/* -*- Mode: C; c-basic-offset:4 ; -*- */
/* 
 *
 *   Copyright (C) 1997 University of Chicago. 
 *   See COPYRIGHT notice in top-level directory.
 */

#include "mpioimpl.h"

#ifdef HAVE_WEAK_SYMBOLS

#if defined(HAVE_PRAGMA_WEAK)
#pragma weak MPI_File_iread_shared = PMPI_File_iread_shared
#elif defined(HAVE_PRAGMA_HP_SEC_DEF)
#pragma _HP_SECONDARY_DEF PMPI_File_iread_shared MPI_File_iread_shared
#elif defined(HAVE_PRAGMA_CRI_DUP)
#pragma _CRI duplicate MPI_File_iread_shared as PMPI_File_iread_shared
/* end of weak pragmas */
#endif

/* Include mapping from MPI->PMPI */
#define MPIO_BUILD_PROFILING
#include "mpioprof.h"
#endif

/*@
    MPI_File_iread_shared - Nonblocking read using shared file pointer

Input Parameters:
. fh - file handle (handle)
. count - number of elements in buffer (nonnegative integer)
. datatype - datatype of each buffer element (handle)

Output Parameters:
. buf - initial address of buffer (choice)
. request - request object (handle)

.N fortran
@*/
#ifdef HAVE_MPI_GREQUEST
#include "mpiu_greq.h"

#if defined(HAVE_WINDOWS_H) && defined(USE_WIN_THREADED_IO)
typedef struct iread_shared_args
{
    MPI_File file;
    void *buf;
    int count;
    MPI_Datatype datatype;
    MPIO_Request request;
    MPI_Status *status;
} iread_shared_args;

static DWORD WINAPI iread_shared_thread(LPVOID lpParameter)
{
    int error_code;
    iread_shared_args *args = (iread_shared_args *)lpParameter;

    error_code = MPI_File_read_shared(args->file, args->buf, args->count, args->datatype, args->status);
    /* ROMIO-1 doesn't do anything with status.MPI_ERROR */
    args->status->MPI_ERROR = error_code;

    MPI_Grequest_complete(args->request);
    ADIOI_Free(args);
    return 0;
}
#endif

int MPI_File_iread_shared(MPI_File mpi_fh, void *buf, int count, 
			  MPI_Datatype datatype, MPIO_Request *request)
{
    int error_code=MPI_SUCCESS;
    ADIO_File fh;
    MPI_Status *status;
#if defined(HAVE_WINDOWS_H) && defined(USE_WIN_THREADED_IO)
    iread_shared_args *args;
    HANDLE hThread;
#endif

    MPIU_THREAD_SINGLE_CS_ENTER("io");
    MPIR_Nest_incr();

    fh = MPIO_File_resolve(mpi_fh);

    status = (MPI_Status *) ADIOI_Malloc(sizeof(MPI_Status));

#if defined(HAVE_WINDOWS_H) && defined(USE_WIN_THREADED_IO)
    /* kick off the request */
    MPI_Grequest_start(MPIU_Greq_query_fn, MPIU_Greq_free_fn, 
	MPIU_Greq_cancel_fn, status, request);

    args = (iread_shared_args*) ADIOI_Malloc(sizeof(iread_shared_args));
    args->file = mpi_fh;
    args->buf = buf;
    args->count = count;
    args->datatype = datatype;
    args->status = status;
    args->request = *request;
    hThread = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)iread_shared_thread, args, 0, NULL);
    if (hThread == NULL)
    {
	error_code = GetLastError();
	error_code = MPIO_Err_create_code(MPI_SUCCESS, MPIR_ERR_RECOVERABLE,
	    "MPI_File_iread_shared", __LINE__, MPI_ERR_OTHER,
	    "**fail", "**fail %d", error_code);
	error_code = MPIO_Err_return_file(fh, error_code);
	return error_code;
    }
    CloseHandle(hThread);

#else

    /* for now, no threads or anything fancy. 
    * just call the blocking version */
    error_code = MPI_File_read_shared(mpi_fh, buf, count, datatype,
	status); 
    /* ROMIO-1 doesn't do anything with status.MPI_ERROR */
    status->MPI_ERROR = error_code;

    /* --BEGIN ERROR HANDLING-- */
    if (error_code != MPI_SUCCESS)
	error_code = MPIO_Err_return_file(mpi_fh, error_code);
    /* --END ERROR HANDLING-- */

