From de636d491bad83a6e67d404928a6c82b628300cf Mon Sep 17 00:00:00 2001
From: "Enrico Weigelt, metux IT consult" <info@metux.net>
Date: Thu, 4 Jul 2024 20:24:15 +0200
Subject: [PATCH] Xext: vidmode: tidy up multi-version request control flow,
 part 3

Some requests using different structs dependending on which protocol version
(v1 vs. v2) had been selected. That's is handled by coverting v1 structs into v2,
before proceeding with the actual handling.

The code flow of this is very complex and hard to understand. Cleaning this up
in several smaller steps, that are easier to digest.

This part moves the request payload structs (or pointers to them) into the
per-version branches. Within each branch following our usual scheme for
extension request handlers (eg. using the REQUEST*() macros and having a
pointer named `stuff` to the current request struct)

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
---
 Xext/vidmode.c | 281 ++++++++++++++++++++++---------------------------
 1 file changed, 127 insertions(+), 154 deletions(-)

diff --git a/Xext/vidmode.c b/Xext/vidmode.c
index 89036e34c..77d29a8b6 100644
--- a/Xext/vidmode.c
+++ b/Xext/vidmode.c
@@ -438,12 +438,7 @@ static int VidModeAddModeLine(ClientPtr client, xXF86VidModeAddModeLineReq* stuf
 static int
 ProcVidModeAddModeLine(ClientPtr client)
 {
-    REQUEST(xXF86VidModeAddModeLineReq);
-    xXF86OldVidModeAddModeLineReq *oldstuff =
-        (xXF86OldVidModeAddModeLineReq *) client->requestBuffer;
-    xXF86VidModeAddModeLineReq newstuff;
     int len;
-    int ver;
 
     /* limited to local-only connections */
     if (!VidModeAllowNonLocal && !client->local)
@@ -451,55 +446,54 @@ ProcVidModeAddModeLine(ClientPtr client)
 
     DEBUG_P("XF86VidModeAddModeline");
 
-    ver = ClientMajorVersion(client);
-
-    if (ver < 2) {
+    if (ClientMajorVersion(client) < 2) {
+        REQUEST(xXF86OldVidModeAddModeLineReq);
         REQUEST_AT_LEAST_SIZE(xXF86OldVidModeAddModeLineReq);
         len =
             client->req_len -
             bytes_to_int32(sizeof(xXF86OldVidModeAddModeLineReq));
-        if (len != oldstuff->privsize)
+        if (len != stuff->privsize)
             return BadLength;
+
+        xXF86VidModeAddModeLineReq newstuff = {
+            .length = client->req_len,
+            .screen = stuff->screen,
+            .dotclock = stuff->dotclock,
+            .hdisplay = stuff->hdisplay,
+            .hsyncstart = stuff->hsyncstart,
+            .hsyncend = stuff->hsyncend,
+            .htotal = stuff->htotal,
+            .hskew = 0,
+            .vdisplay = stuff->vdisplay,
+            .vsyncstart = stuff->vsyncstart,
+            .vsyncend = stuff->vsyncend,
+            .vtotal = stuff->vtotal,
+            .flags = stuff->flags,
+            .privsize = stuff->privsize,
+            .after_dotclock = stuff->after_dotclock,
+            .after_hdisplay = stuff->after_hdisplay,
+            .after_hsyncstart = stuff->after_hsyncstart,
+            .after_hsyncend = stuff->after_hsyncend,
+            .after_htotal = stuff->after_htotal,
+            .after_hskew = 0,
+            .after_vdisplay = stuff->after_vdisplay,
+            .after_vsyncstart = stuff->after_vsyncstart,
+            .after_vsyncend = stuff->after_vsyncend,
+            .after_vtotal = stuff->after_vtotal,
+            .after_flags = stuff->after_flags,
+        };
+        return VidModeAddModeLine(client, &newstuff);
     }
     else {
+        REQUEST(xXF86VidModeAddModeLineReq);
         REQUEST_AT_LEAST_SIZE(xXF86VidModeAddModeLineReq);
         len =
             client->req_len -
             bytes_to_int32(sizeof(xXF86VidModeAddModeLineReq));
         if (len != stuff->privsize)
             return BadLength;
+        return VidModeAddModeLine(client, stuff);
     }
-
-    if (ver < 2) {
-        /* convert from old format */
-        stuff = &newstuff;
-        stuff->length = client->req_len;
-        stuff->screen = oldstuff->screen;
-        stuff->dotclock = oldstuff->dotclock;
-        stuff->hdisplay = oldstuff->hdisplay;
-        stuff->hsyncstart = oldstuff->hsyncstart;
-        stuff->hsyncend = oldstuff->hsyncend;
-        stuff->htotal = oldstuff->htotal;
-        stuff->hskew = 0;
-        stuff->vdisplay = oldstuff->vdisplay;
-        stuff->vsyncstart = oldstuff->vsyncstart;
-        stuff->vsyncend = oldstuff->vsyncend;
-        stuff->vtotal = oldstuff->vtotal;
-        stuff->flags = oldstuff->flags;
-        stuff->privsize = oldstuff->privsize;
-        stuff->after_dotclock = oldstuff->after_dotclock;
-        stuff->after_hdisplay = oldstuff->after_hdisplay;
-        stuff->after_hsyncstart = oldstuff->after_hsyncstart;
-        stuff->after_hsyncend = oldstuff->after_hsyncend;
-        stuff->after_htotal = oldstuff->after_htotal;
-        stuff->after_hskew = 0;
-        stuff->after_vdisplay = oldstuff->after_vdisplay;
-        stuff->after_vsyncstart = oldstuff->after_vsyncstart;
-        stuff->after_vsyncend = oldstuff->after_vsyncend;
-        stuff->after_vtotal = oldstuff->after_vtotal;
-        stuff->after_flags = oldstuff->after_flags;
-    }
-    return VidModeAddModeLine(client, stuff);
 }
 
