* Copyright (c) 2002-2007 Niels Provos <provos@citi.umich.edu>

/* $NetBSD: buffer.c,v 1.7 2024/08/18 20:47:20 christos Exp $ */

/*
* Copyright (c) 2002-2007 Niels Provos <[email protected]>
* Copyright (c) 2007-2012 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.
*/

#include "event2/event-config.h"
#include "evconfig-private.h"

#ifdef _WIN32
#include <winsock2.h>
#include <windows.h>
#include <io.h>
#endif

#ifdef EVENT__HAVE_VASPRINTF
/* If we have vasprintf, we need to define _GNU_SOURCE before we include
* stdio.h. This comes from evconfig-private.h.
*/
#endif

#include <sys/types.h>

#ifdef EVENT__HAVE_SYS_TIME_H
#include <sys/time.h>
#endif

#ifdef EVENT__HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif

#ifdef EVENT__HAVE_SYS_UIO_H
#include <sys/uio.h>
#endif

#ifdef EVENT__HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif

#ifdef EVENT__HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif

#ifdef EVENT__HAVE_SYS_SENDFILE_H
#include <sys/sendfile.h>
#endif
#ifdef EVENT__HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef EVENT__HAVE_STDARG_H
#include <stdarg.h>
#endif
#ifdef EVENT__HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <limits.h>

#include "event2/event.h"
#include "event2/buffer.h"
#include "event2/buffer_compat.h"
#include "event2/bufferevent.h"
#include "event2/bufferevent_compat.h"
#include "event2/bufferevent_struct.h"
#include "event2/thread.h"
#include "log-internal.h"
#include "mm-internal.h"
#include "util-internal.h"
#include "evthread-internal.h"
#include "evbuffer-internal.h"
#include "bufferevent-internal.h"
#include "event-internal.h"

/* some systems do not have MAP_FAILED */
#ifndef MAP_FAILED
#define MAP_FAILED ((void *)-1)
#endif

/* send file support */
#if defined(EVENT__HAVE_SYS_SENDFILE_H) && defined(EVENT__HAVE_SENDFILE) && defined(__linux__)
#define USE_SENDFILE 1
#define SENDFILE_IS_LINUX 1
#elif defined(EVENT__HAVE_SENDFILE) && defined(__FreeBSD__)
#define USE_SENDFILE 1
#define SENDFILE_IS_FREEBSD 1
#elif defined(EVENT__HAVE_SENDFILE) && defined(__APPLE__)
#define USE_SENDFILE 1
#define SENDFILE_IS_MACOSX 1
#elif defined(EVENT__HAVE_SENDFILE) && defined(__sun__) && defined(__svr4__)
#define USE_SENDFILE 1
#define SENDFILE_IS_SOLARIS 1
#endif

/* Mask of user-selectable callback flags. */
#define EVBUFFER_CB_USER_FLAGS 0xffff
/* Mask of all internal-use-only flags. */
#define EVBUFFER_CB_INTERNAL_FLAGS 0xffff0000

/* Flag set if the callback is using the cb_obsolete function pointer */
#define EVBUFFER_CB_OBSOLETE 0x00040000

/* evbuffer_chain support */
#define CHAIN_SPACE_PTR(ch) ((ch)->buffer + (ch)->misalign + (ch)->off)
#define CHAIN_SPACE_LEN(ch) ((ch)->flags & EVBUFFER_IMMUTABLE ? \
0 : (ch)->buffer_len - ((ch)->misalign + (ch)->off))

#define CHAIN_PINNED(ch) (((ch)->flags & EVBUFFER_MEM_PINNED_ANY) != 0)
#define CHAIN_PINNED_R(ch) (((ch)->flags & EVBUFFER_MEM_PINNED_R) != 0)

/* evbuffer_ptr support */
#define PTR_NOT_FOUND(ptr) do { \
(ptr)->pos = -1; \
(ptr)->internal_.chain = NULL; \
(ptr)->internal_.pos_in_chain = 0; \
} while (0)

static void evbuffer_chain_align(struct evbuffer_chain *chain);
static int evbuffer_chain_should_realign(struct evbuffer_chain *chain,
size_t datalen);
static void evbuffer_deferred_callback(struct event_callback *cb, void *arg);
static int evbuffer_ptr_memcmp(const struct evbuffer *buf,
const struct evbuffer_ptr *pos, const char *mem, size_t len);
static struct evbuffer_chain *evbuffer_expand_singlechain(struct evbuffer *buf,
size_t datlen);
static int evbuffer_ptr_subtract(struct evbuffer *buf, struct evbuffer_ptr *pos,
size_t howfar);
static int evbuffer_file_segment_materialize(struct evbuffer_file_segment *seg);
static inline void evbuffer_chain_incref(struct evbuffer_chain *chain);

static struct evbuffer_chain *
evbuffer_chain_new(size_t size)
{
struct evbuffer_chain *chain;
size_t to_alloc;

if (size > EVBUFFER_CHAIN_MAX - EVBUFFER_CHAIN_SIZE)
return (NULL);

size += EVBUFFER_CHAIN_SIZE;

/* get the next largest memory that can hold the buffer */
if (size < EVBUFFER_CHAIN_MAX / 2) {
to_alloc = MIN_BUFFER_SIZE;
while (to_alloc < size) {
to_alloc <<= 1;
}
} else {
to_alloc = size;
}

/* we get everything in one chunk */
if ((chain = mm_malloc(to_alloc)) == NULL)
return (NULL);

memset(chain, 0, EVBUFFER_CHAIN_SIZE);

chain->buffer_len = to_alloc - EVBUFFER_CHAIN_SIZE;

/* this way we can manipulate the buffer to different addresses,
* which is required for mmap for example.
*/
chain->buffer = EVBUFFER_CHAIN_EXTRA(unsigned char, chain);

chain->refcnt = 1;

return (chain);
}

static inline void
evbuffer_chain_free(struct evbuffer_chain *chain)
{
EVUTIL_ASSERT(chain->refcnt > 0);
if (--chain->refcnt > 0) {
/* chain is still referenced by other chains */
return;
}

if (CHAIN_PINNED(chain)) {
/* will get freed once no longer dangling */
chain->refcnt++;
chain->flags |= EVBUFFER_DANGLING;
return;
}

/* safe to release chain, it's either a referencing
* chain or all references to it have been freed */
if (chain->flags & EVBUFFER_REFERENCE) {
struct evbuffer_chain_reference *info =
EVBUFFER_CHAIN_EXTRA(
struct evbuffer_chain_reference,
chain);
if (info->cleanupfn)
(*info->cleanupfn)(chain->buffer,
chain->buffer_len,
info->extra);
}
if (chain->flags & EVBUFFER_FILESEGMENT) {
struct evbuffer_chain_file_segment *info =
EVBUFFER_CHAIN_EXTRA(
struct evbuffer_chain_file_segment,
chain);
if (info->segment) {
#ifdef _WIN32
if (info->segment->is_mapping)
UnmapViewOfFile(chain->buffer);
#endif
evbuffer_file_segment_free(info->segment);
}
}
if (chain->flags & EVBUFFER_MULTICAST) {
struct evbuffer_multicast_parent *info =
EVBUFFER_CHAIN_EXTRA(
struct evbuffer_multicast_parent,
chain);
/* referencing chain is being freed, decrease
* refcounts of source chain and associated
* evbuffer (which get freed once both reach
* zero) */
EVUTIL_ASSERT(info->source != NULL);
EVUTIL_ASSERT(info->parent != NULL);
EVBUFFER_LOCK(info->source);
evbuffer_chain_free(info->parent);
evbuffer_decref_and_unlock_(info->source);
}

mm_free(chain);
}

static void
evbuffer_free_all_chains(struct evbuffer_chain *chain)
{
struct evbuffer_chain *next;
for (; chain; chain = next) {
next = chain->next;
evbuffer_chain_free(chain);
}
}

#ifndef NDEBUG
static int
evbuffer_chains_all_empty(struct evbuffer_chain *chain)
{
for (; chain; chain = chain->next) {
if (chain->off)
return 0;
}
return 1;
}
#else
/* The definition is needed for EVUTIL_ASSERT, which uses sizeof to avoid
"unused variable" warnings. */
static inline int evbuffer_chains_all_empty(struct evbuffer_chain *chain) {
return 1;
}
#endif

/* Free all trailing chains in 'buf' that are neither pinned nor empty, prior
* to replacing them all with a new chain. Return a pointer to the place
* where the new chain will go.
*
* Internal; requires lock. The caller must fix up buf->last and buf->first
* as needed; they might have been freed.
*/
static struct evbuffer_chain **
evbuffer_free_trailing_empty_chains(struct evbuffer *buf)
{
struct evbuffer_chain **ch = buf->last_with_datap;
/* Find the first victim chain. It might be *last_with_datap */
while ((*ch) && ((*ch)->off != 0 || CHAIN_PINNED(*ch)))
ch = &(*ch)->next;
if (*ch) {
EVUTIL_ASSERT(evbuffer_chains_all_empty(*ch));
evbuffer_free_all_chains(*ch);
*ch = NULL;
}
return ch;
}

/* Add a single chain 'chain' to the end of 'buf', freeing trailing empty
* chains as necessary. Requires lock. Does not schedule callbacks.
*/
static void
evbuffer_chain_insert(struct evbuffer *buf,
struct evbuffer_chain *chain)
{
ASSERT_EVBUFFER_LOCKED(buf);
if (*buf->last_with_datap == NULL) {
/* There are no chains data on the buffer at all. */
EVUTIL_ASSERT(buf->last_with_datap == &buf->first);
EVUTIL_ASSERT(buf->first == NULL);
buf->first = buf->last = chain;
} else {
struct evbuffer_chain **chp;
chp = evbuffer_free_trailing_empty_chains(buf);
*chp = chain;
if (chain->off)
buf->last_with_datap = chp;
buf->last = chain;
}
buf->total_len += chain->off;
}

static inline struct evbuffer_chain *
evbuffer_chain_insert_new(struct evbuffer *buf, size_t datlen)
{
struct evbuffer_chain *chain;
if ((chain = evbuffer_chain_new(datlen)) == NULL)
return NULL;
evbuffer_chain_insert(buf, chain);
return chain;
}

void
evbuffer_chain_pin_(struct evbuffer_chain *chain, unsigned flag)
{
EVUTIL_ASSERT((chain->flags & flag) == 0);
chain->flags |= flag;
}

void
evbuffer_chain_unpin_(struct evbuffer_chain *chain, unsigned flag)
{
EVUTIL_ASSERT((chain->flags & flag) != 0);
chain->flags &= ~flag;
if (chain->flags & EVBUFFER_DANGLING)
evbuffer_chain_free(chain);
}

static inline void
evbuffer_chain_incref(struct evbuffer_chain *chain)
{
++chain->refcnt;
}

struct evbuffer *
evbuffer_new(void)
{
struct evbuffer *buffer;

buffer = mm_calloc(1, sizeof(struct evbuffer));
if (buffer == NULL)
return (NULL);

