Fix JNI Race Condition, Fix Release Builds and Fix Searching

This commit fixes JNI race conditions by usage of a mutex, fixes a bug in release builds due to ProGuard member obfuscation and fix searching by fixing the HeaderAdapter filter.

app/src/main/cpp/skyline/jvm.h

@@ -0,0 +1,64 @@
+#pragma once
+
+#include <common.h>
+#include <jni.h>
+
+namespace skyline {
+    /**
+     * @brief The JvmManager class is used to simplify transactions with the Java component
+     */
+    class JvmManager {
+      public:
+        JNIEnv *env; //!< A pointer to the JNI environment
+        jobject instance; //!< A reference to the activity
+        jclass instanceClass; //!< The class of the activity
+
+        /**
+         * @param env A pointer to the JNI environment
+         * @param instance A reference to the activity
+         */
+        JvmManager(JNIEnv *env, jobject instance);
+
+        /**
+         * @brief Retrieves a specific field of the given type from the activity
+         * @tparam objectType The type of the object in the field
+         * @param key The name of the field in the activity class
+         * @return The contents of the field as objectType
+         */
+        template<typename objectType>
+        inline objectType GetField(const char *key) {
+            if constexpr(std::is_same<objectType, jboolean>())
+                return env->GetBooleanField(instance, env->GetFieldID(instanceClass, key, "Z"));
+            else if constexpr(std::is_same<objectType, jbyte>())
+                return env->GetByteField(instance, env->GetFieldID(instanceClass, key, "B"));
+            else if constexpr(std::is_same<objectType, jchar>())
+                return env->GetCharField(instance, env->GetFieldID(instanceClass, key, "C"));
+            else if constexpr(std::is_same<objectType, jshort>())
+                return env->GetShortField(instance, env->GetFieldID(instanceClass, key, "S"));
+            else if constexpr(std::is_same<objectType, jint>())
+                return env->GetIntField(instance, env->GetFieldID(instanceClass, key, "I"));
+            else if constexpr(std::is_same<objectType, jlong>())
+                return env->GetLongField(instance, env->GetFieldID(instanceClass, key, "J"));
+            else if constexpr(std::is_same<objectType, jfloat>())
+                return env->GetFloatField(instance, env->GetFieldID(instanceClass, key, "F"));
+            else if constexpr(std::is_same<objectType, jdouble>())
+                return env->GetDoubleField(instance, env->GetFieldID(instanceClass, key, "D"));
+        }
+
+        /**
+         * @brief Retrieves a specific field from the activity as a jobject
+         * @param key The name of the field in the activity class
+         * @param signature The signature of the field
+         * @return A jobject of the contents of the field
+         */
+        jobject GetField(const char *key, const char *signature);
+
+        /**
+         * @brief Checks if a specific field from the activity is null or not
+         * @param key The name of the field in the activity class
+         * @param signature The signature of the field
+         * @return If the field is null or not
+         */
+        bool CheckNull(const char *key, const char *signature);
+    };
+}