/* Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You under the Apache License, Version 2.0

 * (the "License"); you may not use this file except in compliance with

 * the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#include "httpd.h"

#include "http_log.h"

#include "http_request.h"

#include "http_config.h"

#include "http_protocol.h"

#include "mod_status.h"

#include "apr_strings.h"

#include "apr_time.h"

#include "ap_socache.h"

#include "distcache/dc_client.h"

#if !defined(DISTCACHE_CLIENT_API) || (DISTCACHE_CLIENT_API < 0x0001)

#error "You must compile with a more recent version of the distcache-base package"

#endif

struct ap_socache_instance_t {

    /* Configured target server: */

    const char *target;

    /* distcache client context: */

    DC_CTX *dc;

};

static const char *socache_dc_create(ap_socache_instance_t **context,

                                     const char *arg,

                                     apr_pool_t *tmp, apr_pool_t *p)

{

    struct ap_socache_instance_t *ctx;

    ctx = *context = apr_palloc(p, sizeof *ctx);

    ctx->target = apr_pstrdup(p, arg);

    return NULL;

}

static apr_status_t socache_dc_init(ap_socache_instance_t *ctx,

                                    const char *namespace,

                                    const struct ap_socache_hints *hints,

                                    server_rec *s, apr_pool_t *p)

{

#if 0

    /* If a "persistent connection" mode of operation is preferred, you *must*

     * also use the PIDCHECK flag to ensure fork()'d processes don't interlace

     * comms on the same connection as each other. */

#define SESSION_CTX_FLAGS        SESSION_CTX_FLAG_PERSISTENT | \

                                 SESSION_CTX_FLAG_PERSISTENT_PIDCHECK | \

                                 SESSION_CTX_FLAG_PERSISTENT_RETRY | \

                                 SESSION_CTX_FLAG_PERSISTENT_LATE

#else

    /* This mode of operation will open a temporary connection to the 'target'

     * for each cache operation - this makes it safe against fork()

     * automatically. This mode is preferred when running a local proxy (over

     * unix domain sockets) because overhead is negligable and it reduces the

     * performance/stability danger of file-descriptor bloatage. */

#define SESSION_CTX_FLAGS        0

#endif

    ctx->dc = DC_CTX_new(ctx->target, SESSION_CTX_FLAGS);

    if (!ctx->dc) {

        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(00738) "distributed scache failed to obtain context");

        return APR_EGENERAL;

    }

    ap_log_error(APLOG_MARK, APLOG_INFO, 0, s, APLOGNO(00739) "distributed scache context initialised");

    return APR_SUCCESS;

}

static void socache_dc_destroy(ap_socache_instance_t *ctx, server_rec *s)

{

    if (ctx && ctx->dc) {

        DC_CTX_free(ctx->dc);

        ctx->dc = NULL;

    }

}

static apr_status_t socache_dc_store(ap_socache_instance_t *ctx, server_rec *s,

                                     const unsigned char *id, unsigned int idlen,

                                     apr_time_t expiry,

                                     unsigned char *der, unsigned int der_len,

                                     apr_pool_t *p)

{

    /* !@#$%^ - why do we deal with *absolute* time anyway???

     * Uhm - because most things expire things at a specific time?

     * Were the API were thought out expiry - r->request_time is a good approximation

     */

    expiry -= apr_time_now();

    /* Send the serialised session to the distributed cache context */

    if (!DC_CTX_add_session(ctx->dc, id, idlen, der, der_len,

                            apr_time_msec(expiry))) {

        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(00740) "distributed scache 'store' failed");

        return APR_EGENERAL;

    }

    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00741) "distributed scache 'store' successful");

    return APR_SUCCESS;

}

static apr_status_t socache_dc_retrieve(ap_socache_instance_t *ctx, server_rec *s,

                                        const unsigned char *id, unsigned int idlen,

                                        unsigned char *dest, unsigned int *destlen,

                                        apr_pool_t *p)

{

    unsigned int data_len;

    /* Retrieve any corresponding session from the distributed cache context */

    if (!DC_CTX_get_session(ctx->dc, id, idlen, dest, *destlen, &data_len)) {

        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00742) "distributed scache 'retrieve' MISS");

        return APR_NOTFOUND;

    }

    if (data_len > *destlen) {

        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(00743) "distributed scache 'retrieve' OVERFLOW");

        return APR_ENOSPC;

    }

    *destlen = data_len;

    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00744) "distributed scache 'retrieve' HIT");

    return APR_SUCCESS;

}

static apr_status_t socache_dc_remove(ap_socache_instance_t *ctx,

                                      server_rec *s, const unsigned char *id,

                                      unsigned int idlen, apr_pool_t *p)

{

    /* Remove any corresponding session from the distributed cache context */

    if (!DC_CTX_remove_session(ctx->dc, id, idlen)) {

        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(00745) "distributed scache 'remove' MISS");

        return APR_NOTFOUND;

    }

    else {

        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(00746) "distributed scache 'remove' HIT");

        return APR_SUCCESS;

    }

}

static void socache_dc_status(ap_socache_instance_t *ctx, request_rec *r, int flags)

{

    ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00747)

                  "distributed scache 'socache_dc_status'");

    if (!(flags & AP_STATUS_SHORT)) {

        ap_rprintf(r, "cache type: DC (Distributed Cache), "

                   " target: %s
", ctx->target);

    }

    else {

        ap_rputs("CacheType: DC\n", r);

        ap_rvputs(r, "CacheTarget: ", ctx->target, "\n", NULL);

    }

}

static apr_status_t socache_dc_iterate(ap_socache_instance_t *instance,

                                       server_rec *s, void *userctx,

                                       ap_socache_iterator_t *iterator,

                                       apr_pool_t *pool)

{

    return APR_ENOTIMPL;

}

static const ap_socache_provider_t socache_dc = {

    "distcache",

    0,

    socache_dc_create,

    socache_dc_init,

    socache_dc_destroy,

    socache_dc_store,

    socache_dc_retrieve,

    socache_dc_remove,

    socache_dc_status,

    socache_dc_iterate

};

static void register_hooks(apr_pool_t *p)

{

    ap_register_provider(p, AP_SOCACHE_PROVIDER_GROUP, "dc",

                         AP_SOCACHE_PROVIDER_VERSION,

                         &socache_dc);

}

AP_DECLARE_MODULE(socache_dc) = {

    STANDARD20_MODULE_STUFF,

    NULL, NULL, NULL, NULL, NULL,

    register_hooks

};