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) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


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


ngx_err_t
ngx_create_thread(ngx_tid_t *tid,
    ngx_thread_value_t (__stdcall *func)(void *arg), void *arg, ngx_log_t *log)
{
    u_long     id;
    ngx_err_t  err;

    *tid = CreateThread(NULL, 0, func, arg, 0, &id);

    if (*tid != NULL) {
        ngx_log_error(NGX_LOG_NOTICE, log, 0,
                      "create thread " NGX_TID_T_FMT, id);
        return 0;
    }

    err = ngx_errno;
    ngx_log_error(NGX_LOG_ALERT, log, err, "CreateThread() failed");
    return err;
}