static ngx_int_t
ngx_http_replace_output(ngx_http_request_t *r, ngx_http_replace_ctx_t *ctx)
{
ngx_int_t rc;
ngx_buf_t *b;
ngx_chain_t *cl;
#if (DDEBUG)
b = NULL;
for (cl = ctx->out; cl; cl = cl->next) {
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"replace out: %p %p", cl->buf, cl->buf->pos);
if (cl->buf == b) {
ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0,
"the same buf was used in sub");
ngx_debug_point();
return NGX_ERROR;
}
b = cl->buf;
}
/* ngx_http_replace_dump_chain("ctx->out", &ctx->out, ctx->last_out); */
#endif
rc = ngx_http_next_body_filter(r, ctx->out);
/* we are essentially duplicating the logic of
* ngx_chain_update_chains below,
* with our own optimizations */
if (ctx->busy == NULL) {
ctx->busy = ctx->out;
} else {
for (cl = ctx->busy; cl->next; cl = cl->next) { /* void */ }
cl->next = ctx->out;
}
ctx->out = NULL;
ctx->last_out = &ctx->out;
while (ctx->busy) {
cl = ctx->busy;
b = cl->buf;
if (ngx_buf_size(b) != 0) {
break;
}
if (cl->buf->tag != (ngx_buf_tag_t) &ngx_http_replace_filter_module) {
ctx->busy = cl->next;
ngx_free_chain(r->pool, cl);
continue;
}
if (b->shadow) {
b->shadow->pos = b->shadow->last;
b->shadow->file_pos = b->shadow->file_last;
}
ctx->busy = cl->next;
if (ngx_buf_special(b)) {
/* collect special bufs to ctx->special, which may still be busy */
cl->next = NULL;
*ctx->last_special = cl;
ctx->last_special = &cl->next;
} else {
/* add ctx->special to ctx->free because they cannot be busy at
* this point */
*ctx->last_special = ctx->free;
ctx->free = ctx->special;
ctx->special = NULL;
ctx->last_special = &ctx->special;
#if 0
/* free the temporary buf's data block if it is big enough */
if (b->temporary
&& b->start != NULL
&& b->end - b->start > (ssize_t) r->pool->max)
{
ngx_pfree(r->pool, b->start);
}
#endif
/* add the data buf itself to the free buf chain */
cl->next = ctx->free;
ctx->free = cl;
}
}
if (ctx->in || ctx->buf) {
r->buffered |= NGX_HTTP_SUB_BUFFERED;
} else {
r->buffered &= ~NGX_HTTP_SUB_BUFFERED;
}
return rc;
}
ngx_int_t
ngx_http_write_filter(ngx_http_request_t *r, ngx_chain_t *in)
{
off_t size, sent, nsent, limit;
ngx_uint_t last, flush, sync;
ngx_msec_t delay;
ngx_chain_t *cl, *ln, **ll, *chain;
ngx_connection_t *c;
ngx_http_core_loc_conf_t *clcf;
c = r->connection;
if (c->error) {
return NGX_ERROR;
}
size = 0;
flush = 0;
sync = 0;
last = 0;
ll = &r->out;
/* find the size, the flush point and the last link of the saved chain */
for (cl = r->out; cl; cl = cl->next) {
ll = &cl->next;
ngx_log_debug7(NGX_LOG_DEBUG_EVENT, c->log, 0,
"write old buf t:%d f:%d %p, pos %p, size: %z "
"file: %O, size: %O",
cl->buf->temporary, cl->buf->in_file,
cl->buf->start, cl->buf->pos,
cl->buf->last - cl->buf->pos,
cl->buf->file_pos,
cl->buf->file_last - cl->buf->file_pos);
#if 1
if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) {
ngx_log_error(NGX_LOG_ALERT, c->log, 0,
"zero size buf in writer "
"t:%d r:%d f:%d %p %p-%p %p %O-%O",
cl->buf->temporary,
cl->buf->recycled,
cl->buf->in_file,
cl->buf->start,
cl->buf->pos,
cl->buf->last,
cl->buf->file,
cl->buf->file_pos,
cl->buf->file_last);
ngx_debug_point();
return NGX_ERROR;
}
#endif
size += ngx_buf_size(cl->buf);
if (cl->buf->flush || cl->buf->recycled) {
flush = 1;
}
if (cl->buf->sync) {
sync = 1;
}
if (cl->buf->last_buf) {
last = 1;
}
}
/* add the new chain to the existent one */
for (ln = in; ln; ln = ln->next) {
cl = ngx_alloc_chain_link(r->pool);
if (cl == NULL) {
return NGX_ERROR;
}
cl->buf = ln->buf;
*ll = cl;
ll = &cl->next;
ngx_log_debug7(NGX_LOG_DEBUG_EVENT, c->log, 0,
"write new buf t:%d f:%d %p, pos %p, size: %z "
"file: %O, size: %O",
cl->buf->temporary, cl->buf->in_file,
cl->buf->start, cl->buf->pos,
cl->buf->last - cl->buf->pos,
cl->buf->file_pos,
cl->buf->file_last - cl->buf->file_pos);
#if 1
if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) {
ngx_log_error(NGX_LOG_ALERT, c->log, 0,
"zero size buf in writer "
"t:%d r:%d f:%d %p %p-%p %p %O-%O",
cl->buf->temporary,
cl->buf->recycled,
cl->buf->in_file,
cl->buf->start,
cl->buf->pos,
cl->buf->last,
cl->buf->file,
cl->buf->file_pos,
cl->buf->file_last);
ngx_debug_point();
return NGX_ERROR;
}
#endif
size += ngx_buf_size(cl->buf);
if (cl->buf->flush || cl->buf->recycled) {
flush = 1;
}
if (cl->buf->sync) {
sync = 1;
}
if (cl->buf->last_buf) {
last = 1;
}
}
*ll = NULL;
ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0,
"http write filter: l:%d f:%d s:%O", last, flush, size);
clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
/*
* avoid the output if there are no last buf, no flush point,
* there are the incoming bufs and the size of all bufs
* is smaller than "postpone_output" directive
*/
if (!last && !flush && in && size < (off_t) clcf->postpone_output) {
return NGX_OK;
}
if (c->write->delayed) {
c->buffered |= NGX_HTTP_WRITE_BUFFERED;
return NGX_AGAIN;
}
if (size == 0
&& !(c->buffered & NGX_LOWLEVEL_BUFFERED)
&& !(last && c->need_last_buf))
{
if (last || flush || sync) {
for (cl = r->out; cl; /* void */) {
ln = cl;
cl = cl->next;
ngx_free_chain(r->pool, ln);
}
r->out = NULL;
c->buffered &= ~NGX_HTTP_WRITE_BUFFERED;
return NGX_OK;
}
ngx_log_error(NGX_LOG_ALERT, c->log, 0,
"the http output chain is empty");
ngx_debug_point();
return NGX_ERROR;
}
if (r->limit_rate) {
if (r->limit_rate_after == 0) {
