polardbxengine/plugin/innodb_memcached/daemon_memcached/extensions/protocol/example_protocol.c

116 lines
4.1 KiB
C

/* -*- Mode: C; tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*- */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "protocol_extension.h"
/*
* This is an example on how you can add your own commands into the
* ascii protocol. You load the extensions into memcached by using
* the -X option:
* ./memcached -X .libs/example_protocol.so -E .libs/default_engine.so
*
* @todo add an example that require extra userspace data, and communicates
* with the engine by getting the engine descriptor.
*/
static const char *get_name(const void *cmd_cookie);
static bool accept_command(const void *cmd_cookie, void *cookie,
int argc, token_t *argv, size_t *ndata,
char **ptr);
static ENGINE_ERROR_CODE execute_command(const void *cmd_cookie, const void *cookie,
int argc, token_t *argv,
ENGINE_ERROR_CODE (*response_handler)(const void *cookie,
int nbytes,
const char *dta));
static void abort_command(const void *cmd_cookie, const void *cookie);
static EXTENSION_ASCII_PROTOCOL_DESCRIPTOR noop_descriptor = {
.get_name = get_name,
.accept = accept_command,
.execute = execute_command,
.abort = abort_command,
.cookie = &noop_descriptor
};
static EXTENSION_ASCII_PROTOCOL_DESCRIPTOR echo_descriptor = {
.get_name = get_name,
.accept = accept_command,
.execute = execute_command,
.abort = abort_command,
.cookie = &echo_descriptor
};
static const char *get_name(const void *cmd_cookie) {
if (cmd_cookie == &noop_descriptor) {
return "noop";
} else {
return "echo";
}
}
static bool accept_command(const void *cmd_cookie, void *cookie,
int argc, token_t *argv, size_t *ndata,
char **ptr) {
if (cmd_cookie == &noop_descriptor) {
return strcmp(argv[0].value, "noop") == 0;
} else {
return strcmp(argv[0].value, "echo") == 0;
}
}
static ENGINE_ERROR_CODE execute_command(const void *cmd_cookie, const void *cookie,
int argc, token_t *argv,
ENGINE_ERROR_CODE (*response_handler)(const void *cookie,
int nbytes,
const char *dta))
{
if (cmd_cookie == &noop_descriptor) {
return response_handler(cookie, 4, "OK\r\n");
} else {
if (response_handler(cookie, argv[0].length, argv[0].value) != ENGINE_SUCCESS) {
return ENGINE_DISCONNECT;
}
for (int ii = 1; ii < argc; ++ii) {
if (response_handler(cookie, 2, " [") != ENGINE_SUCCESS ||
response_handler(cookie, argv[ii].length, argv[ii].value) != ENGINE_SUCCESS ||
response_handler(cookie, 1, "]") != ENGINE_SUCCESS) {
return ENGINE_DISCONNECT;
}
}
return response_handler(cookie, 2, "\r\n");
}
}
static void abort_command(const void *cmd_cookie, const void *cookie)
{
/* EMPTY */
}
#if defined (__SUNPRO_C) && (__SUNPRO_C >= 0x550)
__global
#elif defined __GNUC__
__attribute__ ((visibility("default")))
#endif
EXTENSION_ERROR_CODE memcached_extensions_initialize(const char *config,
GET_SERVER_API get_server_api) {
SERVER_HANDLE_V1 *server = get_server_api();
if (server == NULL) {
return EXTENSION_FATAL;
}
if (!server->extension->register_extension(EXTENSION_ASCII_PROTOCOL,
&noop_descriptor)) {
return EXTENSION_FATAL;
}
if (!server->extension->register_extension(EXTENSION_ASCII_PROTOCOL,
&echo_descriptor)) {
return EXTENSION_FATAL;
}
return EXTENSION_SUCCESS;
}