LIST_INIT(&buffer->callbacks);
buffer->refcnt = 1;
buffer->last_with_datap = &buffer->first;

return (buffer);
}

int
evbuffer_set_flags(struct evbuffer *buf, ev_uint64_t flags)
{
EVBUFFER_LOCK(buf);
buf->flags |= (ev_uint32_t)flags;
EVBUFFER_UNLOCK(buf);
return 0;
}

int
evbuffer_clear_flags(struct evbuffer *buf, ev_uint64_t flags)
{
EVBUFFER_LOCK(buf);
buf->flags &= ~(ev_uint32_t)flags;
EVBUFFER_UNLOCK(buf);
return 0;
}

void
evbuffer_incref_(struct evbuffer *buf)
{
EVBUFFER_LOCK(buf);
++buf->refcnt;
EVBUFFER_UNLOCK(buf);
}

void
evbuffer_incref_and_lock_(struct evbuffer *buf)
{
EVBUFFER_LOCK(buf);
++buf->refcnt;
}

int
evbuffer_defer_callbacks(struct evbuffer *buffer, struct event_base *base)
{
EVBUFFER_LOCK(buffer);
buffer->cb_queue = base;
buffer->deferred_cbs = 1;
event_deferred_cb_init_(&buffer->deferred,
event_base_get_npriorities(base) / 2,
evbuffer_deferred_callback, buffer);
EVBUFFER_UNLOCK(buffer);
return 0;
}

int
evbuffer_enable_locking(struct evbuffer *buf, void *lock)
{
#ifdef EVENT__DISABLE_THREAD_SUPPORT
return -1;
#else
if (buf->lock)
return -1;

if (!lock) {
EVTHREAD_ALLOC_LOCK(lock, EVTHREAD_LOCKTYPE_RECURSIVE);
if (!lock)
return -1;
buf->lock = lock;
buf->own_lock = 1;
} else {
buf->lock = lock;
buf->own_lock = 0;
}

return 0;
#endif
}

void
evbuffer_set_parent_(struct evbuffer *buf, struct bufferevent *bev)
{
EVBUFFER_LOCK(buf);
buf->parent = bev;
EVBUFFER_UNLOCK(buf);
}

static void
evbuffer_run_callbacks(struct evbuffer *buffer, int running_deferred)
{
struct evbuffer_cb_entry *cbent, *next;
struct evbuffer_cb_info info;
size_t new_size;
ev_uint32_t mask, masked_val;
int clear = 1;

if (running_deferred) {
mask = EVBUFFER_CB_NODEFER|EVBUFFER_CB_ENABLED;
masked_val = EVBUFFER_CB_ENABLED;
} else if (buffer->deferred_cbs) {
mask = EVBUFFER_CB_NODEFER|EVBUFFER_CB_ENABLED;
masked_val = EVBUFFER_CB_NODEFER|EVBUFFER_CB_ENABLED;
/* Don't zero-out n_add/n_del, since the deferred callbacks
will want to see them. */
clear = 0;
} else {
mask = EVBUFFER_CB_ENABLED;
masked_val = EVBUFFER_CB_ENABLED;
}

ASSERT_EVBUFFER_LOCKED(buffer);

if (LIST_EMPTY(&buffer->callbacks)) {
buffer->n_add_for_cb = buffer->n_del_for_cb = 0;
return;
}
if (buffer->n_add_for_cb == 0 && buffer->n_del_for_cb == 0)
return;

new_size = buffer->total_len;
info.orig_size = new_size + buffer->n_del_for_cb - buffer->n_add_for_cb;
info.n_added = buffer->n_add_for_cb;
info.n_deleted = buffer->n_del_for_cb;
if (clear) {
buffer->n_add_for_cb = 0;
buffer->n_del_for_cb = 0;
}
for (cbent = LIST_FIRST(&buffer->callbacks);
cbent != LIST_END(&buffer->callbacks);
cbent = next) {
/* Get the 'next' pointer now in case this callback decides
* to remove itself or something. */
next = LIST_NEXT(cbent, next);

if ((cbent->flags & mask) != masked_val)
continue;

if ((cbent->flags & EVBUFFER_CB_OBSOLETE))
cbent->cb.cb_obsolete(buffer,
info.orig_size, new_size, cbent->cbarg);
else
cbent->cb.cb_func(buffer, &info, cbent->cbarg);
}
}

void
evbuffer_invoke_callbacks_(struct evbuffer *buffer)
{
if (LIST_EMPTY(&buffer->callbacks)) {
buffer->n_add_for_cb = buffer->n_del_for_cb = 0;
return;
}

if (buffer->deferred_cbs) {
if (event_deferred_cb_schedule_(buffer->cb_queue, &buffer->deferred)) {
evbuffer_incref_and_lock_(buffer);
if (buffer->parent)
bufferevent_incref_(buffer->parent);
EVBUFFER_UNLOCK(buffer);
}
}

evbuffer_run_callbacks(buffer, 0);
}

static void
evbuffer_deferred_callback(struct event_callback *cb, void *arg)
{
struct bufferevent *parent = NULL;
struct evbuffer *buffer = arg;

/* XXXX It would be better to run these callbacks without holding the
* lock */
EVBUFFER_LOCK(buffer);
parent = buffer->parent;
evbuffer_run_callbacks(buffer, 1);
evbuffer_decref_and_unlock_(buffer);
if (parent)
bufferevent_decref_(parent);
}

static void
evbuffer_remove_all_callbacks(struct evbuffer *buffer)
{
struct evbuffer_cb_entry *cbent;

while ((cbent = LIST_FIRST(&buffer->callbacks))) {
LIST_REMOVE(cbent, next);
mm_free(cbent);
}
}

void
evbuffer_decref_and_unlock_(struct evbuffer *buffer)
{
struct evbuffer_chain *chain, *next;
ASSERT_EVBUFFER_LOCKED(buffer);

EVUTIL_ASSERT(buffer->refcnt > 0);

if (--buffer->refcnt > 0) {
EVBUFFER_UNLOCK(buffer);
return;
}

for (chain = buffer->first; chain != NULL; chain = next) {
next = chain->next;
evbuffer_chain_free(chain);
}
evbuffer_remove_all_callbacks(buffer);
if (buffer->deferred_cbs)
event_deferred_cb_cancel_(buffer->cb_queue, &buffer->deferred);

EVBUFFER_UNLOCK(buffer);
if (buffer->own_lock)
EVTHREAD_FREE_LOCK(buffer->lock, EVTHREAD_LOCKTYPE_RECURSIVE);
mm_free(buffer);
}

void
evbuffer_free(struct evbuffer *buffer)
{
EVBUFFER_LOCK(buffer);
evbuffer_decref_and_unlock_(buffer);
}

void
evbuffer_lock(struct evbuffer *buf)
{
EVBUFFER_LOCK(buf);
}

void
evbuffer_unlock(struct evbuffer *buf)
{
EVBUFFER_UNLOCK(buf);
}

size_t
evbuffer_get_length(const struct evbuffer *buffer)
{
size_t result;

EVBUFFER_LOCK(buffer);

result = (buffer->total_len);

EVBUFFER_UNLOCK(buffer);

return result;
}

size_t
evbuffer_get_contiguous_space(const struct evbuffer *buf)
{
struct evbuffer_chain *chain;
size_t result;

EVBUFFER_LOCK(buf);
chain = buf->first;
result = (chain != NULL ? chain->off : 0);
EVBUFFER_UNLOCK(buf);

return result;
}

size_t
evbuffer_add_iovec(struct evbuffer * buf, struct evbuffer_iovec * vec, int n_vec) {
int n;
size_t res;
size_t to_alloc;

EVBUFFER_LOCK(buf);

res = to_alloc = 0;

for (n = 0; n < n_vec; n++) {
to_alloc += vec[n].iov_len;
}

if (evbuffer_expand_fast_(buf, to_alloc, 2) < 0) {
goto done;
}

for (n = 0; n < n_vec; n++) {
/* XXX each 'add' call here does a bunch of setup that's
* obviated by evbuffer_expand_fast_, and some cleanup that we
* would like to do only once. Instead we should just extract
* the part of the code that's needed. */

if (evbuffer_add(buf, vec[n].iov_base, vec[n].iov_len) < 0) {
goto done;
}

res += vec[n].iov_len;
}

done:
EVBUFFER_UNLOCK(buf);
return res;
}

int
evbuffer_reserve_space(struct evbuffer *buf, ev_ssize_t size,
struct evbuffer_iovec *vec, int n_vecs)
{
struct evbuffer_chain *chain, **chainp;
int n = -1;

EVBUFFER_LOCK(buf);
if (buf->freeze_end)
goto done;
if (n_vecs < 1)
goto done;
if (n_vecs == 1) {
if ((chain = evbuffer_expand_singlechain(buf, size)) == NULL)
goto done;

vec[0].iov_base = (void *)CHAIN_SPACE_PTR(chain);
vec[0].iov_len = (size_t)CHAIN_SPACE_LEN(chain);
EVUTIL_ASSERT(size<0 || (size_t)vec[0].iov_len >= (size_t)size);
n = 1;
} else {
if (evbuffer_expand_fast_(buf, size, n_vecs)<0)
goto done;
n = evbuffer_read_setup_vecs_(buf, size, vec, n_vecs,
&chainp, 0);
}

done:
EVBUFFER_UNLOCK(buf);
return n;

}

static int
advance_last_with_data(struct evbuffer *buf)
{
int n = 0;
struct evbuffer_chain **chainp = buf->last_with_datap;

ASSERT_EVBUFFER_LOCKED(buf);

if (!*chainp)
return 0;

while ((*chainp)->next) {
chainp = &(*chainp)->next;
if ((*chainp)->off)
buf->last_with_datap = chainp;
++n;
}
return n;
}

int
evbuffer_commit_space(struct evbuffer *buf,
struct evbuffer_iovec *vec, int n_vecs)
{
struct evbuffer_chain *chain, **firstchainp, **chainp;
int result = -1;
size_t added = 0;
int i;

EVBUFFER_LOCK(buf);

if (buf->freeze_end)
goto done;
if (n_vecs == 0) {
result = 0;
goto done;
} else if (n_vecs == 1 &&
(buf->last && vec[0].iov_base == (void *)CHAIN_SPACE_PTR(buf->last))) {
/* The user only got or used one chain; it might not
* be the first one with space in it. */
if ((size_t)vec[0].iov_len > (size_t)CHAIN_SPACE_LEN(buf->last))
goto done;
buf->last->off += vec[0].iov_len;
added = vec[0].iov_len;
if (added)
advance_last_with_data(buf);
goto okay;
}

/* Advance 'firstchain' to the first chain with space in it. */
firstchainp = buf->last_with_datap;
if (!*firstchainp)
goto done;
if (CHAIN_SPACE_LEN(*firstchainp) == 0) {
firstchainp = &(*firstchainp)->next;
}

chain = *firstchainp;
/* pass 1: make sure that the pointers and lengths of vecs[] are in
* bounds before we try to commit anything. */
for (i=0; i<n_vecs; ++i) {
if (!chain)
goto done;
if (vec[i].iov_base != (void *)CHAIN_SPACE_PTR(chain) ||
(size_t)vec[i].iov_len > CHAIN_SPACE_LEN(chain))
goto done;
chain = chain->next;
}
/* pass 2: actually adjust all the chains. */
chainp = firstchainp;
for (i=0; i<n_vecs; ++i) {
(*chainp)->off += vec[i].iov_len;
added += vec[i].iov_len;
if (vec[i].iov_len) {
buf->last_with_datap = chainp;
}
chainp = &(*chainp)->next;
}

okay:
buf->total_len += added;
buf->n_add_for_cb += added;
result = 0;
evbuffer_invoke_callbacks_(buf);

done:
EVBUFFER_UNLOCK(buf);
return result;
}

static inline int
HAS_PINNED_R(struct evbuffer *buf)
{
return (buf->last && CHAIN_PINNED_R(buf->last));
}

static inline void
ZERO_CHAIN(struct evbuffer *dst)
{
ASSERT_EVBUFFER_LOCKED(dst);
dst->first = NULL;
dst->last = NULL;
dst->last_with_datap = &(dst)->first;
dst->total_len = 0;
}

/* Prepares the contents of src to be moved to another buffer by removing
* read-pinned chains. The first pinned chain is saved in first, and the
* last in last. If src has no read-pinned chains, first and last are set
* to NULL. */
static int
PRESERVE_PINNED(struct evbuffer *src, struct evbuffer_chain **first,
struct evbuffer_chain **last)
{
struct evbuffer_chain *chain, **pinned;

ASSERT_EVBUFFER_LOCKED(src);

if (!HAS_PINNED_R(src)) {
*first = *last = NULL;
return 0;
}

pinned = src->last_with_datap;
if (!CHAIN_PINNED_R(*pinned))
pinned = &(*pinned)->next;
EVUTIL_ASSERT(CHAIN_PINNED_R(*pinned));
chain = *first = *pinned;
*last = src->last;

/* If there's data in the first pinned chain, we need to allocate
* a new chain and copy the data over. */
if (chain->off) {
struct evbuffer_chain *tmp;

EVUTIL_ASSERT(pinned == src->last_with_datap);
tmp = evbuffer_chain_new(chain->off);
if (!tmp)
return -1;
memcpy(tmp->buffer, chain->buffer + chain->misalign,
chain->off);
tmp->off = chain->off;
*src->last_with_datap = tmp;
src->last = tmp;
chain->misalign += chain->off;
chain->off = 0;
} else {
src->last = *src->last_with_datap;
*pinned = NULL;
}

return 0;
}

static inline void
RESTORE_PINNED(struct evbuffer *src, struct evbuffer_chain *pinned,
struct evbuffer_chain *last)
{
ASSERT_EVBUFFER_LOCKED(src);

if (!pinned) {
ZERO_CHAIN(src);
return;
}

src->first = pinned;
src->last = last;
src->last_with_datap = &src->first;
src->total_len = 0;
}

static inline void
COPY_CHAIN(struct evbuffer *dst, struct evbuffer *src)
{
ASSERT_EVBUFFER_LOCKED(dst);
ASSERT_EVBUFFER_LOCKED(src);
dst->first = src->first;
if (src->last_with_datap == &src->first)
dst->last_with_datap = &dst->first;
else
dst->last_with_datap = src->last_with_datap;
dst->last = src->last;
dst->total_len = src->total_len;
}

static void
APPEND_CHAIN(struct evbuffer *dst, struct evbuffer *src)
{
struct evbuffer_chain **chp;

