1 files changed, 126 insertions, 0 deletions
diff --git a/distbuild/crashpoint.py b/distbuild/crashpoint.py
new file mode 100644
index 00000000..01bfbd6b
--- /dev/null
+++ b/distbuild/crashpoint.py
@@ -0,0 +1,126 @@
+# distbuild/crashpoint.py -- user-controlled crashing
+#
+# Copyright (C) 2014  Codethink Limited
+# 
+# This program 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; version 2 of the License.
+#
+# This program 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..
+
+
+'''Crash the application.
+
+For crash testing, it's useful to easily induce crashes, to see how the
+rest of the system manages. This module implements user-controllable
+crashes. The code will be sprinkled with calls to the ``crash_point``
+function, which crashes the process if call matches a set of user-defined
+criteria.
+
+The criteria consist of:
+
+* a filename
+* a function name
+* a maximum call count
+
+The criterion is fullfilled if ``crash_point`` is called from the named
+function defined in the named file more than the given number of times.
+Filename matching is using substrings (a filename pattern ``foo.py``
+matches an actual source file path of 
+``/usr/lib/python2.7/site-packages/distbuild/foo.py``), but function
+names must match exactly. It is not possible to match on class names
+(since that information is not available from a traceback).
+
+'''
+
+
+import logging
+import os
+import sys
+import traceback
+
+
+detailed_logging = False
+
+
+def debug(msg): # pragma: no cover
+    if detailed_logging:
+        logging.debug(msg)
+
+
+class CrashCondition(object):
+
+    def __init__(self, filename, funcname, max_calls):
+        self.filename = filename
+        self.funcname = funcname
+        self.max_calls = max_calls
+        self.called = 0
+        
+    def matches(self, filename, funcname):
+        if self.filename not in filename:
+            debug(
+                'crashpoint: filename mismatch: %s not in %s' %
+                    (repr(self.filename), repr(filename)))
+            return False
+
+        if self.funcname != funcname:
+            debug(
+                'crashpoint: funcname mismatch: %s != %s' %
+                    (self.funcname, funcname))
+            return False
+
+        debug('crashpoint: matches: %s %s' % (filename, funcname))
+        return True
+        
+    def triggered(self, filename, funcname):
+        if self.matches(filename, funcname):
+            self.called += 1
+            return self.called >= self.max_calls
+        else:
+            return False
+
+
+crash_conditions = []
+
+
+def add_crash_condition(filename, funcname, max_calls):
+    crash_conditions.append(CrashCondition(filename, funcname, max_calls))
+
+
+def add_crash_conditions(strings):
+    for s in strings:
+        words = s.split(':')
+        if len(words) != 3: # pragma: no cover
+            logging.error('Ignoring malformed crash condition: %s' % repr(s))
+        else:
+            add_crash_condition(words[0], words[1], int(words[2]))
+
+
+def clear_crash_conditions():
+    del crash_conditions[:]
+    
+    
+def crash_point(frame=None):
+    if frame is None:
+        frames = traceback.extract_stack(limit=2)
+        frame = frames[0]
+
+    filename, lineno, funcname, text = frame
+    
+    for condition in crash_conditions:
+        if condition.triggered(filename, funcname):
+            logging.critical(
+                'Crash triggered from %s:%s:%s' % (filename, lineno, funcname))
+            sys.exit(255)
+        else:
+            debug(
+                'Crash not triggered by %s:%s:%s' %
+                    (filename, lineno, funcname))
+