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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.Member;
/** Map the signature of a method to the {@code Method} itself, within the context of a given simple name. This is used in support of signature polymorphism in Java methods and constructors reflected into Python. **/
public class ReflectedArgs {
/** The types of arguments defining this signature (key) */
public Class[] args;
/** The specific method (or constructor). */
public Member method;
public Class declaringClass;
public boolean isStatic;
public boolean isVarArgs;
public int flags;
public static final int StandardCall = 0;
public static final int PyArgsCall = 1;
public static final int PyArgsKeywordsCall = 2;
public ReflectedArgs(Member method, Class[] args, Class declaringClass, boolean isStatic) {
this(method, args, declaringClass, isStatic, false);
}
public ReflectedArgs(Member method, Class[] args, Class declaringClass, boolean isStatic,
boolean isVarArgs) {
this.method = method;
this.args = args;
this.declaringClass = declaringClass;
this.isStatic = isStatic;
// only used for varargs matching; it should be added after the unboxed form
this.isVarArgs = isVarArgs;
if (args.length == 1 && args[0] == PyObject[].class) {
this.flags = PyArgsCall;
} else if (args.length == 2 && args[0] == PyObject[].class && args[1] == String[].class) {
this.flags = PyArgsKeywordsCall;
} else {
this.flags = StandardCall;
}
}
public boolean matches(PyObject self, PyObject[] pyArgs, String[] keywords,
ReflectedCallData callData) {
if (this.flags != PyArgsKeywordsCall) {
if (keywords != null && keywords.length != 0) {
return false;
}
}
// if (isStatic ? self != null : self == null) return Py.NoConversion;
/* Ugly code to handle mismatch in static vs. instance functions... */
/*
* Will be very inefficient in cases where static and instance functions both exist with
* same names and number of args
*/
if (this.isStatic) {
if (self != null) {
self = null;
}
} else {
if (self == null) {
if (pyArgs.length == 0) {
return false;
}
self = pyArgs[0];
PyObject[] newArgs = new PyObject[pyArgs.length - 1];
System.arraycopy(pyArgs, 1, newArgs, 0, newArgs.length);
pyArgs = newArgs;
}
}
if (this.flags == PyArgsKeywordsCall) { // foo(PyObject[], String[])
callData.setLength(2);
callData.args[0] = pyArgs;
callData.args[1] = keywords;
callData.self = self;
if (self != null) {
Object tmp = self.__tojava__(this.declaringClass);
if (tmp != Py.NoConversion) {
callData.self = tmp;
}
}
return true;
} else if (this.flags == PyArgsCall) { // foo(PyObject[])
callData.setLength(1);
callData.args[0] = pyArgs;
callData.self = self;
if (self != null) {
Object tmp = self.__tojava__(this.declaringClass);
if (tmp != Py.NoConversion) {
callData.self = tmp;
}
}
return true;
}
int n = this.args.length;
// if we have a varargs method AND the last PyObject is not a list/tuple
// we need to do box (wrap with an array) the last pyArgs.length - n args
// (which might be empty)
//
// examples:
// test(String... x)
// test(List... x)
//
// in this last example, don't worry if someone is overly clever in calling this,
// they can always write their own version of PyReflectedFunction and put it in the proxy
// if that's what they need to do ;)
if (isVarArgs) {
pyArgs = ensureBoxedVarargs(pyArgs, n);
}
if (pyArgs.length != n) {
return false;
}
// Make error messages clearer
callData.errArg = ReflectedCallData.UNABLE_TO_CONVERT_SELF;
if (self != null) {
Object tmp = self.__tojava__(this.declaringClass);
if (tmp == Py.NoConversion) {
return false;
}
callData.self = tmp;
} else {
callData.self = null;
}
callData.setLength(n);
Object[] javaArgs = callData.args;
for (int i = 0; i < n; i++) {
PyObject pyArg = pyArgs[i];
Class targetClass = this.args[i];
Object javaArg = pyArg.__tojava__(targetClass);
javaArgs[i] = javaArg;
if (javaArg == Py.NoConversion) {
if (i > callData.errArg) {
callData.errArg = i;
}
return false;
}
}
return true;
}
/* Boxes argument in the varargs position if not already boxed */
private PyObject[] ensureBoxedVarargs(PyObject[] pyArgs, int n) {
if (pyArgs.length == 0) {
// If there are no args return an empty list
return new PyObject[] {new PyList()};
}
PyObject lastArg = pyArgs[pyArgs.length - 1];
if (pyArgs.length == n && (lastArg instanceof PySequenceList || lastArg instanceof PyArray
|| lastArg instanceof PyXRange || lastArg instanceof PyIterator)) {
// NOTE that the check is against PySequenceList, not PySequence,
// because certain Java <=> Python semantics currently require this
// additional strictness. Perhaps this can be relaxed.
