Squashed 'third_party/libevent/' content from commit d8ceae8
Change-Id: I84e1b23561eb225b9f288717b028e6bc9e5a27e1
git-subtree-dir: third_party/libevent
git-subtree-split: d8ceae81b83f3d0a56e2f41d4c429b2702a8e302
diff --git a/bufferevent-internal.h b/bufferevent-internal.h
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+/*
+ * Copyright (c) 2008-2012 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 _BUFFEREVENT_INTERNAL_H_
+#define _BUFFEREVENT_INTERNAL_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "event2/event-config.h"
+#include "event2/util.h"
+#include "defer-internal.h"
+#include "evthread-internal.h"
+#include "event2/thread.h"
+#include "ratelim-internal.h"
+#include "event2/bufferevent_struct.h"
+
+/* These flags are reasons that we might be declining to actually enable
+ reading or writing on a bufferevent.
+ */
+
+/* On a all bufferevents, for reading: used when we have read up to the
+ watermark value.
+
+ On a filtering bufferevent, for writing: used when the underlying
+ bufferevent's write buffer has been filled up to its watermark
+ value.
+*/
+#define BEV_SUSPEND_WM 0x01
+/* On a base bufferevent: when we have emptied a bandwidth buckets */
+#define BEV_SUSPEND_BW 0x02
+/* On a base bufferevent: when we have emptied the group's bandwidth bucket. */
+#define BEV_SUSPEND_BW_GROUP 0x04
+/* On a socket bufferevent: can't do any operations while we're waiting for
+ * name lookup to finish. */
+#define BEV_SUSPEND_LOOKUP 0x08
+/* On a base bufferevent, for reading: used when a filter has choked this
+ * (underlying) bufferevent because it has stopped reading from it. */
+#define BEV_SUSPEND_FILT_READ 0x10
+
+typedef ev_uint16_t bufferevent_suspend_flags;
+
+struct bufferevent_rate_limit_group {
+ /** List of all members in the group */
+ TAILQ_HEAD(rlim_group_member_list, bufferevent_private) members;
+ /** Current limits for the group. */
+ struct ev_token_bucket rate_limit;
+ struct ev_token_bucket_cfg rate_limit_cfg;
+
+ /** True iff we don't want to read from any member of the group.until
+ * the token bucket refills. */
+ unsigned read_suspended : 1;
+ /** True iff we don't want to write from any member of the group.until
+ * the token bucket refills. */
+ unsigned write_suspended : 1;
+ /** True iff we were unable to suspend one of the bufferevents in the
+ * group for reading the last time we tried, and we should try
+ * again. */
+ unsigned pending_unsuspend_read : 1;
+ /** True iff we were unable to suspend one of the bufferevents in the
+ * group for writing the last time we tried, and we should try
+ * again. */
+ unsigned pending_unsuspend_write : 1;
+
+ /*@{*/
+ /** Total number of bytes read or written in this group since last
+ * reset. */
+ ev_uint64_t total_read;
+ ev_uint64_t total_written;
+ /*@}*/
+
+ /** The number of bufferevents in the group. */
+ int n_members;
+
+ /** The smallest number of bytes that any member of the group should
+ * be limited to read or write at a time. */
+ ev_ssize_t min_share;
+ ev_ssize_t configured_min_share;
+
+ /** Timeout event that goes off once a tick, when the bucket is ready
+ * to refill. */
+ struct event master_refill_event;
+ /** Lock to protect the members of this group. This lock should nest
+ * within every bufferevent lock: if you are holding this lock, do
+ * not assume you can lock another bufferevent. */
+ void *lock;
+};
+
+/** Fields for rate-limiting a single bufferevent. */
+struct bufferevent_rate_limit {
+ /* Linked-list elements for storing this bufferevent_private in a
+ * group.
+ *
+ * Note that this field is supposed to be protected by the group
+ * lock */
+ TAILQ_ENTRY(bufferevent_private) next_in_group;
+ /** The rate-limiting group for this bufferevent, or NULL if it is
+ * only rate-limited on its own. */
+ struct bufferevent_rate_limit_group *group;
+
+ /* This bufferevent's current limits. */
+ struct ev_token_bucket limit;
+ /* Pointer to the rate-limit configuration for this bufferevent.
