自学教程：C++ H2O_STRUCT_FROM_MEMBER函数代码示例

static h2o_memcached_req_t *pop_inflight(struct st_h2o_memcached_conn_t *conn, uint32_t serial){    h2o_memcached_req_t *req;    pthread_mutex_lock(&conn->mutex);    if (conn->yrmcds.text_mode) {        /* in text mode, responses are returned in order (and we may receive responses for commands other than GET) */        if (!h2o_linklist_is_empty(&conn->inflight)) {            req = H2O_STRUCT_FROM_MEMBER(h2o_memcached_req_t, inflight, conn->inflight.next);            assert(req->type == REQ_TYPE_GET);            if (req->data.get.serial == serial)                goto Found;        }    } else {        /* in binary mode, responses are received out-of-order (and we would only recieve responses for GET) */        h2o_linklist_t *node;        for (node = conn->inflight.next; node != &conn->inflight; node = node->next) {            req = H2O_STRUCT_FROM_MEMBER(h2o_memcached_req_t, inflight, node);            assert(req->type == REQ_TYPE_GET);            if (req->data.get.serial == serial)                goto Found;        }    }    /* not found */    pthread_mutex_unlock(&conn->mutex);    return NULL;Found:    h2o_linklist_unlink(&req->inflight);    pthread_mutex_unlock(&conn->mutex);    return req;}

static h2o_http2_scheduler_queue_node_t *queue_pop(h2o_http2_scheduler_queue_t *queue){    if (!h2o_linklist_is_empty(&queue->anchor257)) {        h2o_http2_scheduler_queue_node_t *node =            H2O_STRUCT_FROM_MEMBER(h2o_http2_scheduler_queue_node_t, _link, queue->anchor257.next);        h2o_linklist_unlink(&node->_link);        return node;    }    while (queue->bits != 0) {        int zeroes = __builtin_clzll(queue->bits);        queue->bits <<= zeroes;        queue->offset = (queue->offset + zeroes) % (sizeof(queue->anchors) / sizeof(queue->anchors[0]));        if (!h2o_linklist_is_empty(queue->anchors + queue->offset)) {            h2o_http2_scheduler_queue_node_t *node =                H2O_STRUCT_FROM_MEMBER(h2o_http2_scheduler_queue_node_t, _link, queue->anchors[queue->offset].next);            h2o_linklist_unlink(&node->_link);            if (h2o_linklist_is_empty(queue->anchors + queue->offset))                queue->bits &= (1ULL << (sizeof(queue->bits) * 8 - 1)) - 1;            return node;        }        queue->bits &= (1ULL << (sizeof(queue->bits) * 8 - 1)) - 1;    }    return NULL;}

h2o_filecache_ref_t *h2o_filecache_open_file(h2o_filecache_t *cache, const char *path, int oflag){    khiter_t iter = kh_get(opencache_set, cache->hash, path);    h2o_filecache_ref_t *ref;    int dummy;    /* lookup cache, and return the one if found */    if (iter != kh_end(cache->hash)) {        ref = H2O_STRUCT_FROM_MEMBER(h2o_filecache_ref_t, _path, kh_key(cache->hash, iter));        ++ref->_refcnt;        goto Exit;    }    /* create a new cache entry */    ref = h2o_mem_alloc(offsetof(h2o_filecache_ref_t, _path) + strlen(path) + 1);    ref->_refcnt = 1;    ref->_lru = (h2o_linklist_t){NULL};    strcpy(ref->_path, path);    /* if cache is used, then... */    if (cache->capacity != 0) {        /* purge one entry from LRU if cache is full */        if (kh_size(cache->hash) == cache->capacity) {            h2o_filecache_ref_t *purge_ref = H2O_STRUCT_FROM_MEMBER(h2o_filecache_ref_t, _lru, cache->lru.prev);            khiter_t purge_iter = kh_get(opencache_set, cache->hash, purge_ref->_path);            assert(purge_iter != kh_end(cache->hash));            release_from_cache(cache, purge_iter);        }        /* assign the new entry */        ++ref->_refcnt;        kh_put(opencache_set, cache->hash, ref->_path, &dummy);        h2o_linklist_insert(cache->lru.next, &ref->_lru);    }    /* open the file, or memoize the error */    if ((ref->fd = open(path, oflag)) != -1 && fstat(ref->fd, &ref->st) == 0) {        ref->_last_modified.str[0] = '/0';        ref->_etag.len = 0;    } else {        ref->open_err = errno;        if (ref->fd != -1) {            close(ref->fd);            ref->fd = -1;        }    }Exit:    /* if the cache entry retains an error, return it instead of the reference */    if (ref->fd == -1) {        errno = ref->open_err;        h2o_filecache_close_file(ref);        ref = NULL;    }    return ref;}

