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mirror of https://github.com/xcat2/xNBA.git synced 2024-12-23 19:51:46 +00:00

Do not hold self-references. This then avoids the problem of having to

ensure that we only drop our self-reference exactly once.

To maintain the guarantee that an object won't go out of scope
unexpectedly while one of its event handlers is being called, the
event-calling functions now automatically obtain and drop extra
references.
This commit is contained in:
Michael Brown 2007-05-15 16:53:46 +00:00
parent 5471bfbbbe
commit b1755462ab
7 changed files with 96 additions and 38 deletions

View File

@ -50,6 +50,19 @@ struct downloader {
int ( * register_image ) ( struct image *image );
};
/**
* Free downloader object
*
* @v refcnt Downloader reference counter
*/
static void downloader_free ( struct refcnt *refcnt ) {
struct downloader *downloader =
container_of ( refcnt, struct downloader, refcnt );
image_put ( downloader->image );
free ( downloader );
}
/**
* Terminate download
*
@ -63,12 +76,8 @@ static void downloader_finished ( struct downloader *downloader, int rc ) {
xfer_nullify ( &downloader->xfer );
/* Free resources and close interfaces */
image_put ( downloader->image );
xfer_close ( &downloader->xfer, rc );
job_done ( &downloader->job, rc );
/* Drop reference to self */
ref_put ( &downloader->refcnt );
}
/**
@ -267,6 +276,7 @@ int create_downloader ( struct job_interface *job, const char *uri_string,
if ( ! downloader )
return -ENOMEM;
memset ( downloader, 0, sizeof ( *downloader ) );
downloader->refcnt.free = downloader_free;
job_init ( &downloader->job, &downloader_job_operations,
&downloader->refcnt );
xfer_init ( &downloader->xfer, &downloader_xfer_operations,
@ -279,11 +289,13 @@ int create_downloader ( struct job_interface *job, const char *uri_string,
uri_string ) ) != 0 )
goto err;
/* Attach parent interface and return */
/* Attach parent interface, mortalise self, and return */
job_plug_plug ( &downloader->job, job );
ref_put ( &downloader->refcnt );
return 0;
err:
downloader_finished ( downloader, rc );
ref_put ( &downloader->refcnt );
return rc;
}

View File

@ -22,7 +22,6 @@ static const char hw_msg[] = "Hello world!\n";
static void hw_finished ( struct hw *hw, int rc ) {
xfer_nullify ( &hw->xfer );
xfer_close ( &hw->xfer, rc );
ref_put ( &hw->refcnt );
}
static void hw_xfer_close ( struct xfer_interface *xfer, int rc ) {
@ -31,13 +30,14 @@ static void hw_xfer_close ( struct xfer_interface *xfer, int rc ) {
hw_finished ( hw, rc );
}
static int hw_xfer_request ( struct xfer_interface *xfer, off_t start __unused,
int whence __unused, size_t len __unused ) {
static void hw_xfer_request ( struct xfer_interface *xfer,
off_t start __unused, int whence __unused,
size_t len __unused ) {
struct hw *hw = container_of ( xfer, struct hw, xfer );
int rc;
xfer_deliver_raw ( xfer, hw_msg, sizeof ( hw_msg ) );
hw_finished ( hw, 0 );
return 0;
rc = xfer_deliver_raw ( xfer, hw_msg, sizeof ( hw_msg ) );
hw_finished ( hw, rc );
}
static struct xfer_interface_operations hw_xfer_operations = {
@ -52,13 +52,16 @@ static struct xfer_interface_operations hw_xfer_operations = {
static int hw_open ( struct xfer_interface *xfer, struct uri *uri __unused ) {
struct hw *hw;
/* Allocate and initialise structure */
hw = malloc ( sizeof ( *hw ) );
if ( ! hw )
return -ENOMEM;
memset ( hw, 0, sizeof ( *hw ) );
xfer_init ( &hw->xfer, &hw_xfer_operations, &hw->refcnt );
/* Attach parent interface, mortalise self, and return */
xfer_plug_plug ( &hw->xfer, xfer );
ref_put ( &hw->refcnt );
return 0;
}

