transmission/libtransmission/torrent.c

/******************************************************************************
 * $Id$
 *
 * Copyright (c) 2005-2007 Transmission authors and contributors
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *****************************************************************************/

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <sys/types.h>

#include "transmission.h"
#include "completion.h"
#include "crypto.h" /* for tr_sha1 */
#include "fastresume.h"
#include "handshake.h"
#include "inout.h"
#include "metainfo.h"
#include "net.h" /* tr_netNtop */
#include "peer-mgr.h"
#include "platform.h"
#include "ratecontrol.h"
#include "shared.h"
#include "tracker.h"
#include "trcompat.h" /* for strlcpy */
#include "trevent.h"
#include "utils.h"

/***
****
***/

int
tr_torrentExists( tr_handle       * handle,
                  const uint8_t   * torrentHash )
{
    return tr_torrentFindFromHash( handle, torrentHash ) != NULL;
}

tr_torrent*
tr_torrentFindFromHash( tr_handle      * handle,
                        const uint8_t  * torrentHash )
{
    tr_torrent * tor;

    for( tor = handle->torrentList; tor; tor = tor->next )
        if( !memcmp( tor->info.hash, torrentHash, SHA_DIGEST_LENGTH ) )
            return tor;

    return NULL;
}

tr_torrent*
tr_torrentFindFromObfuscatedHash( tr_handle      * handle,
                                  const uint8_t  * obfuscatedTorrentHash )
{
    tr_torrent * tor;

    for( tor = handle->torrentList; tor; tor = tor->next )
        if( !memcmp( tor->obfuscatedHash, obfuscatedTorrentHash, SHA_DIGEST_LENGTH ) )
            return tor;

    return NULL;
}

/***
****  LOCKS
***/

void
tr_torrentLock( const tr_torrent * tor )
{
    tr_lockLock ( (tr_lock*)tor->lock );
}

void
tr_torrentUnlock( const tr_torrent * tor )
{
    tr_lockUnlock ( (tr_lock*)tor->lock );
}

/***
****  PER-TORRENT UL / DL SPEEDS
***/

void
tr_torrentSetSpeedMode( tr_torrent   * tor,
                        int            up_or_down,
                        tr_speedlimit  mode )
{
    tr_speedlimit * limit = up_or_down==TR_UP
        ? &tor->uploadLimitMode
        : &tor->downloadLimitMode;
    *limit = mode;
}

tr_speedlimit
tr_torrentGetSpeedMode( const tr_torrent * tor,
                        int                up_or_down)
{
    return up_or_down==TR_UP ? tor->uploadLimitMode
                             : tor->downloadLimitMode;
}

void
tr_torrentSetSpeedLimit( tr_torrent   * tor,
                         int            up_or_down,
                         int            single_KiB_sec )
{
    tr_ratecontrol * rc = up_or_down==TR_UP ? tor->upload : tor->download;
    tr_rcSetLimit( rc, single_KiB_sec );
}

int
tr_torrentGetSpeedLimit( const tr_torrent  * tor,
                         int                 up_or_down )
{
    tr_ratecontrol * rc = up_or_down==TR_UP ? tor->upload : tor->download;
    return tr_rcGetLimit( rc );
}

/***
****
***/

static void
onTrackerResponse( void * tracker UNUSED, void * vevent, void * user_data )
{
    tr_torrent * tor = (tr_torrent *) user_data;
    tr_tracker_event_t * event = (tr_tracker_event_t *) vevent;

    switch( event->messageType )
    {
        case TR_TRACKER_PEERS:
            tr_peerMgrAddPeers( tor->handle->peerMgr,
                                tor->info.hash,
                                TR_PEER_FROM_TRACKER,
                                event->peerCompact,
                                event->peerCount );
            break;

        case TR_TRACKER_WARNING:
            tr_err( "Tracker: Warning - %s", event->text );
            tor->error = TR_ERROR_TC_WARNING;
            strlcpy( tor->errorString, event->text, sizeof(tor->errorString) );
            break;

        case TR_TRACKER_ERROR:
            tr_err( "Tracker: Error - %s", event->text );
            tor->error = TR_ERROR_TC_ERROR;
            strlcpy( tor->errorString, event->text, sizeof(tor->errorString) );
            break;

        case TR_TRACKER_ERROR_CLEAR:
            tor->error = 0;
            tor->errorString[0] = '\0';
            break;

        case TR_TRACKER_STOPPED:
            //assert( tor->runStatus == TR_RUN_STOPPING );
            tor->runStatus = TR_RUN_STOPPED;
            break;
    }
}

