Fossil

@ -- Assignments of tags to baselines.  Note that we allow tags to
@ -- have values assigned to them.  So we are not really dealing with
@ -- tags here.  These are really properties.  But we are going to
@ -- keep calling them tags because in many cases the value is ignored.
@ --
@ CREATE TABLE tagxref(
@   tagid INTEGER REFERENCES tag,   -- The tag that added or removed
@   tagtype INTEGER,                -- 0:-,cancel  1:+,single  2:*,propagate
@   srcid INTEGER REFERENCES blob,  -- Artifact of tag. 0 for propagated tags
@   origid INTEGER REFERENCES blob, -- check-in holding propagated tag
@   value TEXT,                     -- Value of the tag.  Might be NULL.
@   mtime TIMESTAMP,                -- Time of addition or removal
@   rid INTEGER REFERENCE blob,     -- Artifact tag is applied to
@   UNIQUE(rid, tagid)
@ );

/*
** Propagate the tag given by tagid to the children of pid.
**
** This routine assumes that tagid is a tag that should be
** propagated and that the tag is already present in pid.
**
** If tagtype is 2 then the tag is being propagated from an
** ancestor node.  If tagtype is 0 it means a propagating tag is
** being blocked.
*/
static void tag_propagate(
  int pid,             /* Propagate the tag to children of this node */
  int tagid,           /* Tag to propagate */
  int tagType,         /* 2 for a propagating tag.  0 for an antitag */
  int origId,          /* Artifact of tag, when tagType==2 */
  const char *zValue,  /* Value of the tag.  Might be NULL */
  double mtime         /* Timestamp on the tag */
){
  PQueue queue;        /* Queue of check-ins to be tagged */
  Stmt s;              /* Query the children of :pid to which to propagate */
  Stmt ins;            /* INSERT INTO tagxref */
  Stmt eventupdate;    /* UPDATE event */

  assert( tagType==0 || tagType==2 );
  pqueue_init(&queue);
  pqueue_insert(&queue, pid, 0.0);

  /* Query for children of :pid to which to propagate the tag.
  ** Three returns:  (1) rid of the child.  (2) timestamp of child.
  ** (3) True to propagate or false to block.
  */
  db_prepare(&s, 
     "SELECT cid, plink.mtime,"
     "       coalesce(srcid=0 AND tagxref.mtime<:mtime, %d) AS doit"
     "  FROM plink LEFT JOIN tagxref ON cid=rid AND tagid=%d"
     " WHERE pid=:pid AND isprim",
     tagType==2, tagid
  );
  db_bind_double(&s, ":mtime", mtime);

  if( tagType==2 ){
    /* Set the propagated tag marker on checkin :rid */
    db_prepare(&ins,
       "REPLACE INTO tagxref(tagid, tagtype, srcid, origid, value, mtime, rid)"
       "VALUES(%d,2,0,%d,%Q,:mtime,:rid)",
       tagid, origId, zValue
    );
    db_bind_double(&ins, ":mtime", mtime);
  }else{
    /* Remove all references to the tag from checkin :rid */
    zValue = 0;
    db_prepare(&ins,
       "DELETE FROM tagxref WHERE tagid=%d AND rid=:rid", tagid
    );
  }
  if( tagid==TAG_BGCOLOR ){
    db_prepare(&eventupdate,

The T card represents a [./branching.wiki#tags | tag or property]
that is applied to
some other artifact.  The T card has two or three values.  The
second argument is the 40 character lowercase artifact ID of the artifact
to which the tag is to be applied. The
first value is the tag name.  The first character of the tag
is either "+", "-", or "*".  The "+" means the tag should be added
to the artifact.  The "-" means the tag should be removed.
The "*" character means the tag should be added to the artifact
and all direct descendants (but not descendents through a merge) down
to but not including the first descendant that contains a 
more recent "-" or "+" tag with the same name.
The optional third argument is the value of the tag.  A tag
without a value is a boolean.

When two or more tags with the same name are applied to the
same artifact, the tag with the latest (most recent) date is
used.