From 6766f149f2778f1b37b094df2cf67cf5fcf02cf2 Mon Sep 17 00:00:00 2001
From: Martyn Gigg <martyn.gigg@gmail.com>
Date: Wed, 11 Jul 2018 22:00:58 +0100
Subject: [PATCH] Add function to retrieve other process ids using psutil
Refs #0
---
MantidPlot/CMakeLists.txt | 2 +
MantidPlot/src/Process.cpp | 111 +++++++++++++++++++++++++++++++++++++
MantidPlot/src/Process.h | 36 ++++++++++++
3 files changed, 149 insertions(+)
create mode 100644 MantidPlot/src/Process.cpp
create mode 100644 MantidPlot/src/Process.h
diff --git a/MantidPlot/CMakeLists.txt b/MantidPlot/CMakeLists.txt
index 7ea2943c40f..b5b9670e1c5 100644
--- a/MantidPlot/CMakeLists.txt
+++ b/MantidPlot/CMakeLists.txt
@@ -91,6 +91,7 @@ set ( QTIPLOT_SRCS src/ApplicationWindow.cpp
src/PluginFit.cpp
src/PolynomFitDialog.cpp
src/PolynomialFit.cpp
+ src/Process.cpp
src/ProjectRecovery.cpp
src/ProjectSaveView.cpp
src/ProjectSerialiser.cpp
@@ -291,6 +292,7 @@ set ( QTIPLOT_HDRS src/ApplicationWindow.h
src/PluginFit.h
src/PolynomFitDialog.h
src/PolynomialFit.h
+ src/Process.h
src/ProjectRecovery.h
src/ProjectSerialiser.h
src/ProjectSaveView.h
diff --git a/MantidPlot/src/Process.cpp b/MantidPlot/src/Process.cpp
new file mode 100644
index 00000000000..24be2e51167
--- /dev/null
+++ b/MantidPlot/src/Process.cpp
@@ -0,0 +1,111 @@
+// clang-format off
+#include "MantidQtWidgets/Common/PythonThreading.h"
+// clang-format on
+
+#include "Process.h"
+
+#include <iostream>
+#include <stdexcept>
+#include <QCoreApplication>
+
+namespace {
+
+class PyObjectNewReference {
+public:
+ PyObjectNewReference(PyObject *object) : m_object(object) {}
+ ~PyObjectNewReference() { Py_XDECREF(m_object); }
+
+ PyObjectNewReference(const PyObjectNewReference &) = delete;
+ PyObjectNewReference &operator=(const PyObjectNewReference &) = delete;
+
+ PyObjectNewReference(PyObjectNewReference &&) = default;
+ PyObjectNewReference &operator=(PyObjectNewReference &&) = default;
+
+ inline PyObject *ptr() const { return m_object; }
+
+private:
+ PyObject *m_object;
+};
+
+/**
+ * @brief Retrieve a named attribute
+ * @param source The source object
+ * @param name The name of the attribute
+ * @return The attribute
+ * @throws std::runtime_error if an error occurs retrieving the attribute
+ */
+PyObjectNewReference attr(PyObject *source, const char *name) {
+ PyObjectNewReference attr(PyObject_GetAttrString(source, name));
+ if (attr.ptr()) {
+ return attr;
+ } else {
+ PyErr_Clear();
+ throw std::runtime_error(std::string("Process: No attribute ") + name +
+ " found");
+ }
+}
+
+/**
+ * @brief Call a named function with an check for errors
+ * @param source The source object
+ * @param name The name of the attribute to call
+ * @return The return value of the function
+ * @throws std::runtime_error if an error occurs retrieving the attribute
+ */
+PyObjectNewReference call(PyObject *source, const char *name) {
+ auto result = PyObject_CallFunction(attr(source, name).ptr(), nullptr);
+ if (result)
+ return PyObjectNewReference(result);
+ else {
+ PyErr_Clear();
+ throw std::runtime_error(std::string("Process: Error calling function ") +
+ name);
+ }
+}
+
+/**
+ * @return Return a pointer to the psutil module. A new reference is returned.
+ */
+PyObjectNewReference psutil() {
+ if (auto process = PyImport_ImportModule("psutil")) {
+ return PyObjectNewReference(process);
+ } else {
+ PyErr_Clear();
+ throw std::runtime_error("Python module psutil cannot be imported.");
+ }
+}
+} // namespace
+
+namespace Process {
+
+/**
+ * @brief Return a list of process IDs for other instances of this process.
+ * @return A list of other processes running. The PID for this process is
+ * removed from the list. An empty list is returned
+ * if no other processes are running.
+ * @throws std::runtime_error if the PID list cannot be determined
+ */
+std::vector<int64_t> otherInstancePIDs() {
+ ScopedPythonGIL lock;
+ const int64_t ourPID(QCoreApplication::applicationPid());
+ const PyObjectNewReference ourName(PyString_FromString(
+ QCoreApplication::applicationName().toLatin1().data()));
+ auto psutilModule(psutil());
+ auto processIter(call(psutilModule.ptr(), "process_iter"));
+
+ std::vector<int64_t> otherPIDs;
+ PyObject *item(nullptr);
+ while ((item = PyIter_Next(processIter.ptr()))) {
+ auto name = call(item, "name");
+ if (PyObject_RichCompareBool(name.ptr(), ourName.ptr(), Py_EQ)) {
+ auto pid = PyLong_AsLong(attr(item, "pid").ptr());
+ if (pid != ourPID) {
+ otherPIDs.emplace_back(pid);
+ }
+ }
+ Py_DECREF(item);
+ }
+ return otherPIDs;
+}
+
+} // namespace Process
diff --git a/MantidPlot/src/Process.h b/MantidPlot/src/Process.h
new file mode 100644
index 00000000000..e7740f35ac4
--- /dev/null
+++ b/MantidPlot/src/Process.h
@@ -0,0 +1,36 @@
+#ifndef PROCESS_H_
+#define PROCESS_H_
+/*
+Copyright © 2008-18 ISIS Rutherford Appleton Laboratory, NScD Oak Ridge
+National Laboratory & European Spallation Source
+
+This file is part of Mantid.
+
+Mantid is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3 of the License, or
+(at your option) any later version.
+
+Mantid is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+File change history is stored at: <https://github.com/mantidproject/mantid>
+Code Documentation is available at: <http://doxygen.mantidproject.org>
+*/
+#include <cstdint>
+#include <vector>
+
+/*
+ * A minimal wrapper around Python's psutil package to gather information
+ * about processes
+ */
+
+namespace Process {
+std::vector<int64_t> otherInstancePIDs();
+}
+#endif // PROCESS_H_
--
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