ASSERT_EVBUFFER_LOCKED(dst);
ASSERT_EVBUFFER_LOCKED(src);

chp = evbuffer_free_trailing_empty_chains(dst);
*chp = src->first;

if (src->last_with_datap == &src->first)
dst->last_with_datap = chp;
else
dst->last_with_datap = src->last_with_datap;
dst->last = src->last;
dst->total_len += src->total_len;
}

static inline void
APPEND_CHAIN_MULTICAST(struct evbuffer *dst, struct evbuffer *src)
{
struct evbuffer_chain *tmp;
struct evbuffer_chain *chain = src->first;
struct evbuffer_multicast_parent *extra;

ASSERT_EVBUFFER_LOCKED(dst);
ASSERT_EVBUFFER_LOCKED(src);

for (; chain; chain = chain->next) {
if (!chain->off || chain->flags & EVBUFFER_DANGLING) {
/* skip empty chains */
continue;
}

tmp = evbuffer_chain_new(sizeof(struct evbuffer_multicast_parent));
if (!tmp) {
event_warn("%s: out of memory", __func__);
return;
}
extra = EVBUFFER_CHAIN_EXTRA(struct evbuffer_multicast_parent, tmp);
/* reference evbuffer containing source chain so it
* doesn't get released while the chain is still
* being referenced to */
evbuffer_incref_(src);
extra->source = src;
/* reference source chain which now becomes immutable */
evbuffer_chain_incref(chain);
extra->parent = chain;
chain->flags |= EVBUFFER_IMMUTABLE;
tmp->buffer_len = chain->buffer_len;
tmp->misalign = chain->misalign;
tmp->off = chain->off;
tmp->flags |= EVBUFFER_MULTICAST|EVBUFFER_IMMUTABLE;
tmp->buffer = chain->buffer;
evbuffer_chain_insert(dst, tmp);
}
}

static void
PREPEND_CHAIN(struct evbuffer *dst, struct evbuffer *src)
{
ASSERT_EVBUFFER_LOCKED(dst);
ASSERT_EVBUFFER_LOCKED(src);
src->last->next = dst->first;
dst->first = src->first;
dst->total_len += src->total_len;
if (*dst->last_with_datap == NULL) {
if (src->last_with_datap == &(src)->first)
dst->last_with_datap = &dst->first;
else
dst->last_with_datap = src->last_with_datap;
} else if (dst->last_with_datap == &dst->first) {
dst->last_with_datap = &src->last->next;
}
}

int
evbuffer_add_buffer(struct evbuffer *outbuf, struct evbuffer *inbuf)
{
struct evbuffer_chain *pinned, *last;
size_t in_total_len, out_total_len;
int result = 0;

EVBUFFER_LOCK2(inbuf, outbuf);
in_total_len = inbuf->total_len;
out_total_len = outbuf->total_len;

if (in_total_len == 0 || outbuf == inbuf)
goto done;

if (outbuf->freeze_end || inbuf->freeze_start) {
result = -1;
goto done;
}

if (PRESERVE_PINNED(inbuf, &pinned, &last) < 0) {
result = -1;
goto done;
}

if (out_total_len == 0) {
/* There might be an empty chain at the start of outbuf; free
* it. */
evbuffer_free_all_chains(outbuf->first);
COPY_CHAIN(outbuf, inbuf);
} else {
APPEND_CHAIN(outbuf, inbuf);
}

RESTORE_PINNED(inbuf, pinned, last);

inbuf->n_del_for_cb += in_total_len;
outbuf->n_add_for_cb += in_total_len;

evbuffer_invoke_callbacks_(inbuf);
evbuffer_invoke_callbacks_(outbuf);

done:
EVBUFFER_UNLOCK2(inbuf, outbuf);
return result;
}

int
evbuffer_add_buffer_reference(struct evbuffer *outbuf, struct evbuffer *inbuf)
{
size_t in_total_len, out_total_len;
struct evbuffer_chain *chain;
int result = 0;

EVBUFFER_LOCK2(inbuf, outbuf);
in_total_len = inbuf->total_len;
out_total_len = outbuf->total_len;
chain = inbuf->first;

if (in_total_len == 0)
goto done;

if (outbuf->freeze_end || outbuf == inbuf) {
result = -1;
goto done;
}

for (; chain; chain = chain->next) {
if ((chain->flags & (EVBUFFER_FILESEGMENT|EVBUFFER_SENDFILE|EVBUFFER_MULTICAST)) != 0) {
/* chain type can not be referenced */
result = -1;
goto done;
}
}

if (out_total_len == 0) {
/* There might be an empty chain at the start of outbuf; free
* it. */
evbuffer_free_all_chains(outbuf->first);
}
APPEND_CHAIN_MULTICAST(outbuf, inbuf);

outbuf->n_add_for_cb += in_total_len;
evbuffer_invoke_callbacks_(outbuf);

done:
EVBUFFER_UNLOCK2(inbuf, outbuf);
return result;
}

int
evbuffer_prepend_buffer(struct evbuffer *outbuf, struct evbuffer *inbuf)
{
struct evbuffer_chain *pinned, *last;
size_t in_total_len, out_total_len;
int result = 0;

EVBUFFER_LOCK2(inbuf, outbuf);

in_total_len = inbuf->total_len;
out_total_len = outbuf->total_len;

if (!in_total_len || inbuf == outbuf)
goto done;

if (outbuf->freeze_start || inbuf->freeze_start) {
result = -1;
goto done;
}

if (PRESERVE_PINNED(inbuf, &pinned, &last) < 0) {
result = -1;
goto done;
}

if (out_total_len == 0) {
/* There might be an empty chain at the start of outbuf; free
* it. */
evbuffer_free_all_chains(outbuf->first);
COPY_CHAIN(outbuf, inbuf);
} else {
PREPEND_CHAIN(outbuf, inbuf);
}

RESTORE_PINNED(inbuf, pinned, last);

inbuf->n_del_for_cb += in_total_len;
outbuf->n_add_for_cb += in_total_len;

evbuffer_invoke_callbacks_(inbuf);
evbuffer_invoke_callbacks_(outbuf);
done:
EVBUFFER_UNLOCK2(inbuf, outbuf);
return result;
}

int
evbuffer_drain(struct evbuffer *buf, size_t len)
{
struct evbuffer_chain *chain, *next;
size_t remaining, old_len;
int result = 0;

EVBUFFER_LOCK(buf);
old_len = buf->total_len;

if (old_len == 0)
goto done;

if (buf->freeze_start) {
result = -1;
goto done;
}

if (len >= old_len && !HAS_PINNED_R(buf)) {
len = old_len;
for (chain = buf->first; chain != NULL; chain = next) {
next = chain->next;
evbuffer_chain_free(chain);
}

ZERO_CHAIN(buf);
} else {
if (len >= old_len)
len = old_len;

buf->total_len -= len;
remaining = len;
for (chain = buf->first;
remaining >= chain->off;
chain = next) {
next = chain->next;
remaining -= chain->off;

if (chain == *buf->last_with_datap) {
buf->last_with_datap = &buf->first;
}
if (&chain->next == buf->last_with_datap)
buf->last_with_datap = &buf->first;

if (CHAIN_PINNED_R(chain)) {
EVUTIL_ASSERT(remaining == 0);
chain->misalign += chain->off;
chain->off = 0;
break;
} else
evbuffer_chain_free(chain);
}

buf->first = chain;
EVUTIL_ASSERT(remaining <= chain->off);
chain->misalign += remaining;
chain->off -= remaining;
}

buf->n_del_for_cb += len;
/* Tell someone about changes in this buffer */
evbuffer_invoke_callbacks_(buf);

done:
EVBUFFER_UNLOCK(buf);
return result;
}

/* Reads data from an event buffer and drains the bytes read */
int
evbuffer_remove(struct evbuffer *buf, void *data_out, size_t datlen)
{
ev_ssize_t n;
EVBUFFER_LOCK(buf);
n = evbuffer_copyout_from(buf, NULL, data_out, datlen);
if (n > 0) {
if (evbuffer_drain(buf, n)<0)
n = -1;
}
EVBUFFER_UNLOCK(buf);
return (int)n;
}

ev_ssize_t
evbuffer_copyout(struct evbuffer *buf, void *data_out, size_t datlen)
{
return evbuffer_copyout_from(buf, NULL, data_out, datlen);
}

ev_ssize_t
evbuffer_copyout_from(struct evbuffer *buf, const struct evbuffer_ptr *pos,
void *data_out, size_t datlen)
{
/*XXX fails badly on sendfile case. */
struct evbuffer_chain *chain;
char *data = data_out;
size_t nread;
ev_ssize_t result = 0;
size_t pos_in_chain;

EVBUFFER_LOCK(buf);

if (pos) {
if (datlen > (size_t)(EV_SSIZE_MAX - pos->pos)) {
result = -1;
goto done;
}
chain = pos->internal_.chain;
pos_in_chain = pos->internal_.pos_in_chain;
if (datlen + pos->pos > buf->total_len)
datlen = buf->total_len - pos->pos;
} else {
chain = buf->first;
pos_in_chain = 0;
if (datlen > buf->total_len)
datlen = buf->total_len;
}

if (datlen == 0)
goto done;

if (buf->freeze_start) {
result = -1;
goto done;
}

nread = datlen;

while (datlen && datlen >= chain->off - pos_in_chain) {
size_t copylen = chain->off - pos_in_chain;
memcpy(data,
chain->buffer + chain->misalign + pos_in_chain,
copylen);
data += copylen;
datlen -= copylen;

chain = chain->next;
pos_in_chain = 0;
EVUTIL_ASSERT(chain || datlen==0);
}

if (datlen) {
EVUTIL_ASSERT(chain);
EVUTIL_ASSERT(datlen+pos_in_chain <= chain->off);

memcpy(data, chain->buffer + chain->misalign + pos_in_chain,
datlen);
}

result = nread;
done:
EVBUFFER_UNLOCK(buf);
return result;
}

/* reads data from the src buffer to the dst buffer, avoids memcpy as
* possible. */
/* XXXX should return ev_ssize_t */
int
evbuffer_remove_buffer(struct evbuffer *src, struct evbuffer *dst,
size_t datlen)
{
/*XXX We should have an option to force this to be zero-copy.*/

/*XXX can fail badly on sendfile case. */
struct evbuffer_chain *chain, *previous;
size_t nread = 0;
int result;

EVBUFFER_LOCK2(src, dst);

chain = previous = src->first;

if (datlen == 0 || dst == src) {
result = 0;
goto done;
}

if (dst->freeze_end || src->freeze_start) {
result = -1;
goto done;
}

/* short-cut if there is no more data buffered */
if (datlen >= src->total_len) {
datlen = src->total_len;
evbuffer_add_buffer(dst, src);
result = (int)datlen; /*XXXX should return ev_ssize_t*/
goto done;
}

/* removes chains if possible */
while (chain->off <= datlen) {
/* We can't remove the last with data from src unless we
* remove all chains, in which case we would have done the if
* block above */
EVUTIL_ASSERT(chain != *src->last_with_datap);
nread += chain->off;
datlen -= chain->off;
previous = chain;
if (src->last_with_datap == &chain->next)
src->last_with_datap = &src->first;
chain = chain->next;
}

if (chain != src->first) {
/* we can remove the chain */
struct evbuffer_chain **chp;
chp = evbuffer_free_trailing_empty_chains(dst);

if (dst->first == NULL) {
dst->first = src->first;
} else {
*chp = src->first;
}
dst->last = previous;
previous->next = NULL;
src->first = chain;
advance_last_with_data(dst);

dst->total_len += nread;
dst->n_add_for_cb += nread;
}

/* we know that there is more data in the src buffer than
* we want to read, so we manually drain the chain */
evbuffer_add(dst, chain->buffer + chain->misalign, datlen);
chain->misalign += datlen;
chain->off -= datlen;
nread += datlen;

