1 files changed, 143 insertions, 70 deletions

diff --git a/trackerlogic.c b/trackerlogic.c
index c8576f6..d2d279e 100644
--- a/trackerlogic.c
+++ b/trackerlogic.c
@@ -25,6 +25,10 @@
 
 /* GLOBAL VARIABLES */
 static ot_vector all_torrents[256];
+static ot_vector changeset;
+size_t changeset_size = 0;
+time_t last_clean_time = 0;
+
 #ifdef WANT_CLOSED_TRACKER
 int g_closedtracker = 1;
 static ot_torrent* const OT_TORRENT_NOT_ON_WHITELIST = (ot_torrent*)1;
@@ -158,33 +162,6 @@ static int vector_remove_torrent( ot_vector *vector, ot_hash *hash ) {
   return 1;
 }
 
-/* This function deallocates all timedouted pools and shifts all other pools
-   it Returns 1 if torrent itself has not seen an announce for more than OT_TORRENT_TIMEOUT time units
-              0 if torrent is not yet timed out
-   Note: We expect NOW as a parameter since calling time() may be expensive
-*/
-static int clean_peerlist( time_t time_now, ot_peerlist *peer_list ) {
-  int i, timedout = (int)( time_now - peer_list->base );
-
-  if( !timedout ) return 0;
-  if( timedout > OT_POOLS_COUNT ) timedout = OT_POOLS_COUNT;
-
-  for( i = OT_POOLS_COUNT - timedout; i < OT_POOLS_COUNT; ++i )
-    free( peer_list->peers[i].data);
-
-  memmove( peer_list->peers + timedout, peer_list->peers, sizeof( ot_vector ) * (OT_POOLS_COUNT-timedout) );
-  byte_zero( peer_list->peers, sizeof( ot_vector ) * timedout );
-
-  memmove( peer_list->seed_count + timedout, peer_list->seed_count, sizeof( size_t ) * ( OT_POOLS_COUNT - timedout) );
-  byte_zero( peer_list->seed_count, sizeof( size_t ) * timedout );
-
-  if( timedout == OT_POOLS_COUNT )
-    return time_now - peer_list->base > OT_TORRENT_TIMEOUT;
-
-  peer_list->base = time_now;
-  return 0;
-}
-
 ot_torrent *add_peer_to_torrent( ot_hash *hash, ot_peer *peer ) {
   int          exactmatch;
   ot_torrent *torrent;
@@ -219,8 +196,7 @@ ot_torrent *add_peer_to_torrent( ot_hash *hash, ot_peer *peer ) {
 
     byte_zero( torrent->peer_list, sizeof( ot_peerlist ) );
     torrent->peer_list->base = NOW;
-  } else
-    clean_peerlist( NOW, torrent->peer_list );
+  }
 
   /* Sanitize flags: Whoever claims to have completed download, must be a seeder */
   if( ( OT_FLAG( peer ) & ( PEER_FLAG_COMPLETED | PEER_FLAG_SEEDING ) ) == PEER_FLAG_COMPLETED )
@@ -294,7 +270,9 @@ size_t return_peers_for_torrent( ot_torrent *torrent, size_t amount, char *reply
     peer_count += torrent->peer_list->peers[index].size;
     seed_count += torrent->peer_list->seed_count[index];
   }
-  if( peer_count < amount ) amount = peer_count;
+
+  if( peer_count < amount )
+    amount = peer_count;
 
   if( is_tcp )
     r += sprintf( r, "d8:completei%zde10:incompletei%zde8:intervali%ie5:peers%zd:", seed_count, peer_count-seed_count, OT_CLIENT_REQUEST_INTERVAL_RANDOM, 6*amount );
@@ -348,10 +326,8 @@ size_t return_fullscrape_for_tracker( char **reply ) {
   int    i, k;
   char  *r;
 
-  for( i=0; i<256; ++i ) {
-    ot_vector *torrents_list = &all_torrents[i];
-    torrent_count += torrents_list->size;
-  }
+  for( i=0; i<256; ++i )
+    torrent_count += all_torrents[i].size;
 
   if( !( r = *reply = malloc( 128*torrent_count ) ) ) return 0;
 
@@ -380,7 +356,6 @@ size_t return_memstat_for_tracker( char **reply ) {
   size_t torrent_count = 0, j;
   int    i, k;
   char  *r;
-  time_t time_now = NOW;
 
   for( i=0; i<256; ++i ) {
     ot_vector *torrents_list = &all_torrents[i];
@@ -398,7 +373,6 @@ size_t return_memstat_for_tracker( char **reply ) {
       ot_peerlist *peer_list = ( ((ot_torrent*)(torrents_list->data))[j] ).peer_list;
       ot_hash     *hash      =&( ((ot_torrent*)(torrents_list->data))[j] ).hash;
       r += sprintf( r, "\n%s:\n", to_hex( (ot_byte*)hash ) );
-      clean_peerlist( time_now, peer_list );
       for( k=0; k<OT_POOLS_COUNT; ++k )
         r += sprintf( r, "\t%04X %04X\n", ((unsigned int)peer_list->peers[k].size), (unsigned int)peer_list->peers[k].space );
     }
@@ -418,7 +392,6 @@ size_t return_udp_scrape_for_torrent( ot_hash *hash, char *reply ) {
     memset( reply, 0, 12);
   } else {
     unsigned long *r = (unsigned long*) reply;
-    clean_peerlist( NOW, torrent->peer_list );
 
