2 * Copyright (c) 2009-2012 Niels Provos and Nick Mathewson
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5 * modification, are permitted provided that the following conditions
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30 This module implements overlapped read and write functions for evbuffer
33 #include "event2/event-config.h"
34 #include "evconfig-private.h"
36 #include "event2/buffer.h"
37 #include "event2/buffer_compat.h"
38 #include "event2/util.h"
39 #include "event2/thread.h"
40 #include "util-internal.h"
41 #include "evthread-internal.h"
42 #include "evbuffer-internal.h"
43 #include "iocp-internal.h"
44 #include "mm-internal.h"
50 #define MAX_WSABUFS 16
52 /** An evbuffer that can handle overlapped IO. */
53 struct evbuffer_overlapped {
54 struct evbuffer buffer;
55 /** The socket that we're doing overlapped IO on. */
58 /** pending I/O type */
59 unsigned read_in_progress : 1;
60 unsigned write_in_progress : 1;
62 /** The first pinned chain in the buffer. */
63 struct evbuffer_chain *first_pinned;
65 /** How many chains are pinned; how many of the fields in buffers
68 WSABUF buffers[MAX_WSABUFS];
71 /** Given an evbuffer, return the correponding evbuffer structure, or NULL if
72 * the evbuffer isn't overlapped. */
73 static inline struct evbuffer_overlapped *
74 upcast_evbuffer(struct evbuffer *buf)
76 if (!buf || !buf->is_overlapped)
78 return EVUTIL_UPCAST(buf, struct evbuffer_overlapped, buffer);
81 /** Unpin all the chains noted as pinned in 'eo'. */
83 pin_release(struct evbuffer_overlapped *eo, unsigned flag)
86 struct evbuffer_chain *next, *chain = eo->first_pinned;
88 for (i = 0; i < eo->n_buffers; ++i) {
91 evbuffer_chain_unpin_(chain, flag);
97 evbuffer_commit_read_(struct evbuffer *evbuf, ev_ssize_t nBytes)
99 struct evbuffer_overlapped *buf = upcast_evbuffer(evbuf);
100 struct evbuffer_chain **chainp;
101 size_t remaining, len;
104 EVBUFFER_LOCK(evbuf);
105 EVUTIL_ASSERT(buf->read_in_progress && !buf->write_in_progress);
106 EVUTIL_ASSERT(nBytes >= 0); /* XXXX Can this be false? */
108 evbuffer_unfreeze(evbuf, 0);
110 chainp = evbuf->last_with_datap;
111 if (!((*chainp)->flags & EVBUFFER_MEM_PINNED_R))
112 chainp = &(*chainp)->next;
114 for (i = 0; remaining > 0 && i < (unsigned)buf->n_buffers; ++i) {
115 EVUTIL_ASSERT(*chainp);
116 len = buf->buffers[i].len;
119 (*chainp)->off += len;
120 evbuf->last_with_datap = chainp;
122 chainp = &(*chainp)->next;
125 pin_release(buf, EVBUFFER_MEM_PINNED_R);
127 buf->read_in_progress = 0;
129 evbuf->total_len += nBytes;
130 evbuf->n_add_for_cb += nBytes;
132 evbuffer_invoke_callbacks_(evbuf);
134 evbuffer_decref_and_unlock_(evbuf);
138 evbuffer_commit_write_(struct evbuffer *evbuf, ev_ssize_t nBytes)
140 struct evbuffer_overlapped *buf = upcast_evbuffer(evbuf);
142 EVBUFFER_LOCK(evbuf);
143 EVUTIL_ASSERT(buf->write_in_progress && !buf->read_in_progress);
144 evbuffer_unfreeze(evbuf, 1);
145 evbuffer_drain(evbuf, nBytes);
146 pin_release(buf,EVBUFFER_MEM_PINNED_W);
147 buf->write_in_progress = 0;
148 evbuffer_decref_and_unlock_(evbuf);
152 evbuffer_overlapped_new_(evutil_socket_t fd)
154 struct evbuffer_overlapped *evo;
156 evo = mm_calloc(1, sizeof(struct evbuffer_overlapped));
160 LIST_INIT(&evo->buffer.callbacks);
161 evo->buffer.refcnt = 1;
162 evo->buffer.last_with_datap = &evo->buffer.first;
