path: root/src/H5Oshared.c

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * 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.     *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*
 * Programmer:	Robb Matzke <matzke@llnl.gov>
 *		Wednesday, April  1, 1998
 *
 * Purpose:	Functions that operate on a shared message.  The shared
 *		message doesn't ever actually appear in the object header as
 *		a normal message.  Instead, if a message is shared, the
 *		H5O_FLAG_SHARED bit is set and the message body is that
 *		defined here for H5O_SHARED.  The message ID is the ID of the
 *		pointed-to message and the pointed-to message is stored in
 *		the global heap.
 */

#define H5F_PACKAGE	/*suppress error about including H5Fpkg	  */
#define H5O_PACKAGE	/*suppress error about including H5Opkg	  */


#include "H5private.h"		/* Generic Functions			*/
#include "H5Eprivate.h"		/* Error handling		  	*/
#include "H5Fpkg.h"             /* File access				*/
#include "H5Gprivate.h"		/* Groups				*/
#include "H5MMprivate.h"	/* Memory management			*/
#include "H5Opkg.h"             /* Object headers			*/

static void *H5O_shared_decode (H5F_t*, hid_t dxpl_id, const uint8_t*);
static herr_t H5O_shared_encode (H5F_t*, uint8_t*, const void*);
static void *H5O_shared_copy(const void *_mesg, void *_dest, unsigned update_flags);
static size_t H5O_shared_size (const H5F_t*, const void *_mesg);
static herr_t H5O_shared_delete(H5F_t *f, hid_t dxpl_id, const void *_mesg, hbool_t adj_link);
static herr_t H5O_shared_link(H5F_t *f, hid_t dxpl_id, const void *_mesg);
static herr_t H5O_shared_debug (H5F_t*, hid_t dxpl_id, const void*, FILE*, int, int);

/* This message derives from H5O message class */
const H5O_msg_class_t H5O_MSG_SHARED[1] = {{
    H5O_SHARED_ID,	    	/*message id number			*/
    "shared",		    	/*message name for debugging		*/
    sizeof(H5O_shared_t), 	/*native message size			*/
    H5O_shared_decode,	    	/*decode method				*/
    H5O_shared_encode,	    	/*encode method				*/
    H5O_shared_copy,		/*copy the native value			*/
    H5O_shared_size,	    	/*size method				*/
    NULL,		    	/*no reset method			*/
    NULL,		        /*no free method			*/
    H5O_shared_delete,		/*file delete method			*/
    H5O_shared_link,		/*link method				*/
    NULL,			/*get share method			*/
    NULL, 			/*set share method			*/
    H5O_shared_debug	    	/*debug method				*/
}};

/* Old version, with full symbol table entry as link for object header sharing */
#define H5O_SHARED_VERSION_1	1

/* New version, with just address of object as link for object header sharing */
#define H5O_SHARED_VERSION	2


/*-------------------------------------------------------------------------
 * Function:	H5O_shared_read
 *
 * Purpose:	Reads a message referred to by a shared message.
 *
 * Return:	Success:	Ptr to message in native format.  The message
 *				should be freed by calling H5O_reset().  If
 *				MESG is a null pointer then the caller should
 *				also call H5MM_xfree() on the return value
 *				after calling H5O_reset().
 *
 *		Failure:	NULL
 *
 * Programmer:	Quincey Koziol
 *		koziol@ncsa.uiuc.edu
 *		Sep 24 2003
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
void *
H5O_shared_read(H5F_t *f, hid_t dxpl_id, H5O_shared_t *shared, const H5O_msg_class_t *type, void *mesg)
{
    void *ret_value = NULL;     /* Return value */

    FUNC_ENTER_NOAPI_NOINIT(H5O_shared_read)

    /* check args */
    HDassert(f);
    HDassert(shared);
    HDassert(type);

    /* Get the shared message */
    ret_value = H5O_read_real(&(shared->ent), type, 0, mesg, dxpl_id);
    if(type->set_share && (type->set_share)(f, ret_value, shared) < 0)
        HGOTO_ERROR (H5E_OHDR, H5E_CANTINIT, NULL, "unable to set sharing information")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_shared_read() */


