using System;
using System.Collections;
using System.Collections.Generic;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Security;
using System.Linq;
namespace Python.Runtime
{
///
/// The ClassManager is responsible for creating and managing instances
/// that implement the Python type objects that reflect managed classes.
/// Each managed type reflected to Python is represented by an instance
/// of a concrete subclass of ClassBase. Each instance is associated with
/// a generated Python type object, whose slots point to static methods
/// of the managed instance's class.
///
internal class ClassManager
{
// Binding flags to determine which members to expose in Python.
// This is complicated because inheritance in Python is name
// based. We can't just find DeclaredOnly members, because we
// could have a base class A that defines two overloads of a
// method and a class B that defines two more. The name-based
// descriptor Python will find needs to know about inherited
// overloads as well as those declared on the sub class.
internal static readonly BindingFlags BindingFlags = BindingFlags.Static |
BindingFlags.Instance |
BindingFlags.Public |
BindingFlags.NonPublic;
private static Dictionary cache;
private static readonly Type dtype;
private ClassManager()
{
}
static ClassManager()
{
// SEE: https://msdn.microsoft.com/en-us/library/96b1ayy4(v=vs.100).aspx
// ""All delegates inherit from MulticastDelegate, which inherits from Delegate.""
// Was Delegate, which caused a null MethodInfo returned from GetMethode("Invoke")
// and crashed on Linux under Mono.
dtype = typeof(MulticastDelegate);
}
public static void Reset()
{
cache = new Dictionary(128);
}
internal static void DisposePythonWrappersForClrTypes()
{
var visited = new HashSet();
var visitedHandle = GCHandle.Alloc(visited);
var visitedPtr = (IntPtr)visitedHandle;
try
{
foreach (var cls in cache.Values)
{
// XXX: Force to release instance's managed resources
// but not dealloc itself immediately.
// These managed resources should preserve vacant shells
// since others may still referencing it.
cls.CallTypeTraverse(TraverseTypeClear, visitedPtr);
cls.CallTypeClear();
cls.DecrRefCount();
}
}
finally
{
visitedHandle.Free();
}
cache.Clear();
}
private static int TraverseTypeClear(IntPtr ob, IntPtr arg)
{
var visited = (HashSet)GCHandle.FromIntPtr(arg).Target;
if (!visited.Add(ob))
{
return 0;
}
var clrObj = ManagedType.GetManagedObject(ob);
if (clrObj != null)
{
clrObj.CallTypeTraverse(TraverseTypeClear, arg);
clrObj.CallTypeClear();
}
return 0;
}
internal static void SaveRuntimeData(RuntimeDataStorage storage)
{
var contexts = storage.AddValue("contexts",
new Dictionary());
storage.AddValue("cache", cache);
foreach (var cls in cache)
{
if (!cls.Key.Valid)
{
// Don't serialize an invalid class
continue;
}
// This incref is for cache to hold the cls,
// thus no need for decreasing it at RestoreRuntimeData.
Runtime.XIncref(cls.Value.pyHandle);
var context = contexts[cls.Value.pyHandle] = new InterDomainContext();
cls.Value.Save(context);
// Remove all members added in InitBaseClass.
// this is done so that if domain reloads and a member of a
// reflected dotnet class is removed, it is removed from the
// Python object's dictionary tool; thus raising an AttributeError
// instead of a TypeError.
// Classes are re-initialized on in RestoreRuntimeData.
IntPtr dict = Marshal.ReadIntPtr(cls.Value.tpHandle, TypeOffset.tp_dict);
foreach (var member in cls.Value.dotNetMembers)
{
// No need to decref the member, the ClassBase instance does
// not own the reference.
if ((Runtime.PyDict_DelItemString(dict, member) == -1) &&
(Exceptions.ExceptionMatches(Exceptions.KeyError)))
{
// Trying to remove a key that's not in the dictionary
// raises an error. We don't care about it.
Runtime.PyErr_Clear();
}
else if (Exceptions.ErrorOccurred())
{
throw new PythonException();
}
}
// We modified the Type object, notify it we did.
