[PATCH libX11 v2 1/4] Add _XGetRequest as substitute for GetReq/GetReqExtra

[walter harms]

Am 27.10.2011 06:21, schrieb Peter Hutterer:
> Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
> ---
> Changes to v1:
> - a few comment fixes, whitespace fixes to better align the code with the
>   rest of the file
> - Warning added to _XGetRequest
> - typecast added to _XGetRequest usage from macros
> 
>  include/X11/Xlibint.h |   49 ++++++++++++++++---------------------------------
>  src/XlibInt.c         |   31 +++++++++++++++++++++++++++++++
>  2 files changed, 47 insertions(+), 33 deletions(-)
> 
> diff --git a/include/X11/Xlibint.h b/include/X11/Xlibint.h
> index 2ce356d..43d1f2a 100644
> --- a/include/X11/Xlibint.h
> +++ b/include/X11/Xlibint.h
> @@ -420,6 +420,18 @@ extern LockInfoPtr _Xglobal_lock;
>  #define WORD64ALIGN
>  #endif /* WORD64 */
>  
> +/**
> + * Return a len-sized request buffer for the request type. This function may
> + * flush the output queue.
> + *
> + * @param dpy The display connection
> + * @param type The request type
> + * @param len Length of the request in bytes
> + *
> + * @returns A pointer to the request buffer with a few default values
> + * initialized.
> + */
> +extern void *_XGetRequest(Display *dpy, CARD8 type, size_t len);
>  
>  /*
>   * GetReq - Get the next available X request packet in the buffer and
> @@ -432,25 +444,10 @@ extern LockInfoPtr _Xglobal_lock;
>  
>  #if !defined(UNIXCPP) || defined(ANSICPP)
>  #define GetReq(name, req) \
> -        WORD64ALIGN\
> -	if ((dpy->bufptr + SIZEOF(x##name##Req)) > dpy->bufmax)\
> -		_XFlush(dpy);\
> -	req = (x##name##Req *)(dpy->last_req = dpy->bufptr);\
> -	req->reqType = X_##name;\
> -	req->length = (SIZEOF(x##name##Req))>>2;\
> -	dpy->bufptr += SIZEOF(x##name##Req);\
> -	dpy->request++
> -
> +	req = (x##name##Req *) _XGetRequest(dpy, X_##name, SIZEOF(x##name##Req))
>  #else  /* non-ANSI C uses empty comment instead of "##" for token concatenation */
>  #define GetReq(name, req) \
> -        WORD64ALIGN\
> -	if ((dpy->bufptr + SIZEOF(x/**/name/**/Req)) > dpy->bufmax)\
> -		_XFlush(dpy);\
> -	req = (x/**/name/**/Req *)(dpy->last_req = dpy->bufptr);\
> -	req->reqType = X_/**/name;\
> -	req->length = (SIZEOF(x/**/name/**/Req))>>2;\
> -	dpy->bufptr += SIZEOF(x/**/name/**/Req);\
> -	dpy->request++
> +	req = (x/**/name/**/Req *) _XGetRequest(dpy, X_/**/name, SIZEOF(x/**/name/**/Req))
>  #endif
>  
>  /* GetReqExtra is the same as GetReq, but allocates "n" additional
> @@ -458,24 +455,10 @@ extern LockInfoPtr _Xglobal_lock;
>  
>  #if !defined(UNIXCPP) || defined(ANSICPP)
>  #define GetReqExtra(name, n, req) \
> -        WORD64ALIGN\
> -	if ((dpy->bufptr + SIZEOF(x##name##Req) + n) > dpy->bufmax)\
> -		_XFlush(dpy);\
> -	req = (x##name##Req *)(dpy->last_req = dpy->bufptr);\
> -	req->reqType = X_##name;\
> -	req->length = (SIZEOF(x##name##Req) + n)>>2;\
> -	dpy->bufptr += SIZEOF(x##name##Req) + n;\
> -	dpy->request++
> +	req = (x##name##Req *) _XGetRequest(dpy, X_##name, SIZEOF(x##name##Req) + n)
>  #else
>  #define GetReqExtra(name, n, req) \
> -        WORD64ALIGN\
> -	if ((dpy->bufptr + SIZEOF(x/**/name/**/Req) + n) > dpy->bufmax)\
> -		_XFlush(dpy);\
> -	req = (x/**/name/**/Req *)(dpy->last_req = dpy->bufptr);\
> -	req->reqType = X_/**/name;\
> -	req->length = (SIZEOF(x/**/name/**/Req) + n)>>2;\
> -	dpy->bufptr += SIZEOF(x/**/name/**/Req) + n;\
> -	dpy->request++
> +	req = (x/**/name/**/Req *) _XGetRequest(dpy, X_/**/name, SIZEOF(x/**/name/**/Req) + n)
>  #endif
>  
>  
> diff --git a/src/XlibInt.c b/src/XlibInt.c
> index 3db151e..a8f5d08 100644
> --- a/src/XlibInt.c
> +++ b/src/XlibInt.c
> @@ -1956,6 +1956,37 @@ Screen *_XScreenOfWindow(Display *dpy, Window w)
>  }
>  
>  
> +/*
> + * WARNING: This implementation's pre-conditions and post-conditions
> + * must remain compatible with the old macro-based implementations of
> + * GetReq, GetReqExtra, GetResReq, and GetEmptyReq. The portions of the
> + * Display structure affected by those macros are part of libX11's
> + * ABI.
> + */
> +void *_XGetRequest(Display *dpy, CARD8 type, size_t len)
> +{
> +    xReq *req;
> +
> +    WORD64ALIGN
> +
> +    if (dpy->bufptr + len > dpy->bufmax)
> +	_XFlush(dpy);
> +
> +    if (len % 4)
> +	fprintf(stderr,
> +		"Xlib: request %d length %zd not a multiple of 4.\n",
> +		type, len);

Does it make sense to continue here ?
perhaps you want a add a return NULL ?

re,
 wh

> +
> +    dpy->last_req = dpy->bufptr;
> +
> +    req = (xReq*)dpy->bufptr;
> +    req->reqType = type;
> +    req->length = len / 4;
> +    dpy->bufptr += len;
> +    dpy->request++;
> +    return req;
> +}
> +
>  #if defined(WIN32)
>  
>  /*