get rid of pkg-config, migrate to Python 3.9 and add a few other opti…

…ons in high_level_layer.go

dict.go

@@ -138,5 +138,6 @@ func PyDict_Next(p *PyObject, ppos *int, pkey, pvalue **PyObject) bool {
 
 //PyDict_ClearFreeList : https://docs.python.org/3/c-api/dict.html#c.PyDict_ClearFreeList
 func PyDict_ClearFreeList() int {
-	return int(C.PyDict_ClearFreeList())
+	// PyDict_ClearFreeList removed in Python 3.9, use PyGC_Collect instead.
+	return int(C.PyGC_Collect())
 }

float.go

@@ -59,5 +59,6 @@ func PyFloat_GetMin() float64 {
 
 //PyFloat_ClearFreeList : https://docs.python.org/3/c-api/float.html#c.PyFloat_ClearFreeList
 func PyFloat_ClearFreeList() int {
-	return int(C.PyFloat_ClearFreeList())
+	// PyFloat_ClearFreeList removed in Python 3.9, use PyGC_Collect instead.
+	return int(C.PyGC_Collect())
 }

high_level_layer.go

@@ -8,12 +8,13 @@ Copyright 2018 Datadog, Inc.
 package python3
 
 /*
-#cgo pkg-config: python3
 #include "Python.h"
 */
 import "C"
 import (
+	"errors"
 	"fmt"
+	"strings"
 	"unsafe"
 )
 
@@ -57,6 +58,46 @@ func PyRun_AnyFile(filename string) (int, error) {
 	return int(C.PyRun_AnyFileFlags(cfile, cfilename, nil)), nil
 }
 
+//PyRun_SimpleFile : https://docs.python.org/3.9/c-api/veryhigh.html?highlight=pycompilerflags#c.PyRun_SimpleFile
+// "error" will be set if we fail to open "filename".
+func PyRun_SimpleFile(filename string) (int, error) {
+	cfilename := C.CString(filename)
+	defer C.free(unsafe.Pointer(cfilename))
+
+	mode := C.CString("rb")
+	defer C.free(unsafe.Pointer(mode))
+
+	cfile, err := C.fopen(cfilename, mode)
+	if err != nil {
+		return -1, fmt.Errorf("fail to open '%s': %v", filename, err)
+	}
+	defer C.fclose(cfile)
+
+	// For now we have an issue (seg fault) with this function,
+	// so let's read the input file ourselves and execute as
+	// a string command instead.
+	//ret := C.PyRun_SimpleFileExFlags(cfile, cfilename, 1, nil)
+
+
+	C.fseek(cfile , 0 , C.SEEK_END);
+	lSize := C.ftell(cfile);
+	C.rewind(cfile);
+
+	cbuffer := C.CString(strings.Repeat("0", int(lSize)))
+	if cbuffer == nil {
+		return 1, errors.New("memory alloc fails")
+	};
+	defer C.free(unsafe.Pointer(cbuffer))
+
+	if 1!=C.fread( unsafe.Pointer(cbuffer) , C.ulonglong(lSize), 1 , cfile) {
+		return 1, errors.New("entire read fails")
+	}
+
+	ret := C.PyRun_SimpleStringFlags(cbuffer, nil)
+
+	return int(ret), nil
+}
+
 //PyRun_SimpleString : https://docs.python.org/3/c-api/veryhigh.html?highlight=pycompilerflags#c.PyRun_SimpleString
 func PyRun_SimpleString(command string) int {
 	ccommand := C.CString(command)

list.go

@@ -84,5 +84,6 @@ func PyList_AsTuple(list *PyObject) *PyObject {
 
 //PyList_ClearFreeList : https://docs.python.org/3/c-api/list.html#c.PyList_ClearFreeList
 func PyList_ClearFreeList() int {
-	return int(C.PyList_ClearFreeList())
+	// PyList_ClearFreeList removed in Python 3.9, use PyGC_Collect instead.
+	return int(C.PyGC_Collect())
 }

thread.go

@@ -18,15 +18,19 @@ type PyThreadState C.PyThreadState
 //PyGILState is an opaque “handle” to the thread state when PyGILState_Ensure() was called, and must be passed to PyGILState_Release() to ensure Python is left in the same state
 type PyGILState C.PyGILState_STATE
 
+/* Deprecated since Python 3.9, this function does nothing.
 //PyEval_InitThreads : https://docs.python.org/3/c-api/init.html#c.PyEval_InitThreads
 func PyEval_InitThreads() {
 	C.PyEval_InitThreads()
 }
+*/
 
+/* Deprecated since Python 3.9, this function does nothing.
 //PyEval_ThreadsInitialized : https://docs.python.org/3/c-api/init.html#c.PyEval_ThreadsInitialized
 func PyEval_ThreadsInitialized() bool {
 	return C.PyEval_ThreadsInitialized() != 0
 }
+*/
 
 //PyEval_SaveThread : https://docs.python.org/3/c-api/init.html#c.PyEval_SaveThread
 func PyEval_SaveThread() *PyThreadState {

thread_test.go

@@ -19,7 +19,7 @@ func TestThreadInitialization(t *testing.T) {
 
 func TestGIL(t *testing.T) {
 	Py_Initialize()
-	PyEval_InitThreads()
+	//PyEval_InitThreads()
 
 	gil := PyGILState_Ensure()
 
@@ -30,7 +30,7 @@ func TestGIL(t *testing.T) {
 
 func TestThreadState(t *testing.T) {
 	Py_Initialize()
-	PyEval_InitThreads()
+	//PyEval_InitThreads()
 
 	threadState := PyGILState_GetThisThreadState()
 
@@ -45,7 +45,7 @@ func TestThreadState(t *testing.T) {
 
 func TestThreadSaveRestore(t *testing.T) {
 	Py_Initialize()
-	PyEval_InitThreads()
+	//PyEval_InitThreads()
 
 	threadState := PyEval_SaveThread()