164 evo->buffer.is_overlapped = 1;
171 evbuffer_launch_write_(struct evbuffer *buf, ev_ssize_t at_most,
172 struct event_overlapped *ol)
174 struct evbuffer_overlapped *buf_o = upcast_evbuffer(buf);
177 struct evbuffer_chain *chain;
181 /* No buffer, or it isn't overlapped */
186 EVUTIL_ASSERT(!buf_o->read_in_progress);
187 if (buf->freeze_start || buf_o->write_in_progress)
189 if (!buf->total_len) {
190 /* Nothing to write */
193 } else if (at_most < 0 || (size_t)at_most > buf->total_len) {
194 at_most = buf->total_len;
196 evbuffer_freeze(buf, 1);
198 buf_o->first_pinned = NULL;
199 buf_o->n_buffers = 0;
200 memset(buf_o->buffers, 0, sizeof(buf_o->buffers));
202 chain = buf_o->first_pinned = buf->first;
204 for (i=0; i < MAX_WSABUFS && chain; ++i, chain=chain->next) {
205 WSABUF *b = &buf_o->buffers[i];
206 b->buf = (char*)( chain->buffer + chain->misalign );
207 evbuffer_chain_pin_(chain, EVBUFFER_MEM_PINNED_W);
209 if ((size_t)at_most > chain->off) {
210 /* XXXX Cast is safe for now, since win32 has no
211 mmaped chains. But later, we need to have this
212 add more WSAbufs if chain->off is greater than
214 b->len = (unsigned long)chain->off;
215 at_most -= chain->off;
217 b->len = (unsigned long)at_most;
223 buf_o->n_buffers = i;
224 evbuffer_incref_(buf);
225 if (WSASend(buf_o->fd, buf_o->buffers, i, &bytesSent, 0,
226 &ol->overlapped, NULL)) {
227 int error = WSAGetLastError();
228 if (error != WSA_IO_PENDING) {
229 /* An actual error. */
230 pin_release(buf_o, EVBUFFER_MEM_PINNED_W);
231 evbuffer_unfreeze(buf, 1);
232 evbuffer_free(buf); /* decref */
237 buf_o->write_in_progress = 1;
240 EVBUFFER_UNLOCK(buf);
245 evbuffer_launch_read_(struct evbuffer *buf, size_t at_most,
246 struct event_overlapped *ol)
248 struct evbuffer_overlapped *buf_o = upcast_evbuffer(buf);
252 struct evbuffer_chain *chain=NULL, **chainp;
255 struct evbuffer_iovec vecs[MAX_WSABUFS];
260 EVUTIL_ASSERT(!buf_o->write_in_progress);
261 if (buf->freeze_end || buf_o->read_in_progress)
264 buf_o->first_pinned = NULL;
265 buf_o->n_buffers = 0;
266 memset(buf_o->buffers, 0, sizeof(buf_o->buffers));
268 if (evbuffer_expand_fast_(buf, at_most, MAX_WSABUFS) == -1)
270 evbuffer_freeze(buf, 0);
272 nvecs = evbuffer_read_setup_vecs_(buf, at_most,
273 vecs, MAX_WSABUFS, &chainp, 1);
274 for (i=0;i<nvecs;++i) {
275 WSABUF_FROM_EVBUFFER_IOV(
280 buf_o->n_buffers = nvecs;
281 buf_o->first_pinned = chain = *chainp;
284 for ( ; chain; chain = chain->next) {
285 evbuffer_chain_pin_(chain, EVBUFFER_MEM_PINNED_R);
288 EVUTIL_ASSERT(npin == nvecs);
290 evbuffer_incref_(buf);
291 if (WSARecv(buf_o->fd, buf_o->buffers, nvecs, &bytesRead, &flags,
292 &ol->overlapped, NULL)) {
293 int error = WSAGetLastError();
294 if (error != WSA_IO_PENDING) {
295 /* An actual error. */
296 pin_release(buf_o, EVBUFFER_MEM_PINNED_R);
297 evbuffer_unfreeze(buf, 0);
298 evbuffer_free(buf); /* decref */
303 buf_o->read_in_progress = 1;
306 EVBUFFER_UNLOCK(buf);
311 evbuffer_overlapped_get_fd_(struct evbuffer *buf)
313 struct evbuffer_overlapped *buf_o = upcast_evbuffer(buf);
314 return buf_o ? buf_o->fd : -1;
318 evbuffer_overlapped_set_fd_(struct evbuffer *buf, evutil_socket_t fd)
320 struct evbuffer_overlapped *buf_o = upcast_evbuffer(buf);
322 /* XXX is this right?, should it cancel current I/O operations? */
325 EVBUFFER_UNLOCK(buf);