debug: extend 'pdb' example to optionally break on an arbitrary list of callables

neo/debug.py

@@ -11,7 +11,15 @@ The prompt is accessible through network in case that the process is daemonized:
 
 IF = 'pdb'
 if IF == 'pdb':
-    import socket, sys, threading
+    # List of (module, callables) to break at.
+    # If empty, a thread is started with a breakpoint.
+    # All breakpoints are automatically removed on the first break,
+    # or when this module is reloaded.
+    BP = (#('ZODB.Connection', 'Connection.setstate'),
+          #('ZPublisher.Publish', 'publish_module_standard'),
+         )
+
+    import errno, socket, sys, threading, weakref
     # Unfortunately, IPython does not always print to given stdout.
     #from neo.lib.debug import getPdb
     from pdb import Pdb as getPdb
@@ -55,7 +63,7 @@ if IF == 'pdb':
                 self._socket.setblocking(1)
             return False
 
-    def pdb(app_set):
+    def pdb():
         s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
         try:
             # For better security, maybe we should use a unix socket.
@@ -87,7 +95,53 @@ if IF == 'pdb':
             app_set = ()
         finally:
             del f
-    threading.Thread(target=pdb, args=(app_set,)).start()
+
+    class setupBreakPoints(list):
+
+        def __init__(self, bp_list):
+            self._lock = threading.Lock()
+            for o, name in bp_list:
+                o = __import__(o, fromlist=1)
+                x = name.split('.')
+                name = x.pop()
+                for x in x:
+                    o = getattr(o, x)
+                orig = getattr(o, name)
+                if orig.__module__ == __name__:
+                    orig.__closure__[1].cell_contents._revert()
+                    orig = getattr(o, name)
+                    assert orig.__module__ != __name__, (o, name)
+                orig = getattr(orig, '__func__', orig)
+                self.append((o, name, orig))
+                setattr(o, name, self._wrap(orig))
+                print 'BP set on', orig
+            sys.stdout.flush()
+            self._hold = weakref.ref(pdb, self._revert)
+
+        def _revert(self, *_):
+            for x in self:
+                setattr(*x)
+                print 'BP removed on', x[2]
+            sys.stdout.flush()
+            del self[:]
+
+        def _wrap(self, orig):
+            return lambda *args, **kw: self(orig, *args, **kw)
+
+        def __call__(self, orig, *args, **kw):
+            stop = False
+            with self._lock:
+                if self:
+                    stop = True
+                    self._revert()
+            if stop:
+                pdb()
+            return orig(*args, **kw)
+
+    if BP:
+        setupBreakPoints(BP)
+    else:
+        threading.Thread(target=pdb).start()
 
 elif IF == 'frames':
     import sys, traceback