src/http/ngx_http_spdy_filter_module.c, latest changesets compiler warnings

[Valentin V. Bartenev]

On Tuesday 14 January 2014 17:36:23 itpp2012 wrote:
> You missed 2,
> 
> Line +-683:
>             if (offset) {
>                 cl = ngx_http_spdy_filter_get_shadow(stream, in->buf,
> //                                                     offset, size);
>                                                      (off_t) offset,
> (size_t) size);
>                 if (cl == NULL) {
>                     return NGX_CHAIN_ERROR;
>                 }
> 
> and +-Line 760:
>     if (offset) {
> //        cl = ngx_http_spdy_filter_get_shadow(stream, in->buf, offset,
> size);
>         cl = ngx_http_spdy_filter_get_shadow(stream, in->buf, (off_t)
> offset, (size_t) size);
>         if (cl == NULL) {
>             return NGX_CHAIN_ERROR;
>         }
> 
> 
> Additional warning +-line 684:
>             if (offset) {
>                 cl = ngx_http_spdy_filter_get_shadow(stream, in->buf,
>                                                     (off_t) offset, (size_t)
> size);
>                 if (cl == NULL) {
>                     return NGX_CHAIN_ERROR;
>                 }
> 
>                 offset = 0;
> 
> src\http\ngx_http_spdy_filter_module.c(685): warning C4701: potentially
> uninitialized local variable 'cl' used
> 
> When I add +-line 629:
>     ngx_http_spdy_stream_t     *stream;
>     ngx_http_spdy_loc_conf_t   *slcf;
>     ngx_http_spdy_out_frame_t  *frame;
> +    cl = NULL;
> 
> The warning is gone.
> 
[..]

Thanks!  I've just checked these two patches on MSVC 2010,
and it seems all warnings are gone:

# HG changeset patch
# User Valentin Bartenev <vbart at nginx.com>
# Date 1389735892 -14400
# Node ID 439d05a037a344ae8d38b162a98391f92321d03b
# Parent  e5fb14e850408b2250f81751b69d2f735bbe8edc
SPDY: fixed build, broken by b7ee1bae0ffa.

False positive warning about the "cl" variable may be uninitialized in
the ngx_http_spdy_filter_get_data_frame() call was suppressed.

It is always initialized either in the "while" cycle or in the following
"if" condition since frame_size cannot be zero.

diff -r e5fb14e85040 -r 439d05a037a3 src/http/ngx_http_spdy_filter_module.c
--- a/src/http/ngx_http_spdy_filter_module.c    Tue Jan 14 16:24:45 2014 +0400
+++ b/src/http/ngx_http_spdy_filter_module.c    Wed Jan 15 01:44:52 2014 +0400
@@ -665,6 +665,10 @@ ngx_http_spdy_send_chain(ngx_connection_
         offset = 0;
     }
 
+#if (NGX_SUPPRESS_WARN)
+    cl = NULL;
+#endif
+
     slcf = ngx_http_get_module_loc_conf(r, ngx_http_spdy_module);
 
     frame_size = (limit && limit <= (off_t) slcf->chunk_size)
# HG changeset patch
# User Valentin Bartenev <vbart at nginx.com>
# Date 1389740560 -14400
# Node ID 3d83b3f1354d7d56f1e31849bfa337f75d7b1d30
# Parent  439d05a037a344ae8d38b162a98391f92321d03b
SPDY: fixed off_t/size_t type conversions on 32 bits platforms.

diff -r 439d05a037a3 -r 3d83b3f1354d src/http/ngx_http_spdy_filter_module.c
--- a/src/http/ngx_http_spdy_filter_module.c    Wed Jan 15 01:44:52 2014 +0400
+++ b/src/http/ngx_http_spdy_filter_module.c    Wed Jan 15 03:02:40 2014 +0400
@@ -35,8 +35,7 @@ static ngx_inline ngx_int_t ngx_http_spd
     ngx_connection_t *fc, ngx_http_spdy_stream_t *stream);
 
 static ngx_chain_t *ngx_http_spdy_filter_get_shadow(
-    ngx_http_spdy_stream_t *stream, ngx_buf_t *buf, size_t offset,
-    size_t size);
+    ngx_http_spdy_stream_t *stream, ngx_buf_t *buf, off_t offset, off_t size);
 static ngx_http_spdy_out_frame_t *ngx_http_spdy_filter_get_data_frame(
     ngx_http_spdy_stream_t *stream, size_t len, ngx_chain_t *first,
     ngx_chain_t *last);
@@ -702,7 +701,7 @@ ngx_http_spdy_send_chain(ngx_connection_
             *ln = cl;
             ln = &cl->next;
 
-            rest -= size;
+            rest -= (size_t) size;
             in = in->next;
 
             if (in == NULL) {
@@ -752,7 +751,7 @@ ngx_http_spdy_send_chain(ngx_connection_
             }
 
             if (limit < (off_t) slcf->chunk_size) {
-                frame_size = limit;
+                frame_size = (size_t) limit;
             }
         }
     }
@@ -777,7 +776,7 @@ ngx_http_spdy_send_chain(ngx_connection_
 
 static ngx_chain_t *
 ngx_http_spdy_filter_get_shadow(ngx_http_spdy_stream_t *stream, ngx_buf_t *buf,
-    size_t offset, size_t size)
+    off_t offset, off_t size)
 {
     ngx_buf_t    *chunk;
     ngx_chain_t  *cl;