add patch downloader

src/PatchDownloadSession.hh

@@ -0,0 +1,61 @@
+#pragma once
+
+#include <asio.hpp>
+#include <map>
+#include <memory>
+#include <phosg/Filesystem.hh>
+#include <string>
+#include <unordered_map>
+#include <unordered_set>
+#include <vector>
+
+#include "Channel.hh"
+#include "CommandFormats.hh"
+#include "PSOEncryption.hh"
+#include "PSOProtocol.hh"
+
+class PatchDownloadSession {
+public:
+  PatchDownloadSession(
+      std::shared_ptr<asio::io_context> io_context,
+      const std::string& remote_host,
+      uint16_t remote_port,
+      const std::string& output_dir,
+      Version version,
+      const std::string& username,
+      const std::string& password,
+      const std::string& email,
+      bool show_command_data);
+  PatchDownloadSession(const PatchDownloadSession&) = delete;
+  PatchDownloadSession(PatchDownloadSession&&) = delete;
+  PatchDownloadSession& operator=(const PatchDownloadSession&) = delete;
+  PatchDownloadSession& operator=(PatchDownloadSession&&) = delete;
+  virtual ~PatchDownloadSession() = default;
+
+  asio::awaitable<void> run();
+
+protected:
+  // Config (must be set by caller)
+  std::string remote_host;
+  uint16_t remote_port;
+  std::string output_dir;
+  Version version;
+  std::string username;
+  std::string password;
+  std::string email;
+  bool show_command_data;
+
+  // State (set during session)
+  phosg::PrefixedLogger log;
+  std::shared_ptr<asio::io_context> io_context;
+  std::shared_ptr<Channel> channel;
+  std::vector<std::string> dir_path;
+  std::unique_ptr<FILE, void (*)(FILE*)> current_file;
+  size_t current_file_bytes_remaining = 0;
+  std::vector<C_FileInformation_Patch_0F> pending_checksum_results;
+
+  static void check_path_token(const std::string& token);
+  std::string resolve_filename(const std::string& filename) const;
+
+  asio::awaitable<void> on_message(Channel::Message& msg);
+};