java: Updated gpio.c to use JNI functions set in mraa_lang_func

This is a re-design of commit 0041801. mraa_lang_func_t structure has been
added (similar in design to mraa_adv_func_t) that points to JNI functions
implemented in src/java/mraajni.c. Functions are set by libmraajava.so,
see wrapper entry in src/java/mraajava.i. As gpio.c now uses these
functions, language specific #ifdef code has been removed as JNI code
is only called if functions are defined (i.e. not NULL)

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

include/java/mraajni.h

@@ -1,6 +1,6 @@
 /*
- * Author: Henry bruce <henry.bruce@intel.com>
+ * Author: Henry Bruce <henry.bruce@intel.com>
- * Copyright (c) 2014 Intel Corporation.
+ * Copyright (c) 2014-2016 Intel Corporation.
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
@@ -32,7 +32,7 @@ extern "C" {
 #include "mraa/types.h"
 
 void mraa_java_set_jvm(JavaVM* vm);
-void mraa_java_isr_callback(void *args);
+void mraa_java_isr_callback(void* args);
 mraa_result_t mraa_java_attach_thread();
 void mraa_java_detach_thread();
 void* mraa_java_create_global_ref(void* args);
@@ -41,4 +41,3 @@ void mraa_java_delete_global_ref(void* ref);
 #ifdef __cplusplus
 }
 #endif
-

include/mraa_internal.h

@@ -34,9 +34,11 @@ extern "C" {
 #include "common.h"
 #include "mraa_internal_types.h"
 #include "mraa_adv_func.h"
+#include "mraa_lang_func.h"
 
 extern mraa_board_t* plat;
 extern mraa_iio_info_t* plat_iio;
+extern mraa_lang_func_t* lang_func;
 
 /**
  * Takes in pin information and sets up the multiplexors.

include/mraa_lang_func.h

@@ -0,0 +1,35 @@
+/*
+ * 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
+
+typedef struct {
+    void (*python_isr)(void (*isr)(void*), void* isr_args);
+	void (*java_isr_callback)(void *args);
+	mraa_result_t (*java_attach_thread)();
+	void (*java_detach_thread)();
+	void* (*java_create_global_ref)(void* args);
+	void (*java_delete_global_ref)(void* ref);
+
+} mraa_lang_func_t;

src/CMakeLists.txt

@@ -175,15 +175,6 @@ if (BUILDSWIG)
       add_subdirectory (python)
     endif ()
     if (BUILDSWIGJAVA)
-      FIND_PACKAGE (JNI REQUIRED)
-      include_directories (
-        ${JAVA_INCLUDE_PATH}
-        ${JAVA_INCLUDE_PATH2}
-        ${CMAKE_CURRENT_SOURCE_DIR}/..
-      )
-      set (mraa_LIB_SRCS ${mraa_LIB_SRCS} ${CMAKE_CURRENT_SOURCE_DIR}/java/mraajni.c)
-      set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fpermissive -DJAVACALLBACK")
-      set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -DJAVACALLBACK")
       add_subdirectory (java)
     endif ()
     if (BUILDSWIGNODE)

src/gpio/gpio.c

@@ -24,9 +24,6 @@
  */
 #include "gpio.h"
 #include "mraa_internal.h"
-#if defined(SWIGJAVA) || defined(JAVACALLBACK)
-#include "java/mraajni.h"
-#endif
 
 #include <stdlib.h>
 #include <fcntl.h>
@@ -268,15 +265,15 @@ mraa_gpio_interrupt_handler(void* arg)
 
     dev->isr_value_fp = fp;
 
-#if defined(SWIGJAVA) || defined(JAVACALLBACK)
+    if (lang_func->java_attach_thread != NULL) {
-    if(dev->isr == mraa_java_isr_callback) {
+        if (dev->isr == lang_func->java_isr_callback) {
-        if (mraa_java_attach_thread() != MRAA_SUCCESS) {
+            if (lang_func->java_attach_thread() != MRAA_SUCCESS) {
-            close(dev->isr_value_fp);
+                close(dev->isr_value_fp);
-            dev->isr_value_fp = -1;
+                dev->isr_value_fp = -1;
-            return NULL;
+                return NULL;
+            }
         }
     }
-#endif
 
