Add libs:sftp

sftp implementation using libssh2 and openssl

2 files changed, 140 insertions, 1 deletions

diff --git a/libs/samba/src/main/cpp/jni.cpp b/libs/samba/src/main/cpp/jni.cpp
index 5a69dc5..b7bbd1a 100644
--- a/libs/samba/src/main/cpp/jni.cpp
+++ b/libs/samba/src/main/cpp/jni.cpp
@@ -1,5 +1,8 @@
 #include "jni.hpp"
 
+#include <algorithm>
+#include <optional>
+
 #ifdef ANDROID
 #include <android/log.h>
 #else
@@ -31,6 +34,103 @@ const char *_jni_error(jint err) {
   }
 }
 
+const char* u8_read(const char* str, uint32_t& out) {
+  // Assume valid UTF-8 for speed and so it can be used to read modified utf-8 as well
+  switch (*str >> 4) {
+    case 0xf: // 4 byte
+      out = (static_cast<uint32_t>(str[0] & 0x7) << 18) |
+            (static_cast<uint32_t>(str[1] & 0x3f) << 12) |
+            (static_cast<uint32_t>(str[2] & 0x3f) << 6) |
+            static_cast<uint8_t>(str[3] & 0x3f);
+      return str + 4;
+    case 0xe: // 3 byte
+      out = (static_cast<uint32_t>(str[0] & 0xf) << 12) |
+            (static_cast<uint32_t>(str[1] & 0x3f) << 6) |
+            static_cast<uint8_t>(str[2] & 0x3f);
+      return str + 3;
+    case 0xd:
+    case 0xc: // 2 byte
+      out = (static_cast<uint32_t>(str[0] & 0x1f) << 6) |
+          static_cast<uint8_t>(str[1] & 0x3f);
+      return str + 2;
+    default: // 1 byte
+      out = static_cast<uint8_t>(str[0]);
+      return str + 1;
+  }
+}
+
+void u8_write(std::string& ret, uint32_t c) {
+  if (c < 0x80) {
+    ret.push_back(static_cast<char>(c));
+  } else if (c < 0x800) {
+    ret.push_back(static_cast<char>(0xc0 | (c >> 6)));
+    ret.push_back(static_cast<char>(0x80 | (c & 0x3f)));
+  } else if (c < 0x10000) {
+    ret.push_back(static_cast<char>(0xe0 | (c >> 12)));
+    ret.push_back(static_cast<char>(0x80 | ((c >> 6) & 0x3f)));
+    ret.push_back(static_cast<char>(0x80 | (c & 0x3f)));
+  } else {
+    ret.push_back(static_cast<char>(0xf0 | (c >> 18)));
+    ret.push_back(static_cast<char>(0x80 | ((c >> 12) & 0x3f)));
+    ret.push_back(static_cast<char>(0x80 | ((c >> 6) & 0x3f)));
+    ret.push_back(static_cast<char>(0x80 | (c & 0x3f)));
+  }
+}
+
+std::string MakeModifiedUTF8(const char* str, const char* ptr, uint32_t c) {
+  std::string ret;
+  while (true) {
+    ret.append(str, ptr - str);
+    str = ptr;
+    u8_write(ret, 0xd800 + ((c & 0xffff) >> 10));
+    u8_write(ret, 0xdc00 + (c & 0x3ff));
+    if (!*ptr) break;
+    do {
+      ptr = u8_read(ptr, c);
+      if (c > 0xffff)
+        break;
+    } while (*ptr);
+  }
+  return ret;
+}
+
+std::optional<std::string> MakeModifiedUTF8IfNeeded(const char* str) {
+  auto* ptr = str;
+  while (*ptr) {
+    uint32_t c;
+    ptr = u8_read(ptr, c);
+    if (c > 0xffff) {
+      return MakeModifiedUTF8(str, ptr, c);
+    }
+  }
+  return std::nullopt;
+}
+
+const char* splice(std::string& str, const char* start, const char* end, const char* insert, size_t size) {
+  auto pos = start - str.c_str();
+  str.replace(pos, end - start, insert, size);
+  return str.c_str() + pos + size;
+}
+
+void UnmodifyUTF8(std::string& str) {
+  auto* ptr = str.c_str();
+  while (*ptr) {
+    uint32_t u;
+    auto* next = u8_read(ptr, u);
+    if (u == 0) {
+      next = splice(str, ptr, next, "\0", 1);
+    } else if (u >= 0xd800 && u <= 0xdfff) {
+      uint32_t v;
+      next = u8_read(next, v);
+      u = 0x10000 | ((u - 0xd800) << 10) | (v - 0xdc00);
+      std::string tmp;
+      u8_write(tmp, u);
+      next = splice(str, ptr, next, tmp.data(), tmp.size());
+    }
+    ptr = next;
+  }
+}
+
 }  // namespace
 
