From ab82ea004ffa9e2dfd7f36adc5f6b62199d364fc Mon Sep 17 00:00:00 2001
From: Mark Liversedge <liversedge@gmail.com>
Date: Fri, 24 Nov 2017 19:32:07 +0000
Subject: [PATCH] ESC or ^C to stop long running Python script

.. when a chart script gets caught in a runaway loop let the
   user interrupt it with the ESC or ^C key.
---
 src/Charts/PythonChart.cpp | 24 ++----------------------
 src/Python/PythonEmbed.cpp | 19 +++++++++++++++++++
 src/Python/PythonEmbed.h   |  1 +
 3 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/src/Charts/PythonChart.cpp b/src/Charts/PythonChart.cpp
index 64246914e..c9c21967c 100644
--- a/src/Charts/PythonChart.cpp
+++ b/src/Charts/PythonChart.cpp
@@ -128,17 +128,13 @@ void PythonConsole::keyPressEvent(QKeyEvent *e)
     case Qt::Key_C:
         {
 
-            fprintf(stderr, "ESC PRESSED\n");
-
             Qt::KeyboardModifiers kmod = static_cast<QInputEvent*>(e)->modifiers();
             bool ctrl = (kmod & Qt::ControlModifier) != 0;
 
             if (e->key() == Qt::Key_Escape || ctrl) {
 
                 // are we doing something?
-                if (python && python->canvas) {
-                    python->cancel();
-                }
+                python->cancel();
 
                 // ESC or ^C needs to clear program and go to next line
                 python->program.clear();
@@ -386,7 +382,6 @@ PythonChart::eventFilter(QObject *, QEvent *e)
     // is it an ESC key?
     if (e->type() == QEvent::KeyPress && static_cast<QKeyEvent*>(e)->key() == Qt::Key_Escape) {
         // stop!
-        fprintf(stderr, "ESC hit!\n");
         python->cancel();
         return true;
     }
@@ -453,26 +448,11 @@ PythonChart::setState(QString)
     //if (python && splitter && b != "") splitter->restoreState(QByteArray(b.toLatin1()));
 }
 
-// from PythonEmbed
-extern PyThreadState *mainThreadState;
-
+// this is executed in its own thread.
 void
 PythonChart::execScript(PythonChart *chart)
 {
-    //PyGILState_STATE gstate;
-    //gstate = PyGILState_Ensure();
-    //PyThreadState *myThreadState = PyThreadState_New(mainThreadState->interp);
-
-    // switch to me
-    //PyEval_RestoreThread(myThreadState);
-
-    // exec
     python->runline(chart->script->toPlainText());
-
-    // save my state and release lock
-    // we discard return as we're about to give up anyway
-    //PyEval_SaveThread();
-    //PyGILState_Release(gstate);
 }
 
 void
diff --git a/src/Python/PythonEmbed.cpp b/src/Python/PythonEmbed.cpp
index 41938b8fd..521fb4e4a 100644
--- a/src/Python/PythonEmbed.cpp
+++ b/src/Python/PythonEmbed.cpp
@@ -43,6 +43,7 @@ PythonEmbed::~PythonEmbed()
 PythonEmbed::PythonEmbed(const bool verbose, const bool interactive) : verbose(verbose), interactive(interactive)
 {
     loaded = false;
+    threadid=-1;
     name = QString("GoldenCheetah");
 
     // tell python our program name
@@ -95,6 +96,14 @@ void PythonEmbed::runline(QString line)
     PyGILState_STATE gstate;
     gstate = PyGILState_Ensure();
 
+    // Get current thread ID via Python thread functions
+    PyObject* thread = PyImport_ImportModule("_thread");
+    PyObject* get_ident = PyObject_GetAttrString(thread, "get_ident");
+    PyObject* ident = PyObject_CallObject(get_ident, 0);
+    Py_DECREF(get_ident);
+    threadid = PyLong_AsLong(ident);
+    Py_DECREF(ident);
+
     // run and generate errors etc
     messages.clear();
     PyRun_SimpleString(line.toStdString().c_str());
@@ -117,9 +126,19 @@ void PythonEmbed::runline(QString line)
         PyObject_CallFunction(static_cast<PyObject*>(clear), NULL);
     }
     PyGILState_Release(gstate);
+    threadid=-1;
 }
 
 void
 PythonEmbed::cancel()
 {
+    if (chart!=NULL && threadid != -1) {
+        PyGILState_STATE gstate;
+        gstate = PyGILState_Ensure();
+
+        // raise an exception to cancel the execution
+        PyThreadState_SetAsyncExc(threadid, PyExc_KeyboardInterrupt);
+
+        PyGILState_Release(gstate);
+    }
 }
diff --git a/src/Python/PythonEmbed.h b/src/Python/PythonEmbed.h
index 9cfee5800..bb3a7635b 100644
--- a/src/Python/PythonEmbed.h
+++ b/src/Python/PythonEmbed.h
@@ -64,6 +64,7 @@ class PythonEmbed {
     bool cancelled;
 
     bool loaded;
+    long threadid;
 };
 
 #endif