/*-------------------------------------------------------------------------
 * Function:	H5O_shared_link_adj
 *
 * Purpose:	Changes the link count for the object referenced by a shared
 *              message.
 *
 * Return:	Success:	New link count
 *
 *		Failure:	Negative
 *
 * Programmer:	Quincey Koziol
 *		koziol@ncsa.uiuc.edu
 *		Sep 26 2003
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static int
H5O_shared_link_adj(H5F_t *f, hid_t dxpl_id, const H5O_shared_t *shared, int adjust)
{
    int ret_value;     /* Return value */

    FUNC_ENTER_NOAPI_NOINIT(H5O_shared_link_adj)

    /* check args */
    HDassert(f);
    HDassert(shared);

    /*
     * The shared message is stored in some other object header.
     * The other object header must be in the same file as the
     * new object header. Adjust the reference count on that
     * object header.
     */
    if(shared->ent.file->shared != f->shared)
        HGOTO_ERROR(H5E_OHDR, H5E_LINK, FAIL, "interfile hard links are not allowed")
    if((ret_value = H5O_link (&(shared->ent), adjust, dxpl_id)) < 0)
        HGOTO_ERROR(H5E_OHDR, H5E_LINK, FAIL, "unable to adjust shared object link count")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_shared_link_adj() */


/*-------------------------------------------------------------------------
 * Function:	H5O_shared_decode
 *
 * Purpose:	Decodes a shared object message and returns it.
 *
 * Return:	Success:	Ptr to a new shared object message.
 *
 *		Failure:	NULL
 *
 * Programmer:	Robb Matzke
 *              Thursday, April  2, 1998
 *
 * Modifications:
 *	Robb Matzke, 1998-07-20
 *	Added a version number to the beginning of the message.
 *-------------------------------------------------------------------------
 */
static void *
H5O_shared_decode(H5F_t *f, hid_t UNUSED dxpl_id, const uint8_t *buf)
{
    H5O_shared_t	*mesg = NULL;
    unsigned		flags, version;
    void                *ret_value;     /* Return value */

    FUNC_ENTER_NOAPI_NOINIT(H5O_shared_decode)

    /* Check args */
    HDassert(f);
    HDassert(buf);

    /* Decode */
    if(NULL == (mesg = H5MM_calloc (sizeof(H5O_shared_t))))
	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")

    /* Version */
    version = *buf++;
    if(version != H5O_SHARED_VERSION_1 && version != H5O_SHARED_VERSION)
	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, NULL, "bad version number for shared object message")

    /* Get the shared information flags */
    flags = *buf++;             /* Unused currently */

    /* Skip reserved bytes (for version 1) */
    if(version == H5O_SHARED_VERSION_1)
        buf += 6;

    /* Body */
    if(version == H5O_SHARED_VERSION_1)
        H5G_ent_decode(f, &buf, &(mesg->ent));
    else {
        HDassert(version == H5O_SHARED_VERSION);
        H5F_addr_decode(f, &buf, &(mesg->ent.header));
        mesg->ent.file = f;
    } /* end else */

    /* Set return value */
    ret_value = mesg;

done:
    if(ret_value==NULL) {
        if(mesg!=NULL)
            H5MM_xfree(mesg);
    } /* end if */

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5O_shared_decode() */


/*-------------------------------------------------------------------------
 * Function:	H5O_shared_encode
 *
 * Purpose:	Encodes message _MESG into buffer BUF.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *              Thursday, April  2, 1998
 *
 * Modifications:
 *	Robb Matzke, 1998-07-20
 *	Added a version number to the beginning of the message.
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5O_shared_encode (H5F_t *f, uint8_t *buf/*out*/, const void *_mesg)
{
    const H5O_shared_t	*mesg = (const H5O_shared_t *)_mesg;

    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5O_shared_encode)

    /* Check args */
    HDassert(f);
    HDassert(buf);
    HDassert(mesg);

    /* Encode */
    *buf++ = H5O_SHARED_VERSION;
    *buf++ = 0; /* No flags currently */
    H5F_addr_encode(f, &buf, mesg->ent.header);

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5O_shared_encode() */


/*-------------------------------------------------------------------------
 * Function:	H5O_shared_copy
 *
 * Purpose:	Copies a message from _MESG to _DEST, allocating _DEST if
 *		necessary.
 *
 * Return:	Success:	Ptr to _DEST
 *
 *		Failure:	NULL
 *
 * Programmer:	Quincey Koziol
 *		koziol@ncsa.uiuc.edu
 *		Sep 26 2003
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static void *
H5O_shared_copy(const void *_mesg, void *_dest, unsigned UNUSED update_flags)
{
    const H5O_shared_t  *mesg = (const H5O_shared_t *) _mesg;
    H5O_shared_t	*dest = (H5O_shared_t *) _dest;
    void        *ret_value;     /* Return value */

