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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)2019 Jython Developers.
// Licensed to PSF under a Contributor Agreement.
package org.python.core;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Set;
import org.python.util.Generic;
public class PyReflectedFunction extends PyObject implements Traverseproc {
public String __name__;
public PyObject __doc__ = Py.None;
public PyObject __module__ = Py.None;
public ReflectedArgs[] argslist = new ReflectedArgs[1];
public int nargs;
/** Whether __call__ should act as if this is called as a static method. */
private boolean calledStatically;
protected PyReflectedFunction(String name) {
__name__ = name;
}
public PyReflectedFunction(Method... methods) {
this(methods[0].getName());
for (Method meth : methods) {
addMethod(meth);
}
if (nargs == 0) {
String msg = String.format("Attempted to make Java method visible, but it isn't "
+ "callable[method=%s, class=%s]",
methods[0].getName(),
methods[0].getDeclaringClass());
throw Py.SystemError(msg);
}
}
@Override
public PyObject _doget(PyObject container) {
return _doget(container, null);
}
@Override
public PyObject _doget(PyObject container, PyObject wherefound) {
// NOTE: this calledStatically business is pretty hacky
if (container == null) {
return calledStatically ? this : copyWithCalledStatically(true);
}
return new PyMethod(calledStatically ? copyWithCalledStatically(false) : this,
container, wherefound);
}
private ReflectedArgs makeArgs(Method m) {
return new ReflectedArgs(m,
m.getParameterTypes(),
m.getDeclaringClass(),
Modifier.isStatic(m.getModifiers()),
m.isVarArgs());
}
public PyReflectedFunction copy() {
PyReflectedFunction func = new PyReflectedFunction(__name__);
func.__doc__ = __doc__;
func.__module__ = __module__;
func.nargs = nargs;
func.argslist = new ReflectedArgs[nargs];
System.arraycopy(argslist, 0, func.argslist, 0, nargs);
return func;
}
private PyReflectedFunction copyWithCalledStatically(boolean calledStatically) {
PyReflectedFunction copy = copy();
copy.calledStatically = calledStatically;
return copy;
}
public boolean handles(Method method) {
return handles(makeArgs(method));
}
protected boolean handles(ReflectedArgs args) {
for (int i = 0; i < nargs; i++) {
int cmp = args.compareTo(argslist[i]);
if (cmp == 0) {
return true;
} else if (cmp == 1) {
return false;
}
}
return false;
}
public void addMethod(Method m) {
// Only add public methods unless we're overriding
if (!Modifier.isPublic(m.getModifiers()) && Options.respectJavaAccessibility) {
return;
}
if (isPackagedProtected(m.getDeclaringClass())) {
/*
* Set public methods on package protected classes accessible so that reflected calls to
* the method in subclasses of the package protected class will succeed. Yes, it's
* convoluted.
*
* This fails when done through reflection due to Sun JVM bug
* 4071957(http://tinyurl.com/le9vo). 4533479 actually describes the problem we're
* seeing, but there are a bevy of reflection bugs that stem from 4071957. Supposedly
* it'll be fixed in Dolphin but it's been promised in every version since Tiger
* so don't hold your breath.
*/
try {
m.setAccessible(true);
} catch (SecurityException se) {
// This case is pretty far in the corner, so don't scream if we can't set the method
// accessible due to a security manager. Any calls to it will fail with an
// IllegalAccessException, so it'll become visible there. This way we don't spam
// people who aren't calling methods like this from Python with warnings if a
// library they're using happens to have a method like this.
}
}
addArgs(makeArgs(m));
}
public static boolean isPackagedProtected(Class c) {
int mods = c.getModifiers();
return !(Modifier.isPublic(mods) || Modifier.isPrivate(mods) || Modifier.isProtected(mods));
}
protected void addArgs(ReflectedArgs args) {
int i;
for (i = 0; i < nargs; i++) {
int cmp = args.compareTo(argslist[i]);
if (cmp == 0) {
return;
} else if (cmp == ReflectedArgs.REPLACE) {
argslist[i] = args;
return;
} else if (cmp == -1) {
break;
}
}
int nn = nargs + 1;
if (nn > argslist.length) {
ReflectedArgs[] newargslist = new ReflectedArgs[nn + 2];
System.arraycopy(argslist, 0, newargslist, 0, nargs);
argslist = newargslist;
}
for (int j = nargs; j > i; j--) {
argslist[j] = argslist[j - 1];
}
argslist[i] = args;
nargs = nn;
}
@Override
public PyObject __call__(PyObject self, PyObject[] args, String[] keywords) {
ReflectedCallData callData = new ReflectedCallData();
ReflectedArgs match = null;
// varargs methods should always have lower precedence than a non-varargs
// method that also applies but as they will always have <= arguments than an
// alternative non-vararg method, they will appear first in the list of options.
// Keep track of the first vararg method but don't use it unless no other
// method matches.