r->limit_rate_after = clcf->limit_rate_after;
}
limit = (off_t) r->limit_rate * (ngx_time() - r->start_sec + 1)
- (c->sent - r->limit_rate_after);
if (limit <= 0) {
c->write->delayed = 1;
delay = (ngx_msec_t) (- limit * 1000 / r->limit_rate + 1);
ngx_add_timer(c->write, delay);
c->buffered |= NGX_HTTP_WRITE_BUFFERED;
return NGX_AGAIN;
}
if (clcf->sendfile_max_chunk
&& (off_t) clcf->sendfile_max_chunk < limit)
{
limit = clcf->sendfile_max_chunk;
}
} else {
limit = clcf->sendfile_max_chunk;
}
sent = c->sent;
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
"http write filter limit %O", limit);
chain = c->send_chain(c, r->out, limit);
if (ngx_http_log_flow && ngx_http_log_flow(r) == NGX_ERROR) {
return NGX_ERROR;
}
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
"http write filter %p", chain);
if (chain == NGX_CHAIN_ERROR) {
c->error = 1;
return NGX_ERROR;
}
if (r->limit_rate) {
nsent = c->sent;
if (r->limit_rate_after) {
sent -= r->limit_rate_after;
if (sent < 0) {
sent = 0;
}
nsent -= r->limit_rate_after;
if (nsent < 0) {
nsent = 0;
}
}
delay = (ngx_msec_t) ((nsent - sent) * 1000 / r->limit_rate);
if (delay > 0) {
limit = 0;
c->write->delayed = 1;
ngx_add_timer(c->write, delay);
}
}
if (limit
&& c->write->ready
&& c->sent - sent >= limit - (off_t) (2 * ngx_pagesize))
{
c->write->delayed = 1;
ngx_add_timer(c->write, 1);
}
for (cl = r->out; cl && cl != chain; /* void */) {
ln = cl;
cl = cl->next;
ngx_free_chain(r->pool, ln);
}
r->out = chain;
if (chain) {
c->buffered |= NGX_HTTP_WRITE_BUFFERED;
return NGX_AGAIN;
}
c->buffered &= ~NGX_HTTP_WRITE_BUFFERED;
if ((c->buffered & NGX_LOWLEVEL_BUFFERED) && r->postponed == NULL) {
return NGX_AGAIN;
}
return NGX_OK;
}
ngx_int_t
ngx_output_chain(ngx_output_chain_ctx_t *ctx, ngx_chain_t *in)
{
off_t bsize;
ngx_int_t rc, last;
ngx_chain_t *cl, *out, **last_out;
if (ctx->in == NULL && ctx->busy == NULL) {
/*
* the short path for the case when the ctx->in and ctx->busy chains
* are empty, the incoming chain is empty too or has the single buf
* that does not require the copy
*/
if (in == NULL) {
return ctx->output_filter(ctx->filter_ctx, in);
}
if (in->next == NULL
#if (NGX_SENDFILE_LIMIT)
&& !(in->buf->in_file && in->buf->file_last > NGX_SENDFILE_LIMIT)
#endif
&& ngx_output_chain_as_is(ctx, in->buf))
{
return ctx->output_filter(ctx->filter_ctx, in);
}
}
/* add the incoming buf to the chain ctx->in */
if (in) {
if (ngx_output_chain_add_copy(ctx->pool, &ctx->in, in) == NGX_ERROR) {
return NGX_ERROR;
}
}
#if (NGX_HAVE_FILE_AIO)
if (ctx->aio) {
return NGX_AGAIN;
}
#endif
out = NULL;
last_out = &out;
last = NGX_NONE;
for ( ;; ) {
while (ctx->in) {
/*
* cycle while there are the ctx->in bufs
* and there are the free output bufs to copy in
*/
bsize = ngx_buf_size(ctx->in->buf);
if (bsize == 0 && !ngx_buf_special(ctx->in->buf)) {
ngx_log_error(NGX_LOG_ALERT, ctx->pool->log, 0,
"zero size buf in output "
"t:%d r:%d f:%d %p %p-%p %p %O-%O",
ctx->in->buf->temporary,
ctx->in->buf->recycled,
ctx->in->buf->in_file,
ctx->in->buf->start,
ctx->in->buf->pos,
ctx->in->buf->last,
ctx->in->buf->file,
ctx->in->buf->file_pos,
ctx->in->buf->file_last);
ngx_debug_point();
ctx->in = ctx->in->next;
continue;
}
if (ngx_output_chain_as_is(ctx, ctx->in->buf)) {
/* move the chain link to the output chain */
cl = ctx->in;
ctx->in = cl->next;
*last_out = cl;
last_out = &cl->next;
cl->next = NULL;
continue;
}
if (ctx->buf == NULL) {
rc = ngx_output_chain_align_file_buf(ctx, bsize);
if (rc == NGX_ERROR) {
return NGX_ERROR;
}
if (rc != NGX_OK) {
if (ctx->free) {
/* get the free buf */
cl = ctx->free;
ctx->buf = cl->buf;
ctx->free = cl->next;
ngx_free_chain(ctx->pool, cl);
} else if (out || ctx->allocated == ctx->bufs.num) {
break;
} else if (ngx_output_chain_get_buf(ctx, bsize) != NGX_OK) {
return NGX_ERROR;
}
}
}
rc = ngx_output_chain_copy_buf(ctx);
if (rc == NGX_ERROR) {
return rc;
}
if (rc == NGX_AGAIN) {
if (out) {
break;
}
return rc;
}
/* delete the completed buf from the ctx->in chain */
if (ngx_buf_size(ctx->in->buf) == 0) {
ctx->in = ctx->in->next;
}
cl = ngx_alloc_chain_link(ctx->pool);
if (cl == NULL) {
return NGX_ERROR;
}
cl->buf = ctx->buf;
cl->next = NULL;
*last_out = cl;
last_out = &cl->next;
ctx->buf = NULL;
}
if (out == NULL && last != NGX_NONE) {
if (ctx->in) {
return NGX_AGAIN;
}
return last;
}
last = ctx->output_filter(ctx->filter_ctx, out);
if (last == NGX_ERROR || last == NGX_DONE) {
return last;
}
ngx_chain_update_chains(&ctx->free, &ctx->busy, &out, ctx->tag);
last_out = &out;
}
}
static ngx_int_t
ngx_event_pipe_read_upstream(ngx_event_pipe_t *p)
{
ssize_t n, size;
ngx_int_t rc;
ngx_buf_t *b;
ngx_chain_t *chain, *cl, *ln;
if (p->upstream_eof || p->upstream_error || p->upstream_done) {
return NGX_OK;
}
ngx_log_debug1(NGX_LOG_DEBUG_EVENT, p->log, 0,
"pipe read upstream: %d", p->upstream->read->ready);
for ( ;; ) {
if (p->upstream_eof || p->upstream_error || p->upstream_done) {
break;
}
if (p->preread_bufs == NULL && !p->upstream->read->ready) {
break;
}
if (p->preread_bufs) {
/* use the pre-read bufs if they exist */
chain = p->preread_bufs;
p->preread_bufs = NULL;
n = p->preread_size;
ngx_log_debug1(NGX_LOG_DEBUG_EVENT, p->log, 0,
"pipe preread: %z", n);
if (n) {
p->read = 1;
}
} else {
#if (NGX_HAVE_KQUEUE)
/*
* kqueue notifies about the end of file or a pending error.