     for (;;) {
         if (IS_FUNC_DEFINED(dev, gpio_wait_interrupt_replace)) {
@@ -292,71 +289,11 @@ mraa_gpio_interrupt_handler(void* arg)
 #ifdef HAVE_PTHREAD_CANCEL
             pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, NULL);
 #endif
-#ifdef SWIGPYTHON
+            if (lang_func->python_isr != NULL) {
-            // In order to call a python object (all python functions are objects) we
+                lang_func->python_isr(dev->isr, dev->isr_args);
-            // 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
-            PyGILState_STATE gilstate = PyGILState_Ensure();
-            PyObject* arglist;
-            PyObject* ret;
-            arglist = Py_BuildValue("(O)", dev->isr_args);
-            if (arglist == NULL) {
-                syslog(LOG_ERR, "gpio: Py_BuildValue NULL");
             } else {
-                ret = PyEval_CallObject((PyObject*) dev->isr, arglist);
+                dev->isr(dev->isr_args);
-                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);
-#else
-            dev->isr(dev->isr_args);
-#endif
 #ifdef HAVE_PTHREAD_CANCEL
             pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
 #endif
@@ -369,12 +306,14 @@ mraa_gpio_interrupt_handler(void* arg)
                 close(dev->isr_value_fp);
                 dev->isr_value_fp = -1;
             }
-#if defined(SWIGJAVA) || defined(JAVACALLBACK)
+
-            if(dev->isr == mraa_java_isr_callback) {
+            if (lang_func->java_detach_thread != NULL && lang_func->java_delete_global_ref != NULL) {
-                mraa_java_delete_global_ref(dev->isr_args);
+                if (dev->isr == lang_func->java_isr_callback) {
-                mraa_java_detach_thread();
+                    lang_func->java_delete_global_ref(dev->isr_args);
+                    lang_func->java_detach_thread();
+                }
             }
-#endif
+
             return NULL;
         }
     }
@@ -442,13 +381,15 @@ mraa_gpio_isr(mraa_gpio_context dev, mraa_gpio_edge_t mode, void (*fptr)(void*),
     }
 
     dev->isr = fptr;
-#if defined(SWIGJAVA) || defined(JAVACALLBACK)
+
-    /* Most UPM sensors use the C API, the global ref must be created here. */
+    /* Most UPM sensors use the C API, the Java global ref must be created here. */
     /* The reason for checking the callback function is internal callbacks. */
-    if (fptr == mraa_java_isr_callback) {
+    if (lang_func->java_create_global_ref != NULL) {
-        args = mraa_java_create_global_ref(args);
+        if (dev->isr == lang_func->java_isr_callback) {
+            args = lang_func->java_create_global_ref(args);
+        }
     }
-#endif
+
     dev->isr_args = args;
     pthread_create(&dev->thread_id, NULL, mraa_gpio_interrupt_handler, (void*) dev);
 

src/java/CMakeLists.txt

@@ -1,3 +1,10 @@
+FIND_PACKAGE (JNI REQUIRED)
+include_directories (
+  ${JAVA_INCLUDE_PATH}
+  ${JAVA_INCLUDE_PATH2}
+  ${CMAKE_CURRENT_SOURCE_DIR}/..
+)
+
 # SWIG treats SWIG_FLAGS as a list and not a string so semicolon seperation is required
 set_source_files_properties (mraajava.i PROPERTIES SWIG_FLAGS ";-package;mraa;-I${CMAKE_BINARY_DIR}/src")
 set_source_files_properties (mraajava.i PROPERTIES CPLUSPLUS ON)
@@ -17,7 +24,7 @@ else ()
   set (JAR $ENV{JAVA_HOME_NATIVE}/bin/jar)
 endif ()
 
-swig_add_module (mraajava java mraajava.i)
+swig_add_module (mraajava java mraajava.i mraajni.c)
 swig_link_libraries (mraajava ${JAVA_LIBRARIES} mraa)
 
 add_custom_command (TARGET mraajava

src/java/mraajava.i

@@ -66,12 +66,21 @@ class Spi;
 
