/*
 * Copyright (C) 2015 University of Chicago.
 * See COPYRIGHT notice in top-level directory.
 *
 */

#ifndef __DARSHAN_H
#define __DARSHAN_H

#include <unistd.h>
#include <sys/types.h>
#include <stdint.h>
#include <mpi.h>

#include "darshan-log-format.h"
#include "darshan-common.h"

/* macros for declaring wrapper functions and calling MPI routines
 * consistently regardless of whether static or dynamic linking is used
 */
#ifdef DARSHAN_PRELOAD

#include <dlfcn.h>
#include <stdlib.h>

#define DARSHAN_FORWARD_DECL(__func,__ret,__args) \
  __ret (*__real_ ## __func)__args = NULL

#define DARSHAN_DECL(__func) __func

#define DARSHAN_MPI_CALL(__func) __real_ ## __func

#define MAP_OR_FAIL(__func) \
    if (!(__real_ ## __func)) \
    { \
        __real_ ## __func = dlsym(RTLD_NEXT, #__func); \
        if(!(__real_ ## __func)) { \
           fprintf(stderr, "Darshan failed to map symbol: %s\n", #__func); \
           exit(1); \
       } \
    }

#else

#define DARSHAN_FORWARD_DECL(__name,__ret,__args) \
  extern __ret __real_ ## __name __args;

#define DARSHAN_DECL(__name) __wrap_ ## __name

#define DARSHAN_MPI_CALL(__func) __func

#define MAP_OR_FAIL(__func)

#endif

/* default number of records to attempt to store for each module */
#define DARSHAN_DEF_MOD_REC_COUNT 1024

/* module developers provide the following functions to darshan-core */
struct darshan_module_funcs
{
    /* perform any necessary pre-shutdown steps
     *
     * NOTE: this typically includes disabling wrapper functions so
     * darshan-core can shutdown in a consistent state.
     */
    void (*begin_shutdown)(void);
    /* retrieve module data to write to log file
     *
     * NOTE: module developers can use this function to run collective
     * MPI operations at shutdown time. Typically this functionality
     * has been used to reduce records shared globablly (given in the
     * 'shared_recs' array) into a single data record.
     */
    void (*get_output_data)(
        MPI_Comm mod_comm,  /* MPI communicator to run collectives with */
        darshan_record_id *shared_recs, /* list of shared data record ids */
        int shared_rec_count, /* count of shared data records */
        void** mod_buf, /* output parameter to save module buffer address */
        int* mod_buf_sz /* output parameter to save module buffer size */
    );
    /* shutdown module data structures */
    void (*shutdown)(void);
};

/*****************************************************
* darshan-core functions exported to darshan modules *
*****************************************************/

/* darshan_core_register_module()
 *
 * Register module identifier 'mod_id' with the darshan-core runtime
 * environment, allowing the module to store I/O characterization data.
 * 'funcs' is a pointer to a structure containing each of the function
 * pointers required by darshan-core to shut down the module. The function
 * returns the following integers passed in as pointers: 'rank' is the
 * MPI rank of the calling process, 'mod_mem_limit' is the maximum amount
 * of memory the module may use, and 'sys_mem_alignment' is the configured
 * memory alignment value Darshan was configured with.
 */
void darshan_core_register_module(
    darshan_module_id mod_id,
    struct darshan_module_funcs *funcs,
    int *inout_mod_buf_size,
    int *rank,
    int *sys_mem_alignment);

/* darshan_core_unregister_module()
 * 
 * Unregisters module identifier 'mod_id' with the darshan-core runtime,
 * removing the given module from the resulting I/O characterization log.
 */
void darshan_core_unregister_module(
    darshan_module_id mod_id);

/* darshan_core_gen_record_id()
 *
 *
 */
darshan_record_id darshan_core_gen_record_id(
    char *name);

/* darshan_core_register_record()
 *
 * Register a record with the darshan-core runtime, allowing it to be
 * properly tracked and (potentially) correlated with records from other
 * modules. 'name' is the the name of the Darshan record (e.g., the full
 * file path) and 'len' is the size of the name pointer (string length
 * for string names). 'mod_id' is the identifier of the calling module,
 * 'printable_flag' indicates whether the name is a string, and 
 * 'mod_limit_flag' is set if the calling module is out of memory (to
 * prevent darshan-core from creating new records and to just search
 * through existing records). 'rec_id' is an output pointer storing the
 * correspoing Darshan record identifier and 'file_alignment' is an output
 * pointer storing the file system alignment value for the given record.
 */
void *darshan_core_register_record(
    darshan_record_id rec_id,
    char *name,
    darshan_module_id mod_id,
    int rec_len,
    int *file_alignment);

/* darshan_core_wtime()
 *
 * Returns the elapsed time relative to (roughly) the start of
 * the application.
 */
double darshan_core_wtime(void);

/* darshan_core_excluded_path()
 *
 * Returns true (1) if the given file path is in Darshan's list of
 * excluded file paths, false (0) otherwise.
 */
int darshan_core_excluded_path(
    const char * path);

#endif /* __DARSHAN_H */