 namespace jni {
@@ -132,14 +232,46 @@ std::string StringToUTF8(JNIEnv* env, const Ref<jstring>& str) {
   auto len = env->GetStringUTFLength(str.get());
   std::string ret(len, ' ');
   env->GetStringUTFRegion(str.get(), 0, len, ret.data());
-  // This returns modified UTF-8 encoding, don't care.
+  UnmodifyUTF8(ret);
   return ret;
 }
 
 LocalRef<jstring> UTF8ToString(JNIEnv* env, const std::string& str) {
+  auto ret = MakeModifiedUTF8IfNeeded(str.c_str());
+  if (ret.has_value()) {
+    return {env, env->NewStringUTF(ret->c_str())};
+  }
   return {env, env->NewStringUTF(str.c_str())};
 }
 
+LocalRef<jstring> UTF8ToString(JNIEnv* env, const char* str) {
+  if (str == nullptr) return nullptr;
+  auto ret = MakeModifiedUTF8IfNeeded(str);
+  if (ret.has_value()) {
+    return {env, env->NewStringUTF(ret->c_str())};
+  }
+  return {env, env->NewStringUTF(str)};
+}
+
+LocalRef<jbyteArray> VectorToByteArray(JNIEnv* env, const std::vector<uint8_t>& data) {
+  auto len = static_cast<jsize>(data.size());
+  auto ret = LocalRef<jbyteArray>(env, env->NewByteArray(len));
+  ABORT_IF_NULL(env, ret);
+  auto* ptr = reinterpret_cast<jbyte*>(env->GetPrimitiveArrayCritical(ret.get(), nullptr));
+  std::copy_n(data.data(), data.size(), ptr);
+  env->ReleasePrimitiveArrayCritical(ret.get(), ptr, JNI_COMMIT);
+  return ret;
+}
+
+std::vector<uint8_t> ByteArrayToVector(JNIEnv* env, const Ref<jbyteArray>& data) {
+  if (!data) return {};
+  auto len = env->GetArrayLength(data.get());
+  std::vector<uint8_t> ret(len);
+  static_assert(sizeof(jbyte) == sizeof(uint8_t));
+  env->GetByteArrayRegion(data.get(), 0, len, reinterpret_cast<jbyte*>(ret.data()));
+  return ret;
+}
+
 LocalRef<jobjectArray> CreateArray(JNIEnv* env, const Ref<jclass>& element_class, std::vector<LocalRef<jobject>> objects) {
   auto ret = LocalRef<jobjectArray>(env, env->NewObjectArray(static_cast<jsize>(objects.size()), element_class.get(), nullptr));
   ABORT_IF_NULL(env, ret);
diff --git a/libs/samba/src/main/cpp/jni.hpp b/libs/samba/src/main/cpp/jni.hpp
index 1729828..b9bdb69 100644
--- a/libs/samba/src/main/cpp/jni.hpp
+++ b/libs/samba/src/main/cpp/jni.hpp
@@ -2,6 +2,7 @@
 #define CLEVERSYNC_JNI_HPP
 
 #include <jni.h>
+#include <cstdint>
 #include <string>
 #include <vector>
 
@@ -186,6 +187,12 @@ std::string StringToUTF8(JNIEnv* env, const Ref<jstring>& str);
 
 LocalRef<jstring> UTF8ToString(JNIEnv* env, const std::string& str);
 
+LocalRef<jstring> UTF8ToString(JNIEnv* env, const char* str);
+
+LocalRef<jbyteArray> VectorToByteArray(JNIEnv* env, const std::vector<uint8_t>& data);
+
+std::vector<uint8_t> ByteArrayToVector(JNIEnv* env, const Ref<jbyteArray>& data);
+
 LocalRef<jobjectArray> CreateArray(JNIEnv* env, const Ref<jclass>& element_class, std::vector<LocalRef<jobject>> objects);
 
 namespace internal {