/***
****
****  TORRENT INSTANTIATION
****
***/

static int
getBytePiece( const tr_info * info, uint64_t byteOffset )
{
    assert( info != NULL );
    assert( info->pieceSize != 0 );

    return byteOffset / info->pieceSize;
}

static void
initFilePieces ( tr_info * info, int fileIndex )
{
    tr_file * file = &info->files[fileIndex];
    uint64_t firstByte, lastByte;

    assert( info != NULL );
    assert( 0<=fileIndex && fileIndex<info->fileCount );

    file = &info->files[fileIndex];
    firstByte = file->offset;
    lastByte = firstByte + (file->length ? file->length-1 : 0);
    file->firstPiece = getBytePiece( info, firstByte );
    file->lastPiece = getBytePiece( info, lastByte );
}

static tr_priority_t
calculatePiecePriority ( const tr_torrent * tor,
                         int                piece )
{
    int i;
    tr_priority_t priority = TR_PRI_NORMAL;

    for( i=0; i<tor->info.fileCount; ++i )
    {
        const tr_file * file = &tor->info.files[i];
        if ( file->firstPiece <= piece
          && file->lastPiece  >= piece
          && file->priority   >  priority)
              priority = file->priority;

        /* when dealing with multimedia files, getting the first and
           last pieces can sometimes allow you to preview it a bit
           before it's fully downloaded... */
        if ( file->priority >= TR_PRI_NORMAL )
            if ( file->firstPiece == piece || file->lastPiece == piece )
                priority = TR_PRI_HIGH;
    }

    return priority;
}

static void
tr_torrentInitFilePieces( tr_torrent * tor )
{
    int i;
    uint64_t offset = 0;

    assert( tor != NULL );

    for( i=0; i<tor->info.fileCount; ++i ) {
      tor->info.files[i].offset = offset;
      offset += tor->info.files[i].length;
      initFilePieces( &tor->info, i );
    }

    for( i=0; i<tor->info.pieceCount; ++i )
        tor->info.pieces[i].priority = calculatePiecePriority( tor, i );
}

static void
tr_torrentStartImpl( tr_torrent * tor )
{
    assert( tor != NULL );
    assert( tor->runStatus == TR_RUN_RUNNING );

    *tor->errorString = '\0';
    tr_torrentResetTransferStats( tor );
    tr_torrentRecheckCompleteness( tor );
    tor->startDate = tr_date();
    tr_trackerStart( tor->tracker );
    tr_peerMgrStartTorrent( tor->handle->peerMgr, tor->info.hash );
}

static void
recheckDoneCB( tr_torrent * tor )
{
    tr_torrentRecheckCompleteness( tor );

    if( tor->doStopAfterHashCheck ) {
        tor->doStopAfterHashCheck = 0;
        tr_torrentStop( tor );
    }

    if( tor->runStatus == TR_RUN_RUNNING )
        tr_torrentStartImpl( tor );
}

static void
torrentRealInit( tr_handle  * h,
                 tr_torrent * tor,
                 const char * destination,
                 int          flags )
{
    uint64_t loaded;
    uint64_t t;
    tr_bitfield * uncheckedPieces;
    tr_info * info = &tor->info;
    
    tor->info.flags |= flags;

    tr_sharedLock( h->shared );

    tor->destination = tr_strdup( destination );

    tor->handle   = h;
    tor->hasChangedState = -1;
    tor->pexDisabled = 0;

    tor->runStatusToSaveIsSet = FALSE;

    /**
     * Decide on a block size.  constraints:
     * (1) most clients decline requests over 16 KiB
     * (2) pieceSize must be a multiple of block size
     */
    tor->blockSize = info->pieceSize;
    while( tor->blockSize > (1024*16) )
        tor->blockSize /= 2;

    tor->lastPieceSize = info->totalSize % info->pieceSize;

    if( !tor->lastPieceSize )
         tor->lastPieceSize = info->pieceSize;

    tor->lastBlockSize = info->totalSize % tor->blockSize;

    if( !tor->lastBlockSize )
         tor->lastBlockSize = tor->blockSize;

    tor->blockCount =
        ( info->totalSize + tor->blockSize - 1 ) / tor->blockSize;

    tor->blockCountInPiece =
        info->pieceSize / tor->blockSize;

    tor->blockCountInLastPiece =
        ( tor->lastPieceSize + tor->blockSize - 1 ) / tor->blockSize;