* This test allows not to allocate a buf on these conditions
* and not to call c->recv_chain().
*/
if (p->upstream->read->available == 0
&& p->upstream->read->pending_eof)
{
p->upstream->read->ready = 0;
p->upstream->read->eof = 0;
p->upstream_eof = 1;
p->read = 1;
if (p->upstream->read->kq_errno) {
p->upstream->read->error = 1;
p->upstream_error = 1;
p->upstream_eof = 0;
ngx_log_error(NGX_LOG_ERR, p->log,
p->upstream->read->kq_errno,
"kevent() reported that upstream "
"closed connection");
}
break;
}
#endif
if (p->free_raw_bufs) {
/* use the free bufs if they exist */
chain = p->free_raw_bufs;
if (p->single_buf) {
p->free_raw_bufs = p->free_raw_bufs->next;
chain->next = NULL;
} else {
p->free_raw_bufs = NULL;
}
} else if (p->allocated < p->bufs.num) {
/* allocate a new buf if it's still allowed */
b = ngx_create_temp_buf(p->pool, p->bufs.size);
if (b == NULL) {
return NGX_ABORT;
}
p->allocated++;
chain = ngx_alloc_chain_link(p->pool);
if (chain == NULL) {
return NGX_ABORT;
}
chain->buf = b;
chain->next = NULL;
} else if (!p->cacheable
&& p->downstream->data == p->output_ctx
&& p->downstream->write->ready
&& !p->downstream->write->delayed)
{
/*
* if the bufs are not needed to be saved in a cache and
* a downstream is ready then write the bufs to a downstream
*/
p->upstream_blocked = 1;
ngx_log_debug0(NGX_LOG_DEBUG_EVENT, p->log, 0,
"pipe downstream ready");
break;
} else if (p->cacheable
|| p->temp_file->offset < p->max_temp_file_size)
{
/*
* if it is allowed, then save some bufs from r->in
* to a temporary file, and add them to a r->out chain
*/
rc = ngx_event_pipe_write_chain_to_temp_file(p);
ngx_log_debug1(NGX_LOG_DEBUG_EVENT, p->log, 0,
"pipe temp offset: %O", p->temp_file->offset);
if (rc == NGX_BUSY) {
break;
}
if (rc == NGX_AGAIN) {
if (ngx_event_flags & NGX_USE_LEVEL_EVENT
&& p->upstream->read->active
&& p->upstream->read->ready)
{
if (ngx_del_event(p->upstream->read, NGX_READ_EVENT, 0)
== NGX_ERROR)
{
return NGX_ABORT;
}
}
}
if (rc != NGX_OK) {
return rc;
}
chain = p->free_raw_bufs;
if (p->single_buf) {
p->free_raw_bufs = p->free_raw_bufs->next;
chain->next = NULL;
} else {
p->free_raw_bufs = NULL;
}
} else {
/* there are no bufs to read in */
ngx_log_debug0(NGX_LOG_DEBUG_EVENT, p->log, 0,
"no pipe bufs to read in");
break;
}
n = p->upstream->recv_chain(p->upstream, chain);
ngx_log_debug1(NGX_LOG_DEBUG_EVENT, p->log, 0,
"pipe recv chain: %z", n);
if (p->free_raw_bufs) {
chain->next = p->free_raw_bufs;
}
p->free_raw_bufs = chain;
if (n == NGX_ERROR) {
p->upstream_error = 1;
return NGX_ERROR;
}
if (n == NGX_AGAIN) {
if (p->single_buf) {
ngx_event_pipe_remove_shadow_links(chain->buf);
}
break;
}
p->read = 1;
if (n == 0) {
p->upstream_eof = 1;
break;
}
}
p->read_length += n;
cl = chain;
p->free_raw_bufs = NULL;
while (cl && n > 0) {
ngx_event_pipe_remove_shadow_links(cl->buf);
size = cl->buf->end - cl->buf->last;
if (n >= size) {
cl->buf->last = cl->buf->end;
/* STUB */ cl->buf->num = p->num++;
if (p->input_filter(p, cl->buf) == NGX_ERROR) {
return NGX_ABORT;
}
n -= size;
ln = cl;
cl = cl->next;
ngx_free_chain(p->pool, ln);
} else {
cl->buf->last += n;
n = 0;
}
}
if (cl) {
for (ln = cl; ln->next; ln = ln->next) { /* void */ }
ln->next = p->free_raw_bufs;
p->free_raw_bufs = cl;
}
}
#if (NGX_DEBUG)
for (cl = p->busy; cl; cl = cl->next) {
ngx_log_debug8(NGX_LOG_DEBUG_EVENT, p->log, 0,
"pipe buf busy s:%d t:%d f:%d "
"%p, pos %p, size: %z "
"file: %O, size: %z",
(cl->buf->shadow ? 1 : 0),
cl->buf->temporary, cl->buf->in_file,
cl->buf->start, cl->buf->pos,
cl->buf->last - cl->buf->pos,
cl->buf->file_pos,
cl->buf->file_last - cl->buf->file_pos);
}
for (cl = p->out; cl; cl = cl->next) {
ngx_log_debug8(NGX_LOG_DEBUG_EVENT, p->log, 0,
"pipe buf out s:%d t:%d f:%d "
"%p, pos %p, size: %z "
"file: %O, size: %z",
(cl->buf->shadow ? 1 : 0),
cl->buf->temporary, cl->buf->in_file,
cl->buf->start, cl->buf->pos,
cl->buf->last - cl->buf->pos,
cl->buf->file_pos,
cl->buf->file_last - cl->buf->file_pos);
}
for (cl = p->in; cl; cl = cl->next) {
ngx_log_debug8(NGX_LOG_DEBUG_EVENT, p->log, 0,
"pipe buf in s:%d t:%d f:%d "
"%p, pos %p, size: %z "
"file: %O, size: %z",
(cl->buf->shadow ? 1 : 0),
cl->buf->temporary, cl->buf->in_file,
cl->buf->start, cl->buf->pos,
cl->buf->last - cl->buf->pos,
cl->buf->file_pos,
cl->buf->file_last - cl->buf->file_pos);
}
for (cl = p->free_raw_bufs; cl; cl = cl->next) {
ngx_log_debug8(NGX_LOG_DEBUG_EVENT, p->log, 0,
"pipe buf free s:%d t:%d f:%d "
"%p, pos %p, size: %z "
"file: %O, size: %z",
(cl->buf->shadow ? 1 : 0),
cl->buf->temporary, cl->buf->in_file,
cl->buf->start, cl->buf->pos,
cl->buf->last - cl->buf->pos,
cl->buf->file_pos,
cl->buf->file_last - cl->buf->file_pos);
