}
  zValue = g.argc==5 ? g.argv[4] : 0;
  db_begin_transaction();
  tag_insert(zTag, tagtype, zValue, -1, 0.0, rid);
  db_end_transaction(0); 
}

/*
** Prepare an artifact that describes a fork from a certain baseline.
** Furthermore a propagating symbolic tag will be inserted and
** all other propagating symbolic tags will be cancelled.
**
** The changes are appended at the Blob pCtrl. However the manifest
** is not complete at that stage.
*/
static void tag_prepare_fork(
  Blob *pCtrl, 
  const char *zTagname,
  int rid,
  int preflen                 /* Tag prefix length to adjust name if reqd */
){
  Stmt q;
  Manifest origin;
  Blob originContent;
  char *zDate;
  int i;

  blob_appendf(pCtrl, "C Create\\snamed\\sfork\\s%s\n", zTagname+preflen);
  content_get(rid, &originContent);
  manifest_parse(&origin, &originContent);
  zDate = db_text(0, "SELECT datetime('now')");
  zDate[10] = 'T';
  blob_appendf(pCtrl, "D %s\n", zDate);
  for(i=0; i<origin.nFile; ++i){
    blob_appendf(pCtrl, "F %s %s %s\n",
                 origin.aFile[i].zName,
                 origin.aFile[i].zUuid,
                 origin.aFile[i].zPerm);
  }
  if( origin.nParent>0 ){
    blob_appendf(pCtrl, "P %s\n", origin.azParent[0]);
  }
  blob_appendf(pCtrl, "R %s\n", origin.zRepoCksum);
  blob_appendf(pCtrl, "T *%F *", zTagname);

  /* Cancel any sym- tags that propagate */
  db_prepare(&q,
      "SELECT tagname FROM tagxref, tag"
      " WHERE tagxref.rid=%d AND tagxref.tagid=tag.tagid"
      "   AND tagtype>0 AND tagname LIKE 'sym-%%'"
      " ORDER BY tagname",
      rid);
  while( db_step(&q)==SQLITE_ROW ){
    const char *zTag = db_column_text(&q, 0);
    blob_appendf(pCtrl, "\nT -%s *", zTag);
  }
  db_finalize(&q);

  /* Cleanup */
  manifest_clear(&origin);
}

/*
** Add a control record to the repository that either creates
** or cancels a tag.
*/
static void tag_add_artifact(

  const char *zTagname,       /* The tag to add or cancel */
  const char *zObjName,       /* Name of object attached to */
  const char *zValue,         /* Value for the tag.  Might be NULL */
  int tagtype,                /* 0:cancel 1:singleton 2:propagated */
  int fork,                   /* Should a fork created from zObjName? */
  int preflen                 /* Tag prefix length to adjust name if reqd */
){
  int rid;
  int nrid;
  char *zDate;
  Blob uuid;
  Blob ctrl;
  Blob cksum;
  static const char zTagtype[] = { '-', '+', '*' };

  assert( tagtype>=0 && tagtype<=2 );
  user_select();
  blob_zero(&uuid);
  blob_append(&uuid, zObjName, -1);
  if( name_to_uuid(&uuid, 9) ){
    return;
  }
  rid = name_to_rid(blob_str(&uuid));
  blob_zero(&ctrl);


  if( validate16(zTagname, strlen(zTagname)) ){
    fossil_fatal(
       "invalid tag name \"%s\" - might be confused with"
       " a hexadecimal artifact ID",
       zTagname
    );
  }
  if( fork ){
    tag_prepare_fork(&ctrl, zTagname, rid, preflen);
  }else{
    zDate = db_text(0, "SELECT datetime('now')");
    zDate[10] = 'T';
    blob_appendf(&ctrl, "D %s\n", zDate);
    blob_appendf(&ctrl, "T %c%F %b", zTagtype[tagtype], zTagname, &uuid);
  }

  if( tagtype && zValue && zValue[0] ){
    blob_appendf(&ctrl, " %F\n", zValue);
  }else{
    blob_appendf(&ctrl, "\n");
  }
  blob_appendf(&ctrl, "U %F\n", g.zLogin);
  md5sum_blob(&ctrl, &cksum);
  blob_appendf(&ctrl, "Z %b\n", &cksum);

/*
** COMMAND: tag
** Usage: %fossil tag SUBCOMMAND ...
**
** Run various subcommands to control tags and properties
**
**     %fossil tag add ?--raw? TAGNAME BASELINE ?VALUE?
**
**         Add a new tag or property to BASELINE. The tag will
**         be usable instead of a BASELINE in commands such as
**         update and merge.
**
**     %fossil tag branch ?--raw? ?--nofork? TAGNAME BASELINE ?VALUE?
**
**         A fork will be created so that the new checkin
**         is a sibling of BASELINE and identical to it except
**         for a generated comment. Then the new tag will
**         be added to the new checkin and propagated to
**         all direct children.  Additionally all symbolic
**         tags of that checkin inherited from BASELINE will
**         be cancelled.
**
**         However, if the option --nofork is given, no
**         fork will be created and the tag/property will be
**         added to BASELINE directly. No tags will be canceled.
**
**     %fossil tag cancel ?--raw? TAGNAME BASELINE
**
**         Remove the tag TAGNAME from BASELINE, and also remove
**         the propagation of the tag to any descendants.
**
**     %fossil tag find ?--raw? TAGNAME
**
**         List all baselines that use TAGNAME
**
**     %fossil tag list ?--raw? ?BASELINE?
**
**         List all tags, or if BASELINE is supplied, list
**         all tags and their values for BASELINE.
**
** The option --raw allows the manipulation of all types of tags
** used for various internal purposes in fossil. It also shows
** "cancel" tags for the "find" and "list" subcommands. You should
** not use this option to make changes unless you are sure what
** you are doing.
**

