Squashed 'third_party/libevent/' content from commit d8ceae8
Change-Id: I84e1b23561eb225b9f288717b028e6bc9e5a27e1
git-subtree-dir: third_party/libevent
git-subtree-split: d8ceae81b83f3d0a56e2f41d4c429b2702a8e302
diff --git a/evbuffer-internal.h b/evbuffer-internal.h
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+/*
+ * Copyright (c) 2000-2007 Niels Provos <provos@citi.umich.edu>
+ * 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.
+ */
+#ifndef _EVBUFFER_INTERNAL_H_
+#define _EVBUFFER_INTERNAL_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "event2/event-config.h"
+#include "event2/util.h"
+#include "util-internal.h"
+#include "defer-internal.h"
+
+/* Experimental cb flag: "never deferred." Implementation note:
+ * these callbacks may get an inaccurate view of n_del/n_added in their
+ * arguments. */
+#define EVBUFFER_CB_NODEFER 2
+
+#ifdef WIN32
+#include <winsock2.h>
+#endif
+#include <sys/queue.h>
+
+/* Minimum allocation for a chain. We define this so that we're burning no
+ * more than 5% of each allocation on overhead. It would be nice to lose even
+ * less space, though. */
+#if _EVENT_SIZEOF_VOID_P < 8
+#define MIN_BUFFER_SIZE 512
+#else
+#define MIN_BUFFER_SIZE 1024
+#endif
+
+/** A single evbuffer callback for an evbuffer. This function will be invoked
+ * when bytes are added to or removed from the evbuffer. */
+struct evbuffer_cb_entry {
+ /** Structures to implement a doubly-linked queue of callbacks */
+ TAILQ_ENTRY(evbuffer_cb_entry) next;
+ /** The callback function to invoke when this callback is called.
+ If EVBUFFER_CB_OBSOLETE is set in flags, the cb_obsolete field is
+ valid; otherwise, cb_func is valid. */
+ union {
+ evbuffer_cb_func cb_func;
+ evbuffer_cb cb_obsolete;
+ } cb;
+ /** Argument to pass to cb. */
+ void *cbarg;
+ /** Currently set flags on this callback. */
+ ev_uint32_t flags;
+};
+
+struct bufferevent;
+struct evbuffer_chain;
+struct evbuffer {
+ /** The first chain in this buffer's linked list of chains. */
+ struct evbuffer_chain *first;
+ /** The last chain in this buffer's linked list of chains. */
+ struct evbuffer_chain *last;
+
+ /** Pointer to the next pointer pointing at the 'last_with_data' chain.
+ *
+ * To unpack:
+ *
+ * The last_with_data chain is the last chain that has any data in it.
+ * If all chains in the buffer are empty, it is the first chain.
+ * If the buffer has no chains, it is NULL.
+ *
+ * The last_with_datap pointer points at _whatever 'next' pointer_
+ * points at the last_with_datap chain. If the last_with_data chain
+ * is the first chain, or it is NULL, then the last_with_datap pointer
+ * is &buf->first.
