Fossil

** using the "fossil purge undo" command.
**
**   fossil purge cat UUID...
**
**      Write the content of one or more artifacts in the graveyard onto
**      standard output.
**
**   fossil purge ?checkins? TAGS... ?OPTIONS?
**
**      Move the checkins identified by TAGS and all of their descendants
**      out of the repository and into the graveyard.  The "checkins" 
**      subcommand keyword is option and can be omitted as long as TAGS
**      does not conflict with any other subcommand.
**
**      If a TAGS includes a branch name then it means all the checkins
**      on the most recent occurrance of that branch.
**
**           --explain         Make no changes, but show what would happen.

**           --dry-run         Make no chances.
**
**   fossil purge list|ls ?-l?
**
**      Show the graveyard of prior purges.  The -l option gives more
**      detail in the output.
**
**   fossil purge obliterate ID...
**
**      Remove one or more purge events from the graveyard.  Once a purge
**      event is obliterated, it can no longer be undone.
**
**   fossil purge undo ID
**
**      Restore the content previously removed by purge ID.
**
** SUMMARY:
**   fossil purge cat UUID...
**   fossil purge [checkins] TAGS... [--explain]
**   fossil purge list
**   fossil purge obliterate ID...
**   fossil purge undo ID
*/
void purge_cmd(void){
  const char *zSubcmd;
  int n;
  Stmt q;
  if( g.argc<3 ) usage("SUBCOMMAND ?ARGS?");
  zSubcmd = g.argv[2];
  db_find_and_open_repository(0,0);
  n = (int)strlen(zSubcmd);
  if( strncmp(zSubcmd, "cat", n)==0 ){
    const char *zOutFile;
    int i, piid;
    Blob content;
    if( g.argc<4 ) usage("cat UUID...");
    for(i=3; i<g.argc; i++){
      piid = db_int(0, "SELECT piid FROM purgeitem WHERE uuid LIKE '%q%%'",
                       g.argv[i]);
      if( piid==0 ) fossil_fatal("no such item: %s", g.argv[3]);
      purge_extract_item(piid, &content);
      blob_write_to_file(&content, "-");
      blob_reset(&content);
    }
  /* The "checkins" subcommand goes here in alphabetical order, but it must
  ** be moved to the end since it is the default case */
  }else if( strncmp(zSubcmd, "list", n)==0 || strcmp(zSubcmd,"ls")==0 ){
    int showDetail = find_option("l","l",0)!=0;
    if( db_int(-1,"PRAGMA table_info('purgeevent')")<0 ) return;
    db_prepare(&q, "SELECT peid, datetime(ctime,'unixepoch','localtime')"
                   " FROM purgeevent");
    while( db_step(&q)==SQLITE_ROW ){
      fossil_print("%4d on %s\n", db_column_int(&q,0), db_column_text(&q,1));
      if( showDetail ){
        purge_list_event_content(db_column_int(&q,0));
      }
    }
    db_finalize(&q);
  }else if( strncmp(zSubcmd, "obliterate", n)==0 ){
    int i;
    if( g.argc<4 ) usage("obliterate ID...");
    db_begin_transaction();
    for(i=3; i<g.argc; i++){
      int peid = atoi(g.argv[i]);
      if( !db_exists("SELECT 1 FROM purgeevent WHERE peid=%d",peid) ){
        fossil_fatal("no such purge event: %s", g.argv[i]);
      }
      db_multi_exec(
        "DELETE FROM purgeevent WHERE peid=%d;"
        "DELETE FROM purgeitem WHERE peid=%d;",
        peid, peid
      );
    }
    db_end_transaction(0);
  }else if( strncmp(zSubcmd, "undo", n)==0 ){
    int peid;
    if( g.argc!=4 ) usage("undo ID");
    peid = atoi(g.argv[3]);
    db_begin_transaction();
    db_multi_exec(
      "CREATE TEMP TABLE ix("

    );
    manifest_crosslink_begin();
    purge_item_resurrect(0, 0);
    manifest_crosslink_end(0);
    db_multi_exec("DELETE FROM purgeevent WHERE peid=%d", peid);
    db_multi_exec("DELETE FROM purgeitem WHERE peid=%d", peid);
    db_end_transaction(0);












  }else{
    /* The "checkins" command is the default and so must occur last */
    int explainOnly = find_option("explain",0,0)!=0;
    int dryRun = find_option("dry-run",0,0)!=0;
    const char *zTag;
    int i;
    int vid;
    int nCkin;
    int nArtifact;
    verify_all_options();
    db_begin_transaction();
    i = strncmp(zSubcmd,"checkins",n)==0 ? 3 : 2;
    if( i>=g.argc ) usage("[checkin] TAGS... [--explain]");
    db_multi_exec("CREATE TEMP TABLE ok(rid INTEGER PRIMARY KEY)");
    for(; i<g.argc; i++){
      int r = name_to_typed_rid(g.argv[i], "br");
      compute_descendants(r, 1000000000);
    }
    vid = db_lget_int("checkout",0);