 static int VidModeAddModeLine(ClientPtr client, xXF86VidModeAddModeLineReq* stuff)
@@ -623,12 +617,7 @@ VidModeDeleteModeLine(ClientPtr client, xXF86VidModeDeleteModeLineReq* stuff);
 static int
 ProcVidModeDeleteModeLine(ClientPtr client)
 {
-    REQUEST(xXF86VidModeDeleteModeLineReq);
-    xXF86OldVidModeDeleteModeLineReq *oldstuff =
-        (xXF86OldVidModeDeleteModeLineReq *) client->requestBuffer;
-    xXF86VidModeDeleteModeLineReq newstuff;
     int len;
-    int ver;
 
     /* limited to local-only connections */
     if (!VidModeAllowNonLocal && !client->local)
@@ -636,14 +625,13 @@ ProcVidModeDeleteModeLine(ClientPtr client)
 
     DEBUG_P("XF86VidModeDeleteModeline");
 
-    ver = ClientMajorVersion(client);
-
-    if (ver < 2) {
+    if (ClientMajorVersion(client) < 2) {
+        REQUEST(xXF86OldVidModeDeleteModeLineReq);
         REQUEST_AT_LEAST_SIZE(xXF86OldVidModeDeleteModeLineReq);
         len =
             client->req_len -
             bytes_to_int32(sizeof(xXF86OldVidModeDeleteModeLineReq));
-        if (len != oldstuff->privsize) {
+        if (len != stuff->privsize) {
             DebugF("req_len = %ld, sizeof(Req) = %d, privsize = %ld, "
                    "len = %d, length = %d\n",
                    (unsigned long) client->req_len,
@@ -651,8 +639,28 @@ ProcVidModeDeleteModeLine(ClientPtr client)
                    (unsigned long) stuff->privsize, len, client->req_len);
             return BadLength;
         }
+
+        /* convert from old format */
+        xXF86VidModeDeleteModeLineReq newstuff = {
+            .length = client->req_len,
+            .screen = stuff->screen,
+            .dotclock = stuff->dotclock,
+            .hdisplay = stuff->hdisplay,
+            .hsyncstart = stuff->hsyncstart,
+            .hsyncend = stuff->hsyncend,
+            .htotal = stuff->htotal,
+            .hskew = 0,
+            .vdisplay = stuff->vdisplay,
+            .vsyncstart = stuff->vsyncstart,
+            .vsyncend = stuff->vsyncend,
+            .vtotal = stuff->vtotal,
+            .flags = stuff->flags,
+            .privsize = stuff->privsize,
+        };
+        return VidModeDeleteModeLine(client, &newstuff);
     }
     else {
+        REQUEST(xXF86VidModeDeleteModeLineReq);
         REQUEST_AT_LEAST_SIZE(xXF86VidModeDeleteModeLineReq);
         len =
             client->req_len -
@@ -665,27 +673,8 @@ ProcVidModeDeleteModeLine(ClientPtr client)
                    (unsigned long) stuff->privsize, len, client->req_len);
             return BadLength;
         }
+        return VidModeDeleteModeLine(client, stuff);
     }
-
-    if (ver < 2) {
-        /* convert from old format */
-        stuff = &newstuff;
-        stuff->length = client->req_len;
-        stuff->screen = oldstuff->screen;
-        stuff->dotclock = oldstuff->dotclock;
-        stuff->hdisplay = oldstuff->hdisplay;
-        stuff->hsyncstart = oldstuff->hsyncstart;
-        stuff->hsyncend = oldstuff->hsyncend;
-        stuff->htotal = oldstuff->htotal;
-        stuff->hskew = 0;
-        stuff->vdisplay = oldstuff->vdisplay;
