Upstream: fixed X-Accel-Expires/Cache-Control/Expires handling. Previously, if caching was disabled due to Expires in the past, nginx failed to cache the response even if it was cacheable as per subsequently parsed Cache-Control header (ticket #964). Similarly, if caching was disabled due to Expires in the past, "Cache-Control: no-cache" or "Cache-Control: max-age=0", caching was not used if it was cacheable as per subsequently parsed X-Accel-Expires header. Fix is to avoid disabling caching immediately after parsing Expires in the past or Cache-Control, but rather set flags which are later checked by ngx_http_upstream_process_headers() (and cleared by "Cache-Control: max-age" and X-Accel-Expires). Additionally, now X-Accel-Expires does not prevent parsing of cache control extensions, notably stale-while-revalidate and stale-if-error. This ensures that order of the X-Accel-Expires and Cache-Control headers is not important. Prodded by Vadim Fedorenko and Yugo Horie.

/*
 * Copyright (C) Maxim Dounin
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_DLOPEN_H_INCLUDED_
#define _NGX_DLOPEN_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>


#define NGX_HAVE_DLOPEN  1


#define ngx_dlopen(path)           LoadLibrary((char *) path)
#define ngx_dlopen_n               "LoadLibrary()"

#define ngx_dlsym(handle, symbol)  (void *) GetProcAddress(handle, symbol)
#define ngx_dlsym_n                "GetProcAddress()"

#define ngx_dlclose(handle)        (FreeLibrary(handle) ? 0 : -1)
#define ngx_dlclose_n              "FreeLibrary()"


char *ngx_dlerror(void);


#endif /* _NGX_DLOPEN_H_INCLUDED_ */