    /* check our work */
    assert( ( info->pieceSize % tor->blockSize ) == 0 );
    t = info->pieceCount - 1;
    t *= info->pieceSize;
    t += tor->lastPieceSize;
    assert( t == info->totalSize );
    t = tor->blockCount - 1;
    t *= tor->blockSize;
    t += tor->lastBlockSize;
    assert( t == info->totalSize );
    t = info->pieceCount - 1;
    t *= tor->blockCountInPiece;
    t += tor->blockCountInLastPiece;
    assert( t == (uint64_t)tor->blockCount );

    tor->completion = tr_cpInit( tor );

    tr_torrentInitFilePieces( tor );

    tor->lock = tr_lockNew( );

    tor->upload         = tr_rcInit();
    tor->download       = tr_rcInit();
    tor->swarmspeed     = tr_rcInit();

    tr_sha1( tor->obfuscatedHash, "req2", 4,
                                  info->hash, SHA_DIGEST_LENGTH,
                                  NULL );
 
    tr_sharedUnlock( h->shared );

    tr_peerMgrAddTorrent( h->peerMgr, tor );

    if( !h->isPortSet )
        tr_setBindPort( h, TR_DEFAULT_PORT );

    assert( !tor->downloadedCur );
    assert( !tor->uploadedCur );

    tor->error   = TR_OK;

    uncheckedPieces = tr_bitfieldNew( tor->info.pieceCount );
    loaded = tr_fastResumeLoad( tor, uncheckedPieces );

    /* the `paused' flag has highest precedence...
       after that, the fastresume setting is used...
       if that's not found, default to RUNNING */
    if( flags & TR_FLAG_PAUSED )
        tor->runStatus = TR_RUN_STOPPED;
    else if( !(loaded & TR_FR_RUN ) )
        tor->runStatus = TR_RUN_RUNNING;

    if( tr_bitfieldIsEmpty( uncheckedPieces ) )
        tr_bitfieldFree( uncheckedPieces );
    else
        tor->uncheckedPieces = uncheckedPieces;


    if( !(loaded & TR_FR_SPEEDLIMIT ) ) {
        int limit, enabled;
        tr_getGlobalSpeedLimit( tor->handle, TR_UP, &enabled, &limit );
        tr_torrentSetSpeedLimit( tor, TR_UP, limit );
        tr_getGlobalSpeedLimit( tor->handle, TR_DOWN, &enabled, &limit );
        tr_torrentSetSpeedLimit( tor, TR_DOWN, limit );
    }

    tor->cpStatus = tr_cpGetStatus( tor->completion );

    tor->tracker = tr_trackerNew( tor );
    tor->trackerSubscription = tr_trackerSubscribe( tor->tracker, onTrackerResponse, tor );

    tr_sharedLock( h->shared );
    tor->next = h->torrentList;
    h->torrentList = tor;
    h->torrentCount++;
    tr_sharedUnlock( h->shared );

    tr_ioRecheckAdd( tor, recheckDoneCB, tor->runStatus );
}

static int
pathIsInUse ( const tr_handle   * h,
              const char        * destination,
              const char        * name )
{
    const tr_torrent * tor;
    
    for( tor=h->torrentList; tor; tor=tor->next )
        if( !strcmp( destination, tor->destination )
         && !strcmp( name, tor->info.name ) )
            return TRUE;

    return FALSE;
}

static int
hashExists( const tr_handle   * h,
            const uint8_t     * hash )
{
    const tr_torrent * tor;

    for( tor=h->torrentList; tor; tor=tor->next )
        if( !memcmp( hash, tor->info.hash, SHA_DIGEST_LENGTH ) )
            return TRUE;

    return FALSE;
}

static int
infoCanAdd( const tr_handle   * h,
            const char        * destination,
            const tr_info     * info )
{
    if( hashExists( h, info->hash ) )
        return TR_EDUPLICATE;

    if( destination && pathIsInUse( h, destination, info->name ) )
        return TR_EDUPLICATE;

    return TR_OK;
}

int
tr_torrentParse( const tr_handle  * h,
                 const char       * path,
                 const char       * destination,
                 tr_info          * setme_info )
{
    int ret, doFree;
    tr_info tmp;

    if( setme_info == NULL )
        setme_info = &tmp;

    memset( setme_info, 0, sizeof( tr_info ) );
    ret = tr_metainfoParseFile( setme_info, h->tag, path, FALSE );
    doFree = !ret && (setme_info == &tmp);

    if( ret == TR_OK )
        ret = infoCanAdd( h, destination, setme_info );

    if( doFree )
        tr_metainfoFree( &tmp );

    return ret;
}
 
tr_torrent *
tr_torrentInit( tr_handle   * h,
                const char  * path,
                const char  * destination,
                int           flags,
                int         * error )
{
    int val;
    int tmpError;
    tr_torrent * tor = NULL;

    if( !error )
         error = &tmpError;

