Finalize Android Java backend.

src/android/AndroidClient.cpp

@@ -7,7 +7,7 @@
 
 #include <dlfcn.h>
 
-std::string replace(const std::string &str, const std::string &from, const std::string &to)
+static std::string replace(const std::string &str, const std::string &from, const std::string &to)
 {
 	std::stringstream ss;
 	size_t oldpos = 0;
@@ -29,8 +29,9 @@ std::string replace(const std::string &str, const std::string &from, const std::
 	return ss.str();
 }
 
-jstring newStringUTF(JNIEnv *env, const std::string &str)
+static jstring newStringUTF(JNIEnv *env, const std::string &str)
 {
+	// We want std::string that contains null byte, hence length of 1.
 	static std::string null("", 1);
 
 	std::string newStr = replace(str, null, "\xC0\x80");
@@ -38,8 +39,9 @@ jstring newStringUTF(JNIEnv *env, const std::string &str)
 	return jstr;
 }
 
-std::string getStringUTF(JNIEnv *env, jstring str)
+static std::string getStringUTF(JNIEnv *env, jstring str)
 {
+	// We want std::string that contains null byte, hence length of 1.
 	static std::string null("", 1);
 
 	const char *c = env->GetStringUTFChars(str, nullptr);
@@ -55,19 +57,27 @@ AndroidClient::AndroidClient()
 {
 	// Look for SDL_AndroidGetJNIEnv
 	SDL_AndroidGetJNIEnv = (decltype(SDL_AndroidGetJNIEnv)) dlsym(RTLD_DEFAULT, "SDL_AndroidGetJNIEnv");
+	// Look for SDL_AndroidGetActivity
+	SDL_AndroidGetActivity = (decltype(SDL_AndroidGetActivity)) dlsym(RTLD_DEFAULT, "SDL_AndroidGetActivity");
 }
 
 bool AndroidClient::valid() const
 {
-	if (SDL_AndroidGetJNIEnv)
+	if (SDL_AndroidGetJNIEnv && SDL_AndroidGetActivity)
 	{
 		JNIEnv *env = SDL_AndroidGetJNIEnv();
 
 		if (env)
 		{
-			jclass httpsClass = env->FindClass("org/love2d/luahttps/LuaHTTPS");
+			jclass httpsClass = getHTTPSClass();
+			if (env->ExceptionCheck())
+			{
+				env->ExceptionClear();
+				return false;
+			}
+
 			env->DeleteLocalRef(httpsClass);
-			return httpsClass != nullptr;
+			return true;
 		}
 	}
 
@@ -77,7 +87,7 @@ bool AndroidClient::valid() const
 HTTPSClient::Reply AndroidClient::request(const HTTPSClient::Request &req)
 {
 	JNIEnv *env = SDL_AndroidGetJNIEnv();
-	jclass httpsClass = env->FindClass("org/love2d/luahttps/LuaHTTPS");
+	jclass httpsClass = getHTTPSClass();
 
 	if (httpsClass == nullptr)
 	{
@@ -172,4 +182,31 @@ HTTPSClient::Reply AndroidClient::request(const HTTPSClient::Request &req)
 	return response;
 }
 
+jclass AndroidClient::getHTTPSClass() const
+{
+	JNIEnv *env = SDL_AndroidGetJNIEnv();
+
+	jclass classLoaderClass = env->FindClass("java/lang/ClassLoader");
+	jmethodID loadClass = env->GetMethodID(classLoaderClass, "loadClass", "(Ljava/lang/String;)Ljava/lang/Class;");
+
+	jobject activity = SDL_AndroidGetActivity();
+
+	if (activity == nullptr)
+		return nullptr;
+
+	jclass gameActivity = env->GetObjectClass(activity);
+	jmethodID getLoader = env->GetMethodID(gameActivity, "getClassLoader", "()Ljava/lang/ClassLoader;");
+	jobject classLoader = env->CallObjectMethod(activity, getLoader);
+
+	jstring httpsClassName = env->NewStringUTF("org.love2d.luahttps.LuaHTTPS");
+	jclass httpsClass = (jclass) env->CallObjectMethod(classLoader, loadClass, httpsClassName);
+
+	env->DeleteLocalRef(gameActivity);
+	env->DeleteLocalRef(httpsClassName);
+	env->DeleteLocalRef(activity);
+	env->DeleteLocalRef(classLoaderClass);
+
+	return httpsClass;
+}
+
 #endif

src/android/AndroidClient.h

@@ -18,6 +18,9 @@ public:
 
 private:
 	JNIEnv *(*SDL_AndroidGetJNIEnv)();
+	jobject (*SDL_AndroidGetActivity)();
+
+	jclass getHTTPSClass() const;
 };
 
 #endif

src/android/java/org/love2d/luahttps/LuaHTTPS.java

@@ -12,6 +12,7 @@ import java.io.OutputStream;
 import java.net.HttpURLConnection;
 import java.net.MalformedURLException;
 import java.net.URL;
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -39,39 +40,51 @@ class LuaHTTPS {
         headers.clear();
     }
 
+    @Keep
     public void setUrl(String url) {
         urlString = url;
     }
 
+    @Keep
     public void setPostData(byte[] postData) {
         this.postData = postData;
     }
 
+    @Keep
     public void addHeader(String key, String value) {
         headers.put(key, value);
     }
 
+    @Keep
     public String[] getInterleavedHeaders() {
-        String[] result = new String[headers.size() * 2];
-        int i = 0;
+        ArrayList<String> resultInterleaved = new ArrayList<String>();
 
         for (Map.Entry<String, String> header: headers.entrySet()) {
-            result[i * 2] = header.getKey();
-            result[i * 2 + 1] = header.getValue();
-            i++;
+            String key = header.getKey();
+            String value = header.getValue();
+
+            if (key != null && value != null) {
+                resultInterleaved.add(key);
+                resultInterleaved.add(value);
+            }
         }
 
+        String[] result = new String[resultInterleaved.size()];
+        resultInterleaved.toArray(result);
         return result;
     }
 
+    @Keep
     public int getResponseCode() {
         return responseCode;
     }
 
+    @Keep
     public byte[] getResponse() {
         return response;
     }
 
+    @Keep
     public boolean request() {
         if (urlString == null) {
             return false;

src/android/ndk-build/common/config.h

@@ -0,0 +1,2 @@
+#define USE_ANDROID_BACKEND
+#define DLLEXPORT __attribute__((visibility ("default")))