Runtime.PyType_Modified(cls.Value.tpHandle);
}
}
internal static Dictionary RestoreRuntimeData(RuntimeDataStorage storage)
{
cache = storage.GetValue("cache");
var invalidClasses = new List();
var contexts = storage.GetValue ("contexts");
var loadedObjs = new Dictionary();
foreach (var pair in cache)
{
if (!pair.Key.Valid)
{
invalidClasses.Add(pair);
continue;
}
// re-init the class
InitClassBase(pair.Key.Value, pair.Value);
// We modified the Type object, notify it we did.
Runtime.PyType_Modified(pair.Value.tpHandle);
var context = contexts[pair.Value.pyHandle];
pair.Value.Load(context);
loadedObjs.Add(pair.Value, context);
}
foreach (var pair in invalidClasses)
{
cache.Remove(pair.Key);
Runtime.XDecref(pair.Value.pyHandle);
}
return loadedObjs;
}
///
/// Return the ClassBase-derived instance that implements a particular
/// reflected managed type, creating it if it doesn't yet exist.
///
/// A Borrowed reference to the ClassBase object
internal static ClassBase GetClass(Type type)
{
ClassBase cb = null;
cache.TryGetValue(type, out cb);
if (cb != null)
{
return cb;
}
cb = CreateClass(type);
cache.Add(type, cb);
// Initialize the object later, as this might call this GetClass method
// recursively (for example when a nested class inherits its declaring class...)
InitClassBase(type, cb);
return cb;
}
///
/// Create a new ClassBase-derived instance that implements a reflected
/// managed type. The new object will be associated with a generated
/// Python type object.
///
private static ClassBase CreateClass(Type type)
{
// Next, select the appropriate managed implementation class.
// Different kinds of types, such as array types or interface
// types, want to vary certain implementation details to make
// sure that the type semantics are consistent in Python.
ClassBase impl;
// Check to see if the given type extends System.Exception. This
// lets us check once (vs. on every lookup) in case we need to
// wrap Exception-derived types in old-style classes
if (type.ContainsGenericParameters)
{
impl = new GenericType(type);
}
else if (type.IsSubclassOf(dtype))
{
impl = new DelegateObject(type);
}
else if (type.IsArray)
{
impl = new ArrayObject(type);
}
else if (type.IsInterface)
{
impl = new InterfaceObject(type);
}
else if (type == typeof(Exception) ||
type.IsSubclassOf(typeof(Exception)))
{
impl = new ExceptionClassObject(type);
}
else if (null != type.GetField("__pyobj__"))
{
impl = new ClassDerivedObject(type);
}
else
{
impl = new ClassObject(type);
}
return impl;
}
private static void InitClassBase(Type type, ClassBase impl)
{
// First, we introspect the managed type and build some class
// information, including generating the member descriptors
// that we'll be putting in the Python class __dict__.
ClassInfo info = GetClassInfo(type);
impl.indexer = info.indexer;
impl.richcompare = new Dictionary();
// Now we allocate the Python type object to reflect the given
// managed type, filling the Python type slots with thunks that
// point to the managed methods providing the implementation.
IntPtr tp = TypeManager.GetTypeHandle(impl, type);
// Finally, initialize the class __dict__ and return the object.
IntPtr dict = Marshal.ReadIntPtr(tp, TypeOffset.tp_dict);
if (impl.dotNetMembers == null)
{
impl.dotNetMembers = new List();
}
IDictionaryEnumerator iter = info.members.GetEnumerator();
while (iter.MoveNext())
{
var item = (ManagedType)iter.Value;
var name = (string)iter.Key;
impl.dotNetMembers.Add(name);
Runtime.PyDict_SetItemString(dict, name, item.pyHandle);
// Decref the item now that it's been used.
item.DecrRefCount();
if (ClassBase.CilToPyOpMap.TryGetValue(name, out var pyOp)) {
impl.richcompare.Add(pyOp, (MethodObject)item);
}
}
// If class has constructors, generate an __doc__ attribute.
