android: add LogListener

A Java object to send logs on the android side.

Makefile.am

@@ -276,7 +276,8 @@ libjava_a_SOURCES = \
 noinst_LIBRARIES += libandroid.a
 libandroid_a_SOURCES = \
 	src/android/Context.cxx src/android/Context.hxx \
-	src/android/Environment.cxx src/android/Environment.hxx
+	src/android/Environment.cxx src/android/Environment.hxx \
+	src/android/LogListener.cxx src/android/LogListener.hxx
 libandroid_a_CPPFLAGS = $(AM_CPPFLAGS) -Iandroid/build/include
 
 noinst_LIBRARIES += libmain.a

android/src/Bridge.java

@@ -25,6 +25,12 @@ import android.content.Context;
  * Bridge to native code.
  */
 public class Bridge {
-	public static native void run(Context context);
+
+	/* used by jni */
+	public interface LogListener {
+		public void onLog(int priority, String msg);
+	}
+
+	public static native void run(Context context, LogListener logListener);
 	public static native void shutdown();
 }

android/src/Main.java

@@ -69,7 +69,7 @@ public class Main extends Activity implements Runnable {
 	}
 
 	@Override public void run() {
-		Bridge.run(this);
+		Bridge.run(this, null);
 		quitHandler.sendMessage(quitHandler.obtainMessage());
 	}
 }

src/LogBackend.cxx

@@ -34,6 +34,8 @@
 
 #ifdef ANDROID
 #include <android/log.h>
+#include "android/LogListener.hxx"
+#include "Main.hxx"
 
 static int
 ToAndroidLogLevel(LogLevel log_level)
@@ -177,6 +179,9 @@ Log(const Domain &domain, LogLevel level, const char *msg)
 #ifdef ANDROID
 	__android_log_print(ToAndroidLogLevel(level), "MPD",
 			    "%s: %s", domain.GetName(), msg);
+	if (logListener != nullptr)
+		logListener->OnLog(Java::GetEnv(), ToAndroidLogLevel(level),
+				   "%s: %s", domain.GetName(), msg);
 #else
 
 	if (level < log_threshold)

src/Main.cxx

@@ -92,6 +92,7 @@
 #include "java/File.hxx"
 #include "android/Environment.hxx"
 #include "android/Context.hxx"
+#include "android/LogListener.hxx"
 #include "fs/StandardDirectory.hxx"
 #include "fs/FileSystem.hxx"
 #include "org_musicpd_Bridge.h"
@@ -128,6 +129,7 @@ static constexpr unsigned DEFAULT_BUFFER_BEFORE_PLAY = 10;
 
 #ifdef ANDROID
 Context *context;
+LogListener *logListener;
 #endif
 
 Instance *instance;
@@ -676,16 +678,19 @@ try {
 
 gcc_visibility_default
 JNIEXPORT void JNICALL
-Java_org_musicpd_Bridge_run(JNIEnv *env, jclass, jobject _context)
+Java_org_musicpd_Bridge_run(JNIEnv *env, jclass, jobject _context, jobject _logListener)
 {
 	Java::Init(env);
 	Java::File::Initialise(env);
 	Environment::Initialise(env);
 
 	context = new Context(env, _context);
+	if (_logListener != nullptr)
+		logListener = new LogListener(env, _logListener);
 
 	mpd_main(0, nullptr);
 
+	delete logListener;
 	delete context;
 	Environment::Deinitialise(env);
 }

src/Main.hxx

@@ -25,7 +25,10 @@ class Context;
 struct Instance;
 
 #ifdef ANDROID
+#include "android/LogListener.hxx"
+
 extern Context *context;
+extern LogListener *logListener;
 #endif
 
 extern Instance *instance;

src/android/LogListener.cxx

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2003-2018 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "LogListener.hxx"
+#include "java/Class.hxx"
+#include "java/String.hxx"
+#include "util/AllocatedString.hxx"
+#include "util/FormatString.hxx"
+
+void
+LogListener::OnLog(JNIEnv *env, int priority, const char *fmt, ...) const
+{
+	assert(env != nullptr);
+
+	Java::Class cls(env, env->GetObjectClass(Get()));
+
+	jmethodID method = env->GetMethodID(cls, "onLog",
+					    "(ILjava/lang/String;)V");
+
+	assert(method);
+
+	va_list args;
+	va_start(args, fmt);
+	const auto log = FormatStringV(fmt, args);
+	va_end(args);
+
+	env->CallVoidMethod(Get(), method, priority,
+			    Java::String(env, log.c_str()).Get());
+}

src/android/LogListener.hxx

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2003-2018 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_ANDROID_LOG_LISTENER_HXX
+#define MPD_ANDROID_LOG_LISTENER_HXX
+
+#include "java/Object.hxx"
+
+class LogListener : public Java::Object {
+public:
+	LogListener(JNIEnv *env, jobject obj):Java::Object(env, obj) {}
+
+	void OnLog(JNIEnv *env, int priority, const char *fmt, ...) const;
+};
+
+#endif