static void graceful_shutdown_resend_goaway(h2o_timeout_entry_t *entry){    h2o_context_t *ctx = H2O_STRUCT_FROM_MEMBER(h2o_context_t, http2._graceful_shutdown_timeout, entry);    h2o_linklist_t *node;    for (node = ctx->http2._conns.next; node != &ctx->http2._conns; node = node->next) {        h2o_http2_conn_t *conn = H2O_STRUCT_FROM_MEMBER(h2o_http2_conn_t, _conns, node);        if (conn->state < H2O_HTTP2_CONN_STATE_HALF_CLOSED)            enqueue_goaway(conn, H2O_HTTP2_ERROR_NONE, (h2o_iovec_t){});    }}

static int compare_fortunes(const list_t *x, const list_t *y){	const fortune_t * const f1 = H2O_STRUCT_FROM_MEMBER(fortune_t, l, x);	const fortune_t * const f2 = H2O_STRUCT_FROM_MEMBER(fortune_t, l, y);	const size_t sz = MIN(f1->message.len, f2->message.len);	int ret = memcmp(f1->message.base, f2->message.base, sz);	if (!ret)		ret = f1->message.len < f2->message.len ? -1 : f1->message.len > f2->message.len;	return ret;}

static void complete_fortunes(struct st_h2o_generator_t *self, h2o_req_t *req){	fortune_ctx_t * const fortune_ctx = H2O_STRUCT_FROM_MEMBER(fortune_ctx_t, generator, self);	iovec_list_t * const iovec_list = H2O_STRUCT_FROM_MEMBER(iovec_list_t,	                                                         l,	                                                         fortune_ctx->iovec_list);	fortune_ctx->iovec_list = iovec_list->l.next;	const h2o_send_state_t state = fortune_ctx->iovec_list ?	                               H2O_SEND_STATE_IN_PROGRESS :	                               H2O_SEND_STATE_FINAL;	h2o_send(req, iovec_list->iov, iovec_list->iovcnt, state);}

static void on_idle_timeout(h2o_timeout_entry_t *entry){    h2o_http2_conn_t *conn = H2O_STRUCT_FROM_MEMBER(h2o_http2_conn_t, _timeout_entry, entry);    enqueue_goaway(conn, H2O_HTTP2_ERROR_NONE, h2o_iovec_init(H2O_STRLIT("idle timeout")));    close_connection(conn);}

static int proceed(h2o_http2_scheduler_node_t *node, h2o_http2_scheduler_run_cb cb, void *cb_arg){Redo:    if (node->_queue == NULL)        return 0;    h2o_http2_scheduler_queue_node_t *drr_node = queue_pop(node->_queue);    if (drr_node == NULL)        return 0;    h2o_http2_scheduler_openref_t *ref = H2O_STRUCT_FROM_MEMBER(h2o_http2_scheduler_openref_t, _queue_node, drr_node);    if (!ref->_self_is_active) {        /* run the children (manually-unrolled tail recursion) */        queue_set(node->_queue, &ref->_queue_node, ref->weight);        node = &ref->node;        goto Redo;    }    assert(ref->_active_cnt != 0);    /* call the callbacks */    int still_is_active, bail_out = cb(ref, &still_is_active, cb_arg);    if (still_is_active) {        queue_set(node->_queue, &ref->_queue_node, ref->weight);    } else {        ref->_self_is_active = 0;        if (--ref->_active_cnt != 0) {            queue_set(node->_queue, &ref->_queue_node, ref->weight);        } else if (ref->node._parent != NULL) {            decr_active_cnt(ref->node._parent);        }    }    return bail_out;}

