// ==========================================================================

// This software is subject to the provisions of the Zope Public License,

// Version 2.0 (ZPL). A copy of the ZPL should accompany this distribution.

// THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED

// WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

// WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS

// FOR A PARTICULAR PURPOSE.

// ==========================================================================

using System;

using System.Collections;

using System.Reflection;

namespace Python.Runtime {

//========================================================================

// A MethodBinder encapsulates information about a (possibly overloaded)

// managed method, and is responsible for selecting the right method given

// a set of Python arguments. This is also used as a base class for the

// ConstructorBinder, a minor variation used to invoke constructors.

//========================================================================

internal class MethodBinder {

public ArrayList list;

public MethodBase[] methods;

public bool init = false;

internal MethodBinder () {

this.list = new ArrayList();

}

internal MethodBinder(MethodInfo mi) : base () {

this.list = new ArrayList();

this.list.Add(mi);

}

public int Count {

get { return this.list.Count; }

}

internal void AddMethod(MethodBase m) {

this.list.Add(m);

}

//====================================================================

// Return the array of MethodInfo for this method. The result array

// is arranged in order of precendence (done lazily to avoid doing it

// at all for methods that are never called).

//====================================================================

internal MethodBase[] GetMethods() {

if (!init) {

// I'm sure this could be made more efficient.

list.Sort(new MethodSorter());

methods = (MethodBase[])list.ToArray(typeof(MethodBase));

init = true;

}

return methods;

}

//====================================================================

// Precedence algorithm largely lifted from jython - the concerns are

// generally the same so we'll start w/this and tweak as necessary.

//====================================================================

internal static int GetPrecedence(MethodBase mi) {

ParameterInfo[] pi = mi.GetParameters();

int val = mi.IsStatic ? 3000 : 0;

int num = pi.Length;

for (int i = 0; i < num; i++) {

val += ArgPrecedence(pi[i].ParameterType);

}

return val;

}

//====================================================================

// Return a precedence value for a particular Type object.

//====================================================================

internal static int ArgPrecedence(Type t) {

Type objectType = typeof(Object);

if (t == objectType) return 3000;

TypeCode tc = Type.GetTypeCode(t);

if (tc == TypeCode.Object) return 1;

if (tc == TypeCode.UInt64) return 10;

if (tc == TypeCode.UInt32) return 11;

if (tc == TypeCode.UInt16) return 12;

if (tc == TypeCode.Int64) return 13;

if (tc == TypeCode.Int32) return 14;

if (tc == TypeCode.Int16) return 15;

if (tc == TypeCode.Char) return 16;

if (tc == TypeCode.SByte) return 17;

if (tc == TypeCode.Byte) return 18;

if (tc == TypeCode.Single) return 20;

if (tc == TypeCode.Double) return 21;

if (tc == TypeCode.String) return 30;

if (tc == TypeCode.Boolean) return 40;

if (t.IsArray) {

Type e = t.GetElementType();

if (e == objectType)

return 2500;

return 100 + ArgPrecedence(e);

}

return 2000;

}

internal static MethodInfo MatchByTypeSig(MethodInfo[] msig,

IntPtr psig) {

IntPtr args = psig;

bool free = false;

if (!Runtime.PyTuple_Check(psig)) {

args = Runtime.PyTuple_New(1);

Runtime.Incref(psig);

Runtime.PyTuple_SetItem(args, 0, psig);

free = true;

}

int plen = Runtime.PyTuple_Size(args);

MethodInfo match = null;

// XXX: what about out args, etc.?

for (int i = 0; i < msig.Length; i++) {

ParameterInfo[] pi = msig[i].GetParameters();

if (pi.Length != plen) {

continue;

}

bool matched = true;

for (int n = 0; n < pi.Length; n++) {

IntPtr p = Runtime.PyTuple_GetItem(args, n);

if (p == IntPtr.Zero) {

Exceptions.Clear();

break;

}

ClassBase c = ManagedType.GetManagedObject(p) as ClassBase;

Type t = (c != null) ? c.type :

Converter.GetTypeByAlias(p);

if (t == null) {

break;

}

if (t != pi[n].ParameterType) {

matched = false;

break;

}

}

if (matched) {

match = msig[i];

break;

}

}

if (free) {

Runtime.Decref(args);

}

return match;

}

//====================================================================

// Bind the given Python instance and arguments to a particular method

// overload and return a structure that contains the converted Python

// instance, converted arguments and the correct method to call.

