android: Add savestates UI

A simple menu with savestates info.

src/android/app/src/main/java/org/citra/citra_emu/NativeLibrary.java

@@ -16,6 +16,7 @@ import android.widget.EditText;
 import android.widget.FrameLayout;
 import android.widget.TextView;
 
+import androidx.annotation.Nullable;
 import androidx.appcompat.app.AlertDialog;
 import androidx.core.content.ContextCompat;
 
@@ -25,6 +26,7 @@ import org.citra.citra_emu.utils.Log;
 import org.citra.citra_emu.utils.PermissionsHandler;
 
 import java.lang.ref.WeakReference;
+import java.util.Date;
 
 import static android.Manifest.permission.CAMERA;
 import static android.Manifest.permission.RECORD_AUDIO;
@@ -487,6 +489,19 @@ public final class NativeLibrary {
 
     public static native void InstallCIAS(String[] path);
 
+    public static final int SAVESTATE_SLOT_COUNT = 10;
+
+    public static final class SavestateInfo {
+        public int slot;
+        public Date time;
+    }
+
+    @Nullable
+    public static native SavestateInfo[] GetSavestateInfo();
+
+    public static native void SaveState(int slot);
+    public static native void LoadState(int slot);
+
     /**
      * Button type for use in onTouchEvent
      */

src/android/app/src/main/java/org/citra/citra_emu/activities/EmulationActivity.java

@@ -14,6 +14,7 @@ import android.view.LayoutInflater;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.MotionEvent;
+import android.view.SubMenu;
 import android.view.View;
 import android.widget.SeekBar;
 import android.widget.TextView;
@@ -303,6 +304,45 @@ public final class EmulationActivity extends AppCompatActivity {
         return true;
     }
 
+    @Override
+    public boolean onPrepareOptionsMenu(Menu menu) {
+        super.onPrepareOptionsMenu(menu);
+
+        final NativeLibrary.SavestateInfo[] savestates = NativeLibrary.GetSavestateInfo();
+        if (savestates == null) {
+            menu.findItem(R.id.menu_emulation_save_state).setVisible(false);
+            menu.findItem(R.id.menu_emulation_load_state).setVisible(false);
+            return true;
+        }
+        menu.findItem(R.id.menu_emulation_save_state).setVisible(true);
+        menu.findItem(R.id.menu_emulation_load_state).setVisible(true);
+
+        final SubMenu saveStateMenu = menu.findItem(R.id.menu_emulation_save_state).getSubMenu();
+        final SubMenu loadStateMenu = menu.findItem(R.id.menu_emulation_load_state).getSubMenu();
+        saveStateMenu.clear();
+        loadStateMenu.clear();
+
+        // Update savestates information
+        for (int i = 0; i < NativeLibrary.SAVESTATE_SLOT_COUNT; ++i) {
+            final int slot = i + 1;
+            final String text = getString(R.string.emulation_empty_state_slot, slot);
+            saveStateMenu.add(text).setEnabled(true).setOnMenuItemClickListener((item) -> {
+                NativeLibrary.SaveState(slot);
+                return true;
+            });
+            loadStateMenu.add(text).setEnabled(false).setOnMenuItemClickListener((item) -> {
+                NativeLibrary.LoadState(slot);
+                return true;
+            });
+        }
+        for (final NativeLibrary.SavestateInfo info : savestates) {
+            final String text = getString(R.string.emulation_occupied_state_slot, info.slot, info.time);
+            saveStateMenu.getItem(info.slot - 1).setTitle(text);
+            loadStateMenu.getItem(info.slot - 1).setTitle(text).setEnabled(true);
+        }
+        return true;
+    }
+
     @SuppressWarnings("WrongConstant")
     @Override
     public boolean onOptionsItemSelected(MenuItem item) {

src/android/app/src/main/jni/id_cache.cpp

@@ -19,6 +19,7 @@ static constexpr jint JNI_VERSION = JNI_VERSION_1_6;
 static JavaVM* s_java_vm;
 
 static jclass s_native_library_class;
+static jclass s_savestate_info_class;
 static jmethodID s_display_alert_msg;
 static jmethodID s_display_alert_prompt;
 static jmethodID s_alert_prompt_button;
@@ -53,6 +54,10 @@ jclass GetNativeLibraryClass() {
     return s_native_library_class;
 }
 
+jclass GetSavestateInfoClass() {
+    return s_savestate_info_class;
+}
+
 jmethodID GetDisplayAlertMsg() {
     return s_display_alert_msg;
 }
@@ -111,6 +116,8 @@ jint JNI_OnLoad(JavaVM* vm, void* reserved) {
     // Initialize Java methods
     const jclass native_library_class = env->FindClass("org/citra/citra_emu/NativeLibrary");
     s_native_library_class = reinterpret_cast<jclass>(env->NewGlobalRef(native_library_class));
+    s_savestate_info_class = reinterpret_cast<jclass>(
+        env->NewGlobalRef(env->FindClass("org/citra/citra_emu/NativeLibrary$SavestateInfo")));
     s_display_alert_msg = env->GetStaticMethodID(s_native_library_class, "displayAlertMsg",
                                                  "(Ljava/lang/String;Ljava/lang/String;Z)Z");
     s_display_alert_prompt =
@@ -142,6 +149,7 @@ void JNI_OnUnload(JavaVM* vm, void* reserved) {
     }
 
     env->DeleteGlobalRef(s_native_library_class);
+    env->DeleteGlobalRef(s_savestate_info_class);
     MiiSelector::CleanupJNI(env);
     SoftwareKeyboard::CleanupJNI(env);
     Camera::StillImage::CleanupJNI(env);

