Basic plumbing for a --branch option.

4 files changed, 21 insertions, 4 deletions

diff --git a/coverage/cmdline.py b/coverage/cmdline.py
index b34c4b1d..c9b8a7fb 100644
--- a/coverage/cmdline.py
+++ b/coverage/cmdline.py
@@ -8,6 +8,10 @@ from coverage.execfile import run_python_file
 class Opts:
     """A namespace class for individual options we'll build parsers from."""
     
+    branch = optparse.Option(
+        '', '--branch', action='store_true',
+        help="Measure branch execution. HIGHLY EXPERIMENTAL!"
+        )
     directory = optparse.Option(
         '-d', '--directory', action='store',
         metavar="DIR",
@@ -78,6 +82,7 @@ class CoverageOptionParser(optparse.OptionParser, object):
             )
         self.set_defaults(
             actions=[],
+            branch=None,
             directory=None,
             help=None,
             ignore_errors=None,
@@ -251,6 +256,7 @@ CMDS = {
     'run': CmdOptionParser("execute",
         [
             Opts.append,
+            Opts.branch,
             Opts.pylib,
             Opts.parallel_mode,
             Opts.timid,
@@ -401,6 +407,7 @@ class CoverageScript:
             data_suffix = bool(options.parallel_mode),
             cover_pylib = options.pylib,
             timid = options.timid,
+            branch = options.branch,
             )
 
         if 'debug' in options.actions:
diff --git a/coverage/collector.py b/coverage/collector.py
index 3b56d241..8e304c1f 100644
--- a/coverage/collector.py
+++ b/coverage/collector.py
@@ -35,6 +35,7 @@ class PyTracer:
         self.cur_filename = None
         self.filename_stack = []
         self.last_exc_back = None
+        self.branch = False
 
     def _trace(self, frame, event, arg_unused):
         """The trace function passed to sys.settrace."""
@@ -68,6 +69,7 @@ class PyTracer:
         
     def start(self):
         """Start this Tracer."""
+        assert not self.branch
         sys.settrace(self._trace)
 
     def stop(self):
@@ -95,7 +97,7 @@ class Collector:
     # the top, and resumed when they become the top again.
     _collectors = []
 
-    def __init__(self, should_trace, timid=False):
+    def __init__(self, should_trace, timid=False, branch=False):
         """Create a collector.
         
         `should_trace` is a function, taking a filename, and returning a
@@ -107,10 +109,13 @@ class Collector:
         tracing functions make the faster more sophisticated trace function not
         operate properly.
         
+        TODO: `branch`
+        
         """
         self.should_trace = should_trace
+        self.branch = branch
         self.reset()
-        if timid:
+        if timid or branch:
             # Being timid: use the simple Python trace function.
             self._trace_class = PyTracer
         else:
@@ -142,6 +147,7 @@ class Collector:
         tracer.data = self.data
         tracer.should_trace = self.should_trace
         tracer.should_trace_cache = self.should_trace_cache
+        tracer.branch = self.branch
         tracer.start()
         self.tracers.append(tracer)
 
diff --git a/coverage/control.py b/coverage/control.py
index ba642e44..8f54a641 100644
--- a/coverage/control.py
+++ b/coverage/control.py
@@ -29,7 +29,7 @@ class coverage:
     """
 
     def __init__(self, data_file=None, data_suffix=False, cover_pylib=False,
-                auto_data=False, timid=False):
+                auto_data=False, timid=False, branch=False):
         """Create a new coverage measurement context.
         
         `data_file` is the base name of the data file to use, defaulting to
@@ -65,7 +65,7 @@ class coverage:
         # cheap hack, since the rest of the command line arguments aren't
         # recognized, but it solves some users' problems.
         timid = timid or ('--timid' in os.environ.get('COVERAGE_OPTIONS', ''))
-        self.collector = Collector(self._should_trace, timid=timid)
+        self.collector = Collector(self._should_trace, timid=timid, branch=branch)
 
         # Create the data file.
         if data_suffix:
diff --git a/coverage/tracer.c b/coverage/tracer.c
index b2389228..c318e9ed 100644
--- a/coverage/tracer.c
+++ b/coverage/tracer.c
@@ -41,6 +41,7 @@ typedef struct {
     PyObject * should_trace;

     PyObject * data;

     PyObject * should_trace_cache;

+    PyObject * branch;

     int started;

     /* The index of the last-used entry in tracenames. */

     int depth;

@@ -301,6 +302,9 @@ Tracer_members[] = {
     { "should_trace_cache", T_OBJECT, offsetof(Tracer, should_trace_cache), 0,

             PyDoc_STR("Dictionary caching should_trace results.") },

 

+    { "branch",             T_OBJECT, offsetof(Tracer, branch), 0,

+            PyDoc_STR("Should we trace branches?") },

+

     { NULL }

 };