First checkin of the Python XPCOM bindings.

git-svn-id: svn://10.0.0.236/trunk@87331 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/extensions/python/xpcom/src/PyGStub.cpp

@@ -0,0 +1,144 @@
+/* Copyright (c) 2000-2001 ActiveState Tool Corporation.
+   See the file LICENSE.txt for licensing information. */
+
+// PyXPTStub - the stub for implementing interfaces.
+//
+// This code is part of the XPCOM extensions for Python.
+//
+// Written May 2000 by Mark Hammond.
+//
+// Based heavily on the Python COM support, which is
+// (c) Mark Hammond and Greg Stein.
+//
+// (c) 2000, ActiveState corp.
+
+#include "PyXPCOM_std.h"
+#include <nsIInterfaceInfoManager.h>
+
+void *PyXPCOM_XPTStub::ThisAsIID(const nsIID &iid)
+{
+	if (iid.Equals(NS_GET_IID(nsISupports)))
+	    return (nsISupports *)(nsXPTCStubBase *)this;
+	else if (iid.Equals(m_iid))
+		return (nsISupports *)(nsXPTCStubBase *)this;
+	else
+		return PyG_Base::ThisAsIID(iid);
+}
+
+
+NS_IMETHODIMP
+PyXPCOM_XPTStub::GetInterfaceInfo(nsIInterfaceInfo** info)
+{
+	NS_PRECONDITION(info, "NULL pointer");
+	if (info==nsnull)
+		return NS_ERROR_NULL_POINTER;
+	// Simply get the XPCOM runtime to provide this
+	// (but there must be some reason why they dont get it themselves!?
+	// Maybe because they dont know the IID?
+	nsCOMPtr<nsIInterfaceInfoManager> iim = XPTI_GetInterfaceInfoManager();
+	NS_ABORT_IF_FALSE(iim != nsnull, "Cant get interface from IIM!");
+	if (iim==nsnull)
+		return NS_ERROR_FAILURE;
+
+	return iim->GetInfoForIID( &m_iid, info);
+}
+
+// call this method and return result
+NS_IMETHODIMP
+PyXPCOM_XPTStub::CallMethod(PRUint16 methodIndex,
+                          const nsXPTMethodInfo* info,
+                          nsXPTCMiniVariant* params)
+{
+	nsresult rc = NS_ERROR_FAILURE;
+	NS_PRECONDITION(info, "NULL methodinfo pointer");
+	NS_PRECONDITION(params, "NULL variant pointer");
+	CEnterLeavePython _celp;
+	PyObject *obParams = NULL;
+	PyObject *result = NULL;
+	PyObject *obThisObject = NULL;
+	PyObject *obMI = PyObject_FromXPTMethodDescriptor(info);
+	PyXPCOM_GatewayVariantHelper arg_helper(this, methodIndex, info, params);
+	if (obMI==NULL)
+		goto done;
+	// base object is passed raw.
+	obThisObject = Py_nsISupports::PyObjectFromInterface((nsIInternalPython*)this, NS_GET_IID(nsISupports), PR_TRUE, PR_FALSE);
+	obParams = arg_helper.MakePyArgs();
+	if (obParams==NULL)
+		goto done;
+	result = PyObject_CallMethod(m_pPyObject, 
+	                                       "_CallMethod_",
+					       "OiOO",
+					       obThisObject,
+					       (int)methodIndex,
+					       obMI,
+					       obParams);
+	if (result!=NULL) {
+		rc = arg_helper.ProcessPythonResult(result);
+		// Use an xor to check failure && pyerr, or !failure && !pyerr.
+		NS_ABORT_IF_FALSE( ((NS_FAILED(rc)!=0)^(PyErr_Occurred()!=0)) == 0, "We must have failure with a Python error, or success without a Python error.");
+	}
+done:
+	if (PyErr_Occurred()) {
+		// The error handling - fairly involved, but worth it as
+		// good error reporting is critical for users to know WTF 
+		// is going on - especially with TypeErrors etc in their
+		// return values (ie, after the Python code has successfully
+		// existed, but we encountered errors unpacking their
+		// result values for the COM caller - there is literally no 
+		// way to catch these exceptions from Python code, as their
+		// is no Python function on the call-stack)
+
+		// First line of attack in an error is to call-back on the policy.
+		// If the callback of the error handler succeeds and returns an
+		// integer (for the nsresult), we take no further action.
+
+		// If this callback fails, we log _2_ exceptions - the error handler
+		// error, and the original error.
+
+		PRBool bProcessMainError = PR_TRUE; // set to false if our exception handler does its thing!
+		PyObject *exc_typ, *exc_val, *exc_tb;
+		PyErr_Fetch(&exc_typ, &exc_val, &exc_tb);
+		PyErr_NormalizeException( &exc_typ, &exc_val, &exc_tb);
+
+		PyObject *err_result = PyObject_CallMethod(m_pPyObject, 
+	                                       "_CallMethodException_",
+					       "OiOO(OOO)",
+					       obThisObject,
+					       (int)methodIndex,
+					       obMI,
+					       obParams,
+		                               exc_typ ? exc_typ : Py_None, // should never be NULL, but defensive programming...
+		                               exc_val ? exc_val : Py_None, // may well be NULL.
+					       exc_tb ? exc_tb : Py_None); // may well be NULL.
+		if (err_result == NULL) {
+			PyXPCOM_LogError("The exception handler _CallMethodException_ failed!\n");
+		} else if (err_result == Py_None) {
+			// The exception handler has chosen not to do anything with
+			// this error, so we still need to print it!
+			;
+		} else if (PyInt_Check(err_result)) {
+			// The exception handler has given us the nresult.
+			rc = PyInt_AsLong(err_result);
+			bProcessMainError = PR_FALSE;
+		} else {
+			// The exception handler succeeded, but returned other than
+			// int or None.
+			PyXPCOM_LogError("The _CallMethodException_ handler returned object of type '%s' - None or an integer expected\n", err_result->ob_type->tp_name);
+		}
+		Py_XDECREF(err_result);
+		PyErr_Restore(exc_typ, exc_val, exc_tb);
+		if (bProcessMainError) {
+			PyXPCOM_LogError("The function '%s' failed\n", info->GetName());
+			rc = PyXPCOM_SetCOMErrorFromPyException();
+		}
+		// else everything is already setup,
+		// just clear the Python error state.
+		PyErr_Clear();
+	}
+
+	Py_XDECREF(obMI);
+	Py_XDECREF(obParams);
+	Py_XDECREF(obThisObject);
+	Py_XDECREF(result);
+	return rc;
+}