[android] set datadir path from system environment

android/jni/DaemonAndroid.cpp

@@ -65,6 +65,8 @@ namespace android
 		}
 	}
 */
+	std::string dataDir = "";
+
 	DaemonAndroidImpl::DaemonAndroidImpl ()
 		//:
 		/*mutex(nullptr), */
@@ -85,7 +87,7 @@ namespace android
 		//m_IsRunning=false;
 
 		// make sure assets are ready before proceed
-		i2p::fs::DetectDataDir("", false);
+		i2p::fs::DetectDataDir(dataDir, false);
 		int numAttempts = 0;
 		do
 		{
@@ -203,5 +205,10 @@ namespace android
 	{
 		daemon.stop();
 	}
+
+	void SetDataDir(std::string jdataDir)
+	{
+		dataDir = jdataDir;
+	}
 }
 }

android/jni/DaemonAndroid.h

@@ -42,6 +42,8 @@ namespace android
 	// stops the daemon
 	void stop();
 
+	// set datadir received from jni
+	void SetDataDir(std::string jdataDir);
 	/*
 	class Worker : public QObject
 	{

android/jni/i2pd_android.cpp

@@ -5,7 +5,7 @@
 #include "Transports.h"
 
 JNIEXPORT jstring JNICALL Java_org_purplei2p_i2pd_I2PD_1JNI_getABICompiledWith
-	(JNIEnv * env, jclass clazz) {
+	(JNIEnv *env, jclass clazz) {
 #if defined(__arm__)
 	#if defined(__ARM_ARCH_7A__)
 		#if defined(__ARM_NEON__)
@@ -42,27 +42,53 @@ JNIEXPORT jstring JNICALL Java_org_purplei2p_i2pd_I2PD_1JNI_getABICompiledWith
 }
 
 JNIEXPORT jstring JNICALL Java_org_purplei2p_i2pd_I2PD_1JNI_startDaemon
-	(JNIEnv * env, jclass clazz) {
+	(JNIEnv *env, jclass clazz) {
 	return env->NewStringUTF(i2p::android::start().c_str());
 }
 
 JNIEXPORT void JNICALL Java_org_purplei2p_i2pd_I2PD_1JNI_stopDaemon
-	(JNIEnv * env, jclass clazz) {
+	(JNIEnv *env, jclass clazz) {
 	i2p::android::stop();
 }
 
 JNIEXPORT void JNICALL Java_org_purplei2p_i2pd_I2PD_1JNI_stopAcceptingTunnels
-	(JNIEnv * env, jclass clazz) {
+	(JNIEnv *env, jclass clazz) {
 	i2p::context.SetAcceptsTunnels (false);
 }
 
 JNIEXPORT void JNICALL Java_org_purplei2p_i2pd_I2PD_1JNI_startAcceptingTunnels
-	(JNIEnv * env, jclass clazz) {
+	(JNIEnv *env, jclass clazz) {
 	i2p::context.SetAcceptsTunnels (true);
 }
 
 JNIEXPORT void JNICALL Java_org_purplei2p_i2pd_I2PD_1JNI_onNetworkStateChanged
-	(JNIEnv * env, jclass clazz, jboolean isConnected) {
+	(JNIEnv *env, jclass clazz, jboolean isConnected) {
 	bool isConnectedBool = (bool) isConnected;
 	i2p::transport::transports.SetOnline (isConnectedBool);
 }
+
+JNIEXPORT void JNICALL Java_org_purplei2p_i2pd_I2PD_1JNI_setDataDir
+	(JNIEnv *env, jclass clazz, jstring jdataDir) {
+
+	/*
+	// Method 1: convert UTF-16 jstring to std::string (https://stackoverflow.com/a/41820336)
+	const jclass stringClass = env->GetObjectClass(jdataDir);
+	const jmethodID getBytes = env->GetMethodID(stringClass, "getBytes", "(Ljava/lang/String;)[B");
+	const jbyteArray stringJbytes = (jbyteArray) env->CallObjectMethod(jdataDir, getBytes, env->NewStringUTF("UTF-8"));
+
+	size_t length = (size_t) env->GetArrayLength(stringJbytes);
+	jbyte* pBytes = env->GetByteArrayElements(stringJbytes, NULL);
+
+	std::string dataDir = std::string((char *)pBytes, length);
+	env->ReleaseByteArrayElements(stringJbytes, pBytes, JNI_ABORT);
+
+	env->DeleteLocalRef(stringJbytes);
+	env->DeleteLocalRef(stringClass); */
+
+	// Method 2: get string chars and make char array.
+	auto dataDir = env->GetStringUTFChars(jdataDir, NULL);
+	env->ReleaseStringUTFChars(jdataDir, dataDir);
+
+	// Set DataDir
+	i2p::android::SetDataDir(dataDir);
+}

android/jni/org_purplei2p_i2pd_I2PD_JNI.h

@@ -30,6 +30,9 @@ JNIEXPORT void JNICALL Java_org_purplei2p_i2pd_I2PD_1JNI_startAcceptingTunnels
 JNIEXPORT void JNICALL Java_org_purplei2p_i2pd_I2PD_1JNI_onNetworkStateChanged
 	(JNIEnv * env, jclass clazz, jboolean isConnected);
 
+JNIEXPORT void JNICALL Java_org_purplei2p_i2pd_I2PD_1JNI_setDataDir
+	(JNIEnv *env, jclass clazz, jstring jdataDir);
+
 #ifdef __cplusplus
 }
 #endif

android/src/org/purplei2p/i2pd/DaemonSingleton.java

@@ -2,7 +2,9 @@ package org.purplei2p.i2pd;
 
 import java.util.HashSet;
 import java.util.Set;
+import android.os.Environment;
 import android.util.Log;
+
 import org.purplei2p.i2pd.R;
 
 public class DaemonSingleton {
@@ -80,6 +82,7 @@ public class DaemonSingleton {
 				}
 				try {
 					synchronized (DaemonSingleton.this) {
+						I2PD_JNI.setDataDir(Environment.getExternalStorageDirectory().getAbsolutePath() + "/i2pd");
 						daemonStartResult = I2PD_JNI.startDaemon();
 						if("ok".equals(daemonStartResult)){
 							setState(State.startedOkay);

android/src/org/purplei2p/i2pd/I2PD_JNI.java

@@ -18,6 +18,8 @@ public class I2PD_JNI {
 
 	public static native void onNetworkStateChanged(boolean isConnected);
 
+	public static native void setDataDir(String jdataDir);
+
 	public static void loadLibraries() {
 		//System.loadLibrary("c++_shared");
 		System.loadLibrary("i2pd");