moved scoped tempo map from GUI to libtemporal

libs/temporal/debug.cc

@@ -27,4 +27,5 @@ PBD::DebugBits PBD::DEBUG::Grid = PBD::new_debug_bit ("Grid");
 PBD::DebugBits PBD::DEBUG::SnapBBT = PBD::new_debug_bit ("SnapBBT");
 PBD::DebugBits PBD::DEBUG::Beats = PBD::new_debug_bit ("Beats");
 PBD::DebugBits PBD::DEBUG::MapReset = PBD::new_debug_bit ("MapReset");
+PBD::DebugBits PBD::DEBUG::ScopedTempoMap = PBD::new_debug_bit ("scopedtempomap");
 

libs/temporal/tempo.cc

@@ -825,6 +825,7 @@ GridIterator::valid_for (TempoMap const & m, superclock_t start, uint32_t bmod,
 /* TEMPOMAP */
 
 TempoMap::TempoMap (Tempo const & initial_tempo, Meter const & initial_meter)
+	: _scope_owner (nullptr)
 {
 	TempoPoint* tp = new TempoPoint (*this, initial_tempo, 0, Beats(), BBT_Time());
 	MeterPoint* mp = new MeterPoint (*this, initial_meter, 0, Beats(), BBT_Time());
@@ -841,15 +842,23 @@ TempoMap::~TempoMap()
 }
 
 TempoMap::TempoMap (XMLNode const & node, int version)
+	: _scope_owner (nullptr)
 {
 	set_state (node, version);
 }
 
 TempoMap::TempoMap (TempoMap const & other)
+	: _scope_owner (nullptr)
 {
 	copy_points (other);
 }
 
+void
+TempoMap::set_scope_owner (ScopedTempoMapOwner& sco)
+{
+	_scope_owner = &sco;
+}
+
 TempoMap&
 TempoMap::operator= (TempoMap const & other)
 {

libs/temporal/temporal/debug.h

@@ -30,6 +30,7 @@ namespace PBD {
 		LIBTEMPORAL_API extern DebugBits SnapBBT;
 		LIBTEMPORAL_API extern DebugBits Beats;
 		LIBTEMPORAL_API extern DebugBits MapReset;
+		LIBTEMPORAL_API extern DebugBits ScopedTempoMap;
 	}
 }
 

libs/temporal/temporal/scope.h

@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2025 Paul Davis <paul@linuxaudiosystems.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#pragma once
+
+#include <cstdint>
+#include <memory>
+
+#include "pbd/compose.h"
+
+#include "temporal/debug.h"
+#include "temporal/tempo.h"
+
+namespace Temporal {
+
+class ScopedTempoMapOwner
+{
+ public:
+	ScopedTempoMapOwner () : local_tempo_map_depth (0) {}
+	virtual ~ScopedTempoMapOwner () {}
+
+	void start_local_tempo_map (std::shared_ptr<Temporal::TempoMap> map) {
+		_local_tempo_map = map;
+		in ();
+		DEBUG_TRACE (PBD::DEBUG::ScopedTempoMap, string_compose ("%1: starting local tempo scope\n", scope_name()));
+	}
+
+	void end_local_tempo_map () {
+		DEBUG_TRACE (PBD::DEBUG::ScopedTempoMap, string_compose ("%1: ending local tempo scope\n", scope_name()));
+		local_tempo_map_depth = 1; /* force exit in out() */
+		out ();
+		_local_tempo_map.reset ();
+	}
+
+	uint64_t depth() const { return local_tempo_map_depth; }
+
+	virtual std::string scope_name() const = 0;
+
+  protected:
+	mutable std::shared_ptr<Temporal::TempoMap> _local_tempo_map;
+	mutable uint64_t local_tempo_map_depth;
+
+  private:
+	friend class TempoMapScope;
+
+	void in () const {
+		if (_local_tempo_map && local_tempo_map_depth++ == 0 ) {
+			DEBUG_TRACE (PBD::DEBUG::ScopedTempoMap, string_compose ("%1: in to local tempo  %2\n", scope_name(), local_tempo_map_depth));
+			Temporal::TempoMap::set (_local_tempo_map);
+		}
+	}
+
+	void out () const {
+		DEBUG_TRACE (PBD::DEBUG::ScopedTempoMap, string_compose ("%1: out with local tempo  %2\n", scope_name(), local_tempo_map_depth));
+		if (local_tempo_map_depth && --local_tempo_map_depth == 0) {
+			DEBUG_TRACE (PBD::DEBUG::ScopedTempoMap, string_compose ("%1: done with local tempo, depth now %2\n", scope_name(), local_tempo_map_depth));
+			Temporal::TempoMap::fetch (); /* get current global map into thread-local pointer */
+		}
+	}
+
+};
+
+
+struct TempoMapScope {
+	TempoMapScope (ScopedTempoMapOwner const & sco)
+		: scope (sco)
+	{
+		scope.in ();
+	}
+
+	~TempoMapScope () {
+		scope.out ();
+	}
+
+	ScopedTempoMapOwner const & scope;
+};
+
+} // namespace 
+
+#define EC_LOCAL_TEMPO_SCOPE Temporal::TempoMapScope __tms (*this);

libs/temporal/temporal/tempo.h

@@ -62,6 +62,7 @@ namespace Temporal {
 class Meter;
 class TempoMap;
 class TempoMapCutBuffer;
+class ScopedTempoMapOwner;
 
 class MapOwned {
  protected:
@@ -1009,11 +1010,15 @@ class /*LIBTEMPORAL_API*/ TempoMap : public PBD::StatefulDestructible
 
 	static void map_assert (bool expr, char const * exprstr, char const * file, int line);
 
+	void set_scope_owner (ScopedTempoMapOwner&);
+	ScopedTempoMapOwner* scope_owner() const { return _scope_owner; }
+	
   private:
 	Tempos       _tempos;
 	Meters       _meters;
 	MusicTimes   _bartimes;
 	Points       _points;
+	ScopedTempoMapOwner* _scope_owner;
 
 	int set_tempos_from_state (XMLNode const &);
 	int set_meters_from_state (XMLNode const &);