pythonnet/src/runtime/importhook.cs at master · sdpython/pythonnet · GitHub

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using System;

using System.Collections.Generic;

using System.Runtime.InteropServices;

namespace Python.Runtime

{

/// <summary>

/// Implements the "import hook" used to integrate Python with the CLR.

/// </summary>

internal static class ImportHook

{

private static IntPtr py_import;

private static CLRModule root;

private static MethodWrapper hook;

private static IntPtr py_clr_module;

private static IntPtr module_def = IntPtr.Zero;

internal static void InitializeModuleDef()

{

if (module_def == IntPtr.Zero)

{

module_def = ModuleDefOffset.AllocModuleDef("clr");

}

internal static void ReleaseModuleDef()

{

if (module_def == IntPtr.Zero)

{

return;

}

ModuleDefOffset.FreeModuleDef(module_def);

module_def = IntPtr.Zero;

}

/// <summary>

/// Initialize just the __import__ hook itself.

/// </summary>

static void InitImport()

{

// We replace the built-in Python __import__ with our own: first

// look in CLR modules, then if we don't find any call the default

// Python __import__.

IntPtr builtins = Runtime.GetBuiltins();

py_import = Runtime.PyObject_GetAttr(builtins, PyIdentifier.__import__);

PythonException.ThrowIfIsNull(py_import);

hook = new MethodWrapper(typeof(ImportHook), "__import__", "TernaryFunc");

int res = Runtime.PyObject_SetAttr(builtins, PyIdentifier.__import__, hook.ptr);

PythonException.ThrowIfIsNotZero(res);

Runtime.XDecref(builtins);

}

/// <summary>

/// Restore the __import__ hook.

/// </summary>

static void RestoreImport()

{

IntPtr builtins = Runtime.GetBuiltins();

int res = Runtime.PyObject_SetAttr(builtins, PyIdentifier.__import__, py_import);

PythonException.ThrowIfIsNotZero(res);

Runtime.XDecref(py_import);

py_import = IntPtr.Zero;

hook.Release();

hook = null;

Runtime.XDecref(builtins);

}

/// <summary>

/// Initialization performed on startup of the Python runtime.

/// </summary>

internal static void Initialize()

{

InitImport();

// Initialize the clr module and tell Python about it.

root = new CLRModule();

// create a python module with the same methods as the clr module-like object

InitializeModuleDef();

py_clr_module = Runtime.PyModule_Create2(module_def, 3);

// both dicts are borrowed references

IntPtr mod_dict = Runtime.PyModule_GetDict(py_clr_module);

IntPtr clr_dict = Runtime._PyObject_GetDictPtr(root.pyHandle); // PyObject**

clr_dict = (IntPtr)Marshal.PtrToStructure(clr_dict, typeof(IntPtr));

Runtime.PyDict_Update(mod_dict, clr_dict);

IntPtr dict = Runtime.PyImport_GetModuleDict();

Runtime.PyDict_SetItemString(dict, "CLR", py_clr_module);

Runtime.PyDict_SetItemString(dict, "clr", py_clr_module);

}

/// <summary>

/// Cleanup resources upon shutdown of the Python runtime.

/// </summary>

internal static void Shutdown()

{

if (Runtime.Py_IsInitialized() == 0)

{

return;

}

RestoreImport();

bool shouldFreeDef = Runtime.Refcount(py_clr_module) == 1;

Runtime.XDecref(py_clr_module);

py_clr_module = IntPtr.Zero;

if (shouldFreeDef)

{

ReleaseModuleDef();

}

Runtime.XDecref(root.pyHandle);

root = null;

CLRModule.Reset();

}

internal static void SaveRuntimeData(RuntimeDataStorage storage)

{

// Increment the reference counts here so that the objects don't

// get freed in Shutdown.

Runtime.XIncref(py_clr_module);

Runtime.XIncref(root.pyHandle);

storage.AddValue("py_clr_module", py_clr_module);

storage.AddValue("root", root.pyHandle);

}

internal static void RestoreRuntimeData(RuntimeDataStorage storage)

{

InitImport();

storage.GetValue("py_clr_module", out py_clr_module);

var rootHandle = storage.GetValue<IntPtr>("root");

root = (CLRModule)ManagedType.GetManagedObject(rootHandle);

}

/// <summary>

/// Return the clr python module (new reference)

/// </summary>

public static IntPtr GetCLRModule(IntPtr? fromList = null)

{

root.InitializePreload();

// update the module dictionary with the contents of the root dictionary

root.LoadNames();

IntPtr py_mod_dict = Runtime.PyModule_GetDict(py_clr_module);

IntPtr clr_dict = Runtime._PyObject_GetDictPtr(root.pyHandle); // PyObject**

clr_dict = (IntPtr)Marshal.PtrToStructure(clr_dict, typeof(IntPtr));

Runtime.PyDict_Update(py_mod_dict, clr_dict);

// find any items from the from list and get them from the root if they're not

// already in the module dictionary

if (fromList != null && fromList != IntPtr.Zero)

{

if (Runtime.PyTuple_Check(fromList.GetValueOrDefault()))

{

Runtime.XIncref(py_mod_dict);

using (var mod_dict = new PyDict(py_mod_dict))

{

Runtime.XIncref(fromList.GetValueOrDefault());

using (var from = new PyTuple(fromList.GetValueOrDefault()))

{

foreach (PyObject item in from)

{

if (mod_dict.HasKey(item))

{

continue;

}

var s = item.AsManagedObject(typeof(string)) as string;

if (s == null)

{

continue;

}

ManagedType attr = root.GetAttribute(s, true);

if (attr == null)

{

continue;

}

Runtime.XIncref(attr.pyHandle);

using (var obj = new PyObject(attr.pyHandle))

{

mod_dict.SetItem(s, obj);

}

Runtime.XIncref(py_clr_module);

return py_clr_module;

}

/// <summary>

/// The actual import hook that ties Python to the managed world.

