/lib/mosquitto_internal.h
struct mosquitto { //结构体struct mosquito主要用于保存一个客户端连接的所有信息，例如用户名、密码、用户ID、向该客户端发送的消息等 mosq_sock_t sock; /*服务器程序与该客户端连接通信所用的socket描述符*/ #ifndef WITH_BROKER mosq_sock_t sockpairR, sockpairW; #endif #if defined(__GLIBC__) && defined(WITH_ADNS) struct gaicb *adns; /* For getaddrinfo_a */ #endif enum mosquitto__protocol protocol; char *address; /*该客户端的IP地址*/ char *id; /*该客户端登陆mosquitto程序时所提供的ID值，该值与其他的客户端不能重复*/ char *username; char *password; uint16_t keepalive; /*该客户端需在此时间内向mosquitto服务器程序发送一条ping/pong消息*/ uint16_t last_mid; enum mosquitto_client_state state; time_t last_msg_in; /*last_msg_in和last_msg_out用于记录上次收发消息的时间*/ time_t next_msg_out; time_t ping_t; struct mosquitto__packet in_packet; struct mosquitto__packet *current_out_packet; struct mosquitto__packet *out_packet; struct mosquitto_message *will; ......
/src/mosquitto_broker_internal.h
struct mosquitto__subleaf { //firecat,leaf叶子,对某一topic的所有订阅者被组织成一个订阅列表，该订阅列表是一个双向链表，链表的每个节点都保存有一个订阅者 struct mosquitto__subleaf *prev; /*前指针*/ struct mosquitto__subleaf *next; /*后指针*/ struct mosquitto *context; /*表示一个订阅客户端*/ int qos; /* Qos Level */ }; struct mosquitto__subhier { //用来保存订阅树的所有节点（包括叶子节点和中间节点），mosquitto中对订阅树采用孩子-兄弟链表法的方式进行存储 UT_hash_handle hh; struct mosquitto__subhier *parent; struct mosquitto__subhier *children; /*第一个孩子节点*/ struct mosquitto__subleaf *subs; /*指向订阅列表*/ struct mosquitto_msg_store *retained; mosquitto__topic_element_uhpa topic; /*订阅主题*/ uint16_t topic_len; }; struct mosquitto_db{ //结构体struct mosquitto_db是mosquitto对所有内部数据的统一管理结构，可以认为是其内部的一个内存数据库。 //它保存了所有的客户端，所有客户端的订阅关系等等 dbid_t last_db_id; struct mosquitto__subhier *subs; /*订阅树的总树根*/ struct mosquitto__unpwd *unpwd; struct mosquitto__unpwd *psk_id; struct mosquitto *contexts_by_id; /*所有的客户端都在此数组中保存*/ struct mosquitto *contexts_by_sock; struct mosquitto *contexts_for_free; #ifdef WITH_BRIDGE struct mosquitto **bridges; #endif struct clientid__index_hash *clientid_index_hash; /*用于保存一个hash表，该hash表可通过客户端的ID快速找到该客户端在数组contexts中的索引*/ struct mosquitto_msg_store *msg_store; struct mosquitto_msg_store_load *msg_store_load; #ifdef WITH_BRIDGE int bridge_count; #endif int msg_store_count; unsigned long msg_store_bytes; char *config_file; struct mosquitto__config *config; /*保存所有配置信息*/ int auth_plugin_count; bool verbose; #ifdef WITH_SYS_TREE int subscription_count; int retained_count; #endif int persistence_changes; struct mosquitto *ll_for_free; #ifdef WITH_EPOLL int epollfd; #endif };
