }
+       memcpy(bp, "?=", 2);
+       bp += 2;
+       return bp - buf;
+}
+
+static int add_user_info(const char *what, enum cmit_fmt fmt, char *buf,
+                        const char *line, int relative_date)
 {
        char *date;
-       unsigned int namelen;
+       int namelen;
        unsigned long time;
        int tz, ret;
+       const char *filler = "    ";
 
+       if (fmt == CMIT_FMT_ONELINE)
+               return 0;
        date = strchr(line, '>');
        if (!date)
                return 0;
@@ -241,42 +520,226 @@ static int add_user_info(const char *what, enum cmit_fmt fmt, char *buf, const c
        time = strtoul(date, &date, 10);
        tz = strtol(date, NULL, 10);
 
-       ret = sprintf(buf, "%s: %.*s\n", what, namelen, line);
-       if (fmt == CMIT_FMT_MEDIUM)
-               ret += sprintf(buf + ret, "Date:   %s\n", show_date(time, tz));
+       if (fmt == CMIT_FMT_EMAIL) {
+               char *name_tail = strchr(line, '<');
+               int display_name_length;
+               if (!name_tail)
+                       return 0;
+               while (line < name_tail && isspace(name_tail[-1]))
+                       name_tail--;
+               display_name_length = name_tail - line;
+               filler = "";
+               strcpy(buf, "From: ");
+               ret = strlen(buf);
+               ret += add_rfc2047(buf + ret, line, display_name_length);
+               memcpy(buf + ret, name_tail, namelen - display_name_length);
+               ret += namelen - display_name_length;
+               buf[ret++] = '\n';
+       }
+       else {
+               ret = sprintf(buf, "%s: %.*s%.*s\n", what,
+                             (fmt == CMIT_FMT_FULLER) ? 4 : 0,
+                             filler, namelen, line);
+       }
+       switch (fmt) {
+       case CMIT_FMT_MEDIUM:
+               ret += sprintf(buf + ret, "Date:   %s\n",
+                              show_date(time, tz, relative_date));
+               break;
+       case CMIT_FMT_EMAIL:
+               ret += sprintf(buf + ret, "Date: %s\n",
+                              show_rfc2822_date(time, tz));
+               break;
+       case CMIT_FMT_FULLER:
+               ret += sprintf(buf + ret, "%sDate: %s\n", what,
+                              show_date(time, tz, relative_date));
+               break;
+       default:
+               /* notin' */
+               break;
+       }
        return ret;
 }
 
-static int is_empty_line(const char *line, int len)
+static int is_empty_line(const char *line, int *len_p)
 {
+       int len = *len_p;
        while (len && isspace(line[len-1]))
                len--;
+       *len_p = len;
        return !len;
 }
 
-static int add_parent_info(enum cmit_fmt fmt, char *buf, const char *line, int parents)
+static int add_merge_info(enum cmit_fmt fmt, char *buf, const struct commit *commit, int abbrev)
 {
-       int offset = 0;
-       switch (parents) {
-       case 1:
-               break;
-       case 2:
-               /* Go back to the previous line: 40 characters of previous parent, and one '\n' */
-               offset = sprintf(buf, "Merge: %.40s\n", line-41);
-               /* Fallthrough */
-       default:
-               /* Replace the previous '\n' with a space */
-               buf[offset-1] = ' ';
-               offset += sprintf(buf + offset, "%.40s\n", line+7);
+       struct commit_list *parent = commit->parents;
+       int offset;
+
+       if ((fmt == CMIT_FMT_ONELINE) || (fmt == CMIT_FMT_EMAIL) ||
+           !parent || !parent->next)
+               return 0;
+
+       offset = sprintf(buf, "Merge:");
+
+       while (parent) {
+               struct commit *p = parent->item;
+               const char *hex = NULL;
+               const char *dots;
+               if (abbrev)
+                       hex = find_unique_abbrev(p->object.sha1, abbrev);
+               if (!hex)
+                       hex = sha1_to_hex(p->object.sha1);
+               dots = (abbrev && strlen(hex) != 40) ?  "..." : "";
+               parent = parent->next;
+
+               offset += sprintf(buf + offset, " %s%s", hex, dots);
        }
+       buf[offset++] = '\n';
        return offset;
 }
 
