/*
* local_window_size
* ^ *
* | * recv_window_size
* | * * ^
* | * * |
* 0+++++++++
* | * * \
* | * * | This rage is hidden in flow control. But it must be
* v * * / kept in order to restore it when window size is enlarged.
* recv_reduction
* (+ for negative direction)
*
* recv_window_size could be negative if we decrease
* local_window_size more than recv_window_size:
*
* local_window_size
* ^ *
* | *
* | *
* 0++++++++
* | * ^ recv_window_size (negative)
* | * |
* v * *
* recv_reduction
*/
int nghttp2_adjust_local_window_size(int32_t *local_window_size_ptr,
int32_t *recv_window_size_ptr,
int32_t *recv_reduction_ptr,
int32_t *delta_ptr) {
if (*delta_ptr > 0) {
int32_t recv_reduction_delta;
int32_t delta;
int32_t new_recv_window_size =
nghttp2_max(0, *recv_window_size_ptr) - *delta_ptr;
if (new_recv_window_size >= 0) {
*recv_window_size_ptr = new_recv_window_size;
return 0;
}
delta = -new_recv_window_size;
/* The delta size is strictly more than received bytes. Increase
local_window_size by that difference |delta|. */
if (*local_window_size_ptr > NGHTTP2_MAX_WINDOW_SIZE - delta) {
return NGHTTP2_ERR_FLOW_CONTROL;
}
*local_window_size_ptr += delta;
/* If there is recv_reduction due to earlier window_size
reduction, we have to adjust it too. */
recv_reduction_delta = nghttp2_min(*recv_reduction_ptr, delta);
*recv_reduction_ptr -= recv_reduction_delta;
if (*recv_window_size_ptr < 0) {
*recv_window_size_ptr += recv_reduction_delta;
} else {
/* If *recv_window_size_ptr > 0, then those bytes are going to
be returned to the remote peer (by WINDOW_UPDATE with the
adjusted *delta_ptr), so it is effectively 0 now. We set to
*recv_reduction_delta, because caller does not take into
account it in *delta_ptr. */
*recv_window_size_ptr = recv_reduction_delta;
}
/* recv_reduction_delta must be paied from *delta_ptr, since it
was added in window size reduction (see below). */
*delta_ptr -= recv_reduction_delta;
return 0;
}
if (*local_window_size_ptr + *delta_ptr < 0 ||
*recv_window_size_ptr < INT32_MIN - *delta_ptr ||
*recv_reduction_ptr > INT32_MAX + *delta_ptr) {
return NGHTTP2_ERR_FLOW_CONTROL;
}
/* Decreasing local window size. Note that we achieve this without
noticing to the remote peer. To do this, we cut
recv_window_size by -delta. This means that we don't send
WINDOW_UPDATE for -delta bytes. */
*local_window_size_ptr += *delta_ptr;
*recv_window_size_ptr += *delta_ptr;
*recv_reduction_ptr -= *delta_ptr;
*delta_ptr = 0;
return 0;
}
int nghttp2_buf_reserve(nghttp2_buf *buf, size_t new_cap)
{
uint8_t *ptr;
size_t cap;
cap = nghttp2_buf_cap(buf);
if(cap >= new_cap) {
return 0;
}
new_cap = nghttp2_max(new_cap, cap * 2);
ptr = (uint8_t *)realloc(buf->begin, new_cap);
if(ptr == NULL) {
return NGHTTP2_ERR_NOMEM;
}
buf->pos = ptr + (buf->pos - buf->begin);
buf->last = ptr + (buf->last - buf->begin);
buf->mark = ptr + (buf->mark - buf->begin);
buf->begin = ptr;
buf->end = ptr + new_cap;
return 0;
}
void nghttp2_stream_reschedule(nghttp2_stream *stream) {
nghttp2_stream *dep_stream;
assert(stream->queued);
dep_stream = stream->dep_prev;
for (; dep_stream; stream = dep_stream, dep_stream = dep_stream->dep_prev) {
if (nghttp2_pq_size(&dep_stream->obq) == 1) {
dep_stream->descendant_last_cycle = 0;
stream->cycle = 0;
} else {
dep_stream->descendant_last_cycle =
nghttp2_max(dep_stream->descendant_last_cycle, stream->cycle);
stream->cycle =
stream_next_cycle(stream, dep_stream->descendant_last_cycle);
nghttp2_pq_remove(&dep_stream->obq, &stream->pq_entry);
nghttp2_pq_push(&dep_stream->obq, &stream->pq_entry);
}
DEBUGF(fprintf(stderr, "stream: stream=%d obq resched cycle=%ld\n",
stream->stream_id, stream->cycle));
dep_stream->last_writelen = stream->last_writelen;
}
}
int nghttp2_submit_window_update(nghttp2_session *session, uint8_t flags,
int32_t stream_id,
int32_t window_size_increment) {
int rv;
nghttp2_stream *stream = 0;
if (window_size_increment == 0) {
return 0;
}
flags = 0;
if (stream_id == 0) {
rv = nghttp2_adjust_local_window_size(
&session->local_window_size, &session->recv_window_size,
&session->recv_reduction, &window_size_increment);
if (rv != 0) {
return rv;
}
} else {
stream = nghttp2_session_get_stream(session, stream_id);
if (!stream) {
return 0;
}
rv = nghttp2_adjust_local_window_size(
&stream->local_window_size, &stream->recv_window_size,
&stream->recv_reduction, &window_size_increment);
if (rv != 0) {
return rv;
}
}
if (window_size_increment > 0) {
if (stream_id == 0) {
session->consumed_size =
nghttp2_max(0, session->consumed_size - window_size_increment);
} else {
stream->consumed_size =
nghttp2_max(0, stream->consumed_size - window_size_increment);
}
return nghttp2_session_add_window_update(session, flags, stream_id,
window_size_increment);
}
return 0;
}
int32_t nghttp2_stream_dep_distributed_effective_weight(nghttp2_stream *stream,
int32_t weight) {
if (stream->sum_norest_weight == 0) {
return stream->effective_weight;
}
weight = stream->effective_weight * weight / stream->sum_norest_weight;
return nghttp2_max(1, weight);
}
int nghttp2_buffer_reserve(nghttp2_buffer *buffer, size_t len)
{
if(len > buffer->max_capacity) {
return NGHTTP2_ERR_BUFFER_ERROR;
}
if(buffer->capacity < len) {
uint8_t *new_buf;
size_t new_cap = buffer->capacity == 0 ? 8 : buffer->capacity * 3 / 2;
new_cap = nghttp2_min(buffer->max_capacity, nghttp2_max(new_cap, len));
new_buf = realloc(buffer->buf, new_cap);
if(new_buf == NULL) {
return NGHTTP2_ERR_NOMEM;
}
buffer->buf = new_buf;
buffer->capacity = new_cap;
}
return 0;
}
int32_t nghttp2_stream_dep_distributed_weight(nghttp2_stream *stream,
int32_t weight) {
weight = stream->weight * weight / stream->sum_dep_weight;
return nghttp2_max(1, weight);
}