static void accept_connection(h2o_socket_t *listener, const char *err){	if (err)		ERROR(err);	else {		thread_context_t * const ctx = H2O_STRUCT_FROM_MEMBER(thread_context_t,		                                                      event_loop,		                                                      listener->data);		if (!ctx->global_data->shutdown) {			size_t accepted = ctx->config->max_accept;			do {				h2o_socket_t * const sock = h2o_evloop_socket_accept(listener);				if (!sock)					break;				ctx->event_loop.conn_num++;				sock->on_close.cb = on_close_connection;				sock->on_close.data = &ctx->event_loop.conn_num;				h2o_accept(&ctx->event_loop.h2o_accept_ctx, sock);			} while (--accepted > 0);		}	}}

static void shutdown_server(h2o_socket_t *listener, const char *err){	if (err)		ERROR(err);	else {		thread_context_t * const ctx = H2O_STRUCT_FROM_MEMBER(thread_context_t,		                                                      event_loop,		                                                      listener->data);		ctx->global_data->shutdown = true;		// Close the listening sockets immediately, so that if another instance		// of the application is started before the current one exits (e.g. when		// doing an update), it will accept all incoming connections.		if (ctx->event_loop.h2o_https_socket) {			h2o_socket_read_stop(ctx->event_loop.h2o_https_socket);			h2o_socket_close(ctx->event_loop.h2o_https_socket);			ctx->event_loop.h2o_https_socket = NULL;		}		if (ctx->event_loop.h2o_socket) {			h2o_socket_read_stop(ctx->event_loop.h2o_socket);			h2o_socket_close(ctx->event_loop.h2o_socket);			ctx->event_loop.h2o_socket = NULL;		}		for (size_t i = ctx->config->thread_num - 1; i > 0; i--)			h2o_multithread_send_message(&ctx->global_thread_data[i].h2o_receiver, NULL);	}}

static uintmax_t on_fortune_section(mustache_api_t *api,                                    void *userdata,                                    mustache_token_section_t *token){	fortune_ctx_t * const fortune_ctx = userdata;	uintmax_t ret = 1;	if (fortune_ctx->num_result) {		assert(fortune_ctx->result);		const list_t *iter = fortune_ctx->result;		do {			fortune_ctx->fortune_iter = H2O_STRUCT_FROM_MEMBER(fortune_t, l, iter);			iter = iter->next;			if (!mustache_render(api, fortune_ctx, token->section)) {				ret = 0;				break;			}		} while (iter);	}	return ret;}

void finalostream_send(h2o_ostream_t *self, h2o_req_t *req, h2o_iovec_t *bufs, size_t bufcnt, int is_final){    h2o_http2_stream_t *stream = H2O_STRUCT_FROM_MEMBER(h2o_http2_stream_t, _ostr_final, self);    h2o_http2_conn_t *conn = (h2o_http2_conn_t*)req->conn;    assert(stream->_data.size == 0);    /* send headers */    switch (stream->state) {    case H2O_HTTP2_STREAM_STATE_SEND_HEADERS:        send_headers(conn, stream);        /* fallthru */    case H2O_HTTP2_STREAM_STATE_SEND_BODY:        if (is_final)            stream->state = H2O_HTTP2_STREAM_STATE_END_STREAM;        break;    case H2O_HTTP2_STREAM_STATE_END_STREAM:        /* might get set by h2o_http2_stream_reset */        return;    default:        assert(!"cannot be in a receiving state");    }    /* save the contents in queue */    if (bufcnt != 0) {        h2o_vector_reserve(&req->pool, (h2o_vector_t*)&stream->_data, sizeof(h2o_iovec_t), bufcnt);        memcpy(stream->_data.entries, bufs, sizeof(h2o_iovec_t) * bufcnt);        stream->_data.size = bufcnt;    }    h2o_http2_conn_register_for_proceed_callback(conn, stream);}

