Win32: event flags handling edge cases in ngx_wsarecv().

Fixed event flags handling edge cases in ngx_wsarecv() and ngx_wsarecv_chain(),
notably to always reset rev->ready in case of errors (which wasn't the case
after ngx_socket_nread() errors), and after EOF (rev->ready was not cleared
if due to a misconfiguration a zero-sized buffer was used for reading).

src/os/win32/ngx_wsarecv.c

@@ -78,6 +78,7 @@ ngx_wsarecv(ngx_connection_t *c, u_char *buf, size_t size)
                                      ngx_socket_nread_n " failed");
 
             if (n == NGX_ERROR) {
+                rev->ready = 0;
                 rev->error = 1;
             }
 
@@ -95,6 +96,7 @@ ngx_wsarecv(ngx_connection_t *c, u_char *buf, size_t size)
     }
 
     if (bytes == 0) {
+        rev->ready = 0;
         rev->eof = 1;
     }
 

src/os/win32/ngx_wsarecv_chain.c

@@ -121,6 +121,7 @@ ngx_wsarecv_chain(ngx_connection_t *c, ngx_chain_t *chain, off_t limit)
     } else if (bytes == size) {
 
         if (ngx_socket_nread(c->fd, &rev->available) == -1) {
+            rev->ready = 0;
             rev->error = 1;
             ngx_connection_error(c, ngx_socket_errno,
                                  ngx_socket_nread_n " failed");
@@ -138,6 +139,7 @@ ngx_wsarecv_chain(ngx_connection_t *c, ngx_chain_t *chain, off_t limit)
     }
 
     if (bytes == 0) {
+        rev->ready = 0;
         rev->eof = 1;
     }