-unsigned long pretty_print_commit(enum cmit_fmt fmt, const char *msg, unsigned long len, char *buf, unsigned long space)
+static char *get_header(const struct commit *commit, const char *key)
+{
+       int key_len = strlen(key);
+       const char *line = commit->buffer;
+
+       for (;;) {
+               const char *eol = strchr(line, '\n'), *next;
+
+               if (line == eol)
+                       return NULL;
+               if (!eol) {
+                       eol = line + strlen(line);
+                       next = NULL;
+               } else
+                       next = eol + 1;
+               if (!strncmp(line, key, key_len) && line[key_len] == ' ') {
+                       int len = eol - line - key_len;
+                       char *ret = xmalloc(len);
+                       memcpy(ret, line + key_len + 1, len - 1);
+                       ret[len - 1] = '\0';
+                       return ret;
+               }
+               line = next;
+       }
+}
+
+static char *replace_encoding_header(char *buf, char *encoding)
+{
+       char *encoding_header = strstr(buf, "\nencoding ");
+       char *end_of_encoding_header;
+       int encoding_header_pos;
+       int encoding_header_len;
+       int new_len;
+       int need_len;
+       int buflen = strlen(buf) + 1;
+
+       if (!encoding_header)
+               return buf; /* should not happen but be defensive */
+       encoding_header++;
+       end_of_encoding_header = strchr(encoding_header, '\n');
+       if (!end_of_encoding_header)
+               return buf; /* should not happen but be defensive */
+       end_of_encoding_header++;
+
+       encoding_header_len = end_of_encoding_header - encoding_header;
+       encoding_header_pos = encoding_header - buf;
+
+       if (is_encoding_utf8(encoding)) {
+               /* we have re-coded to UTF-8; drop the header */
+               memmove(encoding_header, end_of_encoding_header,
+                       buflen - (encoding_header_pos + encoding_header_len));
+               return buf;
+       }
+       new_len = strlen(encoding);
+       need_len = new_len + strlen("encoding \n");
+       if (encoding_header_len < need_len) {
+               buf = xrealloc(buf, buflen + (need_len - encoding_header_len));
+               encoding_header = buf + encoding_header_pos;
+               end_of_encoding_header = encoding_header + encoding_header_len;
+       }
+       memmove(end_of_encoding_header + (need_len - encoding_header_len),
+               end_of_encoding_header,
+               buflen - (encoding_header_pos + encoding_header_len));
+       memcpy(encoding_header + 9, encoding, strlen(encoding));
+       encoding_header[9 + new_len] = '\n';
+       return buf;
+}
+
+static char *logmsg_reencode(const struct commit *commit)
+{
+       char *encoding;
+       char *out;
+       char *output_encoding = (git_log_output_encoding
+                                ? git_log_output_encoding
+                                : git_commit_encoding);
+
+       if (!output_encoding)
+               output_encoding = "utf-8";
+       else if (!*output_encoding)
+               return NULL;
+       encoding = get_header(commit, "encoding");
+       if (!encoding || !strcmp(encoding, output_encoding)) {
+               free(encoding);
+               return NULL;
+       }
+       out = reencode_string(commit->buffer, output_encoding, encoding);
+       if (out)
+               out = replace_encoding_header(out, output_encoding);
+
+       free(encoding);
+       if (!out)
+               return NULL;
+       return out;
+}
+
+unsigned long pretty_print_commit(enum cmit_fmt fmt,
+                                 const struct commit *commit,
+                                 unsigned long len,
+                                 char *buf, unsigned long space,
+                                 int abbrev, const char *subject,
+                                 const char *after_subject,
+                                 int relative_date)
 {
        int hdr = 1, body = 0;
        unsigned long offset = 0;
-       int parents = 0;
+       int indent = 4;
+       int parents_shown = 0;
+       const char *msg = commit->buffer;
+       int plain_non_ascii = 0;
+       char *reencoded = logmsg_reencode(commit);
+
+       if (reencoded)
+               msg = reencoded;
+
+       if (fmt == CMIT_FMT_ONELINE || fmt == CMIT_FMT_EMAIL)
+               indent = 0;
+
+       /* After-subject is used to pass in Content-Type: multipart
+        * MIME header; in that case we do not have to do the
+        * plaintext content type even if the commit message has
+        * non 7-bit ASCII character.  Otherwise, check if we need
+        * to say this is not a 7-bit ASCII.
+        */
+       if (fmt == CMIT_FMT_EMAIL && !after_subject) {
+               int i, ch, in_body;
+
+               for (in_body = i = 0; (ch = msg[i]) && i < len; i++) {
+                       if (!in_body) {
+                               /* author could be non 7-bit ASCII but
+                                * the log may be so; skip over the
+                                * header part first.
+                                */
+                               if (ch == '\n' &&
+                                   i + 1 < len && msg[i+1] == '\n')
+                                       in_body = 1;
+                       }
+                       else if (ch & 0x80) {
+                               plain_non_ascii = 1;
+                               break;
+                       }
+               }
+       }
 
