WIPnedbat/fix-c-tracer

2 files changed, 41 insertions, 0 deletions

diff --git a/coverage/collector.py b/coverage/collector.py
index 73babf44..992c8578 100644
--- a/coverage/collector.py
+++ b/coverage/collector.py
@@ -15,6 +15,10 @@ from coverage.pytracer import PyTracer
 
 os = isolate_module(os)
 
+def debugmsg(msg, flush=True):
+    return
+    with open("/tmp/debug.txt", "a") as f:
+        print(msg, file=f, flush=True)
 
 try:
     # Use the C extension code when we can, for speed.
@@ -233,7 +237,9 @@ class Collector:
 
     def _start_tracer(self):
         """Start a new Tracer object, and store it in self.tracers."""
+        debugmsg("Making a new tracer")
         tracer = self._trace_class()
+        debugmsg("Made a new tracer")
         tracer.data = self.data
         tracer.trace_arcs = self.branch
         tracer.should_trace = self.should_trace
@@ -261,7 +267,9 @@ class Collector:
         if hasattr(tracer, 'disable_plugin'):
             tracer.disable_plugin = self.disable_plugin
 
+        debugmsg("about to start")
         fn = tracer.start()
+        debugmsg("started")
         self.tracers.append(tracer)
 
         return fn
@@ -303,7 +311,9 @@ class Collector:
 
         try:
             # Install the tracer on this thread.
+            debugmsg("About to start", flush=True)
             fn = self._start_tracer()
+            debugmsg("Started", flush=True)
         except:
             if self._collectors:
                 self._collectors[-1].resume()
@@ -311,7 +321,9 @@ class Collector:
 
         # If _start_tracer succeeded, then we add ourselves to the global
         # stack of collectors.
+        debugmsg("About to append", flush=True)
         self._collectors.append(self)
+        debugmsg("Appended", flush=True)
 
         # Replay all the events from fullcoverage into the new trace function.
         for args in traces0:
diff --git a/coverage/ctracer/tracer.c b/coverage/ctracer/tracer.c
index 00d9f106..80601c14 100644
--- a/coverage/ctracer/tracer.c
+++ b/coverage/ctracer/tracer.c
@@ -781,12 +781,40 @@ CTracer_handle_exception(CTracer *self, PyFrameObject *frame)
     return RET_OK;
 }
 
+static CTracer *self_stack[1000];
+static int self_stack_top = -1;
+static CTracer *the_tracer;
+
 /*
  * The Trace Function
  */
 static int
 CTracer_trace(CTracer *self, PyFrameObject *frame, int what, PyObject *arg_unused)
 {
+    switch (what) {
+    case PyTrace_CALL:
+        if (self_stack_top == -1) {
+            self_stack_top = 0;
+            self = the_tracer;
+        }
+        else {
+            self_stack_top++;
+        }
+        self_stack[self_stack_top] = self;
+        break;
+
+    case PyTrace_RETURN:
+        if (self_stack_top >= 0) {
+            self_stack_top--;
+        }
+        break;
+    }
+
+    if (self_stack_top == -1) {
+        return RET_OK;
+    }
+    self = self_stack[self_stack_top];
+
     int ret = RET_ERROR;
 
     #if DO_NOTHING
@@ -990,6 +1018,7 @@ CTracer_start(CTracer *self, PyObject *args_unused)
 
     /* start() returns a trace function usable with sys.settrace() */
     Py_INCREF(self);
+    the_tracer = self;
     return (PyObject *)self;
 }