exceptions.c

python s60 1.4.5版本的源代码

/* Portions Copyright (c) 2005 Nokia Corporation */
/* This module provides the suite of standard class-based exceptions for
 * Python's builtin module.  This is a complete C implementation of what,
 * in Python 1.5.2, was contained in the exceptions.py module.  The problem
 * there was that if exceptions.py could not be imported for some reason,
 * the entire interpreter would abort.
 *
 * By moving the exceptions into C and statically linking, we can guarantee
 * that the standard exceptions will always be available.
 *
 * history:
 * 98-08-19    fl   created (for pyexe)
 * 00-02-08    fl   updated for 1.5.2
 * 26-May-2000 baw  vetted for Python 1.6
 *
 * written by Fredrik Lundh
 * modifications, additions, cleanups, and proofreading by Barry Warsaw
 *
 * Copyright (c) 1998-2000 by Secret Labs AB.  All rights reserved.
 */

#include "Python.h"
#include "osdefs.h"

/* Caution:  MS Visual C++ 6 errors if a single string literal exceeds
 * 2Kb.  So the module docstring has been broken roughly in half, using
 * compile-time literal concatenation.
 */
const static char
module__doc__[] =
#ifdef SYMBIAN
"Python's standard exception class hierarchy.";
#else
"Python's standard exception class hierarchy.\n\
\n\
Before Python 1.5, the standard exceptions were all simple string objects.\n\
In Python 1.5, the standard exceptions were converted to classes organized\n\
into a relatively flat hierarchy.  String-based standard exceptions were\n\
optional, or used as a fallback if some problem occurred while importing\n\
the exception module.  With Python 1.6, optional string-based standard\n\
exceptions were removed (along with the -X command line flag).\n\
\n\
The class exceptions were implemented in such a way as to be almost\n\
completely backward compatible.  Some tricky uses of IOError could\n\
potentially have broken, but by Python 1.6, all of these should have\n\
been fixed.  As of Python 1.6, the class-based standard exceptions are\n\
now implemented in C, and are guaranteed to exist in the Python\n\
interpreter.\n\
\n\
Here is a rundown of the class hierarchy.  The classes found here are\n\
inserted into both the exceptions module and the `built-in' module.  It is\n\
recommended that user defined class based exceptions be derived from the\n\
`Exception' class, although this is currently not enforced.\n"
        /* keep string pieces "small" */
"\n\
Exception\n\
 |\n\
 +-- SystemExit\n\
 +-- StopIteration\n\
 +-- StandardError\n\
 |    |\n\
 |    +-- KeyboardInterrupt\n\
 |    +-- ImportError\n\
 |    +-- EnvironmentError\n\
 |    |    |\n\
 |    |    +-- IOError\n\
 |    |    +-- OSError\n\
 |    |         |\n\
 |    |         +-- WindowsError\n\
 |    |\n\
 |    +-- EOFError\n\
 |    +-- RuntimeError\n\
 |    |    |\n\
 |    |    +-- NotImplementedError\n\
 |    |\n\
 |    +-- NameError\n\
 |    |    |\n\
 |    |    +-- UnboundLocalError\n\
 |    |\n\
 |    +-- AttributeError\n\
 |    +-- SyntaxError\n\
 |    |    |\n\
 |    |    +-- IndentationError\n\
 |    |         |\n\
 |    |         +-- TabError\n\
 |    |\n\
 |    +-- TypeError\n\
 |    +-- AssertionError\n\
 |    +-- LookupError\n\
 |    |    |\n\
 |    |    +-- IndexError\n\
 |    |    +-- KeyError\n\
 |    |\n\
 |    +-- ArithmeticError\n\
 |    |    |\n\
 |    |    +-- OverflowError\n\
 |    |    +-- ZeroDivisionError\n\
 |    |    +-- FloatingPointError\n\
 |    |\n\
 |    +-- ValueError\n\
 |    |    |\n\
 |    |    +-- UnicodeError\n\
 |    |\n\
 |    +-- ReferenceError\n\
 |    +-- SystemError\n\
 |    +-- MemoryError\n\
 |\n\
 +---Warning\n\
      |\n\
      +-- UserWarning\n\
      +-- DeprecationWarning\n\
      +-- SyntaxWarning\n\
      +-- OverflowWarning\n\
      +-- RuntimeWarning";
#endif /* not def SYMBIAN */

