deprecate and remove guided read cache (#904)

include/libtorrent/peer_connection.hpp

@@ -788,7 +788,6 @@ namespace libtorrent
 		peer_connection& operator=(peer_connection const&);
 
 		void do_update_interest();
-		int preferred_caching() const;
 		void fill_send_buffer();
 		void on_disk_read_complete(disk_io_job const* j, peer_request r
 			, time_point issue_time);

include/libtorrent/settings_pack.hpp

@@ -382,12 +382,16 @@ namespace libtorrent
 			// place.
 			volatile_read_cache,
 
+#ifndef TORRENT_NO_DEPRECATE
 			// ``guided_read_cache`` enables the disk cache to adjust the size of
 			// a cache line generated by peers to depend on the upload rate you
 			// are sending to that peer. The intention is to optimize the RAM
 			// usage of the cache, to read ahead further for peers that you're
 			// sending faster to.
 			guided_read_cache,
+#else
+			deprecated13,
+#endif
 
 			// ``no_atime_storage`` this is a linux-only option and passes in the
 			// ``O_NOATIME`` to ``open()`` when opening files. This may lead to
@@ -1165,6 +1169,7 @@ namespace libtorrent
 			// to match the expiration time for tokens.
 			udp_tracker_token_expiry,
 
+#ifndef TORRENT_NO_DEPRECATE
 			// ``default_cache_min_age`` is the minimum number of seconds any read
 			// cache line is kept in the cache. This defaults to one second but
 			// may be greater if ``guided_read_cache`` is enabled. Having a lower
@@ -1172,6 +1177,9 @@ namespace libtorrent
 			// to avoid swapping the same pieces in and out of the cache in case
 			// there is a shortage of spare cache space.
 			default_cache_min_age,
+#else
+			deprecated16,
+#endif
 
 			// ``num_optimistic_unchoke_slots`` is the number of optimistic
 			// unchoke slots to use. It defaults to 0, which means automatic.

src/peer_connection.cpp

@@ -5026,31 +5026,6 @@ namespace libtorrent
 		send_block_requests();
 	}
 
-	int peer_connection::preferred_caching() const
-	{
-		TORRENT_ASSERT(is_single_thread());
-		int line_size = 0;
-		if (m_settings.get_bool(settings_pack::guided_read_cache))
-		{
-			boost::shared_ptr<torrent> t = m_torrent.lock();
-			int upload_rate = m_statistics.upload_payload_rate();
-			if (upload_rate == 0) upload_rate = 1;
-
-			int num_uploads = m_ses.num_uploads();
-			if (num_uploads == 0) num_uploads = 1;
-
-			// assume half of the cache is write cache if we're downloading
-			// this torrent as well
-			int cache_size = m_settings.get_int(settings_pack::cache_size) / num_uploads;
-			if (!t->is_upload_only()) cache_size /= 2;
-			// cache_size is the amount of cache we have per peer. The
-			// cache line should not be greater than this
-
-			line_size = cache_size;
-		}
-		return line_size;
-	}
-
 	void peer_connection::fill_send_buffer()
 	{
 		TORRENT_ASSERT(is_single_thread());

src/settings_pack.cpp

@@ -172,7 +172,7 @@ namespace libtorrent
 		SET(allow_i2p_mixed, false, nullptr),
 		SET(low_prio_disk, true, nullptr),
 		SET(volatile_read_cache, false, nullptr),
-		SET(guided_read_cache, false, nullptr),
+		DEPRECATED_SET(guided_read_cache, false, nullptr),
 		SET(no_atime_storage, true, nullptr),
 		SET(incoming_starts_queued_torrents, false, nullptr),
 		SET(report_true_downloaded, false, nullptr),
@@ -288,7 +288,7 @@ namespace libtorrent
 		SET(local_service_announce_interval, 5 * 60, nullptr),
 		SET(dht_announce_interval, 15 * 60, &session_impl::update_dht_announce_interval),
 		SET(udp_tracker_token_expiry, 60, nullptr),
-		SET(default_cache_min_age, 1, nullptr),
+		DEPRECATED_SET(default_cache_min_age, 1, nullptr),
 		SET(num_optimistic_unchoke_slots, 0, nullptr),
 		SET(default_est_reciprocation_rate, 16000, nullptr),
 		SET(increase_est_reciprocation_rate, 20, nullptr),