Function _addReplyToBuffer

src/networking.cpp:352–396

Attempts to add the reply to the static buffer in the client struct. * Returns C_ERR if the buffer is full, or the reply list is not empty, * in which case the reply must be added to the reply list. */

 * Returns C_ERR if the buffer is full, or the reply list is not empty,
 * in which case the reply must be added to the reply list. */
int _addReplyToBuffer(client *c, const char *s, size_t len) {
    if (c->flags.load(std::memory_order_relaxed) & CLIENT_CLOSE_AFTER_REPLY) return C_OK;

    bool fAsync = !FCorrectThread(c);
    if (fAsync)
    {
        serverAssert(GlobalLocksAcquired());
        if (c->replyAsync == nullptr || (c->replyAsync->size - c->replyAsync->used) < len)
        {
            if (c->replyAsync == nullptr) {
                size_t newsize = std::max(len, (size_t)PROTO_ASYNC_REPLY_CHUNK_BYTES);
                    
                clientReplyBlock *replyNew = (clientReplyBlock*)zmalloc(sizeof(clientReplyBlock) + newsize);
                replyNew->size = zmalloc_usable_size(replyNew) - sizeof(clientReplyBlock);
                replyNew->used = 0;
                c->replyAsync = replyNew;
            } else {
                size_t newsize = std::max(c->replyAsync->used + len, c->replyAsync->size*2);
                clientReplyBlock *replyNew = (clientReplyBlock*)zmalloc(sizeof(clientReplyBlock) + newsize);
                replyNew->size = zmalloc_usable_size(replyNew) - sizeof(clientReplyBlock);
                replyNew->used = c->replyAsync->used;
                memcpy(replyNew->buf(), c->replyAsync->buf(), c->replyAsync->used);
                zfree(c->replyAsync);
                c->replyAsync = replyNew;
            }
        }
        memcpy(c->replyAsync->buf() + c->replyAsync->used,s,len);
        c->replyAsync->used += len;
    }
    else
    {
        size_t available = sizeof(c->buf)-c->bufpos;

        /* If there already are entries in the reply list, we cannot
        * add anything more to the static buffer. */
        if (listLength(c->reply) > 0) return C_ERR;

        /* Check that the buffer has enough space available for this string. */
        if (len > available) return C_ERR;

        memcpy(c->buf+c->bufpos,s,len);
        c->bufpos+=len;
    }
    return C_OK;
}

/* Adds the reply to the reply linked list.
 * Note: some edits to this function need to be relayed to AddReplyFromClient. */