     for( i=0; i<OT_POOLS_COUNT; ++i ) {
       peers += torrent->peer_list->peers[i].size;
@@ -440,7 +413,6 @@ size_t return_tcp_scrape_for_torrent( ot_hash *hash, char *reply ) {
   ot_torrent  *torrent = binary_search( hash, torrents_list->data, torrents_list->size, sizeof( ot_torrent ), OT_HASH_COMPARE_SIZE, &exactmatch );
 
   if( !exactmatch ) return sprintf( r, "d5:filesdee" );
-  clean_peerlist( NOW, torrent->peer_list );
 
   for( i=0; i<OT_POOLS_COUNT; ++i ) {
     peers += torrent->peer_list->peers[i].size;
@@ -453,36 +425,145 @@ size_t return_tcp_scrape_for_torrent( ot_hash *hash, char *reply ) {
   return r - reply;
 }
 
-size_t return_sync_for_torrent( ot_hash *hash, char **reply ) {
-  int         exactmatch;
-  size_t      peers = 0;
-  char       *r;
-  ot_vector  *torrents_list = &all_torrents[*hash[0]];
-  ot_torrent *torrent = binary_search( hash, torrents_list->data, torrents_list->size, sizeof( ot_torrent ), OT_HASH_COMPARE_SIZE, &exactmatch );
+/* Throw away old changeset */
+static void release_changeset( void ) {
+  ot_byte **changeset_ptrs = (ot_byte**)(changeset.data);
+  int i;
+
+  for( i = 0; i < changeset.size; ++i )
+    free( changeset_ptrs[i] );
+
+  free( changeset_ptrs );
+  byte_zero( &changeset, sizeof( changeset ) );
+
+  changeset_size = 0;
+}
+
+static void add_pool_to_changeset( ot_hash *hash, ot_peer *peers, size_t peer_count ) {
+  ot_byte *pool_copy = (ot_byte *)malloc( sizeof( size_t ) + sizeof( ot_hash ) + sizeof( ot_peer ) * peer_count + 13 );
+  size_t r = 0;
+
+  if( !pool_copy )
+    return;
+
+  memmove( pool_copy + sizeof( size_t ), "20:", 3 );
+  memmove( pool_copy + sizeof( size_t ) + 3, hash, sizeof( ot_hash ) );
+  r = sizeof( size_t ) + 3 + sizeof( ot_hash );
+  r += sprintf( (char*)pool_copy + r, "%zd:", sizeof( ot_peer ) * peer_count );
+  memmove( pool_copy + r, peers, sizeof( ot_peer ) * peer_count );
+  r += sizeof( ot_peer ) * peer_count;
+
+  /* Without the length field */
+  *(size_t*)pool_copy = r - sizeof( size_t );
+
+  if( changeset.size + 1 >= changeset.space ) {
+    size_t   new_space = changeset.space ? OT_VECTOR_GROW_RATIO * changeset.space : OT_VECTOR_MIN_MEMBERS;
+    ot_byte *new_data = realloc( changeset.data, new_space * sizeof( ot_byte *) );
+
+    if( !new_data )
+      return free( pool_copy );
+
+    changeset.data = new_data;
+    changeset.space = new_space;
+  }
+
+  ((ot_byte**)changeset.data)[changeset.size++] = pool_copy;
+
+  /* Without the length field */
+  changeset_size += r - sizeof( size_t );
+}
+
+/* Proposed output format
+   d4:syncd20:<info_hash>8*N:(xxxxyy)*Nee
+*/
+size_t return_changeset_for_tracker( char **reply ) {
+  size_t i, r = 8;
+
+  clean_all_torrents();
+
+  *reply = malloc( 8 + changeset_size + 2 );
+  if( !*reply )
+    return 0;
 
-  if( exactmatch ) {
-    clean_peerlist( NOW, torrent->peer_list );
-    peers = torrent->peer_list->peers[0].size;
+  memmove( *reply, "d4:syncd", 8 );
+  for( i = 0; i < changeset.size; ++i ) {
+    ot_byte *data = ((ot_byte**)changeset.data)[i];
+    memmove( *reply + r, data + sizeof( size_t ), *(size_t*)data );
+    r += *(size_t*)data;
   }
 
-  if( !( r = *reply = malloc( 10 + peers * sizeof( ot_peer ) ) ) ) return 0;
+  (*reply)[r++] = 'e';
+  (*reply)[r++] = 'e';
+
+  return r;
+}
+
+/* Clean up all torrents, remove timedout pools and
+   torrents, also prepare new changeset */
+void clean_all_torrents( void ) {
+  int    i, j, k;
+  time_t time_now = NOW;
+  size_t peers_count;
+
+  if( time_now <= last_clean_time )
+    return;
+  last_clean_time = time_now;
+
+  release_changeset();
 
