From: Paul Davis <paul@linuxaudiosystems.com>
Date: Wed, 9 Jul 2014 14:18:28 +0000 (-0400)
Subject: add mutex to prevent concurrent session state saves.
X-Git-Tag: 4.0-rc1~1601^2~576
X-Git-Url: https://main.carlh.net/gitweb/?a=commitdiff_plain;h=1fd4d40dbbb426d32701f42809f4b33a5659aac4;p=ardour.git

add mutex to prevent concurrent session state saves.

Why wasn't this done 10 years ago?
---

diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index 53215af2b6..595560a119 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -1126,6 +1126,7 @@ class LIBARDOUR_API Session : public PBD::StatefulDestructible, public PBD::Scop
 	friend class    StateProtector;
 	gint            _suspend_save; /* atomic */
 	volatile bool   _save_queued;
+	Glib::Threads::Mutex save_state_lock;
 
 	int      load_options (const XMLNode&);
 	int      load_state (std::string snapshot_name);
diff --git a/libs/ardour/session_state.cc b/libs/ardour/session_state.cc
index 4e99c663f0..42344ea7fd 100644
--- a/libs/ardour/session_state.cc
+++ b/libs/ardour/session_state.cc
@@ -665,6 +665,10 @@ Session::save_state (string snapshot_name, bool pending, bool switch_to_snapshot
 	XMLTree tree;
 	std::string xml_path(_session_dir->root_path());
 
+	/* prevent concurrent saves from different threads */
+
+	Glib::Threads::Mutex::Lock lm (save_state_lock);
+
 	if (!_writable || (_state_of_the_state & CannotSave)) {
 		return 1;
 	}