    FUNC_ENTER_NOAPI_NOINIT(H5O_shared_copy);

    /* check args */
    assert(mesg);
    if (!dest && NULL==(dest = H5MM_malloc (sizeof(H5O_shared_t))))
        HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed");

    /* copy */
    *dest = *mesg;

    /* Set return value */
    ret_value=dest;

done:
    FUNC_LEAVE_NOAPI(ret_value);
} /* end H5O_shared_copy() */


/*-------------------------------------------------------------------------
 * Function:	H5O_shared_size
 *
 * Purpose:	Returns the length of a shared object message.
 *
 * Return:	Success:	Length
 *
 *		Failure:	0
 *
 * Programmer:	Robb Matzke
 *              Thursday, April  2, 1998
 *
 *-------------------------------------------------------------------------
 */
static size_t
H5O_shared_size (const H5F_t *f, const void UNUSED *_mesg)
{
    size_t	ret_value;

    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5O_shared_size);

    ret_value = 1 +			/*version			*/
            1 +				/*the flags field		*/
            H5F_SIZEOF_ADDR(f);		/*sharing by another obj hdr	*/

    FUNC_LEAVE_NOAPI(ret_value);
}


/*-------------------------------------------------------------------------
 * Function:    H5O_shared_delete
 *
 * Purpose:     Free file space referenced by message
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Quincey Koziol
 *              Friday, September 26, 2003
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5O_shared_delete(H5F_t *f, hid_t dxpl_id, const void *_mesg, hbool_t adj_link)
{
    const H5O_shared_t       *shared = (const H5O_shared_t *) _mesg;
    herr_t ret_value=SUCCEED;   /* Return value */

    FUNC_ENTER_NOAPI_NOINIT(H5O_shared_delete);

    /* check args */
    assert(f);
    assert(shared);

    /* Decrement the reference count on the shared object, if requested */
    if(adj_link)
        if(H5O_shared_link_adj(f, dxpl_id, shared, -1)<0)
            HGOTO_ERROR (H5E_OHDR, H5E_LINK, FAIL, "unable to adjust shared object link count")

done:
    FUNC_LEAVE_NOAPI(ret_value);
} /* end H5O_shared_delete() */


/*-------------------------------------------------------------------------
 * Function:    H5O_shared_link
 *
 * Purpose:     Increment reference count on any objects referenced by
 *              message
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Quincey Koziol
 *              Friday, September 26, 2003
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5O_shared_link(H5F_t *f, hid_t dxpl_id, const void *_mesg)
{
    const H5O_shared_t       *shared = (const H5O_shared_t *) _mesg;
    herr_t ret_value=SUCCEED;   /* Return value */

    FUNC_ENTER_NOAPI_NOINIT(H5O_shared_link);

    /* check args */
    assert(f);
    assert(shared);

    /* Decrement the reference count on the shared object */
    if(H5O_shared_link_adj(f,dxpl_id,shared,1)<0)
        HGOTO_ERROR (H5E_OHDR, H5E_LINK, FAIL, "unable to adjust shared object link count");

done:
    FUNC_LEAVE_NOAPI(ret_value);
} /* end H5O_shared_link() */


/*-------------------------------------------------------------------------
 * Function:	H5O_shared_debug
 *
 * Purpose:	Prints debugging info for the message
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *              Thursday, April  2, 1998
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5O_shared_debug (H5F_t UNUSED *f, hid_t dxpl_id, const void *_mesg,
		  FILE *stream, int indent, int fwidth)
{
    const H5O_shared_t	*mesg = (const H5O_shared_t *)_mesg;

    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5O_shared_debug)

    /* Check args */
    HDassert(f);
    HDassert(mesg);
    HDassert(stream);
    HDassert(indent >= 0);
    HDassert(fwidth >= 0);

    HDfprintf(stream, "%*s%-*s %s\n", indent, "", fwidth,
               "Sharing method",
               "Obj Hdr");
    H5G_ent_debug (f, dxpl_id, &(mesg->ent), stream, indent, fwidth,
                   HADDR_UNDEF);

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5O_shared_debug() */