openmpi/src/file/file.h

/*
 * Copyright (c) 2004-2005 The Trustees of Indiana University.
 *                         All rights reserved.
 * Copyright (c) 2004-2005 The Trustees of the University of Tennessee.
 *                         All rights reserved.
 * $COPYRIGHT$
 * 
 * Additional copyrights may follow
 * 
 * $HEADER$
 */

#ifndef OMPI_FILE_H
#define OMPI_FILE_H

#include "mpi.h"
#include "errhandler/errhandler.h"
#include "threads/mutex.h"
#include "mca/io/io.h"

/*
 * Flags
 */
#define OMPI_FILE_ISCLOSED     0x00000001
#define OMPI_FILE_HIDDEN       0x00000002

#if defined(c_plusplus) || defined(__cplusplus)
extern "C" {
#endif

/**
 * Back-end structure for MPI_File
 */
struct ompi_file_t {
    /** Base of OBJ_* interface */
    ompi_object_t super;

    /** Communicator that this file was created with */
    struct ompi_communicator_t *f_comm;

    /** Filename that this file was created with */
    char *f_filename;

    /** Amode that this file was created with */
    int f_amode;

    /** MPI_Info that this file was created with */
    struct ompi_info_t *f_info;

    /** Bit flags */
    int32_t f_flags;

    /** Index in Fortran <-> C translation array */
    int f_f_to_c_index;

    /** Error handler.  This field does not have the "f_" prefix so
        that the OMPI_ERRHDL_* macros can find it, regardless of
        whether it's a comm, window, or file. */
    struct ompi_errhandler_t *error_handler;

    /** Type of the error handler.  This field does not have the "f_"
        prefix for the same reason as the field error_handler. */
    ompi_errhandler_type_t errhandler_type;
    
    /** Indicate what version of the IO component we're using (this
        indicates what member to look at in the union, below) */
    mca_io_base_version_t f_io_version;

    /** The selected module (note that this is a union) */
    mca_io_base_modules_t f_io_selected_module;

    /** Allow the selected module to cache data on the file */
    struct mca_io_base_file_t *f_io_selected_data;

    /* JMS: also put io request freelist here */
};
/**
 * Convenience typedef
 */
typedef struct ompi_file_t ompi_file_t;


/**
 * Back-end instances for MPI_FILE_NULL
 */
OMPI_DECLSPEC extern ompi_file_t  ompi_mpi_file_null;


/**
 * Fortran to C conversion table
 */
OMPI_DECLSPEC extern ompi_pointer_array_t ompi_file_f_to_c_table;



    /**
     * Initialize MPI_File handling.
     *
     * @retval OMPI_SUCCESS Always.
     *
     * Invoked during ompi_mpi_init().
     */
    int ompi_file_init(void);

    /**
     * Back-end to MPI_FILE_OPEN: create a file handle, select an io
     * component to use, and have that componet open the file.
     *
     * @param comm Communicator
     * @param filename String filename
     * @param amode Mode flags
     * @param info Info
     * @param fh Output file handle
     *
     * @retval OMPI_SUCCESS Upon success
     * @retval OMPI_ERR* Upon error
     *
     * Create a file handle and select an io module to be paired with
     * it.  There is a corresponding ompi_file_close() function; it
     * mainly calls OBJ_RELEASE() but also does some other error
     * handling as well.
     */
    int ompi_file_open(struct ompi_communicator_t *comm, char *filename, 
                       int amode, struct ompi_info_t *info, 
                       ompi_file_t **fh);
    
    /** 
     * Atomicly set a name on a file handle.
     *
     * @param file MPI_File handle to set the name on
     * @param name NULL-terminated string to use
     *
     * @returns OMPI_SUCCESS Always.
     *
     * At most (MPI_MAX_OBJECT_NAME-1) characters will be copied over to
     * the file name's name.  This function is performed atomically -- a
     * lock is used to ensure that there are not multiple writers to the
     * name to ensure that we don't end up with an erroneous name (e.g.,
     * a name without a \0 at the end).  After invoking this function,
     * ompi_file_is_name_set() will return true.
     */
    int ompi_file_set_name(ompi_file_t *file, char *name);

    /**
     * Back-end to MPI_FILE_CLOSE: destroy an ompi_file_t handle and
     * close the file.
     *
     * @param file Pointer to ompi_file_t
     *
     * @returns OMPI_SUCCESS Always.
     *
     * This is the preferred mechanism for freeing an ompi_file_t.
     * Although the main action that it performs is OBJ_RELEASE(), it
     * also does some additional handling for error checking, etc.
     */
    int ompi_file_close(ompi_file_t **file);

    /**
     * Tear down MPI_File handling.
     *
     * @retval OMPI_SUCCESS Always.
     *
     * Invoked during ompi_mpi_finalize().
     */
    int ompi_file_finalize(void);
    


/**
 * Check to see if an MPI_File handle is valid.
 *
 * @param file The MPI file handle
 *
 * @retval true If the file handle is not valid
 * @retval false If the file handle is valid
 *
 * This is a convenience function, mainly for error checking in
 * top-level MPI API functions.
 */
static inline bool ompi_file_invalid(ompi_file_t *file)
{
    return (NULL == file ||
            &ompi_mpi_file_null == file ||
            0 != (file->f_flags & OMPI_FILE_ISCLOSED));
}

#if defined(c_plusplus) || defined(__cplusplus)
}
#endif
#endif /* OMPI_FILE_H */