python: Python native library now links to libmraa.so

Implementation is similar to approach taken for Java.

Signed-off-by: Henry Bruce <henry.bruce@intel.com>
Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

api/mraa/gpio.h

@@ -40,10 +40,6 @@
 extern "C" {
 #endif
 
-#ifdef SWIGPYTHON
-#include <Python.h>
-#endif
-
 #include <stdio.h>
 #include <pthread.h>
 #include "common.h"

include/python/mraapy.h

@@ -0,0 +1,27 @@
+/*
+ * Author: Henry Bruce <henry.bruce@intel.com>
+ * Copyright (c) 2016 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#pragma once
+
+void mraa_python_isr(void (*isr)(void*), void* isr_args);

src/mraa.c

@@ -99,13 +99,6 @@ mraa_init()
     syslog(LOG_NOTICE, "libmraa version %s initialised by user '%s' with EUID %d",
            mraa_get_version(), (proc_user != NULL) ? proc_user->pw_name : "<unknown>", proc_euid);
 
-#ifdef SWIGPYTHON
-    // Initialise python threads, this allows use to grab the GIL when we are
-    // required to do so
-    Py_InitializeEx(0);
-    PyEval_InitThreads();
-#endif
-
     mraa_platform_t platform_type;
 #if defined(X86PLAT)
     // Use runtime x86 platform detection

src/python/CMakeLists.txt

@@ -1,7 +1,5 @@
 find_package (PythonLibs ${PYTHONBUILD_VERSION} REQUIRED)
 
-INCLUDE_DIRECTORIES(${PYTHON_INCLUDE_PATH})
-
 include_directories(
   ${CMAKE_CURRENT_SOURCE_DIR}/..
   ${PYTHON_INCLUDE_DIRS}
@@ -9,8 +7,8 @@ include_directories(
 
 set_source_files_properties (mraa.i PROPERTIES CPLUSPLUS ON)
 set_source_files_properties (mraa.i PROPERTIES SWIG_FLAGS "-I${CMAKE_BINARY_DIR}/src")
-swig_add_module (python-mraa python mraa.i ${mraa_LIB_SRCS})
-swig_link_libraries (python-mraa ${PYTHON_LIBRARIES} ${mraa_LIBS})
+swig_add_module (python-mraa python mraa.i mraapy.c)
+swig_link_libraries (python-mraa ${PYTHON_LIBRARIES} mraa)
 
 if (DOXYGEN_FOUND)
   foreach (_file ${DOCCLASSES})

src/python/mraa.i

@@ -149,6 +149,17 @@ class Spi;
 %include ../mraa.i
 
 %init %{
-    //Adding mraa_init() to the module initialisation process
-    mraa_init();
+    #include "python/mraapy.h"
+    #include "mraa_lang_func.h"
+    extern mraa_lang_func_t* lang_func;
+    // Initialise python threads, this allows use to grab the GIL when we are
+    // required to do so
+    Py_InitializeEx(0);
+    PyEval_InitThreads();
+    // Add mraa_init() to the module initialisation process and set isr function
+    mraa_result_t res = mraa_init();
+    if (res == MRAA_SUCCESS || res == MRAA_ERROR_PLATFORM_ALREADY_INITIALISED) {
+        lang_func->python_isr = &mraa_python_isr;
+    }
+
 %}

src/python/mraapy.c

@@ -0,0 +1,91 @@
+/*
+ * Author: Henry Bruce <henry.bruce@intel.com>
+ * Copyright (c) 2016 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <syslog.h>
+#include <Python.h>
+#include "python/mraapy.h"
+
+
+// In order to call a python object (all python functions are objects) we
+// need to aquire the GIL (Global Interpreter Lock). This may not always be
+// necessary but especially if doing IO (like print()) python will segfault
+// if we do not hold a lock on the GIL
+void
+mraa_python_isr(void (*isr)(void*), void* isr_args)
+{
+
+    PyGILState_STATE gilstate = PyGILState_Ensure();
+    PyObject* arglist;
+    PyObject* ret;
+    arglist = Py_BuildValue("(O)", isr_args);
+    if (arglist == NULL) {
+        syslog(LOG_ERR, "gpio: Py_BuildValue NULL");
+    } else {
+        ret = PyEval_CallObject((PyObject*) isr, arglist);
+        if (ret == NULL) {
+            syslog(LOG_ERR, "gpio: PyEval_CallObject failed");
+            PyObject *pvalue, *ptype, *ptraceback;
+            PyObject *pvalue_pystr, *ptype_pystr, *ptraceback_pystr;
+            char *pvalue_cstr, *ptype_cstr, *ptraceback_cstr;
+            PyErr_Fetch(&pvalue, &ptype, &ptraceback);
+            pvalue_pystr = PyObject_Str(pvalue);
+            ptype_pystr = PyObject_Str(ptype);
+            ptraceback_pystr = PyObject_Str(ptraceback);
+// Python2
+#if PY_VERSION_HEX < 0x03000000
+            pvalue_cstr = PyString_AsString(pvalue_pystr);
+            ptype_cstr = PyString_AsString(ptype_pystr);
+            ptraceback_cstr = PyString_AsString(ptraceback_pystr);
+// Python 3 and up
+#elif PY_VERSION_HEX >= 0x03000000
+            // In Python 3 we need one extra conversion
+            PyObject *pvalue_ustr, *ptype_ustr, *ptraceback_ustr;
+            pvalue_ustr = PyUnicode_AsUTF8String(pvalue_pystr);
+            pvalue_cstr = PyBytes_AsString(pvalue_ustr);
+            ptype_ustr = PyUnicode_AsUTF8String(ptype_pystr);
+            ptype_cstr = PyBytes_AsString(ptype_ustr);
+            ptraceback_ustr = PyUnicode_AsUTF8String(ptraceback_pystr);
+            ptraceback_cstr = PyBytes_AsString(ptraceback_ustr);
+#endif // PY_VERSION_HEX
+            syslog(LOG_ERR, "gpio: the error was %s:%s:%s", pvalue_cstr, ptype_cstr, ptraceback_cstr);
+            Py_XDECREF(pvalue);
+            Py_XDECREF(ptype);
+            Py_XDECREF(ptraceback);
+            Py_XDECREF(pvalue_pystr);
+            Py_XDECREF(ptype_pystr);
+            Py_XDECREF(ptraceback_pystr);
+// Python 3 and up
+#if PY_VERSION_HEX >= 0x03000000
+            Py_XDECREF(pvalue_ustr);
+            Py_XDECREF(ptype_ustr);
+            Py_XDECREF(ptraceback_ustr);
+#endif // PY_VERSION_HEX
+        } else {
+            Py_DECREF(ret);
+        }
+        Py_DECREF(arglist);
+    }
+
+    PyGILState_Release(gilstate);
+}