static void initiate_graceful_shutdown(h2o_context_t *ctx){    /* draft-16 6.8     * A server that is attempting to gracefully shut down a connection SHOULD send an initial GOAWAY frame with the last stream     * identifier set to 231-1 and a NO_ERROR code. This signals to the client that a shutdown is imminent and that no further     * requests can be initiated. After waiting at least one round trip time, the server can send another GOAWAY frame with an     * updated last stream identifier. This ensures that a connection can be cleanly shut down without losing requests.     */    h2o_linklist_t *node;    /* only doit once */    if (ctx->http2._graceful_shutdown_timeout.cb != NULL)        return;    ctx->http2._graceful_shutdown_timeout.cb = graceful_shutdown_resend_goaway;    for (node = ctx->http2._conns.next; node != &ctx->http2._conns; node = node->next) {        h2o_http2_conn_t *conn = H2O_STRUCT_FROM_MEMBER(h2o_http2_conn_t, _conns, node);        if (conn->state < H2O_HTTP2_CONN_STATE_HALF_CLOSED) {            h2o_http2_encode_goaway_frame(&conn->_write.buf, INT32_MAX, H2O_HTTP2_ERROR_NONE,                                          (h2o_iovec_t){H2O_STRLIT("graceful shutdown")});            h2o_http2_conn_request_write(conn);        }    }    h2o_timeout_link(ctx->loop, &ctx->one_sec_timeout, &ctx->http2._graceful_shutdown_timeout);}

static void finalostream_start_pull(h2o_ostream_t *_self, h2o_ostream_pull_cb cb){    h2o_http1_conn_t *conn = H2O_STRUCT_FROM_MEMBER(h2o_http1_conn_t, _ostr_final.super, _self);    const char *connection = conn->req.http1_is_persistent ? "keep-alive" : "close";    size_t bufsz, headers_len;    assert(conn->req._ostr_top == &conn->_ostr_final.super);    assert(! conn->_ostr_final.sent_headers);    /* register the pull callback */    conn->_ostr_final.pull.cb = cb;    /* setup the buffer */    bufsz = flatten_headers_estimate_size(&conn->req, conn->super.ctx->globalconf->server_name.len + strlen(connection));    if (bufsz < MAX_PULL_BUF_SZ) {        if (MAX_PULL_BUF_SZ - bufsz < conn->req.res.content_length) {            bufsz = MAX_PULL_BUF_SZ;        } else {            bufsz += conn->req.res.content_length;        }    }    conn->_ostr_final.pull.buf = h2o_mem_alloc_pool(&conn->req.pool, bufsz);    /* fill-in the header */    headers_len = flatten_headers(conn->_ostr_final.pull.buf, &conn->req, connection);    conn->_ostr_final.sent_headers = 1;    proceed_pull(conn, headers_len);}

static void purge(h2o_cache_t *cache, uint64_t now){    /* by cache size */    while (cache->capacity < cache->size) {        h2o_cache_ref_t *last;        assert(!h2o_linklist_is_empty(&cache->lru));        last = H2O_STRUCT_FROM_MEMBER(h2o_cache_ref_t, _lru_link, cache->lru.next);        erase_ref(cache, kh_get(cache, cache->table, last), 0);    }    /* by TTL */    while (!h2o_linklist_is_empty(&cache->age)) {        h2o_cache_ref_t *oldest = H2O_STRUCT_FROM_MEMBER(h2o_cache_ref_t, _age_link, cache->age.next);        if (get_timeleft(cache, oldest, now) >= 0)            break;        erase_ref(cache, kh_get(cache, cache->table, oldest), 0);    }}

static void reqread_on_timeout(h2o_timeout_entry_t *entry){    h2o_http1_conn_t *conn = H2O_STRUCT_FROM_MEMBER(h2o_http1_conn_t, _timeout_entry, entry);    /* TODO log */    conn->req.http1_is_persistent = 0;    close_connection(conn);}

