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Split from PR 958: restoring the __import__ after shutdown. #993

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Merged
merged 1 commit into from
Nov 21, 2019
Merged

Split from PR 958: restoring the __import__ after shutdown. #993

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67 changes: 54 additions & 13 deletions src/runtime/importhook.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -26,25 +26,64 @@ internal static void InitializeModuleDef()
#endif

/// <summary>
/// Initialization performed on startup of the Python runtime.
/// Get a <i>New reference</i> to the builtins module.
/// </summary>
internal static void Initialize()
static IntPtr GetNewRefToBuiltins()
{
// 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();
if (Runtime.IsPython3)
{
return Runtime.PyImport_ImportModule("builtins");
}
else
{
// dict is a borrowed ref, no need to decref
IntPtr dict = Runtime.PyImport_GetModuleDict();

IntPtr mod = Runtime.IsPython3
? Runtime.PyImport_ImportModule("builtins")
: Runtime.PyDict_GetItemString(dict, "__builtin__");
// GetItemString is a borrowed ref; incref to get a new ref
IntPtr builtins = Runtime.PyDict_GetItemString(dict, "__builtin__");
Runtime.XIncref(builtins);
return builtins;
}
}

py_import = Runtime.PyObject_GetAttrString(mod, "__import__");
/// <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 = GetNewRefToBuiltins();
py_import = Runtime.PyObject_GetAttrString(builtins, "__import__");
hook = new MethodWrapper(typeof(ImportHook), "__import__", "TernaryFunc");
Runtime.PyObject_SetAttrString(mod, "__import__", hook.ptr);
Runtime.PyObject_SetAttrString(builtins, "__import__", hook.ptr);
Runtime.XDecref(hook.ptr);
Runtime.XDecref(builtins);
}

/// <summary>
/// Restore the __import__ hook.
/// </summary>
static void RestoreImport()
{
IntPtr builtins = GetNewRefToBuiltins();

Runtime.PyObject_SetAttrString(builtins, "__import__", py_import);
Runtime.XDecref(py_import);
py_import = IntPtr.Zero;

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();

#if PYTHON3
Expand All @@ -62,6 +101,7 @@ internal static void Initialize()
Runtime.XIncref(root.pyHandle); // we are using the module two times
py_clr_module = root.pyHandle; // Alias handle for PY2/PY3
#endif
IntPtr dict = Runtime.PyImport_GetModuleDict();
Runtime.PyDict_SetItemString(dict, "CLR", py_clr_module);
Runtime.PyDict_SetItemString(dict, "clr", py_clr_module);
}
Expand All @@ -74,9 +114,10 @@ internal static void Shutdown()
{
if (Runtime.Py_IsInitialized() != 0)
{
RestoreImport();

Runtime.XDecref(py_clr_module);
Runtime.XDecref(root.pyHandle);
Runtime.XDecref(py_import);
}
}

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