+ * Can be shared. XXX reference-count this? */
+ struct ev_token_bucket_cfg *cfg;
+
+ /* Timeout event used when one this bufferevent's buckets are
+ * empty. */
+ struct event refill_bucket_event;
+};
+
+/** Parts of the bufferevent structure that are shared among all bufferevent
+ * types, but not exposed in bufferevent_struct.h. */
+struct bufferevent_private {
+ /** The underlying bufferevent structure. */
+ struct bufferevent bev;
+
+ /** Evbuffer callback to enforce watermarks on input. */
+ struct evbuffer_cb_entry *read_watermarks_cb;
+
+ /** If set, we should free the lock when we free the bufferevent. */
+ unsigned own_lock : 1;
+
+ /** Flag: set if we have deferred callbacks and a read callback is
+ * pending. */
+ unsigned readcb_pending : 1;
+ /** Flag: set if we have deferred callbacks and a write callback is
+ * pending. */
+ unsigned writecb_pending : 1;
+ /** Flag: set if we are currently busy connecting. */
+ unsigned connecting : 1;
+ /** Flag: set if a connect failed prematurely; this is a hack for
+ * getting around the bufferevent abstraction. */
+ unsigned connection_refused : 1;
+ /** Set to the events pending if we have deferred callbacks and
+ * an events callback is pending. */
+ short eventcb_pending;
+
+ /** If set, read is suspended until one or more conditions are over.
+ * The actual value here is a bitfield of those conditions; see the
+ * BEV_SUSPEND_* flags above. */
+ bufferevent_suspend_flags read_suspended;
+
+ /** If set, writing is suspended until one or more conditions are over.
+ * The actual value here is a bitfield of those conditions; see the
+ * BEV_SUSPEND_* flags above. */
+ bufferevent_suspend_flags write_suspended;
+
+ /** Set to the current socket errno if we have deferred callbacks and
+ * an events callback is pending. */
+ int errno_pending;
+
+ /** The DNS error code for bufferevent_socket_connect_hostname */
+ int dns_error;
+
+ /** Used to implement deferred callbacks */
+ struct deferred_cb deferred;
+
+ /** The options this bufferevent was constructed with */
+ enum bufferevent_options options;
+
+ /** Current reference count for this bufferevent. */
+ int refcnt;
+
+ /** Lock for this bufferevent. Shared by the inbuf and the outbuf.
+ * If NULL, locking is disabled. */
+ void *lock;
+
+ /** Rate-limiting information for this bufferevent */
+ struct bufferevent_rate_limit *rate_limiting;
+};
+
+/** Possible operations for a control callback. */
+enum bufferevent_ctrl_op {
+ BEV_CTRL_SET_FD,
+ BEV_CTRL_GET_FD,
+ BEV_CTRL_GET_UNDERLYING,
+ BEV_CTRL_CANCEL_ALL
+};
+
+/** Possible data types for a control callback */
+union bufferevent_ctrl_data {
+ void *ptr;
+ evutil_socket_t fd;
+};
+
+/**
+ Implementation table for a bufferevent: holds function pointers and other
+ information to make the various bufferevent types work.
+*/
+struct bufferevent_ops {
+ /** The name of the bufferevent's type. */
+ const char *type;
+ /** At what offset into the implementation type will we find a
+ bufferevent structure?
+
+ Example: if the type is implemented as
+ struct bufferevent_x {
+ int extra_data;
+ struct bufferevent bev;
+ }
+ then mem_offset should be offsetof(struct bufferevent_x, bev)
+ */
+ off_t mem_offset;
+
+ /** Enables one or more of EV_READ|EV_WRITE on a bufferevent. Does
+ not need to adjust the 'enabled' field. Returns 0 on success, -1
+ on failure.
+ */
+ int (*enable)(struct bufferevent *, short);
+
+ /** Disables one or more of EV_READ|EV_WRITE on a bufferevent. Does
+ not need to adjust the 'enabled' field. Returns 0 on success, -1
+ on failure.
+ */
+ int (*disable)(struct bufferevent *, short);
+
+ /** Free any storage and deallocate any extra data or structures used
+ in this implementation.