uint64_t h2o_timeout_get_wake_at(h2o_linklist_t *timeouts){    h2o_linklist_t *node;    uint64_t wake_at = UINT64_MAX;    /* change wake_at to the minimum value of the timeouts */    for (node = timeouts->next; node != timeouts; node = node->next) {        h2o_timeout_t *timeout = H2O_STRUCT_FROM_MEMBER(h2o_timeout_t, _link, node);        if (!h2o_linklist_is_empty(&timeout->_entries)) {            h2o_timeout_entry_t *entry = H2O_STRUCT_FROM_MEMBER(h2o_timeout_entry_t, _link, timeout->_entries.next);            uint64_t entry_wake_at = entry->registered_at + timeout->timeout;            if (entry_wake_at < wake_at)                wake_at = entry_wake_at;        }    }    return wake_at;}

static void process_messages(h2o_multithread_receiver_t *receiver, h2o_linklist_t *messages){	IGNORE_FUNCTION_PARAMETER(messages);	thread_context_t * const ctx = H2O_STRUCT_FROM_MEMBER(thread_context_t,	                                                      event_loop.h2o_receiver,	                                                      receiver);	h2o_socket_read_stop(ctx->event_loop.h2o_socket);}

void h2o_configurator__dispose_configurators(h2o_globalconf_t *conf){    while (!h2o_linklist_is_empty(&conf->configurators)) {        h2o_configurator_t *c = H2O_STRUCT_FROM_MEMBER(h2o_configurator_t, _link, conf->configurators.next);        h2o_linklist_unlink(&c->_link);        if (c->dispose != NULL)            c->dispose(c);        destroy_configurator(c);    }}

static int complete_configurators(h2o_linklist_t *configurators, void *config){    h2o_linklist_t *node;    for (node = configurators->next; node != configurators; node = node->next) {        h2o_configurator_t *configurator = H2O_STRUCT_FROM_MEMBER(h2o_configurator_t, _link, node);        if (configurator->on_complete != NULL)            if (configurator->on_complete(configurator, config) != 0)                return -1;    }    return 0;}

static void accept_http_connection(h2o_socket_t *listener, const char *err){	// Assume that err is most often NULL.	thread_context_t * const ctx = H2O_STRUCT_FROM_MEMBER(thread_context_t,	                                                      event_loop,	                                                      listener->data);	SSL_CTX * const ssl_ctx = ctx->event_loop.h2o_accept_ctx.ssl_ctx;	ctx->event_loop.h2o_accept_ctx.ssl_ctx = NULL;	accept_connection(listener, err);	ctx->event_loop.h2o_accept_ctx.ssl_ctx = ssl_ctx;}

h2o_configurator_t *h2o_config_get_configurator(h2o_linklist_t *anchor, const char *cmd){    h2o_linklist_t *node;    for (node = anchor->next; node != anchor; node = node->next) {        h2o_configurator_t *configurator = H2O_STRUCT_FROM_MEMBER(h2o_configurator_t, _link, node);        if (strcmp(configurator->cmd, cmd) == 0)            return configurator;    }    return NULL;}

static inline void release_from_cache(h2o_filecache_t *cache, khiter_t iter){    const char *path = kh_key(cache->hash, iter);    h2o_filecache_ref_t *ref = H2O_STRUCT_FROM_MEMBER(h2o_filecache_ref_t, _path, path);    /* detach from list */    kh_del(opencache_set, cache->hash, iter);    h2o_linklist_unlink(&ref->_lru);    /* and close */    h2o_filecache_close_file(ref);}