+ */
+ struct evbuffer_chain **last_with_datap;
+
+ /** Total amount of bytes stored in all chains.*/
+ size_t total_len;
+
+ /** Number of bytes we have added to the buffer since we last tried to
+ * invoke callbacks. */
+ size_t n_add_for_cb;
+ /** Number of bytes we have removed from the buffer since we last
+ * tried to invoke callbacks. */
+ size_t n_del_for_cb;
+
+#ifndef _EVENT_DISABLE_THREAD_SUPPORT
+ /** A lock used to mediate access to this buffer. */
+ void *lock;
+#endif
+ /** True iff we should free the lock field when we free this
+ * evbuffer. */
+ unsigned own_lock : 1;
+ /** True iff we should not allow changes to the front of the buffer
+ * (drains or prepends). */
+ unsigned freeze_start : 1;
+ /** True iff we should not allow changes to the end of the buffer
+ * (appends) */
+ unsigned freeze_end : 1;
+ /** True iff this evbuffer's callbacks are not invoked immediately
+ * upon a change in the buffer, but instead are deferred to be invoked
+ * from the event_base's loop. Useful for preventing enormous stack
+ * overflows when we have mutually recursive callbacks, and for
+ * serializing callbacks in a single thread. */
+ unsigned deferred_cbs : 1;
+#ifdef WIN32
+ /** True iff this buffer is set up for overlapped IO. */
+ unsigned is_overlapped : 1;
+#endif
+ /** Zero or more EVBUFFER_FLAG_* bits */
+ ev_uint32_t flags;
+
+ /** Used to implement deferred callbacks. */
+ struct deferred_cb_queue *cb_queue;
+
+ /** A reference count on this evbuffer. When the reference count
+ * reaches 0, the buffer is destroyed. Manipulated with
+ * evbuffer_incref and evbuffer_decref_and_unlock and
+ * evbuffer_free. */
+ int refcnt;
+
+ /** A deferred_cb handle to make all of this buffer's callbacks
+ * invoked from the event loop. */
+ struct deferred_cb deferred;
+
+ /** A doubly-linked-list of callback functions */
+ TAILQ_HEAD(evbuffer_cb_queue, evbuffer_cb_entry) callbacks;
+
+ /** The parent bufferevent object this evbuffer belongs to.
+ * NULL if the evbuffer stands alone. */
+ struct bufferevent *parent;
+};
+
+#if _EVENT_SIZEOF_OFF_T < _EVENT_SIZEOF_SIZE_T
+typedef ev_ssize_t ev_misalign_t;
+#define EVBUFFER_CHAIN_MAX ((size_t)EV_SSIZE_MAX)
+#else
+typedef ev_off_t ev_misalign_t;
+#if _EVENT_SIZEOF_OFF_T > _EVENT_SIZEOF_SIZE_T
+#define EVBUFFER_CHAIN_MAX EV_SIZE_MAX
+#else
+#define EVBUFFER_CHAIN_MAX ((size_t)EV_SSIZE_MAX)
+#endif
+#endif
+
+/** A single item in an evbuffer. */
+struct evbuffer_chain {
+ /** points to next buffer in the chain */
+ struct evbuffer_chain *next;
+
+ /** total allocation available in the buffer field. */
+ size_t buffer_len;
+
+ /** unused space at the beginning of buffer or an offset into a
+ * file for sendfile buffers. */
+ ev_misalign_t misalign;
+
+ /** Offset into buffer + misalign at which to start writing.
+ * In other words, the total number of bytes actually stored
+ * in buffer. */
+ size_t off;
+
+ /** Set if special handling is required for this chain */
+ unsigned flags;
+#define EVBUFFER_MMAP 0x0001 /**< memory in buffer is mmaped */
+#define EVBUFFER_SENDFILE 0x0002 /**< a chain used for sendfile */
+#define EVBUFFER_REFERENCE 0x0004 /**< a chain with a mem reference */
+#define EVBUFFER_IMMUTABLE 0x0008 /**< read-only chain */
+ /** a chain that mustn't be reallocated or freed, or have its contents
+ * memmoved, until the chain is un-pinned. */
+#define EVBUFFER_MEM_PINNED_R 0x0010
+#define EVBUFFER_MEM_PINNED_W 0x0020
+#define EVBUFFER_MEM_PINNED_ANY (EVBUFFER_MEM_PINNED_R|EVBUFFER_MEM_PINNED_W)
+ /** a chain that should be freed, but can't be freed until it is
+ * un-pinned. */
+#define EVBUFFER_DANGLING 0x0040
+
+ /** Usually points to the read-write memory belonging to this
+ * buffer allocated as part of the evbuffer_chain allocation.
+ * For mmap, this can be a read-only buffer and
+ * EVBUFFER_IMMUTABLE will be set in flags. For sendfile, it
+ * may point to NULL.
+ */
+ unsigned char *buffer;
+};
+
+/* this is currently used by both mmap and sendfile */
+/* TODO(niels): something strange needs to happen for Windows here, I am not
+ * sure what that is, but it needs to get looked into.