/* You might think we would want to increment dst->n_add_for_cb
* here too. But evbuffer_add above already took care of that.
*/
src->total_len -= nread;
src->n_del_for_cb += nread;

if (nread) {
evbuffer_invoke_callbacks_(dst);
evbuffer_invoke_callbacks_(src);
}
result = (int)nread;/*XXXX should change return type */

done:
EVBUFFER_UNLOCK2(src, dst);
return result;
}

unsigned char *
evbuffer_pullup(struct evbuffer *buf, ev_ssize_t size)
{
struct evbuffer_chain *chain, *next, *tmp, *last_with_data;
unsigned char *buffer, *result = NULL;
ev_ssize_t remaining;
int removed_last_with_data = 0;
int removed_last_with_datap = 0;

EVBUFFER_LOCK(buf);

chain = buf->first;

if (size < 0)
size = buf->total_len;
/* if size > buf->total_len, we cannot guarantee to the user that she
* is going to have a long enough buffer afterwards; so we return
* NULL */
if (size == 0 || (size_t)size > buf->total_len)
goto done;

/* No need to pull up anything; the first size bytes are
* already here. */
if (chain->off >= (size_t)size) {
result = chain->buffer + chain->misalign;
goto done;
}

/* Make sure that none of the chains we need to copy from is pinned. */
remaining = size - chain->off;
EVUTIL_ASSERT(remaining >= 0);
for (tmp=chain->next; tmp; tmp=tmp->next) {
if (CHAIN_PINNED(tmp))
goto done;
if (tmp->off >= (size_t)remaining)
break;
remaining -= tmp->off;
}

if (CHAIN_PINNED(chain)) {
size_t old_off = chain->off;
if (CHAIN_SPACE_LEN(chain) < size - chain->off) {
/* not enough room at end of chunk. */
goto done;
}
buffer = CHAIN_SPACE_PTR(chain);
tmp = chain;
tmp->off = size;
size -= old_off;
chain = chain->next;
} else if (chain->buffer_len - chain->misalign >= (size_t)size) {
/* already have enough space in the first chain */
size_t old_off = chain->off;
buffer = chain->buffer + chain->misalign + chain->off;
tmp = chain;
tmp->off = size;
size -= old_off;
chain = chain->next;
} else {
if ((tmp = evbuffer_chain_new(size)) == NULL) {
event_warn("%s: out of memory", __func__);
goto done;
}
buffer = tmp->buffer;
tmp->off = size;
buf->first = tmp;
}

/* TODO(niels): deal with buffers that point to NULL like sendfile */

/* Copy and free every chunk that will be entirely pulled into tmp */
last_with_data = *buf->last_with_datap;
for (; chain != NULL && (size_t)size >= chain->off; chain = next) {
next = chain->next;

if (chain->buffer) {
memcpy(buffer, chain->buffer + chain->misalign, chain->off);
size -= chain->off;
buffer += chain->off;
}
if (chain == last_with_data)
removed_last_with_data = 1;
if (&chain->next == buf->last_with_datap)
removed_last_with_datap = 1;

evbuffer_chain_free(chain);
}

if (chain != NULL) {
memcpy(buffer, chain->buffer + chain->misalign, size);
chain->misalign += size;
chain->off -= size;
} else {
buf->last = tmp;
}

tmp->next = chain;

if (removed_last_with_data) {
buf->last_with_datap = &buf->first;
} else if (removed_last_with_datap) {
if (buf->first->next && buf->first->next->off)
buf->last_with_datap = &buf->first->next;
else
buf->last_with_datap = &buf->first;
}

result = (tmp->buffer + tmp->misalign);

done:
EVBUFFER_UNLOCK(buf);
return result;
}

/*
* Reads a line terminated by either '\r\n', '\n\r' or '\r' or '\n'.
* The returned buffer needs to be freed by the called.
*/
char *
evbuffer_readline(struct evbuffer *buffer)
{
return evbuffer_readln(buffer, NULL, EVBUFFER_EOL_ANY);
}

static inline ev_ssize_t
evbuffer_strchr(struct evbuffer_ptr *it, const char chr)
{
struct evbuffer_chain *chain = it->internal_.chain;
size_t i = it->internal_.pos_in_chain;
while (chain != NULL) {
char *buffer = (char *)chain->buffer + chain->misalign;
char *cp = memchr(buffer+i, chr, chain->off-i);
if (cp) {
it->internal_.chain = chain;
it->internal_.pos_in_chain = cp - buffer;
it->pos += (cp - buffer - i);
return it->pos;
}
it->pos += chain->off - i;
i = 0;
chain = chain->next;
}

return (-1);
}

static inline char *
find_eol_char(char *s, size_t len)
{
#define CHUNK_SZ 128
/* Lots of benchmarking found this approach to be faster in practice
* than doing two memchrs over the whole buffer, doin a memchr on each
* char of the buffer, or trying to emulate memchr by hand. */
char *s_end, *cr, *lf;
s_end = s+len;
while (s < s_end) {
size_t chunk = (s + CHUNK_SZ < s_end) ? CHUNK_SZ : (s_end - s);
cr = memchr(s, '\r', chunk);
lf = memchr(s, '\n', chunk);
if (cr) {
if (lf && lf < cr)
return lf;
return cr;
} else if (lf) {
return lf;
}
s += CHUNK_SZ;
}

return NULL;
#undef CHUNK_SZ
}

static ev_ssize_t
evbuffer_find_eol_char(struct evbuffer_ptr *it)
{
struct evbuffer_chain *chain = it->internal_.chain;
size_t i = it->internal_.pos_in_chain;
while (chain != NULL) {
char *buffer = (char *)chain->buffer + chain->misalign;
char *cp = find_eol_char(buffer+i, chain->off-i);
if (cp) {
it->internal_.chain = chain;
it->internal_.pos_in_chain = cp - buffer;
it->pos += (cp - buffer) - i;
return it->pos;
}
it->pos += chain->off - i;
i = 0;
chain = chain->next;
}

return (-1);
}

static inline size_t
evbuffer_strspn(
struct evbuffer_ptr *ptr, const char *chrset)
{
size_t count = 0;
struct evbuffer_chain *chain = ptr->internal_.chain;
size_t i = ptr->internal_.pos_in_chain;

if (!chain)
return 0;

while (1) {
char *buffer = (char *)chain->buffer + chain->misalign;
for (; i < chain->off; ++i) {
const char *p = chrset;
while (*p) {
if (buffer[i] == *p++)
goto next;
}
ptr->internal_.chain = chain;
ptr->internal_.pos_in_chain = i;
ptr->pos += count;
return count;
next:
++count;
}
i = 0;

if (! chain->next) {
ptr->internal_.chain = chain;
ptr->internal_.pos_in_chain = i;
ptr->pos += count;
return count;
}

chain = chain->next;
}
}

static inline int
evbuffer_getchr(struct evbuffer_ptr *it)
{
struct evbuffer_chain *chain = it->internal_.chain;
size_t off = it->internal_.pos_in_chain;

if (chain == NULL)
return -1;

return (unsigned char)chain->buffer[chain->misalign + off];
}

struct evbuffer_ptr
evbuffer_search_eol(struct evbuffer *buffer,
struct evbuffer_ptr *start, size_t *eol_len_out,
enum evbuffer_eol_style eol_style)
{
struct evbuffer_ptr it, it2;
size_t extra_drain = 0;
int ok = 0;

/* Avoid locking in trivial edge cases */
if (start && start->internal_.chain == NULL) {
PTR_NOT_FOUND(&it);
if (eol_len_out)
*eol_len_out = extra_drain;
return it;
}

EVBUFFER_LOCK(buffer);

if (start) {
memcpy(&it, start, sizeof(it));
} else {
it.pos = 0;
it.internal_.chain = buffer->first;
it.internal_.pos_in_chain = 0;
}

/* the eol_style determines our first stop character and how many
* characters we are going to drain afterwards. */
switch (eol_style) {
case EVBUFFER_EOL_ANY:
if (evbuffer_find_eol_char(&it) < 0)
goto done;
memcpy(&it2, &it, sizeof(it));
extra_drain = evbuffer_strspn(&it2, "\r\n");
break;
case EVBUFFER_EOL_CRLF_STRICT: {
it = evbuffer_search(buffer, "\r\n", 2, &it);
if (it.pos < 0)
goto done;
extra_drain = 2;
break;
}
case EVBUFFER_EOL_CRLF: {
ev_ssize_t start_pos = it.pos;
/* Look for a LF ... */
if (evbuffer_strchr(&it, '\n') < 0)
goto done;
extra_drain = 1;
/* ... optionally preceeded by a CR. */
if (it.pos == start_pos)
break; /* If the first character is \n, don't back up */
/* This potentially does an extra linear walk over the first
* few chains. Probably, that's not too expensive unless you
* have a really pathological setup. */
memcpy(&it2, &it, sizeof(it));
if (evbuffer_ptr_subtract(buffer, &it2, 1)<0)
break;
if (evbuffer_getchr(&it2) == '\r') {
memcpy(&it, &it2, sizeof(it));
extra_drain = 2;
}
break;
}
case EVBUFFER_EOL_LF:
if (evbuffer_strchr(&it, '\n') < 0)
goto done;
extra_drain = 1;
break;
case EVBUFFER_EOL_NUL:
if (evbuffer_strchr(&it, '\0') < 0)
goto done;
extra_drain = 1;
break;
default:
goto done;
}

ok = 1;
done:
EVBUFFER_UNLOCK(buffer);

if (!ok)
PTR_NOT_FOUND(&it);
if (eol_len_out)
*eol_len_out = extra_drain;

return it;
}

char *
evbuffer_readln(struct evbuffer *buffer, size_t *n_read_out,
enum evbuffer_eol_style eol_style)
{
struct evbuffer_ptr it;
char *line;
size_t n_to_copy=0, extra_drain=0;
char *result = NULL;

EVBUFFER_LOCK(buffer);

if (buffer->freeze_start) {
goto done;
}

it = evbuffer_search_eol(buffer, NULL, &extra_drain, eol_style);
if (it.pos < 0)
goto done;
n_to_copy = it.pos;

if ((line = mm_malloc(n_to_copy+1)) == NULL) {
event_warn("%s: out of memory", __func__);
goto done;
}

evbuffer_remove(buffer, line, n_to_copy);
line[n_to_copy] = '\0';

evbuffer_drain(buffer, extra_drain);
result = line;
done:
EVBUFFER_UNLOCK(buffer);

if (n_read_out)
*n_read_out = result ? n_to_copy : 0;

return result;
}

#define EVBUFFER_CHAIN_MAX_AUTO_SIZE 4096

/* Adds data to an event buffer */

int
evbuffer_add(struct evbuffer *buf, const void *data_in, size_t datlen)
{
struct evbuffer_chain *chain, *tmp;
const unsigned char *data = data_in;
size_t remain, to_alloc;
int result = -1;

EVBUFFER_LOCK(buf);

if (buf->freeze_end) {
goto done;
}
/* Prevent buf->total_len overflow */
if (datlen > EV_SIZE_MAX - buf->total_len) {
goto done;
}

if (*buf->last_with_datap == NULL) {
chain = buf->last;
} else {
chain = *buf->last_with_datap;
}

/* If there are no chains allocated for this buffer, allocate one
* big enough to hold all the data. */
if (chain == NULL) {
chain = evbuffer_chain_new(datlen);
if (!chain)
goto done;
evbuffer_chain_insert(buf, chain);
}

if ((chain->flags & EVBUFFER_IMMUTABLE) == 0) {
/* Always true for mutable buffers */
EVUTIL_ASSERT(chain->misalign >= 0 &&
(ev_uint64_t)chain->misalign <= EVBUFFER_CHAIN_MAX);
remain = chain->buffer_len - (size_t)chain->misalign - chain->off;
if (remain >= datlen) {
/* there's enough space to hold all the data in the
* current last chain */
memcpy(chain->buffer + chain->misalign + chain->off,
data, datlen);
chain->off += datlen;
buf->total_len += datlen;
buf->n_add_for_cb += datlen;
goto out;
} else if (!CHAIN_PINNED(chain) &&
evbuffer_chain_should_realign(chain, datlen)) {
/* we can fit the data into the misalignment */
evbuffer_chain_align(chain);

memcpy(chain->buffer + chain->off, data, datlen);
chain->off += datlen;
buf->total_len += datlen;
buf->n_add_for_cb += datlen;
goto out;
}
} else {
/* we cannot write any data to the last chain */
remain = 0;
}

