From 6be8476f90986687dc7c16a018196ce0db490fd9 Mon Sep 17 00:00:00 2001
From: Stanislav Dmitrenko <7953703+avently@users.noreply.github.com>
Date: Wed, 26 Jul 2023 14:38:49 +0300
Subject: [PATCH] desktop: decoding utf8 (#2774)

---
 .../src/commonMain/cpp/desktop/simplex-api.c  | 37 +++++++++++++++----
 1 file changed, 30 insertions(+), 7 deletions(-)

diff --git a/apps/multiplatform/common/src/commonMain/cpp/desktop/simplex-api.c b/apps/multiplatform/common/src/commonMain/cpp/desktop/simplex-api.c
index 2f7299393c..2c3e123fd5 100644
--- a/apps/multiplatform/common/src/commonMain/cpp/desktop/simplex-api.c
+++ b/apps/multiplatform/common/src/commonMain/cpp/desktop/simplex-api.c
@@ -1,4 +1,5 @@
 #include <jni.h>
+#include <string.h>
 
 // from the RTS
 void hs_init(int * argc, char **argv[]);
@@ -30,13 +31,35 @@ extern char *chat_parse_markdown(const char *str);
 extern char *chat_parse_server(const char *str);
 extern char *chat_password_hash(const char *pwd, const char *salt);
 
+
+// As a reference: https://stackoverflow.com/a/60002045
+jstring correct_string_utf8(JNIEnv *env, char *string) {
+    jobject bb = (*env)->NewDirectByteBuffer(env, (void *)string, strlen(string));
+    jclass cls_charset = (*env)->FindClass(env, "java/nio/charset/Charset");
+    jmethodID mid_charset_forName = (*env)->GetStaticMethodID(env, cls_charset, "forName", "(Ljava/lang/String;)Ljava/nio/charset/Charset;");
+    jobject charset = (*env)->CallStaticObjectMethod(env, cls_charset, mid_charset_forName, (*env)->NewStringUTF(env, "UTF-8"));
+
+    jmethodID mid_decode = (*env)->GetMethodID(env, cls_charset, "decode", "(Ljava/nio/ByteBuffer;)Ljava/nio/CharBuffer;");
+    jobject cb = (*env)->CallObjectMethod(env, charset, mid_decode, bb);
+
+    jclass cls_char_buffer = (*env)->FindClass(env, "java/nio/CharBuffer");
+    jmethodID mid_to_string = (*env)->GetMethodID(env, cls_char_buffer, "toString", "()Ljava/lang/String;");
+    jstring res = (*env)->CallObjectMethod(env, cb, mid_to_string);
+
+    (*env)->DeleteLocalRef(env, bb);
+    (*env)->DeleteLocalRef(env, charset);
+    (*env)->DeleteLocalRef(env, cb);
+    return res;
+}
+
+
 JNIEXPORT jobjectArray JNICALL
 Java_chat_simplex_common_platform_CoreKt_chatMigrateInit(JNIEnv *env, jclass clazz, jstring dbPath, jstring dbKey, jstring confirm) {
     const char *_dbPath = (*env)->GetStringUTFChars(env, dbPath, JNI_FALSE);
     const char *_dbKey = (*env)->GetStringUTFChars(env, dbKey, JNI_FALSE);
     const char *_confirm = (*env)->GetStringUTFChars(env, confirm, JNI_FALSE);
     jlong _ctrl = (jlong) 0;
-    jstring res = (*env)->NewStringUTF(env, chat_migrate_init(_dbPath, _dbKey, _confirm, &_ctrl));
+    jstring res = correct_string_utf8(env, chat_migrate_init(_dbPath, _dbKey, _confirm, &_ctrl));
     (*env)->ReleaseStringUTFChars(env, dbPath, _dbPath);
     (*env)->ReleaseStringUTFChars(env, dbKey, _dbKey);
     (*env)->ReleaseStringUTFChars(env, dbKey, _confirm);
@@ -56,25 +79,25 @@ Java_chat_simplex_common_platform_CoreKt_chatMigrateInit(JNIEnv *env, jclass cla
 JNIEXPORT jstring JNICALL
 Java_chat_simplex_common_platform_CoreKt_chatSendCmd(JNIEnv *env, jclass clazz, jlong controller, jstring msg) {
     const char *_msg = (*env)->GetStringUTFChars(env, msg, JNI_FALSE);
-    jstring res = (*env)->NewStringUTF(env, chat_send_cmd((void*)controller, _msg));
+    jstring res = correct_string_utf8(env, chat_send_cmd((void*)controller, _msg));
     (*env)->ReleaseStringUTFChars(env, msg, _msg);
     return res;
 }
 
 JNIEXPORT jstring JNICALL
 Java_chat_simplex_common_platform_CoreKt_chatRecvMsg(JNIEnv *env, jclass clazz, jlong controller) {
-    return (*env)->NewStringUTF(env, chat_recv_msg((void*)controller));
+    return correct_string_utf8(env, chat_recv_msg((void*)controller));
 }
 
 JNIEXPORT jstring JNICALL
 Java_chat_simplex_common_platform_CoreKt_chatRecvMsgWait(JNIEnv *env, jclass clazz, jlong controller, jint wait) {
-    return (*env)->NewStringUTF(env, chat_recv_msg_wait((void*)controller, wait));
+    return correct_string_utf8(env, chat_recv_msg_wait((void*)controller, wait));
 }
 
 JNIEXPORT jstring JNICALL
 Java_chat_simplex_common_platform_CoreKt_chatParseMarkdown(JNIEnv *env, jclass clazz, jstring str) {
     const char *_str = (*env)->GetStringUTFChars(env, str, JNI_FALSE);
-    jstring res = (*env)->NewStringUTF(env, chat_parse_markdown(_str));
+    jstring res = correct_string_utf8(env, chat_parse_markdown(_str));
     (*env)->ReleaseStringUTFChars(env, str, _str);
     return res;
 }
@@ -82,7 +105,7 @@ Java_chat_simplex_common_platform_CoreKt_chatParseMarkdown(JNIEnv *env, jclass c
 JNIEXPORT jstring JNICALL
 Java_chat_simplex_common_platform_CoreKt_chatParseServer(JNIEnv *env, jclass clazz, jstring str) {
     const char *_str = (*env)->GetStringUTFChars(env, str, JNI_FALSE);
-    jstring res = (*env)->NewStringUTF(env, chat_parse_server(_str));
+    jstring res = correct_string_utf8(env, chat_parse_server(_str));
     (*env)->ReleaseStringUTFChars(env, str, _str);
     return res;
 }
@@ -91,7 +114,7 @@ JNIEXPORT jstring JNICALL
 Java_chat_simplex_common_platform_CoreKt_chatPasswordHash(JNIEnv *env, jclass clazz, jstring pwd, jstring salt) {
     const char *_pwd = (*env)->GetStringUTFChars(env, pwd, JNI_FALSE);
     const char *_salt = (*env)->GetStringUTFChars(env, salt, JNI_FALSE);
-    jstring res = (*env)->NewStringUTF(env, chat_password_hash(_pwd, _salt));
+    jstring res = correct_string_utf8(env, chat_password_hash(_pwd, _salt));
     (*env)->ReleaseStringUTFChars(env, pwd, _pwd);
     (*env)->ReleaseStringUTFChars(env, salt, _salt);
     return res;