/// </summary>

public static IntPtr __import__(IntPtr self, IntPtr args, IntPtr kw)

{

// Replacement for the builtin __import__. The original import

// hook is saved as this.py_import. This version handles CLR

// import and defers to the normal builtin for everything else.

var num_args = Runtime.PyTuple_Size(args);

if (num_args < 1)

{

return Exceptions.RaiseTypeError("__import__() takes at least 1 argument (0 given)");

}

// borrowed reference

IntPtr py_mod_name = Runtime.PyTuple_GetItem(args, 0);

if (py_mod_name == IntPtr.Zero ||

!Runtime.IsStringType(py_mod_name))

{

return Exceptions.RaiseTypeError("string expected");

}

// Check whether the import is of the form 'from x import y'.

// This determines whether we return the head or tail module.

IntPtr fromList = IntPtr.Zero;

var fromlist = false;

if (num_args >= 4)

{

fromList = Runtime.PyTuple_GetItem(args, 3);

if (fromList != IntPtr.Zero &&

Runtime.PyObject_IsTrue(fromList) == 1)

{

fromlist = true;

}

string mod_name = Runtime.GetManagedString(py_mod_name);

// Check these BEFORE the built-in import runs; may as well

// do the Incref()ed return here, since we've already found

// the module.

if (mod_name == "clr")

{

IntPtr clr_module = GetCLRModule(fromList);

if (clr_module != IntPtr.Zero)

{

IntPtr sys_modules = Runtime.PyImport_GetModuleDict();

if (sys_modules != IntPtr.Zero)

{

Runtime.PyDict_SetItemString(sys_modules, "clr", clr_module);

}

return clr_module;

}

string realname = mod_name;

string clr_prefix = null;

// 2010-08-15: Always seemed smart to let python try first...

// This shaves off a few tenths of a second on test_module.py

// and works around a quirk where 'sys' is found by the

// LoadImplicit() deprecation logic.

// Turns out that the AssemblyManager.ResolveHandler() checks to see if any

// Assembly's FullName.ToLower().StartsWith(name.ToLower()), which makes very

// little sense to me.

IntPtr res = Runtime.PyObject_Call(py_import, args, kw);

if (res != IntPtr.Zero)

{

// There was no error.

if (fromlist && IsLoadAll(fromList))

{

var mod = ManagedType.GetManagedObject(res) as ModuleObject;

mod?.LoadNames();

}

return res;

}

// There was an error

if (!Exceptions.ExceptionMatches(Exceptions.ImportError))

{

// and it was NOT an ImportError; bail out here.

return IntPtr.Zero;

}

if (mod_name == string.Empty)

{

// Most likely a missing relative import.

// For example site-packages\bs4\builder\__init__.py uses it to check if a package exists:

// from . import _html5lib

// We don't support them anyway

return IntPtr.Zero;

}

// Save the exception

var originalException = new PythonException();

// Otherwise, just clear the it.

Exceptions.Clear();

string[] names = realname.Split('.');

// See if sys.modules for this interpreter already has the

// requested module. If so, just return the existing module.

IntPtr modules = Runtime.PyImport_GetModuleDict();

IntPtr module = Runtime.PyDict_GetItem(modules, py_mod_name);

if (module != IntPtr.Zero)

{

if (fromlist)

{

if (IsLoadAll(fromList))

{

var mod = ManagedType.GetManagedObject(module) as ModuleObject;

mod?.LoadNames();

}

Runtime.XIncref(module);

return module;

}

if (clr_prefix != null)

{

return GetCLRModule(fromList);

}

module = Runtime.PyDict_GetItemString(modules, names[0]);

Runtime.XIncref(module);

return module;

}

Exceptions.Clear();

// Traverse the qualified module name to get the named module

// and place references in sys.modules as we go. Note that if

// we are running in interactive mode we pre-load the names in

// each module, which is often useful for introspection. If we

// are not interactive, we stick to just-in-time creation of

// objects at lookup time, which is much more efficient.

// NEW: The clr got a new module variable preload. You can

// enable preloading in a non-interactive python processing by

// setting clr.preload = True

ModuleObject head = mod_name == realname ? null : root;

ModuleObject tail = root;

root.InitializePreload();

foreach (string name in names)

{

ManagedType mt = tail.GetAttribute(name, true);

if (!(mt is ModuleObject))

{

originalException.Restore();

return IntPtr.Zero;

}

if (head == null)

{

head = (ModuleObject)mt;

}

tail = (ModuleObject)mt;

if (CLRModule.preload)

{

tail.LoadNames();

}

// Add the module to sys.modules

Runtime.PyDict_SetItemString(modules, tail.moduleName, tail.pyHandle);

// If imported from CLR add clr.<modulename> to sys.modules as well

if (clr_prefix != null)

{

Runtime.PyDict_SetItemString(modules, clr_prefix + tail.moduleName, tail.pyHandle);

}

{

var mod = fromlist ? tail : head;

if (fromlist && IsLoadAll(fromList))

{

mod.LoadNames();

}

Runtime.XIncref(mod.pyHandle);

return mod.pyHandle;

}

private static bool IsLoadAll(IntPtr fromList)

{

if (CLRModule.preload)

{

return false;

}

if (Runtime.PySequence_Size(fromList) != 1)

{

return false;

}

IntPtr fp = Runtime.PySequence_GetItem(fromList, 0);

bool res = Runtime.GetManagedString(fp) == "*";

Runtime.XDecref(fp);

return res;

}

pythonnet/src/runtime/importhook.cs at master · sdpython/pythonnet · GitHub

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