ReflectedArgs varargMatch = null;
ReflectedCallData varargData = null;
for (int i = 0; i < nargs && match == null; i++) {
if (argslist[i].matches(self, args, keywords, callData)) {
if (!argslist[i].isVarArgs) {
match = argslist[i];
} else {
varargMatch = argslist[i];
varargData = callData;
callData = new ReflectedCallData();
}
}
}
if (match == null) {
if (varargMatch == null) {
throwError(callData.errArg, args.length, self != null, keywords.length != 0);
}
match = varargMatch;
callData = varargData;
}
Object cself = callData.self;
Method m = (Method)match.method;
// If this is a direct call to a Java class instance method with a PyProxy instance as the
// arg, use the super__ version to actually route this through the method on the class.
if (self == null && cself != null && cself instanceof PyProxy
&& !__name__.startsWith("super__")
&& match.declaringClass != cself.getClass()) {
String mname = ("super__" + __name__);
try {
m = cself.getClass().getMethod(mname, m.getParameterTypes());
} catch (Exception e) {
throw Py.JavaError(e);
}
}
Object o;
try {
o = m.invoke(cself, callData.getArgsArray());
} catch (Throwable t) {
throw Py.JavaError(t);
}
return Py.java2py(o);
}
@Override
public PyObject __call__(PyObject[] args, String[] keywords) {
PyObject self;
if (calledStatically) {
self = null;
} else {
PyObject[] unboundArgs = new PyObject[args.length - 1];
System.arraycopy(args, 1, unboundArgs, 0, unboundArgs.length);
self = args[0];
args = unboundArgs;
}
return __call__(self, args, keywords);
}
// A bunch of code to make error handling prettier
protected void throwError(String message) {
throw Py.TypeError(__name__ + "(): " + message);
}
private static void addRange(StringBuilder buf, int min, int max, String sep) {
if (buf.length() > 0) {
buf.append(sep);
}
if (min < max) {
buf.append(Integer.toString(min)).append('-').append(max);
} else {
buf.append(min);
}
}
protected void throwArgCountError(int nArgs, boolean self) {
// Assume no argument lengths greater than 40...
boolean[] legalArgs = new boolean[40];
int maxArgs = -1;
int minArgs = 40;
for (int i = 0; i < nargs; i++) {
ReflectedArgs rargs = argslist[i];
int l = rargs.args.length;
if (!self && !rargs.isStatic) {
l += 1;
}
legalArgs[l] = true;
if (l > maxArgs) {
maxArgs = l;
}
if (l < minArgs) {
minArgs = l;
}
}
StringBuilder buf = new StringBuilder();
int startRange = minArgs;
int a = minArgs + 1;
while (a < maxArgs) {
if (legalArgs[a]) {
a++;
continue;
} else {
addRange(buf, startRange, a - 1, ", ");
a++;
while (a <= maxArgs) {
if (legalArgs[a]) {
startRange = a;
break;
}
a++;
}
}
}
addRange(buf, startRange, maxArgs, " or ");
throwError("expected " + buf + " args; got " + nArgs);
}
private static String ordinal(int n) {
switch(n + 1){
case 0:
return "self";
case 1:
return "1st";
case 2:
return "2nd";
case 3:
return "3rd";
default:
return Integer.toString(n + 1) + "th";
}
}
private static String niceName(Class arg) {
if (arg == String.class || arg == PyString.class) {
return "String";
}
if (arg.isArray()) {
return niceName(arg.getComponentType()) + "[]";
}
return arg.getName();
}
protected void throwBadArgError(int errArg, int nArgs, boolean self) {
Set> argTypes = Generic.set();
for (int i = 0; i < nargs; i++) {
// This check works almost all the time.
// I'm still a little worried about non-static methods called with an explicit self...
if (argslist[i].args.length == nArgs ||
(!argslist[i].isStatic && !self && argslist[i].args.length == nArgs - 1)) {
if (errArg == ReflectedCallData.UNABLE_TO_CONVERT_SELF) {
argTypes.add(argslist[i].declaringClass);
} else {
argTypes.add(argslist[i].args[errArg]);
}
}
}
StringBuilder buf = new StringBuilder();
for (Class arg : argTypes) {
buf.append(niceName(arg));
buf.append(", ");
}
if (buf.length() > 2) {
buf.setLength(buf.length() - 2);
}
throwError(ordinal(errArg) + " arg can't be coerced to " + buf);
}
protected void throwError(int errArg, int nArgs, boolean self, boolean keywords) {
if (keywords) {
throwError("takes no keyword arguments");
} else if (errArg == ReflectedCallData.BAD_ARG_COUNT) {
throwArgCountError(nArgs, self);
} else {
throwBadArgError(errArg, nArgs, self);
}
}
// Included only for debugging purposes...
public void printArgs() {
System.err.println("nargs: " + nargs);
for (int i = 0; i < nargs; i++) {
ReflectedArgs args = argslist[i];
System.err.println(args.toString());
}
}
@Override
public String toString() {
return "";
}
/* Traverseproc implementation */
@Override
public int traverse(Visitproc visit, Object arg) {
if (__module__ != null) {
int res = visit.visit(__module__, arg);
if (res != 0) {
return res;
}
}
return __doc__ != null ? visit.visit(__doc__, arg) : 0;
}
@Override
public boolean refersDirectlyTo(PyObject ob) {
return ob != null && (ob == __doc__ || ob == __module__);
}
}