transmission/libtransmission/bandwidth.h

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/*
* This file Copyright (C) 2008 Charles Kerr <charles@rebelbase.com>
*
* This file is licensed by the GPL version 2. Works owned by the
* Transmission project are granted a special exemption to clause 2(b)
* so that the bulk of its code can remain under the MIT license.
* This exemption does not extend to derived works not owned by
* the Transmission project.
*
* $Id:$
*/
#ifndef __TRANSMISSION__
#error only libtransmission should #include this header.
#endif
#ifndef TR_BANDWIDTH_H
#define TR_BANDWIDTH_H
struct tr_iobuf;
/**
* Bandwidth is an object for measuring and constraining bandwidth speeds.
*
* Bandwidth objects can be "stacked" so that a peer can be made to obey
* multiple constraints (for example, obeying the global speed limit and a
* per-torrent speed limit).
*
* HIERARCHY
*
* Transmission's bandwidth hierarchy is a tree.
* At the top is the global bandwidth object owned by tr_session.
* Its children are per-torrent bandwidth objects owned by tr_torrent.
* Underneath those are per-peer bandwidth objects owned by tr_peer.
*
* tr_session also owns a tr_handshake's bandwidths, so that the handshake
* I/O can be counted in the global raw totals. When the handshake is done,
* the bandwidth's ownership passes to a tr_peer.
*
* MEASURING
*
* When you ask a bandwidth object for its speed, it gives the speed of the
* subtree underneath it as well. So you can get Transmission's overall
* speed by quering tr_session's bandwidth, per-torrent speeds by asking
* tr_torrent's bandwidth, and per-peer speeds by asking tr_peer's bandwidth.
*
* CONSTRAINING
*
* Call tr_bandwidthAllocate() periodically. tr_bandwidth knows its current
* speed and will decide how many bytes to make available over the
* user-specified period to reach the user-specified desired speed.
* If appropriate, it notifies its iobufs that new bandwidth is available.
*
* tr_bandwidthAllocate() operates on the tr_bandwidth subtree, so usually
* you'll only need to invoke it for the top-level tr_session bandwidth.
*
* The iobufs all have a pointer to their associated tr_bandwidth object,
* and call tr_bandwidthClamp() before performing I/O to see how much
* bandwidth they can safely use.
*/
typedef struct tr_bandwidth tr_bandwidth;
/**
***
**/
/** @brief create a new tr_bandwidth object */
tr_bandwidth*
tr_bandwidthNew ( tr_session * session,
tr_bandwidth * parent );
/** @brief destroy a tr_bandwidth object */
void tr_bandwidthFree ( tr_bandwidth * bandwidth );
/******
*******
******/
/**
* @brief Set the desired speed (in KiB/s) for this bandwidth subtree.
* @see tr_bandwidthAllocate
* @see tr_bandwidthGetDesiredSpeed
*/
void tr_bandwidthSetDesiredSpeed ( tr_bandwidth * bandwidth,
tr_direction direction,
double desiredSpeed );
/**
* @brief Get the desired speed (in KiB/s) for ths bandwidth subtree.
* @see tr_bandwidthSetDesiredSpeed
*/
double tr_bandwidthGetDesiredSpeed ( const tr_bandwidth * bandwidth,
tr_direction direction );
/**
* @brief Set whether or not this bandwidth should throttle its iobufs' speeds
*/
void tr_bandwidthSetLimited ( tr_bandwidth * bandwidth,
tr_direction direction,
int isLimited );
/**
* @return nonzero if this bandwidth throttles its iobufs' speeds
*/
int tr_bandwidthIsLimited ( const tr_bandwidth * bandwidth,
tr_direction direction );
/**
* @brief allocate the next period_msec's worth of bandwidth for the iobufs to consume
*/
void tr_bandwidthAllocate ( tr_bandwidth * bandwidth,
tr_direction direction,
int period_msec );
/**
* @brief clamps byteCount down to a number that this bandwidth will allow to be consumed
*/
size_t tr_bandwidthClamp ( const tr_bandwidth * bandwidth,
tr_direction direction,
size_t byteCount );
/******
*******
******/
/**
* @brief Get the raw total of bytes read or sent by this bandwidth subtree.
*/
double tr_bandwidthGetRawSpeed ( const tr_bandwidth * bandwidth,
tr_direction direction );
/**
* @brief Get the number of piece data bytes read or sent by this bandwidth subtree.
*/
double tr_bandwidthGetPieceSpeed ( const tr_bandwidth * bandwidth,
tr_direction direction );
/**
* @brief Notify the bandwidth object that some of its allocated bandwidth has been consumed.
* This is is usually invoked by the iobuf after a read or write.
*/
void tr_bandwidthUsed ( tr_bandwidth * bandwidth,
tr_direction direction,
size_t byteCount,
int isPieceData );
/******
*******
******/
void tr_bandwidthSetParent ( tr_bandwidth * bandwidth,
tr_bandwidth * parent );
/**
* Almost all the time we do want to honor a parents' bandwidth cap, so that
* (for example) a peer is constrained by a per-torrent cap and the global cap.
* But when we set a torrent's speed mode to TR_SPEEDLIMIT_UNLIMITED, then
* in that particular case we want to ignore the global speed limit...
*/
void tr_bandwidthHonorParentLimits ( tr_bandwidth * bandwidth,
tr_direction direction,
int isEnabled );
/******
*******
******/
/**
* @brief add an iobuf to this bandwidth's list of iobufs.
* They will be notified when more bandwidth is made available for them to consume.
*/
void tr_bandwidthAddBuffer ( tr_bandwidth * bandwidth,
struct tr_iobuf * iobuf );
/**
* @brief remove an iobuf from this bandwidth's list of iobufs.
*/
void tr_bandwidthRemoveBuffer ( tr_bandwidth * bandwidth,
struct tr_iobuf * iobuf );
#endif