contrib/fuzz/dirstate.cc

testing: introduce util function to synchronize concurrent commands on files

This is an extension of mechanisms that the tests have been using for a while.
To be able to also control the execution in Rust, we introduce utility to
perform such `wait_on_file` logic based on some configuration value.

This will be used in the tests introduced in the next changesets.

#include <Python.h>
#include <assert.h>
#include <stdlib.h>
#include <unistd.h>

#include <string>

#include "pyutil.h"

extern "C" {

static PYCODETYPE *code;

extern "C" int LLVMFuzzerInitialize(int *argc, char ***argv)
{
	contrib::initpy(*argv[0]);
	code = (PYCODETYPE *)Py_CompileString(R"py(
try:
    dmap = {}
    copymap = {}
    p = parsers.parse_dirstate(dmap, copymap, data)
except Exception as e:
    pass
    # uncomment this print if you're editing this Python code
    # to debug failures.
    # print e
)py",
	                                      "fuzzer", Py_file_input);
	return 0;
}

int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)
{
	PyObject *text =
	    PyBytes_FromStringAndSize((const char *)Data, (Py_ssize_t)Size);
	PyObject *locals = PyDict_New();
	PyDict_SetItemString(locals, "data", text);
	PyObject *res = PyEval_EvalCode(code, contrib::pyglobals(), locals);
	if (!res) {
		PyErr_Print();
	}
	Py_XDECREF(res);
	Py_DECREF(locals);
	Py_DECREF(text);
	return 0; // Non-zero return values are reserved for future use.
}
}