 %wrapper %{
     #include "java/mraajni.h"
+    #include "mraa_lang_func.h"
+    extern mraa_lang_func_t* lang_func;
 
     jint JNI_OnLoad(JavaVM *vm, void *reserved) {
-        /* initialize mraa */
+        /* initialize mraa and set jni functions */
-        mraa_java_set_jvm(vm);
+        mraa_result_t res = mraa_init();
-        mraa_init();
+        if (res == MRAA_SUCCESS || res == MRAA_ERROR_PLATFORM_ALREADY_INITIALISED) {
-        return JNI_VERSION_1_6;
+            mraa_java_set_jvm(vm);
+            lang_func->java_isr_callback = &mraa_java_isr_callback;
+            lang_func->java_attach_thread  = &mraa_java_attach_thread;
+            lang_func->java_detach_thread = &mraa_java_detach_thread;
+            lang_func->java_create_global_ref = &mraa_java_create_global_ref;
+            lang_func->java_delete_global_ref = &mraa_java_delete_global_ref;
+        }
+        return JNI_VERSION_1_8;
     }
 %}
 

src/java/mraajni.c

@@ -41,11 +41,11 @@ static void
 mraa_java_make_env_key(void)
 {
     if (globVM != NULL) {
-        JNIEnv *jenv;
+        JNIEnv* jenv;
-        (*globVM)->GetEnv(globVM, (void **)&jenv, JNI_VERSION_1_8);
+        (*globVM)->GetEnv(globVM, (void**) &jenv, JNI_VERSION_1_8);
         jclass rcls = (*jenv)->FindClass(jenv, "java/lang/Runnable");
         jmethodID runm = (*jenv)->GetMethodID(jenv, rcls, "run", "()V");
-        runGlobal = (jmethodID)(*jenv)->NewGlobalRef(jenv, (jobject)runm);
+        runGlobal = (jmethodID)(*jenv)->NewGlobalRef(jenv, (jobject) runm);
         pthread_key_create(&env_key, NULL);
     }
 }
@@ -53,16 +53,16 @@ mraa_java_make_env_key(void)
 void
 mraa_java_isr_callback(void* data)
 {
-    JNIEnv *jenv = (JNIEnv *) pthread_getspecific(env_key);
+    JNIEnv* jenv = (JNIEnv*) pthread_getspecific(env_key);
-    (*jenv)->CallVoidMethod(jenv, (jobject)data, runGlobal);
+    (*jenv)->CallVoidMethod(jenv, (jobject) data, runGlobal);
 }
 
 mraa_result_t
 mraa_java_attach_thread()
 {
     if (globVM != NULL) {
-        JNIEnv *jenv;
+        JNIEnv* jenv;
-        jint err = (*globVM)->AttachCurrentThreadAsDaemon(globVM, (void **)&jenv, NULL);
+        jint err = (*globVM)->AttachCurrentThreadAsDaemon(globVM, (void**) &jenv, NULL);
         if (err == JNI_OK) {
             pthread_once(&env_key_init, mraa_java_make_env_key);
             pthread_setspecific(env_key, jenv);
@@ -83,21 +83,20 @@ void*
 mraa_java_create_global_ref(void* args)
 {
     if (globVM != NULL) {
-        JNIEnv *jenv;
+        JNIEnv* jenv;
-        (*globVM)->GetEnv(globVM, (void **)&jenv, JNI_VERSION_1_8);
+        (*globVM)->GetEnv(globVM, (void**) &jenv, JNI_VERSION_1_8);
         jobject grunnable = (*jenv)->NewGlobalRef(jenv, (jobject) args);
-        return (void *)grunnable;
+        return (void*) grunnable;
     } else
         return NULL;
 }
 
 void
-mraa_java_delete_global_ref(void *ref)
+mraa_java_delete_global_ref(void* ref)
 {
     if (globVM != NULL) {
-        JNIEnv *jenv;
+        JNIEnv* jenv;
-        (*globVM)->GetEnv(globVM, (void **)&jenv, JNI_VERSION_1_8);
+        (*globVM)->GetEnv(globVM, (void**) &jenv, JNI_VERSION_1_8);
-        (*jenv)->DeleteGlobalRef(jenv, (jobject)ref);
+        (*jenv)->DeleteGlobalRef(jenv, (jobject) ref);
     }
 }
-

src/mraa.c

@@ -48,6 +48,7 @@
 #define IIO_DEVICE_WILDCARD "iio:device*"
 mraa_board_t* plat = NULL;
 mraa_iio_info_t* plat_iio = NULL;
+mraa_lang_func_t* lang_func = NULL;
 
 static char* platform_name = NULL;
 static char* platform_long_name = NULL;
@@ -163,6 +164,8 @@ mraa_init()
         }
     }
 
+    lang_func = (mraa_lang_func_t*) calloc(1, sizeof(mraa_lang_func_t));
+
     syslog(LOG_NOTICE, "libmraa initialised for platform '%s' of type %d", mraa_get_platform_name(), mraa_get_platform_type());
     return MRAA_SUCCESS;
 }