1 files changed, 89 insertions, 0 deletions
diff --git a/grc/base/Element.py b/grc/base/Element.py
new file mode 100644
index 000000000..a57090f3b
--- /dev/null
+++ b/grc/base/Element.py
@@ -0,0 +1,89 @@
+"""
+Copyright 2008, 2009 Free Software Foundation, Inc.
+This file is part of GNU Radio
+
+GNU Radio Companion is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License
+as published by the Free Software Foundation; either version 2
+of the License, or (at your option) any later version.
+
+GNU Radio Companion is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+"""
+
+class Element(object):
+
+	def __init__(self, parent=None):
+		self._parent = parent
+
+	##################################################
+	# Element Validation API
+	##################################################
+	def validate(self):
+		"""
+		Validate this element and call validate on all children.
+		Call this base method before adding error messages in the subclass.
+		"""
+		self._error_messages = list()
+		for child in self.get_children(): child.validate()
+
+	def is_valid(self):
+		"""
+		Is this element valid?
+		@return true when the element is enabled and has no error messages
+		"""
+		return not self.get_error_messages() or not self.get_enabled()
+
+	def add_error_message(self, msg):
+		"""
+		Add an error message to the list of errors.
+		@param msg the error message string
+		"""
+		self._error_messages.append(msg)
+
+	def get_error_messages(self):
+		"""
+		Get the list of error messages from this element and all of its children.
+		Do not include the error messages from disabled children.
+		Cleverly indent the children error messages for printing purposes.
+		@return a list of error message strings
+		"""
+		error_messages = list(self._error_messages) #make a copy
+		for child in filter(lambda c: c.get_enabled(), self.get_children()):
+			for msg in child.get_error_messages():
+				error_messages.append("%s:\n\t%s"%(child, msg.replace("\n", "\n\t")))
+		return error_messages
+
+	def rewrite(self):
+		"""
+		Rewrite this element and call rewrite on all children.
+		Call this base method before rewriting the element.
+		"""
+		for child in self.get_children(): child.rewrite()
+
+	def get_enabled(self): return True
+
+	##############################################
+	## Tree-like API
+	##############################################
+	def get_parent(self): return self._parent
+	def get_children(self): return list()
+
+	##############################################
+	## Type testing methods
+	##############################################
+	def is_element(self): return True
+	def is_platform(self): return False
+	def is_flow_graph(self): return False
+	def is_connection(self): return False
+	def is_block(self): return False
+	def is_source(self): return False
+	def is_sink(self): return False
+	def is_port(self): return False
+	def is_param(self): return False