diff options
author | Christian Tismer <tismer@stackless.com> | 2018-08-13 01:50:26 +0200 |
---|---|---|
committer | Christian Tismer <tismer@stackless.com> | 2018-08-21 13:50:37 +0000 |
commit | 28e82039e7b0c611f78d4b15dc7fb2ba232bb76c (patch) | |
tree | 365788a607ffa679645d20ee81c94b99269faec3 /sources/shiboken2/libshiboken/pep384impl.cpp | |
parent | 877c9be79d660fe1317a6fb46c585fb688abc21e (diff) |
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 <cristian.maureira-fredes@qt.io>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Diffstat (limited to 'sources/shiboken2/libshiboken/pep384impl.cpp')
-rw-r--r-- | sources/shiboken2/libshiboken/pep384impl.cpp | 100 |
1 files changed, 92 insertions, 8 deletions
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 <autodecref.h> 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; @@ -820,6 +815,95 @@ PepType_GetNameStr(PyTypeObject *type) /***************************************************************************** * + * 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<PyObject *>(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 * */ |