Resolve Coverity issue with Parser::Transition's ownership of Action *.

This commit is somewhat subtle; it informs Coverity that
Parser::Transition only holds an Action* temporarily, and should never
create/delete one.  I believe runtime checkers should also understand
this OK.

Signed-off-by: John Hood <cgull@glup.org>

src/terminal/parser.cc

@@ -63,6 +63,7 @@ std::list<Parser::Action *> Parser::Parser::input( wchar_t ch )
   }
 
   append_or_delete( tx.action, ret );
+  tx.action = NULL;
 
   if ( tx.next_state != NULL ) {
     append_or_delete( tx.next_state->enter(), ret );

src/terminal/parserstate.cc

@@ -56,7 +56,7 @@ Transition State::anywhere_rule( wchar_t ch ) const
     return Transition( &family->s_CSI_Entry );
   }
 
-  return Transition( NULL, NULL ); /* don't allocate an Ignore action */
+  return Transition(( State * )NULL, NULL ); /* don't allocate an Ignore action */
 }
 
 Transition State::input( wchar_t ch ) const

src/terminal/parsertransition.h

@@ -43,6 +43,8 @@ namespace Parser {
   class Transition
   {
   public:
+    // Transition is only a courier for an Action; it should
+    // never create/delete one on its own.
     Action *action;
     State *next_state;
 
@@ -56,14 +58,21 @@ namespace Parser {
 
       return *this;
     }
-    virtual ~Transition() {}
+    virtual ~Transition()
+    {
+      // Indicate to checkers that we don't own *action anymore
+      action = NULL;
+    }
 
     Transition( Action *s_action=new Ignore, State *s_next_state=NULL )
       : action( s_action ), next_state( s_next_state )
     {}
 
-    Transition( State *s_next_state )
-      : action( new Ignore ), next_state( s_next_state )
+    // This is only ever used in the 1-argument form;
+    // we use this instead of an initializer to
+    // tell Coverity the object never owns *action.
+    Transition( State *s_next_state, Action *s_action=new Ignore )
+      : action( s_action ), next_state( s_next_state )
     {}
   };
 }