IntPtr doc = IntPtr.Zero;
Type marker = typeof(DocStringAttribute);
var attrs = (Attribute[])type.GetCustomAttributes(marker, false);
if (attrs.Length == 0)
{
doc = IntPtr.Zero;
}
else
{
var attr = (DocStringAttribute)attrs[0];
string docStr = attr.DocString;
doc = Runtime.PyString_FromString(docStr);
Runtime.PyDict_SetItem(dict, PyIdentifier.__doc__, doc);
Runtime.XDecref(doc);
}
var co = impl as ClassObject;
// If this is a ClassObject AND it has constructors, generate a __doc__ attribute.
// required that the ClassObject.ctors be changed to internal
if (co != null)
{
if (co.NumCtors > 0)
{
// Implement Overloads on the class object
if (!CLRModule._SuppressOverloads)
{
var ctors = new ConstructorBinding(type, tp, co.binder);
// ExtensionType types are untracked, so don't Incref() them.
// TODO: deprecate __overloads__ soon...
Runtime.PyDict_SetItem(dict, PyIdentifier.__overloads__, ctors.pyHandle);
Runtime.PyDict_SetItem(dict, PyIdentifier.Overloads, ctors.pyHandle);
ctors.DecrRefCount();
}
// don't generate the docstring if one was already set from a DocStringAttribute.
if (!CLRModule._SuppressDocs && doc == IntPtr.Zero)
{
doc = co.GetDocString();
Runtime.PyDict_SetItem(dict, PyIdentifier.__doc__, doc);
Runtime.XDecref(doc);
}
}
}
// The type has been modified after PyType_Ready has been called
// Refresh the type
Runtime.PyType_Modified(tp);
}
internal static bool ShouldBindMethod(MethodBase mb)
{
return (mb.IsPublic || mb.IsFamily || mb.IsFamilyOrAssembly);
}
internal static bool ShouldBindField(FieldInfo fi)
{
return (fi.IsPublic || fi.IsFamily || fi.IsFamilyOrAssembly);
}
internal static bool ShouldBindProperty(PropertyInfo pi)
{
MethodInfo mm = null;
try
{
mm = pi.GetGetMethod(true);
if (mm == null)
{
mm = pi.GetSetMethod(true);
}
}
catch (SecurityException)
{
// GetGetMethod may try to get a method protected by
// StrongNameIdentityPermission - effectively private.
return false;
}
if (mm == null)
{
return false;
}
return ShouldBindMethod(mm);
}
internal static bool ShouldBindEvent(EventInfo ei)
{
return ShouldBindMethod(ei.GetAddMethod(true));
}
private static ClassInfo GetClassInfo(Type type)
{
var ci = new ClassInfo();
var methods = new Hashtable();
ArrayList list;
MethodInfo meth;
ManagedType ob;
string name;
object item;
Type tp;
int i, n;
MemberInfo[] info = type.GetMembers(BindingFlags);
var local = new Hashtable();
var items = new ArrayList();
MemberInfo m;
// Loop through once to find out which names are declared
for (i = 0; i < info.Length; i++)
{
m = info[i];
if (m.DeclaringType == type)
{
local[m.Name] = 1;
}
}
// Now again to filter w/o losing overloaded member info
for (i = 0; i < info.Length; i++)
{
m = info[i];
if (local[m.Name] != null)
{
items.Add(m);
}
}
if (type.IsInterface)
{
// Interface inheritance seems to be a different animal:
// more contractual, less structural. Thus, a Type that
// represents an interface that inherits from another
// interface does not return the inherited interface's
// methods in GetMembers. For example ICollection inherits
// from IEnumerable, but ICollection's GetMemebers does not
// return GetEnumerator.
//
// Not sure if this is the correct way to fix this, but it
// seems to work. Thanks to Bruce Dodson for the fix.