View File

@ -27,10 +27,11 @@
*/
void job_done ( struct job_interface *job, int rc ) {
struct job_interface *dest = job_dest ( job );
struct job_interface *dest = job_get_dest ( job );
dest->op->done ( dest, rc );
job_unplug ( job );
job_put ( dest );
}
/****************************************************************************

View File

@ -33,10 +33,11 @@
* @v rc Reason for close
*/
void xfer_close ( struct xfer_interface *xfer, int rc ) {
struct xfer_interface *dest = xfer_dest ( xfer );
struct xfer_interface *dest = xfer_get_dest ( xfer );
dest->op->close ( dest, rc );
xfer_unplug ( xfer );
xfer_put ( dest );
}
/**
@ -48,9 +49,12 @@ void xfer_close ( struct xfer_interface *xfer, int rc ) {
* @ret rc Return status code
*/
int xfer_vredirect ( struct xfer_interface *xfer, int type, va_list args ) {
struct xfer_interface *dest = xfer_dest ( xfer );
struct xfer_interface *dest = xfer_get_dest ( xfer );
int rc;
return dest->op->vredirect ( dest, type, args );
rc = dest->op->vredirect ( dest, type, args );
xfer_put ( dest );
return rc;
}
/**
@ -82,9 +86,12 @@ int xfer_redirect ( struct xfer_interface *xfer, int type, ... ) {
*/
int xfer_request ( struct xfer_interface *xfer, off_t offset, int whence,
size_t len ) {
struct xfer_interface *dest = xfer_dest ( xfer );
struct xfer_interface *dest = xfer_get_dest ( xfer );
int rc;
return dest->op->request ( dest, offset, whence, len );
rc = dest->op->request ( dest, offset, whence, len );
xfer_put ( dest );
return rc;
}
/**
@ -106,9 +113,12 @@ int xfer_request_all ( struct xfer_interface *xfer ) {
* @ret rc Return status code
*/
int xfer_seek ( struct xfer_interface *xfer, off_t offset, int whence ) {
struct xfer_interface *dest = xfer_dest ( xfer );
struct xfer_interface *dest = xfer_get_dest ( xfer );
int rc;
return dest->op->seek ( dest, offset, whence );
rc = dest->op->seek ( dest, offset, whence );
xfer_put ( dest );
return rc;
}
/**
@ -119,9 +129,12 @@ int xfer_seek ( struct xfer_interface *xfer, off_t offset, int whence ) {
* @ret iobuf I/O buffer
*/
struct io_buffer * xfer_alloc_iob ( struct xfer_interface *xfer, size_t len ) {
struct xfer_interface *dest = xfer_dest ( xfer );
struct xfer_interface *dest = xfer_get_dest ( xfer );
struct io_buffer *iobuf;
return dest->op->alloc_iob ( dest, len );
iobuf = dest->op->alloc_iob ( dest, len );
xfer_put ( dest );
return iobuf;
}
/**
@ -132,9 +145,12 @@ struct io_buffer * xfer_alloc_iob ( struct xfer_interface *xfer, size_t len ) {
* @ret rc Return status code
*/
int xfer_deliver_iob ( struct xfer_interface *xfer, struct io_buffer *iobuf ) {
struct xfer_interface *dest = xfer_dest ( xfer );
struct xfer_interface *dest = xfer_get_dest ( xfer );
int rc;
return dest->op->deliver_iob ( dest, iobuf );
rc = dest->op->deliver_iob ( dest, iobuf );
xfer_put ( dest );
return rc;
}
/**
@ -146,9 +162,12 @@ int xfer_deliver_iob ( struct xfer_interface *xfer, struct io_buffer *iobuf ) {
*/
int xfer_deliver_raw ( struct xfer_interface *xfer,
const void *data, size_t len ) {
struct xfer_interface *dest = xfer_dest ( xfer );
struct xfer_interface *dest = xfer_get_dest ( xfer );
int rc;
return dest->op->deliver_raw ( dest, data, len );
rc = dest->op->deliver_raw ( dest, data, len );
xfer_put ( dest );
return rc;
}
/****************************************************************************