        for (;;) {
                const char *line = msg;
@@ -300,7 +763,8 @@ unsigned long pretty_print_commit(enum cmit_fmt fmt, const char *msg, unsigned l
                if (hdr) {
                        if (linelen == 1) {
                                hdr = 0;
-                               buf[offset++] = '\n';
+                               if ((fmt != CMIT_FMT_ONELINE) && !subject)
+                                       buf[offset++] = '\n';
                                continue;
                        }
                        if (fmt == CMIT_FMT_RAW) {
@@ -311,33 +775,91 @@ unsigned long pretty_print_commit(enum cmit_fmt fmt, const char *msg, unsigned l
                        if (!memcmp(line, "parent ", 7)) {
                                if (linelen != 48)
                                        die("bad parent line in commit");
-                               offset += add_parent_info(fmt, buf + offset, line, ++parents);
+                               continue;
                        }
-                       if (!memcmp(line, "author ", 7))
-                               offset += add_user_info("Author", fmt, buf + offset, line + 7);
-                       if (fmt == CMIT_FMT_FULL) {
-                               if (!memcmp(line, "committer ", 10))
-                                       offset += add_user_info("Commit", fmt, buf + offset, line + 10);
+
+                       if (!parents_shown) {
+                               offset += add_merge_info(fmt, buf + offset,
+                                                        commit, abbrev);
+                               parents_shown = 1;
+                               continue;
                        }
+                       /*
+                        * MEDIUM == DEFAULT shows only author with dates.
+                        * FULL shows both authors but not dates.
+                        * FULLER shows both authors and dates.
+                        */
+                       if (!memcmp(line, "author ", 7))
+                               offset += add_user_info("Author", fmt,
+                                                       buf + offset,
+                                                       line + 7,
+                                                       relative_date);
+                       if (!memcmp(line, "committer ", 10) &&
+                           (fmt == CMIT_FMT_FULL || fmt == CMIT_FMT_FULLER))
+                               offset += add_user_info("Commit", fmt,
+                                                       buf + offset,
+                                                       line + 10,
+                                                       relative_date);
                        continue;
                }
 
-               if (is_empty_line(line, linelen)) {
+               if (!subject)
+                       body = 1;
+
+               if (is_empty_line(line, &linelen)) {
                        if (!body)
                                continue;
+                       if (subject)
+                               continue;
                        if (fmt == CMIT_FMT_SHORT)
                                break;
-               } else {
-                       body = 1;
                }
-               memset(buf + offset, ' ', 4);
-               memcpy(buf + offset + 4, line, linelen);
-               offset += linelen + 4;
+
+               if (subject) {
+                       int slen = strlen(subject);
+                       memcpy(buf + offset, subject, slen);
+                       offset += slen;
+                       offset += add_rfc2047(buf + offset, line, linelen);
+               }
+               else {
+                       memset(buf + offset, ' ', indent);
+                       memcpy(buf + offset + indent, line, linelen);
+                       offset += linelen + indent;
+               }
+               buf[offset++] = '\n';
+               if (fmt == CMIT_FMT_ONELINE)
+                       break;
+               if (subject && plain_non_ascii) {
+                       static const char header[] =
+                               "Content-Type: text/plain; charset=UTF-8\n"
+                               "Content-Transfer-Encoding: 8bit\n";
+                       memcpy(buf + offset, header, sizeof(header)-1);
+                       offset += sizeof(header)-1;
+               }
+               if (after_subject) {
+                       int slen = strlen(after_subject);
+                       if (slen > space - offset - 1)
+                               slen = space - offset - 1;
+                       memcpy(buf + offset, after_subject, slen);
+                       offset += slen;
+                       after_subject = NULL;
+               }
+               subject = NULL;
        }
-       /* Make sure there is an EOLN */
-       if (buf[offset - 1] != '\n')
+       while (offset && isspace(buf[offset-1]))
+               offset--;
+       /* Make sure there is an EOLN for the non-oneline case */
+       if (fmt != CMIT_FMT_ONELINE)
+               buf[offset++] = '\n';
+       /*
+        * make sure there is another EOLN to separate the headers from whatever
+        * body the caller appends if we haven't already written a body
+        */
+       if (fmt == CMIT_FMT_EMAIL && !body)
                buf[offset++] = '\n';
        buf[offset] = '\0';
+
+       free(reencoded);
        return offset;
 }
 
