PythonTraceFunction.java

// Copyright (c) Corporation for National Research Initiatives
package org.python.core;

class PythonTraceFunction extends TraceFunction {

    PyObject tracefunc;

    PythonTraceFunction(PyObject tracefunc) {
        this.tracefunc = tracefunc;
    }

    private TraceFunction safeCall(PyFrame frame, String label, PyObject arg) {
        synchronized (imp.class) {
            synchronized (this) {
                ThreadState ts = Py.getThreadState();
                if (ts.tracing)
                    return null;
                if (tracefunc == null)
                    return null;
                PyObject ret = null;
                try {
                    ts.tracing = true;
                    ret = tracefunc.__call__(frame, new PyString(label), arg);
                } catch (PyException exc) {
                    frame.tracefunc = null;
                    ts.systemState.tracefunc = null;
                    ts.systemState.profilefunc = null;
                    throw exc;
                } finally {
                    ts.tracing = false;
                }
                if (ret == tracefunc)
                    return this;
                if (ret == Py.None)
                    return null;
                return new PythonTraceFunction(ret);
            }
        }
    }

    public TraceFunction traceCall(PyFrame frame) {
        return safeCall(frame, "call", Py.None);
    }

    public TraceFunction traceReturn(PyFrame frame, PyObject ret) {
        return safeCall(frame, "return", ret);
    }

    public TraceFunction traceLine(PyFrame frame, int line) {
        return safeCall(frame, "line", Py.None);
    }

    public TraceFunction traceException(PyFrame frame, PyException exc) {
        return safeCall(frame, "exception", new PyTuple(new PyObject[] { exc.type, exc.value, exc.traceback }));
    }
}