}
#endif
if ((p->upstream_eof || p->upstream_error) && p->free_raw_bufs) {
/* STUB */ p->free_raw_bufs->buf->num = p->num++;
if (p->input_filter(p, p->free_raw_bufs->buf) == NGX_ERROR) {
return NGX_ABORT;
}
p->free_raw_bufs = p->free_raw_bufs->next;
if (p->free_bufs && p->buf_to_file == NULL) {
for (cl = p->free_raw_bufs; cl; cl = cl->next) {
if (cl->buf->shadow == NULL) {
ngx_pfree(p->pool, cl->buf->start);
}
}
}
}
if (p->cacheable && p->in) {
if (ngx_event_pipe_write_chain_to_temp_file(p) == NGX_ABORT) {
return NGX_ABORT;
}
}
return NGX_OK;
}
static ngx_int_t
ngx_http_v2_data_frame_handler(ngx_http_v2_connection_t *h2c,
ngx_http_v2_out_frame_t *frame)
{
ngx_buf_t *buf;
ngx_chain_t *cl, *ln;
ngx_http_v2_stream_t *stream;
stream = frame->stream;
cl = frame->first;
if (cl->buf->tag == (ngx_buf_tag_t) &ngx_http_v2_module) {
if (cl->buf->pos != cl->buf->last) {
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
"http2:%ui DATA frame %p was sent partially",
stream->node->id, frame);
return NGX_AGAIN;
}
ln = cl->next;
cl->next = stream->free_frame_headers;
stream->free_frame_headers = cl;
if (cl == frame->last) {
goto done;
}
cl = ln;
}
for ( ;; ) {
if (cl->buf->tag == (ngx_buf_tag_t) &ngx_http_v2_filter_get_shadow) {
buf = cl->buf->shadow;
if (ngx_buf_in_memory(buf)) {
buf->pos = cl->buf->pos;
}
if (buf->in_file) {
buf->file_pos = cl->buf->file_pos;
}
}
if (ngx_buf_size(cl->buf) != 0) {
if (cl != frame->first) {
frame->first = cl;
ngx_http_v2_handle_stream(h2c, stream);
}
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
"http2:%ui DATA frame %p was sent partially",
stream->node->id, frame);
return NGX_AGAIN;
}
ln = cl->next;
if (cl->buf->tag == (ngx_buf_tag_t) &ngx_http_v2_filter_get_shadow) {
cl->next = stream->free_bufs;
stream->free_bufs = cl;
} else {
ngx_free_chain(stream->request->pool, cl);
}
if (cl == frame->last) {
goto done;
}
cl = ln;
}
done:
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0,
"http2:%ui DATA frame %p was sent",
stream->node->id, frame);
stream->request->header_size += NGX_HTTP_V2_FRAME_HEADER_SIZE;
ngx_http_v2_handle_frame(stream, frame);
ngx_http_v2_handle_stream(h2c, stream);
return NGX_OK;
}
static ngx_chain_t *
ngx_http_v2_send_chain(ngx_connection_t *fc, ngx_chain_t *in, off_t limit)
{
off_t size, offset;
size_t rest, frame_size;
ngx_chain_t *cl, *out, **ln;
ngx_http_request_t *r;
ngx_http_v2_stream_t *stream;
ngx_http_v2_loc_conf_t *h2lcf;
ngx_http_v2_out_frame_t *frame;
ngx_http_v2_connection_t *h2c;
r = fc->data;
stream = r->stream;
#if (NGX_SUPPRESS_WARN)
size = 0;
#endif
while (in) {
size = ngx_buf_size(in->buf);
if (size || in->buf->last_buf) {
break;
}
in = in->next;
}
if (in == NULL) {
if (stream->queued) {
fc->write->active = 1;
fc->write->ready = 0;
} else {
fc->buffered &= ~NGX_HTTP_V2_BUFFERED;
}
return NULL;
}
h2c = stream->connection;
if (size && ngx_http_v2_flow_control(h2c, stream) == NGX_DECLINED) {
fc->write->active = 1;
fc->write->ready = 0;
return in;
}
if (in->buf->tag == (ngx_buf_tag_t) &ngx_http_v2_filter_get_shadow) {
cl = ngx_alloc_chain_link(r->pool);
if (cl == NULL) {
return NGX_CHAIN_ERROR;
}
cl->buf = in->buf;
in->buf = cl->buf->shadow;
offset = ngx_buf_in_memory(in->buf)
? (cl->buf->pos - in->buf->pos)
: (cl->buf->file_pos - in->buf->file_pos);
cl->next = stream->free_bufs;
stream->free_bufs = cl;
} else {
offset = 0;
}
if (limit == 0 || limit > (off_t) h2c->send_window) {
limit = h2c->send_window;
}
if (limit > stream->send_window) {
limit = (stream->send_window > 0) ? stream->send_window : 0;
}
h2lcf = ngx_http_get_module_loc_conf(r, ngx_http_v2_module);
frame_size = (h2lcf->chunk_size < h2c->frame_size)
? h2lcf->chunk_size : h2c->frame_size;
#if (NGX_SUPPRESS_WARN)
cl = NULL;
#endif
for ( ;; ) {
if ((off_t) frame_size > limit) {
frame_size = (size_t) limit;
}
ln = &out;
rest = frame_size;
while ((off_t) rest >= size) {
if (offset) {
cl = ngx_http_v2_filter_get_shadow(stream, in->buf,
offset, size);
if (cl == NULL) {
return NGX_CHAIN_ERROR;
}
offset = 0;
} else {
cl = ngx_alloc_chain_link(r->pool);
if (cl == NULL) {
return NGX_CHAIN_ERROR;
}
cl->buf = in->buf;
}
*ln = cl;
ln = &cl->next;
rest -= (size_t) size;
in = in->next;
if (in == NULL) {
frame_size -= rest;
rest = 0;
break;
}
size = ngx_buf_size(in->buf);
}
if (rest) {
cl = ngx_http_v2_filter_get_shadow(stream, in->buf, offset, rest);
if (cl == NULL) {
return NGX_CHAIN_ERROR;
}
cl->buf->flush = 0;
cl->buf->last_buf = 0;
*ln = cl;
offset += rest;
size -= rest;
}
frame = ngx_http_v2_filter_get_data_frame(stream, frame_size, out, cl);
if (frame == NULL) {
return NGX_CHAIN_ERROR;
}
ngx_http_v2_queue_frame(h2c, frame);
h2c->send_window -= frame_size;
