Tidy up a bit.

git-svn-id: svn://localhost/ardour2/branches/3.0@12283 d708f5d6-7413-0410-9779-e7cbd77b26cf

1 files changed, 23 insertions, 9 deletions

diff --git a/libs/pbd/pbd/signals.py b/libs/pbd/pbd/signals.py
index da7756c359..fb46f9b0a7 100644
--- a/libs/pbd/pbd/signals.py
+++ b/libs/pbd/pbd/signals.py
@@ -33,7 +33,7 @@ if len(sys.argv) < 2:
 
 f = open(sys.argv[1], 'w')
 
-print >>f,"/** THIS FILE IS AUTOGENERATED by signals.py: CHANGES WILL BE LOST */\n\n"
+print >>f,"/** THIS FILE IS AUTOGENERATED by signals.py: CHANGES WILL BE LOST */\n"
 
 # Produce a comma-separated string from a list of substrings,
 # giving an optional prefix to each substring
@@ -75,6 +75,10 @@ def signal(f, n, v):
         typename = "typename "
 
     if v:
+        print >>f, "/** A signal with %d parameters (specialisation for a void return) */" % n
+    else:
+        print >>f, "/** A signal with %d parameters */" % n
+    if v:
         print >>f,"template <%s>" % comma_separated(An, "typename ")
         print >>f,"class Signal%d<%s> : public SignalBase" % (n, comma_separated(["void"] + An))
     else:
@@ -96,6 +100,7 @@ def signal(f, n, v):
     print >>f,"private:"
 
     print >>f,"""
+	/** The slots that this signal will call on emission */
 	typedef std::map<boost::shared_ptr<Connection>, slot_function_type> Slots;
 	Slots _slots;
 """
@@ -105,11 +110,13 @@ def signal(f, n, v):
     print >>f,"\t~Signal%d () {" % n
 
     print >>f,"\t\tboost::mutex::scoped_lock lm (_mutex);"
+    print >>f,"\t\t/* Tell our connection objects that we are going away, so they don't try to call us */"
     print >>f,"\t\tfor (%sSlots::iterator i = _slots.begin(); i != _slots.end(); ++i) {" % typename
 
     print >>f,"\t\t\ti->first->signal_going_away ();"
     print >>f,"\t\t}"
     print >>f,"\t}"
+    print >>f,""
 
     if n == 0:
         p = ""
@@ -123,7 +130,6 @@ def signal(f, n, v):
     print >>f,"\t}"
 
     print >>f,"""
-
 	/** Arrange for @a slot to be executed whenever this signal is emitted. 
 	    Store the connection that represents this arrangement in @a c.
 
@@ -195,9 +201,9 @@ def signal(f, n, v):
 	}
 
 	/** See notes for the ScopedConnectionList variant of this function. This
-	* differs in that it stores the connection to the signal in a single
-	* ScopedConnection rather than a ScopedConnectionList.
-	*/
+	 *  differs in that it stores the connection to the signal in a single
+	 *  ScopedConnection rather than a ScopedConnectionList.
+	 */
 
 	void connect (ScopedConnection& c, 
 		      PBD::EventLoop::InvalidationRecord* ir, 
@@ -223,15 +229,23 @@ def signal(f, n, v):
     else:
         print >>f,"\ttypename C::result_type operator() (%s)" % comma_separated(Anan)
     print >>f,"\t{"
+    print >>f,"\t\t/* First, take a copy of our list of slots as it is now */"
+    print >>f,""
     print >>f,"\t\tSlots s;"
     print >>f,"\t\t{"
     print >>f,"\t\t\tboost::mutex::scoped_lock lm (_mutex);"
     print >>f,"\t\t\ts = _slots;"
     print >>f,"\t\t}"
+    print >>f,""
     if not v:
         print >>f,"\t\tstd::list<R> r;"
-    print >>f,"for (%sSlots::iterator i = s.begin(); i != s.end(); ++i) {" % typename
+    print >>f,"\t\tfor (%sSlots::iterator i = s.begin(); i != s.end(); ++i) {" % typename
     print >>f,"""
+			/* We may have just called a slot, and this may have resulted in
+			   disconnection of other slots from us.  The list copy means that
+			   this won't cause any problems with invalidated iterators, but we
+			   must check to see if the slot we are about to call is still on the list.
+			*/
 			bool still_there = false;
 			{
 				boost::mutex::scoped_lock lm (_mutex);
@@ -245,7 +259,9 @@ def signal(f, n, v):
         print >>f,"\t\t\t\tr.push_back ((i->second)(%s));" % comma_separated(an)
     print >>f,"\t\t\t}"
     print >>f,"\t\t}"
+    print >>f,""
     if not v:
+        print >>f,"\t\t/* Call our combiner to do whatever is required to the result values */"
         print >>f,"\t\tC c;"
         print >>f,"\t\treturn c (r.begin(), r.end());"
     print >>f,"\t}"
@@ -262,7 +278,6 @@ def signal(f, n, v):
     else:
         tp = comma_separated(["R"] + An + ["C"])
 
-    print >>f,""
     print >>f,"private:"
     print >>f,""
     print >>f,"\tfriend class Connection;"
@@ -274,8 +289,7 @@ def signal(f, n, v):
 		boost::mutex::scoped_lock lm (_mutex);
 		_slots[c] = f;
 		return c;
-	}
-"""
+	}"""
 
     print >>f,"""
 	void disconnect (boost::shared_ptr<Connection> c)