Android: Don't share the JNI environment across threads, but obtain it the

correct way

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@29569 a1c6a512-1295-4272-9138-f99709370657

firmware/target/hosted/android/button-android.c

@@ -29,7 +29,6 @@
 #include "system.h"
 #include "touchscreen.h"
 
-extern JNIEnv *env_ptr;
 static int last_y, last_x;
 static int last_btns;
 

firmware/target/hosted/android/lcd-android.c

@@ -28,7 +28,6 @@
 #include "lcd.h"
 #include "button.h"
 
-extern JNIEnv *env_ptr;
 extern jobject RockboxService_instance;
 
 static jobject RockboxFramebuffer_instance;
@@ -94,6 +93,8 @@ void connect_with_java(JNIEnv* env, jobject fb_instance)
 
 void lcd_deinit(void)
 {
+    JNIEnv *env_ptr = getJavaEnvironment();
+
     (*env_ptr)->DeleteGlobalRef(env_ptr, RockboxFramebuffer_instance);
     (*env_ptr)->DeleteGlobalRef(env_ptr, native_buffer);
 }
@@ -107,6 +108,8 @@ void lcd_init_device(void)
 
 void lcd_update(void)
 {
+    JNIEnv *env_ptr = getJavaEnvironment();
+
     if (display_on)
         (*env_ptr)->CallVoidMethod(env_ptr, RockboxFramebuffer_instance,
                                    java_lcd_update);
@@ -114,6 +117,8 @@ void lcd_update(void)
 
 void lcd_update_rect(int x, int y, int width, int height)
 {
+    JNIEnv *env_ptr = getJavaEnvironment();
+
     if (display_on)
         (*env_ptr)->CallVoidMethod(env_ptr, RockboxFramebuffer_instance,
                                    java_lcd_update_rect, x, y, width, height);

firmware/target/hosted/android/pcm-android.c

@@ -25,8 +25,6 @@
 #include "debug.h"
 #include "pcm.h"
 
-extern JNIEnv *env_ptr;
-
 /* infos about our pcm chunks */
 static size_t  pcm_data_size;
 static char   *pcm_data_start;
@@ -117,6 +115,8 @@ void pcm_play_dma_start(const void *addr, size_t size)
 
 void pcm_play_dma_stop(void)
 {
+    JNIEnv *env_ptr = getJavaEnvironment();
+
     (*env_ptr)->CallVoidMethod(env_ptr,
                                RockboxPCM_instance,
                                stop_method);
@@ -124,6 +124,8 @@ void pcm_play_dma_stop(void)
 
 void pcm_play_dma_pause(bool pause)
 {
+    JNIEnv *env_ptr = getJavaEnvironment();
+
     (*env_ptr)->CallVoidMethod(env_ptr,
                                RockboxPCM_instance,
                                play_pause_method,
@@ -152,6 +154,7 @@ void pcm_play_dma_init(void)
      * Luckily we only reference the PCM object from here, so it's safe (and
      * clean) to allocate it here
      **/
+    JNIEnv *env_ptr = getJavaEnvironment();
     JNIEnv e = *env_ptr;
     /* get the class and its constructor */
     jclass RockboxPCM_class = e->FindClass(env_ptr, "org/rockbox/RockboxPCM");
@@ -169,6 +172,8 @@ void pcm_play_dma_init(void)
 
 void pcm_deinit(void)
 {
+    JNIEnv *env_ptr = getJavaEnvironment();
+
     (*env_ptr)->DeleteGlobalRef(env_ptr, RockboxPCM_instance);
 }
 
@@ -178,5 +183,7 @@ void pcm_postinit(void)
 
 void pcm_set_mixer_volume(int volume)
 {
+    JNIEnv *env_ptr = getJavaEnvironment();
+
     (*env_ptr)->CallVoidMethod(env_ptr, RockboxPCM_instance, set_volume_method, volume);
 }

firmware/target/hosted/android/powermgmt-android.c

@@ -23,8 +23,8 @@
 #include <jni.h>
 #include <stdbool.h>
 #include "config.h"
+#include "system.h"
 
-extern JNIEnv *env_ptr;
 extern jclass  RockboxService_class;
 extern jobject RockboxService_instance;
 
@@ -32,6 +32,8 @@ static jfieldID _battery_level;
 
 void powermgmt_init_target(void)
 {
+    JNIEnv *env_ptr = getJavaEnvironment();
+
     jmethodID initBatteryMonitor = (*env_ptr)->GetMethodID(env_ptr,
                                                            RockboxService_class,
                                                            "initBatteryMonitor",
@@ -50,6 +52,8 @@ void powermgmt_init_target(void)
 
 int battery_level(void)
 {
+    JNIEnv *env_ptr = getJavaEnvironment();
+
     return (*env_ptr)->GetIntField(env_ptr, RockboxService_instance, _battery_level);
 }
 

firmware/target/hosted/android/system-android.c

@@ -27,7 +27,7 @@
 
 
 /* global fields for use with various JNI calls */
-JNIEnv *env_ptr;
+JavaVM *vm_ptr;
 jobject RockboxService_instance;
 jclass  RockboxService_class;
 
@@ -44,8 +44,11 @@ void system_reboot(void) { }
 
 void power_off(void)
 {
+    JNIEnv *env_ptr = getJavaEnvironment();
+
     lcd_deinit();
     pcm_deinit();
+
     (*env_ptr)->DeleteGlobalRef(env_ptr, RockboxService_class);
 }
 
@@ -68,8 +71,8 @@ Java_org_rockbox_RockboxService_main(JNIEnv *env, jobject this)
 
     volatile uintptr_t stack = 0;
     stackbegin = stackend = (uintptr_t*) &stack;
-    env_ptr = env;
 
+    (*env)->GetJavaVM(env, &vm_ptr);
     RockboxService_instance = (*env)->NewGlobalRef(env, this);
     RockboxService_class = (*env)->NewGlobalRef(env, class);
 

firmware/target/hosted/android/system-target.h

@@ -21,6 +21,8 @@
 #ifndef __SYSTEM_TARGET_H__
 #define __SYSTEM_TARGET_H__
 
+#include <jni.h>
+
 #define disable_irq()
 #define enable_irq()
 #define disable_irq_save() 0
@@ -30,6 +32,20 @@ void power_off(void);
 void wait_for_interrupt(void);
 void interrupt(void);
 
+/* A JNI environment is specific to its thread, so use the correct way to
+ * obtain it: share a pointer to the JavaVM structure and ask that the JNI
+ * environment attached to the current thread. */
+static inline JNIEnv* getJavaEnvironment(void)
+{
+    extern JavaVM *vm_ptr;
+    JNIEnv *env = NULL;
+
+    if (vm_ptr)
+        (*vm_ptr)->GetEnv(vm_ptr, (void**) &env, JNI_VERSION_1_2);
+
+    return env;
+}
+
 #endif /* __SYSTEM_TARGET_H__ */
 
 #define NEED_GENERIC_BYTESWAPS

firmware/target/hosted/android/telephony-android.c

@@ -22,14 +22,16 @@
 
 #include <jni.h>
 #include "kernel.h"
+#include "system.h"
 
-extern JNIEnv *env_ptr;
 extern jobject RockboxService_instance;
 
 
 void telephony_init_device(void)
 {
+    JNIEnv *env_ptr = getJavaEnvironment();
     JNIEnv e = *env_ptr;
+
     jclass class = e->FindClass(env_ptr, "org/rockbox/RockboxTelephony");
     jmethodID constructor = e->GetMethodID(env_ptr, class, "<init>", "(Landroid/content/Context;)V");