android: Pass song information over the JNI bridge

android/app/src/main/java/org/musicpd/Bridge.java

@@ -5,6 +5,8 @@
 
 import android.content.Context;
 
+import org.musicpd.models.SongInfo;
+
 /**
  * Bridge to native code.
  */
@@ -18,4 +20,7 @@ public interface LogListener {
 	public static native void run(Context context, LogListener logListener);
 	public static native void shutdown();
 	public static native void pause();
+	public static native void playNext();
+	public static native void playPrevious();
+	public static native SongInfo currentSong();
 }

android/app/src/main/java/org/musicpd/models/SongInfo.java

@@ -0,0 +1,9 @@
+package org.musicpd.models;
+
+import java.util.HashMap;
+
+public class SongInfo {
+    String uri;
+    int durationMilliseconds;
+    HashMap<String, String> tags;
+}

android/include/meson.build

@@ -5,6 +5,7 @@ bridge_header = custom_target(
   output: 'org_musicpd_Bridge.h',
   input: [
     '../app/src/main/java/org/musicpd/Bridge.java',
+    '../app/src/main/java/org/musicpd/models/SongInfo.java',
   ],
   command: [
     javac,

meson.build

@@ -438,6 +438,7 @@ else
     'src/android/AudioManager.cxx',
     'src/android/Environment.cxx',
     'src/android/LogListener.cxx',
+    'src/android/Song.cxx',
   ]
 endif
 

src/Main.cxx

@@ -79,6 +79,7 @@
 #include "android/Environment.hxx"
 #include "android/Context.hxx"
 #include "android/LogListener.hxx"
+#include "android/Song.hxx"
 #include "config/File.hxx"
 #include "fs/FileSystem.hxx"
 #include "org_musicpd_Bridge.h"
@@ -614,6 +615,38 @@ Java_org_musicpd_Bridge_pause(JNIEnv *, jclass)
 			partition.pc.LockSetPause(true);
 }
 
+gcc_visibility_default
+JNIEXPORT void JNICALL
+Java_org_musicpd_Bridge_playNext(JNIEnv *, jclass)
+{
+
+}
+
+gcc_visibility_default
+JNIEXPORT void JNICALL
+Java_org_musicpd_Bridge_playPrevious(JNIEnv *, jclass)
+{
+
+}
+
+gcc_visibility_default
+JNIEXPORT jobject JNICALL
+Java_org_musicpd_Bridge_currentSong(JNIEnv *env, jclass)
+{
+    if (global_instance != nullptr) {
+        for (auto &partition : global_instance->partitions) {
+            int current_position = partition.playlist.GetCurrentPosition();
+            if (current_position < 0)
+                continue;
+
+            std::unique_ptr<DetachedSong> song = std::make_unique<DetachedSong>(partition.playlist.queue.Get(current_position));
+            return song_to_song_info(env, song);
+        }
+    }
+
+    return NULL;
+}
+
 #else
 
 static inline void

src/android/Song.cxx

@@ -0,0 +1,46 @@
+#include "Song.hxx"
+#include "java/Class.hxx"
+#include "tag/Names.hxx"
+
+jobject song_to_song_info(JNIEnv *env, std::unique_ptr<DetachedSong> &song) {
+    jobject tag_map = song_to_tag_hashmap(env, song);
+
+    Java::Class cls(env, "org/musicpd/models/SongInfo");
+    jmethodID init = env->GetMethodID(cls, "<init>", "()V");
+    jobject song_info = env->NewObject(cls, init);
+
+    jstring uri = env->NewStringUTF(song->GetURI());
+    jfieldID id_uri = env->GetFieldID(cls, "uri", "Ljava/lang/String;");
+    env->SetObjectField(song_info, id_uri, uri);
+    env->DeleteLocalRef(uri);
+
+    const auto duration = song->GetDuration();
+    jfieldID id_duration = env->GetFieldID(cls, "durationMilliseconds", "I");
+    env->SetIntField(song_info, id_duration, duration.ToMS());
+
+    jfieldID id_tags = env->GetFieldID(cls, "tags", "Ljava/util/HashMap;");
+    env->SetObjectField(song_info, id_tags, tag_map);
+    env->DeleteLocalRef(tag_map);
+
+    return song_info;
+}
+
+jobject song_to_tag_hashmap(JNIEnv *env, std::unique_ptr<DetachedSong> &song) {
+    Java::Class cls(env, "java/util/HashMap");
+    jmethodID init = env->GetMethodID(cls, "<init>", "()V");
+    jobject hash_map = env->NewObject(cls, init);
+    jmethodID put = env->GetMethodID(cls, "put", "(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;");
+
+    const Tag &tag = song->GetTag();
+    for (const auto &i : tag) {
+        jstring key = env->NewStringUTF(tag_item_names[i.type]);
+        jstring value = env->NewStringUTF(i.value);
+
+        env->CallObjectMethod(hash_map, put, key, value);
+
+        env->DeleteLocalRef(key);
+        env->DeleteLocalRef(value);
+    }
+
+    return hash_map;
+}

src/android/Song.hxx

@@ -0,0 +1,7 @@
+#include "song/DetachedSong.hxx"
+
+#include "java/Object.hxx"
+
+jobject song_to_song_info(JNIEnv *env, std::unique_ptr<DetachedSong> &song);
+
+jobject song_to_tag_hashmap(JNIEnv *env, std::unique_ptr<DetachedSong> &song);