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Jython is an implementation of the high-level, dynamic, object-oriented
language Python written in 100% Pure Java, and seamlessly integrated with
the Java platform. It thus allows you to run Python on any Java platform.
/*
* Copyright (c) Corporation for National Research Initiatives
* Copyright (c) Jython Developers
*/
package org.python.core;
import org.python.expose.ExposedDelete;
import org.python.expose.ExposedGet;
import org.python.expose.ExposedSet;
import org.python.expose.ExposedType;
/**
* A Python frame object.
*/
@ExposedType(name = "frame", isBaseType = false)
public class PyFrame extends PyObject implements Traverseproc {
public static final PyType TYPE = PyType.fromClass(PyFrame.class);
/** Previous frame or null. */
@ExposedGet
public PyFrame f_back;
/** The underyling code object. */
@ExposedGet
public PyBaseCode f_code;
/** builtin symbol table. */
@ExposedGet
public PyObject f_builtins;
/** Global symbol table. */
@ExposedGet
public PyObject f_globals;
/** Local symbol table. */
public PyObject f_locals;
/** Current line number. */
public int f_lineno;
public PyObject[] f_fastlocals;
/** Nested scopes: cell + free env. */
public PyCell[] f_env;
private int env_j = 0;
public int f_ncells;
public int f_nfreevars;
@ExposedGet
public int f_lasti;
public Object[] f_savedlocals;
private Object generatorInput = Py.None;
/** with context exits - used by generated bytecode */
public PyObject[] f_exits;
/** An interface to functions suitable for tracing, e.g. via sys.settrace(). */
public TraceFunction tracefunc;
private static final String NAME_ERROR_MSG = "name '%.200s' is not defined";
private static final String GLOBAL_NAME_ERROR_MSG = "global name '%.200s' is not defined";
private static final String UNBOUNDLOCAL_ERROR_MSG =
"local variable '%.200s' referenced before assignment";
public PyFrame(PyBaseCode code, PyObject locals, PyObject globals, PyObject builtins) {
super(TYPE);
f_code = code;
f_locals = locals;
f_globals = globals;
f_builtins = builtins;
// This needs work to be efficient with multiple interpreter states
if (locals == null && code != null) {
// ! f_fastlocals needed for arg passing too
if (code.co_flags.isFlagSet(CodeFlag.CO_OPTIMIZED) || code.nargs > 0) {
if (code.co_nlocals > 0) {
// internal: may change
f_fastlocals = new PyObject[code.co_nlocals - code.jy_npurecell];
}
} else {
f_locals = new PyStringMap();
}
}
if (code != null) { // reserve space for env
int env_sz = 0;
if (code.co_freevars != null) {
env_sz += (f_nfreevars = code.co_freevars.length);
}
if (code.co_cellvars != null) {
env_sz += (f_ncells = code.co_cellvars.length);
}
if (env_sz > 0) {
f_env = new PyCell[env_sz];
}
}
}
public PyFrame(PyBaseCode code, PyObject globals) {
this(code, null, globals, null);
}
/**
* Populate the frame with closure variables, but at most once.
*
* @param freevars a PyTuple value
*/
void setupEnv(PyTuple freevars) {
int ntotal = f_ncells + f_nfreevars;
// add space for the cellvars
for (; env_j < f_ncells; env_j++) {
f_env[env_j] = new PyCell();
}
// inherit the freevars
for (int i = 0; env_j < ntotal; i++, env_j++) {
f_env[env_j] = (PyCell)freevars.pyget(i);
}
}
void setGeneratorInput(Object value) {
generatorInput = value;
}
public Object getGeneratorInput() {
Object input = generatorInput;
generatorInput = Py.None;
return input;
}
public Object checkGeneratorInput() {
return generatorInput;
}
/**
* Return the locals dict. First merges the fast locals into
* f_locals, then returns the updated f_locals.
*
* @return a PyObject mapping of locals
*/
@ExposedGet(name = "f_locals")
public PyObject getLocals() {
if (f_locals == null) {
f_locals = new PyStringMap();
}
if (f_code != null && (f_code.co_nlocals > 0 || f_nfreevars > 0)) {
int i;
if (f_fastlocals != null) {
for (i = 0; i < f_fastlocals.length; i++) {
PyObject o = f_fastlocals[i];
if (o != null) f_locals.__setitem__(f_code.co_varnames[i], o);
}
if (!f_code.co_flags.isFlagSet(CodeFlag.CO_OPTIMIZED)) {
f_fastlocals = null;
}
}
int j = 0;
for (i = 0; i < f_ncells; i++, j++) {
PyObject v = f_env[j].ob_ref;
if (v != null) {
f_locals.__setitem__(f_code.co_cellvars[i], v);
}
}
for (i = 0; i < f_nfreevars; i++, j++) {
PyObject v = f_env[j].ob_ref;
if (v != null) {
f_locals.__setitem__(f_code.co_freevars[i], v);
}
}
}
return f_locals;
}
@ExposedGet(name = "f_trace")
public PyObject getTrace() {
return tracefunc instanceof PythonTraceFunction ?