    if(( val = tr_torrentParse( h, path, destination, NULL )))
        *error = val;
    else if(!(( tor = tr_new0( tr_torrent, 1 ))))
        *error = TR_EOTHER;
    else {
        tr_metainfoParseFile( &tor->info, h->tag, path, TR_FLAG_SAVE & flags );
        torrentRealInit( h, tor, destination, flags );
    }

    return tor;
}

int
tr_torrentParseHash( const tr_handle  * h,
                     const char       * hashStr,
                     const char       * destination,
                     tr_info          * setme_info )
{
    int ret, doFree;
    tr_info tmp;

    if( setme_info == NULL )
        setme_info = &tmp;

    memset( setme_info, 0, sizeof( tr_info ) );
    ret = tr_metainfoParseHash( setme_info, h->tag, hashStr );
    doFree = !ret && (setme_info == &tmp);

    if( ret == TR_OK )
        ret = infoCanAdd( h, destination, setme_info );

    if( doFree )
        tr_metainfoFree( &tmp );

    return ret;
}

tr_torrent *
tr_torrentInitSaved( tr_handle    * h,
                     const char   * hashStr,
                     const char   * destination,
                     int            flags,
                     int          * error )
{
    int val;
    int tmpError;
    tr_torrent * tor = NULL;

    if( !error )
         error = &tmpError;

    if(( val = tr_torrentParseHash( h, hashStr, destination, NULL )))
        *error = val;
    else if(!(( tor = tr_new0( tr_torrent, 1 ))))
        *error = TR_EOTHER;
    else {
        tr_metainfoParseHash( &tor->info, h->tag, hashStr );
        torrentRealInit( h, tor, destination, (TR_FLAG_SAVE|flags) );
    }

    return tor;
}

static int
tr_torrentParseData( const tr_handle  * h,
                     const uint8_t    * data,
                     size_t             size,
                     const char       * destination,
                     tr_info          * setme_info )
{
    int ret, doFree;
    tr_info tmp;

    if( setme_info == NULL )
        setme_info = &tmp;

    memset( setme_info, 0, sizeof( tr_info ) );
    ret = tr_metainfoParseData( setme_info, h->tag, data, size, FALSE );
    doFree = !ret && (setme_info == &tmp);

    if( ret == TR_OK )
        ret = infoCanAdd( h, destination, setme_info );

    if( doFree )
        tr_metainfoFree( &tmp );

    return ret;
}

tr_torrent *
tr_torrentInitData( tr_handle      * h,
                    const uint8_t  * data,
                    size_t           size,
                    const char     * destination,
                    int              flags,
                    int            * error )
{
    int val;
    int tmpError;
    tr_torrent * tor = NULL;

    if( !error )
         error = &tmpError;

    if(( val = tr_torrentParseData( h, data, size, destination, NULL )))
        *error = val;
    else if(!(( tor = tr_new0( tr_torrent, 1 ))))
        *error = TR_EOTHER;
    else {
        tr_metainfoParseData( &tor->info, h->tag, data, size, TR_FLAG_SAVE & flags );
        torrentRealInit( h, tor, destination, flags );
    }

    return tor;
}

const tr_info *
tr_torrentInfo( const tr_torrent * tor )
{
    return &tor->info;
}

/***
****
***/

#if 0
int tr_torrentScrape( tr_torrent * tor, int * s, int * l, int * d )
{
    return tr_trackerScrape( tor, s, l, d );
}
#endif

static int
saveFastResumeNow( void * vtor )
{
    tr_torrent * tor = (tr_torrent *) vtor;

    tr_fastResumeSave( tor );
    tr_torrentRecheckCompleteness( tor );

    tr_timerFree( &tor->saveTimer );
    return FALSE;
}

static void
saveFastResumeSoon( void * vtor )
{
    tr_torrent * tor = (tr_torrent *) vtor;

    if( tor->saveTimer == NULL )
        tor->saveTimer = tr_timerNew( tor->handle, saveFastResumeNow, tor, 100 );
}

/**
***
**/

void
tr_torrentSetFolder( tr_torrent * tor, const char * path )
{
    tr_free( tor->destination );
    tor->destination = tr_strdup( path );
    saveFastResumeSoon( tor );
}

const char*
tr_torrentGetFolder( const tr_torrent * tor )
{
    return tor->destination;
}

void
tr_torrentChangeMyPort( tr_torrent * tor )
{
    if( tor->tracker )
        tr_trackerChangeMyPort( tor->tracker );
}


void
tr_torrentDisablePex( tr_torrent * tor, int disable )
{
    assert( tor != NULL );
    assert( disable==0 || disable==1 );
    //assert( tor->runStatus != TR_RUN_RUNNING );