Type[] inheritedInterfaces = type.GetInterfaces();
for (i = 0; i < inheritedInterfaces.Length; ++i)
{
Type inheritedType = inheritedInterfaces[i];
MemberInfo[] imembers = inheritedType.GetMembers(BindingFlags);
for (n = 0; n < imembers.Length; n++)
{
m = imembers[n];
if (local[m.Name] == null)
{
items.Add(m);
}
}
}
// All interface implementations inherit from Object,
// but GetMembers don't return them either.
var objFlags = BindingFlags.Public | BindingFlags.Instance;
foreach (var mi in typeof(object).GetMembers(objFlags))
{
if (local[mi.Name] == null)
{
items.Add(mi);
}
}
}
for (i = 0; i < items.Count; i++)
{
var mi = (MemberInfo)items[i];
switch (mi.MemberType)
{
case MemberTypes.Method:
meth = (MethodInfo)mi;
if (!ShouldBindMethod(meth))
{
continue;
}
name = meth.Name;
item = methods[name];
if (item == null)
{
item = methods[name] = new ArrayList();
}
list = (ArrayList)item;
list.Add(meth);
continue;
case MemberTypes.Property:
var pi = (PropertyInfo)mi;
if(!ShouldBindProperty(pi))
{
continue;
}
// Check for indexer
ParameterInfo[] args = pi.GetIndexParameters();
if (args.GetLength(0) > 0)
{
Indexer idx = ci.indexer;
if (idx == null)
{
ci.indexer = new Indexer();
idx = ci.indexer;
}
idx.AddProperty(pi);
continue;
}
ob = new PropertyObject(pi);
ci.members[pi.Name] = ob;
continue;
case MemberTypes.Field:
var fi = (FieldInfo)mi;
if (!ShouldBindField(fi))
{
continue;
}
ob = new FieldObject(fi);
ci.members[mi.Name] = ob;
continue;
case MemberTypes.Event:
var ei = (EventInfo)mi;
if (!ShouldBindEvent(ei))
{
continue;
}
ob = new EventObject(ei);
ci.members[ei.Name] = ob;
continue;
case MemberTypes.NestedType:
tp = (Type)mi;
if (!(tp.IsNestedPublic || tp.IsNestedFamily ||
tp.IsNestedFamORAssem))
{
continue;
}
// Note the given instance might be uninitialized
ob = GetClass(tp);
// GetClass returns a Borrowed ref. ci.members owns the reference.
ob.IncrRefCount();
ci.members[mi.Name] = ob;
continue;
}
}
IDictionaryEnumerator iter = methods.GetEnumerator();
while (iter.MoveNext())
{
name = (string)iter.Key;
list = (ArrayList)iter.Value;
var mlist = (MethodInfo[])list.ToArray(typeof(MethodInfo));
ob = new MethodObject(type, name, mlist);
ci.members[name] = ob;
if (mlist.Any(OperatorMethod.IsOperatorMethod))
{
string pyName = OperatorMethod.GetPyMethodName(name);
string pyNameReverse = OperatorMethod.ReversePyMethodName(pyName);
OperatorMethod.FilterMethods(mlist, out var forwardMethods, out var reverseMethods);
// Only methods where the left operand is the declaring type.
if (forwardMethods.Length > 0)
ci.members[pyName] = new MethodObject(type, name, forwardMethods);
// Only methods where only the right operand is the declaring type.
if (reverseMethods.Length > 0)
ci.members[pyNameReverse] = new MethodObject(type, name, reverseMethods);
}
}
if (ci.indexer == null && type.IsClass)
{
// Indexer may be inherited.
var parent = type.BaseType;
while (parent != null && ci.indexer == null)
{
foreach (var prop in parent.GetProperties()) {
var args = prop.GetIndexParameters();
if (args.GetLength(0) > 0)
{
ci.indexer = new Indexer();
ci.indexer.AddProperty(prop);
break;
}
}
parent = parent.BaseType;
}
}
return ci;
}
///
/// This class owns references to PyObjects in the `members` member.
/// The caller has responsibility to DECREF them.
///
private class ClassInfo
{
public Indexer indexer;
public Hashtable members;
internal ClassInfo()
{
members = new Hashtable();
indexer = null;
}
}
}
}