Added redis-style EXISTS command support

README

@@ -45,8 +45,9 @@
   Start as server
   ===============
   	* $./nessdb-server
-	Now you can use redis-cli(or other redis's clients) to do some "COMMAND" operations(Now support:PING,SET,MSET,GET,MGET,DEL,INFO commands).
+	Now you can use redis-cli(or other redis's clients) to do some "COMMAND" operations
+	(Support Redis-Style commands:PING,SET,MSET,GET,MGET,DEL,EXISTS,INFO).
 
-Thanks.
+ Thanks.
 
-== END OF FILE ==
+ == END OF FILE ==

src/db.c

@@ -193,6 +193,12 @@ void *db_get(const char *key)
 	}
 }
 
+int db_exists(const char *key)
+{
+	unsigned int slot=jdb_hash(key)%DB_SLOT;
+	return btree_get_index(&_btrees[slot],key);
+}
+
 void db_remove(const char *key)
 {
 	int result;

src/db.h

@@ -12,7 +12,7 @@ extern "C" {
 void 	db_init(int bufferpool_size,int isbgsync);
 
 void	*db_get(const char *key);
-
+int	db_exists(const char *key);
 int 	db_add(const char *key,const char *value);
 void	db_update(const char *key,const char *value);
 void	db_remove(const char *key);

src/nessdb-server.c

@@ -265,6 +265,14 @@ void read_handler(aeEventLoop *el, int fd, void *privdata, int mask)
 						response_free(resp);
 						break;
 					     }
+				case CMD_EXISTS:{
+						 int ret= db_exists(req->argv[1]);
+						 if(ret)
+							write(fd,":1\r\n",4);
+						 else
+							write(fd,":-1\r\n",5);
+						}
+						break;
 
 				default:{
 						resp=response_new(0,ERR);

src/request.c

@@ -90,6 +90,7 @@ static const struct cmds _cmds[]=
 	{"mset",CMD_MSET},
 	{"del",CMD_DEL},
 	{"info",CMD_INFO},
+	{"exists",CMD_EXISTS},
 	{"unknow cmd",CMD_UNKNOW}
 };
 

src/request.h

@@ -1,7 +1,7 @@
 #ifndef _REQUEST_H
 #define _REQUEST_H
 
-typedef enum{CMD_PING,CMD_GET,CMD_MGET,CMD_SET,CMD_MSET,CMD_DEL,CMD_INFO,CMD_UNKNOW}CMD;
+typedef enum{CMD_PING,CMD_GET,CMD_MGET,CMD_SET,CMD_MSET,CMD_DEL,CMD_INFO,CMD_EXISTS,CMD_UNKNOW}CMD;
 
 struct  cmds{
 	char method[256];