@@ -355,20 +877,38 @@ struct commit *pop_commit(struct commit_list **stack)
 
 int count_parents(struct commit * commit)
 {
-        int count = 0;
+        int count;
         struct commit_list * parents = commit->parents;
-        for (count=0;parents; parents=parents->next,count++)
-          ;
+        for (count = 0; parents; parents = parents->next,count++)
+               ;
         return count;
 }
 
+void topo_sort_default_setter(struct commit *c, void *data)
+{
+       c->util = data;
+}
+
+void *topo_sort_default_getter(struct commit *c)
+{
+       return c->util;
+}
+
 /*
  * Performs an in-place topological sort on the list supplied.
  */
-void sort_in_topological_order(struct commit_list ** list)
+void sort_in_topological_order(struct commit_list ** list, int lifo)
+{
+       sort_in_topological_order_fn(list, lifo, topo_sort_default_setter,
+                                    topo_sort_default_getter);
+}
+
+void sort_in_topological_order_fn(struct commit_list ** list, int lifo,
+                                 topo_sort_set_fn_t setter,
+                                 topo_sort_get_fn_t getter)
 {
        struct commit_list * next = *list;
-       struct commit_list * work = NULL;
+       struct commit_list * work = NULL, **insert;
        struct commit_list ** pptr = list;
        struct sort_node * nodes;
        struct sort_node * next_nodes;
@@ -379,6 +919,9 @@ void sort_in_topological_order(struct commit_list ** list)
                next = next->next;
                count++;
        }
+       
+       if (!count)
+               return;
        /* allocate an array to help sort the list */
        nodes = xcalloc(count, sizeof(*nodes));
        /* link the list to the array */
@@ -386,7 +929,7 @@ void sort_in_topological_order(struct commit_list ** list)
        next=*list;
        while (next) {
                next_nodes->list_item = next;
-               next->item->object.util = next_nodes;
+               setter(next->item, next_nodes);
                next_nodes++;
                next = next->next;
        }
@@ -396,8 +939,8 @@ void sort_in_topological_order(struct commit_list ** list)
                struct commit_list * parents = next->item->parents;
                while (parents) {
                        struct commit * parent=parents->item;
-                       struct sort_node * pn = (struct sort_node *)parent->object.util;
-                       
+                       struct sort_node * pn = (struct sort_node *) getter(parent);
+
                        if (pn)
                                pn->indegree++;
                        parents=parents->next;
@@ -412,33 +955,41 @@ void sort_in_topological_order(struct commit_list ** list)
          * the tips serve as a starting set for the work queue.
          */
        next=*list;
+       insert = &work;
        while (next) {
-               struct sort_node * node = (struct sort_node *)next->item->object.util;
+               struct sort_node * node = (struct sort_node *) getter(next->item);
 
                if (node->indegree == 0) {
-                       commit_list_insert(next->item, &work);
+                       insert = &commit_list_insert(next->item, insert)->next;
                }
                next=next->next;
        }
+
        /* process the list in topological order */
+       if (!lifo)
+               sort_by_date(&work);
        while (work) {
                struct commit * work_item = pop_commit(&work);
-               struct sort_node * work_node = (struct sort_node *)work_item->object.util;
+               struct sort_node * work_node = (struct sort_node *) getter(work_item);
                struct commit_list * parents = work_item->parents;
 