stream->send_window -= frame_size;
stream->queued++;
if (in == NULL) {
break;
}
limit -= frame_size;
if (limit == 0) {
break;
}
}
if (offset) {
cl = ngx_http_v2_filter_get_shadow(stream, in->buf, offset, size);
if (cl == NULL) {
return NGX_CHAIN_ERROR;
}
in->buf = cl->buf;
ngx_free_chain(r->pool, cl);
}
if (ngx_http_v2_filter_send(fc, stream) == NGX_ERROR) {
return NGX_CHAIN_ERROR;
}
if (in && ngx_http_v2_flow_control(h2c, stream) == NGX_DECLINED) {
fc->write->active = 1;
fc->write->ready = 0;
}
return in;
}
void free(ngx_pool_t* pool) const
{
ngx_free_chain(pool, get());
}
static ngx_int_t
ngx_http_spdy_data_frame_handler(ngx_http_spdy_connection_t *sc,
ngx_http_spdy_out_frame_t *frame)
{
ngx_chain_t *cl, *ln;
ngx_http_spdy_stream_t *stream;
stream = frame->stream;
cl = frame->first;
if (cl->buf->tag == (ngx_buf_tag_t) &ngx_http_spdy_serverpush_filter_module) {
if (cl->buf->pos != cl->buf->last) {
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, sc->connection->log, 0,
"spdy:%ui DATA frame %p was sent partially",
stream->id, frame);
return NGX_AGAIN;
}
ln = cl->next;
cl->next = stream->free_data_headers;
stream->free_data_headers = cl;
if (cl == frame->last) {
goto done;
}
cl = ln;
}
for ( ;; ) {
if (ngx_buf_size(cl->buf) != 0) {
if (cl != frame->first) {
frame->first = cl;
ngx_http_spdy_handle_stream(sc, stream);
}
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, sc->connection->log, 0,
"spdy:%ui DATA frame %p was sent partially",
stream->id, frame);
return NGX_AGAIN;
}
ln = cl->next;
ngx_free_chain(stream->request->pool, cl);
if (cl == frame->last) {
goto done;
}
cl = ln;
}
done:
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, sc->connection->log, 0,
"spdy:%ui DATA frame %p was sent", stream->id, frame);
stream->request->header_size += NGX_SPDY_FRAME_HEADER_SIZE;
ngx_http_spdy_handle_frame(stream, frame);
ngx_http_spdy_handle_stream(sc, stream);
return NGX_OK;
}
static ngx_int_t
ngx_http_write_request_body(ngx_http_request_t *r)
{
ssize_t n;
ngx_chain_t *cl, *ln;
ngx_temp_file_t *tf;
ngx_http_request_body_t *rb;
ngx_http_core_loc_conf_t *clcf;
rb = r->request_body;
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"http write client request body, bufs %p", rb->bufs);
if (rb->temp_file == NULL) {
tf = ngx_pcalloc(r->pool, sizeof(ngx_temp_file_t));
if (tf == NULL) {
return NGX_ERROR;
}
clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
tf->file.fd = NGX_INVALID_FILE;
tf->file.log = r->connection->log;
tf->path = clcf->client_body_temp_path;
tf->pool = r->pool;
tf->warn = "a client request body is buffered to a temporary file";
tf->log_level = r->request_body_file_log_level;
tf->persistent = r->request_body_in_persistent_file;
tf->clean = r->request_body_in_clean_file;
if (r->request_body_file_group_access) {
tf->access = 0660;
}
rb->temp_file = tf;
if (rb->bufs == NULL) {
/* empty body with r->request_body_in_file_only */
if (ngx_create_temp_file(&tf->file, tf->path, tf->pool,
tf->persistent, tf->clean, tf->access)
!= NGX_OK)
{
return NGX_ERROR;
}
return NGX_OK;
}
}
if (rb->bufs == NULL) {
return NGX_OK;
}
n = ngx_write_chain_to_temp_file(rb->temp_file, rb->bufs);
/* TODO: n == 0 or not complete and level event */
if (n == NGX_ERROR) {
return NGX_ERROR;
}
rb->temp_file->offset += n;
/* mark all buffers as written */
for (cl = rb->bufs; cl; /* void */) {
cl->buf->pos = cl->buf->last;
ln = cl;
cl = cl->next;
ngx_free_chain(r->pool, ln);
}
rb->bufs = NULL;
return NGX_OK;
}
/* 参数r是对应的请求，in是保存本次待发送数据的链表缓冲区 */
ngx_int_t
ngx_http_write_filter(ngx_http_request_t *r, ngx_chain_t *in)
{
off_t size, sent, nsent, limit;
ngx_uint_t last, flush;
ngx_msec_t delay;
ngx_chain_t *cl, *ln, **ll, *chain;
ngx_connection_t *c;
ngx_http_core_loc_conf_t *clcf;
/* 获取当前请求所对应的连接 */
c = r->connection;
/*
* 检查当前连接的错误标志位error，若该标志位为1，
* 表示当前请求出错，返回NGX_ERROR；
*/
if (c->error) {
return NGX_ERROR;
}
size = 0;
flush = 0;
last = 0;
ll = &r->out;
/* find the size, the flush point and the last link of the saved chain */
/*
* 遍历当前请求out链表缓冲区，计算剩余响应报文的长度；
* 因为当响应报文一次性不能发送完成时，会把剩余的响应报文保存在out中，
* 相对于本次发送的响应报文数据in来说（即该方法所传入的参数in），
* out链表缓冲区保存的是前一次剩余的响应报文；
*/
for (cl = r->out; cl; cl = cl->next) {
ll = &cl->next;
ngx_log_debug7(NGX_LOG_DEBUG_EVENT, c->log, 0,
"write old buf t:%d f:%d %p, pos %p, size: %z "
"file: %O, size: %z",
cl->buf->temporary, cl->buf->in_file,
cl->buf->start, cl->buf->pos,
cl->buf->last - cl->buf->pos,
cl->buf->file_pos,
cl->buf->file_last - cl->buf->file_pos);
#if 1
if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) {
ngx_log_error(NGX_LOG_ALERT, c->log, 0,
"zero size buf in writer "
"t:%d r:%d f:%d %p %p-%p %p %O-%O",
cl->buf->temporary,
cl->buf->recycled,
