Initial import of the CDE 2.1.30 sources from the Open Group.

cde/programs/dtinfo/DtMmdb/dti_excs/Jump_Environment.C

@@ -0,0 +1,156 @@
+// $XConsortium: Jump_Environment.C /main/6 1996/10/04 09:37:00 drk $
+#ifndef NATIVE_EXCEPTIONS
+#include "Exceptions.hh"
+
+Jump_Environment *Jump_Environment::g_jump_env_stack;
+
+#ifdef EXC_DEBUG
+int Jump_Environment::g_level;
+#endif
+
+unsigned short Unwind_Stack::g_top ;
+
+#ifdef C_API
+Unwind_Record* Unwind_Stack::g_stack = 0; // inited in init.C
+#else
+Unwind_Record Unwind_Stack::g_stack[UNWIND_STACK_SIZE];
+#endif
+
+
+// /////////////////////////////////////////////////////////////////
+// Jump_Environment - class constructor
+// /////////////////////////////////////////////////////////////////
+
+Jump_Environment::Jump_Environment()
+: f_unwinding (0), f_active_exception (NULL)
+{
+  PRINTF (("<%d> New Jump_Environment @ %p\n", ++g_level, this));
+  // Push this on to the top of the jump env stack. 
+  f_next = g_jump_env_stack;
+  g_jump_env_stack = this;
+}
+
+// /////////////////////////////////////////////////////////////////
+// class destructor
+// /////////////////////////////////////////////////////////////////
+
+Jump_Environment::~Jump_Environment()
+{
+  // If g_jump_env_stack == this an exception wasn't thrown.
+  // (Because at throw time we set g_jump_env_stack to f_next.) 
+  if (g_jump_env_stack == this)
+    {
+      g_jump_env_stack = f_next;
+    }
+  // An exception was thrown in our try block.
+  // An exception may have been thrown in our catch block.
+  // If one was, g_jump_env_stack->f_active_exception != NULL. 
+  if (f_active_exception != NULL)
+    {
+      delete_active();
+    }
+  PRINTF (("<%d> Done with Jump_Environment @ %p\n",
+	   g_level--, this));
+}
+
+
+// /////////////////////////////////////////////////////////////////
+// unwind - call destructors for stack based objects
+// /////////////////////////////////////////////////////////////////
+
+void
+Jump_Environment::do_unwind_and_jump (Exception *exception, int debugging)
+{
+  PRINTF (("----- <%d> Unwinding stack -----\n", g_level));
+
+  // Remember the current exception so we can delete it later.
+  f_active_exception = exception;
+
+  // Check for a throw out of a destructor. 
+  if (f_unwinding)
+    {
+      Exceptions::error (Exceptions::f_msg_throw_from_destructor,
+			 Exceptions::APPLICATION_ERROR);
+      terminate();
+    }
+
+  f_unwinding = 1;
+
+  // Call the destructor of each objet on the stack in reverse.
+  // Length is automatically decremented as each object unregisters itself.
+  while (!f_unwind_stack.empty())
+    {
+      PRINTF (("* Calling dtor of %p\n", f_unwind_stack.top().f_object));
+#if CC_VERSION < 30
+      f_unwind_stack.top().f_object->destruct();
+#else
+      f_unwind_stack.top().f_object->~Destructable();
+#endif
+    }
+
+  // This Jump Environment is no longer needed, so we need to pull it off
+  // the global jump env stack.  Any new stack objects from this point
+  // on must be registed in the enclosing Jump Environment scope for the
+  // purposes of exceptions or otherwise.  The memory associated with the
+  // unwind_stack is freed when we exit the scope or throw an exception. 
+  g_jump_env_stack = f_next;
+  PRINTF (("----- <%d> Unwind complete -----\n", g_level));
+
+  // Make the current exception official (it may move in the process).
+  f_active_exception->make_current();
+
+  // Print a message about the throw point if debugging is on. 
+  if (debugging)
+    {
+      Exceptions::error_handler_t saved = Exceptions::set_error_handler (NULL);
+      Exceptions::error (NULL, Exceptions::THROW_MESSAGE);
+      Exceptions::set_error_handler (saved);
+    }
+
+  // And away we go... 
+  longjmp();
+}
+
+
+// /////////////////////////////////////////////////////////////////
+// delete_active - delete active exception, maybe move pending
+// /////////////////////////////////////////////////////////////////
+
+void
+Jump_Environment::delete_active()
+{
+  // For starters, it's no longer the current exception.
+  f_active_exception->unmake_current();
+
+  // We normally delete the current exception when it's enclosing
+  // environment is destructed, UNLESS the same exception is being
+  // rethrown to the handler above.  g_jump_env_stack points to
+  // the Jump_Environment that is unwinding.
+
+  if (f_active_exception->f_temporary &&
+      (g_jump_env_stack == NULL || f_active_exception != pending_exception()))
+    {
+      // If there's one pending we created and a current one, we are going
+      // to have to move the pending one down on our stack after
+      // deleting the current one, so we need to remember where it ends.
+      // If the pending exception == the current one, then we're just
+      // returning to the scope of a previous exception. 
+      
+      if (g_jump_env_stack != NULL &&
+	  pending_exception() != NULL &&
+	  pending_exception()->f_temporary &&
+	  pending_exception() != Exception::g_current_exception)
+	{
+	  // The length() method is only valid here! 
+	  int length = pending_exception()->length();
+	  delete f_active_exception;
+	  Exception::relocate (&g_jump_env_stack->f_active_exception,
+			       length);
+	}
+      else  // Just delete it -- no move necessary. 
+	{
+	  delete f_active_exception;
+	}
+    }
+}
+#endif /* NATIVE_EXCEPTIONS */