Merge pull request #2 from DataDog/remicalixte/high-level-layer

High Level Layer

README.md

@@ -0,0 +1,27 @@
+go-python3
+==========
+
+Golang bindings for the C-API of CPython-3.
+
+This package provides a ``go`` package named "python" under which most of the
+``PyXYZ`` functions and macros of the public C-API of CPython have been
+exposed. Theoretically, you should be able use https://docs.python.org/3/c-api
+and know what to type in your ``go`` program.
+
+API
+---
+
+Some functions mix go code and call to Python function. Those functions will
+return and `int` and `error` type. The `int` represent the Python result code
+and the `error` represent any issue from the Go layer.
+
+Example:
+
+`func PyRun_AnyFile(filename string)` open `filename` and then call CPython API
+function `int PyRun_AnyFile(FILE *fp, const char *filename)`.
+
+Therefore its signature is `func PyRun_AnyFile(filename string) (int, error)`,
+the `int` represent the error code from the CPython `PyRun_AnyFile` function
+and error will be set if we failed to open `filename`.
+
+If an error is raise before calling th CPython function `int` default to `-1`.

high_level_layer.go

@@ -0,0 +1,59 @@
+package python3
+
+/*
+#cgo pkg-config: python3
+#include "Python.h"
+*/
+import "C"
+import (
+	"unsafe"
+)
+
+//Py_Main : https://docs.python.org/3/c-api/veryhigh.html?highlight=pycompilerflags#c.Py_Main
+// "error" will be set if we fail to call "Py_DecodeLocale" on every "args".
+func Py_Main(args []string) (int, error) {
+	argc := C.int(len(args))
+	argv := make([]*C.wchar_t, argc, argc)
+	for i, arg := range args {
+		carg := C.CString(arg)
+		defer C.free(unsafe.Pointer(carg))
+
+		warg := C.Py_DecodeLocale(carg, nil)
+		if warg == nil {
+			return -1, fmt.Errorf("fail to call Py_DecodeLocale on '%s'", arg)
+		}
+		// Py_DecodeLocale requires a call to PyMem_RawFree to free the memory
+		defer C.PyMem_RawFree(unsafe.Pointer(warg))
+		argv[i] = warg
+	}
+
+	return int(C.Py_Main(argc, (**C.wchar_t)(unsafe.Pointer(&argv[0])))), nil
+}
+
+//PyRun_AnyFile : https://docs.python.org/3/c-api/veryhigh.html?highlight=pycompilerflags#c.PyRun_AnyFile
+// "error" will be set if we fail to open "filename".
+func PyRun_AnyFile(filename string) (int, error) {
+	cfilename := C.CString(filename)
+	defer C.free(unsafe.Pointer(cfilename))
+
+	mode := C.CString("r")
+	defer C.free(unsafe.Pointer(mode))
+
+	cfile, err := C.fopen(cfilename, mode)
+	if err != nil {
+		return -1, fmt.Errorf("fail to open '%s': %s", filename, err)
+	}
+	defer C.fclose(cfile)
+
+	// C.PyRun_AnyFile is a macro, using C.PyRun_AnyFileFlags instead
+	return int(C.PyRun_AnyFileFlags(cfile, cfilename, nil)), 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)
+	defer C.free(unsafe.Pointer(ccommand))
+
+	// C.PyRun_SimpleString is a macro, using C.PyRun_SimpleStringFlags instead
+	return int(C.PyRun_SimpleStringFlags(ccommand, nil))
+}