void h2o_http2_scheduler_close(h2o_http2_scheduler_openref_t *ref){    assert(h2o_http2_scheduler_is_open(ref));    /* move dependents to parent */    if (!h2o_linklist_is_empty(&ref->node._all_refs)) {        /* proportionally distribute the weight to the children (draft-16 5.3.4) */        uint32_t total_weight = 0, factor;        h2o_linklist_t *link;        for (link = ref->node._all_refs.next; link != &ref->node._all_refs; link = link->next) {            h2o_http2_scheduler_openref_t *child_ref = H2O_STRUCT_FROM_MEMBER(h2o_http2_scheduler_openref_t, _all_link, link);            total_weight += child_ref->weight;        }        assert(total_weight != 0);        factor = ((uint32_t)ref->weight * 65536 + total_weight / 2) / total_weight;        do {            h2o_http2_scheduler_openref_t *child_ref =                H2O_STRUCT_FROM_MEMBER(h2o_http2_scheduler_openref_t, _all_link, ref->node._all_refs.next);            uint16_t weight = (child_ref->weight * factor / 32768 + 1) / 2;            if (weight < 1)                weight = 1;            else if (weight > 256)                weight = 256;            h2o_http2_scheduler_rebind(child_ref, ref->node._parent, weight, 0);        } while (!h2o_linklist_is_empty(&ref->node._all_refs));    }    free(ref->node._queue);    ref->node._queue = NULL;    /* detach self */    h2o_linklist_unlink(&ref->_all_link);    if (ref->_self_is_active) {        assert(ref->_active_cnt == 1);        queue_unset(&ref->_queue_node);        decr_active_cnt(ref->node._parent);    } else {        assert(ref->_active_cnt == 0);    }}

static void run_pending_requests(h2o_http2_conn_t *conn){    while (!h2o_linklist_is_empty(&conn->_pending_reqs) && can_run_requests(conn)) {        /* fetch and detach a pending stream */        h2o_http2_stream_t *stream = H2O_STRUCT_FROM_MEMBER(h2o_http2_stream_t, _refs.link, conn->_pending_reqs.next);        h2o_linklist_unlink(&stream->_refs.link);        /* handle it */        h2o_http2_stream_set_state(conn, stream, H2O_HTTP2_STREAM_STATE_SEND_HEADERS);        if (!h2o_http2_stream_is_push(stream->stream_id) && conn->pull_stream_ids.max_processed < stream->stream_id)            conn->pull_stream_ids.max_processed = stream->stream_id;        h2o_process_request(&stream->req);    }}

void h2o_config_dispose(h2o_global_configuration_t *config){    while (! h2o_linklist_is_empty(&config->virtual_hosts)) {        h2o_host_configuration_t *host_config = H2O_STRUCT_FROM_MEMBER(h2o_host_configuration_t, _link, config->virtual_hosts.next);        h2o_linklist_unlink(&host_config->_link);        dispose_host_config(host_config);        free(host_config);    }    dispose_host_config(&config->default_host);    DESTROY_LIST(h2o_configurator_t, config->global_configurators);    DESTROY_LIST(h2o_configurator_t, config->host_configurators);}

int h2o_config_on_context_create(h2o_global_configuration_t *config, h2o_context_t *ctx){    h2o_linklist_t *node;    for (node = config->global_configurators.next; node != &config->global_configurators; node = node->next) {        h2o_configurator_t *configurator = H2O_STRUCT_FROM_MEMBER(h2o_configurator_t, _link, node);        if (configurator->on_context_create != NULL)            if (configurator->on_context_create(configurator, ctx) != 0)                return -1;    }    return 0;}

static void convert_to_exclusive(h2o_http2_scheduler_node_t *parent, h2o_http2_scheduler_openref_t *added){    while (!h2o_linklist_is_empty(&parent->_all_refs)) {        h2o_http2_scheduler_openref_t *child_ref =            H2O_STRUCT_FROM_MEMBER(h2o_http2_scheduler_openref_t, _all_link, parent->_all_refs.next);        if (child_ref == added) {            /* precond: the added node should exist as the last item within parent */            assert(parent->_all_refs.prev == &added->_all_link);            break;        }        h2o_http2_scheduler_rebind(child_ref, &added->node, h2o_http2_scheduler_get_weight(child_ref), 0);    }}

void h2o_cache_clear(h2o_cache_t *cache){    lock_cache(cache);    while (!h2o_linklist_is_empty(&cache->lru)) {        h2o_cache_ref_t *ref = H2O_STRUCT_FROM_MEMBER(h2o_cache_ref_t, _lru_link, cache->lru.next);        erase_ref(cache, kh_get(cache, cache->table, ref), 0);    }    assert(h2o_linklist_is_linked(&cache->age));    assert(kh_size(cache->table) == 0);    assert(cache->size == 0);    unlock_cache(cache);}