cl->buf->in_file,
cl->buf->start,
cl->buf->pos,
cl->buf->last,
cl->buf->file,
cl->buf->file_pos,
cl->buf->file_last);
ngx_debug_point();
return NGX_ERROR;
}
#endif
size += ngx_buf_size(cl->buf);
if (cl->buf->flush || cl->buf->recycled) {
flush = 1;
}
if (cl->buf->last_buf) {
last = 1;
}
}
/* add the new chain to the existent one */
/*
* 将本次待发送的响应报文的缓冲区in添加到out链表缓冲区的尾部，
* 并计算待发送响应报文总的长度size；
*/
for (ln = in; ln; ln = ln->next) {
cl = ngx_alloc_chain_link(r->pool);
if (cl == NULL) {
return NGX_ERROR;
}
cl->buf = ln->buf;
*ll = cl;/* 由上面可知 ll=&r->out */
ll = &cl->next;
ngx_log_debug7(NGX_LOG_DEBUG_EVENT, c->log, 0,
"write new buf t:%d f:%d %p, pos %p, size: %z "
"file: %O, size: %z",
cl->buf->temporary, cl->buf->in_file,
cl->buf->start, cl->buf->pos,
cl->buf->last - cl->buf->pos,
cl->buf->file_pos,
cl->buf->file_last - cl->buf->file_pos);
#if 1
if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) {
ngx_log_error(NGX_LOG_ALERT, c->log, 0,
"zero size buf in writer "
"t:%d r:%d f:%d %p %p-%p %p %O-%O",
cl->buf->temporary,
cl->buf->recycled,
cl->buf->in_file,
cl->buf->start,
cl->buf->pos,
cl->buf->last,
cl->buf->file,
cl->buf->file_pos,
cl->buf->file_last);
ngx_debug_point();
return NGX_ERROR;
}
#endif
size += ngx_buf_size(cl->buf);
if (cl->buf->flush || cl->buf->recycled) {
flush = 1;
}
if (cl->buf->last_buf) {
last = 1;
}
}
*ll = NULL;
ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0,
"http write filter: l:%d f:%d s:%O", last, flush, size);
/* 获取ngx_http_core_module模块的loc级别配置项结构体 */
clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
/*
* avoid the output if there are no last buf, no flush point,
* there are the incoming bufs and the size of all bufs
* is smaller than "postpone_output" directive
*/
/*
* 若out链表最后一块缓冲区last为空，且没有强制性刷新flush链表缓冲区out，
* 且当前有待发响应报文in，但是待发送响应报文总的长度size小于预设可发送条件值postpone_output,
* 则本次不能发送响应报文，继续保存在out链表缓冲区中，以待下次才发送；
* 其中postpone_output预设值我们可以在配置文件nginx.conf中设置；
*/
if (!last && !flush && in && size < (off_t) clcf->postpone_output) {
return NGX_OK;
}
/*
* 检查当前连接上写事件的delayed标志位，
* 若该标志位为1，表示需要延迟发送响应报文，
* 因此，返回NGX_AGAIN，表示延迟发送；
*/
if (c->write->delayed) {
c->buffered |= NGX_HTTP_WRITE_BUFFERED;
return NGX_AGAIN;
}
if (size == 0
&& !(c->buffered & NGX_LOWLEVEL_BUFFERED)
&& !(last && c->need_last_buf))
{
if (last || flush) {
for (cl = r->out; cl; /* void */) {
ln = cl;
cl = cl->next;
ngx_free_chain(r->pool, ln);
}
r->out = NULL;
c->buffered &= ~NGX_HTTP_WRITE_BUFFERED;
return NGX_OK;
}
ngx_log_error(NGX_LOG_ALERT, c->log, 0,
"the http output chain is empty");
ngx_debug_point();
return NGX_ERROR;
}
/*
* 检查当前请求的限速标志位limit_rate，
* 若该标志位为大于0，表示发送响应报文的速度不能超过limit_rate指定的速度；
*/
if (r->limit_rate) {
if (r->limit_rate_after == 0) {
r->limit_rate_after = clcf->limit_rate_after;
}
/* 计算发送速度是否超过限速值 */
limit = (off_t) r->limit_rate * (ngx_time() - r->start_sec + 1)
- (c->sent - r->limit_rate_after);
/*
* 若当前发送响应报文的速度超过限速值，则写事件标志位delayed设为1，
* 并把该写事件添加到定时器机制中，并且将buffered设置为可写状态，
* 返回NGX_AGAIN，表示链表缓冲区out还保存剩余待发送的响应报文；
*/
if (limit <= 0) {
c->write->delayed = 1;
ngx_add_timer(c->write,
(ngx_msec_t) (- limit * 1000 / r->limit_rate + 1));
c->buffered |= NGX_HTTP_WRITE_BUFFERED;
return NGX_AGAIN;
}
if (clcf->sendfile_max_chunk
&& (off_t) clcf->sendfile_max_chunk < limit)
{
limit = clcf->sendfile_max_chunk;
}
} else {
limit = clcf->sendfile_max_chunk;
}
/* 若不需要减速，或没有设置速度限制，则向客户端发送响应字符流 */
sent = c->sent;
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
"http write filter limit %O", limit);
chain = c->send_chain(c, r->out, limit);
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
"http write filter %p", chain);
if (chain == NGX_CHAIN_ERROR) {
c->error = 1;
return NGX_ERROR;
}
/* 再次检查limit_rate标志位 */
if (r->limit_rate) {
nsent = c->sent;
if (r->limit_rate_after) {
sent -= r->limit_rate_after;
if (sent < 0) {
sent = 0;
}
nsent -= r->limit_rate_after;
if (nsent < 0) {
nsent = 0;
}
}
/* 再次计算当前发送响应报文速度是否超过限制值 */
delay = (ngx_msec_t) ((nsent - sent) * 1000 / r->limit_rate);
/* 若超过，需要限速，并把写事件添加到定时器机制中 */
if (delay > 0) {
limit = 0;
c->write->delayed = 1;
ngx_add_timer(c->write, delay);
}
}
if (limit
&& c->write->ready
&& c->sent - sent >= limit - (off_t) (2 * ngx_pagesize))
{
c->write->delayed = 1;
ngx_add_timer(c->write, 1);
}
/* 重新调整链表缓冲区out的情况，把已发送数据的缓冲区内存回收 */
for (cl = r->out; cl && cl != chain; /* void */) {
ln = cl;
cl = cl->next;
ngx_free_chain(r->pool, ln);
}
/* 检查out链表缓冲区是否还有数据 */
r->out = chain;
/* 若还有数据，返回NGX_AGAIN，表示还存在待发送的响应报文数据 */
if (chain) {
c->buffered |= NGX_HTTP_WRITE_BUFFERED;
return NGX_AGAIN;
}
c->buffered &= ~NGX_HTTP_WRITE_BUFFERED;
if ((c->buffered & NGX_LOWLEVEL_BUFFERED) && r->postponed == NULL) {
return NGX_AGAIN;
}
/* 若已发送全部数据则返回NGX_OK */