+ */
+struct evbuffer_chain_fd {
+ int fd; /**< the fd associated with this chain */
+};
+
+/** callback for a reference buffer; lets us know what to do with it when
+ * we're done with it. */
+struct evbuffer_chain_reference {
+ evbuffer_ref_cleanup_cb cleanupfn;
+ void *extra;
+};
+
+#define EVBUFFER_CHAIN_SIZE sizeof(struct evbuffer_chain)
+/** Return a pointer to extra data allocated along with an evbuffer. */
+#define EVBUFFER_CHAIN_EXTRA(t, c) (t *)((struct evbuffer_chain *)(c) + 1)
+
+/** Assert that we are holding the lock on an evbuffer */
+#define ASSERT_EVBUFFER_LOCKED(buffer) \
+ EVLOCK_ASSERT_LOCKED((buffer)->lock)
+
+#define EVBUFFER_LOCK(buffer) \
+ do { \
+ EVLOCK_LOCK((buffer)->lock, 0); \
+ } while (0)
+#define EVBUFFER_UNLOCK(buffer) \
+ do { \
+ EVLOCK_UNLOCK((buffer)->lock, 0); \
+ } while (0)
+#define EVBUFFER_LOCK2(buffer1, buffer2) \
+ do { \
+ EVLOCK_LOCK2((buffer1)->lock, (buffer2)->lock, 0, 0); \
+ } while (0)
+#define EVBUFFER_UNLOCK2(buffer1, buffer2) \
+ do { \
+ EVLOCK_UNLOCK2((buffer1)->lock, (buffer2)->lock, 0, 0); \
+ } while (0)
+
+/** Increase the reference count of buf by one. */
+void _evbuffer_incref(struct evbuffer *buf);
+/** Increase the reference count of buf by one and acquire the lock. */
+void _evbuffer_incref_and_lock(struct evbuffer *buf);
+/** Pin a single buffer chain using a given flag. A pinned chunk may not be
+ * moved or freed until it is unpinned. */
+void _evbuffer_chain_pin(struct evbuffer_chain *chain, unsigned flag);
+/** Unpin a single buffer chain using a given flag. */
+void _evbuffer_chain_unpin(struct evbuffer_chain *chain, unsigned flag);
+/** As evbuffer_free, but requires that we hold a lock on the buffer, and
+ * releases the lock before freeing it and the buffer. */
+void _evbuffer_decref_and_unlock(struct evbuffer *buffer);
+
+/** As evbuffer_expand, but does not guarantee that the newly allocated memory
+ * is contiguous. Instead, it may be split across two or more chunks. */
+int _evbuffer_expand_fast(struct evbuffer *, size_t, int);
+
+/** Helper: prepares for a readv/WSARecv call by expanding the buffer to
+ * hold enough memory to read 'howmuch' bytes in possibly noncontiguous memory.
+ * Sets up the one or two iovecs in 'vecs' to point to the free memory and its
+ * extent, and *chainp to point to the first chain that we'll try to read into.
+ * Returns the number of vecs used.
+ */
+int _evbuffer_read_setup_vecs(struct evbuffer *buf, ev_ssize_t howmuch,
+ struct evbuffer_iovec *vecs, int n_vecs, struct evbuffer_chain ***chainp,
+ int exact);
+
+/* Helper macro: copies an evbuffer_iovec in ei to a win32 WSABUF in i. */
+#define WSABUF_FROM_EVBUFFER_IOV(i,ei) do { \
+ (i)->buf = (ei)->iov_base; \
+ (i)->len = (unsigned long)(ei)->iov_len; \
+ } while (0)
+/* XXXX the cast above is safe for now, but not if we allow mmaps on win64.
+ * See note in buffer_iocp's launch_write function */
+
+/** Set the parent bufferevent object for buf to bev */
+void evbuffer_set_parent(struct evbuffer *buf, struct bufferevent *bev);
+
+void evbuffer_invoke_callbacks(struct evbuffer *buf);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _EVBUFFER_INTERNAL_H_ */