334 lines
8.4 KiB
C
334 lines
8.4 KiB
C
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/* Frame object implementation */
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#include "Python.h"
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#include "compile.h"
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#include "frameobject.h"
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#include "opcode.h"
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#include "structmember.h"
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#define OFF(x) offsetof(PyFrameObject, x)
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static struct memberlist frame_memberlist[] = {
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{"f_back", T_OBJECT, OFF(f_back), RO},
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{"f_code", T_OBJECT, OFF(f_code), RO},
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{"f_builtins", T_OBJECT, OFF(f_builtins),RO},
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{"f_globals", T_OBJECT, OFF(f_globals), RO},
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{"f_locals", T_OBJECT, OFF(f_locals), RO},
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{"f_lasti", T_INT, OFF(f_lasti), RO},
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{"f_lineno", T_INT, OFF(f_lineno), RO},
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{"f_restricted",T_INT, OFF(f_restricted),RO},
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{"f_trace", T_OBJECT, OFF(f_trace)},
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{"f_exc_type", T_OBJECT, OFF(f_exc_type)},
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{"f_exc_value", T_OBJECT, OFF(f_exc_value)},
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{"f_exc_traceback", T_OBJECT, OFF(f_exc_traceback)},
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{NULL} /* Sentinel */
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};
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static PyObject *
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frame_getattr(PyFrameObject *f, char *name)
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{
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if (strcmp(name, "f_locals") == 0)
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PyFrame_FastToLocals(f);
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return PyMember_Get((char *)f, frame_memberlist, name);
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}
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static int
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frame_setattr(PyFrameObject *f, char *name, PyObject *value)
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{
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return PyMember_Set((char *)f, frame_memberlist, name, value);
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}
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/* Stack frames are allocated and deallocated at a considerable rate.
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In an attempt to improve the speed of function calls, we maintain a
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separate free list of stack frames (just like integers are
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allocated in a special way -- see intobject.c). When a stack frame
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is on the free list, only the following members have a meaning:
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ob_type == &Frametype
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f_back next item on free list, or NULL
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f_nlocals number of locals
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f_stacksize size of value stack
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Note that the value and block stacks are preserved -- this can save
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another malloc() call or two (and two free() calls as well!).
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Also note that, unlike for integers, each frame object is a
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malloc'ed object in its own right -- it is only the actual calls to
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malloc() that we are trying to save here, not the administration.
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After all, while a typical program may make millions of calls, a
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call depth of more than 20 or 30 is probably already exceptional
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unless the program contains run-away recursion. I hope.
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*/
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static PyFrameObject *free_list = NULL;
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static void
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frame_dealloc(PyFrameObject *f)
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{
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int i;
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PyObject **fastlocals;
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Py_TRASHCAN_SAFE_BEGIN(f)
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/* Kill all local variables */
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fastlocals = f->f_localsplus;
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for (i = f->f_nlocals; --i >= 0; ++fastlocals) {
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Py_XDECREF(*fastlocals);
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}
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Py_XDECREF(f->f_back);
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Py_XDECREF(f->f_code);
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Py_XDECREF(f->f_builtins);
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Py_XDECREF(f->f_globals);
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Py_XDECREF(f->f_locals);
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Py_XDECREF(f->f_trace);
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Py_XDECREF(f->f_exc_type);
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Py_XDECREF(f->f_exc_value);
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Py_XDECREF(f->f_exc_traceback);
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f->f_back = free_list;
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free_list = f;
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Py_TRASHCAN_SAFE_END(f)
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}
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PyTypeObject PyFrame_Type = {
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PyObject_HEAD_INIT(&PyType_Type)
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0,
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"frame",
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sizeof(PyFrameObject),
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0,
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(destructor)frame_dealloc, /*tp_dealloc*/
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0, /*tp_print*/
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(getattrfunc)frame_getattr, /*tp_getattr*/
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(setattrfunc)frame_setattr, /*tp_setattr*/
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0, /*tp_compare*/
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0, /*tp_repr*/
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0, /*tp_as_number*/
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0, /*tp_as_sequence*/
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0, /*tp_as_mapping*/
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};
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PyFrameObject *
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PyFrame_New(PyThreadState *tstate, PyCodeObject *code,
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PyObject *globals, PyObject *locals)
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{
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PyFrameObject *back = tstate->frame;
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static PyObject *builtin_object;
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PyFrameObject *f;
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PyObject *builtins;
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int extras;
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if (builtin_object == NULL) {
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builtin_object = PyString_InternFromString("__builtins__");
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if (builtin_object == NULL)
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return NULL;
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}
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if ((back != NULL && !PyFrame_Check(back)) ||
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code == NULL || !PyCode_Check(code) ||
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globals == NULL || !PyDict_Check(globals) ||
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(locals != NULL && !PyDict_Check(locals))) {
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PyErr_BadInternalCall();
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return NULL;
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}
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extras = code->co_stacksize + code->co_nlocals;
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if (back == NULL || back->f_globals != globals) {
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builtins = PyDict_GetItem(globals, builtin_object);
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if (builtins != NULL && PyModule_Check(builtins))
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builtins = PyModule_GetDict(builtins);
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}
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else {
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/* If we share the globals, we share the builtins.