-        stuff->vsyncstart = oldstuff->vsyncstart;
-        stuff->vsyncend = oldstuff->vsyncend;
-        stuff->vtotal = oldstuff->vtotal;
-        stuff->flags = oldstuff->flags;
-        stuff->privsize = oldstuff->privsize;
-    }
-    return VidModeDeleteModeLine(client, stuff);
 }
 
 static int
@@ -769,12 +758,7 @@ VidModeModModeLine(ClientPtr client, xXF86VidModeModModeLineReq *stuff);
 static int
 ProcVidModeModModeLine(ClientPtr client)
 {
-    REQUEST(xXF86VidModeModModeLineReq);
-    xXF86OldVidModeModModeLineReq *oldstuff =
-        (xXF86OldVidModeModModeLineReq *) client->requestBuffer;
-    xXF86VidModeModModeLineReq newstuff;
     int len;
-    int ver;
 
     /* limited to local-only connections */
     if (!VidModeAllowNonLocal && !client->local)
@@ -782,43 +766,43 @@ ProcVidModeModModeLine(ClientPtr client)
 
     DEBUG_P("XF86VidModeModModeline");
 
-    ver = ClientMajorVersion(client);
-
-    if (ver < 2) {
+    if (ClientMajorVersion(client) < 2) {
+        REQUEST(xXF86OldVidModeModModeLineReq)
         REQUEST_AT_LEAST_SIZE(xXF86OldVidModeModModeLineReq);
         len =
             client->req_len -
             bytes_to_int32(sizeof(xXF86OldVidModeModModeLineReq));
-        if (len != oldstuff->privsize)
+        if (len != stuff->privsize)
             return BadLength;
+
+        /* convert from old format */
+        xXF86VidModeModModeLineReq newstuff = {
+            .length = client->req_len,
+            .screen = stuff->screen,
+            .hdisplay = stuff->hdisplay,
+            .hsyncstart = stuff->hsyncstart,
+            .hsyncend = stuff->hsyncend,
+            .htotal = stuff->htotal,
+            .hskew = 0,
+            .vdisplay = stuff->vdisplay,
+            .vsyncstart = stuff->vsyncstart,
+            .vsyncend = stuff->vsyncend,
+            .vtotal = stuff->vtotal,
+            .flags = stuff->flags,
+            .privsize = stuff->privsize,
+        };
+        return VidModeModModeLine(client, &newstuff);
     }
     else {
+        REQUEST(xXF86VidModeModModeLineReq);
         REQUEST_AT_LEAST_SIZE(xXF86VidModeModModeLineReq);
         len =
             client->req_len -
             bytes_to_int32(sizeof(xXF86VidModeModModeLineReq));
         if (len != stuff->privsize)
             return BadLength;
+        return VidModeModModeLine(client, stuff);
     }
-
-    if (ver < 2) {
-        /* convert from old format */
-        stuff = &newstuff;
-        stuff->length = client->req_len;
-        stuff->screen = oldstuff->screen;
-        stuff->hdisplay = oldstuff->hdisplay;
-        stuff->hsyncstart = oldstuff->hsyncstart;
-        stuff->hsyncend = oldstuff->hsyncend;
-        stuff->htotal = oldstuff->htotal;
-        stuff->hskew = 0;
-        stuff->vdisplay = oldstuff->vdisplay;
-        stuff->vsyncstart = oldstuff->vsyncstart;
-        stuff->vsyncend = oldstuff->vsyncend;
-        stuff->vtotal = oldstuff->vtotal;
-        stuff->flags = oldstuff->flags;
-        stuff->privsize = oldstuff->privsize;
-    }
-    return VidModeModModeLine(client, stuff);
 }
 