+ */
+ void (*destruct)(struct bufferevent *);
+
+ /** Called when the timeouts on the bufferevent have changed.*/
+ int (*adj_timeouts)(struct bufferevent *);
+
+ /** Called to flush data. */
+ int (*flush)(struct bufferevent *, short, enum bufferevent_flush_mode);
+
+ /** Called to access miscellaneous fields. */
+ int (*ctrl)(struct bufferevent *, enum bufferevent_ctrl_op, union bufferevent_ctrl_data *);
+
+};
+
+extern const struct bufferevent_ops bufferevent_ops_socket;
+extern const struct bufferevent_ops bufferevent_ops_filter;
+extern const struct bufferevent_ops bufferevent_ops_pair;
+
+#define BEV_IS_SOCKET(bevp) ((bevp)->be_ops == &bufferevent_ops_socket)
+#define BEV_IS_FILTER(bevp) ((bevp)->be_ops == &bufferevent_ops_filter)
+#define BEV_IS_PAIR(bevp) ((bevp)->be_ops == &bufferevent_ops_pair)
+
+#ifdef WIN32
+extern const struct bufferevent_ops bufferevent_ops_async;
+#define BEV_IS_ASYNC(bevp) ((bevp)->be_ops == &bufferevent_ops_async)
+#else
+#define BEV_IS_ASYNC(bevp) 0
+#endif
+
+/** Initialize the shared parts of a bufferevent. */
+int bufferevent_init_common(struct bufferevent_private *, struct event_base *, const struct bufferevent_ops *, enum bufferevent_options options);
+
+/** For internal use: temporarily stop all reads on bufev, until the conditions
+ * in 'what' are over. */
+void bufferevent_suspend_read(struct bufferevent *bufev, bufferevent_suspend_flags what);
+/** For internal use: clear the conditions 'what' on bufev, and re-enable
+ * reading if there are no conditions left. */
+void bufferevent_unsuspend_read(struct bufferevent *bufev, bufferevent_suspend_flags what);
+
+/** For internal use: temporarily stop all writes on bufev, until the conditions
+ * in 'what' are over. */
+void bufferevent_suspend_write(struct bufferevent *bufev, bufferevent_suspend_flags what);
+/** For internal use: clear the conditions 'what' on bufev, and re-enable
+ * writing if there are no conditions left. */
+void bufferevent_unsuspend_write(struct bufferevent *bufev, bufferevent_suspend_flags what);
+
+#define bufferevent_wm_suspend_read(b) \
+ bufferevent_suspend_read((b), BEV_SUSPEND_WM)
+#define bufferevent_wm_unsuspend_read(b) \
+ bufferevent_unsuspend_read((b), BEV_SUSPEND_WM)
+
+/*
+ Disable a bufferevent. Equivalent to bufferevent_disable(), but
+ first resets 'connecting' flag to force EV_WRITE down for sure.
+
+ XXXX this method will go away in the future; try not to add new users.
+ See comment in evhttp_connection_reset() for discussion.
+
+ @param bufev the bufferevent to be disabled
+ @param event any combination of EV_READ | EV_WRITE.
+ @return 0 if successful, or -1 if an error occurred
+ @see bufferevent_disable()
+ */
+int bufferevent_disable_hard(struct bufferevent *bufev, short event);
+
+/** Internal: Set up locking on a bufferevent. If lock is set, use it.
+ * Otherwise, use a new lock. */
+int bufferevent_enable_locking(struct bufferevent *bufev, void *lock);
+/** Internal: Increment the reference count on bufev. */
+void bufferevent_incref(struct bufferevent *bufev);
+/** Internal: Lock bufev and increase its reference count.