View File

@ -34,7 +34,8 @@ struct interface {
* @v intf Interface
* @ret intf Interface
*/
static inline struct interface * intf_get ( struct interface *intf ) {
static inline __attribute__ (( always_inline )) struct interface *
intf_get ( struct interface *intf ) {
ref_get ( intf->refcnt );
return intf;
}
@ -44,7 +45,8 @@ static inline struct interface * intf_get ( struct interface *intf ) {
*
* @v intf Interface
*/
static inline void intf_put ( struct interface *intf ) {
static inline __attribute__ (( always_inline )) void
intf_put ( struct interface *intf ) {
ref_put ( intf->refcnt );
}

View File

@ -104,14 +104,24 @@ intf_to_job ( struct interface *intf ) {
}
/**
* Get destination job control interface
* Get reference to destination job control interface
*
* @v job Job control interface
* @ret dest Destination interface
*/
static inline __attribute__ (( always_inline )) struct job_interface *
job_dest ( struct job_interface *job ) {
return intf_to_job ( job->intf.dest );
job_get_dest ( struct job_interface *job ) {
return intf_to_job ( intf_get ( job->intf.dest ) );
}
/**
* Drop reference to job control interface
*
* @v job Job control interface
*/
static inline __attribute__ (( always_inline )) void
job_put ( struct job_interface *job ) {
intf_put ( &job->intf );
}
/**

View File

@ -173,14 +173,24 @@ intf_to_xfer ( struct interface *intf ) {
}
/**
* Get destination data transfer interface
* Get reference to destination data transfer interface
*
* @v xfer Data transfer interface
* @ret dest Destination interface
*/
static inline __attribute__ (( always_inline )) struct xfer_interface *
xfer_dest ( struct xfer_interface *xfer ) {
return intf_to_xfer ( xfer->intf.dest );
xfer_get_dest ( struct xfer_interface *xfer ) {
return intf_to_xfer ( intf_get ( xfer->intf.dest ) );
}
/**
* Drop reference to data transfer interface
*
* @v xfer Data transfer interface
*/
static inline __attribute__ (( always_inline )) void
xfer_put ( struct xfer_interface *xfer ) {
intf_put ( &xfer->intf );
}
/**
@ -189,8 +199,8 @@ xfer_dest ( struct xfer_interface *xfer ) {
* @v xfer Data transfer interface
* @v dest New destination interface
*/
static inline void xfer_plug ( struct xfer_interface *xfer,
struct xfer_interface *dest ) {
static inline __attribute__ (( always_inline )) void
xfer_plug ( struct xfer_interface *xfer, struct xfer_interface *dest ) {
plug ( &xfer->intf, &dest->intf );
}
@ -200,8 +210,8 @@ static inline void xfer_plug ( struct xfer_interface *xfer,
* @v a Data transfer interface A
* @v b Data transfer interface B
*/
static inline void xfer_plug_plug ( struct xfer_interface *a,
struct xfer_interface *b ) {
static inline __attribute__ (( always_inline )) void
xfer_plug_plug ( struct xfer_interface *a, struct xfer_interface *b ) {
plug_plug ( &a->intf, &b->intf );
}
@ -210,7 +220,8 @@ static inline void xfer_plug_plug ( struct xfer_interface *a,
*
* @v xfer Data transfer interface
*/
static inline void xfer_unplug ( struct xfer_interface *xfer ) {
static inline __attribute__ (( always_inline )) void
xfer_unplug ( struct xfer_interface *xfer ) {
plug ( &xfer->intf, &null_xfer.intf );
}