3 /* messaging - high level communication (send/receive messages) */
4 /* module's public interface exported to end user. */
6 /* Copyright (c) 2003-2007 Martin Quinson. All rights reserved. */
8 /* This program is free software; you can redistribute it and/or modify it
9 * under the terms of the license (GNU LGPL) which comes with this package. */
11 #ifndef GRAS_MESSAGES_H
12 #define GRAS_MESSAGES_H
15 #include "gras/transport.h"
16 #include "gras/datadesc.h"
20 /** @addtogroup GRAS_msg
21 * @brief Defining messages and callbacks, and exchanging messages
23 * There is two way to receive messages in GRAS. The first one is to
24 * register a given function as callback to a given type of messages (see
25 * \ref gras_cb_register and associated section). But you can also
26 * explicitely wait for a given message with the \ref gras_msg_wait
29 * Usually, both ways are not intended to be mixed of a given type of
30 * messages. But if you do so, it shouldn't trigger any issue. If the
31 * message arrives when gras_msg_wait is blocked, then it will be routed to
32 * it. If it arrives when before or after \ref gras_msg_wait, it will be
33 * passed to the callback.
35 * For an example of use, please refer to \ref GRAS_ex_ping. The archive
36 * contains much more examples, but their are not properly integrated into
37 * this documentation yet.
40 /** @defgroup GRAS_msg_decl Message declaration and retrival
43 * GRAS messages can only accept one type of payload. See \ref GRAS_dd for
44 * more information on how to describe data in GRAS.
46 * If you absolutely want use a message able to convey several datatypes,
47 * you can always say that it conveys a generic reference (see
48 * \ref gras_datadesc_ref_generic).
50 * In order to ease the upgrade of GRAS applications, it is possible to \e
51 * version the messages, ie to add a version number to the message (by
52 * default, the version is set to 0). Any messages of the wrong version will
53 * be ignored by the applications not providing any specific callback for
56 * This mechanism (stolen from the dynamic loader one) should ensure you to
57 * change the semantic of a given message while still understanding the old
61 /** \brief Opaque type */
62 typedef struct s_gras_msgtype *gras_msgtype_t;
64 XBT_PUBLIC(void) gras_msgtype_declare (const char *name,
65 gras_datadesc_type_t payload);
66 XBT_PUBLIC(void) gras_msgtype_declare_v(const char *name,
68 gras_datadesc_type_t payload);
70 XBT_PUBLIC(gras_msgtype_t) gras_msgtype_by_name (const char *name);
71 XBT_PUBLIC(gras_msgtype_t) gras_msgtype_by_name_or_null (const char *name);
72 XBT_PUBLIC(gras_msgtype_t) gras_msgtype_by_namev(const char *name, short int version);
73 XBT_PUBLIC(gras_msgtype_t) gras_msgtype_by_id(int id);
75 XBT_PUBLIC(void) gras_msgtype_dumpall(void);
79 /** @defgroup GRAS_msg_cb Callback declaration and use
83 * This is how to register a given function so that it gets called when a
84 * given type of message arrives.
86 * You can register several callbacks to the same kind of messages, and
87 * they will get stacked. The lastly added callback gets the message first.
88 * If it consumes the message, it should return a true value when done. If
89 * not, it should return 0, and the message will be passed to the second
90 * callback of the stack, if any.
95 /** \brief Context of callbacks (opaque structure, created by the middleware only, never by user) */
96 typedef struct s_gras_msg_cb_ctx *gras_msg_cb_ctx_t;
98 XBT_PUBLIC(void) gras_msg_cb_ctx_free(gras_msg_cb_ctx_t ctx) ;
99 XBT_PUBLIC(gras_socket_t) gras_msg_cb_ctx_from(gras_msg_cb_ctx_t ctx);
101 /** \brief Type of message callback functions.
103 * \param expeditor: a socket to contact who sent this message
104 * \param payload: the message itself
106 * \return true if the message was consumed by the callback,
107 * false if the message was refused by the callback (and should be
108 * passed to the next callback of the stack for this message)
110 * Once a such a function is registered to handle messages of a given
111 * type with \ref gras_cb_register(), it will be called each time such
112 * a message arrives (unless a gras_msg_wait() intercepts it on arrival).
114 * If the callback accepts the message, it should free it after use.
116 typedef int (*gras_msg_cb_t)(gras_msg_cb_ctx_t ctx,
120 * @brief Bind the given callback to the given message type (described by its name)
123 * Several callbacks can be attached to a given message type. The lastly added one will get the message first, and
124 * if it returns a non-null value, the message will be passed to the second one.
125 * And so on until one of the callbacks accepts the message.
127 * Using gras_cb_register is a bit slower than using gras_cb_register_ since GRAS
128 * has to search for the given msgtype in the hash table, but you don't care in most case.
130 #define gras_cb_register(msgtype_name, cb) gras_cb_register_(gras_msgtype_by_name(msgtype_name),cb)
133 * @brief Unbind the given callback to the given message type (described by its name)
136 * Using gras_cb_unregister is a bit slower than using gras_cb_unregister_ since GRAS
137 * has to search for the given msgtype in the hash table, but you don't care in most case.
