Fossil

** Reset the undo memory.
*/
void undo_reset(void){
  static const char zSql[] =
    @ DROP TABLE IF EXISTS undo;
    @ DROP TABLE IF EXISTS undo_vfile;
    @ DROP TABLE IF EXISTS undo_vmerge;
    @ DROP TABLE IF EXISTS undo_pending;
    ;
  db_multi_exec(zSql);
  db_lset_int("undo_available", 0);
  db_lset_int("undo_checkout", 0);
}

/*
** The following variable stores the original command-line of the
** command that is a candidate to be undone.
*/
static char *undoCmd = 0;

/*
** Capture the current command-line and store it as part of the undo
** state.  This routine is called before options are extracted from the
** command-line so that we can record the complete command-line.
*/
void undo_capture_command_line(void){
  Blob cmdline;
  int i;
  assert( undoCmd==0 );
  blob_zero(&cmdline);
  for(i=1; i<g.argc; i++){
    if( i>1 ) blob_append(&cmdline, " ", 1);
    blob_append(&cmdline, g.argv[i], -1);
  }
  undoCmd = blob_str(&cmdline);
}

/*
** This flag is true if we are in the process of collecting file changes
** for undo.  When this flag is false, undo_save() is a no-op.
*/
static int undoActive = 0;

    @   pathname TEXT UNIQUE,             -- Name of the file
    @   redoflag BOOLEAN,                 -- 0 for undoable.  1 for redoable
    @   existsflag BOOLEAN,               -- True if the file exists
    @   content BLOB                      -- Saved content
    @ );
    @ CREATE TABLE %s.undo_vfile AS SELECT * FROM vfile;
    @ CREATE TABLE %s.undo_vmerge AS SELECT * FROM vmerge;
    @ CREATE TABLE %s.undo_pending(undoId INTEGER PRIMARY KEY);
  ;
  undo_reset();
  if( strcmp(g.zMainDbType,zDb)==0 ) zDb = "main";
  db_multi_exec(zSql, zDb, zDb, zDb, zDb);
  cid = db_lget_int("checkout", 0);
  db_lset_int("undo_checkout", cid);
  db_lset_int("undo_available", 1);
  db_lset("undo_cmdline", undoCmd);
  undoActive = 1;
}

/*
** This flag is true if one or more files have changed and have been
** recorded in the undo log but the undo log has not yet been committed.
**

  undoActive = 0;
  printf("Rolling back prior filesystem changes...\n");
  undo_all_filesystem(0);
}

/*
** COMMAND: undo
** COMMAND: redo
**
** Usage: %fossil undo ?FILENAME...?
** Usage: %fossil undo ?--explain? ?FILENAME...?
**    or: %fossil redo ?--explain? ?FILENAME...?
**
** Undo the most recent update or merge or revert operation.  If FILENAME is
** specified then restore the content of the named file(s) but otherwise
** leave the update or merge or revert in effect.
** leave the update or merge or revert in effect.  The redo command undoes
** the effect of the most recent undo.
**
** If the --explain option is present, not changes are made and instead
** the undo or redo command explains what actions the undo or redo would
** have done had the --explain been omitted.
**
** A single level of undo/redo is supported.  The undo/redo stack
** is cleared by the commit and checkout commands.
*/
void undo_cmd(void){
  int isRedo = g.argv[1][0]=='r';
  int undo_available;
  int explainFlag = find_option("explain", 0, 0)!=0;
  const char *zCmd = isRedo ? "redo" : "undo";
  db_must_be_within_tree();
  db_begin_transaction();
  undo_available = db_lget_int("undo_available", 0);
  if( g.argc==2 ){
    if( undo_available!=1 ){
  if( explainFlag ){
    if( undo_available==0 ){
      fossil_fatal("no update or merge operation is available to undo");
    }
    undo_all(0);
    db_lset_int("undo_available", 2);
  }else if( g.argc>=3 ){
    int i;
    if( undo_available==0 ){
      fossil_fatal("no update or merge operation is available to undo");
      printf("No undo or redo is available\n");
    }else{
      Stmt q;
      int nChng = 0;
      zCmd = undo_available==1 ? "undo" : "redo";
      printf("A %s is available for the following command:\n\n   %s %s\n\n",
    }
    for(i=2; i<g.argc; i++){
      const char *zFile = g.argv[i];
      Blob path;
      file_tree_name(zFile, &path, 1);
      undo_one(blob_str(&path), 0);
      blob_reset(&path);
              zCmd, g.argv[0], db_lget("undo_cmdline", "???"));
      db_prepare(&q,
        "SELECT existsflag, pathname FROM undo ORDER BY pathname"
      );
      while( db_step(&q)==SQLITE_ROW ){
        if( nChng==0 ){
    }
  }
  db_end_transaction(0);
}

          printf("The following file changes would occur if the "
/*
** COMMAND: redo
**
** Usage: %fossil redo ?FILENAME...?
**
** Redo an update or merge or revert operation that has been undone
** by the undo command.  If FILENAME is specified then restore the changes
** associated with the named file(s) but otherwise leave the update
** or merge undone.
**
** A single level of undo/redo is supported.  The undo/redo stack
** is cleared by the commit and checkout commands.
                 "command above is %sne:\n\n", zCmd);
*/
void redo_cmd(void){
  int undo_available;
  db_must_be_within_tree();
  db_begin_transaction();
        }
        nChng++;
        printf("%s %s\n", 
           db_column_int(&q,0) ? "UPDATE" : "DELETE",
           db_column_text(&q, 1)
        );
      }
      db_finalize(&q);
  undo_available = db_lget_int("undo_available", 0);
  if( g.argc==2 ){
    if( undo_available!=2 ){
      fossil_fatal("no undone update or merge operation is available to redo");
      if( nChng==0 ){
        printf("No file changes would occur with this undo/redo.\n");
      }
    }
  }else if( g.argc==2 ){
    if( undo_available!=(1+isRedo) ){
      fossil_fatal("nothing to %s", zCmd);
    }
    undo_all(1);
    db_lset_int("undo_available", 1);
    undo_all(isRedo);
    db_lset_int("undo_available", 2-isRedo);
  }else if( g.argc>=3 ){
    int i;
    if( undo_available==0 ){
      fossil_fatal("no update or merge operation is available to redo");
      fossil_fatal("nothing to %s", zCmd);
    }
    for(i=2; i<g.argc; i++){
      const char *zFile = g.argv[i];
      Blob path;
      file_tree_name(zFile, &path, 1);
      undo_one(blob_str(&path), 0);
      undo_one(blob_str(&path), isRedo);
      blob_reset(&path);
    }
  }
  db_end_transaction(0);
}