Merge of r4985, r4986, r4987, r4988, r4989, r5002: access_log gzip. *) Access log: fixed redundant buffer reallocation. Previously a new buffer was allocated for every "access_log" directive with the same file path and "buffer=" parameters, while only one buffer per file is used. *) Reopening log files code moved to a separate function. The code refactored in a way to call custom handler that can do appropriate cleanup work (if any), like flushing buffers, finishing compress streams, finalizing connections to log daemon, etc.. *) Access log: the "flush" parameter of the "access_log" directive. *) Configure: added the NGX_ZLIB define. This was introduced for conditional compilation of the code that requires the zlib library. *) Access log: the "gzip" parameter of the "access_log" directive. Note: this requires zlib version 1.2.0.4 or above to work. *) The data pointer in ngx_open_file_t objects must be initialized. Uninitialized pointer may result in arbitrary segfaults if access_log is used without buffer and without variables in file path. Patch by Tatsuhiko Kubo (ticket #268).

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


#ifndef _NGX_SLAB_H_INCLUDED_
#define _NGX_SLAB_H_INCLUDED_


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


typedef struct ngx_slab_page_s  ngx_slab_page_t;

struct ngx_slab_page_s {
    uintptr_t         slab;
    ngx_slab_page_t  *next;
    uintptr_t         prev;
};


typedef struct {
    ngx_shmtx_sh_t    lock;

    size_t            min_size;
    size_t            min_shift;

    ngx_slab_page_t  *pages;
    ngx_slab_page_t   free;

    u_char           *start;
    u_char           *end;

    ngx_shmtx_t       mutex;

    u_char           *log_ctx;
    u_char            zero;

    void             *data;
    void             *addr;
} ngx_slab_pool_t;


void ngx_slab_init(ngx_slab_pool_t *pool);
void *ngx_slab_alloc(ngx_slab_pool_t *pool, size_t size);
void *ngx_slab_alloc_locked(ngx_slab_pool_t *pool, size_t size);
void ngx_slab_free(ngx_slab_pool_t *pool, void *p);
void ngx_slab_free_locked(ngx_slab_pool_t *pool, void *p);


#endif /* _NGX_SLAB_H_INCLUDED_ */