/* we need to add another chain */
to_alloc = chain->buffer_len;
if (to_alloc <= EVBUFFER_CHAIN_MAX_AUTO_SIZE/2)
to_alloc <<= 1;
if (datlen > to_alloc)
to_alloc = datlen;
tmp = evbuffer_chain_new(to_alloc);
if (tmp == NULL)
goto done;

if (remain) {
memcpy(chain->buffer + chain->misalign + chain->off,
data, remain);
chain->off += remain;
buf->total_len += remain;
buf->n_add_for_cb += remain;
}

data += remain;
datlen -= remain;

memcpy(tmp->buffer, data, datlen);
tmp->off = datlen;
evbuffer_chain_insert(buf, tmp);
buf->n_add_for_cb += datlen;

out:
evbuffer_invoke_callbacks_(buf);
result = 0;
done:
EVBUFFER_UNLOCK(buf);
return result;
}

int
evbuffer_prepend(struct evbuffer *buf, const void *data, size_t datlen)
{
struct evbuffer_chain *chain, *tmp;
int result = -1;

EVBUFFER_LOCK(buf);

if (datlen == 0) {
result = 0;
goto done;
}
if (buf->freeze_start) {
goto done;
}
if (datlen > EV_SIZE_MAX - buf->total_len) {
goto done;
}

chain = buf->first;

if (chain == NULL) {
chain = evbuffer_chain_new(datlen);
if (!chain)
goto done;
evbuffer_chain_insert(buf, chain);
}

/* we cannot touch immutable buffers */
if ((chain->flags & EVBUFFER_IMMUTABLE) == 0) {
/* Always true for mutable buffers */
EVUTIL_ASSERT(chain->misalign >= 0 &&
(ev_uint64_t)chain->misalign <= EVBUFFER_CHAIN_MAX);

/* If this chain is empty, we can treat it as
* 'empty at the beginning' rather than 'empty at the end' */
if (chain->off == 0)
chain->misalign = chain->buffer_len;

if ((size_t)chain->misalign >= datlen) {
/* we have enough space to fit everything */
memcpy(chain->buffer + chain->misalign - datlen,
data, datlen);
chain->off += datlen;
chain->misalign -= datlen;
buf->total_len += datlen;
buf->n_add_for_cb += datlen;
goto out;
} else if (chain->misalign) {
/* we can only fit some of the data. */
memcpy(chain->buffer,
(char*)data + datlen - chain->misalign,
(size_t)chain->misalign);
chain->off += (size_t)chain->misalign;
buf->total_len += (size_t)chain->misalign;
buf->n_add_for_cb += (size_t)chain->misalign;
datlen -= (size_t)chain->misalign;
chain->misalign = 0;
}
}

/* we need to add another chain */
if ((tmp = evbuffer_chain_new(datlen)) == NULL)
goto done;
buf->first = tmp;
if (buf->last_with_datap == &buf->first && chain->off)
buf->last_with_datap = &tmp->next;

tmp->next = chain;

tmp->off = datlen;
EVUTIL_ASSERT(datlen <= tmp->buffer_len);
tmp->misalign = tmp->buffer_len - datlen;

memcpy(tmp->buffer + tmp->misalign, data, datlen);
buf->total_len += datlen;
buf->n_add_for_cb += datlen;

out:
evbuffer_invoke_callbacks_(buf);
result = 0;
done:
EVBUFFER_UNLOCK(buf);
return result;
}

/** Helper: realigns the memory in chain->buffer so that misalign is 0. */
static void
evbuffer_chain_align(struct evbuffer_chain *chain)
{
EVUTIL_ASSERT(!(chain->flags & EVBUFFER_IMMUTABLE));
EVUTIL_ASSERT(!(chain->flags & EVBUFFER_MEM_PINNED_ANY));
memmove(chain->buffer, chain->buffer + chain->misalign, chain->off);
chain->misalign = 0;
}

#define MAX_TO_COPY_IN_EXPAND 4096
#define MAX_TO_REALIGN_IN_EXPAND 2048

/** Helper: return true iff we should realign chain to fit datalen bytes of
data in it. */
static int
evbuffer_chain_should_realign(struct evbuffer_chain *chain,
size_t datlen)
{
return chain->buffer_len - chain->off >= datlen &&
(chain->off < chain->buffer_len / 2) &&
(chain->off <= MAX_TO_REALIGN_IN_EXPAND);
}

/* Expands the available space in the event buffer to at least datlen, all in
* a single chunk. Return that chunk. */
static struct evbuffer_chain *
evbuffer_expand_singlechain(struct evbuffer *buf, size_t datlen)
{
struct evbuffer_chain *chain, **chainp;
struct evbuffer_chain *result = NULL;
ASSERT_EVBUFFER_LOCKED(buf);

chainp = buf->last_with_datap;

/* XXX If *chainp is no longer writeable, but has enough space in its
* misalign, this might be a bad idea: we could still use *chainp, not
* (*chainp)->next. */
if (*chainp && CHAIN_SPACE_LEN(*chainp) == 0)
chainp = &(*chainp)->next;

/* 'chain' now points to the first chain with writable space (if any)
* We will either use it, realign it, replace it, or resize it. */
chain = *chainp;

if (chain == NULL ||
(chain->flags & (EVBUFFER_IMMUTABLE|EVBUFFER_MEM_PINNED_ANY))) {
/* We can't use the last_with_data chain at all. Just add a
* new one that's big enough. */
goto insert_new;
}

/* If we can fit all the data, then we don't have to do anything */
if (CHAIN_SPACE_LEN(chain) >= datlen) {
result = chain;
goto ok;
}

/* If the chain is completely empty, just replace it by adding a new
* empty chain. */
if (chain->off == 0) {
goto insert_new;
}

/* If the misalignment plus the remaining space fulfills our data
* needs, we could just force an alignment to happen. Afterwards, we
* have enough space. But only do this if we're saving a lot of space
* and not moving too much data. Otherwise the space savings are
* probably offset by the time lost in copying.
*/
if (evbuffer_chain_should_realign(chain, datlen)) {
evbuffer_chain_align(chain);
result = chain;
goto ok;
}

/* At this point, we can either resize the last chunk with space in
* it, use the next chunk after it, or If we add a new chunk, we waste
* CHAIN_SPACE_LEN(chain) bytes in the former last chunk. If we
* resize, we have to copy chain->off bytes.
*/

/* Would expanding this chunk be affordable and worthwhile? */
if (CHAIN_SPACE_LEN(chain) < chain->buffer_len / 8 ||
chain->off > MAX_TO_COPY_IN_EXPAND ||
datlen >= (EVBUFFER_CHAIN_MAX - chain->off)) {
/* It's not worth resizing this chain. Can the next one be
* used? */
if (chain->next && CHAIN_SPACE_LEN(chain->next) >= datlen) {
/* Yes, we can just use the next chain (which should
* be empty. */
result = chain->next;
goto ok;
} else {
/* No; append a new chain (which will free all
* terminal empty chains.) */
goto insert_new;
}
} else {
/* Okay, we're going to try to resize this chain: Not doing so
* would waste at least 1/8 of its current allocation, and we
* can do so without having to copy more than
* MAX_TO_COPY_IN_EXPAND bytes. */
/* figure out how much space we need */
size_t length = chain->off + datlen;
struct evbuffer_chain *tmp = evbuffer_chain_new(length);
if (tmp == NULL)
goto err;

/* copy the data over that we had so far */
tmp->off = chain->off;
memcpy(tmp->buffer, chain->buffer + chain->misalign,
chain->off);
/* fix up the list */
EVUTIL_ASSERT(*chainp == chain);
result = *chainp = tmp;

if (buf->last == chain)
buf->last = tmp;

tmp->next = chain->next;
evbuffer_chain_free(chain);
goto ok;
}

insert_new:
result = evbuffer_chain_insert_new(buf, datlen);
if (!result)
goto err;
ok:
EVUTIL_ASSERT(result);
EVUTIL_ASSERT(CHAIN_SPACE_LEN(result) >= datlen);
err:
return result;
}

/* Make sure that datlen bytes are available for writing in the last n
* chains. Never copies or moves data. */
int
evbuffer_expand_fast_(struct evbuffer *buf, size_t datlen, int n)
{
struct evbuffer_chain *chain = buf->last, *tmp, *next;
size_t avail;
int used;

ASSERT_EVBUFFER_LOCKED(buf);
EVUTIL_ASSERT(n >= 2);

if (chain == NULL || (chain->flags & EVBUFFER_IMMUTABLE)) {
/* There is no last chunk, or we can't touch the last chunk.
* Just add a new chunk. */
chain = evbuffer_chain_new(datlen);
if (chain == NULL)
return (-1);

evbuffer_chain_insert(buf, chain);
return (0);
}

used = 0; /* number of chains we're using space in. */
avail = 0; /* how much space they have. */
/* How many bytes can we stick at the end of buffer as it is? Iterate
* over the chains at the end of the buffer, tring to see how much
* space we have in the first n. */
for (chain = *buf->last_with_datap; chain; chain = chain->next) {
if (chain->off) {
size_t space = (size_t) CHAIN_SPACE_LEN(chain);
EVUTIL_ASSERT(chain == *buf->last_with_datap);
if (space) {
avail += space;
++used;
}
} else {
/* No data in chain; realign it. */
chain->misalign = 0;
avail += chain->buffer_len;
++used;
}
if (avail >= datlen) {
/* There is already enough space. Just return */
return (0);
}
if (used == n)
break;
}

/* There wasn't enough space in the first n chains with space in
* them. Either add a new chain with enough space, or replace all
* empty chains with one that has enough space, depending on n. */
if (used < n) {
/* The loop ran off the end of the chains before it hit n
* chains; we can add another. */
EVUTIL_ASSERT(chain == NULL);

tmp = evbuffer_chain_new(datlen - avail);
if (tmp == NULL)
return (-1);

buf->last->next = tmp;
buf->last = tmp;
/* (we would only set last_with_data if we added the first
* chain. But if the buffer had no chains, we would have
* just allocated a new chain earlier) */
return (0);
} else {
/* Nuke _all_ the empty chains. */
int rmv_all = 0; /* True iff we removed last_with_data. */
chain = *buf->last_with_datap;
if (!chain->off) {
EVUTIL_ASSERT(chain == buf->first);
rmv_all = 1;
avail = 0;
} else {
/* can't overflow, since only mutable chains have
* huge misaligns. */
avail = (size_t) CHAIN_SPACE_LEN(chain);
chain = chain->next;
}

for (; chain; chain = next) {
next = chain->next;
EVUTIL_ASSERT(chain->off == 0);
evbuffer_chain_free(chain);
}
EVUTIL_ASSERT(datlen >= avail);
tmp = evbuffer_chain_new(datlen - avail);
if (tmp == NULL) {
if (rmv_all) {
ZERO_CHAIN(buf);
} else {
buf->last = *buf->last_with_datap;
(*buf->last_with_datap)->next = NULL;
}
return (-1);
}

if (rmv_all) {
buf->first = buf->last = tmp;
buf->last_with_datap = &buf->first;
} else {
(*buf->last_with_datap)->next = tmp;
buf->last = tmp;
}
return (0);
}
}

int
evbuffer_expand(struct evbuffer *buf, size_t datlen)
{
struct evbuffer_chain *chain;

EVBUFFER_LOCK(buf);
chain = evbuffer_expand_singlechain(buf, datlen);
EVBUFFER_UNLOCK(buf);
return chain ? 0 : -1;
}

/*
* Reads data from a file descriptor into a buffer.
*/

#if defined(EVENT__HAVE_SYS_UIO_H) || defined(_WIN32)
#define USE_IOVEC_IMPL
#endif

#ifdef USE_IOVEC_IMPL

#ifdef EVENT__HAVE_SYS_UIO_H
/* number of iovec we use for writev, fragmentation is going to determine
* how much we end up writing */

#define DEFAULT_WRITE_IOVEC 128

#if defined(UIO_MAXIOV) && UIO_MAXIOV < DEFAULT_WRITE_IOVEC
#define NUM_WRITE_IOVEC UIO_MAXIOV
#elif defined(IOV_MAX) && IOV_MAX < DEFAULT_WRITE_IOVEC
#define NUM_WRITE_IOVEC IOV_MAX
#else
#define NUM_WRITE_IOVEC DEFAULT_WRITE_IOVEC
#endif

#define IOV_TYPE struct iovec
#define IOV_PTR_FIELD iov_base
#define IOV_LEN_FIELD iov_len
#define IOV_LEN_TYPE size_t
#else
#define NUM_WRITE_IOVEC 16
#define IOV_TYPE WSABUF
#define IOV_PTR_FIELD buf
#define IOV_LEN_FIELD len
#define IOV_LEN_TYPE unsigned long
#endif
#endif
#define NUM_READ_IOVEC 4

#define EVBUFFER_MAX_READ 4096

/** Helper function to figure out which space to use for reading data into
an evbuffer. Internal use only.

