Event pipe: do not set file's thread_handler if not needed. This fixes a problem with aio threads and sendfile with aio_write switched off, as observed with range requests after fc72784b1f52 (1.9.13). Potential problems with sendfile in threads were previously described in 9fd738b85fad, and this seems to be one of them. The problem occurred as file's thread_handler was set to NULL by event pipe code after a sendfile thread task was scheduled. As a result, no sendfile completion code was executed, and the same buffer was additionally sent using non-threaded sendfile. Fix is to avoid modifying file's thread_handler if aio_write is switched off. Note that with "aio_write on" it is still possible that sendfile will use thread_handler as set by event pipe. This is believed to be safe though, as handlers used are compatible.

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


#ifndef _NGX_DARWIN_H_INCLUDED_
#define _NGX_DARWIN_H_INCLUDED_


void ngx_debug_init(void);
ngx_chain_t *ngx_darwin_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in,
    off_t limit);

extern int       ngx_darwin_kern_osreldate;
extern int       ngx_darwin_hw_ncpu;
extern u_long    ngx_darwin_net_inet_tcp_sendspace;

extern ngx_uint_t  ngx_debug_malloc;


#endif /* _NGX_DARWIN_H_INCLUDED_ */