/* Helper function for populating a dictionary with method wrappers. */
static int
populate_methods(PyObject *klass, PyObject *dict, PyMethodDef *methods)
{
    if (!methods)
        return 0;

    while (methods->ml_name) {
        /* get a wrapper for the built-in function */
        PyObject *func = PyCFunction_New(methods, NULL);
        PyObject *meth;
        int status;

        if (!func)
            return -1;

        /* turn the function into an unbound method */
        if (!(meth = PyMethod_New(func, NULL, klass))) {
            Py_DECREF(func);
            return -1;
        }

        /* add method to dictionary */
        status = PyDict_SetItemString(dict, methods->ml_name, meth);
        Py_DECREF(meth);
        Py_DECREF(func);

        /* stop now if an error occurred, otherwise do the next method */
        if (status)
            return status;

        methods++;
    }
    return 0;
}



/* This function is used to create all subsequent exception classes. */
static int
make_class(PyObject **klass, PyObject *base,
           char *name, PyMethodDef *methods,
           char *docstr)
{
    PyObject *dict = PyDict_New();
    PyObject *str = NULL;
    int status = -1;

    if (!dict)
        return -1;

    /* If an error occurs from here on, goto finally instead of explicitly
     * returning NULL.
     */

    if (docstr) {
        if (!(str = PyString_FromString(docstr)))
            goto finally;
        if (PyDict_SetItemString(dict, "__doc__", str))
            goto finally;
    }

    if (!(*klass = PyErr_NewException(name, base, dict)))
        goto finally;

    if (populate_methods(*klass, dict, methods)) {
        Py_DECREF(*klass);
        *klass = NULL;
        goto finally;
    }

    status = 0;

  finally:
    Py_XDECREF(dict);
    Py_XDECREF(str);
    return status;
}


/* Use this for *args signatures, otherwise just use PyArg_ParseTuple() */
static PyObject *
get_self(PyObject *args)
{
    PyObject *self = PyTuple_GetItem(args, 0);
    if (!self) {
        /* Watch out for being called to early in the bootstrapping process */
        if (PyExc_TypeError) {
            PyErr_SetString(PyExc_TypeError,
             "unbound method must be called with instance as first argument");
        }
        return NULL;
    }
    return self;
}



/* Notes on bootstrapping the exception classes.
 *
 * First thing we create is the base class for all exceptions, called
 * appropriately enough: Exception.  Creation of this class makes no
 * assumptions about the existence of any other exception class -- except
 * for TypeError, which can conditionally exist.
 *
 * Next, StandardError is created (which is quite simple) followed by
 * TypeError, because the instantiation of other exceptions can potentially
 * throw a TypeError.  Once these exceptions are created, all the others
 * can be created in any order.  See the static exctable below for the
 * explicit bootstrap order.
 *
 * All classes after Exception can be created using PyErr_NewException().
 */

const static char
Exception__doc__[] = "Common base class for all exceptions.";


static PyObject *
Exception__init__(PyObject *self, PyObject *args)
{
    int status;

    if (!(self = get_self(args)))
        return NULL;

    /* set args attribute */
    /* XXX size is only a hint */
    args = PySequence_GetSlice(args, 1, PySequence_Size(args));
    if (!args)
        return NULL;
    status = PyObject_SetAttrString(self, "args", args);
    Py_DECREF(args);
    if (status < 0)
        return NULL;

    Py_INCREF(Py_None);
    return Py_None;
}


static PyObject *
Exception__str__(PyObject *self, PyObject *args)
{
    PyObject *out;

    if (!PyArg_ParseTuple(args, "O:__str__", &self))
        return NULL;

    args = PyObject_GetAttrString(self, "args");
    if (!args)
        return NULL;

    switch (PySequence_Size(args)) {
    case 0:
        out = PyString_FromString("");
        break;
    case 1:
    {
        PyObject *tmp = PySequence_GetItem(args, 0);
        if (tmp) {
            out = PyObject_Str(tmp);
            Py_DECREF(tmp);
        }
        else
            out = NULL;
        break;
    }
    case -1:
        PyErr_Clear();
        /* Fall through */
    default:
        out = PyObject_Str(args);
        break;
    }

