The Tor Browser: ipc/chromium/src/third_party/libevent/evbuffer-internal.h@6474c204b198 (annotated)

ipc/chromium/src/third_party/libevent/evbuffer-internal.h@6474c204b198 (annotated)

ipc/chromium/src/third_party/libevent/evbuffer-internal.h

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /*
  * 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;
 };
 /** 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_off_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_ */

The Tor Browser / annotate

ipc/chromium/src/third_party/libevent/evbuffer-internal.h@6474c204b198 (annotated)

ipc/chromium/src/third_party/libevent/evbuffer-internal.h