Session.h

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#ifndef joedb_ssh_Session_declared
#define joedb_ssh_Session_declared
 
#include "joedb/error/assert.h"
 
#include <string>
#include <libssh/libssh.h>
 
namespace joedb
{
 namespace ssh
 {
  /// @ingroup concurrency
  class Session_Allocation
  {
   protected:
    const ssh_session session;
 
   public:
    Session_Allocation(): session(ssh_new())
    {
     JOEDB_RELEASE_ASSERT(session);
    }
 
    Session_Allocation(const Session_Allocation &) = delete;
    Session_Allocation &operator=(const Session_Allocation &) = delete;
 
    ssh_session get() const
    {
     return session;
    }
 
    void check_result(int result) const
    {
     if (result != SSH_OK)
      throw Exception(ssh_get_error(session));
    }
 
    ~Session_Allocation()
    {
     ssh_free(session);
    }
  };
 
  /// @ingroup concurrency
  class Session_Connection: public Session_Allocation
  {
   public:
    Session_Connection
    (
     const char *user,
     const char *host,
     unsigned port,
     int verbosity
    )
    {
     ssh_options_set(session, SSH_OPTIONS_HOST, host);
     ssh_options_set(session, SSH_OPTIONS_USER, user);
     ssh_options_set(session, SSH_OPTIONS_PORT, &port);
     ssh_options_set(session, SSH_OPTIONS_LOG_VERBOSITY, &verbosity);
 
     {
      const int no_delay = 1;
      ssh_options_set(session, SSH_OPTIONS_NODELAY, &no_delay);
     }
 
     check_result(ssh_connect(session));
    }
 
    ~Session_Connection()
    {
     ssh_disconnect(session);
    }
  };
 
  /// @ingroup concurrency
  class Imported_Key
  {
   private:
    ssh_key key;
 
   public:
    Imported_Key(const char *b64_key, const char *passphrase): key(nullptr)
    {
     ssh_pki_import_privkey_base64
     (
      b64_key,
      passphrase,
      nullptr,
      nullptr,
      &key
     );
 
     JOEDB_RELEASE_ASSERT(key);
    }
 
    Imported_Key(const Imported_Key &) = delete;
    Imported_Key &operator=(const Imported_Key &) = delete;
 
    ssh_key get() const
    {
     return key;
    }
 
    ~Imported_Key()
    {
     ssh_key_free(key);
    }
  };
 
  /// @ingroup concurrency
  class Session: public Session_Connection
  {
   public:
    Session
    (
     const std::string &user,
     const std::string &host,
     const unsigned port,
     const int verbosity,
     const char * const b64_key = nullptr,
     const char * const passphrase = nullptr
    ):
     Session_Connection(user.c_str(), host.c_str(), port, verbosity)
    {
     if (b64_key)
     {
      const Imported_Key key(b64_key, passphrase);
      check_result(ssh_userauth_publickey(session, user.c_str(), key.get()));
     }
     else
     {
      check_result(ssh_userauth_publickey_auto(session, nullptr, passphrase));
     }
    }
  };
 }
}
 
#endif