Add special treatment for external codeblocks.

- Support zero-sized codeblocks
- Add a flag to ignore external blocks in flowchart generation.

sark/codeblock.py

@@ -64,11 +64,14 @@ def __eq__(self, other):
 
 
 class FlowChart(idaapi.FlowChart):
- def __init__(self, f=None, bounds=None, flags=idaapi.FC_PREDS):
+ def __init__(self, f=None, bounds=None, flags=idaapi.FC_PREDS, ignore_external=False):
  if f is None and bounds is None:
  f = idaapi.get_screen_ea()
  if f is not None:
  f = get_func(f)
+ if ignore_external:
+ flags |= idaapi.FC_NOEXT
+
  super(FlowChart, self).__init__(f=f, bounds=bounds, flags=flags)
 
  def _getitem(self, index):
@@ -88,6 +91,8 @@ def get_codeblock(ea=None):
  ea = idaapi.get_screen_ea()
  flowchart_ = get_flowchart(ea)
  for code_block in flowchart_:
+ if code_block.startEA == ea: # External blocks can be zero-sized.
+ return code_block
  if code_block.startEA <= ea < code_block.endEA:
  return code_block
 
@@ -97,11 +102,11 @@ def get_block_start(ea):
  return get_codeblock(ea).startEA
 
 
-def get_nx_graph(ea):
+def get_nx_graph(ea, ignore_external=False):
  """Convert an IDA flowchart to a NetworkX graph."""
  nx_graph = networkx.DiGraph()
  func = idaapi.get_func(ea)
- flowchart = FlowChart(func)
+ flowchart = FlowChart(func, ignore_external=ignore_external)
  for block in flowchart:
  # Make sure all nodes are added (including edge-less nodes)
  nx_graph.add_node(block.startEA)