((PythonTraceFunction)tracefunc).tracefunc : Py.None;
}
@ExposedSet(name = "f_trace")
public void setTrace(PyObject trace) {
tracefunc = new PythonTraceFunction(trace);
}
@ExposedDelete(name = "f_trace")
public void delTrace() {
tracefunc = null;
}
/**
* Return the current f_locals dict.
*
* @return a PyObject mapping of locals
*/
public PyObject getf_locals() {
// XXX: This could be deprecated, grab f_locals directly
// instead. only the compiler calls this
return f_locals;
}
/**
* Track the current line number. Called by generated code.
*
* This is not to be confused with the CPython method
* frame_setlineno() which causes the interpreter to jump to
* the given line.
*/
public void setline(int line) {
f_lineno = line;
if (tracefunc != null) {
tracefunc = tracefunc.traceLine(this, line);
}
}
@ExposedGet(name = "f_lineno")
public int getline() {
return tracefunc != null ? f_lineno : f_code.getline(this);
}
public PyObject getlocal(int index) {
if (f_fastlocals != null) {
PyObject ret = f_fastlocals[index];
if (ret != null) {
return ret;
}
}
String name = f_code.co_varnames[index];
if (f_locals != null) {
PyObject ret = f_locals.__finditem__(name);
if (ret != null) {
return ret;
}
}
throw Py.UnboundLocalError(String.format(UNBOUNDLOCAL_ERROR_MSG, name));
}
public PyObject getname(String index) {
PyObject ret;
if (f_locals == null || f_locals == f_globals) {
ret = doGetglobal(index);
} else {
ret = f_locals.__finditem__(index);
if (ret != null) {
return ret;
}
ret = doGetglobal(index);
}
if (ret != null) {
return ret;
}
throw Py.NameError(String.format(NAME_ERROR_MSG, index));
}
public PyObject getglobal(String index) {
PyObject ret = doGetglobal(index);
if (ret != null) {
return ret;
}
throw Py.NameError(String.format(GLOBAL_NAME_ERROR_MSG, index));
}
private PyObject doGetglobal(String index) {
PyObject ret = f_globals.__finditem__(index);
if (ret != null) {
return ret;
}
// Set up f_builtins if not already set
if (f_builtins == null) {
f_builtins = Py.getThreadState().getSystemState().builtins;
}
return f_builtins.__finditem__(index);
}
public void setlocal(int index, PyObject value) {
if (f_fastlocals != null) {
f_fastlocals[index] = value;
} else {
setlocal(f_code.co_varnames[index], value);
}
}
public void setlocal(String index, PyObject value) {
if (f_locals != null) {
f_locals.__setitem__(index, value);
} else {
throw Py.SystemError(String.format("no locals found when storing '%s'", value));
}
}
public void setglobal(String index, PyObject value) {
f_globals.__setitem__(index, value);
}
public void dellocal(int index) {
if (f_fastlocals != null) {
if (f_fastlocals[index] == null) {
throw Py.UnboundLocalError(String.format(UNBOUNDLOCAL_ERROR_MSG,
f_code.co_varnames[index]));
}
f_fastlocals[index] = null;
} else {
dellocal(f_code.co_varnames[index]);
}
}
public void dellocal(String index) {
if (f_locals != null) {
try {
f_locals.__delitem__(index);
} catch (PyException pye) {
if (pye.match(Py.KeyError)) {
throw Py.NameError(String.format(NAME_ERROR_MSG, index));
}
throw pye;
}
} else {
throw Py.SystemError(String.format("no locals when deleting '%s'", index));
}
}
public void delglobal(String index) {
try {
f_globals.__delitem__(index);
} catch (PyException pye) {
if (pye.match(Py.KeyError)) {
throw Py.NameError(String.format(GLOBAL_NAME_ERROR_MSG, index));
}
throw pye;
}
}
// nested scopes helpers
public PyObject getclosure(int index) {
return f_env[index];
}
public PyObject getderef(int index) {
PyObject obj = f_env[index].ob_ref;
if (obj != null) {
return obj;
}
String name;
if (index >= f_ncells) {
name = f_code.co_freevars[index - f_ncells];
} else {
