lib/android/dalvik.nit

   1 # This file is part of NIT (http://www.nitlanguage.org).
   2 #
   3 # Copyright 2012-2014 Alexis Laferrière <alexis.laf@xymus.net>
   4 #
   5 # Licensed under the Apache License, Version 2.0 (the "License");
   6 # you may not use this file except in compliance with the License.
   7 # You may obtain a copy of the License at
   8 #
   9 #     http://www.apache.org/licenses/LICENSE-2.0
  10 #
  11 # Unless required by applicable law or agreed to in writing, software
  12 # distributed under the License is distributed on an "AS IS" BASIS,
  13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14 # See the License for the specific language governing permissions and
  15 # limitations under the License.
  16
  17 # Java related services specific to Android and its Dalvik VM
  18 module dalvik
  19
  20 import activities
  21
  22 redef class App
  23         # Main Java Activity of this application
  24         #
  25         # Require: A Nit activity is currently running.
  26         fun native_activity: NativeActivity is abstract
  27
  28         # Current reference context, either an activity or a service
  29         fun native_context: NativeContext do return native_activity
  30 end
  31
  32 extern class JavaClassLoader in "Java" `{java.lang.ClassLoader`}
  33         super JavaObject
  34 end
  35
  36 redef class Sys
  37         # We cannot create a JVM on Android
  38         #
  39         # This method is not reachable on this platform anyway.
  40         # `Sys::jvm` is implemented by the main activity modules.
  41         redef fun create_default_jvm do abort
  42
  43         redef fun jni_env do return jvm.attach_current_thread
  44
  45         private var class_loader: nullable JavaObject = null
  46         private var class_loader_method: nullable JMethodID = null
  47         redef fun load_jclass(name)
  48         do
  49                 var class_loader = self.class_loader
  50                 if class_loader == null then
  51                         find_class_loader app.native_context
  52                         class_loader = self.class_loader
  53                         assert class_loader != null
  54                 end
  55
  56                 var class_loader_method = self.class_loader_method
  57                 assert class_loader_method != null
  58
  59                 return load_jclass_intern(class_loader, class_loader_method, name)
  60         end
  61
  62         private fun find_class_loader(native_context: NativeContext) import jni_env, class_loader=, JavaObject.as nullable, class_loader_method=, JMethodID.as nullable `{
  63                 JNIEnv *env = Sys_jni_env(self);
  64
  65                 // Retrieve main activity
  66                 jclass class_context = (*env)->GetObjectClass(env, native_context);
  67                 if (class_context == NULL) {
  68                         __android_log_print(ANDROID_LOG_ERROR, "Nit", "Failed to retrieve activity class");
  69                         (*env)->ExceptionDescribe(env);
  70                         exit(1);
  71                 }
  72
  73                 jmethodID class_activity_getClassLoader = (*env)->GetMethodID(env, class_context, "getClassLoader", "()Ljava/lang/ClassLoader;");
  74                 if (class_activity_getClassLoader == NULL) {
  75                         __android_log_print(ANDROID_LOG_ERROR, "Nit", "Failed to retrieve 'getClassLoader' method");
  76                         (*env)->ExceptionDescribe(env);
  77                         exit(1);
  78                 }
  79
  80                 // Call activity.getClassLoader
  81                 jobject instance_class_loader = (*env)->CallObjectMethod(env, native_context, class_activity_getClassLoader);
  82                 if (instance_class_loader == NULL) {
  83                         __android_log_print(ANDROID_LOG_ERROR, "Nit", "Failed to retrieve class loader instance");
  84                         (*env)->ExceptionDescribe(env);
  85                         exit(1);
  86                 }
  87
  88                 jclass class_class_loader = (*env)->GetObjectClass(env, instance_class_loader);
  89                 if (class_class_loader == NULL) {
  90                         __android_log_print(ANDROID_LOG_ERROR, "Nit", "Failed to retrieve class of class loader");
  91                         (*env)->ExceptionDescribe(env);
  92                         exit(1);
  93                 }
  94
  95                 // Get the method ClassLoader.findClass
  96                 jmethodID class_class_loader_findClass = (*env)->GetMethodID(env, class_class_loader, "findClass", "(Ljava/lang/String;)Ljava/lang/Class;");
  97                 if (class_class_loader_findClass == NULL) {
  98                         __android_log_print(ANDROID_LOG_ERROR, "Nit", "Failed to retrieve 'findClass' method");
  99                         (*env)->ExceptionDescribe(env);
 100                         exit(1);
 101                 }
 102
 103                 // Return the values to Nit
 104                 Sys_class_loader__assign(self, JavaObject_as_nullable((*env)->NewGlobalRef(env, instance_class_loader)));
 105                 Sys_class_loader_method__assign(self, JMethodID_as_nullable(class_class_loader_findClass));
 106
 107                 // Clean up
 108                 (*env)->DeleteLocalRef(env, class_context);
 109                 (*env)->DeleteLocalRef(env, instance_class_loader);
 110                 (*env)->DeleteLocalRef(env, class_class_loader);
 111         `}
 112
 113         private fun load_jclass_intern(instance_class_loader: JavaObject, class_loader_findClass: JMethodID, name: NativeString): JClass import jni_env `{
 114                 JNIEnv *env = Sys_jni_env(self);
 115                 jobject class_name = (*env)->NewStringUTF(env, name);
 116
 117                 jclass java_class = (*env)->CallObjectMethod(env, instance_class_loader, class_loader_findClass, class_name);
 118                 if (java_class == NULL) {
 119                         __android_log_print(ANDROID_LOG_ERROR, "Nit", "Failed loading targeted class");
 120                         (*env)->ExceptionDescribe(env);
 121                         exit(1);
 122                 }
 123
 124                 (*env)->DeleteLocalRef(env, class_name);
 125
 126                 return java_class;
 127         `}
 128 end