[datalogtool] Add datalogtool

This is a support tool for datalog file conversion (and eventually
download/remote datalog file management).

datalogtool/src/main/native/cpp/Sftp.h

@@ -0,0 +1,144 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#pragma once
+
+#include <libssh/libssh.h>
+#include <libssh/sftp.h>
+
+#include <stdexcept>
+#include <string>
+#include <string_view>
+#include <vector>
+
+#include <wpi/span.h>
+
+namespace sftp {
+
+struct Attributes {
+  Attributes() = default;
+  explicit Attributes(sftp_attributes&& attr);
+
+  std::string name;
+  uint32_t flags = 0;
+  uint8_t type = 0;
+  uint64_t size = 0;
+};
+
+/**
+ * This is the exception that will be thrown if something goes wrong.
+ */
+class Exception : public std::runtime_error {
+ public:
+  explicit Exception(const std::string& msg) : std::runtime_error{msg} {}
+  explicit Exception(sftp_session sftp);
+
+  int err = 0;
+};
+
+class File {
+ public:
+  File() = default;
+  explicit File(sftp_file&& handle) : m_handle{handle} {}
+  ~File();
+
+  Attributes Stat() const;
+
+  void SetNonblocking() { sftp_file_set_nonblocking(m_handle); }
+  void SetBlocking() { sftp_file_set_blocking(m_handle); }
+
+  using AsyncId = uint32_t;
+
+  size_t Read(void* buf, uint32_t count);
+  AsyncId AsyncReadBegin(uint32_t len) const;
+  size_t AsyncRead(void* data, uint32_t len, AsyncId id);
+  size_t Write(wpi::span<const uint8_t> data);
+
+  void Seek(uint64_t offset);
+  uint64_t Tell() const;
+  void Rewind();
+
+  void Sync();
+
+  std::string_view GetName() const { return m_handle->name; }
+  uint64_t GetOffset() const { return m_handle->offset; }
+  bool IsEof() const { return m_handle->eof; }
+  bool IsNonblocking() const { return m_handle->nonblocking; }
+
+ private:
+  sftp_file m_handle{nullptr};
+};
+
+/**
+ * This class is a C++ implementation of the SshSessionController in
+ * wpilibsuite/deploy-utils. It handles connecting to an SSH server, running
+ * commands, and transferring files.
+ */
+class Session {
+ public:
+  /**
+   * Constructs a new session controller.
+   *
+   * @param host The hostname of the server to connect to.
+   * @param port The port that the sshd server is operating on.
+   * @param user The username to login as.
+   * @param pass The password for the given username.
+   */
+  Session(std::string_view host, int port, std::string_view user,
+          std::string_view pass);
+
+  /**
+   * Destroys the controller object. This also disconnects the session from the
+   * server.
+   */
+  ~Session();
+
+  /**
+   * Opens the SSH connection to the given host.
+   */
+  void Connect();
+
+  /**
+   * Disconnects the SSH connection.
+   */
+  void Disconnect();
+
+  /**
+   * Reads directory entries
+   *
+   * @param path remote path
+   * @return vector of file attributes
+   */
+  std::vector<Attributes> ReadDir(const std::string& path);
+
+  /**
+   * Unlinks (deletes) a file.
+   *
+   * @param filename filename
+   */
+  void Unlink(const std::string& filename);
+
+  /**
+   * Opens a file.
+   *
+   * @param filename filename
+   * @param accesstype O_RDONLY, O_WRONLY, or O_RDWR, combined with O_CREAT,
+   *                   O_EXCL, or O_TRUNC
+   * @param mode permissions to use if a new file is created
+   * @return File
+   */
+  File Open(const std::string& filename, int accesstype, mode_t mode);
+
+ private:
+  ssh_session m_session{nullptr};
+  sftp_session m_sftp{nullptr};
+  std::string m_host;
+
+  int m_port;
+
+  std::string m_username;
+  std::string m_password;
+};
+
+}  // namespace sftp