return NGX_OK;
}
ngx_int_t
ngx_chain_writer(void *data, ngx_chain_t *in)
{
ngx_chain_writer_ctx_t *ctx = data;
off_t size;
ngx_chain_t *cl, *ln, *chain;
ngx_connection_t *c;
c = ctx->connection;
for (size = 0; in; in = in->next) {
#if 1
if (ngx_buf_size(in->buf) == 0 && !ngx_buf_special(in->buf)) {
ngx_log_error(NGX_LOG_ALERT, ctx->pool->log, 0,
"zero size buf in chain writer "
"t:%d r:%d f:%d %p %p-%p %p %O-%O",
in->buf->temporary,
in->buf->recycled,
in->buf->in_file,
in->buf->start,
in->buf->pos,
in->buf->last,
in->buf->file,
in->buf->file_pos,
in->buf->file_last);
ngx_debug_point();
continue;
}
#endif
size += ngx_buf_size(in->buf);
ngx_log_debug2(NGX_LOG_DEBUG_CORE, c->log, 0,
"chain writer buf fl:%d s:%uO",
in->buf->flush, ngx_buf_size(in->buf));
cl = ngx_alloc_chain_link(ctx->pool);
if (cl == NULL) {
return NGX_ERROR;
}
cl->buf = in->buf;
cl->next = NULL;
*ctx->last = cl;
ctx->last = &cl->next;
}
ngx_log_debug1(NGX_LOG_DEBUG_CORE, c->log, 0,
"chain writer in: %p", ctx->out);
for (cl = ctx->out; cl; cl = cl->next) {
#if 1
if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) {
ngx_log_error(NGX_LOG_ALERT, ctx->pool->log, 0,
"zero size buf in chain writer "
"t:%d r:%d f:%d %p %p-%p %p %O-%O",
cl->buf->temporary,
cl->buf->recycled,
cl->buf->in_file,
cl->buf->start,
cl->buf->pos,
cl->buf->last,
cl->buf->file,
cl->buf->file_pos,
cl->buf->file_last);
ngx_debug_point();
continue;
}
#endif
size += ngx_buf_size(cl->buf);
}
if (size == 0 && !c->buffered) {
return NGX_OK;
}
chain = c->send_chain(c, ctx->out, ctx->limit);
ngx_log_debug1(NGX_LOG_DEBUG_CORE, c->log, 0,
"chain writer out: %p", chain);
if (chain == NGX_CHAIN_ERROR) {
return NGX_ERROR;
}
for (cl = ctx->out; cl && cl != chain; /* void */) {
ln = cl;
cl = cl->next;
ngx_free_chain(ctx->pool, ln);
}
ctx->out = chain;
if (ctx->out == NULL) {
ctx->last = &ctx->out;
if (!c->buffered) {
return NGX_OK;
}
}
return NGX_AGAIN;
}
ngx_int_t
ngx_chain_writer(void *data, ngx_chain_t *in)
{
ngx_chain_writer_ctx_t *ctx = data;
off_t size;
ngx_chain_t *cl, *ct;
ngx_connection_t *c;
c = ctx->connection;
for (size = 0; in; in = in->next) {
#if 1
if (ngx_buf_size(in->buf) == 0 && !ngx_buf_special(in->buf)) {
ngx_debug_point();
}
#endif
size += ngx_buf_size(in->buf);
ngx_log_debug2(NGX_LOG_DEBUG_CORE, c->log, 0,
"chain writer buf fl:%d s:%uO",
in->buf->flush, ngx_buf_size(in->buf));
cl = ngx_alloc_chain_link(ctx->pool);
if (cl == NULL) {
return NGX_ERROR;
}
cl->buf = in->buf;
cl->next = NULL;
*ctx->last = cl;
ctx->last = &cl->next;
}
ngx_log_debug1(NGX_LOG_DEBUG_CORE, c->log, 0,
"chain writer in: %p", ctx->out);
for (cl = ctx->out; cl; cl = cl->next) {
#if 1
if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) {
ngx_debug_point();
}
#endif
size += ngx_buf_size(cl->buf);
}
if (size == 0 && !c->buffered) {
return NGX_OK;
}
cl = ctx->out;
ctx->out = c->send_chain(c, ctx->out, ctx->limit);
ngx_log_debug1(NGX_LOG_DEBUG_CORE, c->log, 0,
"chain writer out: %p", ctx->out);
if (ctx->out == NGX_CHAIN_ERROR) {
return NGX_ERROR;
}
while (cl != ctx->out) {
ct = cl->next;
ngx_free_chain(ctx->pool, cl);
cl = ct;
}
if (ctx->out == NULL) {
ctx->last = &ctx->out;
if (!c->buffered) {
return NGX_OK;
}
}
return NGX_AGAIN;
}
// 真正的向客户端发送数据，调用send_chain
// 也由ngx_http_set_write_handler设置epoll的写事件触发
// 如果数据发送不完，就保存在r->out里，返回again
// 需要再次发生可写事件才能发送
// 不是last、flush，且数据量较小（默认1460）
// 那么这次就不真正调用write发送，减少系统调用的次数，提高性能
// 在此函数里处理限速
ngx_int_t
ngx_http_write_filter(ngx_http_request_t *r, ngx_chain_t *in)
{
off_t size, sent, nsent, limit;
ngx_uint_t last, flush, sync;
ngx_msec_t delay;
ngx_chain_t *cl, *ln, **ll, *chain;
ngx_connection_t *c;
ngx_http_core_loc_conf_t *clcf;
// 获取连接对象
c = r->connection;
// 如果连接有错误就不能发送数据
if (c->error) {
return NGX_ERROR;
}
// 数据的长度，
size = 0;
// 是否flush的标志
flush = 0;
// 是否sync的标志
sync = 0;
// 是否是最后一块数据，即数据全部发送完毕
last = 0;
// 请求里存储的待发送的数据链表
// 可能是之前因为again而未能发送出去
ll = &r->out;
/* find the size, the flush point and the last link of the saved chain */
// 先遍历当前请求里待发送的数据链表，计算长度
for (cl = r->out; cl; cl = cl->next) {
ll = &cl->next;
ngx_log_debug7(NGX_LOG_DEBUG_EVENT, c->log, 0,
"write old buf t:%d f:%d %p, pos %p, size: %z "
"file: %O, size: %O",
cl->buf->temporary, cl->buf->in_file,
cl->buf->start, cl->buf->pos,
cl->buf->last - cl->buf->pos,
cl->buf->file_pos,
cl->buf->file_last - cl->buf->file_pos);
#if 1
// 缓冲区0长度，但不是flush、sync等控制用缓冲区，报错
if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) {
ngx_log_error(NGX_LOG_ALERT, c->log, 0,
"zero size buf in writer "
"t:%d r:%d f:%d %p %p-%p %p %O-%O",
cl->buf->temporary,
cl->buf->recycled,
cl->buf->in_file,
cl->buf->start,
cl->buf->pos,
cl->buf->last,
cl->buf->file,
cl->buf->file_pos,
cl->buf->file_last);