    /* pex is ALWAYS disabled for private torrents */
    if( tor->info.flags & TR_FLAG_PRIVATE )
        disable = TRUE;

    tor->pexDisabled = disable;
}

static int tr_didStateChangeTo ( tr_torrent * tor, int status )
{
    int ret;

    tr_torrentLock( tor );
    if (( ret = tor->hasChangedState == status ))
        tor->hasChangedState = -1;
    tr_torrentUnlock( tor );

    return ret;
}

int tr_getIncomplete( tr_torrent * tor )
{
    return tr_didStateChangeTo( tor, TR_CP_INCOMPLETE );
}
int tr_getDone( tr_torrent * tor )
{
    return tr_didStateChangeTo( tor, TR_CP_DONE );
}
int tr_getComplete( tr_torrent * tor )
{
    return tr_didStateChangeTo( tor, TR_CP_COMPLETE );
}

void
tr_manualUpdate( tr_torrent * tor )
{
    if( tor->runStatus == TR_RUN_RUNNING )
    tr_trackerReannounce( tor->tracker );
}
int
tr_torrentCanManualUpdate( const tr_torrent * tor )
{
    return ( tor != NULL )
        && ( tor->runStatus == TR_RUN_RUNNING )
        && ( tr_trackerCanManualAnnounce( tor->tracker ) );
}

const tr_stat *
tr_torrentStat( tr_torrent * tor )
{
    tr_stat * s;
    struct tr_tracker * tc;

    tr_torrentLock( tor );

    tor->statCur = !tor->statCur;
    s = &tor->stats[tor->statCur];

    s->error  = tor->error;
    memcpy( s->errorString, tor->errorString,
            sizeof( s->errorString ) );

    tc = tor->tracker;
    s->tracker = tr_trackerGetAddress( tor->tracker );

    tr_peerMgrTorrentStats( tor->handle->peerMgr,
                            tor->info.hash,
                            &s->peersTotal,
                            &s->peersConnected,
                            &s->peersSendingToUs,
                            &s->peersGettingFromUs,
                             s->peersFrom );

    s->percentComplete = tr_cpPercentComplete ( tor->completion );

    s->percentDone = tr_cpPercentDone( tor->completion );
    s->left = tr_cpLeftUntilDone( tor->completion );

    switch( tor->runStatus ) {
        case TR_RUN_CHECKING_WAIT: s->status = TR_STATUS_CHECK_WAIT; break;
        case TR_RUN_CHECKING: s->status = TR_STATUS_CHECK; break;
        case TR_RUN_STOPPING: s->status = TR_STATUS_STOPPING; break;
        case TR_RUN_STOPPED: s->status = TR_STATUS_STOPPED; break;
        case TR_RUN_RUNNING: switch( tor->cpStatus ) {
            case TR_CP_INCOMPLETE: s->status = TR_STATUS_DOWNLOAD; break;
            case TR_CP_DONE: s->status = TR_STATUS_DONE; break;
            case TR_CP_COMPLETE: s->status = TR_STATUS_SEED; break;
        }
    }

    s->recheckProgress = (tor->uncheckedPieces == NULL)
        ? 0.0
        : 1.0 - ((double)tr_bitfieldCountTrueBits(tor->uncheckedPieces) / tor->info.pieceCount);

    s->cpStatus = tor->cpStatus;

    /* tr_rcRate() doesn't make the difference between 'piece'
       messages and other messages, which causes a non-zero
       download rate even tough we are not downloading. So we
       force it to zero not to confuse the user. */
    s->rateDownload = tor->runStatus==TR_RUN_RUNNING 
        ? tr_rcRate( tor->download )
        : 0.0;
    s->rateUpload = tr_rcRate( tor->upload );
   
    tr_trackerGetCounts( tc,
                         &s->completedFromTracker,
                         &s->leechers, 
                         &s->seeders );

    s->swarmspeed = tr_rcRate( tor->swarmspeed );
    
    s->startDate = tor->startDate;
    s->activityDate = tor->activityDate;

    s->eta = s->rateDownload < 0.1
        ? -1.0f
        : (s->left / s->rateDownload / 1024.0);

    s->corrupt         = tor->corruptCur    + tor->corruptPrev;
    s->uploaded        = tor->uploadedCur   + tor->uploadedPrev;
    s->downloaded      = tor->downloadedCur + tor->downloadedPrev;
    s->downloadedValid = tr_cpDownloadedValid( tor->completion );
   
    s->ratio = s->downloaded || s->downloadedValid
      ? (float)s->uploaded / (float)MAX(s->downloaded, s->downloadedValid)
      : TR_RATIO_NA; 
    
    tr_torrentUnlock( tor );

