libssh2/TODO

Things TODO
===========

* Fix the numerous malloc+copy operations for sending data, see below for
  details

* make sure the windowing code adapts better to slow situations so that it
  doesn't then use as much memory as today. Possibly by an app-controllable
  "Window mode"?

* Introduce a function that can free data that is returned allocated from the
  lib, like when libssh2_session_last_error() is asked to return the string
  with 'want_buf' set to non-zero.

* Add more info to the man pages.

* Decrease the number of mallocs. Everywhere. Will get easier once the
  buffering improvements have been done.

* Use SO_NOSIGPIPE for Mac OS/BSD systems where MSG_NOSIGNAL doesn't
  exist/work

* Extend the test suite to actually test lots of aspects of libssh2

* Fix all compiler warnings (some can't be done without API changes)

* Expose error messages sent by the server

* Make SFTP transfers ask for and send several packages at once so that it
  doesn't have to send-waitforack-send-waitforack as much.

At next SONAME bump
===================

* stop using #defined macros as part of the official API. The macros should
  either be turned into real functions or discarded from the API.

* fix the parts of the API where object pointers and function pointers are
  mixed like libssh2_session_callback_set()

* remove the following functions from the API/ABI

  libssh2_base64_decode()
  libssh2_session_flag()
  libssh2_channel_handle_extended_data()
  libssh2_channel_receive_window_adjust()
  libssh2_poll()
  libssh2_poll_channel_read()
  libssh2_session_startup() (libssh2_session_handshake() is the replacement)

* Rename a few function:

  libssh2_hostkey_hash => libssh2_session_hostkey_hash
  libssh2_banner_set => libssh2_session_banner_set

* change 'int' to 'libssh2_socket_t' in the public API for sockets.

* Use 'size_t' for string lengths in all functions.

* Add a comment field to struct libssh2_knownhost.

* remove the existing libssh2_knownhost_add() function and rename
  libssh2_knownhost_addc to become the new libssh2_knownhost_add instead

* remove the existing libssh2_scp_send_ex() function and rename
  libssh2_scp_send64 to become the new libssh2_scp_send instead.

* remove the existing libssh2_knownhost_check() functin and rename
  libssh2_knownhost_checkp() to become the new libssh2_knownhost_check instead

Buffering Improvements
======================

compression

  - needs to ne able to take the input to compress from two pointers (with two
  sizes) and generate a single compressed output chunk

  - should also not allocate the compressed output buffer but use a single one
  within the session struct (as transport_write() will copy the data off from
  that buffer immediately anyway), or even better the transport_write()
  function could allocate a buffer to fix an uncompressed buffer as then the
  compression function can write its output directly into the allocated send
  buffer

  - should probably be split off into a separate compression and decompression
  function instead of a single unified as they are now, to make these changes
  easier

transport_write

  - should accept a "packet struct" input with separate pointers to headers
  and to payload (each of which may be allocated or not)

  - Separating the headers from the payload will greatly enhance our ability
  to use a fixed buffer within the session handle for the header part and
  provide the payload part as a mere pointer.

  - This function is used >30 times in the code.

  - If this function gets called with a total packet size that is larger than
  32K, it should create more than one SSH packet so that it keeps the largest
  one below 32K

channel_write

  - should not copy/allocate anything for the data, only create a header chunk
  and pass on the payload data to transport_write "pointed to"

sftp_write

  - should not copy/allocate anything for the data, only create a header chunk
  and pass on the payload data to channel_write "pointed to"