+ * unlocking it otherwise. */
+void _bufferevent_incref_and_lock(struct bufferevent *bufev);
+/** Internal: Decrement the reference count on bufev. Returns 1 if it freed
+ * the bufferevent.*/
+int bufferevent_decref(struct bufferevent *bufev);
+/** Internal: Drop the reference count on bufev, freeing as necessary, and
+ * unlocking it otherwise. Returns 1 if it freed the bufferevent. */
+int _bufferevent_decref_and_unlock(struct bufferevent *bufev);
+
+/** Internal: If callbacks are deferred and we have a read callback, schedule
+ * a readcb. Otherwise just run the readcb. */
+void _bufferevent_run_readcb(struct bufferevent *bufev);
+/** Internal: If callbacks are deferred and we have a write callback, schedule
+ * a writecb. Otherwise just run the writecb. */
+void _bufferevent_run_writecb(struct bufferevent *bufev);
+/** Internal: If callbacks are deferred and we have an eventcb, schedule
+ * it to run with events "what". Otherwise just run the eventcb. */
+void _bufferevent_run_eventcb(struct bufferevent *bufev, short what);
+
+/** Internal: Add the event 'ev' with timeout tv, unless tv is set to 0, in
+ * which case add ev with no timeout. */
+int _bufferevent_add_event(struct event *ev, const struct timeval *tv);
+
+/* =========
+ * These next functions implement timeouts for bufferevents that aren't doing
+ * anything else with ev_read and ev_write, to handle timeouts.
+ * ========= */
+/** Internal use: Set up the ev_read and ev_write callbacks so that
+ * the other "generic_timeout" functions will work on it. Call this from
+ * the constructor function. */
+void _bufferevent_init_generic_timeout_cbs(struct bufferevent *bev);
+/** Internal use: Delete the ev_read and ev_write callbacks if they're pending.
+ * Call this from the destructor function. */
+int _bufferevent_del_generic_timeout_cbs(struct bufferevent *bev);
+/** Internal use: Add or delete the generic timeout events as appropriate.
+ * (If an event is enabled and a timeout is set, we add the event. Otherwise
+ * we delete it.) Call this from anything that changes the timeout values,
+ * that enabled EV_READ or EV_WRITE, or that disables EV_READ or EV_WRITE. */
+int _bufferevent_generic_adj_timeouts(struct bufferevent *bev);
+
+/** Internal use: We have just successfully read data into an inbuf, so
+ * reset the read timeout (if any). */
+#define BEV_RESET_GENERIC_READ_TIMEOUT(bev) \
+ do { \
+ if (evutil_timerisset(&(bev)->timeout_read)) \
+ event_add(&(bev)->ev_read, &(bev)->timeout_read); \
+ } while (0)
+/** Internal use: We have just successfully written data from an inbuf, so
+ * reset the read timeout (if any). */
+#define BEV_RESET_GENERIC_WRITE_TIMEOUT(bev) \
+ do { \
+ if (evutil_timerisset(&(bev)->timeout_write)) \
+ event_add(&(bev)->ev_write, &(bev)->timeout_write); \
+ } while (0)
+#define BEV_DEL_GENERIC_READ_TIMEOUT(bev) \
+ event_del(&(bev)->ev_read)
+#define BEV_DEL_GENERIC_WRITE_TIMEOUT(bev) \
+ event_del(&(bev)->ev_write)
+
+
+/** Internal: Given a bufferevent, return its corresponding
+ * bufferevent_private. */
+#define BEV_UPCAST(b) EVUTIL_UPCAST((b), struct bufferevent_private, bev)
+
+#ifdef _EVENT_DISABLE_THREAD_SUPPORT
+#define BEV_LOCK(b) _EVUTIL_NIL_STMT
+#define BEV_UNLOCK(b) _EVUTIL_NIL_STMT
+#else
+/** Internal: Grab the lock (if any) on a bufferevent */
+#define BEV_LOCK(b) do { \
+ struct bufferevent_private *locking = BEV_UPCAST(b); \
+ EVLOCK_LOCK(locking->lock, 0); \
+ } while (0)
+
+/** Internal: Release the lock (if any) on a bufferevent */
+#define BEV_UNLOCK(b) do { \
+ struct bufferevent_private *locking = BEV_UPCAST(b); \
+ EVLOCK_UNLOCK(locking->lock, 0); \
+ } while (0)
+#endif
+
+
+/* ==== For rate-limiting. */
+
+int _bufferevent_decrement_write_buckets(struct bufferevent_private *bev,
+ ev_ssize_t bytes);
+int _bufferevent_decrement_read_buckets(struct bufferevent_private *bev,
+ ev_ssize_t bytes);
+ev_ssize_t _bufferevent_get_read_max(struct bufferevent_private *bev);
+ev_ssize_t _bufferevent_get_write_max(struct bufferevent_private *bev);
+
+#ifdef __cplusplus
+}
+#endif
+
+
+#endif /* _BUFFEREVENT_INTERNAL_H_ */