deprecate direct access to array in session_stats_alert (#2033)

bindings/python/src/alert.cpp

@@ -123,11 +123,11 @@ dict session_stats_values(session_stats_alert const& alert)
 {
     std::vector<stats_metric> map = session_stats_metrics();
     dict d;
+    auto counters = alert.counters();
 
-    for (std::vector<stats_metric>::const_iterator i = map.begin();
-       i != map.end(); ++i)
+    for (stats_metric const& m : map)
     {
-        d[i->name] = alert.values[i->value_index];
+        d[m.name] = counters[m.value_index];
     }
     return d;
 }

examples/client_test.cpp

@@ -764,7 +764,7 @@ bool handle_alert(torrent_view& view, session_view& ses_view
 
 	if (session_stats_alert* s = alert_cast<session_stats_alert>(a))
 	{
-		ses_view.update_counters(s->values.data(), int(s->values.size())
+		ses_view.update_counters(s->counters()
 			, duration_cast<microseconds>(s->timestamp().time_since_epoch()).count());
 		return true;
 	}

examples/session_view.cpp

@@ -37,6 +37,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #include <algorithm> // for std::max
 
+using libtorrent::span;
+
 session_view::session_view()
 	: m_position(0)
 	, m_print_utp_stats(false)
@@ -190,8 +192,8 @@ void session_view::render()
 	}
 }
 
-void session_view::update_counters(std::int64_t const* stats_counters
-	, int num_cnt, std::uint64_t t)
+void session_view::update_counters(span<std::int64_t const> stats_counters
+	, std::uint64_t const t)
 {
 	// only update the previous counters if there's been enough
 	// time since it was last updated
@@ -201,7 +203,7 @@ void session_view::update_counters(std::int64_t const* stats_counters
 		m_timestamp[1] = m_timestamp[0];
 	}
 
-	m_cnt[0].assign(stats_counters, stats_counters + num_cnt);
+	m_cnt[0].assign(stats_counters.begin(), stats_counters.end());
 	m_timestamp[0] = t;
 	render();
 }

examples/session_view.hpp

@@ -37,6 +37,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <vector>
 
 #include "libtorrent/session_stats.hpp"
+#include "libtorrent/span.hpp"
 
 struct session_view
 {
@@ -53,8 +54,7 @@ struct session_view
 	void print_utp_stats(bool p) { m_print_utp_stats = p; }
 	bool print_utp_stats() const { return m_print_utp_stats; }
 
-	void update_counters(std::int64_t const* stats_counters, int num_cnt
-		, std::uint64_t t);
+	void update_counters(lt::span<std::int64_t const> stats_counters, std::uint64_t t);
 
 private:
 

include/libtorrent/alert_types.hpp

@@ -1888,7 +1888,19 @@ namespace libtorrent {
 	struct TORRENT_EXPORT session_stats_alert final : alert
 	{
 		session_stats_alert(aux::stack_allocator& alloc, counters const& cnt);
+
+#ifndef TORRENT_NO_DEPRECATE
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+#endif
+#endif
 		TORRENT_DEFINE_ALERT_PRIO(session_stats_alert, 70)
+#ifndef TORRENT_NO_DEPRECATE
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
+#endif
 
 		static const int static_category = alert::stats_notification;
 		virtual std::string message() const override;
@@ -1902,7 +1914,15 @@ namespace libtorrent {
 		// interpret these values throughout the process' runtime.
 		//
 		// For more information, see the session-statistics_ section.
+		span<std::int64_t const> counters() const;
+
+#ifdef TORRENT_NO_DEPRECATE
+	private:
+		// TODO: allocate this on the alert_stack in the future
 		std::array<std::int64_t, counters::num_counters> const values;
+#else
+		std::array<std::int64_t, counters::num_counters> const TORRENT_DEPRECATED_MEMBER values;
+#endif
 	};
 
 #ifndef TORRENT_NO_DEPRECATE

src/alert.cpp

@@ -1740,7 +1740,7 @@ namespace {
 		}
 	}
 
-	session_stats_alert::session_stats_alert(aux::stack_allocator&, counters const& cnt)
+	session_stats_alert::session_stats_alert(aux::stack_allocator&, struct counters const& cnt)
 		: values(counters_to_array(cnt))
 	{}
 
@@ -1759,6 +1759,11 @@ namespace {
 		return ret;
 	}
 
+	span<std::int64_t const> session_stats_alert::counters() const
+	{
+		return values;
+	}
+
 	dht_stats_alert::dht_stats_alert(aux::stack_allocator&
 		, std::vector<dht_routing_bucket> table
 		, std::vector<dht_lookup> requests)

test/setup_transfer.cpp

@@ -150,7 +150,7 @@ std::map<std::string, std::int64_t> get_counters(lt::session& s)
 
 	static std::vector<stats_metric> metrics = session_stats_metrics();
 	for (auto const& m : metrics)
-		ret[m.name] = sa->values[static_cast<std::size_t>(m.value_index)];
+		ret[m.name] = sa->counters()[static_cast<std::size_t>(m.value_index)];
 	return ret;
 }
 namespace {