Repository navigation
Expand file tree
/
Copy pathdelegatemanager.cs
More file actions
283 lines (241 loc) · 9.64 KB
/
Copy pathdelegatemanager.cs
File metadata and controls
283 lines (241 loc) · 9.64 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
using System;
using System.Collections;
using System.Reflection;
using System.Reflection.Emit;
namespace Python.Runtime
{
/// <summary>
/// The DelegateManager class manages the creation of true managed
/// delegate instances that dispatch calls to Python methods.
/// </summary>
internal class DelegateManager
{
private Hashtable cache;
private Type basetype;
private Type listtype;
private Type voidtype;
private Type typetype;
private Type ptrtype;
private CodeGenerator codeGenerator;
public DelegateManager()
{
basetype = typeof(Dispatcher);
listtype = typeof(ArrayList);
voidtype = typeof(void);
typetype = typeof(Type);
ptrtype = typeof(IntPtr);
cache = new Hashtable();
codeGenerator = new CodeGenerator();
}
/// <summary>
/// Given a true delegate instance, return the PyObject handle of the
/// Python object implementing the delegate (or IntPtr.Zero if the
/// delegate is not implemented in Python code.
/// </summary>
public IntPtr GetPythonHandle(Delegate d)
{
if (d?.Target is Dispatcher)
{
var disp = (Dispatcher)d.Target;
return disp.target;
}
return IntPtr.Zero;
}
/// <summary>
/// GetDispatcher is responsible for creating a class that provides
/// an appropriate managed callback method for a given delegate type.
/// </summary>
private Type GetDispatcher(Type dtype)
{
// If a dispatcher type for the given delegate type has already
// been generated, get it from the cache. The cache maps delegate
// types to generated dispatcher types. A possible optimization
// for the future would be to generate dispatcher types based on
// unique signatures rather than delegate types, since multiple
// delegate types with the same sig could use the same dispatcher.
object item = cache[dtype];
if (item != null)
{
return (Type)item;
}
string name = $"__{dtype.FullName}Dispatcher";
name = name.Replace('.', '_');
name = name.Replace('+', '_');
TypeBuilder tb = codeGenerator.DefineType(name, basetype);
// Generate a constructor for the generated type that calls the
// appropriate constructor of the Dispatcher base type.
MethodAttributes ma = MethodAttributes.Public |
MethodAttributes.HideBySig |
MethodAttributes.SpecialName |
MethodAttributes.RTSpecialName;
var cc = CallingConventions.Standard;
Type[] args = { ptrtype, typetype };
ConstructorBuilder cb = tb.DefineConstructor(ma, cc, args);
ConstructorInfo ci = basetype.GetConstructor(args);
ILGenerator il = cb.GetILGenerator();
il.Emit(OpCodes.Ldarg_0);
il.Emit(OpCodes.Ldarg_1);
il.Emit(OpCodes.Ldarg_2);
il.Emit(OpCodes.Call, ci);
il.Emit(OpCodes.Ret);
// Method generation: we generate a method named "Invoke" on the
// dispatcher type, whose signature matches the delegate type for
// which it is generated. The method body simply packages the
// arguments and hands them to the Dispatch() method, which deals
// with converting the arguments, calling the Python method and
// converting the result of the call.