    return s;
}

/***
****
***/

static uint64_t
fileBytesCompleted ( const tr_torrent * tor, int fileIndex )
{
    const tr_file * file     =  &tor->info.files[fileIndex];
    const uint64_t firstBlock       =  file->offset / tor->blockSize;
    const uint64_t firstBlockOffset =  file->offset % tor->blockSize;
    const uint64_t lastOffset       =  file->length ? (file->length-1) : 0;
    const uint64_t lastBlock        = (file->offset + lastOffset) / tor->blockSize;
    const uint64_t lastBlockOffset  = (file->offset + lastOffset) % tor->blockSize;
    uint64_t haveBytes = 0;

    assert( tor != NULL );
    assert( 0<=fileIndex && fileIndex<tor->info.fileCount );
    assert( file->offset + file->length <= tor->info.totalSize );
    assert( ( (int)firstBlock < tor->blockCount ) || (!file->length && file->offset==tor->info.totalSize) );
    assert( ( (int)lastBlock < tor->blockCount ) || (!file->length && file->offset==tor->info.totalSize) );
    assert( firstBlock <= lastBlock );
    assert( (int)tr_torBlockPiece( tor, firstBlock ) == file->firstPiece );
    assert( (int)tr_torBlockPiece( tor, lastBlock ) == file->lastPiece );

    if( firstBlock == lastBlock )
    {
        if( tr_cpBlockIsComplete( tor->completion, firstBlock ) )
            haveBytes += lastBlockOffset + 1 - firstBlockOffset;
    }
    else
    {
        uint64_t i;

        if( tr_cpBlockIsComplete( tor->completion, firstBlock ) )
            haveBytes += tor->blockSize - firstBlockOffset;

        for( i=firstBlock+1; i<lastBlock; ++i )
            if( tr_cpBlockIsComplete( tor->completion, i ) )
               haveBytes += tor->blockSize;

        if( tr_cpBlockIsComplete( tor->completion, lastBlock ) )
            haveBytes += lastBlockOffset + 1;
    }

    return haveBytes;
}

tr_file_stat *
tr_torrentFiles( const tr_torrent * tor, int * fileCount )
{
    int i;
    const int n = tor->info.fileCount;
    tr_file_stat * files = tr_new0( tr_file_stat, n );
    tr_file_stat * walk = files;

    for( i=0; i<n; ++i, ++walk )
    {
        const tr_file * file = tor->info.files + i;
        cp_status_t cp;

        walk->bytesCompleted = fileBytesCompleted( tor, i );

        walk->progress = file->length
            ? walk->bytesCompleted / (float)file->length
            : 1.0;

        if( walk->bytesCompleted >= file->length )
            cp = TR_CP_COMPLETE;
        else if( tor->info.files[i].dnd )
            cp = TR_CP_DONE;
        else
            cp = TR_CP_INCOMPLETE;

        walk->completionStatus = cp;
    }

    *fileCount = n;

    return files;
}

void
tr_torrentFilesFree( tr_file_stat * files, int fileCount UNUSED )
{
    tr_free( files );
}

/***
****
***/

tr_peer_stat *
tr_torrentPeers( const tr_torrent * tor, int * peerCount )
{
    return tr_peerMgrPeerStats( tor->handle->peerMgr,
                                tor->info.hash, peerCount );
}

void tr_torrentPeersFree( tr_peer_stat * peers, int peerCount UNUSED )
{
    tr_free( peers );
}

void tr_torrentAvailability( const tr_torrent * tor, int8_t * tab, int size )
{
    return tr_peerMgrTorrentAvailability( tor->handle->peerMgr,
                                          tor->info.hash,
                                          tab, size );
}

void tr_torrentAmountFinished( const tr_torrent * tor, float * tab, int size )
{
    int i;
    float interval;
    tr_torrentLock( tor );

    interval = (float)tor->info.pieceCount / (float)size;
    for( i = 0; i < size; i++ )
    {
        int piece = i * interval;
        tab[i] = tr_cpPercentBlocksInPiece( tor->completion, piece );
    }

    tr_torrentUnlock( tor );
}

void
tr_torrentResetTransferStats( tr_torrent * tor )
{
    tr_torrentLock( tor );

    tor->downloadedPrev += tor->downloadedCur;
    tor->downloadedCur   = 0;
    tor->uploadedPrev   += tor->uploadedCur;
    tor->uploadedCur     = 0;
    tor->corruptPrev    += tor->corruptCur;
    tor->corruptCur      = 0;

    tr_torrentUnlock( tor );
}


void
tr_torrentSetHasPiece( tr_torrent * tor, int pieceIndex, int has )
{
    tr_torrentLock( tor );