                while (parents) {
                        struct commit * parent=parents->item;
-                       struct sort_node * pn = (struct sort_node *)parent->object.util;
-                       
+                       struct sort_node * pn = (struct sort_node *) getter(parent);
+
                        if (pn) {
-                               /* 
+                               /*
                                 * parents are only enqueued for emission 
                                  * when all their children have been emitted thereby
                                  * guaranteeing topological order.
                                  */
                                pn->indegree--;
-                               if (!pn->indegree) 
-                                       commit_list_insert(parent, &work);
+                               if (!pn->indegree) {
+                                       if (!lifo)
+                                               insert_by_date(parent, &work);
+                                       else
+                                               commit_list_insert(parent, &work);
+                               }
                        }
                        parents=parents->next;
                }
@@ -449,7 +1000,168 @@ void sort_in_topological_order(struct commit_list ** list)
                *pptr = work_node->list_item;
                pptr = &(*pptr)->next;
                *pptr = NULL;
-               work_item->object.util = NULL;
+               setter(work_item, NULL);
        }
        free(nodes);
 }
+
+/* merge-rebase stuff */
+
+/* bits #0..15 in revision.h */
+#define PARENT1                (1u<<16)
+#define PARENT2                (1u<<17)
+#define STALE          (1u<<18)
+#define RESULT         (1u<<19)
+
+static struct commit *interesting(struct commit_list *list)
+{
+       while (list) {
+               struct commit *commit = list->item;
+               list = list->next;
+               if (commit->object.flags & STALE)
+                       continue;
+               return commit;
+       }
+       return NULL;
+}
+
+static struct commit_list *merge_bases(struct commit *one, struct commit *two)
+{
+       struct commit_list *list = NULL;
+       struct commit_list *result = NULL;
+
+       if (one == two)
+               /* We do not mark this even with RESULT so we do not
+                * have to clean it up.
+                */
+               return commit_list_insert(one, &result);
+
+       parse_commit(one);
+       parse_commit(two);
+
+       one->object.flags |= PARENT1;
+       two->object.flags |= PARENT2;
+       insert_by_date(one, &list);
+       insert_by_date(two, &list);
+
+       while (interesting(list)) {
+               struct commit *commit;
+               struct commit_list *parents;
+               struct commit_list *n;
+               int flags;
+
+               commit = list->item;
+               n = list->next;
+               free(list);
+               list = n;
+
+               flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
+               if (flags == (PARENT1 | PARENT2)) {
+                       if (!(commit->object.flags & RESULT)) {
+                               commit->object.flags |= RESULT;
+                               insert_by_date(commit, &result);
+                       }
+                       /* Mark parents of a found merge stale */
+                       flags |= STALE;
+               }
+               parents = commit->parents;
+               while (parents) {
+                       struct commit *p = parents->item;
+                       parents = parents->next;
+                       if ((p->object.flags & flags) == flags)
+                               continue;
+                       parse_commit(p);
+                       p->object.flags |= flags;
+                       insert_by_date(p, &list);
+               }
+       }
+
+       /* Clean up the result to remove stale ones */
+       list = result; result = NULL;
+       while (list) {
+               struct commit_list *n = list->next;
+               if (!(list->item->object.flags & STALE))
+                       insert_by_date(list->item, &result);
+               free(list);
+               list = n;
+       }
+       return result;
+}
+
+struct commit_list *get_merge_bases(struct commit *one,
+                                   struct commit *two,
+                                    int cleanup)
+{
+       const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
+       struct commit_list *list;
+       struct commit **rslt;
+       struct commit_list *result;
+       int cnt, i, j;
+
+       result = merge_bases(one, two);
+       if (one == two)
+               return result;
+       if (!result || !result->next) {
+               if (cleanup) {
+                       clear_commit_marks(one, all_flags);
+                       clear_commit_marks(two, all_flags);
+               }
+               return result;
+       }
+
+       /* There are more than one */
+       cnt = 0;
+       list = result;
+       while (list) {
+               list = list->next;
+               cnt++;
+       }
+       rslt = xcalloc(cnt, sizeof(*rslt));
+       for (list = result, i = 0; list; list = list->next)
+               rslt[i++] = list->item;
+       free_commit_list(result);
+
+       clear_commit_marks(one, all_flags);
+       clear_commit_marks(two, all_flags);
+       for (i = 0; i < cnt - 1; i++) {
+               for (j = i+1; j < cnt; j++) {
+                       if (!rslt[i] || !rslt[j])
+                               continue;
+                       result = merge_bases(rslt[i], rslt[j]);
+                       clear_commit_marks(rslt[i], all_flags);
+                       clear_commit_marks(rslt[j], all_flags);
+                       for (list = result; list; list = list->next) {
+                               if (rslt[i] == list->item)
+                                       rslt[i] = NULL;
+                               if (rslt[j] == list->item)
+                                       rslt[j] = NULL;
+                       }
+               }
+       }
+
+       /* Surviving ones in rslt[] are the independent results */
+       result = NULL;
+       for (i = 0; i < cnt; i++) {
+               if (rslt[i])
+                       insert_by_date(rslt[i], &result);
+       }
+       free(rslt);
+       return result;
+}
+
+int in_merge_bases(struct commit *rev1, struct commit *rev2)
+{
+       struct commit_list *bases, *b;
+       int ret = 0;
+
+       bases = get_merge_bases(rev1, rev2, 1);
+       for (b = bases; b; b = b->next) {
+               if (!hashcmp(rev1->object.sha1, b->item->object.sha1)) {
+                       ret = 1;
+                       break;
+               }
+       }
+
+       free_commit_list(bases);
+       return ret;
+}