MethodInfo method = dtype.GetMethod("Invoke");
ParameterInfo[] pi = method.GetParameters();
var signature = new Type[pi.Length];
for (var i = 0; i < pi.Length; i++)
{
signature[i] = pi[i].ParameterType;
}
MethodBuilder mb = tb.DefineMethod("Invoke", MethodAttributes.Public, method.ReturnType, signature);
ConstructorInfo ctor = listtype.GetConstructor(Type.EmptyTypes);
MethodInfo dispatch = basetype.GetMethod("Dispatch");
MethodInfo add = listtype.GetMethod("Add");
il = mb.GetILGenerator();
il.DeclareLocal(listtype);
il.Emit(OpCodes.Newobj, ctor);
il.Emit(OpCodes.Stloc_0);
for (var c = 0; c < signature.Length; c++)
{
Type t = signature[c];
il.Emit(OpCodes.Ldloc_0);
il.Emit(OpCodes.Ldarg_S, (byte)(c + 1));
if (t.IsValueType)
{
il.Emit(OpCodes.Box, t);
}
il.Emit(OpCodes.Callvirt, add);
il.Emit(OpCodes.Pop);
}
il.Emit(OpCodes.Ldarg_0);
il.Emit(OpCodes.Ldloc_0);
il.Emit(OpCodes.Call, dispatch);
if (method.ReturnType == voidtype)
{
il.Emit(OpCodes.Pop);
}
else if (method.ReturnType.IsValueType)
{
il.Emit(OpCodes.Unbox_Any, method.ReturnType);
}
il.Emit(OpCodes.Ret);
Type disp = tb.CreateType();
cache[dtype] = disp;
return disp;
}
/// <summary>
/// Given a delegate type and a callable Python object, GetDelegate
/// returns an instance of the delegate type. The delegate instance
/// returned will dispatch calls to the given Python object.
/// </summary>
internal Delegate GetDelegate(Type dtype, IntPtr callable)
{
Type dispatcher = GetDispatcher(dtype);
object[] args = { callable, dtype };
object o = Activator.CreateInstance(dispatcher, args);
return Delegate.CreateDelegate(dtype, o, "Invoke");
}
}
/* When a delegate instance is created that has a Python implementation,
the delegate manager generates a custom subclass of Dispatcher and
instantiates it, passing the IntPtr of the Python callable.
The "real" delegate is created using CreateDelegate, passing the
instance of the generated type and the name of the (generated)
implementing method (Invoke).
The true delegate instance holds the only reference to the dispatcher
instance, which ensures that when the delegate dies, the finalizer
of the referenced instance will be able to decref the Python
callable.
A possible alternate strategy would be to create custom subclasses
of the required delegate type, storing the IntPtr in it directly.
This would be slightly cleaner, but I'm not sure if delegates are
too "special" for this to work. It would be more work, so for now
the 80/20 rule applies :) */
public class Dispatcher
{
public IntPtr target;
public Type dtype;
public Dispatcher(IntPtr target, Type dtype)
{
Runtime.XIncref(target);
this.target = target;
this.dtype = dtype;
}
~Dispatcher()
{
// We needs to disable Finalizers until it's valid implementation.
// Current implementation can produce low probability floating bugs.
return;
// Note: the managed GC thread can run and try to free one of
// these *after* the Python runtime has been finalized!
if (Runtime.Py_IsInitialized() > 0)
{
IntPtr gs = PythonEngine.AcquireLock();
Runtime.XDecref(target);
PythonEngine.ReleaseLock(gs);
}
}
public object Dispatch(ArrayList args)
{
IntPtr gs = PythonEngine.AcquireLock();
object ob = null;
try
{
ob = TrueDispatch(args);
}
catch (Exception e)
{
PythonEngine.ReleaseLock(gs);
throw e;
}
PythonEngine.ReleaseLock(gs);
return ob;
}
public object TrueDispatch(ArrayList args)
{
MethodInfo method = dtype.GetMethod("Invoke");
ParameterInfo[] pi = method.GetParameters();
IntPtr pyargs = Runtime.PyTuple_New(pi.Length);
Type rtype = method.ReturnType;
for (var i = 0; i < pi.Length; i++)
{
// Here we own the reference to the Python value, and we
// give the ownership to the arg tuple.
IntPtr arg = Converter.ToPython(args[i], pi[i].ParameterType);
Runtime.PyTuple_SetItem(pyargs, i, arg);
}
IntPtr op = Runtime.PyObject_Call(target, pyargs, IntPtr.Zero);
Runtime.XDecref(pyargs);
if (op == IntPtr.Zero)
{
var e = new PythonException();
throw e;
}
if (rtype == typeof(void))
{
return null;
}
object result = null;
if (!Converter.ToManaged(op, rtype, out result, false))
{
Runtime.XDecref(op);
throw new ConversionException($"could not convert Python result to {rtype}");
}
Runtime.XDecref(op);
return result;
}
}
public class ConversionException : Exception
{
public ConversionException()
{
}
public ConversionException(string msg) : base(msg)
{
}
}
}