priority endgame patch

Index: libtransmission/peer-mgr.c===================================================================--- libtransmission/peer-mgr.c	(revision 4337)+++ libtransmission/peer-mgr.c	(working copy)@@ -702,46 +702,84 @@ {     uint32_t i;     uint32_t pieceCount;+    uint32_t blockCount;+    uint32_t unreqCount[3], reqCount[3];     uint32_t * pieces;-    uint64_t *req, *unreq, *ret, *walk;-    int reqCount, unreqCount;+    uint64_t * ret, * walk;+    uint64_t * unreq[3], *req[3];     const tr_torrent * tor = t->tor;      assert( torrentIsLocked( t ) );      pieces = getPreferredPieces( t, &pieceCount ); -    req = tr_new( uint64_t, pieceCount *  tor->blockCountInPiece );-    reqCount = 0;-    unreq = tr_new( uint64_t, pieceCount *  tor->blockCountInPiece );-    unreqCount = 0;+    /**+     * Now we walk through those preferred pieces to find all the blocks+     * are still missing from them.  We put unrequested blocks first,+     * of course, but by including requested blocks afterwards then endgame+     * handling happens naturally.+     *+     * By doing this once per priority we also effectively get an endgame mode+     * for each priority.  The helps keep high priority files from getting+     * stuck at 99% due of unresponsive peers.+     */ -    for( i=0; i<pieceCount; ++i ) {+    /* make temporary bins for the four tiers of blocks */+    for( i=0; i<3; ++i ) {+        req[i] = tr_new( uint64_t, pieceCount *  tor->blockCountInPiece );+        reqCount[i] = 0;+        unreq[i] = tr_new( uint64_t, pieceCount *  tor->blockCountInPiece );+        unreqCount[i] = 0;+    }++    /* sort the blocks into our temp bins */+    for( i=blockCount=0; i<pieceCount; ++i )+    {         const uint32_t index = pieces[i];+        const int priorityIndex = tor->info.pieces[index].priority + 1;         const int begin = tr_torPieceFirstBlock( tor, index );         const int end = begin + tr_torPieceCountBlocks( tor, (int)index );         int block;+         for( block=begin; block<end; ++block )+        {             if( tr_cpBlockIsComplete( tor->completion, block ) )                 continue;-            else if( tr_bitfieldHas( t->requested, block ) )-                req[reqCount++] = block;++            ++blockCount;++            if( tr_bitfieldHas( t->requested, block ) )+            {+                const uint32_t n = reqCount[priorityIndex]++;+                req[priorityIndex][n] = block;+            }             else-                unreq[unreqCount++] = block;+            {+                const uint32_t n = unreqCount[priorityIndex]++;+                unreq[priorityIndex][n] = block;+            }+        }     } -    ret = walk = tr_new( uint64_t, unreqCount + reqCount );-    memcpy( walk, unreq, sizeof(uint64_t) * unreqCount );-    walk += unreqCount;-    memcpy( walk, req, sizeof(uint64_t) * reqCount );-    walk += reqCount;-    assert( ( walk - ret ) == ( unreqCount + reqCount ) );-    *setmeCount = walk - ret;+    /* join the bins together.  blocks will then be in order of+     * those we want to request first, to those we want to request last */ -    tr_free( req );-    tr_free( unreq );+    ret = walk = tr_new( uint64_t, blockCount );+    for( i=0; i<3; ++i ) {+        memcpy( walk, unreq[i], sizeof(uint64_t) * unreqCount[i] );+        walk += unreqCount[i];+        memcpy( walk, req[i], sizeof(uint64_t) * reqCount[i] );+        walk += reqCount[i];+    }+    assert( ( walk - ret ) == blockCount );+    *setmeCount = blockCount;++    /* cleanup */     tr_free( pieces );-+    for( i=0; i<3; ++i ) {+        tr_free( unreq[i] );+        tr_free( req[i] );+    }     return ret; }