/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * Copyright by the Board of Trustees of the University of Illinois.         *
 * All rights reserved.                                                      *
 *                                                                           *
 * This file is part of HDF5.  The full HDF5 copyright notice, including     *
 * terms governing use, modification, and redistribution, is contained in    *
 * the files COPYING and Copyright.html.  COPYING can be found at the root   *
 * of the source code distribution tree; Copyright.html can be found at the  *
 * root level of an installed copy of the electronic HDF5 document set and   *
 * is linked from the top-level documents page.  It can also be found at     *
 * http://hdfgroup.org/HDF5/doc/Copyright.html.  If you do not have          *
 * access to either file, you may request a copy from help@hdfgroup.org.     *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

#include "H5Fmodule.h"          /* This source code file is part of the H5F module */

/* Packages needed by this file... */
#include "H5private.h"		/* Generic Functions			*/
#include "H5Eprivate.h"		/* Error handling		  	*/
#include "H5Fpkg.h"             /* File access				*/
#include "H5FDprivate.h"	/* File drivers				*/
#include "H5FLprivate.h"	/* Free lists                           */

/* PRIVATE TYPEDEFS */

/* Struct for tracking "shared" file structs */
typedef struct H5F_sfile_node_t {
    H5F_file_t *shared;                 /* Pointer to "shared" file struct */
    struct H5F_sfile_node_t *next;      /* Pointer to next node */
} H5F_sfile_node_t;

/* PRIVATE PROTOTYPES */

/* PRIVATE VARIABLES */

/* Declare a free list to manage the H5F_sfile_node_t struct */
H5FL_DEFINE_STATIC(H5F_sfile_node_t);

/* Declare a local variable to track the shared file information */
H5F_sfile_node_t *H5F_sfile_head_g = NULL;


/*-------------------------------------------------------------------------
 * Function:	H5F_sfile_assert_num
 *
 * Purpose:	Sanity checking that shared file list is empty
 *
 * Return:	none (void)
 *
 * Programmer:	Quincey Koziol
 *              Monday, July 25, 2005
 *
 *-------------------------------------------------------------------------
 */
void
H5F_sfile_assert_num(unsigned n)
{
    FUNC_ENTER_NOAPI_NOINIT_NOERR

    if(n == 0) {
        /* Sanity checking */
        HDassert(H5F_sfile_head_g == NULL);
    } /* end if */
    else {
        unsigned count;                 /* Number of open shared files */
        H5F_sfile_node_t *curr;         /* Current shared file node */

        /* Iterate through low-level files for matching low-level file info */
        curr = H5F_sfile_head_g;
        count = 0;
        while(curr) {
            /* Increment # of open shared file structs */
            count++;

            /* Advance to next shared file node */
            curr = curr->next;
        } /* end while */

        /* Sanity checking */
        HDassert(count == n);
    } /* end else */

    FUNC_LEAVE_NOAPI_VOID
} /* H5F_sfile_assert_num() */


/*-------------------------------------------------------------------------
 * Function:	H5F_sfile_add
 *
 * Purpose:	Add a "shared" file struct to the list of open files
 *
 * Return:	SUCCEED/FAIL
 *
 * Programmer:	Quincey Koziol
 *              Monday, July 18, 2005
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5F_sfile_add(H5F_file_t *shared)
{
    H5F_sfile_node_t *new_shared;              /* New shared file node */
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    /* Sanity check */
    HDassert(shared);

    /* Allocate new shared file node */
    if (NULL == (new_shared = H5FL_CALLOC(H5F_sfile_node_t)))
	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")

    /* Set shared file value */
    new_shared->shared = shared;

    /* Prepend to list of shared files open */
    new_shared->next = H5F_sfile_head_g;
    H5F_sfile_head_g = new_shared;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5F_sfile_add() */


/*-------------------------------------------------------------------------
 * Function:	H5F_sfile_search
 *
 * Purpose:	Search for a "shared" file with low-level file info that
 *              matches
 *
 * Return:	Non-NULL on success / NULL on failure
 *
 * Programmer:	Quincey Koziol
 *              Monday, July 18, 2005
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
H5F_file_t *
H5F_sfile_search(H5FD_t *lf)
{
    H5F_sfile_node_t *curr;             /* Current shared file node */
    H5F_file_t *ret_value = NULL;       /* Return value */

    FUNC_ENTER_NOAPI_NOINIT_NOERR

    /* Sanity check */
    HDassert(lf);

    /* Iterate through low-level files for matching low-level file info */
    curr = H5F_sfile_head_g;
    while(curr) {
        /* Check for match */
        if(0==H5FD_cmp(curr->shared->lf, lf))
            HGOTO_DONE(curr->shared)

        /* Advance to next shared file node */
        curr = curr->next;
    } /* end while */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5F_sfile_search() */


/*-------------------------------------------------------------------------
 * Function:	H5F_sfile_remove
 *
 * Purpose:	Remove a "shared" file struct from the list of open files
 *
 * Return:	SUCCEED/FAIL
 *
 * Programmer:	Quincey Koziol
 *              Monday, July 18, 2005
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5F_sfile_remove(H5F_file_t *shared)
{
    H5F_sfile_node_t *curr;             /* Current shared file node */
    H5F_sfile_node_t *last;             /* Last shared file node */
    herr_t ret_value = SUCCEED;         /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    /* Sanity check */
    HDassert(shared);

    /* Locate shared file node with correct shared file */
    last = NULL;
    curr = H5F_sfile_head_g;
    while(curr && curr->shared != shared) {
        /* Advance to next node */
        last = curr;
        curr = curr->next;
    } /* end while */

    /* Indicate error if the node wasn't found */
    if(curr == NULL)
	HGOTO_ERROR(H5E_FILE, H5E_NOTFOUND, FAIL, "can't find shared file info")

    /* Remove node found from list */
    if(last != NULL)
        /* Removing middle or tail node in list */
        last->next = curr->next;
    else
        /* Removing head node in list */
        H5F_sfile_head_g = curr->next;

    /* Release the shared file node struct */
    /* (the shared file info itself is freed elsewhere) */
    curr = H5FL_FREE(H5F_sfile_node_t, curr);

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5F_sfile_remove() */