139 #define gras_cb_unregister(msgtype_name, cb) gras_cb_unregister_(gras_msgtype_by_name(msgtype_name),cb)
141 XBT_PUBLIC(void) gras_cb_register_ (gras_msgtype_t msgtype, gras_msg_cb_t cb);
142 XBT_PUBLIC(void) gras_cb_unregister_(gras_msgtype_t msgtype, gras_msg_cb_t cb);
146 /** @defgroup GRAS_msg_exchange Message exchange
152 /** \brief Send the data pointed by \a payload as a message \a msgname on the \a sock
155 * Using gras_msg_wait() is a bit slower than using gras_msg_wait_() since GRAS
156 * has to search for the given msgtype in the hash table.
158 #define gras_msg_send(sock,name,payload) gras_msg_send_(sock,gras_msgtype_by_name(name),payload)
159 XBT_PUBLIC(void) gras_msg_send_(gras_socket_t sock,
160 gras_msgtype_t msgtype,
163 /** \brief Waits for a message to come in over a given socket
165 * @param timeout: How long should we wait for this message.
166 * @param msgt_want: type of awaited msg
167 * @param[out] expeditor: where to create a socket to answer the incomming message
168 * @param[out] payload: where to write the payload of the incomming message
169 * @return the error code (or no_error).
171 * Every message of another type received before the one waited will be queued
172 * and used by subsequent call to this function or gras_msg_handle().
174 * Using gras_msg_wait() is a bit slower than using gras_msg_wait_() since GRAS
175 * has to search for the given msgtype in the hash table.
178 #define gras_msg_wait(timeout,msgt_want,expeditor,payload) gras_msg_wait_(timeout,gras_msgtype_by_name(msgt_want),expeditor,payload)
179 XBT_PUBLIC(void) gras_msg_wait_(double timeout,
180 gras_msgtype_t msgt_want,
181 gras_socket_t *expeditor,
183 XBT_PUBLIC(void) gras_msg_handleall(double period);
184 XBT_PUBLIC(void) gras_msg_handle(double timeOut);
188 /** @defgroup GRAS_msg_rpc RPC specific functions
191 * Remote Procedure Call (RPC) are a classical mecanism to request a service
192 * from a remote host. Using this set of functions, you let GRAS doing most of
193 * the work of sending the request, wait for an answer, make sure it is the
194 * right answer from the right host and so on. Any exception raised on the
195 * server is also passed over the network to the client.
197 * Callbacks are attached to RPC incomming messages the regular way using
198 * \ref gras_cb_register.
200 * For an example of use, check the examples/gras/rpc directory of the distribution.
205 XBT_PUBLIC(void) gras_msgtype_declare_rpc(const char *name,
206 gras_datadesc_type_t payload_request,
207 gras_datadesc_type_t payload_answer);
209 XBT_PUBLIC(void) gras_msgtype_declare_rpc_v(const char *name,
211 gras_datadesc_type_t payload_request,
212 gras_datadesc_type_t payload_answer);
216 /** @brief Conduct a RPC call
219 #define gras_msg_rpccall(server,timeout,msg,req,ans) gras_msg_rpccall_(server,timeout,gras_msgtype_by_name(msg),req,ans)
220 XBT_PUBLIC(void) gras_msg_rpccall_(gras_socket_t server,
222 gras_msgtype_t msgtype,
223 void *request, void *answer);
224 XBT_PUBLIC(gras_msg_cb_ctx_t)
226 /** @brief Launch a RPC call, but do not block for the answer
230 #define gras_msg_rpc_async_call(server,timeout,msg,req) gras_msg_rpc_async_call_(server,timeout,gras_msgtype_by_name(msg),req)
231 gras_msg_rpc_async_call_(gras_socket_t server,
233 gras_msgtype_t msgtype,
235 XBT_PUBLIC(void) gras_msg_rpc_async_wait(gras_msg_cb_ctx_t ctx,
239 XBT_PUBLIC(void) gras_msg_rpcreturn(double timeOut, gras_msg_cb_ctx_t ctx,void *answer);
244 /** @defgroup GRAS_msg_exchangeadv Message exchange (advanced interface)
250 /** @brief Message kind (internal enum) */
252 e_gras_msg_kind_unknown = 0,
254 e_gras_msg_kind_oneway=1, /**< good old regular messages */
256 e_gras_msg_kind_rpccall=2, /**< RPC request */
257 /* HACK: e_gras_msg_kind_rpccall also designate RPC message *type* in
258 msgtype_t, not only in msg_t*/
259 e_gras_msg_kind_rpcanswer=3, /**< RPC successful answer */
260 e_gras_msg_kind_rpcerror=4, /**< RPC failure on server (payload=exception); should not leak to user-space */
263 call cancel, and others
265 forwarding request and other application level routing stuff
269 e_gras_msg_kind_count=5 /* sentinel, dont mess with */
273 /** @brief Message instance (internal struct) */
276 e_gras_msg_kind_t kind;
278 unsigned long int ID;
281 } s_gras_msg_t, *gras_msg_t;
283 typedef int (*gras_msg_filter_t)(gras_msg_t msg,void *ctx);
285 #define gras_msg_wait_ext(timeout, msg, expe, filter, fctx,got) gras_msg_wait_ext_(timeout, gras_msgtype_by_name(msg), expe, filter, fctx,got)
286 XBT_PUBLIC(void) gras_msg_wait_ext_(double timeout,
287 gras_msgtype_t msgt_want,
288 gras_socket_t expe_want,
289 gras_msg_filter_t filter,
293 XBT_PUBLIC(void) gras_msg_wait_or(double timeout,
294 xbt_dynar_t msgt_want,
295 gras_msg_cb_ctx_t *ctx,
304 #endif /* GRAS_MSG_H */