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   1 /* LibMemcached
   2  * Copyright (C) 2006-2009 Brian Aker
   3  * All rights reserved.
   4  *
   5  * Use and distribution licensed under the BSD license.  See
   6  * the COPYING file in the parent directory for full text.
   7  *
   8  * Summary: Definition of the callback interface to the protocol handler
   9  *
  10  * Author: Trond Norbye
  11  *
  12  */
  13
  14 #ifndef __LIBMEMCACHED_PROTOCOL_H__
  15 #define __LIBMEMCACHED_PROTOCOL_H__
  16
  17 #include <sys/types.h>
  18 #if !defined(__cplusplus)
  19 # include <stdbool.h>
  20 #endif
  21
  22 #include <libmemcached/memcached/protocol_binary.h>
  23 #include <libmemcached/visibility.h>
  24 #include <libmemcached/protocol/callback.h>
  25
  26 /* Forward declarations */
  27 /*
  28  * You should only access memcached_protocol_st from one thread!,
  29  * and never assume anything about the internal layout / sizes of the
  30  * structures.
  31  */
  32 typedef struct memcached_protocol_st memcached_protocol_st;
  33 typedef struct memcached_protocol_client_st memcached_protocol_client_st;
  34
  35 #ifdef __cplusplus
  36 extern "C" {
  37 #endif
  38
  39 /**
  40  * Function the protocol handler should call to receive data.
  41  * This function should behave exactly like read(2)
  42  *
  43  * @param cookie a cookie used to represent a given client
  44  * @param fd the filedescriptor associated with the client
  45  * @param buf destination buffer
  46  * @param nbuf number of bytes to receive
  47  * @return the number of bytes copied into buf
  48  *         or -1 upon error (errno should contain more information)
  49  */
  50 typedef ssize_t (*memcached_protocol_recv_func)(const void *cookie,
  51                                                 int fd,
  52                                                 void *buf,
  53                                                 size_t nbuf);
  54
  55 /**
  56  * Function the protocol handler should call to send data.
  57  * This function should behave exactly like write(2)
  58  *
  59  * @param cookie a cookie used to represent a given client
  60  * @param fd the filedescriptor associated with the client
  61  * @param buf the source buffer
  62  * @param nbuf number of bytes to send
  63  * @return the number of bytes sent
  64  *         or -1 upon error (errno should contain more information)
  65  */
  66 typedef ssize_t (*memcached_protocol_send_func)(const void *cookie,
  67                                                 int fd,
  68                                                 const void *buf,
  69                                                 size_t nbuf);
  70
  71 /**
  72  * Create an instance of the protocol handler
  73  *
  74  * @return NULL if allocation of an instance fails
  75  */
  76 LIBMEMCACHED_API
  77 memcached_protocol_st *memcached_protocol_create_instance(void);
  78
  79 /**
  80  * Get the callbacks associated with a protocol handler instance
  81  * @return the callbacks currently used
  82  */
  83 LIBMEMCACHED_API
  84 memcached_binary_protocol_callback_st *memcached_binary_protocol_get_callbacks(memcached_protocol_st *instance);
  85
  86 /**
  87  * Set the callbacks to be used by the given protocol handler instance
  88  * @param instance the instance to update
  89  * @param callback the callbacks to use
  90  */
  91 LIBMEMCACHED_API
  92 void memcached_binary_protocol_set_callbacks(memcached_protocol_st *instance, memcached_binary_protocol_callback_st *callback);
  93
  94 /**
  95  * Should the library inspect the packages being sent and received and verify
  96  * that they are according to the specification? If it encounters an invalid
  97  * packet, it will return an EINVAL packet.
  98  *
  99  * @param instance the instance to update
 100  * @param enable true if you want the library to check packages, false otherwise
 101  */
 102 LIBMEMCACHED_API
 103 void memcached_binary_protocol_set_pedantic(memcached_protocol_st *instance, bool enable);
 104
 105 /**
 106  * Is the library inpecting each package?