ngx_debug_point();
return NGX_ERROR;
}
#endif
// 累计数据长度
size += ngx_buf_size(cl->buf);
// flush标志
if (cl->buf->flush || cl->buf->recycled) {
flush = 1;
}
// sync标志
if (cl->buf->sync) {
sync = 1;
}
// 发送结束的标志
if (cl->buf->last_buf) {
last = 1;
}
}
/* add the new chain to the existent one */
// 遍历新的数据链表，计算长度
// 把in链表里的数据挂到r->out链表后面
for (ln = in; ln; ln = ln->next) {
// 分配一个新的链表节点
cl = ngx_alloc_chain_link(r->pool);
if (cl == NULL) {
return NGX_ERROR;
}
// 拷贝缓冲区，然后挂到out后面
cl->buf = ln->buf;
*ll = cl;
ll = &cl->next;
ngx_log_debug7(NGX_LOG_DEBUG_EVENT, c->log, 0,
"write new buf t:%d f:%d %p, pos %p, size: %z "
"file: %O, size: %O",
cl->buf->temporary, cl->buf->in_file,
cl->buf->start, cl->buf->pos,
cl->buf->last - cl->buf->pos,
cl->buf->file_pos,
cl->buf->file_last - cl->buf->file_pos);
#if 1
// 缓冲区0长度，但不是flush、sync等控制用缓冲区，报错
if (ngx_buf_size(cl->buf) == 0 && !ngx_buf_special(cl->buf)) {
ngx_log_error(NGX_LOG_ALERT, c->log, 0,
"zero size buf in writer "
"t:%d r:%d f:%d %p %p-%p %p %O-%O",
cl->buf->temporary,
cl->buf->recycled,
cl->buf->in_file,
cl->buf->start,
cl->buf->pos,
cl->buf->last,
cl->buf->file,
cl->buf->file_pos,
cl->buf->file_last);
ngx_debug_point();
return NGX_ERROR;
}
#endif
// 累计数据长度
size += ngx_buf_size(cl->buf);
// flush标志
if (cl->buf->flush || cl->buf->recycled) {
flush = 1;
}
// sync标志
if (cl->buf->sync) {
sync = 1;
}
// 发送结束的标志
if (cl->buf->last_buf) {
last = 1;
}
}
// 链表的最后节点，必须设置为空指针
*ll = NULL;
ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0,
"http write filter: l:%ui f:%ui s:%O", last, flush, size);
clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
/*
* avoid the output if there are no last buf, no flush point,
* there are the incoming bufs and the size of all bufs
* is smaller than "postpone_output" directive
*/
// 不是last、flush，且数据量较小（默认1460）
// 那么这次就不真正调用write发送，减少系统调用的次数，提高性能
if (!last && !flush && in && size < (off_t) clcf->postpone_output) {
return NGX_OK;
}
// flush，用户要求立即发送
// last，所有的数据都集齐了，之后不会有新数据
// size > postpone_output，数据已经积累的足够多，应该发送了
// delayed表示需要限速，那么就暂不发送
if (c->write->delayed) {
// 置标志位，表示连接有数据缓冲待发送
c->buffered |= NGX_HTTP_WRITE_BUFFERED;
return NGX_AGAIN;
}
// 数据长度为0
if (size == 0
&& !(c->buffered & NGX_LOWLEVEL_BUFFERED)
&& !(last && c->need_last_buf))
{
// 释放r->out里的节点
if (last || flush || sync) {
for (cl = r->out; cl; /* void */) {
ln = cl;
cl = cl->next;
ngx_free_chain(r->pool, ln);
}
r->out = NULL;
c->buffered &= ~NGX_HTTP_WRITE_BUFFERED;
return NGX_OK;
}
ngx_log_error(NGX_LOG_ALERT, c->log, 0,
"the http output chain is empty");
ngx_debug_point();
return NGX_ERROR;
}
// 处理限速，不研究
if (r->limit_rate) {
if (r->limit_rate_after == 0) {
r->limit_rate_after = clcf->limit_rate_after;
}
limit = (off_t) r->limit_rate * (ngx_time() - r->start_sec + 1)
- (c->sent - r->limit_rate_after);
if (limit <= 0) {
c->write->delayed = 1;
delay = (ngx_msec_t) (- limit * 1000 / r->limit_rate + 1);
ngx_add_timer(c->write, delay);
c->buffered |= NGX_HTTP_WRITE_BUFFERED;
return NGX_AGAIN;
}
if (clcf->sendfile_max_chunk
&& (off_t) clcf->sendfile_max_chunk < limit)
{
limit = clcf->sendfile_max_chunk;
}
} else {
// 不限速，使用配置的参数，默认是0，即不限制，尽量多发
limit = clcf->sendfile_max_chunk;
}
// 已经发送的字节数
sent = c->sent;
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
"http write filter limit %O", limit);
// 调用send_chain发送out链表
// 实际上调用的是ngx_writev_chain
//
// 发送limit长度（字节数）的数据
// 如果事件not ready，即暂不可写，那么立即返回，无动作
// 要求缓冲区必须在内存里，否则报错
// 最后返回消费缓冲区之后的链表指针
// 发送出错、遇到again、发送完毕，这三种情况函数结束
// 返回的是最后发送到的链表节点指针
chain = c->send_chain(c, r->out, limit);
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
"http write filter %p", chain);
if (chain == NGX_CHAIN_ERROR) {
c->error = 1;
return NGX_ERROR;
}
// 处理限速，不研究
if (r->limit_rate) {
nsent = c->sent;
if (r->limit_rate_after) {
sent -= r->limit_rate_after;
if (sent < 0) {
sent = 0;
}
nsent -= r->limit_rate_after;
if (nsent < 0) {
nsent = 0;
}
}
delay = (ngx_msec_t) ((nsent - sent) * 1000 / r->limit_rate);
if (delay > 0) {
limit = 0;
c->write->delayed = 1;
ngx_add_timer(c->write, delay);
}
}
// 处理限速，不研究
if (limit
&& c->write->ready
&& c->sent - sent >= limit - (off_t) (2 * ngx_pagesize))
{
c->write->delayed = 1;
ngx_add_timer(c->write, 1);
}
// 在out链表里把已经发送过的节点都回收，供以后复用
for (cl = r->out; cl && cl != chain; /* void */) {
ln = cl;
cl = cl->next;
ngx_free_chain(r->pool, ln);
}
// out指向新的位置
r->out = chain;
// 不是空指针，表明还有数据没发完
if (chain) {
// 置标志位，表示连接有数据缓冲待发送
c->buffered |= NGX_HTTP_WRITE_BUFFERED;
return NGX_AGAIN;
}
// 已经发送完了
// 清除缓冲标志位
c->buffered &= ~NGX_HTTP_WRITE_BUFFERED;
// NGX_LOWLEVEL_BUFFERED目前似乎在nginx里还没有用到
if ((c->buffered & NGX_LOWLEVEL_BUFFERED) && r->postponed == NULL) {
return NGX_AGAIN;
}
return NGX_OK;
}
