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 /*

  * Copyright (c) 2009-2012 Niels Provos and Nick Mathewson

  *

  * Redistribution and use in source and binary forms, with or without

  * modification, are permitted provided that the following conditions

  * are met:

  * 1. Redistributions of source code must retain the above copyright

  *    notice, this list of conditions and the following disclaimer.

  * 2. Redistributions in binary form must reproduce the above copyright

  *    notice, this list of conditions and the following disclaimer in the

  *    documentation and/or other materials provided with the distribution.

  * 3. The name of the author may not be used to endorse or promote products

  *    derived from this software without specific prior written permission.

  *

  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

  */

 /**

    @file buffer_iocp.c

    This module implements overlapped read and write functions for evbuffer

    objects on Windows.

 */

 #include "event2/buffer.h"

 #include "event2/buffer_compat.h"

 #include "event2/util.h"

 #include "event2/thread.h"

 #include "event2/event-config.h"

 #include "util-internal.h"

 #include "evthread-internal.h"

 #include "evbuffer-internal.h"

 #include "iocp-internal.h"

 #include "mm-internal.h"

 #include <winsock2.h>

 #include <windows.h>

 #include <stdio.h>

 #define MAX_WSABUFS 16

 /** An evbuffer that can handle overlapped IO. */

 struct evbuffer_overlapped {

 	struct evbuffer buffer;

 	/** The socket that we're doing overlapped IO on. */

 	evutil_socket_t fd;

 	/** pending I/O type */

 	unsigned read_in_progress : 1;

 	unsigned write_in_progress : 1;

 	/** The first pinned chain in the buffer. */

 	struct evbuffer_chain *first_pinned;

 	/** How many chains are pinned; how many of the fields in buffers

 	 * are we using. */

 	int n_buffers;

 	WSABUF buffers[MAX_WSABUFS];

 };

 /** Given an evbuffer, return the correponding evbuffer structure, or NULL if

  * the evbuffer isn't overlapped. */

 static inline struct evbuffer_overlapped *

 upcast_evbuffer(struct evbuffer *buf)

 {

 	if (!buf || !buf->is_overlapped)

 		return NULL;

 	return EVUTIL_UPCAST(buf, struct evbuffer_overlapped, buffer);

 }

 /** Unpin all the chains noted as pinned in 'eo'. */

 static void

 pin_release(struct evbuffer_overlapped *eo, unsigned flag)

 {

 	int i;

 	struct evbuffer_chain *next, *chain = eo->first_pinned;

 	for (i = 0; i < eo->n_buffers; ++i) {

 		EVUTIL_ASSERT(chain);

 		next = chain->next;

 		_evbuffer_chain_unpin(chain, flag);

 		chain = next;

 	}

 }

 void

 evbuffer_commit_read(struct evbuffer *evbuf, ev_ssize_t nBytes)

 {

 	struct evbuffer_overlapped *buf = upcast_evbuffer(evbuf);

 	struct evbuffer_chain **chainp;

 	size_t remaining, len;

 	unsigned i;

 	EVBUFFER_LOCK(evbuf);

 	EVUTIL_ASSERT(buf->read_in_progress && !buf->write_in_progress);

 	EVUTIL_ASSERT(nBytes >= 0); /* XXXX Can this be false? */

 	evbuffer_unfreeze(evbuf, 0);

 	chainp = evbuf->last_with_datap;

 	if (!((*chainp)->flags & EVBUFFER_MEM_PINNED_R))

 		chainp = &(*chainp)->next;

 	remaining = nBytes;

 	for (i = 0; remaining > 0 && i < (unsigned)buf->n_buffers; ++i) {

 		EVUTIL_ASSERT(*chainp);

 		len = buf->buffers[i].len;

 		if (remaining < len)

 			len = remaining;

 		(*chainp)->off += len;

 		evbuf->last_with_datap = chainp;

 		remaining -= len;

 		chainp = &(*chainp)->next;

 	}

 	pin_release(buf, EVBUFFER_MEM_PINNED_R);

 	buf->read_in_progress = 0;

 	evbuf->total_len += nBytes;

 	evbuf->n_add_for_cb += nBytes;

 	evbuffer_invoke_callbacks(evbuf);

 	_evbuffer_decref_and_unlock(evbuf);

 }

 void

 evbuffer_commit_write(struct evbuffer *evbuf, ev_ssize_t nBytes)

 {

 	struct evbuffer_overlapped *buf = upcast_evbuffer(evbuf);

 	EVBUFFER_LOCK(evbuf);

 	EVUTIL_ASSERT(buf->write_in_progress && !buf->read_in_progress);

 	evbuffer_unfreeze(evbuf, 1);

 	evbuffer_drain(evbuf, nBytes);

 	pin_release(buf,EVBUFFER_MEM_PINNED_W);

 	buf->write_in_progress = 0;

 	_evbuffer_decref_and_unlock(evbuf);

 }

 struct evbuffer *

 evbuffer_overlapped_new(evutil_socket_t fd)

 {

 	struct evbuffer_overlapped *evo;

 	evo = mm_calloc(1, sizeof(struct evbuffer_overlapped));

 	if (!evo)

 		return NULL;

 	TAILQ_INIT(&evo->buffer.callbacks);

 	evo->buffer.refcnt = 1;

 	evo->buffer.last_with_datap = &evo->buffer.first;

 	evo->buffer.is_overlapped = 1;

 	evo->fd = fd;

 	return &evo->buffer;

 }

 int

 evbuffer_launch_write(struct evbuffer *buf, ev_ssize_t at_most,

 		struct event_overlapped *ol)

