296 lines
9.4 KiB
C
296 lines
9.4 KiB
C
/******************************************************************************
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* $Id$
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*
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* Copyright (c) 2005-2007 Transmission authors and contributors
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*****************************************************************************/
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static int peerCmp( tr_peer_t * peer1, tr_peer_t * peer2 )
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{
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/* Wait until we got the peers' ids */
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if( peer1->status <= PEER_STATUS_HANDSHAKE ||
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peer2->status <= PEER_STATUS_HANDSHAKE )
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{
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return 1;
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}
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return memcmp( peer1->id, peer2->id, 20 );
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}
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static int
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checkPeer( tr_peer_t * peer )
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{
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int ret;
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tr_torrent * tor = peer->tor;
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const uint64_t now = tr_date( );
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const uint64_t idleTime = now - peer->date;
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const uint64_t idleSecs = idleTime / 1000u;
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uint64_t lo, hi, limit;
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int relaxStrictnessIfFewerThanN;
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double strictness;
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/* when deciding whether or not to keep a peer, judge its responsiveness
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on a sliding scale that's based on how many other peers are available */
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relaxStrictnessIfFewerThanN =
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(int)(((TR_MAX_PEER_COUNT * PERCENT_PEER_WANTED) / 100.0) + 0.5);
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/* if we have >= relaxIfFewerThan, strictness is 100%.
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if we have zero connections, strictness is 0% */
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if( tor->peerCount >= relaxStrictnessIfFewerThanN )
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strictness = 1.0;
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else
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strictness = tor->peerCount / (double)relaxStrictnessIfFewerThanN;
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/* test: has it been too long since we were properly connected to them? */
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lo = MIN_CON_TIMEOUT;
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hi = MAX_CON_TIMEOUT;
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limit = lo + ((hi-lo) * strictness);
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if( peer->status < PEER_STATUS_CONNECTED && idleTime > limit ) {
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peer_dbg( "connection timeout, idled %"PRIu64" seconds", idleSecs );
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return TR_ERROR;
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}
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/* test: have we been waiting on a request for too long? */
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lo = MIN_UPLOAD_IDLE;
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hi = MAX_UPLOAD_IDLE;
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limit = lo + ((hi-lo) * strictness);
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if( peer->inRequestCount && idleTime > limit ) {
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peer_dbg( "idle uploader timeout, idled %"PRIu64" seconds", idleSecs );
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return TR_ERROR;
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}
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/* test: has it been too long since the peer gave us any response at all? */
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lo = MIN_KEEP_ALIVE;
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hi = MAX_KEEP_ALIVE;
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limit = lo + ((hi-lo) * strictness);
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if( idleTime > limit ) {
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peer_dbg( "peer timeout, idled %"PRIu64" seconds", idleSecs );
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return TR_ERROR;
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}
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if( PEER_STATUS_CONNECTED == peer->status )
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{
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/* Send keep-alive every 1 minute and 45 seconds */
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if( now > peer->keepAlive + 105000 )
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{
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sendKeepAlive( peer );
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peer->keepAlive = now;
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}
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/* Resend extended handshake if our public port changed */
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if( EXTENDED_HANDSHAKE == peer->extStatus &&
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tor->publicPort != peer->advertisedPort )
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{
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sendExtended( tor, peer, EXTENDED_HANDSHAKE_ID );
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}
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/* Send peer list */
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if( !peer->private && 0 < peer->pexStatus )
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{
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if( 0 == peer->lastPex )
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{
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/* randomize time when first pex message is sent */
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peer->lastPex = now - 1000 * tr_rand( PEX_INTERVAL );
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}
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if( now > peer->lastPex + 1000 * PEX_INTERVAL )
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{
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if( EXTENDED_HANDSHAKE == peer->extStatus )
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{
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ret = sendExtended( tor, peer, EXTENDED_PEX_ID );
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}
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else if( peer->azproto )
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{
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ret = sendAZPex( tor, peer );
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}
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else
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{
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assert( 0 );
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ret = TR_ERROR;
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}
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if( ret )
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{
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return ret;
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}
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peer->lastPex = now + 1000 *
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( PEX_INTERVAL + tr_rand( PEX_INTERVAL / 10 ) );
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}
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}
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}
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return TR_OK;
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}
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static int isPieceInteresting( const tr_torrent * tor,
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const tr_peer_t * peer,
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int piece )
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{
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if( tor->info.pieces[piece].dnd ) /* we don't want it */
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return 0;
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if( tr_cpPieceIsComplete( tor->completion, piece ) ) /* we already have it */
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return 0;
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if( !tr_bitfieldHas( peer->bitfield, piece ) ) /* peer doesn't have it */
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return 0;
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if( tr_bitfieldHas( peer->banfield, piece ) ) /* peer is banned for it */
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return 0;
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return 1;
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}
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/***********************************************************************
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* isInteresting
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***********************************************************************
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* Returns 1 if 'peer' has at least one piece that we want but
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* haven't completed, or 0 otherwise.
