1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/ipc/chromium/src/third_party/libevent/evbuffer-internal.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,281 @@
1.4 +/*
1.5 + * Copyright (c) 2000-2007 Niels Provos <provos@citi.umich.edu>
1.6 + * Copyright (c) 2007-2012 Niels Provos and Nick Mathewson
1.7 + *
1.8 + * Redistribution and use in source and binary forms, with or without
1.9 + * modification, are permitted provided that the following conditions
1.10 + * are met:
1.11 + * 1. Redistributions of source code must retain the above copyright
1.12 + * notice, this list of conditions and the following disclaimer.
1.13 + * 2. Redistributions in binary form must reproduce the above copyright
1.14 + * notice, this list of conditions and the following disclaimer in the
1.15 + * documentation and/or other materials provided with the distribution.
1.16 + * 3. The name of the author may not be used to endorse or promote products
1.17 + * derived from this software without specific prior written permission.
1.18 + *
1.19 + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
1.20 + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
1.21 + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
1.22 + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
1.23 + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
1.24 + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
1.25 + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
1.26 + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
1.27 + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
1.28 + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.29 + */
1.30 +#ifndef _EVBUFFER_INTERNAL_H_
1.31 +#define _EVBUFFER_INTERNAL_H_
1.32 +
1.33 +#ifdef __cplusplus
1.34 +extern "C" {
1.35 +#endif
1.36 +
1.37 +#include "event2/event-config.h"
1.38 +#include "event2/util.h"
1.39 +#include "util-internal.h"
1.40 +#include "defer-internal.h"
1.41 +
1.42 +/* Experimental cb flag: "never deferred." Implementation note:
1.43 + * these callbacks may get an inaccurate view of n_del/n_added in their
1.44 + * arguments. */
1.45 +#define EVBUFFER_CB_NODEFER 2
1.46 +
1.47 +#ifdef WIN32
1.48 +#include <winsock2.h>
1.49 +#endif
1.50 +#include <sys/queue.h>
1.51 +
1.52 +/* Minimum allocation for a chain. We define this so that we're burning no
1.53 + * more than 5% of each allocation on overhead. It would be nice to lose even
1.54 + * less space, though. */
1.55 +#if _EVENT_SIZEOF_VOID_P < 8
1.56 +#define MIN_BUFFER_SIZE 512
1.57 +#else
1.58 +#define MIN_BUFFER_SIZE 1024
1.59 +#endif
1.60 +
1.61 +/** A single evbuffer callback for an evbuffer. This function will be invoked
1.62 + * when bytes are added to or removed from the evbuffer. */
1.63 +struct evbuffer_cb_entry {
1.64 + /** Structures to implement a doubly-linked queue of callbacks */
1.65 + TAILQ_ENTRY(evbuffer_cb_entry) next;
1.66 + /** The callback function to invoke when this callback is called.
1.67 + If EVBUFFER_CB_OBSOLETE is set in flags, the cb_obsolete field is
1.68 + valid; otherwise, cb_func is valid. */
1.69 + union {
1.70 + evbuffer_cb_func cb_func;
1.71 + evbuffer_cb cb_obsolete;
1.72 + } cb;
1.73 + /** Argument to pass to cb. */
1.74 + void *cbarg;
1.75 + /** Currently set flags on this callback. */
1.76 + ev_uint32_t flags;
1.77 +};
1.78 +
1.79 +struct bufferevent;
1.80 +struct evbuffer_chain;
1.81 +struct evbuffer {
1.82 + /** The first chain in this buffer's linked list of chains. */
1.83 + struct evbuffer_chain *first;
1.84 + /** The last chain in this buffer's linked list of chains. */
1.85 + struct evbuffer_chain *last;
1.86 +
1.87 + /** Pointer to the next pointer pointing at the 'last_with_data' chain.
1.88 + *
1.89 + * To unpack:
1.90 + *
1.91 + * The last_with_data chain is the last chain that has any data in it.
1.92 + * If all chains in the buffer are empty, it is the first chain.
1.93 + * If the buffer has no chains, it is NULL.
1.94 + *
1.95 + * The last_with_datap pointer points at _whatever 'next' pointer_
1.96 + * points at the last_with_datap chain. If the last_with_data chain
1.97 + * is the first chain, or it is NULL, then the last_with_datap pointer
1.98 + * is &buf->first.