 static int
@@ -922,52 +906,46 @@ VidModeValidateModeLine(ClientPtr client, xXF86VidModeValidateModeLineReq *stuff
 static int
 ProcVidModeValidateModeLine(ClientPtr client)
 {
-    REQUEST(xXF86VidModeValidateModeLineReq);
-    xXF86OldVidModeValidateModeLineReq *oldstuff =
-        (xXF86OldVidModeValidateModeLineReq *) client->requestBuffer;
-    xXF86VidModeValidateModeLineReq newstuff;
     int len;
-    int ver;
 
     DEBUG_P("XF86VidModeValidateModeline");
 
-    ver = ClientMajorVersion(client);
-
-    if (ver < 2) {
+    if (ClientMajorVersion(client) < 2) {
+        REQUEST(xXF86OldVidModeValidateModeLineReq);
         REQUEST_AT_LEAST_SIZE(xXF86OldVidModeValidateModeLineReq);
         len = client->req_len -
             bytes_to_int32(sizeof(xXF86OldVidModeValidateModeLineReq));
-        if (len != oldstuff->privsize)
+        if (len != stuff->privsize)
             return BadLength;
+
+        xXF86VidModeValidateModeLineReq newstuff = {
+            .length = client->req_len,
+            .screen = stuff->screen,
+            .dotclock = stuff->dotclock,
+            .hdisplay = stuff->hdisplay,
+            .hsyncstart = stuff->hsyncstart,
+            .hsyncend = stuff->hsyncend,
+            .htotal = stuff->htotal,
+            .hskew = 0,
+            .vdisplay = stuff->vdisplay,
+            .vsyncstart = stuff->vsyncstart,
+            .vsyncend = stuff->vsyncend,
+            .vtotal = stuff->vtotal,
+            .flags = stuff->flags,
+            .privsize = stuff->privsize,
+        };
+        return VidModeValidateModeLine(client, &newstuff);
     }
     else {
+        REQUEST(xXF86VidModeValidateModeLineReq);
         REQUEST_AT_LEAST_SIZE(xXF86VidModeValidateModeLineReq);
         len =
             client->req_len -
             bytes_to_int32(sizeof(xXF86VidModeValidateModeLineReq));
         if (len != stuff->privsize)
             return BadLength;
+        return VidModeValidateModeLine(client, stuff);
     }
-
-    if (ver < 2) {
-        /* convert from old format */
-        stuff = &newstuff;
-        stuff->length = client->req_len;
-        stuff->screen = oldstuff->screen;
-        stuff->dotclock = oldstuff->dotclock;
-        stuff->hdisplay = oldstuff->hdisplay;
-        stuff->hsyncstart = oldstuff->hsyncstart;
-        stuff->hsyncend = oldstuff->hsyncend;
-        stuff->htotal = oldstuff->htotal;
-        stuff->hskew = 0;
-        stuff->vdisplay = oldstuff->vdisplay;
-        stuff->vsyncstart = oldstuff->vsyncstart;
-        stuff->vsyncend = oldstuff->vsyncend;
-        stuff->vtotal = oldstuff->vtotal;
-        stuff->flags = oldstuff->flags;
-        stuff->privsize = oldstuff->privsize;
-    }
-    return VidModeValidateModeLine(client, stuff);
 }
 