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Save a lookup and a call. */
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builtins = back->f_builtins;
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}
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if (builtins != NULL && !PyDict_Check(builtins))
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builtins = NULL;
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if (free_list == NULL) {
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/* PyObject_New is inlined */
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f = (PyFrameObject *)
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PyObject_MALLOC(sizeof(PyFrameObject) +
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extras*sizeof(PyObject *));
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if (f == NULL)
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return (PyFrameObject *)PyErr_NoMemory();
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PyObject_INIT(f, &PyFrame_Type);
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}
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else {
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f = free_list;
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free_list = free_list->f_back;
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if (f->f_nlocals + f->f_stacksize < extras) {
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f = (PyFrameObject *)
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PyObject_REALLOC(f, sizeof(PyFrameObject) +
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extras*sizeof(PyObject *));
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if (f == NULL)
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return (PyFrameObject *)PyErr_NoMemory();
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}
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else
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extras = f->f_nlocals + f->f_stacksize;
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PyObject_INIT(f, &PyFrame_Type);
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}
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if (builtins == NULL) {
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/* No builtins! Make up a minimal one. */
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builtins = PyDict_New();
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if (builtins == NULL || /* Give them 'None', at least. */
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PyDict_SetItemString(builtins, "None", Py_None) < 0) {
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Py_DECREF(f);
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return NULL;
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}
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}
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else
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Py_XINCREF(builtins);
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f->f_builtins = builtins;
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Py_XINCREF(back);
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f->f_back = back;
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Py_INCREF(code);
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f->f_code = code;
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Py_INCREF(globals);
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f->f_globals = globals;
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if (code->co_flags & CO_NEWLOCALS) {
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if (code->co_flags & CO_OPTIMIZED)
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locals = NULL; /* Let fast_2_locals handle it */
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else {
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locals = PyDict_New();
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if (locals == NULL) {
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Py_DECREF(f);
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return NULL;
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}
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}
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}
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else {
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if (locals == NULL)
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locals = globals;
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Py_INCREF(locals);
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}
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f->f_locals = locals;
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f->f_trace = NULL;
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f->f_exc_type = f->f_exc_value = f->f_exc_traceback = NULL;
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f->f_tstate = tstate;
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f->f_lasti = 0;
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f->f_lineno = code->co_firstlineno;
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f->f_restricted = (builtins != tstate->interp->builtins);
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f->f_iblock = 0;
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f->f_nlocals = code->co_nlocals;
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f->f_stacksize = extras - code->co_nlocals;
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while (--extras >= 0)
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f->f_localsplus[extras] = NULL;
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f->f_valuestack = f->f_localsplus + f->f_nlocals;
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return f;
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}
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/* Block management */
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void
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PyFrame_BlockSetup(PyFrameObject *f, int type, int handler, int level)
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{
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PyTryBlock *b;
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if (f->f_iblock >= CO_MAXBLOCKS)
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Py_FatalError("XXX block stack overflow");
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b = &f->f_blockstack[f->f_iblock++];
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b->b_type = type;
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b->b_level = level;
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b->b_handler = handler;
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}
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PyTryBlock *
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PyFrame_BlockPop(PyFrameObject *f)
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{
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PyTryBlock *b;
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if (f->f_iblock <= 0)
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Py_FatalError("XXX block stack underflow");
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b = &f->f_blockstack[--f->f_iblock];
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return b;
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}
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/* Convert between "fast" version of locals and dictionary version */
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void
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PyFrame_FastToLocals(PyFrameObject *f)
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{
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/* Merge fast locals into f->f_locals */
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PyObject *locals, *map;
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PyObject **fast;
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PyObject *error_type, *error_value, *error_traceback;
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int j;
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if (f == NULL)
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return;
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locals = f->f_locals;
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if (locals == NULL) {
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locals = f->f_locals = PyDict_New();
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if (locals == NULL) {
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PyErr_Clear(); /* Can't report it :-( */
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return;
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}
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}
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if (f->f_nlocals == 0)
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return;
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map = f->f_code->co_varnames;
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if (!PyDict_Check(locals) || !PyTuple_Check(map))
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return;
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PyErr_Fetch(&error_type, &error_value, &error_traceback);
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fast = f->f_localsplus;
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j = PyTuple_Size(map);
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if (j > f->f_nlocals)
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j = f->f_nlocals;
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for (; --j >= 0; ) {
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PyObject *key = PyTuple_GetItem(map, j);
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PyObject *value = fast[j];
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if (value == NULL) {
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PyErr_Clear();
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if (PyDict_DelItem(locals, key) != 0)
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PyErr_Clear();
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}
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else {
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if (PyDict_SetItem(locals, key, value) != 0)
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PyErr_Clear();
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}
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}
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PyErr_Restore(error_type, error_value, error_traceback);
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}
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void
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PyFrame_LocalsToFast(PyFrameObject *f, int clear)
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{
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/* Merge f->f_locals into fast locals */
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PyObject *locals, *map;
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PyObject **fast;
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PyObject *error_type, *error_value, *error_traceback;
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int j;
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if (f == NULL)
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return;
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locals = f->f_locals;
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map = f->f_code->co_varnames;
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if (locals == NULL || f->f_code->co_nlocals == 0)
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return;
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if (!PyDict_Check(locals) || !PyTuple_Check(map))
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return;
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PyErr_Fetch(&error_type, &error_value, &error_traceback);
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fast = f->f_localsplus;
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j = PyTuple_Size(map);
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if (j > f->f_nlocals)
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j = f->f_nlocals;
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for (; --j >= 0; ) {
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PyObject *key = PyTuple_GetItem(map, j);
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PyObject *value = PyDict_GetItem(locals, key);
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Py_XINCREF(value);
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if (value != NULL || clear) {
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Py_XDECREF(fast[j]);
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fast[j] = value;
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}
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}
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PyErr_Restore(error_type, error_value, error_traceback);
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}
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/* Clear out the free list */
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void
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PyFrame_Fini(void)
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{
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while (free_list != NULL) {
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PyFrameObject *f = free_list;
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free_list = free_list->f_back;
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PyObject_DEL(f);
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}
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}
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