@param buf The buffer to read into
@param howmuch How much we want to read.
@param vecs An array of two or more iovecs or WSABUFs.
@param n_vecs_avail The length of vecs
@param chainp A pointer to a variable to hold the first chain we're
reading into.
@param exact Boolean: if true, we do not provide more than 'howmuch'
space in the vectors, even if more space is available.
@return The number of buffers we're using.
*/
int
evbuffer_read_setup_vecs_(struct evbuffer *buf, ev_ssize_t howmuch,
struct evbuffer_iovec *vecs, int n_vecs_avail,
struct evbuffer_chain ***chainp, int exact)
{
struct evbuffer_chain *chain;
struct evbuffer_chain **firstchainp;
size_t so_far;
int i;
ASSERT_EVBUFFER_LOCKED(buf);

if (howmuch < 0)
return -1;

so_far = 0;
/* Let firstchain be the first chain with any space on it */
firstchainp = buf->last_with_datap;
EVUTIL_ASSERT(*firstchainp);
if (CHAIN_SPACE_LEN(*firstchainp) == 0) {
firstchainp = &(*firstchainp)->next;
}

chain = *firstchainp;
EVUTIL_ASSERT(chain);
for (i = 0; i < n_vecs_avail && so_far < (size_t)howmuch; ++i) {
size_t avail = (size_t) CHAIN_SPACE_LEN(chain);
if (avail > (howmuch - so_far) && exact)
avail = howmuch - so_far;
vecs[i].iov_base = (void *)CHAIN_SPACE_PTR(chain);
vecs[i].iov_len = avail;
so_far += avail;
chain = chain->next;
}

*chainp = firstchainp;
return i;
}

static int
get_n_bytes_readable_on_socket(evutil_socket_t fd)
{
#if defined(FIONREAD) && defined(_WIN32)
unsigned long lng = EVBUFFER_MAX_READ;
if (ioctlsocket(fd, FIONREAD, &lng) < 0)
return -1;
/* Can overflow, but mostly harmlessly. XXXX */
return (int)lng;
#elif defined(FIONREAD)
int n = EVBUFFER_MAX_READ;
if (ioctl(fd, FIONREAD, &n) < 0)
return -1;
return n;
#else
return EVBUFFER_MAX_READ;
#endif
}

/* TODO(niels): should this function return ev_ssize_t and take ev_ssize_t
* as howmuch? */
int
evbuffer_read(struct evbuffer *buf, evutil_socket_t fd, int howmuch)
{
struct evbuffer_chain **chainp;
int n;
int result;

#ifdef USE_IOVEC_IMPL
int nvecs, i, remaining;
#else
struct evbuffer_chain *chain;
unsigned char *p;
#endif

EVBUFFER_LOCK(buf);

if (buf->freeze_end) {
result = -1;
goto done;
}

n = get_n_bytes_readable_on_socket(fd);
if (n <= 0 || n > EVBUFFER_MAX_READ)
n = EVBUFFER_MAX_READ;
if (howmuch < 0 || howmuch > n)
howmuch = n;

#ifdef USE_IOVEC_IMPL
/* Since we can use iovecs, we're willing to use the last
* NUM_READ_IOVEC chains. */
if (evbuffer_expand_fast_(buf, howmuch, NUM_READ_IOVEC) == -1) {
result = -1;
goto done;
} else {
IOV_TYPE vecs[NUM_READ_IOVEC];
#ifdef EVBUFFER_IOVEC_IS_NATIVE_
nvecs = evbuffer_read_setup_vecs_(buf, howmuch, vecs,
NUM_READ_IOVEC, &chainp, 1);
#else
/* We aren't using the native struct iovec. Therefore,
we are on win32. */
struct evbuffer_iovec ev_vecs[NUM_READ_IOVEC];
nvecs = evbuffer_read_setup_vecs_(buf, howmuch, ev_vecs, 2,
&chainp, 1);

for (i=0; i < nvecs; ++i)
WSABUF_FROM_EVBUFFER_IOV(&vecs[i], &ev_vecs[i]);
#endif

#ifdef _WIN32
{
DWORD bytesRead;
DWORD flags=0;
if (WSARecv(fd, vecs, nvecs, &bytesRead, &flags, NULL, NULL)) {
/* The read failed. It might be a close,
* or it might be an error. */
if (WSAGetLastError() == WSAECONNABORTED)
n = 0;
else
n = -1;
} else
n = bytesRead;
}
#else
n = readv(fd, vecs, nvecs);
#endif
}

#else /*!USE_IOVEC_IMPL*/
/* If we don't have FIONREAD, we might waste some space here */
/* XXX we _will_ waste some space here if there is any space left
* over on buf->last. */
if ((chain = evbuffer_expand_singlechain(buf, howmuch)) == NULL) {
result = -1;
goto done;
}

/* We can append new data at this point */
p = chain->buffer + chain->misalign + chain->off;

#ifndef _WIN32
n = read(fd, p, howmuch);
#else
n = recv(fd, p, howmuch, 0);
#endif
#endif /* USE_IOVEC_IMPL */

if (n == -1) {
result = -1;
goto done;
}
if (n == 0) {
result = 0;
goto done;
}

#ifdef USE_IOVEC_IMPL
remaining = n;
for (i=0; i < nvecs; ++i) {
/* can't overflow, since only mutable chains have
* huge misaligns. */
size_t space = (size_t) CHAIN_SPACE_LEN(*chainp);
/* XXXX This is a kludge that can waste space in perverse
* situations. */
if (space > EVBUFFER_CHAIN_MAX)
space = EVBUFFER_CHAIN_MAX;
if ((ev_ssize_t)space < remaining) {
(*chainp)->off += space;
remaining -= (int)space;
} else {
(*chainp)->off += remaining;
buf->last_with_datap = chainp;
break;
}
chainp = &(*chainp)->next;
}
#else
chain->off += n;
advance_last_with_data(buf);
#endif
buf->total_len += n;
buf->n_add_for_cb += n;

/* Tell someone about changes in this buffer */
evbuffer_invoke_callbacks_(buf);
result = n;
done:
EVBUFFER_UNLOCK(buf);
return result;
}

#ifdef USE_IOVEC_IMPL
static inline int
evbuffer_write_iovec(struct evbuffer *buffer, evutil_socket_t fd,
ev_ssize_t howmuch)
{
IOV_TYPE iov[NUM_WRITE_IOVEC];
struct evbuffer_chain *chain = buffer->first;
int n, i = 0;

if (howmuch < 0)
return -1;

ASSERT_EVBUFFER_LOCKED(buffer);
/* XXX make this top out at some maximal data length? if the
* buffer has (say) 1MB in it, split over 128 chains, there's
* no way it all gets written in one go. */
while (chain != NULL && i < NUM_WRITE_IOVEC && howmuch) {
#ifdef USE_SENDFILE
/* we cannot write the file info via writev */
if (chain->flags & EVBUFFER_SENDFILE)
break;
#endif
iov[i].IOV_PTR_FIELD = (void *) (chain->buffer + chain->misalign);
if ((size_t)howmuch >= chain->off) {
/* XXXcould be problematic when windows supports mmap*/
iov[i++].IOV_LEN_FIELD = (IOV_LEN_TYPE)chain->off;
howmuch -= chain->off;
} else {
/* XXXcould be problematic when windows supports mmap*/
iov[i++].IOV_LEN_FIELD = (IOV_LEN_TYPE)howmuch;
break;
}
chain = chain->next;
}
if (! i)
return 0;

#ifdef _WIN32
{
DWORD bytesSent;
if (WSASend(fd, iov, i, &bytesSent, 0, NULL, NULL))
n = -1;
else
n = bytesSent;
}
#else
n = writev(fd, iov, i);
#endif
return (n);
}
#endif

#ifdef USE_SENDFILE
static inline int
evbuffer_write_sendfile(struct evbuffer *buffer, evutil_socket_t dest_fd,
ev_ssize_t howmuch)
{
struct evbuffer_chain *chain = buffer->first;
struct evbuffer_chain_file_segment *info =
EVBUFFER_CHAIN_EXTRA(struct evbuffer_chain_file_segment,
chain);
const int source_fd = info->segment->fd;
#if defined(SENDFILE_IS_MACOSX) || defined(SENDFILE_IS_FREEBSD)
int res;
ev_off_t len = chain->off;
#elif defined(SENDFILE_IS_LINUX) || defined(SENDFILE_IS_SOLARIS)
ev_ssize_t res;
off_t offset = chain->misalign;
#endif

ASSERT_EVBUFFER_LOCKED(buffer);

#if defined(SENDFILE_IS_MACOSX)
res = sendfile(source_fd, dest_fd, chain->misalign, &len, NULL, 0);
if (res == -1 && !EVUTIL_ERR_RW_RETRIABLE(errno))
return (-1);

return (len);
#elif defined(SENDFILE_IS_FREEBSD)
res = sendfile(source_fd, dest_fd, chain->misalign, chain->off, NULL, &len, 0);
if (res == -1 && !EVUTIL_ERR_RW_RETRIABLE(errno))
return (-1);

return (len);
#elif defined(SENDFILE_IS_LINUX)
/* TODO(niels): implement splice */
res = sendfile(dest_fd, source_fd, &offset, chain->off);
if (res == -1 && EVUTIL_ERR_RW_RETRIABLE(errno)) {
/* if this is EAGAIN or EINTR return 0; otherwise, -1 */
return (0);
}
return (res);
#elif defined(SENDFILE_IS_SOLARIS)
{
const off_t offset_orig = offset;
res = sendfile(dest_fd, source_fd, &offset, chain->off);
if (res == -1 && EVUTIL_ERR_RW_RETRIABLE(errno)) {
if (offset - offset_orig)
return offset - offset_orig;
/* if this is EAGAIN or EINTR and no bytes were
* written, return 0 */
return (0);
}
return (res);
}
#endif
}
#endif

int
evbuffer_write_atmost(struct evbuffer *buffer, evutil_socket_t fd,
ev_ssize_t howmuch)
{
int n = -1;

EVBUFFER_LOCK(buffer);

if (buffer->freeze_start) {
goto done;
}

if (howmuch < 0 || (size_t)howmuch > buffer->total_len)
howmuch = buffer->total_len;

if (howmuch > 0) {
#ifdef USE_SENDFILE
struct evbuffer_chain *chain = buffer->first;
if (chain != NULL && (chain->flags & EVBUFFER_SENDFILE))
n = evbuffer_write_sendfile(buffer, fd, howmuch);
else {
#endif
#ifdef USE_IOVEC_IMPL
n = evbuffer_write_iovec(buffer, fd, howmuch);
#elif defined(_WIN32)
/* XXX(nickm) Don't disable this code until we know if
* the WSARecv code above works. */
void *p = evbuffer_pullup(buffer, howmuch);
EVUTIL_ASSERT(p || !howmuch);
n = send(fd, p, howmuch, 0);
#else
void *p = evbuffer_pullup(buffer, howmuch);
EVUTIL_ASSERT(p || !howmuch);
n = write(fd, p, howmuch);
#endif
#ifdef USE_SENDFILE
}
#endif
}

if (n > 0)
evbuffer_drain(buffer, n);

done:
EVBUFFER_UNLOCK(buffer);
return (n);
}

int
evbuffer_write(struct evbuffer *buffer, evutil_socket_t fd)
{
return evbuffer_write_atmost(buffer, fd, -1);
}

unsigned char *
evbuffer_find(struct evbuffer *buffer, const unsigned char *what, size_t len)
{
unsigned char *search;
struct evbuffer_ptr ptr;

EVBUFFER_LOCK(buffer);

ptr = evbuffer_search(buffer, (const char *)what, len, NULL);
if (ptr.pos < 0) {
search = NULL;
} else {
search = evbuffer_pullup(buffer, ptr.pos + len);
if (search)
search += ptr.pos;
}
EVBUFFER_UNLOCK(buffer);
return search;
}

