Function moduleTryServeClientBlockedOnKey

app/redis-6.2.6/src/module.c:5335–5355

This function is called from module.c in order to check if a module * blocked for BLOCKED_MODULE and subtype 'on keys' (bc->blocked_on_keys true) * can really be unblocked, since the module was able to serve the client. * If the callback returns REDISMODULE_OK, then the client can be unblocked, * otherwise the client remains blocked and we'll retry again when one of * the keys it blocked for

 * the keys it blocked for becomes "ready" again.
 * This function returns 1 if client was served (and should be unblocked) */
int moduleTryServeClientBlockedOnKey(client *c, robj *key) {
    int served = 0;
    RedisModuleBlockedClient *bc = c->bpop.module_blocked_handle;

    /* Protect against re-processing: don't serve clients that are already
     * in the unblocking list for any reason (including RM_UnblockClient()
     * explicit call). See #6798. */
    if (bc->unblocked) return 0;

    RedisModuleCtx ctx = REDISMODULE_CTX_INIT;
    ctx.flags |= REDISMODULE_CTX_BLOCKED_REPLY;
    ctx.blocked_ready_key = key;
    ctx.blocked_privdata = bc->privdata;
    ctx.module = bc->module;
    ctx.client = bc->client;
    ctx.blocked_client = bc;
    if (bc->reply_callback(&ctx,(void**)c->argv,c->argc) == REDISMODULE_OK)
        served = 1;
    moduleFreeContext(&ctx);
    return served;
}

/* Block a client in the context of a blocking command, returning an handle
 * which will be used, later, in order to unblock the client with a call to