// Empirically this list is exhaustive against the Jython runtime,
// excluding only PyBaseString, PyMemoryView, Py2kBuffer, BaseBytes,
// and AstList, many/most of which seem likely to be problematic for
// varargs usage.
// This is only relevant if the number of arguments would be correct if a final sequence
// argument was treated as a vararg argument. eg, if two lists are passed to a function
// that accepts (Object...), they should be boxed and passed as a single list, even though
// the final arg is a sequence.
// FIXME also check if lastArg is sequence-like
return pyArgs; // will be boxed in an array once __tojava__ is called
}
int non_varargs_len = n - 1;
if (pyArgs.length < non_varargs_len) {
return pyArgs;
}
PyObject[] boxedPyArgs = new PyObject[n];
for (int i = 0; i < non_varargs_len; i++) {
boxedPyArgs[i] = pyArgs[i];
}
int varargs_len = pyArgs.length - non_varargs_len;
PyObject[] varargs = new PyObject[varargs_len];
for (int i = 0; i < varargs_len; i++) {
varargs[i] = pyArgs[non_varargs_len + i];
}
boxedPyArgs[non_varargs_len] = new PyList(varargs);
return boxedPyArgs;
}
public static int precedence(Class arg) {
if (arg == Object.class) {
return 3000;
}
if (arg.isPrimitive()) {
if (arg == Long.TYPE) {
return 10;
}
if (arg == Integer.TYPE) {
return 11;
}
if (arg == Short.TYPE) {
return 12;
}
if (arg == Character.TYPE) {
return 13;
}
if (arg == Byte.TYPE) {
return 14;
}
if (arg == Double.TYPE) {
return 20;
}
if (arg == Float.TYPE) {
return 21;
}
if (arg == Boolean.TYPE) {
return 30;
}
}
// Consider Strings a primitive type
// This makes them higher priority than byte[]
if (arg == String.class) {
return 40;
}
if (arg.isArray()) {
Class componentType = arg.getComponentType();
if (componentType == Object.class) {
return 2500;
}
return 100 + precedence(componentType);
}
return 2000;
}
/*
* Returns 0 iff arg1 == arg2 Returns +/-1 iff arg1 and arg2 are unimportantly different Returns
* +/-2 iff arg1 and arg2 are significantly different
*/
public static int compare(Class arg1, Class arg2) {
int p1 = precedence(arg1);
int p2 = precedence(arg2);
// Special code if they are both nonprimitives
// Superclasses/superinterfaces are considered greater than sub's
if (p1 >= 2000 && p2 >= 2000) {
if (arg1.isAssignableFrom(arg2)) {
if (arg2.isAssignableFrom(arg1)) {
return 0;
} else {
return +2;
}
} else {
if (arg2.isAssignableFrom(arg1)) {
return -2;
} else {
int cmp = arg1.getName().compareTo(arg2.getName());
return cmp > 0 ? +1 : -1;
}
}
}
return p1 > p2 ? +2 : (p1 == p2 ? 0 : -2);
}
public static final int REPLACE = 1998;
public int compareTo(ReflectedArgs other) {
Class[] oargs = other.args;
// First decision based on flags
if (other.flags != this.flags) {
return other.flags < this.flags ? -1 : +1;
}
// Decision based on number of args
int n = this.args.length;
if (n < oargs.length) {
return -1;
}
if (n > oargs.length) {
return +1;
}
// Decide based on static/non-static
if (this.isStatic && !other.isStatic) {
return +1;
}
if (!this.isStatic && other.isStatic) {
return -1;
}
// Compare the arg lists
int cmp = 0;
for (int i = 0; i < n; i++) {
int tmp = compare(this.args[i], oargs[i]);
if (tmp == +2 || tmp == -2) {
cmp = tmp;
}
if (cmp == 0) {
cmp = tmp;
}
}
if (cmp != 0) {
return cmp > 0 ? +1 : -1;
}
// If arg lists are equivalent, look at declaring classes
boolean replace = other.declaringClass.isAssignableFrom(this.declaringClass);
// For static methods, use the child's version
// For instance methods, use the parent's version
if (!this.isStatic) {
replace = !replace;
}
return replace ? REPLACE : 0;
}
@Override
public String toString() {
String s = declaringClass + ", static=" + isStatic + ", varargs=" + isVarArgs + ",flags="
+ flags + ", " + method + "\n";
s = s + "\t(";
for (Class arg : args) {
s += arg.getName() + ", ";
}
s += ")";
return s;
}
}