    if( has )
        tr_cpPieceAdd( tor->completion, pieceIndex );
    else
        tr_cpPieceRem( tor->completion, pieceIndex );

    tr_torrentUnlock( tor );
}

void tr_torrentRemoveSaved( tr_torrent * tor )
{
    tr_metainfoRemoveSaved( tor->info.hashString, tor->handle->tag );
}

void tr_torrentRecheck( tr_torrent * tor )
{
    if( !tor->uncheckedPieces )
        tor->uncheckedPieces = tr_bitfieldNew( tor->info.pieceCount );
    tr_bitfieldAddRange( tor->uncheckedPieces, 0, tor->info.pieceCount );

    tr_ioRecheckAdd( tor, recheckDoneCB, tor->runStatus );
}

/***
****
***/

void
tr_torrentStart( tr_torrent * tor )
{
    tr_ioRecheckAdd( tor, recheckDoneCB, TR_RUN_RUNNING );
}

static void
tr_torrentFree( tr_torrent * tor )
{
    tr_torrent * t;
    tr_handle * h = tor->handle;
    tr_info * inf = &tor->info;

    assert( tor != NULL );
    assert( tor->runStatus == TR_RUN_STOPPED );

    tr_sharedLock( h->shared );

    tr_peerMgrRemoveTorrent( h->peerMgr, tor->info.hash );

    tr_lockFree( tor->lock );
    tr_cpClose( tor->completion );

    tr_rcClose( tor->upload );
    tr_rcClose( tor->download );
    tr_rcClose( tor->swarmspeed );

    tr_trackerUnsubscribe( tor->tracker, tor->trackerSubscription );
    tr_trackerFree( tor->tracker );
    tor->tracker = NULL;

    tr_free( tor->destination );

    if( tor == h->torrentList )
        h->torrentList = tor->next;
    else for( t=h->torrentList; t!=NULL; t=t->next ) {
        if( t->next == tor ) {
            t->next = tor->next;
            break;
        }
    }

    assert( h->torrentCount >= 1 );
    h->torrentCount--;

    tr_inf( "closing torrent %s... %d torrents left",
            tor->info.name, h->torrentCount );

    tr_metainfoFree( inf );
    tr_free( tor );

    tr_sharedUnlock( h->shared );
}

static int
freeWhenStopped( void * vtor )
{
    tr_torrent * tor = vtor;

    if( tor->runStatus != TR_RUN_STOPPED ) /* keep waiting */
        return TRUE;

    tr_torrentFree( tor );
    return FALSE;
}

static void
tr_torrentStopImpl( void * vtor )
{
    tr_torrent * tor = vtor;

    switch( tor->runStatus )
    {
        case TR_RUN_CHECKING_WAIT:
        case TR_RUN_CHECKING:
            tor->doStopAfterHashCheck = 1;
            tr_ioRecheckRemove( tor );
            break;

        case TR_RUN_RUNNING:
            saveFastResumeNow( tor );
            tr_peerMgrStopTorrent( tor->handle->peerMgr, tor->info.hash );
            tor->runStatus = TR_RUN_STOPPING;
            tr_trackerStop( tor->tracker );
            tr_ioClose( tor );
            break;

        case TR_RUN_STOPPING:
        case TR_RUN_STOPPED:
            break;
    }
}

void
tr_torrentStop( tr_torrent * tor )
{
    tr_runInEventThread( tor->handle, tr_torrentStopImpl, tor );
}

void
tr_torrentClose( tr_torrent * tor )
{
    tor->runStatusToSave = tor->runStatus;
    tor->runStatusToSaveIsSet = TRUE;
    tr_torrentStop( tor );
    tr_timerNew( tor->handle, freeWhenStopped, tor, 250 );
}

void
tr_torrentRecheckCompleteness( tr_torrent * tor )
{
    cp_status_t cpStatus;

    tr_torrentLock( tor );

    cpStatus = tr_cpGetStatus( tor->completion );
    if( cpStatus != tor->cpStatus ) {
        tor->cpStatus = cpStatus;
        tor->hasChangedState = tor->cpStatus;  /* tell the client... */
        if( (cpStatus == TR_CP_COMPLETE) /* ...and if we're complete */
            && tor->downloadedCur ) {        /* and it just happened */
            tr_trackerCompleted( tor->tracker ); /* tell the tracker */
        }
        tr_ioClose( tor );
        saveFastResumeSoon( tor );
    }
    tr_torrentUnlock( tor );
}

