Add the ability to add torrents with base64 data URLs

include/core/download_factory.h

@@ -109,9 +109,11 @@ class DownloadFactory {
 };
 
 bool
-is_network_uri(const std::string& uri);
+is_data_uri(const std::string& uri);
 bool
 is_magnet_uri(const std::string& uri);
+bool
+is_network_uri(const std::string& uri);
 
 }
 

src/core/download_factory.cc

@@ -30,6 +30,17 @@
 
 namespace core {
 
+bool
+is_data_uri(const std::string& uri) {
+  return std::strncmp(uri.c_str(), "data:", 5) == 0 &&
+         uri.find("base64,", 5) != std::string::npos;
+}
+
+bool
+is_magnet_uri(const std::string& uri) {
+  return std::strncmp(uri.c_str(), "magnet:?", 8) == 0;
+}
+
 bool
 is_network_uri(const std::string& uri) {
   return std::strncmp(uri.c_str(), "http://", 7) == 0 ||
@@ -56,11 +67,6 @@ download_factory_add_stream(torrent::Object* root,
   return true;
 }
 
-bool
-is_magnet_uri(const std::string& uri) {
-  return std::strncmp(uri.c_str(), "magnet:?", 8) == 0;
-}
-
 DownloadFactory::DownloadFactory(Manager* m)
   : m_manager(m) {
 

src/core/manager.cc

@@ -41,6 +41,60 @@
 
 namespace core {
 
+constexpr static char padCharacter = '=';
+static std::string
+base64Decode(const std::string_view& input) {
+  if (input.length() % 4) // Sanity check
+    throw torrent::input_error("Invalid base64.");
+  size_t padding = 0;
+  if (input.length()) {
+    if (input[input.length() - 1] == padCharacter)
+      padding++;
+    if (input[input.length() - 2] == padCharacter)
+      padding++;
+  }
+  // Setup a vector to hold the result
+  std::string decodedBytes;
+  decodedBytes.reserve(((input.length() / 4) * 3) - padding);
+  long                             temp   = 0; // Holds decoded quanta
+  std::string_view::const_iterator cursor = input.begin();
+  while (cursor < input.end()) {
+    for (size_t quantumPosition = 0; quantumPosition < 4; quantumPosition++) {
+      temp <<= 6;
+      if (*cursor >= 0x41 && *cursor <= 0x5A) // This area will need tweaking if
+        temp |= *cursor - 0x41; // you are using an alternate alphabet
+      else if (*cursor >= 0x61 && *cursor <= 0x7A)
+        temp |= *cursor - 0x47;
+      else if (*cursor >= 0x30 && *cursor <= 0x39)
+        temp |= *cursor + 0x04;
+      else if (*cursor == 0x2B)
+        temp |= 0x3E; // change to 0x2D for URL alphabet
+      else if (*cursor == 0x2F)
+        temp |= 0x3F;                   // change to 0x5F for URL alphabet
+      else if (*cursor == padCharacter) // pad
+      {
+        switch (input.end() - cursor) {
+          case 1: // One pad character
+            decodedBytes.push_back((temp >> 16) & 0x000000FF);
+            decodedBytes.push_back((temp >> 8) & 0x000000FF);
+            return decodedBytes;
+          case 2: // Two pad characters
+            decodedBytes.push_back((temp >> 10) & 0x000000FF);
+            return decodedBytes;
+          default:
+            throw torrent::input_error("Invalid padding in base64.");
+        }
+      } else
+        throw torrent::input_error("Invalid character in base64.");
+      cursor++;
+    }
+    decodedBytes.push_back((temp >> 16) & 0x000000FF);
+    decodedBytes.push_back((temp >> 8) & 0x000000FF);
+    decodedBytes.push_back((temp)&0x000000FF);
+  }
+  return decodedBytes;
+}
+
 void
 Manager::push_log(const char* msg) {
   m_log_important->lock_and_push_log(msg, strlen(msg), 0);
@@ -364,7 +418,7 @@ Manager::try_create_download(const std::string&       uri,
                              const command_list_type& commands) {
   // If the path was attempted loaded before, skip it.
   if ((flags & create_tied) && !(flags & create_raw_data) &&
-      !is_network_uri(uri) && !is_magnet_uri(uri) &&
+      !is_network_uri(uri) && !is_magnet_uri(uri) && !is_data_uri(uri) &&
       !file_status_cache()->insert(uri, flags & create_throw))
     return;
 
@@ -379,10 +433,19 @@ Manager::try_create_download(const std::string&       uri,
   f->set_immediate(flags & create_throw);
   f->slot_finished([f]() { delete f; });
 
-  if (flags & create_raw_data)
+  if (flags & create_raw_data) {
     f->load_raw_data(uri);
-  else
+  } else if (is_data_uri(uri)) {
+    const unsigned long start = uri.find("base64,", 5) + 7;
+    if (start >= uri.size()) {
+      throw torrent::input_error("Empty base64.");
+    }
+
+    f->load_raw_data(base64Decode(std::string_view(uri.c_str() + start)));
+    f->variables()["tied_to_file"] = (int64_t)0;
+  } else {
     f->load(uri);
+  }
 
   f->commit();
 }