**   fossil update tag:decaf
**
** will assume that "decaf" is a tag/branch name.
**
*/
void tag_cmd(void){
  int n;
  int raw = find_option("raw","",0)!=0;
  int fork = find_option("nofork","",0)==0;
  const char *prefix = raw ? "" : "sym-";
  int preflen = strlen(prefix);
  Blob tagname;

  db_find_and_open_repository(1);
  if( g.argc<3 ){
    goto tag_cmd_usage;
  }
  n = strlen(g.argv[2]);
  if( n==0 ){
    goto tag_cmd_usage;
  }

  blob_set(&tagname, prefix);

  if( strncmp(g.argv[2],"add",n)==0 ){
    char *zValue;
    if( g.argc!=5 && g.argc!=6 ){
      usage("add ?--raw? TAGNAME BASELINE ?VALUE?");
    }
    blob_append(&tagname, g.argv[3], strlen(g.argv[3]));
    zValue = g.argc==6 ? g.argv[5] : 0;
    tag_add_artifact(blob_str(&tagname), g.argv[4], zValue, 1, 0, 0);
  }else

  if( strncmp(g.argv[2],"branch",n)==0 ){
    char *zValue;
    if( g.argc!=5 && g.argc!=6 ){
      usage("branch ?--raw? ?--nofork? TAGNAME BASELINE ?VALUE?");
    }
    blob_append(&tagname, g.argv[3], strlen(g.argv[3]));
    zValue = g.argc==6 ? g.argv[5] : 0;
    tag_add_artifact(blob_str(&tagname), g.argv[4], zValue, 2, fork!=0,
                                                      preflen);
    if( fork ){
      const char *zUuid = db_text(0, "SELECT uuid, MAX(rowid) FROM blob");
      printf("New_Fork \"%s\": %s\n", g.argv[3], zUuid);
    }
  }else

  if( strncmp(g.argv[2],"cancel",n)==0 ){
    if( g.argc!=5 ){
      usage("cancel ?--raw? TAGNAME BASELINE");
    }
    blob_append(&tagname, g.argv[3], strlen(g.argv[3]));
    tag_add_artifact(blob_str(&tagname), g.argv[4], 0, 0, 0, 0);
  }else

  if( strncmp(g.argv[2],"find",n)==0 ){
    Stmt q;
    if( g.argc!=4 ){
      usage("find ?--raw? TAGNAME");
    }
    blob_append(&tagname, g.argv[3], strlen(g.argv[3]));
    db_prepare(&q,
      "SELECT blob.uuid FROM tagxref, blob"
      " WHERE tagid=(SELECT tagid FROM tag WHERE tagname=%B)"
      "   AND tagxref.tagtype > %d"
      "   AND blob.rid=tagxref.rid", &tagname, raw ? -1 : 0

    );
    while( db_step(&q)==SQLITE_ROW ){
      printf("%s\n", db_column_text(&q, 0));
    }
    db_finalize(&q);

















  }else

  if( strncmp(g.argv[2],"list",n)==0 ){
    Stmt q;
    if( g.argc==3 ){
      db_prepare(&q, 
        "SELECT tagname FROM tag"
        " WHERE EXISTS(SELECT 1 FROM tagxref"
        "               WHERE tagid=tag.tagid"
        "                 AND tagtype>%d)"
        " ORDER BY tagname",
        raw ? -1 : 0
      );
      while( db_step(&q)==SQLITE_ROW ){
        const char *name = db_column_text(&q, 0);
        if( raw || strncmp(name, prefix, preflen)==0 ){
          printf("%s\n", name+preflen);


        }
      }
      db_finalize(&q);
    }else if( g.argc==4 ){
      int rid = name_to_rid(g.argv[3]);
      db_prepare(&q,
        "SELECT tagname, value FROM tagxref, tag"
        " WHERE tagxref.rid=%d AND tagxref.tagid=tag.tagid"
        "   AND tagtype>%d"
        " ORDER BY tagname",
        rid,
        raw ? -1 : 0
      );
      while( db_step(&q)==SQLITE_ROW ){
        const char *zName = db_column_text(&q, 0);
        const char *zValue = db_column_text(&q, 1);
        if( zValue ){
          if( raw || strncmp(zName, prefix, preflen)==0 ){
            printf("%s=%s\n", zName+preflen, zValue);
          }


        }else{
          if( raw || strncmp(zName, prefix, preflen)==0 ){
            printf("%s\n", zName+preflen);
          }
        }
      }
      db_finalize(&q);
    }else{
      usage("tag list ?BASELINE?");
    }
  }else
  {
    goto tag_cmd_usage;
  }

  /* Cleanup */
  blob_reset(&tagname);
  return;

tag_cmd_usage:
  usage("add|branch|cancel|find|list ...");
}