 static int
@@ -1093,12 +1071,7 @@ VidModeSwitchToMode(ClientPtr client, xXF86VidModeSwitchToModeReq *stuff);
 static int
 ProcVidModeSwitchToMode(ClientPtr client)
 {
-    REQUEST(xXF86VidModeSwitchToModeReq);
-    xXF86OldVidModeSwitchToModeReq *oldstuff =
-        (xXF86OldVidModeSwitchToModeReq *) client->requestBuffer;
-    xXF86VidModeSwitchToModeReq newstuff;
     int len;
-    int ver;
 
     DEBUG_P("XF86VidModeSwitchToMode");
 
@@ -1106,44 +1079,44 @@ ProcVidModeSwitchToMode(ClientPtr client)
     if (!VidModeAllowNonLocal && !client->local)
         return VidModeErrorBase + XF86VidModeClientNotLocal;
 
-    ver = ClientMajorVersion(client);
-
-    if (ver < 2) {
+    if (ClientMajorVersion(client) < 2) {
+        REQUEST(xXF86OldVidModeSwitchToModeReq);
         REQUEST_AT_LEAST_SIZE(xXF86OldVidModeSwitchToModeReq);
         len =
             client->req_len -
             bytes_to_int32(sizeof(xXF86OldVidModeSwitchToModeReq));
         if (len != stuff->privsize)
             return BadLength;
+
+        /* convert from old format */
+        xXF86VidModeSwitchToModeReq newstuff = {
+            .length = client->req_len,
+            .screen = stuff->screen,
+            .dotclock = stuff->dotclock,
+            .hdisplay = stuff->hdisplay,
+            .hsyncstart = stuff->hsyncstart,
+            .hsyncend = stuff->hsyncend,
+            .htotal = stuff->htotal,
+            .hskew = 0,
+            .vdisplay = stuff->vdisplay,
+            .vsyncstart = stuff->vsyncstart,
+            .vsyncend = stuff->vsyncend,
+            .vtotal = stuff->vtotal,
+            .flags = stuff->flags,
+            .privsize = stuff->privsize,
+        };
+        return VidModeSwitchToMode(client, &newstuff);
     }
     else {
+        REQUEST(xXF86VidModeSwitchToModeReq);
         REQUEST_AT_LEAST_SIZE(xXF86VidModeSwitchToModeReq);
         len =
             client->req_len -
             bytes_to_int32(sizeof(xXF86VidModeSwitchToModeReq));
         if (len != stuff->privsize)
             return BadLength;
+        return VidModeSwitchToMode(client, stuff);
     }
-
-    if (ver < 2) {
-        /* convert from old format */
-        stuff = &newstuff;
-        stuff->length = client->req_len;
-        stuff->screen = oldstuff->screen;
-        stuff->dotclock = oldstuff->dotclock;
-        stuff->hdisplay = oldstuff->hdisplay;
-        stuff->hsyncstart = oldstuff->hsyncstart;
-        stuff->hsyncend = oldstuff->hsyncend;
-        stuff->htotal = oldstuff->htotal;
-        stuff->hskew = 0;
-        stuff->vdisplay = oldstuff->vdisplay;
-        stuff->vsyncstart = oldstuff->vsyncstart;
-        stuff->vsyncend = oldstuff->vsyncend;
-        stuff->vtotal = oldstuff->vtotal;
-        stuff->flags = oldstuff->flags;
-        stuff->privsize = oldstuff->privsize;
-    }
-    return VidModeSwitchToMode(client, stuff);
 }
 
 static int