/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */
/* 
 *
 *   Copyright (C) 2007 UChicago/Argonne LLC
 *   See COPYRIGHT notice in top-level directory.
 */

#include "adio.h"

/* 
 * Scalable open:  for file systems capable of having one process
 * create/open a file and broadcast the result to everyone else. 
 * - Does not need one process to create the file
 * - Does not need special handling for CREATE|EXCL
 */
void ADIOI_SCALEABLE_OpenColl(ADIO_File fd, int rank, 
		int access_mode, int *error_code)
{    
    int orig_amode_wronly;

    /* if we are doing deferred open, non-aggregators should return now */
    if (fd->hints->deferred_open && !(fd->is_agg)) {
	*error_code = MPI_SUCCESS;
	return;
    } 
    
    /* For writing with data sieving, a read-modify-write is needed. If 
       the file is opened for write_only, the read will fail. Therefore,
       if write_only, open the file as read_write, but record it as
       write_only in fd, so that get_amode returns the right answer. */

    orig_amode_wronly = access_mode;
    if (access_mode & ADIO_WRONLY) {
	access_mode = access_mode ^ ADIO_WRONLY;
	access_mode = access_mode | ADIO_RDWR;
    }
    fd->access_mode = access_mode;

    (*(fd->fns->ADIOI_xxx_Open))(fd, error_code);

    /* if error, may be it was due to the change in amode above. 
       therefore, reopen with access mode provided by the user.*/ 
    fd->access_mode = orig_amode_wronly;  
    if (*error_code != MPI_SUCCESS) 
        (*(fd->fns->ADIOI_xxx_Open))(fd, error_code);

    /* for deferred open: this process has opened the file (because if we are
     * not an aggregaor and we are doing deferred open, we returned earlier)*/
    fd->is_open = 1;

}

/* 
 * vim: ts=8 sts=4 sw=4 noexpandtab 
 */