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**********************************************************************/
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static int isInteresting( const tr_torrent * tor, const tr_peer_t * peer )
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{
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int i;
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const tr_bitfield * bitfield = tr_cpPieceBitfield( tor->completion );
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if( !peer->bitfield )
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{
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/* We don't know what this peer has */
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return 0;
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}
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assert( bitfield->len == peer->bitfield->len );
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for( i=0; i<tor->info.pieceCount; ++i )
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if( isPieceInteresting( tor, peer, i ) )
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return 1;
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return 0;
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}
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static void
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updateInterest( tr_torrent * tor, tr_peer_t * peer )
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{
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const int i = !!isInteresting( tor, peer );
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if( i != peer->isInteresting )
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sendInterest( peer, i );
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}
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/** utility structure used by getPreferredPieces() and comparePieces() */
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typedef struct
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{
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int piece;
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tr_priority_t priority;
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int missingBlockCount;
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int peerCount;
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}
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PieceCompareData;
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/** utility function used by getPreferredPieces */
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int comparePieces (const void * aIn, const void * bIn)
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{
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const PieceCompareData * a = (const PieceCompareData*) aIn;
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const PieceCompareData * b = (const PieceCompareData*) bIn;
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/* if one piece has a higher priority, it goes first */
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if (a->priority != b->priority)
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return a->priority > b->priority ? -1 : 1;
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/* otherwise if one has fewer missing blocks, it goes first */
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if (a->missingBlockCount != b->missingBlockCount)
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return a->missingBlockCount < b->missingBlockCount ? -1 : 1;
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/* otherwise if one has fewer peers, it goes first */
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if (a->peerCount != b->peerCount)
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return a->peerCount < b->peerCount ? -1 : 1;
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/* otherwise go with the earlier piece */
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return a->piece - b->piece;
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}
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static int* getPreferredPieces( const tr_torrent * tor,
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const tr_peer_t * peer,
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int * pieceCount,
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int * isEndgame )
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{
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const tr_info * inf = &tor->info;
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int i;
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int poolSize = 0;
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int endgame = FALSE;
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int * pool = tr_new( int, inf->pieceCount );
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for( i=0; i<inf->pieceCount; ++i )
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if( isPieceInteresting( tor, peer, i ) )
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if( tr_cpMissingBlocksForPiece( tor->completion, i ) )
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pool[poolSize++] = i;
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if( !poolSize ) {
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endgame = TRUE;
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for( i=0; i<inf->pieceCount; ++i )
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if( isPieceInteresting( tor, peer, i ) )
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pool[poolSize++] = i;
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}
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#if 0
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fprintf (stderr, "old pool: ");
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for (i=0; i<15 && i<poolSize; ++i ) fprintf (stderr, "%d, ", pool[i] );
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fprintf (stderr, "\n");
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#endif
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/* sort the rest from most interesting to least...
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but not in endgame, because it asks for pieces in a
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scattershot manner anyway and doesn't need them sorted */
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if( !endgame && ( poolSize > 1 ) )
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{
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PieceCompareData * p = tr_new( PieceCompareData, poolSize );
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for( i=0; i<poolSize; ++i )
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{
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int j;
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const int piece = pool[i];
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p[i].piece = piece;
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p[i].priority = inf->pieces[piece].priority;
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p[i].missingBlockCount = tr_cpMissingBlocksForPiece( tor->completion, piece );
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p[i].peerCount = 0;
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for( j=0; j<tor->peerCount; ++j )
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if( tr_bitfieldHas( tor->peers[j]->bitfield, piece ) )
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++p[i].peerCount;
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}
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qsort (p, poolSize, sizeof(PieceCompareData), comparePieces);
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for( i=0; i<poolSize; ++i )
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pool[i] = p[i].piece;
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tr_free( p );
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}
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#if 0
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fprintf (stderr, "new pool: ");
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for (i=0; i<15 && i<poolSize; ++i ) fprintf (stderr, "%d, ", pool[i] );
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fprintf (stderr, "\n");
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#endif
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*isEndgame = endgame;
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*pieceCount = poolSize;
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return pool;
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}
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