    /* kick off the request */
    MPI_Grequest_start(MPIU_Greq_query_fn, MPIU_Greq_free_fn, 
	MPIU_Greq_cancel_fn, status, request);

    /* but we did all the work already */
    MPI_Grequest_complete(*request);
    /* passed the buck to the blocking version...*/
#endif

    MPIR_Nest_decr();
    MPIU_THREAD_SINGLE_CS_EXIT("io");
    return error_code;
}
#else
int MPI_File_iread_shared(MPI_File mpi_fh, void *buf, int count, 
                          MPI_Datatype datatype, MPIO_Request *request)
{
    int error_code, bufsize, buftype_is_contig, filetype_is_contig;
    ADIO_File fh;
    static char myname[] = "MPI_FILE_IREAD_SHARED";
    int datatype_size, incr;
    ADIO_Status status;
    ADIO_Offset off, shared_fp;

    MPIU_THREAD_SINGLE_CS_ENTER("io");
    MPIR_Nest_incr();

    fh = MPIO_File_resolve(mpi_fh);

    /* --BEGIN ERROR HANDLING-- */
    MPIO_CHECK_FILE_HANDLE(fh, myname, error_code);
    MPIO_CHECK_COUNT(fh, count, myname, error_code);
    MPIO_CHECK_DATATYPE(fh, datatype, myname, error_code);
    /* --END ERROR HANDLING-- */

    MPI_Type_size(datatype, &datatype_size);

    /* --BEGIN ERROR HANDLING-- */
    MPIO_CHECK_INTEGRAL_ETYPE(fh, count, datatype_size, myname, error_code);
    MPIO_CHECK_FS_SUPPORTS_SHARED(fh, myname, error_code);
    /* --END ERROR HANDLING-- */

    ADIOI_Datatype_iscontig(datatype, &buftype_is_contig);
    ADIOI_Datatype_iscontig(fh->filetype, &filetype_is_contig);

    ADIOI_TEST_DEFERRED(fh, myname, &error_code);

    incr = (count*datatype_size)/fh->etype_size;
    ADIO_Get_shared_fp(fh, incr, &shared_fp, &error_code);

    /* --BEGIN ERROR HANDLING-- */
    if (error_code != MPI_SUCCESS)
    {
	/* note: ADIO_Get_shared_fp should have set up error code already? */
	MPIO_Err_return_file(fh, error_code);
    }
    /* --END ERROR HANDLING-- */

    if (buftype_is_contig && filetype_is_contig)
    {
    /* convert count and shared_fp to bytes */
	bufsize = datatype_size * count;
	off = fh->disp + fh->etype_size * shared_fp;
        if (!(fh->atomicity))
	{
	    ADIO_IreadContig(fh, buf, count, datatype, ADIO_EXPLICIT_OFFSET,
			off, request, &error_code);
	}
        else
	{
            /* to maintain strict atomicity semantics with other concurrent
              operations, lock (exclusive) and call blocking routine */

            *request = ADIOI_Malloc_request();
            (*request)->optype = ADIOI_READ;
            (*request)->fd = fh;
            (*request)->datatype = datatype;
            (*request)->queued = 0;
	    (*request)->handle = 0;

            if (fh->file_system != ADIO_NFS)
	    {
                ADIOI_WRITE_LOCK(fh, off, SEEK_SET, bufsize);
	    }

            ADIO_ReadContig(fh, buf, count, datatype, ADIO_EXPLICIT_OFFSET,
			    off, &status, &error_code);  

            if (fh->file_system != ADIO_NFS)
	    {
                ADIOI_UNLOCK(fh, off, SEEK_SET, bufsize);
	    }

            fh->async_count++;
            /* status info. must be linked to the request structure, so that
               it can be accessed later from a wait */
        }
    }
    else
    {
	ADIO_IreadStrided(fh, buf, count, datatype, ADIO_EXPLICIT_OFFSET,
			   shared_fp, request, &error_code);
    }

    /* --BEGIN ERROR HANDLING-- */
    if (error_code != MPI_SUCCESS)
	error_code = MPIO_Err_return_file(fh, error_code);
    /* --END ERROR HANDLING-- */

fn_exit:
    MPIR_Nest_decr();
    MPIU_THREAD_SINGLE_CS_EXIT("io");
    return error_code;
}
#endif
