From cf2311b09f788447d1c079274405477992eee9e8 Mon Sep 17 00:00:00 2001
From: Bent Bisballe Nyeng <deva@aasimon.org>
Date: Sat, 24 Nov 2018 12:29:25 +0100
Subject: Make midnam threadsafe.

---
 pluginlv2.cc | 22 +++++++++++++++++-----
 pluginlv2.h  |  8 ++++----
 2 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/pluginlv2.cc b/pluginlv2.cc
index 6474d5c..d12c0e7 100644
--- a/pluginlv2.cc
+++ b/pluginlv2.cc
@@ -39,6 +39,15 @@
 #include <lv2/lv2plug.in/ns/ext/midi/midi.h>
 #include <lv2/lv2plug.in/ns/ext/instance-access/instance-access.h>
 
+void PluginLV2::init()
+{
+	for(auto& m : midnamData)
+	{
+		m.first = -1; // Mark midnam slot as unsued.
+		m.second.reserve(64); // Reserve 64 characters for the midnam name.
+	}
+}
+
 bool PluginLV2::getFreeWheel() const
 {
 	return free_wheel;
@@ -363,10 +372,10 @@ void PluginLV2::run(LV2_Handle instance, uint32_t sample_count)
 	plugin_lv2->pos += sample_count;
 
 #ifdef MIDNAM_INTERFACE
-	if(plugin_lv2->midnam && plugin_lv2->midnam_changed)
+	if(plugin_lv2->midnam && plugin_lv2->midnam_changed.load())
 	{
 		plugin_lv2->midnam->update(plugin_lv2->midnam->handle);
-		plugin_lv2->midnam_changed = false;
+		plugin_lv2->midnam_changed.store(false);
 	}
 #endif
 
@@ -490,14 +499,17 @@ void PluginLV2::setMidnamData(const std::vector<std::pair<int, std::string>>& mi
 	auto idx = 0u;
 	for(const auto& m : midnam)
 	{
-		this->midnamData[idx] = m;
+		midnamData[idx].first = m.first;
+		// Duplicate name making sure no reallocation is being performed.
+		midnamData[idx].second =
+			m.second.substr(0, midnamData[idx].second.capacity() - 1);
 		idx++;
 	}
 	for(;idx < this->midnamData.size(); ++idx)
 	{
-		this->midnamData[idx] = {-1, {}};
+		midnamData[idx].first = -1; // Mark as unused
 	}
-	midnam_changed = true;
+	midnam_changed.store(true);
 }
 
 #ifdef MIDNAM_INTERFACE
diff --git a/pluginlv2.h b/pluginlv2.h
index 43563cc..2ff2226 100644
--- a/pluginlv2.h
+++ b/pluginlv2.h
@@ -29,6 +29,7 @@
 #include <plugin.h>
 
 #include <array>
+#include <atomic>
 
 #include <lv2/lv2plug.in/ns/lv2core/lv2.h>
 #include <lv2/lv2plug.in/ns/ext/urid/urid.h>
@@ -62,7 +63,7 @@ public:
 	virtual ~PluginLV2() = default;
 
 	//! Not used in LV2
-	void init() override {}
+	void init() override;
 
 	//! Get current free-wheel mode.
 	bool getFreeWheel() const override;
@@ -271,9 +272,8 @@ private:
 	static char* MidnamModel (LV2_Handle instance);
 	static void  MidnamFree  (char*);
 #endif
-	// TODO:: Make this list thread safe!
-	std::array<std::pair<int, std::string>, 127> midnamData;
-	volatile bool midnam_changed{false};
+	std::atomic<bool> midnam_changed{false};
+	std::array<std::pair<int, std::string>, 127> midnamData; // At most 127 different midinotes.
 
 	bool active{false};
 
-- 
cgit v1.2.3