/* Subract howfar from the position of pos within
* buf. Returns 0 on success, -1 on failure.
*
* This isn't exposed yet, because of potential inefficiency issues.
* Maybe it should be. */
static int
evbuffer_ptr_subtract(struct evbuffer *buf, struct evbuffer_ptr *pos,
size_t howfar)
{
if (pos->pos < 0)
return -1;
if (howfar > (size_t)pos->pos)
return -1;
if (pos->internal_.chain && howfar <= pos->internal_.pos_in_chain) {
pos->internal_.pos_in_chain -= howfar;
pos->pos -= howfar;
return 0;
} else {
const size_t newpos = pos->pos - howfar;
/* Here's the inefficient part: it walks over the
* chains until we hit newpos. */
return evbuffer_ptr_set(buf, pos, newpos, EVBUFFER_PTR_SET);
}
}

int
evbuffer_ptr_set(struct evbuffer *buf, struct evbuffer_ptr *pos,
size_t position, enum evbuffer_ptr_how how)
{
size_t left = position;
struct evbuffer_chain *chain = NULL;
int result = 0;

EVBUFFER_LOCK(buf);

switch (how) {
case EVBUFFER_PTR_SET:
chain = buf->first;
pos->pos = position;
position = 0;
break;
case EVBUFFER_PTR_ADD:
/* this avoids iterating over all previous chains if
we just want to advance the position */
if (pos->pos < 0 || EV_SIZE_MAX - position < (size_t)pos->pos) {
EVBUFFER_UNLOCK(buf);
return -1;
}
chain = pos->internal_.chain;
pos->pos += position;
position = pos->internal_.pos_in_chain;
break;
}

EVUTIL_ASSERT(EV_SIZE_MAX - left >= position);
while (chain && position + left >= chain->off) {
left -= chain->off - position;
chain = chain->next;
position = 0;
}
if (chain) {
pos->internal_.chain = chain;
pos->internal_.pos_in_chain = position + left;
} else if (left == 0) {
/* The first byte in the (nonexistent) chain after the last chain */
pos->internal_.chain = NULL;
pos->internal_.pos_in_chain = 0;
} else {
PTR_NOT_FOUND(pos);
result = -1;
}

EVBUFFER_UNLOCK(buf);

return result;
}

/**
Compare the bytes in buf at position pos to the len bytes in mem. Return
less than 0, 0, or greater than 0 as memcmp.
*/
static int
evbuffer_ptr_memcmp(const struct evbuffer *buf, const struct evbuffer_ptr *pos,
const char *mem, size_t len)
{
struct evbuffer_chain *chain;
size_t position;
int r;

ASSERT_EVBUFFER_LOCKED(buf);

if (pos->pos < 0 ||
EV_SIZE_MAX - len < (size_t)pos->pos ||
pos->pos + len > buf->total_len)
return -1;

chain = pos->internal_.chain;
position = pos->internal_.pos_in_chain;
while (len && chain) {
size_t n_comparable;
if (len + position > chain->off)
n_comparable = chain->off - position;
else
n_comparable = len;
r = memcmp(chain->buffer + chain->misalign + position, mem,
n_comparable);
if (r)
return r;
mem += n_comparable;
len -= n_comparable;
position = 0;
chain = chain->next;
}

return 0;
}

struct evbuffer_ptr
evbuffer_search(struct evbuffer *buffer, const char *what, size_t len, const struct evbuffer_ptr *start)
{
return evbuffer_search_range(buffer, what, len, start, NULL);
}

struct evbuffer_ptr
evbuffer_search_range(struct evbuffer *buffer, const char *what, size_t len, const struct evbuffer_ptr *start, const struct evbuffer_ptr *end)
{
struct evbuffer_ptr pos;
struct evbuffer_chain *chain, *last_chain = NULL;
const unsigned char *p;
char first;

EVBUFFER_LOCK(buffer);

if (start) {
memcpy(&pos, start, sizeof(pos));
chain = pos.internal_.chain;
} else {
pos.pos = 0;
chain = pos.internal_.chain = buffer->first;
pos.internal_.pos_in_chain = 0;
}

if (end)
last_chain = end->internal_.chain;

if (!len || len > EV_SSIZE_MAX)
goto done;

first = what[0];

while (chain) {
const unsigned char *start_at =
chain->buffer + chain->misalign +
pos.internal_.pos_in_chain;
p = memchr(start_at, first,
chain->off - pos.internal_.pos_in_chain);
if (p) {
pos.pos += p - start_at;
pos.internal_.pos_in_chain += p - start_at;
if (!evbuffer_ptr_memcmp(buffer, &pos, what, len)) {
if (end && pos.pos + (ev_ssize_t)len > end->pos)
goto not_found;
else
goto done;
}
++pos.pos;
++pos.internal_.pos_in_chain;
if (pos.internal_.pos_in_chain == chain->off) {
chain = pos.internal_.chain = chain->next;
pos.internal_.pos_in_chain = 0;
}
} else {
if (chain == last_chain)
goto not_found;
pos.pos += chain->off - pos.internal_.pos_in_chain;
chain = pos.internal_.chain = chain->next;
pos.internal_.pos_in_chain = 0;
}
}

not_found:
PTR_NOT_FOUND(&pos);
done:
EVBUFFER_UNLOCK(buffer);
return pos;
}

int
evbuffer_peek(struct evbuffer *buffer, ev_ssize_t len,
struct evbuffer_ptr *start_at,
struct evbuffer_iovec *vec, int n_vec)
{
struct evbuffer_chain *chain;
int idx = 0;
ev_ssize_t len_so_far = 0;

/* Avoid locking in trivial edge cases */
if (start_at && start_at->internal_.chain == NULL)
return 0;

EVBUFFER_LOCK(buffer);

if (start_at) {
chain = start_at->internal_.chain;
len_so_far = chain->off
- start_at->internal_.pos_in_chain;
idx = 1;
if (n_vec > 0) {
vec[0].iov_base = (void *)(chain->buffer + chain->misalign
+ start_at->internal_.pos_in_chain);
vec[0].iov_len = len_so_far;
}
chain = chain->next;
} else {
chain = buffer->first;
}

if (n_vec == 0 && len < 0) {
/* If no vectors are provided and they asked for "everything",
* pretend they asked for the actual available amount. */
len = buffer->total_len;
if (start_at) {
len -= start_at->pos;
}
}

while (chain) {
if (len >= 0 && len_so_far >= len)
break;
if (idx<n_vec) {
vec[idx].iov_base = (void *)(chain->buffer + chain->misalign);
vec[idx].iov_len = chain->off;
} else if (len<0) {
break;
}
++idx;
len_so_far += chain->off;
chain = chain->next;
}

EVBUFFER_UNLOCK(buffer);

return idx;
}

int
evbuffer_add_vprintf(struct evbuffer *buf, const char *fmt, va_list ap)
{
char *buffer;
size_t space;
int sz, result = -1;
va_list aq;
struct evbuffer_chain *chain;

EVBUFFER_LOCK(buf);

if (buf->freeze_end) {
goto done;
}

/* make sure that at least some space is available */
if ((chain = evbuffer_expand_singlechain(buf, 64)) == NULL)
goto done;

for (;;) {
#if 0
size_t used = chain->misalign + chain->off;
buffer = (char *)chain->buffer + chain->misalign + chain->off;
EVUTIL_ASSERT(chain->buffer_len >= used);
space = chain->buffer_len - used;
#endif
buffer = (char*) CHAIN_SPACE_PTR(chain);
space = (size_t) CHAIN_SPACE_LEN(chain);

#ifndef va_copy
#define va_copy(dst, src) memcpy(&(dst), &(src), sizeof(va_list))
#endif
va_copy(aq, ap);

sz = evutil_vsnprintf(buffer, space, fmt, aq);

va_end(aq);

if (sz < 0)
goto done;
if (INT_MAX >= EVBUFFER_CHAIN_MAX &&
(size_t)sz >= EVBUFFER_CHAIN_MAX)
goto done;
if ((size_t)sz < space) {
chain->off += sz;
buf->total_len += sz;
buf->n_add_for_cb += sz;

advance_last_with_data(buf);
evbuffer_invoke_callbacks_(buf);
result = sz;
goto done;
}
if ((chain = evbuffer_expand_singlechain(buf, sz + 1)) == NULL)
goto done;
}
/* NOTREACHED */

done:
EVBUFFER_UNLOCK(buf);
return result;
}

int
evbuffer_add_printf(struct evbuffer *buf, const char *fmt, ...)
{
int res = -1;
va_list ap;

va_start(ap, fmt);
res = evbuffer_add_vprintf(buf, fmt, ap);
va_end(ap);

return (res);
}

int
evbuffer_add_reference(struct evbuffer *outbuf,
const void *data, size_t datlen,
evbuffer_ref_cleanup_cb cleanupfn, void *extra)
{
struct evbuffer_chain *chain;
struct evbuffer_chain_reference *info;
int result = -1;

chain = evbuffer_chain_new(sizeof(struct evbuffer_chain_reference));
if (!chain)
return (-1);
chain->flags |= EVBUFFER_REFERENCE | EVBUFFER_IMMUTABLE;
chain->buffer = (unsigned char *)data;
chain->buffer_len = datlen;
chain->off = datlen;

info = EVBUFFER_CHAIN_EXTRA(struct evbuffer_chain_reference, chain);
info->cleanupfn = cleanupfn;
info->extra = extra;

EVBUFFER_LOCK(outbuf);
if (outbuf->freeze_end) {
/* don't call chain_free; we do not want to actually invoke
* the cleanup function */
mm_free(chain);
goto done;
}
evbuffer_chain_insert(outbuf, chain);
outbuf->n_add_for_cb += datlen;

evbuffer_invoke_callbacks_(outbuf);

result = 0;
done:
EVBUFFER_UNLOCK(outbuf);

return result;
}

/* TODO(niels): we may want to add to automagically convert to mmap, in
* case evbuffer_remove() or evbuffer_pullup() are being used.
*/
struct evbuffer_file_segment *
evbuffer_file_segment_new(
int fd, ev_off_t offset, ev_off_t length, unsigned flags)
{
struct evbuffer_file_segment *seg =
mm_calloc(sizeof(struct evbuffer_file_segment), 1);
if (!seg)
return NULL;
seg->refcnt = 1;
seg->fd = fd;
seg->flags = flags;
seg->file_offset = offset;
seg->cleanup_cb = NULL;
seg->cleanup_cb_arg = NULL;
#ifdef _WIN32
#ifndef lseek
#define lseek _lseeki64
#endif
#ifndef fstat
#define fstat _fstat
#endif
#ifndef stat
#define stat _stat
#endif
#endif
if (length == -1) {
struct stat st;
if (fstat(fd, &st) < 0)
goto err;
length = st.st_size;
}
seg->length = length;

if (offset < 0 || length < 0 ||
((ev_uint64_t)length > EVBUFFER_CHAIN_MAX) ||
(ev_uint64_t)offset > (ev_uint64_t)(EVBUFFER_CHAIN_MAX - length))
goto err;

#if defined(USE_SENDFILE)
if (!(flags & EVBUF_FS_DISABLE_SENDFILE)) {
seg->can_sendfile = 1;
goto done;
}
#endif

if (evbuffer_file_segment_materialize(seg)<0)
goto err;

#if defined(USE_SENDFILE)
done:
#endif
if (!(flags & EVBUF_FS_DISABLE_LOCKING)) {
EVTHREAD_ALLOC_LOCK(seg->lock, 0);
}
return seg;
err:
mm_free(seg);
return NULL;
}

#ifdef EVENT__HAVE_MMAP
static long
get_page_size(void)
{
#ifdef SC_PAGE_SIZE
return sysconf(SC_PAGE_SIZE);
#elif defined(_SC_PAGE_SIZE)
return sysconf(_SC_PAGE_SIZE);
#else
return 1;
#endif
}
#endif

