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mirror of https://github.com/xcat2/xNBA.git synced 2024-12-24 04:01:33 +00:00

Add (and use) generic reference counter, to improve signal:noise ratio

in code defining reference-counted objects.
This commit is contained in:
Michael Brown 2007-04-29 23:53:39 +00:00
parent 36bfb6edbb
commit d40761d725
8 changed files with 128 additions and 58 deletions

View File

@ -16,7 +16,6 @@
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <assert.h>
#include <gpxe/interface.h>
/** @file
@ -25,30 +24,6 @@
*
*/
/**
* Obtain reference to interface
*
* @v intf Interface
* @ret intf Interface
*
* Increases the reference count on the interface.
*/
static struct interface * intf_get ( struct interface *intf ) {
intf->refcnt ( intf, +1 );
return intf;
}
/**
* Drop reference to interface
*
* @v intf Interface
*
* Decreases the reference count on the interface.
*/
static void intf_put ( struct interface *intf ) {
intf->refcnt ( intf, -1 );
}
/**
* Plug an interface into a new destination interface
*
@ -63,19 +38,7 @@ static void intf_put ( struct interface *intf ) {
* interface into a null interface.
*/
void plug ( struct interface *intf, struct interface *dest ) {
intf_put ( intf->dest );
intf->dest = intf_get ( dest );
}
/**
* Null update reference count
*
* @v intf Interface
* @v delta Change to apply to reference count
*
* Use this as the refcnt() method for an interface that does not need
* to support reference counting.
*/
void null_refcnt ( struct interface *intf __unused, int delta __unused ) {
/* Do nothing */
ref_put ( intf->refcnt );
ref_get ( dest->refcnt );
intf->dest = dest;
}

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@ -71,7 +71,7 @@ struct job_interface_operations null_job_ops = {
struct job_interface null_job = {
.intf = {
.dest = &null_job.intf,
.refcnt = null_refcnt,
.refcnt = NULL,
},
.op = &null_job_ops,
};

73
src/core/refcnt.c Normal file
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@ -0,0 +1,73 @@
/*
* Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <stdlib.h>
#include <gpxe/refcnt.h>
/** @file
*
* Reference counting
*
*/
/**
* Increment reference count
*
* @v refcnt Reference counter, or NULL
*
* If @c refcnt is NULL, no action is taken.
*/
void ref_get ( struct refcnt *refcnt ) {
if ( ! refcnt )
return;
refcnt->refcnt++;
DBGC ( refcnt, "REFCNT %p incremented to %d\n",
refcnt, refcnt->refcnt );
}
/**
* Decrement reference count
*
* @v refcnt Reference counter, or NULL
*
* If the reference count decreases below zero, the object's free()
* method will be called.
*
* If @c refcnt is NULL, no action is taken.
*/
void ref_put ( struct refcnt *refcnt ) {
if ( ! refcnt )
return;
refcnt->refcnt--;
DBGC ( refcnt, "REFCNT %p decremented to %d\n",
refcnt, refcnt->refcnt );
if ( refcnt->refcnt >= 0 )
return;
if ( refcnt->free ) {
refcnt->free ( refcnt );
} else {
free ( refcnt );
}
}

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@ -230,7 +230,7 @@ struct xfer_interface_operations null_xfer_ops = {
struct xfer_interface null_xfer = {
.intf = {
.dest = &null_xfer.intf,
.refcnt = null_refcnt,
.refcnt = NULL,
},
.op = &null_xfer_ops,
};

View File

@ -7,6 +7,8 @@
*
*/
#include <gpxe/refcnt.h>
/** An object communication interface */
struct interface {
/** Destination interface
@ -18,19 +20,14 @@ struct interface {
* unplugged, it should point to a null interface.
*/
struct interface *dest;
/** Update reference count
/** Reference counter
*
* @v intf Interface
* @v delta Change to apply to reference count
*
* This method updates the reference count for the object
* containing the interface.
* If this interface is not part of a reference-counted
* object, this field may be NULL.
*/
void ( * refcnt ) ( struct interface *intf, int delta );
struct refcnt *refcnt;
};
extern void plug ( struct interface *intf, struct interface *dest );
extern void null_refcnt ( struct interface *intf, int delta );
#endif /* _GPXE_INTERFACE_H */

View File

@ -76,12 +76,11 @@ extern void ignore_progress ( struct job_interface *job,
*
* @v job Job control interface
* @v op Job control interface operations
* @v refcnt Job control interface reference counting method
* @v refcnt Containing object reference counter, or NULL
*/
static inline void job_init ( struct job_interface *job,
struct job_interface_operations *op,
void ( * refcnt ) ( struct interface *intf,
int delta ) ) {
struct job_interface_operations *op,
struct refcnt *refcnt ) {
job->intf.dest = &null_job.intf;
job->intf.refcnt = refcnt;
job->op = op;

39
src/include/gpxe/refcnt.h Normal file
View File

@ -0,0 +1,39 @@
#ifndef _GPXE_REFCNT_H
#define _GPXE_REFCNT_H
/** @file
*
* Reference counting
*
*/
/**
* A reference counter
*
* This data structure is designed to be embedded within a
* reference-counted object.
*/
struct refcnt {
/** Current reference count
*
* When this count is decremented below zero, the free()
* method will be called.
*/
int refcnt;
/** Free containing object
*
* This method is called when the reference count is
* decremented below zero.
*
* If this method is left NULL, the standard library free()
* function will be called. The upshot of this is that you
* may omit the free() method if the @c refcnt object is the
* first element of your reference-counted struct.
*/
void ( * free ) ( struct refcnt *refcnt );
};
extern void ref_get ( struct refcnt *refcnt );
extern void ref_put ( struct refcnt *refcnt );
#endif /* _GPXE_REFCNT_H */

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@ -114,12 +114,11 @@ extern int ignore_deliver_raw ( struct xfer_interface *xfer,
*
* @v xfer Data transfer interface
* @v op Data transfer interface operations
* @v refcnt Data transfer interface reference counting method
* @v refcnt Containing object reference counter, or NULL
*/
static inline void xfer_init ( struct xfer_interface *xfer,
struct xfer_interface_operations *op,
void ( * refcnt ) ( struct interface *intf,
int delta ) ) {
struct refcnt *refcnt ) {
xfer->intf.dest = &null_xfer.intf;
xfer->intf.refcnt = refcnt;
xfer->op = op;