 {

 	struct evbuffer_overlapped *buf_o = upcast_evbuffer(buf);

 	int r = -1;

 	int i;

 	struct evbuffer_chain *chain;

 	DWORD bytesSent;

 	if (!buf) {

 		/* No buffer, or it isn't overlapped */

 		return -1;

 	}

 	EVBUFFER_LOCK(buf);

 	EVUTIL_ASSERT(!buf_o->read_in_progress);

 	if (buf->freeze_start || buf_o->write_in_progress)

 		goto done;

 	if (!buf->total_len) {

 		/* Nothing to write */

 		r = 0;

 		goto done;

 	} else if (at_most < 0 || (size_t)at_most > buf->total_len) {

 		at_most = buf->total_len;

 	}

 	evbuffer_freeze(buf, 1);

 	buf_o->first_pinned = NULL;

 	buf_o->n_buffers = 0;

 	memset(buf_o->buffers, 0, sizeof(buf_o->buffers));

 	chain = buf_o->first_pinned = buf->first;

 	for (i=0; i < MAX_WSABUFS && chain; ++i, chain=chain->next) {

 		WSABUF *b = &buf_o->buffers[i];

 		b->buf = (char*)( chain->buffer + chain->misalign );

 		_evbuffer_chain_pin(chain, EVBUFFER_MEM_PINNED_W);

 		if ((size_t)at_most > chain->off) {

 			/* XXXX Cast is safe for now, since win32 has no

 			   mmaped chains.  But later, we need to have this

 			   add more WSAbufs if chain->off is greater than

 			   ULONG_MAX */

 			b->len = (unsigned long)chain->off;

 			at_most -= chain->off;

 		} else {

 			b->len = (unsigned long)at_most;

 			++i;

 			break;

 		}

 	}

 	buf_o->n_buffers = i;

 	_evbuffer_incref(buf);

 	if (WSASend(buf_o->fd, buf_o->buffers, i, &bytesSent, 0,

 		&ol->overlapped, NULL)) {

 		int error = WSAGetLastError();

 		if (error != WSA_IO_PENDING) {

 			/* An actual error. */

 			pin_release(buf_o, EVBUFFER_MEM_PINNED_W);

 			evbuffer_unfreeze(buf, 1);

 			evbuffer_free(buf); /* decref */

 			goto done;

 		}

 	}

 	buf_o->write_in_progress = 1;

 	r = 0;

 done:

 	EVBUFFER_UNLOCK(buf);

 	return r;

 }

 int

 evbuffer_launch_read(struct evbuffer *buf, size_t at_most,

 		struct event_overlapped *ol)

 {

 	struct evbuffer_overlapped *buf_o = upcast_evbuffer(buf);

 	int r = -1, i;

 	int nvecs;

 	int npin=0;

 	struct evbuffer_chain *chain=NULL, **chainp;

 	DWORD bytesRead;

 	DWORD flags = 0;

 	struct evbuffer_iovec vecs[MAX_WSABUFS];

 	if (!buf_o)

 		return -1;

 	EVBUFFER_LOCK(buf);

 	EVUTIL_ASSERT(!buf_o->write_in_progress);

 	if (buf->freeze_end || buf_o->read_in_progress)

 		goto done;

 	buf_o->first_pinned = NULL;

 	buf_o->n_buffers = 0;

 	memset(buf_o->buffers, 0, sizeof(buf_o->buffers));

 	if (_evbuffer_expand_fast(buf, at_most, MAX_WSABUFS) == -1)

 		goto done;

 	evbuffer_freeze(buf, 0);

 	nvecs = _evbuffer_read_setup_vecs(buf, at_most,

 	    vecs, MAX_WSABUFS, &chainp, 1);

 	for (i=0;i<nvecs;++i) {

 		WSABUF_FROM_EVBUFFER_IOV(

 			&buf_o->buffers[i],

 			&vecs[i]);

 	}

 	buf_o->n_buffers = nvecs;

 	buf_o->first_pinned = chain = *chainp;

 	npin=0;

 	for ( ; chain; chain = chain->next) {

 		_evbuffer_chain_pin(chain, EVBUFFER_MEM_PINNED_R);

 		++npin;

 	}

 	EVUTIL_ASSERT(npin == nvecs);

 	_evbuffer_incref(buf);

 	if (WSARecv(buf_o->fd, buf_o->buffers, nvecs, &bytesRead, &flags,

 		    &ol->overlapped, NULL)) {

 		int error = WSAGetLastError();

 		if (error != WSA_IO_PENDING) {

 			/* An actual error. */

 			pin_release(buf_o, EVBUFFER_MEM_PINNED_R);

 			evbuffer_unfreeze(buf, 0);

 			evbuffer_free(buf); /* decref */

 			goto done;

 		}

 	}

 	buf_o->read_in_progress = 1;

 	r = 0;

 done:

 	EVBUFFER_UNLOCK(buf);

 	return r;

 }

 evutil_socket_t

 _evbuffer_overlapped_get_fd(struct evbuffer *buf)

 {

 	struct evbuffer_overlapped *buf_o = upcast_evbuffer(buf);

 	return buf_o ? buf_o->fd : -1;

 }

 void

 _evbuffer_overlapped_set_fd(struct evbuffer *buf, evutil_socket_t fd)

 {

 	struct evbuffer_overlapped *buf_o = upcast_evbuffer(buf);

 	EVBUFFER_LOCK(buf);

 	/* XXX is this right?, should it cancel current I/O operations? */

 	if (buf_o)

 		buf_o->fd = fd;

 	EVBUFFER_UNLOCK(buf);

 }