/* DOCDOC */
/* Requires lock */
static int
evbuffer_file_segment_materialize(struct evbuffer_file_segment *seg)
{
const unsigned flags = seg->flags;
const int fd = seg->fd;
const ev_off_t length = seg->length;
const ev_off_t offset = seg->file_offset;

if (seg->contents)
return 0; /* already materialized */

#if defined(EVENT__HAVE_MMAP)
if (!(flags & EVBUF_FS_DISABLE_MMAP)) {
off_t offset_rounded = 0, offset_leftover = 0;
void *mapped;
if (offset) {
/* mmap implementations don't generally like us
* to have an offset that isn't a round */
long page_size = get_page_size();
if (page_size == -1)
goto err;
offset_leftover = offset % page_size;
offset_rounded = offset - offset_leftover;
}
mapped = mmap(NULL, length + offset_leftover,
PROT_READ,
#ifdef MAP_NOCACHE
MAP_NOCACHE | /* ??? */
#endif
#ifdef MAP_FILE
MAP_FILE |
#endif
MAP_PRIVATE,
fd, offset_rounded);
if (mapped == MAP_FAILED) {
event_warn("%s: mmap(%d, %d, %zu) failed",
__func__, fd, 0, (size_t)(offset + length));
} else {
seg->mapping = mapped;
seg->contents = (char*)mapped+offset_leftover;
seg->mmap_offset = 0;
seg->is_mapping = 1;
goto done;
}
}
#endif
#ifdef _WIN32
if (!(flags & EVBUF_FS_DISABLE_MMAP)) {
intptr_t h = _get_osfhandle(fd);
HANDLE m;
ev_uint64_t total_size = length+offset;
if ((HANDLE)h == INVALID_HANDLE_VALUE)
goto err;
m = CreateFileMapping((HANDLE)h, NULL, PAGE_READONLY,
(total_size >> 32), total_size & 0xfffffffful,
NULL);
if (m != INVALID_HANDLE_VALUE) { /* Does h leak? */
seg->mapping_handle = m;
seg->mmap_offset = offset;
seg->is_mapping = 1;
goto done;
}
}
#endif
{
ev_off_t start_pos = lseek(fd, 0, SEEK_CUR), pos;
ev_off_t read_so_far = 0;
char *mem;
int e;
ev_ssize_t n = 0;
if (!(mem = mm_malloc(length)))
goto err;
if (start_pos < 0) {
mm_free(mem);
goto err;
}
if (lseek(fd, offset, SEEK_SET) < 0) {
mm_free(mem);
goto err;
}
while (read_so_far < length) {
n = read(fd, mem+read_so_far, length-read_so_far);
if (n <= 0)
break;
read_so_far += n;
}

e = errno;
pos = lseek(fd, start_pos, SEEK_SET);
if (n < 0 || (n == 0 && length > read_so_far)) {
mm_free(mem);
errno = e;
goto err;
} else if (pos < 0) {
mm_free(mem);
goto err;
}

seg->contents = mem;
}

done:
return 0;
err:
return -1;
}

void evbuffer_file_segment_add_cleanup_cb(struct evbuffer_file_segment *seg,
evbuffer_file_segment_cleanup_cb cb, void* arg)
{
EVUTIL_ASSERT(seg->refcnt > 0);
seg->cleanup_cb = cb;
seg->cleanup_cb_arg = arg;
}

void
evbuffer_file_segment_free(struct evbuffer_file_segment *seg)
{
int refcnt;
EVLOCK_LOCK(seg->lock, 0);
refcnt = --seg->refcnt;
EVLOCK_UNLOCK(seg->lock, 0);
if (refcnt > 0)
return;
EVUTIL_ASSERT(refcnt == 0);

if (seg->is_mapping) {
#ifdef _WIN32
CloseHandle(seg->mapping_handle);
#elif defined (EVENT__HAVE_MMAP)
off_t offset_leftover;
offset_leftover = seg->file_offset % get_page_size();
if (munmap(seg->mapping, seg->length + offset_leftover) == -1)
event_warn("%s: munmap failed", __func__);
#endif
} else if (seg->contents) {
mm_free(seg->contents);
}

if ((seg->flags & EVBUF_FS_CLOSE_ON_FREE) && seg->fd >= 0) {
close(seg->fd);
}

if (seg->cleanup_cb) {
(*seg->cleanup_cb)((struct evbuffer_file_segment const*)seg,
seg->flags, seg->cleanup_cb_arg);
seg->cleanup_cb = NULL;
seg->cleanup_cb_arg = NULL;
}

EVTHREAD_FREE_LOCK(seg->lock, 0);
mm_free(seg);
}

int
evbuffer_add_file_segment(struct evbuffer *buf,
struct evbuffer_file_segment *seg, ev_off_t offset, ev_off_t length)
{
struct evbuffer_chain *chain;
struct evbuffer_chain_file_segment *extra;
int can_use_sendfile = 0;

EVBUFFER_LOCK(buf);
EVLOCK_LOCK(seg->lock, 0);
if (buf->flags & EVBUFFER_FLAG_DRAINS_TO_FD) {
can_use_sendfile = 1;
} else {
if (!seg->contents) {
if (evbuffer_file_segment_materialize(seg)<0) {
EVLOCK_UNLOCK(seg->lock, 0);
EVBUFFER_UNLOCK(buf);
return -1;
}
}
}
EVLOCK_UNLOCK(seg->lock, 0);

if (buf->freeze_end)
goto err;

if (length < 0) {
if (offset > seg->length)
goto err;
length = seg->length - offset;
}

/* Can we actually add this? */
if (offset+length > seg->length)
goto err;

chain = evbuffer_chain_new(sizeof(struct evbuffer_chain_file_segment));
if (!chain)
goto err;
extra = EVBUFFER_CHAIN_EXTRA(struct evbuffer_chain_file_segment, chain);

chain->flags |= EVBUFFER_IMMUTABLE|EVBUFFER_FILESEGMENT;
if (can_use_sendfile && seg->can_sendfile) {
chain->flags |= EVBUFFER_SENDFILE;
chain->misalign = seg->file_offset + offset;
chain->off = length;
chain->buffer_len = chain->misalign + length;
} else if (seg->is_mapping) {
#ifdef _WIN32
ev_uint64_t total_offset = seg->mmap_offset+offset;
ev_uint64_t offset_rounded=0, offset_remaining=0;
LPVOID data;
if (total_offset) {
SYSTEM_INFO si;
memset(&si, 0, sizeof(si)); /* cargo cult */
GetSystemInfo(&si);
offset_remaining = total_offset % si.dwAllocationGranularity;
offset_rounded = total_offset - offset_remaining;
}
data = MapViewOfFile(
seg->mapping_handle,
FILE_MAP_READ,
offset_rounded >> 32,
offset_rounded & 0xfffffffful,
length + offset_remaining);
if (data == NULL) {
mm_free(chain);
goto err;
}
chain->buffer = (unsigned char*) data;
chain->buffer_len = length+offset_remaining;
chain->misalign = offset_remaining;
chain->off = length;
#else
chain->buffer = (unsigned char*)(seg->contents + offset);
chain->buffer_len = length;
chain->off = length;
#endif
} else {
chain->buffer = (unsigned char*)(seg->contents + offset);
chain->buffer_len = length;
chain->off = length;
}

EVLOCK_LOCK(seg->lock, 0);
++seg->refcnt;
EVLOCK_UNLOCK(seg->lock, 0);
extra->segment = seg;
buf->n_add_for_cb += length;
evbuffer_chain_insert(buf, chain);

evbuffer_invoke_callbacks_(buf);

EVBUFFER_UNLOCK(buf);

return 0;
err:
EVBUFFER_UNLOCK(buf);
evbuffer_file_segment_free(seg); /* Lowers the refcount */
return -1;
}

int
evbuffer_add_file(struct evbuffer *buf, int fd, ev_off_t offset, ev_off_t length)
{
struct evbuffer_file_segment *seg;
unsigned flags = EVBUF_FS_CLOSE_ON_FREE;
int r;

seg = evbuffer_file_segment_new(fd, offset, length, flags);
if (!seg)
return -1;
r = evbuffer_add_file_segment(buf, seg, 0, length);
if (r == 0)
evbuffer_file_segment_free(seg);
return r;
}

int
evbuffer_setcb(struct evbuffer *buffer, evbuffer_cb cb, void *cbarg)
{
EVBUFFER_LOCK(buffer);

if (!LIST_EMPTY(&buffer->callbacks))
evbuffer_remove_all_callbacks(buffer);

if (cb) {
struct evbuffer_cb_entry *ent =
evbuffer_add_cb(buffer, NULL, cbarg);
if (!ent) {
EVBUFFER_UNLOCK(buffer);
return -1;
}
ent->cb.cb_obsolete = cb;
ent->flags |= EVBUFFER_CB_OBSOLETE;
}
EVBUFFER_UNLOCK(buffer);
return 0;
}

struct evbuffer_cb_entry *
evbuffer_add_cb(struct evbuffer *buffer, evbuffer_cb_func cb, void *cbarg)
{
struct evbuffer_cb_entry *e;
if (! (e = mm_calloc(1, sizeof(struct evbuffer_cb_entry))))
return NULL;
EVBUFFER_LOCK(buffer);
e->cb.cb_func = cb;
e->cbarg = cbarg;
e->flags = EVBUFFER_CB_ENABLED;
LIST_INSERT_HEAD(&buffer->callbacks, e, next);
EVBUFFER_UNLOCK(buffer);
return e;
}

int
evbuffer_remove_cb_entry(struct evbuffer *buffer,
struct evbuffer_cb_entry *ent)
{
EVBUFFER_LOCK(buffer);
LIST_REMOVE(ent, next);
EVBUFFER_UNLOCK(buffer);
mm_free(ent);
return 0;
}

int
evbuffer_remove_cb(struct evbuffer *buffer, evbuffer_cb_func cb, void *cbarg)
{
struct evbuffer_cb_entry *cbent;
int result = -1;
EVBUFFER_LOCK(buffer);
LIST_FOREACH(cbent, &buffer->callbacks, next) {
if (cb == cbent->cb.cb_func && cbarg == cbent->cbarg) {
result = evbuffer_remove_cb_entry(buffer, cbent);
goto done;
}
}
done:
EVBUFFER_UNLOCK(buffer);
return result;
}

int
evbuffer_cb_set_flags(struct evbuffer *buffer,
struct evbuffer_cb_entry *cb, ev_uint32_t flags)
{
/* the user isn't allowed to mess with these. */
flags &= ~EVBUFFER_CB_INTERNAL_FLAGS;
EVBUFFER_LOCK(buffer);
cb->flags |= flags;
EVBUFFER_UNLOCK(buffer);
return 0;
}

int
evbuffer_cb_clear_flags(struct evbuffer *buffer,
struct evbuffer_cb_entry *cb, ev_uint32_t flags)
{
/* the user isn't allowed to mess with these. */
flags &= ~EVBUFFER_CB_INTERNAL_FLAGS;
EVBUFFER_LOCK(buffer);
cb->flags &= ~flags;
EVBUFFER_UNLOCK(buffer);
return 0;
}

int
evbuffer_freeze(struct evbuffer *buffer, int start)
{
EVBUFFER_LOCK(buffer);
if (start)
buffer->freeze_start = 1;
else
buffer->freeze_end = 1;
EVBUFFER_UNLOCK(buffer);
return 0;
}

int
evbuffer_unfreeze(struct evbuffer *buffer, int start)
{
EVBUFFER_LOCK(buffer);
if (start)
buffer->freeze_start = 0;
else
buffer->freeze_end = 0;
EVBUFFER_UNLOCK(buffer);
return 0;
}

#if 0
void
evbuffer_cb_suspend(struct evbuffer *buffer, struct evbuffer_cb_entry *cb)
{
if (!(cb->flags & EVBUFFER_CB_SUSPENDED)) {
cb->size_before_suspend = evbuffer_get_length(buffer);
cb->flags |= EVBUFFER_CB_SUSPENDED;
}
}

void
evbuffer_cb_unsuspend(struct evbuffer *buffer, struct evbuffer_cb_entry *cb)
{
if ((cb->flags & EVBUFFER_CB_SUSPENDED)) {
unsigned call = (cb->flags & EVBUFFER_CB_CALL_ON_UNSUSPEND);
size_t sz = cb->size_before_suspend;
cb->flags &= ~(EVBUFFER_CB_SUSPENDED|
EVBUFFER_CB_CALL_ON_UNSUSPEND);
cb->size_before_suspend = 0;
if (call && (cb->flags & EVBUFFER_CB_ENABLED)) {
cb->cb(buffer, sz, evbuffer_get_length(buffer), cb->cbarg);
}
}
}
#endif

int
evbuffer_get_callbacks_(struct evbuffer *buffer, struct event_callback **cbs,
int max_cbs)
{
int r = 0;
EVBUFFER_LOCK(buffer);
if (buffer->deferred_cbs) {
if (max_cbs < 1) {
r = -1;
goto done;
}
cbs[0] = &buffer->deferred;
r = 1;
}
done:
EVBUFFER_UNLOCK(buffer);
return r;
}