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Copy pathimporthook.cs
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executable file
·207 lines (162 loc) · 6.62 KB
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// ==========================================================================
// 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;
namespace Python.Runtime {
//========================================================================
// Implements the "import hook" used to integrate Python with the CLR.
//========================================================================
internal class ImportHook {
static IntPtr py_import;
static ModuleObject root;
static MethodWrapper hook;
static int preload;
//===================================================================
// Initialization performed on startup of the Python runtime.
//===================================================================
internal static void Initialize() {
// Initialize the Python <--> CLR module hook. We replace the
// built-in Python __import__ with our own. This isn't ideal,
// but it provides the most "Pythonic" way of dealing with CLR
// modules (Python doesn't provide a way to emulate packages).
IntPtr dict = Runtime.PyImport_GetModuleDict();
IntPtr mod = Runtime.PyDict_GetItemString(dict, "__builtin__");
py_import = Runtime.PyObject_GetAttrString(mod, "__import__");
hook = new MethodWrapper(typeof(ImportHook), "__import__");
Runtime.PyObject_SetAttrString(mod, "__import__", hook.ptr);
Runtime.Decref(hook.ptr);
root = new ModuleObject("");
Runtime.PyDict_SetItemString(dict, "CLR", root.pyHandle);
preload = -1;
}
//===================================================================
// Cleanup resources upon shutdown of the Python runtime.
//===================================================================
internal static void Shutdown() {
Runtime.Decref(root.pyHandle);
Runtime.Decref(py_import);
}
//===================================================================
// The actual import hook that ties Python to the managed world.
//===================================================================
[CallConvCdecl()]
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.
int 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;
bool 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);
if (mod_name == "CLR" || mod_name == "clr") {
Runtime.Incref(root.pyHandle);
return root.pyHandle;
}
string realname = mod_name;
if (mod_name.StartsWith("CLR.")) {
realname = mod_name.Substring(4);
}
string[] names = realname.Split('.');
// Now we need to decide if the name refers to a CLR module,
// and may have to do an implicit load (for b/w compatibility)
// using the AssemblyManager. The assembly manager tries
// really hard not to use Python objects or APIs, because
// parts of it can run recursively and on strange threads.
//
// It does need an opportunity from time to time to check to
// see if sys.path has changed, in a context that is safe. Here
// we know we have the GIL, so we'll let it update if needed.
AssemblyManager.UpdatePath();
AssemblyManager.LoadImplicit(realname);
if (!AssemblyManager.IsValidNamespace(realname)) {
return Runtime.PyObject_Call(py_import, args, kw);
}
// See if sys.modules for this interpreter already has the
// requested module. If so, just return the exising module.
IntPtr modules = Runtime.PyImport_GetModuleDict();
IntPtr module = Runtime.PyDict_GetItem(modules, py_mod_name);
if (module != IntPtr.Zero) {
if (fromlist) {
Runtime.Incref(module);
return module;
}
module = Runtime.PyDict_GetItemString(modules, names[0]);
Runtime.Incref(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.
if (preload < 0) {
if (Runtime.PySys_GetObject("ps1") != IntPtr.Zero) {
preload = 1;
}
else {
Exceptions.Clear();
preload = 0;
}
}
ModuleObject head = (mod_name == realname) ? null : root;
ModuleObject tail = root;
for (int i = 0; i < names.Length; i++) {
string name = names[i];
ManagedType mt = tail.GetAttribute(name);
if (!(mt is ModuleObject)) {
string error = String.Format("No module named {0}", name);
Exceptions.SetError(Exceptions.ImportError, error);
return IntPtr.Zero;
}
if (head == null) {
head = (ModuleObject)mt;
}
tail = (ModuleObject) mt;
if (preload == 1) {
tail.LoadNames();
}
Runtime.PyDict_SetItemString(modules, tail.moduleName,
tail.pyHandle
);
}
ModuleObject mod = fromlist ? tail : head;
if (fromlist && Runtime.PySequence_Size(fromList) == 1) {
IntPtr fp = Runtime.PySequence_GetItem(fromList, 0);
if ((preload < 1) && Runtime.GetManagedString(fp) == "*") {
mod.LoadNames();
}
Runtime.Decref(fp);
}
Runtime.Incref(mod.pyHandle);
return mod.pyHandle;
}
}
}