    Py_DECREF(args);
    return out;
}


static PyObject *
Exception__getitem__(PyObject *self, PyObject *args)
{
    PyObject *out;
    PyObject *index;

    if (!PyArg_ParseTuple(args, "OO:__getitem__", &self, &index))
        return NULL;

    args = PyObject_GetAttrString(self, "args");
    if (!args)
        return NULL;

    out = PyObject_GetItem(args, index);
    Py_DECREF(args);
    return out;
}


const static PyMethodDef
Exception_methods[] = {
    /* methods for the Exception class */
    { "__getitem__", Exception__getitem__, METH_VARARGS},
    { "__str__",     Exception__str__, METH_VARARGS},
    { "__init__",    Exception__init__, METH_VARARGS},
    { NULL, NULL }
};


static int
make_Exception(char *modulename)
{
    PyObject *dict = PyDict_New();
    PyObject *str = NULL;
    PyObject *name = NULL;
    int status = -1;

    if (!dict)
        return -1;

    /* If an error occurs from here on, goto finally instead of explicitly
     * returning NULL.
     */

    if (!(str = PyString_FromString(modulename)))
        goto finally;
    if (PyDict_SetItemString(dict, "__module__", str))
        goto finally;
    Py_DECREF(str);
    if (!(str = PyString_FromString(Exception__doc__)))
        goto finally;
    if (PyDict_SetItemString(dict, "__doc__", str))
        goto finally;

    if (!(name = PyString_FromString("Exception")))
        goto finally;

    if (!(PyExc_Exception = PyClass_New(NULL, dict, name)))
        goto finally;

    /* Now populate the dictionary with the method suite */
    // XXX:CW32
    if (populate_methods(PyExc_Exception, dict, (PyMethodDef *)Exception_methods))
        /* Don't need to reclaim PyExc_Exception here because that'll
         * happen during interpreter shutdown.
         */
        goto finally;

    status = 0;

  finally:
    Py_XDECREF(dict);
    Py_XDECREF(str);
    Py_XDECREF(name);
    return status;
}



const static char
StandardError__doc__[] = "Base class for all standard Python exceptions.";

const static char
TypeError__doc__[] = "Inappropriate argument type.";

const static char
StopIteration__doc__[] = "Signal the end from iterator.next().";



const static char
SystemExit__doc__[] = "Request to exit from the interpreter.";


static PyObject *
SystemExit__init__(PyObject *self, PyObject *args)
{
    PyObject *code;
    int status;

    if (!(self = get_self(args)))
        return NULL;

    /* Set args attribute. */
    if (!(args = PySequence_GetSlice(args, 1, PySequence_Size(args))))
        return NULL;

    status = PyObject_SetAttrString(self, "args", args);
    if (status < 0) {
        Py_DECREF(args);
        return NULL;
    }

    /* set code attribute */
    switch (PySequence_Size(args)) {
    case 0:
        Py_INCREF(Py_None);
        code = Py_None;
        break;
    case 1:
        code = PySequence_GetItem(args, 0);
        break;
    case -1:
        PyErr_Clear();
        /* Fall through */
    default:
        Py_INCREF(args);
        code = args;
        break;
    }

    status = PyObject_SetAttrString(self, "code", code);
    Py_DECREF(code);
    Py_DECREF(args);
    if (status < 0)
        return NULL;

    Py_INCREF(Py_None);
    return Py_None;
}


const static PyMethodDef SystemExit_methods[] = {
    { "__init__", SystemExit__init__, METH_VARARGS},
    {NULL, NULL}
};



const static char
KeyboardInterrupt__doc__[] = "Program interrupted by user.";

const static char
ImportError__doc__[] =
"Import can't find module, or can't find name in module.";



const static char
EnvironmentError__doc__[] = "Base class for I/O related errors.";


static PyObject *
EnvironmentError__init__(PyObject *self, PyObject *args)
{
    PyObject *item0 = NULL;
    PyObject *item1 = NULL;