evrpc-internal.h

/*
 * Copyright (c) 2006-2007 Niels Provos <provos@citi.umich.edu>
 * Copyright (c) 2007-2012 Niels Provos and Nick Mathewson
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#ifndef EVRPC_INTERNAL_H_INCLUDED_
#define EVRPC_INTERNAL_H_INCLUDED_
 
#include "event2/http.h"
#include "http-internal.h"
 
struct evrpc;
struct evrpc_request_wrapper;
 
#define EVRPC_URI_PREFIX "/.rpc."
 
struct evrpc_hook {
    TAILQ_ENTRY(evrpc_hook) next;
 
    /* returns EVRPC_TERMINATE; if the rpc should be aborted.
     * a hook is is allowed to rewrite the evbuffer
     */
    int (*process)(void *, struct evhttp_request *,
        struct evbuffer *, void *);
    void *process_arg;
};
 
TAILQ_HEAD(evrpc_hook_list, evrpc_hook);
 
/*
 * this is shared between the base and the pool, so that we can reuse
 * the hook adding functions; we alias both evrpc_pool and evrpc_base
 * to this common structure.
 */
 
struct evrpc_hook_ctx;
TAILQ_HEAD(evrpc_pause_list, evrpc_hook_ctx);
 
struct evrpc_hooks_ {
    /* hooks for processing outbound and inbound rpcs */
    struct evrpc_hook_list in_hooks;
    struct evrpc_hook_list out_hooks;
 
    struct evrpc_pause_list pause_requests;
};
 
#define input_hooks common.in_hooks
#define output_hooks common.out_hooks
#define paused_requests common.pause_requests
 
struct evrpc_base {
    struct evrpc_hooks_ common;
 
    /* the HTTP server under which we register our RPC calls */
    struct evhttp* http_server;
 
    /* a list of all RPCs registered with us */
    TAILQ_HEAD(evrpc_list, evrpc) registered_rpcs;
};
 
struct evrpc_req_generic;
void evrpc_reqstate_free_(struct evrpc_req_generic* rpc_state);
 
/* A pool for holding evhttp_connection objects */
struct evrpc_pool {
    struct evrpc_hooks_ common;
 
    struct event_base *base;
 
    struct evconq connections;
 
    int timeout;
 
    TAILQ_HEAD(evrpc_requestq, evrpc_request_wrapper) (requests);
};
 
struct evrpc_hook_ctx {
    TAILQ_ENTRY(evrpc_hook_ctx) next;
 
    void *ctx;
    void (*cb)(void *, enum EVRPC_HOOK_RESULT);
};
 
struct evrpc_meta {
    TAILQ_ENTRY(evrpc_meta) next;
    char *key;
 
    void *data;
    size_t data_size;
};
 
TAILQ_HEAD(evrpc_meta_list, evrpc_meta);
 
struct evrpc_hook_meta {
    struct evrpc_meta_list meta_data;
    struct evhttp_connection *evcon;
};
 
/* allows association of meta data with a request */
static void evrpc_hook_associate_meta_(struct evrpc_hook_meta **pctx,
    struct evhttp_connection *evcon);
 
/* creates a new meta data store */
static struct evrpc_hook_meta *evrpc_hook_meta_new_(void);
 
/* frees the meta data associated with a request */
static void evrpc_hook_context_free_(struct evrpc_hook_meta *ctx);
 
/* the server side of an rpc */
 
/* We alias the RPC specific structs to this voided one */
struct evrpc_req_generic {
    /*
     * allows association of meta data via hooks - needs to be
     * synchronized with evrpc_request_wrapper
     */
    struct evrpc_hook_meta *hook_meta;
 
    /* the unmarshaled request object */
    void *request;
 
    /* the empty reply object that needs to be filled in */
    void *reply;
 
    /*
     * the static structure for this rpc; that can be used to
     * automatically unmarshal and marshal the http buffers.
     */
    struct evrpc *rpc;
 
    /*
     * the http request structure on which we need to answer.
     */
    struct evhttp_request* http_req;
 
    /*
     * Temporary data store for marshaled data
     */
    struct evbuffer* rpc_data;
};
 
/* the client side of an rpc request */
struct evrpc_request_wrapper {
    /*
     * allows association of meta data via hooks - needs to be
     * synchronized with evrpc_req_generic.
     */
    struct evrpc_hook_meta *hook_meta;
 
    TAILQ_ENTRY(evrpc_request_wrapper) next;
 
    /* pool on which this rpc request is being made */
    struct evrpc_pool *pool;
 
    /* connection on which the request is being sent */
    struct evhttp_connection *evcon;
 
    /* the actual  request */
    struct evhttp_request *req;
 
    /* event for implementing request timeouts */
    struct event ev_timeout;
 
    /* the name of the rpc */
    char *name;
 
    /* callback */
    void (*cb)(struct evrpc_status*, void *request, void *reply, void *arg);
    void *cb_arg;
 
    void *request;
    void *reply;
 
    /* unmarshals the buffer into the proper request structure */
    void (*request_marshal)(struct evbuffer *, void *);
 
    /* removes all stored state in the reply */
    void (*reply_clear)(void *);
 
    /* marshals the reply into a buffer */
    int (*reply_unmarshal)(void *, struct evbuffer*);
};
 
#endif /* EVRPC_INTERNAL_H_INCLUDED_ */