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

[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);
+
+    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)
 
 /*
-- 
1.7.7