src/android/app/src/main/jni/id_cache.h

@@ -12,6 +12,7 @@ namespace IDCache {
 
 JNIEnv* GetEnvForThread();
 jclass GetNativeLibraryClass();
+jclass GetSavestateInfoClass();
 jmethodID GetDisplayAlertMsg();
 jmethodID GetDisplayAlertPrompt();
 jmethodID GetAlertPromptButton();

src/android/app/src/main/jni/native.cpp

@@ -23,6 +23,7 @@
 #include "core/frontend/scope_acquire_context.h"
 #include "core/hle/service/am/am.h"
 #include "core/hle/service/nfc/nfc.h"
+#include "core/savestate.h"
 #include "core/settings.h"
 #include "jni/applets/mii_selector.h"
 #include "jni/applets/swkbd.h"
@@ -620,4 +621,47 @@ void Java_org_citra_citra_1emu_NativeLibrary_InstallCIAS(JNIEnv* env, [[maybe_un
         thread.join();
 }
 
+jobjectArray Java_org_citra_citra_1emu_NativeLibrary_GetSavestateInfo(
+    JNIEnv* env, [[maybe_unused]] jclass clazz) {
+    const jclass date_class = env->FindClass("java/util/Date");
+    const auto date_constructor = env->GetMethodID(date_class, "<init>", "(J)V");
+
+    const jclass savestate_info_class = IDCache::GetSavestateInfoClass();
+    const auto slot_field = env->GetFieldID(savestate_info_class, "slot", "I");
+    const auto date_field = env->GetFieldID(savestate_info_class, "time", "Ljava/util/Date;");
+
+    const Core::System& system{Core::System::GetInstance()};
+    if (!system.IsPoweredOn()) {
+        return nullptr;
+    }
+
+    u64 title_id;
+    if (system.GetAppLoader().ReadProgramId(title_id) != Loader::ResultStatus::Success) {
+        return nullptr;
+    }
+
+    const auto savestates = Core::ListSaveStates(title_id);
+    const jobjectArray array =
+        env->NewObjectArray(static_cast<jsize>(savestates.size()), savestate_info_class, nullptr);
+    for (std::size_t i = 0; i < savestates.size(); ++i) {
+        const jobject object = env->AllocObject(savestate_info_class);
+        env->SetIntField(object, slot_field, static_cast<jint>(savestates[i].slot));
+        env->SetObjectField(object, date_field,
+                            env->NewObject(date_class, date_constructor,
+                                           static_cast<jlong>(savestates[i].time * 1000)));
+
+        env->SetObjectArrayElement(array, i, object);
+    }
+    LOG_CRITICAL(Frontend, "Called");
+    return array;
+}
+
+void Java_org_citra_citra_1emu_NativeLibrary_SaveState(JNIEnv* env, jclass clazz, jint slot) {
+    Core::System::GetInstance().SendSignal(Core::System::Signal::Save, slot);
+}
+
+void Java_org_citra_citra_1emu_NativeLibrary_LoadState(JNIEnv* env, jclass clazz, jint slot) {
+    Core::System::GetInstance().SendSignal(Core::System::Signal::Load, slot);
+}
+
 } // extern "C"

src/android/app/src/main/jni/native.h

@@ -146,6 +146,15 @@ JNIEXPORT void JNICALL Java_org_citra_citra_1emu_NativeLibrary_InstallCIAS(JNIEn
                                                                            jclass clazz,
                                                                            jobjectArray path);
 
+JNIEXPORT jobjectArray JNICALL
+Java_org_citra_citra_1emu_NativeLibrary_GetSavestateInfo(JNIEnv* env, jclass clazz);
+
+JNIEXPORT void JNICALL Java_org_citra_citra_1emu_NativeLibrary_SaveState(JNIEnv* env, jclass clazz,
+                                                                         jint slot);
+
+JNIEXPORT void JNICALL Java_org_citra_citra_1emu_NativeLibrary_LoadState(JNIEnv* env, jclass clazz,
+                                                                         jint slot);
+
 #ifdef __cplusplus
 }
 #endif

src/android/app/src/main/res/menu/menu_emulation.xml

@@ -3,6 +3,18 @@
     xmlns:app="http://schemas.android.com/apk/res-auto"
     tools:context="org.citra.citra_emu.activities.EmulationActivity">
 
+    <item
+        android:id="@+id/menu_emulation_save_state"
+        android:title="@string/emulation_save_state">
+        <menu/>
+    </item>
+
+    <item
+        android:id="@+id/menu_emulation_load_state"
+        android:title="@string/emulation_load_state">
+        <menu/>
+    </item>
+
     <item
         android:id="@+id/menu_emulation_configure_controls"
         android:title="@string/emulation_configure_controls">

src/android/app/src/main/res/values/strings.xml

@@ -143,6 +143,10 @@
     <string name="loader_error_invalid_format">Invalid ROM format</string>
 
     <!-- Emulation Menu -->
+    <string name="emulation_save_state">Save State</string>
+    <string name="emulation_load_state">Load State</string>
+    <string name="emulation_empty_state_slot">Slot %1$d</string>
+    <string name="emulation_occupied_state_slot">Slot %1$d - %2$tF %2$tR</string>
     <string name="emulation_show_fps">Show FPS</string>
     <string name="emulation_configure_controls">Configure Controls</string>
     <string name="emulation_edit_layout">Edit Layout</string>