-  memmove( r, "d4:sync", 7 );
-  r += 7;
-  r += sprintf( r, "%zd:", peers * sizeof( ot_peer ) );
-  if( peers ) {
-    memmove( r, torrent->peer_list->peers[0].data, peers * sizeof( ot_peer ) );
-    r += peers * sizeof( ot_peer );
+  for( i=0; i<256; ++i ) {
+    ot_vector *torrents_list = &all_torrents[i];
+    for( j=0; j<torrents_list->size; ++j ) {
+      ot_peerlist *peer_list = ( ((ot_torrent*)(torrents_list->data))[j] ).peer_list;
+      ot_hash     *hash =&( ((ot_torrent*)(torrents_list->data))[j] ).hash;
+
+      time_t timedout = (int)( time_now - peer_list->base );
+
+      /* Torrent has idled out */
+      if( timedout > OT_TORRENT_TIMEOUT ) {
+        vector_remove_torrent( torrents_list, hash );
+        --j;
+      }
+
+      /* If nothing to be cleaned here, handle next torrent */
+      if( timedout > OT_POOLS_COUNT )
+        continue;
+
+      /* Release vectors that have timed out */
+      for( k = OT_POOLS_COUNT - timedout; k < OT_POOLS_COUNT; ++k )
+        free( peer_list->peers[k].data);
+
+      /* Shift vectors back by the amount of pools that were shifted out */
+      memmove( peer_list->peers + timedout, peer_list->peers, sizeof( ot_vector ) * ( OT_POOLS_COUNT - timedout ) );
+      byte_zero( peer_list->peers, sizeof( ot_vector ) * timedout );
+
+      /* Shift back seed counts as well */
+      memmove( peer_list->seed_count + timedout, peer_list->seed_count, sizeof( size_t ) * ( OT_POOLS_COUNT - timedout ) );
+      byte_zero( peer_list->seed_count, sizeof( size_t ) * timedout );
+
+      /* Save the block modified within last OT_POOLS_TIMEOUT */
+      if( peer_list->peers[1].size )
+        add_pool_to_changeset( hash, peer_list->peers[1].data, peer_list->peers[1].size );
+
+      peers_count = 0;
+      for( k = 0; k < OT_POOLS_COUNT; ++k )
+        peers_count += peer_list->peers[k].size;
+
+      if( peers_count ) {
+        peer_list->base = time_now;
+      } else {
+        /* When we got here, the last time that torrent
+           has been touched is OT_POOLS_COUNT units before */
+        peer_list->base = time_now - OT_POOLS_COUNT;
+      }
+    }
   }
-  *r++ = 'e';
-  return r - *reply;
 }
 
 typedef struct { int val; ot_torrent * torrent; } ot_record;
 
 /* Fetches stats from tracker */
 size_t return_stats_for_tracker( char *reply, int mode ) {
-  time_t    time_now = NOW;
   size_t    torrent_count = 0, peer_count = 0, seed_count = 0, j;
   ot_record top5s[5], top5c[5];
   char     *r  = reply;
@@ -498,12 +579,6 @@ size_t return_stats_for_tracker( char *reply, int mode ) {
       ot_peerlist *peer_list = ( ((ot_torrent*)(torrents_list->data))[j] ).peer_list;
       size_t local_peers = 0, local_seeds = 0;
 
-      if( clean_peerlist( time_now, peer_list ) ) {
-        ot_hash *hash =&( ((ot_torrent*)(torrents_list->data))[j] ).hash;
-        vector_remove_torrent( torrents_list, hash );
-        --j;
-        continue;
-      }
       for( k=0; k<OT_POOLS_COUNT; ++k ) {
         local_peers += peer_list->peers[k].size;
         local_seeds += peer_list->seed_count[k];
@@ -549,12 +624,6 @@ void remove_peer_from_torrent( ot_hash *hash, ot_peer *peer ) {
 
   if( !exactmatch ) return;
 
-  /* Maybe this does the job */
-  if( clean_peerlist( NOW, torrent->peer_list ) ) {
-    vector_remove_torrent( torrents_list, hash );
-    return;
-  }
-
   for( i=0; i<OT_POOLS_COUNT; ++i )
     switch( vector_remove_peer( &torrent->peer_list->peers[i], peer, i == 0 ) ) {
       case 0: continue;
@@ -572,7 +641,9 @@ int init_logic( const char * const serverdir ) {
   srandom( time(NULL) );
 
   /* Initialize control structures */
-  byte_zero( all_torrents, sizeof (all_torrents) );
+  byte_zero( all_torrents, sizeof( all_torrents ) );
+  byte_zero( &changeset, sizeof( changeset ) );
+  changeset_size = 0;
 
   return 0;
 }
@@ -591,4 +662,6 @@ void deinit_logic( void ) {
     }
   }
   byte_zero( all_torrents, sizeof (all_torrents));
+  byte_zero( &changeset, sizeof( changeset ) );
+  changeset_size = 0;
 }