// ==========================================================================

// 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.Threading;

namespace Python.Runtime {

/// <summary>

/// This class provides the public interface of the Python runtime.

/// </summary>

public class PythonEngine {

private static bool initialized;

#region Properties

public static bool IsInitialized {

get {

return initialized;

}

}

public static string ProgramName {

get {

string result = Runtime.Py_GetProgramName();

if (result == null) {

return "";

}

return result;

}

set {

Runtime.Py_SetProgramName(value);

}

}

public static string PythonHome {

get {

string result = Runtime.Py_GetPythonHome();

if (result == null) {

return "";

}

return result;

}

set {

Runtime.Py_SetPythonHome(value);

}

}

public static string Version {

get {

return Runtime.Py_GetVersion();

}

}

public static string BuildInfo {

get {

return Runtime.Py_GetBuildInfo();

}

}

public static string Platform {

get {

return Runtime.Py_GetPlatform();

}

}

public static string Copyright {

get {

return Runtime.Py_GetCopyright();

}

}

public static int RunSimpleString(string code) {

return Runtime.PyRun_SimpleString(code);

}

#endregion

/// <summary>

/// Initialize Method

/// </summary>

///

/// <remarks>

/// Initialize the Python runtime. It is safe to call this method

/// more than once, though initialization will only happen on the

/// first call. It is *not* necessary to hold the Python global

/// interpreter lock (GIL) to call this method.

/// </remarks>

public static void Initialize() {

if (!initialized) {

Runtime.Initialize();

initialized = true;

Exceptions.Clear();

}

}

//====================================================================

// A helper to perform initialization from the context of an active

// CPython interpreter process - this bootstraps the managed runtime

// when it is imported by the CLR extension module.

//====================================================================

public static void InitExt() {

Initialize();

// Trickery - when the import hook is installed into an already

// running Python, the standard import machinery is still in

// control for the duration of the import that caused bootstrap.

//

// That is problematic because the std machinery tries to get

// sub-names directly from the module __dict__ rather than going

// through our module object's getattr hook. This workaround is

// evil ;) We essentially climb up the stack looking for the

// import that caused the bootstrap to happen, then re-execute

// the import explicitly after our hook has been installed. By

// doing this, the original outer import should work correctly.

//

// Note that this is only needed during the execution of the

// first import that installs the CLR import hook. This hack

// still doesn't work if you use the interactive interpreter,

// since there is no line info to get the import line ;(

string code =

"import traceback\n" +

"for item in traceback.extract_stack():\n" +

" line = item[3]\n" +

" if line is not None:\n" +

" if line.startswith('import CLR') or \\\n" +

" line.startswith('from CLR'):\n" +

" exec line\n" +

" break\n";

PyObject r = PythonEngine.RunString(code);

if (r != null) {

r.Dispose();

}

}

/// <summary>

/// Shutdown Method

/// </summary>

///

/// <remarks>

/// Shutdown and release resources held by the Python runtime. The

/// Python runtime can no longer be used in the current process

/// after calling the Shutdown method.

/// </remarks>

public static void Shutdown() {

if (initialized) {

Runtime.Shutdown();

initialized = false;

}

}

/// <summary>

/// AcquireLock Method

/// </summary>

///

/// <remarks>

/// Acquire the Python global interpreter lock (GIL). Managed code

/// *must* call this method before using any objects or calling any

/// methods on objects in the Python.Runtime namespace. The only

/// exception is PythonEngine.Initialize, which may be called without

/// first calling AcquireLock.

///

/// Each call to AcquireLock must be matched by a corresponding call

/// to ReleaseLock, passing the token obtained from AcquireLock.

///

/// For more information, see the "Extending and Embedding" section

/// of the Python documentation on www.python.org.

/// </remarks>

public static IntPtr AcquireLock() {

return Runtime.PyGILState_Ensure();

}

/// <summary>

/// ReleaseLock Method

/// </summary>

///

/// <remarks>

/// Release the Python global interpreter lock using a token obtained

/// from a previous call to AcquireLock.

///

/// For more information, see the "Extending and Embedding" section

/// of the Python documentation on www.python.org.

/// </remarks>

public static void ReleaseLock(IntPtr gs) {

Runtime.PyGILState_Release(gs);

}

/// <summary>

/// BeginAllowThreads Method

/// </summary>

///

/// <remarks>

/// Release the Python global interpreter lock to allow other threads

/// to run. This is equivalent to the Py_BEGIN_ALLOW_THREADS macro

/// provided by the C Python API.

///

/// For more information, see the "Extending and Embedding" section

/// of the Python documentation on www.python.org.

/// </remarks>

public static IntPtr BeginAllowThreads() {

return Runtime.PyEval_SaveThread();

}

/// <summary>

/// EndAllowThreads Method

/// </summary>

///

/// <remarks>

/// Re-aquire the Python global interpreter lock for the current

/// thread. This is equivalent to the Py_END_ALLOW_THREADS macro

/// provided by the C Python API.

///

/// For more information, see the "Extending and Embedding" section

/// of the Python documentation on www.python.org.

/// </remarks>

public static void EndAllowThreads(IntPtr ts) {

Runtime.PyEval_RestoreThread(ts);

}

/// <summary>

/// ImportModule Method

/// </summary>

///

/// <remarks>

/// Given a fully-qualified module or package name, import the

/// module and return the resulting module object as a PyObject

/// or null if an exception is raised.

/// </remarks>

public static PyObject ImportModule(string name) {

IntPtr op = Runtime.PyImport_ImportModule(name);

if (op == IntPtr.Zero) {

return null;

}

return new PyObject(op);

}

/// <summary>

/// ReloadModule Method

/// </summary>

///

/// <remarks>

/// Given a PyObject representing a previously loaded module, reload

/// the module.

/// </remarks>

public static PyObject ReloadModule(PyObject module) {

IntPtr op = Runtime.PyImport_ReloadModule(module.Handle);

if (op == IntPtr.Zero) {

throw new PythonException();

}

return new PyObject(op);

}

/// <summary>

/// ModuleFromString Method

/// </summary>

///

/// <remarks>

/// Given a string module name and a string containing Python code,

/// execute the code in and return a module of the given name.

/// </remarks>

public static PyObject ModuleFromString(string name, string code) {

IntPtr c = Runtime.Py_CompileString(code, "none", (IntPtr)257);

if (c == IntPtr.Zero) {

throw new PythonException();

}

IntPtr m = Runtime.PyImport_ExecCodeModule(name, c);

if (m == IntPtr.Zero) {

throw new PythonException();

}

return new PyObject(m);

}

/// <summary>

/// RunString Method

/// </summary>

///

/// <remarks>

/// Run a string containing Python code. Returns the result of

/// executing the code string as a PyObject instance, or null if

/// an exception was raised.

/// </remarks>

public static PyObject RunString(string code) {

IntPtr globals = Runtime.PyEval_GetGlobals();

IntPtr locals = Runtime.PyDict_New();

IntPtr builtins = Runtime.PyEval_GetBuiltins();

Runtime.PyDict_SetItemString(locals, "__builtins__", builtins);

IntPtr flag = (IntPtr)257; /* Py_file_input */

IntPtr result = Runtime.PyRun_String(code, flag, globals, locals);

Runtime.Decref(locals);

if (result == IntPtr.Zero) {

return null;

}

return new PyObject(result);

}

}

}