From 28e82039e7b0c611f78d4b15dc7fb2ba232bb76c Mon Sep 17 00:00:00 2001 From: Christian Tismer Date: Mon, 13 Aug 2018 01:50:26 +0200 Subject: Implement Proper Name Mangling When types have attributes starting with two underscores but ending with at most one, Python uses name mangling to create a unique private variable. PySide needs to obey this rule in the tp_getattro methods. We implemented it as an optimized _Pep_PrivateMangle function that solves the problem internally without exposing the _Py_Mangle function. Remark: I think the exclusion of the _Py_Mangle function is another oversight in the Limited API. Task-number: PYSIDE-772 Change-Id: I0bfc2418dae439e963a16e37443f2099c6980696 Reviewed-by: Cristian Maureira-Fredes Reviewed-by: Friedemann Kleint --- sources/shiboken2/libshiboken/pep384impl.cpp | 100 ++++++++++++++++++++++++--- sources/shiboken2/libshiboken/pep384impl.h | 9 +++ sources/shiboken2/libshiboken/sbkpython.h | 6 ++ 3 files changed, 107 insertions(+), 8 deletions(-) (limited to 'sources/shiboken2/libshiboken') diff --git a/sources/shiboken2/libshiboken/pep384impl.cpp b/sources/shiboken2/libshiboken/pep384impl.cpp index e1dd7518f..39fdc37ad 100644 --- a/sources/shiboken2/libshiboken/pep384impl.cpp +++ b/sources/shiboken2/libshiboken/pep384impl.cpp @@ -38,6 +38,7 @@ ****************************************************************************/ #include "pep384impl.h" +#include extern "C" { @@ -465,7 +466,7 @@ _PepUnicode_AsString(PyObject *str) /* * We need to keep the string alive but cannot borrow the Python object. * Ugly easy way out: We re-code as an interned bytes string. This - * produces a pseudo-leak as long there are new strings. + * produces a pseudo-leak as long as there are new strings. * Typically, this function is used for name strings, and the dict size * will not grow so much. */ @@ -765,13 +766,7 @@ PepFunction_Get(PyObject *ob, const char *name) return ret; } -/***************************************************************************** - * - * Support for funcobject.h - * - */ - -// this became necessary after Windows was activated. +// This became necessary after Windows was activated. PyTypeObject *PepFunction_TypePtr = NULL; @@ -818,6 +813,95 @@ PepType_GetNameStr(PyTypeObject *type) return ret; } +/***************************************************************************** + * + * Extra support for name mangling + * + */ + +#ifdef Py_LIMITED_API +// We keep these definitions local, because they don't work in Python 2. +#define PyUnicode_GET_LENGTH(op) PyUnicode_GetLength((PyObject *)(op)) +#define PyUnicode_READ_CHAR(u, i) PyUnicode_ReadChar((PyObject *)(u), (i)) +#endif + +PyObject * +_Pep_PrivateMangle(PyObject *self, PyObject *name) +{ + /* + * Name mangling: __private becomes _classname__private. + * This function is modelled after _Py_Mangle, but is optimized + * a little for our purpose. + */ +#if PY_VERSION_HEX < 0X03000000 + const char *namestr = PyString_AsString(name); + if (namestr == NULL || namestr[0] != '_' || namestr[1] != '_') { + Py_INCREF(name); + return name; + } + size_t nlen = strlen(namestr); + /* Don't mangle __id__ or names with dots. */ + if ((namestr[nlen-1] == '_' && namestr[nlen-2] == '_') + || strchr(namestr, '.')) { + Py_INCREF(name); + return name; + } +#else + if (PyUnicode_READ_CHAR(name, 0) != '_' || + PyUnicode_READ_CHAR(name, 1) != '_') { + Py_INCREF(name); + return name; + } + size_t nlen = PyUnicode_GET_LENGTH(name); + /* Don't mangle __id__ or names with dots. */ + if ((PyUnicode_READ_CHAR(name, nlen-1) == '_' && + PyUnicode_READ_CHAR(name, nlen-2) == '_') || + PyUnicode_FindChar(name, '.', 0, nlen, 1) != -1) { + Py_INCREF(name); + return name; + } +#endif + Shiboken::AutoDecRef privateobj(PyObject_GetAttrString( + reinterpret_cast(Py_TYPE(self)), "__name__")); +#ifndef Py_LIMITED_API + return _Py_Mangle(privateobj, name); +#else + // For some reason, _Py_Mangle is not in the Limited API. Why? + size_t plen = PyUnicode_GET_LENGTH(privateobj); + /* Strip leading underscores from class name */ + size_t ipriv = 0; + while (PyUnicode_READ_CHAR(privateobj, ipriv) == '_') + ipriv++; + if (ipriv == plen) { + Py_INCREF(name); + return name; /* Don't mangle if class is just underscores */ + } + plen -= ipriv; + + if (plen + nlen >= PY_SSIZE_T_MAX - 1) { + PyErr_SetString(PyExc_OverflowError, + "private identifier too large to be mangled"); + return NULL; + } + size_t const amount = ipriv + 1 + plen + nlen; + size_t const big_stack = 1000; + wchar_t bigbuf[big_stack]; + wchar_t *resbuf = amount <= big_stack ? bigbuf : (wchar_t *)malloc(sizeof(wchar_t) * amount); + if (!resbuf) + return 0; + /* ident = "_" + priv[ipriv:] + ident # i.e. 1+plen+nlen bytes */ + resbuf[0] = '_'; + if (PyUnicode_AsWideChar(privateobj, resbuf + 1, ipriv + plen) < 0) + return 0; + if (PyUnicode_AsWideChar(name, resbuf + ipriv + plen + 1, nlen) < 0) + return 0; + PyObject *result = PyUnicode_FromWideChar(resbuf + ipriv, 1 + plen + nlen); + if (amount > big_stack) + free(resbuf); + return result; +#endif // Py_LIMITED_API +} + /***************************************************************************** * * Module Initialization diff --git a/sources/shiboken2/libshiboken/pep384impl.h b/sources/shiboken2/libshiboken/pep384impl.h index d06947f06..b566a6218 100644 --- a/sources/shiboken2/libshiboken/pep384impl.h +++ b/sources/shiboken2/libshiboken/pep384impl.h @@ -450,6 +450,15 @@ LIBSHIBOKEN_API PyObject *PyTime_FromTime( #endif /* Py_LIMITED_API */ +/***************************************************************************** + * + * Extra support for name mangling + * + */ + +// PYSIDE-772: This function supports the fix, but is not meant as public. +LIBSHIBOKEN_API PyObject *_Pep_PrivateMangle(PyObject *self, PyObject *name); + /***************************************************************************** * * Extra support for signature.cpp diff --git a/sources/shiboken2/libshiboken/sbkpython.h b/sources/shiboken2/libshiboken/sbkpython.h index fbac016eb..29e25605a 100644 --- a/sources/shiboken2/libshiboken/sbkpython.h +++ b/sources/shiboken2/libshiboken/sbkpython.h @@ -42,7 +42,13 @@ #include "sbkversion.h" +/* + * Python 2 has function _Py_Mangle directly in Python.h . + * This creates wrong language binding unless we define 'extern "C"' here. + */ +extern "C" { #include +} #include // Now we have the usual variables from Python.h . #include "python25compat.h" -- cgit v1.2.3