1.99 + */
1.100 + struct evbuffer_chain **last_with_datap;
1.101 +
1.102 + /** Total amount of bytes stored in all chains.*/
1.103 + size_t total_len;
1.104 +
1.105 + /** Number of bytes we have added to the buffer since we last tried to
1.106 + * invoke callbacks. */
1.107 + size_t n_add_for_cb;
1.108 + /** Number of bytes we have removed from the buffer since we last
1.109 + * tried to invoke callbacks. */
1.110 + size_t n_del_for_cb;
1.111 +
1.112 +#ifndef _EVENT_DISABLE_THREAD_SUPPORT
1.113 + /** A lock used to mediate access to this buffer. */
1.114 + void *lock;
1.115 +#endif
1.116 + /** True iff we should free the lock field when we free this
1.117 + * evbuffer. */
1.118 + unsigned own_lock : 1;
1.119 + /** True iff we should not allow changes to the front of the buffer
1.120 + * (drains or prepends). */
1.121 + unsigned freeze_start : 1;
1.122 + /** True iff we should not allow changes to the end of the buffer
1.123 + * (appends) */
1.124 + unsigned freeze_end : 1;
1.125 + /** True iff this evbuffer's callbacks are not invoked immediately
1.126 + * upon a change in the buffer, but instead are deferred to be invoked
1.127 + * from the event_base's loop. Useful for preventing enormous stack
1.128 + * overflows when we have mutually recursive callbacks, and for
1.129 + * serializing callbacks in a single thread. */
1.130 + unsigned deferred_cbs : 1;
1.131 +#ifdef WIN32
1.132 + /** True iff this buffer is set up for overlapped IO. */
1.133 + unsigned is_overlapped : 1;
1.134 +#endif
1.135 + /** Zero or more EVBUFFER_FLAG_* bits */
1.136 + ev_uint32_t flags;
1.137 +
1.138 + /** Used to implement deferred callbacks. */
1.139 + struct deferred_cb_queue *cb_queue;
1.140 +
1.141 + /** A reference count on this evbuffer. When the reference count
1.142 + * reaches 0, the buffer is destroyed. Manipulated with
1.143 + * evbuffer_incref and evbuffer_decref_and_unlock and
1.144 + * evbuffer_free. */
1.145 + int refcnt;
1.146 +
1.147 + /** A deferred_cb handle to make all of this buffer's callbacks
1.148 + * invoked from the event loop. */
1.149 + struct deferred_cb deferred;
1.150 +
1.151 + /** A doubly-linked-list of callback functions */
1.152 + TAILQ_HEAD(evbuffer_cb_queue, evbuffer_cb_entry) callbacks;
1.153 +
1.154 + /** The parent bufferevent object this evbuffer belongs to.
1.155 + * NULL if the evbuffer stands alone. */
1.156 + struct bufferevent *parent;
1.157 +};
1.158 +
1.159 +/** A single item in an evbuffer. */
1.160 +struct evbuffer_chain {
1.161 + /** points to next buffer in the chain */
1.162 + struct evbuffer_chain *next;
1.163 +
1.164 + /** total allocation available in the buffer field. */
1.165 + size_t buffer_len;
1.166 +
1.167 + /** unused space at the beginning of buffer or an offset into a
1.168 + * file for sendfile buffers. */
1.169 + ev_off_t misalign;
1.170 +
1.171 + /** Offset into buffer + misalign at which to start writing.
1.172 + * In other words, the total number of bytes actually stored
1.173 + * in buffer. */
1.174 + size_t off;
1.175 +
1.176 + /** Set if special handling is required for this chain */
1.177 + unsigned flags;
1.178 +#define EVBUFFER_MMAP 0x0001 /**< memory in buffer is mmaped */
1.179 +#define EVBUFFER_SENDFILE 0x0002 /**< a chain used for sendfile */
1.180 +#define EVBUFFER_REFERENCE 0x0004 /**< a chain with a mem reference */
1.181 +#define EVBUFFER_IMMUTABLE 0x0008 /**< read-only chain */
1.182 + /** a chain that mustn't be reallocated or freed, or have its contents
1.183 + * memmoved, until the chain is un-pinned. */
1.184 +#define EVBUFFER_MEM_PINNED_R 0x0010
1.185 +#define EVBUFFER_MEM_PINNED_W 0x0020
1.186 +#define EVBUFFER_MEM_PINNED_ANY (EVBUFFER_MEM_PINNED_R|EVBUFFER_MEM_PINNED_W)
1.187 + /** a chain that should be freed, but can't be freed until it is
1.188 + * un-pinned. */
1.189 +#define EVBUFFER_DANGLING 0x0040
1.190 +
1.191 + /** Usually points to the read-write memory belonging to this
1.192 + * buffer allocated as part of the evbuffer_chain allocation.
1.193 + * For mmap, this can be a read-only buffer and
1.194 + * EVBUFFER_IMMUTABLE will be set in flags. For sendfile, it
1.195 + * may point to NULL.
1.196 + */
1.197 + unsigned char *buffer;
1.198 +};
1.199 +
1.200 +/* this is currently used by both mmap and sendfile */
1.201 +/* TODO(niels): something strange needs to happen for Windows here, I am not
1.202 + * sure what that is, but it needs to get looked into.