name = f_code.co_cellvars[index];
}
throw Py.UnboundLocalError(String.format(UNBOUNDLOCAL_ERROR_MSG, name));
}
public void setderef(int index, PyObject value) {
f_env[index].ob_ref = value;
}
public void to_cell(int parm_index, int env_index) {
f_env[env_index].ob_ref = f_fastlocals[parm_index];
}
/* Traverseproc implementation */
@Override
public int traverse(Visitproc visit, Object arg) {
int retVal;
if (f_back != null) {
retVal = visit.visit(f_back, arg);
if (retVal != 0) {
return retVal;
}
}
if (f_code != null) {
retVal = visit.visit(f_code, arg);
if (retVal != 0) {
return retVal;
}
}
if (f_builtins != null) {
retVal = visit.visit(f_builtins, arg);
if (retVal != 0) {
return retVal;
}
}
if (f_globals != null) {
retVal = visit.visit(f_globals, arg);
if (retVal != 0) {
return retVal;
}
}
if (f_locals != null) {
retVal = visit.visit(f_locals, arg);
if (retVal != 0) {
return retVal;
}
}
if (tracefunc != null && tracefunc instanceof Traverseproc) {
retVal = ((Traverseproc) tracefunc).traverse(visit, arg);
if (retVal != 0) {
return retVal;
}
}
// CPython also features fields for an exception.
// These are not present in PyFrame in Jython:
// Py_VISIT(f->f_exc_type);
// Py_VISIT(f->f_exc_value);
// Py_VISIT(f->f_exc_traceback);
/* locals */
if (f_fastlocals != null) {
for (PyObject ob: f_fastlocals) {
if (ob != null) {
retVal = visit.visit(ob, arg);
if (retVal != 0) {
return retVal;
}
}
}
}
if (f_savedlocals != null) {
for (Object ob: f_savedlocals) {
if (ob != null) {
if (ob instanceof PyObject) {
retVal = visit.visit((PyObject) ob, arg);
if (retVal != 0) {
return retVal;
}
} else if (ob instanceof Traverseproc) {
retVal = ((Traverseproc) ob).traverse(visit, arg);
if (retVal != 0) {
return retVal;
}
}
}
}
}
/* Jython-only miscellaneous */
if (f_env != null) {
for (PyCell ob: f_env) {
if (ob != null) {
retVal = visit.visit(ob, arg);
if (retVal != 0) {
return retVal;
}
}
}
}
if (generatorInput != null) {
if (generatorInput instanceof PyObject) {
retVal = visit.visit((PyObject) generatorInput, arg);
if (retVal != 0) {
return retVal;
}
} else if (generatorInput instanceof Traverseproc) {
retVal = ((Traverseproc) generatorInput).traverse(visit, arg);
if (retVal != 0) {
return retVal;
}
}
}
if (f_exits != null) {
for (PyObject ob: f_exits) {
if (ob != null) {
retVal = visit.visit(ob, arg);
if (retVal != 0) {
return retVal;
}
}
}
}
// CPython also traverses the stack. This seems to be not necessary
// in Jython since there is no stack-equivalent in PyFrame:
//
// /* stack */
// if (f->f_stacktop != NULL) {
// for (p = f->f_valuestack; p < f->f_stacktop; p++)
// Py_VISIT(*p);
// }
return 0;
}
@Override
public boolean refersDirectlyTo(PyObject ob) throws UnsupportedOperationException {
if (ob == null) {
return false;
} else if (ob == f_back || ob == f_code || ob == f_builtins
|| ob == f_globals || ob == f_locals || ob == generatorInput) {
return true;
}
if (f_fastlocals != null) {
for (PyObject obj: f_fastlocals) {
if (obj == ob) {
return true;
}
}
}
if (f_env != null) {
for (PyObject obj: f_env) {
if (obj == ob) {
return true;
}
}
}
if (f_exits != null) {
for (PyObject obj: f_exits) {
if (obj == ob) {
return true;
}
}
}
if (f_savedlocals != null) {
for (Object obj: f_savedlocals) {
if (obj == ob) {
return true;
} else if (obj != null && obj instanceof Traverseproc
&&((Traverseproc) obj).refersDirectlyTo(ob)) {
return true;
}
}
}
if (tracefunc != null && tracefunc instanceof Traverseproc
&&((Traverseproc) tracefunc).refersDirectlyTo(ob)) {
return true;
}
return generatorInput instanceof Traverseproc ?
((Traverseproc) generatorInput).refersDirectlyTo(ob) : false;
}
}