Mercurial > hg > nginx-quic
view src/core/ngx_crc32.h @ 4385:70ba81827472
Cache locks initial implementation.
New directives: proxy_cache_lock on/off, proxy_cache_lock_timeout. With
proxy_cache_lock set to on, only one request will be allowed to go to
upstream for a particular cache item. Others will wait for a response
to appear in cache (or cache lock released) up to proxy_cache_lock_timeout.
Waiting requests will recheck if they have cached response ready (or are
allowed to run) every 500ms.
Note: we intentionally don't intercept NGX_DECLINED possibly returned by
ngx_http_file_cache_read(). This needs more work (possibly safe, but needs
further investigation). Anyway, it's exceptional situation.
Note: probably there should be a way to disable caching of responses
if there is already one request fetching resource to cache (without waiting
at all). Two possible ways include another cache lock option ("no_cache")
or using proxy_no_cache with some supplied variable.
Note: probably there should be a way to lock updating requests as well. For
now "proxy_cache_use_stale updating" is available.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 26 Dec 2011 11:15:23 +0000 |
parents | d6afb8723155 |
children | d620f497c50f |
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/* * Copyright (C) Igor Sysoev */ #ifndef _NGX_CRC32_H_INCLUDED_ #define _NGX_CRC32_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> extern uint32_t *ngx_crc32_table_short; extern uint32_t ngx_crc32_table256[]; static ngx_inline uint32_t ngx_crc32_short(u_char *p, size_t len) { u_char c; uint32_t crc; crc = 0xffffffff; while (len--) { c = *p++; crc = ngx_crc32_table_short[(crc ^ (c & 0xf)) & 0xf] ^ (crc >> 4); crc = ngx_crc32_table_short[(crc ^ (c >> 4)) & 0xf] ^ (crc >> 4); } return crc ^ 0xffffffff; } static ngx_inline uint32_t ngx_crc32_long(u_char *p, size_t len) { uint32_t crc; crc = 0xffffffff; while (len--) { crc = ngx_crc32_table256[(crc ^ *p++) & 0xff] ^ (crc >> 8); } return crc ^ 0xffffffff; } #define ngx_crc32_init(crc) \ crc = 0xffffffff static ngx_inline void ngx_crc32_update(uint32_t *crc, u_char *p, size_t len) { uint32_t c; c = *crc; while (len--) { c = ngx_crc32_table256[(c ^ *p++) & 0xff] ^ (c >> 8); } *crc = c; } #define ngx_crc32_final(crc) \ crc ^= 0xffffffff ngx_int_t ngx_crc32_table_init(void); #endif /* _NGX_CRC32_H_INCLUDED_ */