/**
***  File priorities
**/

void
tr_torrentSetFilePriority( tr_torrent   * tor,
                           int            fileIndex,
                           tr_priority_t  priority )
{
    int i;
    tr_file * file;

    tr_torrentLock( tor );

    assert( tor != NULL );
    assert( 0<=fileIndex && fileIndex<tor->info.fileCount );
    assert( priority==TR_PRI_LOW || priority==TR_PRI_NORMAL || priority==TR_PRI_HIGH );

    file = &tor->info.files[fileIndex];
    file->priority = priority;
    for( i=file->firstPiece; i<=file->lastPiece; ++i )
      tor->info.pieces[i].priority = calculatePiecePriority( tor, i );

    tr_dbg ( "Setting file #%d (pieces %d-%d) priority to %d (%s)",
             fileIndex, file->firstPiece, file->lastPiece,
             priority, tor->info.files[fileIndex].name );

    saveFastResumeSoon( tor );

    tr_torrentUnlock( tor );
}

void
tr_torrentSetFilePriorities( tr_torrent     * tor,
                             int            * files,
                             int              fileCount,
                             tr_priority_t    priority )
{
    int i;
    for( i=0; i<fileCount; ++i )
        tr_torrentSetFilePriority( tor, files[i], priority );
}

tr_priority_t
tr_torrentGetFilePriority( const tr_torrent *  tor, int file )
{
    tr_priority_t ret;

    tr_torrentLock( tor );
    assert( tor != NULL );
    assert( 0<=file && file<tor->info.fileCount );
    ret = tor->info.files[file].priority;
    tr_torrentUnlock( tor );

    return ret;
}


tr_priority_t*
tr_torrentGetFilePriorities( const tr_torrent * tor )
{
    int i;
    tr_priority_t * p;

    tr_torrentLock( tor );
    p = tr_new0( tr_priority_t, tor->info.fileCount );
    for( i=0; i<tor->info.fileCount; ++i )
        p[i] = tor->info.files[i].priority;
    tr_torrentUnlock( tor );

    return p;
}

/**
***  File DND
**/

int
tr_torrentGetFileDL( const tr_torrent * tor,
                     int                file )
{
    int doDownload;
    tr_torrentLock( tor );

    assert( 0<=file && file<tor->info.fileCount );
    doDownload = !tor->info.files[file].dnd;

    tr_torrentUnlock( tor );
    return doDownload != 0;
}

void
tr_torrentSetFileDL( tr_torrent  * tor,
                     int           fileIndex,
                     int           doDownload )
{
    tr_file * file;
    const int dnd = !doDownload;
    int firstPiece, firstPieceDND;
    int lastPiece, lastPieceDND;
    int i;

    tr_torrentLock( tor );

    file = &tor->info.files[fileIndex];
    file->dnd = dnd;
    firstPiece = file->firstPiece;
    lastPiece = file->lastPiece;

    /* can't set the first piece to DND unless
       every file using that piece is DND */
    firstPieceDND = dnd;
    for( i=fileIndex-1; firstPieceDND && i>=0; --i ) {
        if( tor->info.files[i].lastPiece != firstPiece )
            break;
        firstPieceDND = tor->info.files[i].dnd;
    }

    /* can't set the last piece to DND unless
       every file using that piece is DND */
    lastPieceDND = dnd;
    for( i=fileIndex+1; lastPieceDND && i<tor->info.fileCount; ++i ) {
        if( tor->info.files[i].firstPiece != lastPiece )
            break;
        lastPieceDND = tor->info.files[i].dnd;
    }

    if( firstPiece == lastPiece )
    {
        tor->info.pieces[firstPiece].dnd = firstPieceDND && lastPieceDND;
    }
    else
    {
        tor->info.pieces[firstPiece].dnd = firstPieceDND;
        tor->info.pieces[lastPiece].dnd = lastPieceDND;
        for( i=firstPiece+1; i<lastPiece; ++i )
            tor->info.pieces[i].dnd = dnd;
    }

    tr_cpInvalidateDND ( tor->completion );

    saveFastResumeSoon( tor );

    tr_torrentUnlock( tor );
}

void
tr_torrentSetFileDLs ( tr_torrent  * tor,
                       int         * files,
                       int           fileCount,
                       int           doDownload )
{
    int i;
    for( i=0; i<fileCount; ++i )
        tr_torrentSetFileDL( tor, files[i], doDownload );
}

/***
****
***/

int _tr_block( const tr_torrent * tor, int index, int begin )
{
    const tr_info * inf = &tor->info;
    return index * ( inf->pieceSize / tor->blockSize ) +
        begin / tor->blockSize;
}

uint64_t
tr_pieceOffset( const tr_torrent * tor, int index, int begin, int length )
{
    uint64_t ret;
    ret = tor->info.pieceSize;
    ret *= index;
    ret += begin;
    ret += length;
    return ret;
}