revlog: implement changelogv2 packing and unpacking in C
This introduces a C implementation of changelogv2 records packing and unpacking
operations matching the pure Python counterpart, similarly to what we already
have for revlogv1 and revlogv2.
This is also necessary to access changelogv2 record fields from future Rust
code without going through the Python part, which would annihilate any
performance benefit.
Differential Revision: https://phab.mercurial-scm.org/D12178
#include "pyutil.h"
#include <iostream>
#include <string>
namespace contrib
{
#if PY_MAJOR_VERSION >= 3
#define HG_FUZZER_PY3 1
PyMODINIT_FUNC PyInit_parsers(void);
#else
PyMODINIT_FUNC initparsers(void);
#endif
static char cpypath[8192] = "\0";
static PyObject *mainmod;
static PyObject *globals;
void initpy(const char *cselfpath)
{
#ifdef HG_FUZZER_PY3
const std::string subdir = "/sanpy/lib/python3.8";
#else
const std::string subdir = "/sanpy/lib/python2.7";
#endif
/* HACK ALERT: we need a full Python installation built without
pymalloc and with ASAN, so we dump one in
$OUT/sanpy/lib/python2.7. This helps us wire that up. */
std::string selfpath(cselfpath);
std::string pypath;
auto pos = selfpath.rfind("/");
if (pos == std::string::npos) {
char wd[8192];
if (!getcwd(wd, 8192)) {
std::cerr << "Failed to call getcwd: errno " << errno
<< std::endl;
exit(1);
}
pypath = std::string(wd) + subdir;
} else {
pypath = selfpath.substr(0, pos) + subdir;
}
strncpy(cpypath, pypath.c_str(), pypath.size());
setenv("PYTHONPATH", cpypath, 1);
setenv("PYTHONNOUSERSITE", "1", 1);
/* prevent Python from looking up users in the fuzz environment */
setenv("PYTHONUSERBASE", cpypath, 1);
#ifdef HG_FUZZER_PY3
std::wstring wcpypath(pypath.begin(), pypath.end());
Py_SetPythonHome(wcpypath.c_str());
#else
Py_SetPythonHome(cpypath);
#endif
Py_InitializeEx(0);
mainmod = PyImport_AddModule("__main__");
globals = PyModule_GetDict(mainmod);
#ifdef HG_FUZZER_PY3
PyObject *mod = PyInit_parsers();
#else
initparsers();
PyObject *mod = PyImport_ImportModule("parsers");
#endif
PyDict_SetItemString(globals, "parsers", mod);
}
PyObject *pyglobals()
{
return globals;
}
} // namespace contrib