//====================================================================

internal Binding Bind(IntPtr inst, IntPtr args, IntPtr kw) {

return this.Bind(inst, args, kw, null);

}

internal Binding Bind(IntPtr inst, IntPtr args, IntPtr kw,

MethodBase info) {

// loop to find match, return invoker w/ or /wo error

MethodBase[] _methods = null;

int nargs = Runtime.PyTuple_Size(args);

object arg;

if (info != null) {

_methods = (MethodBase[])Array.CreateInstance(

typeof(MethodBase), 1

);

_methods.SetValue(info, 0);

}

else {

_methods = GetMethods();

}

for (int i = 0; i < _methods.Length; i++) {

MethodBase mi = _methods[i];

ParameterInfo[] pi = mi.GetParameters();

int count = pi.Length;

int outs = 0;

if ( nargs == count ) {

Object[] margs = new Object[count];

for (int n = 0; n < count; n++) {

IntPtr op = Runtime.PyTuple_GetItem(args, n);

Type type = pi[n].ParameterType;

if (pi[n].IsOut || type.IsByRef) {

outs++;

}

if (!Converter.ToManaged(op, type, out arg, false)) {

Exceptions.Clear();

margs = null;

break;

}

margs[n] = arg;

}

if (margs == null) {

continue;

}

Object target = null;

if ((!mi.IsStatic) && (inst != IntPtr.Zero)) {

CLRObject co = (CLRObject)ManagedType.GetManagedObject(

inst

);

target = co.inst;

}

return new Binding(mi, target, margs, outs);

}

}

return null;

}

internal virtual IntPtr Invoke(IntPtr inst, IntPtr args, IntPtr kw) {

return this.Invoke(inst, args, kw, null);

}

internal virtual IntPtr Invoke(IntPtr inst, IntPtr args, IntPtr kw,

MethodBase info) {

Binding binding = this.Bind(inst, args, kw, info);

Object result;

if (binding == null) {

Exceptions.SetError(Exceptions.TypeError,

"no method matches given arguments"

);

return IntPtr.Zero;

}

IntPtr ts = PythonEngine.BeginAllowThreads();

try {

result = binding.info.Invoke(binding.inst,

BindingFlags.Default,

null,

binding.args,

null);

}

catch (Exception e) {

if (e.InnerException != null) {

e = e.InnerException;

}

PythonEngine.EndAllowThreads(ts);

Exceptions.SetError(e);

return IntPtr.Zero;

}

PythonEngine.EndAllowThreads(ts);

// If there are out parameters, we return a tuple containing

// the result followed by the out parameters. If there is only

// one out parameter and the return type of the method is void,

// we return the out parameter as the result to Python (for

// code compatibility with ironpython).

MethodInfo mi = (MethodInfo)binding.info;

if ((binding.outs == 1) && (mi.ReturnType == typeof(void))) {

}

if (binding.outs > 0) {

ParameterInfo[] pi = mi.GetParameters();

int c = pi.Length;

int n = 0;

IntPtr t = Runtime.PyTuple_New(binding.outs + 1);

IntPtr v = Converter.ToPython(result, mi.ReturnType);

Runtime.PyTuple_SetItem(t, n, v);

n++;

for (int i=0; i < c; i++) {

Type pt = pi[i].ParameterType;

if (pi[i].IsOut || pt.IsByRef) {

v = Converter.ToPython(binding.args[i], pt);

Runtime.PyTuple_SetItem(t, n, v);

n++;

}

}

if ((binding.outs == 1) && (mi.ReturnType == typeof(void))) {

v = Runtime.PyTuple_GetItem(t, 1);

Runtime.Incref(v);

Runtime.Decref(t);

return v;

}

return t;

}

return Converter.ToPython(result, mi.ReturnType);

}

}

//========================================================================

// Utility class to sort method info by parameter type precedence.

//========================================================================

internal class MethodSorter : IComparer {

int IComparer.Compare(Object m1, Object m2) {

int p1 = MethodBinder.GetPrecedence((MethodBase)m1);

int p2 = MethodBinder.GetPrecedence((MethodBase)m2);

if (p1 < p2) return -1;

if (p1 > p2) return 1;

return 0;

}

}

//========================================================================

// A Binding is a utility instance that bundles together a MethodInfo

// representing a method to call, a (possibly null) target instance for

// the call, and the arguments for the call (all as managed values).

//========================================================================

internal class Binding {

public MethodBase info;

public Object[] args;

public Object inst;

public int outs;

internal Binding(MethodBase info, Object inst, Object[] args,

int outs) {

this.info = info;

this.inst = inst;

this.args = args;

this.outs = outs;

}

}

}