1.203 + */
1.204 +struct evbuffer_chain_fd {
1.205 + int fd; /**< the fd associated with this chain */
1.206 +};
1.207 +
1.208 +/** callback for a reference buffer; lets us know what to do with it when
1.209 + * we're done with it. */
1.210 +struct evbuffer_chain_reference {
1.211 + evbuffer_ref_cleanup_cb cleanupfn;
1.212 + void *extra;
1.213 +};
1.214 +
1.215 +#define EVBUFFER_CHAIN_SIZE sizeof(struct evbuffer_chain)
1.216 +/** Return a pointer to extra data allocated along with an evbuffer. */
1.217 +#define EVBUFFER_CHAIN_EXTRA(t, c) (t *)((struct evbuffer_chain *)(c) + 1)
1.218 +
1.219 +/** Assert that we are holding the lock on an evbuffer */
1.220 +#define ASSERT_EVBUFFER_LOCKED(buffer) \
1.221 + EVLOCK_ASSERT_LOCKED((buffer)->lock)
1.222 +
1.223 +#define EVBUFFER_LOCK(buffer) \
1.224 + do { \
1.225 + EVLOCK_LOCK((buffer)->lock, 0); \
1.226 + } while (0)
1.227 +#define EVBUFFER_UNLOCK(buffer) \
1.228 + do { \
1.229 + EVLOCK_UNLOCK((buffer)->lock, 0); \
1.230 + } while (0)
1.231 +#define EVBUFFER_LOCK2(buffer1, buffer2) \
1.232 + do { \
1.233 + EVLOCK_LOCK2((buffer1)->lock, (buffer2)->lock, 0, 0); \
1.234 + } while (0)
1.235 +#define EVBUFFER_UNLOCK2(buffer1, buffer2) \
1.236 + do { \
1.237 + EVLOCK_UNLOCK2((buffer1)->lock, (buffer2)->lock, 0, 0); \
1.238 + } while (0)
1.239 +
1.240 +/** Increase the reference count of buf by one. */
1.241 +void _evbuffer_incref(struct evbuffer *buf);
1.242 +/** Increase the reference count of buf by one and acquire the lock. */
1.243 +void _evbuffer_incref_and_lock(struct evbuffer *buf);
1.244 +/** Pin a single buffer chain using a given flag. A pinned chunk may not be
1.245 + * moved or freed until it is unpinned. */
1.246 +void _evbuffer_chain_pin(struct evbuffer_chain *chain, unsigned flag);
1.247 +/** Unpin a single buffer chain using a given flag. */
1.248 +void _evbuffer_chain_unpin(struct evbuffer_chain *chain, unsigned flag);
1.249 +/** As evbuffer_free, but requires that we hold a lock on the buffer, and
1.250 + * releases the lock before freeing it and the buffer. */
1.251 +void _evbuffer_decref_and_unlock(struct evbuffer *buffer);
1.252 +
1.253 +/** As evbuffer_expand, but does not guarantee that the newly allocated memory
1.254 + * is contiguous. Instead, it may be split across two or more chunks. */
1.255 +int _evbuffer_expand_fast(struct evbuffer *, size_t, int);
1.256 +
1.257 +/** Helper: prepares for a readv/WSARecv call by expanding the buffer to
1.258 + * hold enough memory to read 'howmuch' bytes in possibly noncontiguous memory.
1.259 + * Sets up the one or two iovecs in 'vecs' to point to the free memory and its
1.260 + * extent, and *chainp to point to the first chain that we'll try to read into.
1.261 + * Returns the number of vecs used.
1.262 + */
1.263 +int _evbuffer_read_setup_vecs(struct evbuffer *buf, ev_ssize_t howmuch,
1.264 + struct evbuffer_iovec *vecs, int n_vecs, struct evbuffer_chain ***chainp,
1.265 + int exact);
1.266 +
1.267 +/* Helper macro: copies an evbuffer_iovec in ei to a win32 WSABUF in i. */
1.268 +#define WSABUF_FROM_EVBUFFER_IOV(i,ei) do { \
1.269 + (i)->buf = (ei)->iov_base; \
1.270 + (i)->len = (unsigned long)(ei)->iov_len; \
1.271 + } while (0)
1.272 +/* XXXX the cast above is safe for now, but not if we allow mmaps on win64.
1.273 + * See note in buffer_iocp's launch_write function */
1.274 +
1.275 +/** Set the parent bufferevent object for buf to bev */
1.276 +void evbuffer_set_parent(struct evbuffer *buf, struct bufferevent *bev);
1.277 +
1.278 +void evbuffer_invoke_callbacks(struct evbuffer *buf);
1.279 +
1.280 +#ifdef __cplusplus
1.281 +}
1.282 +#endif
1.283 +
1.284 +#endif /* _EVBUFFER_INTERNAL_H_ */