 107  * @param instance the instance to check
 108  * @return true it the library is inspecting each package, false otherwise
 109  */
 110 LIBMEMCACHED_API
 111 bool memcached_binary_protocol_get_pedantic(memcached_protocol_st *instance);
 112
 113 /**
 114  * Destroy an instance of the protocol handler
 115  *
 116  * @param instance The instance to destroy
 117  */
 118 LIBMEMCACHED_API
 119 void memcached_protocol_destroy_instance(memcached_protocol_st *instance);
 120
 121 /**
 122  * Set the IO functions used by the instance to send and receive data. The
 123  * functions should behave like recv(3socket) and send(3socket).
 124  *
 125  * @param instance the instance to specify the IO functions for
 126  * @param recv the function to call for reciving data
 127  * @param send the function to call for sending data
 128  */
 129 LIBMEMCACHED_API
 130 void memached_protocol_set_io_functions(memcached_protocol_st *instance,
 131                                         memcached_protocol_recv_func recv,
 132                                         memcached_protocol_send_func send);
 133
 134
 135 /**
 136  * Create a new client instance and associate it with a socket
 137  * @param instance the protocol instance to bind the client to
 138  * @param sock the client socket
 139  * @return NULL if allocation fails, otherwise an instance
 140  */
 141 LIBMEMCACHED_API
 142 memcached_protocol_client_st *memcached_protocol_create_client(memcached_protocol_st *instance, int sock);
 143
 144 /**
 145  * Destroy a client handle.
 146  * The caller needs to close the socket accociated with the client
 147  * <b>before</b> calling this function. This function invalidates the
 148  * client memory area.
 149  *
 150  * @param client the client to destroy
 151  */
 152 LIBMEMCACHED_API
 153 void memcached_protocol_client_destroy(memcached_protocol_client_st *client);
 154
 155 /**
 156  * Error event means that the client encountered an error with the
 157  * connection so you should shut it down
 158  */
 159 #define MEMCACHED_PROTOCOL_ERROR_EVENT 1
 160 /**
 161  * Please notify when there is more data available to read
 162  */
 163 #define MEMCACHED_PROTOCOL_READ_EVENT 2
 164 /**
 165  * Please notify when it is possible to send more data
 166  */
 167 #define MEMCACHED_PROTOCOL_WRITE_EVENT 4
 168 /**
 169  * Backed paused the execution for this client
 170  */
 171 #define MEMCACHED_PROTOCOL_PAUSE_EVENT 8
 172
 173 /**
 174  * The different events the client is interested in. This is a bitmask of
 175  * the constants defined above.
 176  */
 177 typedef uint32_t memcached_protocol_event_t;
 178
 179 /**
 180  * Let the client do some work. This might involve reading / sending data
 181  * to/from the client, or perform callbacks to execute a command.
 182  * @param client the client structure to work on
 183  * @return The next event the protocol handler will be notified for
 184  */
 185 LIBMEMCACHED_API
 186 memcached_protocol_event_t memcached_protocol_client_work(memcached_protocol_client_st *client);
 187
 188 /**
 189  * Get the socket attached to a client handle
 190  * @param client the client to query
 191  * @return the socket handle
 192  */
 193 LIBMEMCACHED_API
 194 int memcached_protocol_client_get_socket(memcached_protocol_client_st *client);
 195
 196 /**
 197  * Get the error id socket attached to a client handle
 198  * @param client the client to query for an error code
 199  * @return the OS error code from the client
 200  */
 201 LIBMEMCACHED_API
 202 int memcached_protocol_client_get_errno(memcached_protocol_client_st *client);
 203
 204 /**
 205  * Get a raw response handler for the given cookie
 206  * @param cookie the cookie passed along into the callback
 207  * @return the raw reponse handler you may use if you find
 208  *         the generic callback too limiting
 209  */
 210 LIBMEMCACHED_API
 211 memcached_binary_protocol_raw_response_handler memcached_binary_protocol_get_raw_response_handler(const void *cookie);
 212
 213 #ifdef __cplusplus
 214 }
 215 #endif
 216
 217 #endif