This patch series marks the  '4' in the countdown to speed up rebase -i
by implementing large parts in C. It is based on the `libify-sequencer`
patch series that I submitted last week.

The patches in this series merely prepare the sequencer code for the
next patch series that actually teaches the sequencer to run an
interactive rebase.

The reason to split these two patch series is simple: to keep them at a
sensible size.

The two patch series after that are much smaller: a two-patch "series"
that switches rebase -i to use the sequencer (except with --root or
--preserve-merges), and a couple of patches to move several pretty
expensive script processing steps to C (think: autosquash).

The end game of this patch series is a git-rebase--helper that makes
rebase -i 5x faster on Windows (according to t/perf/p3404). Travis says
that even MacOSX and Linux benefit (4x and 3x, respectively).

I have been working on this since early February, whenever time allowed,
and it is time to put it into the users' hands. To that end, I will most
likely submit the remaining three patch series in the next two days, and
integrate the whole shebang into Git for Windows 2.10.0.

Therefore I would be most grateful for every in-depth review.

Changes vs v1:

- clarified why the code refactoring into the short_commit_name()
  function is desirable.

- fixed a typo in a commit message (s/se/so/).

- removed a bogus call to read_and_refresh_cache(opts) that was added
  to sequencer_rollback() by mistake.

- clarified in the commit message why the TODO_LIST_INIT macro does not
  assign all-zeroes.

- converted IS_REBASE_I() into an inline function.

- clarified the comment about retaining author metadata when calling
  sequencer_commit() in rebase -i mode.

- simplified TODO_LIST_INIT and REPLAY_OPTS_INIT.

- added an example how to use sequencer_entrust() to the commit message
  introducing it.

- the gpg_sign option's value is now also entrusted to the sequencer
  (i.e. it is released in sequencer_remove_state()).

- renamed the "set_me_free_after_use" to "to_free". Since that is still
  not a self-explanatory name, add a comment to the function
  declaration.

- clarified in the "completely revamped todo parsing" commit message
  that the main benefit of the early parsing is for rebase -i.

- start the `enum todo_command` with TODO_PICK that is explicitly
  assigned the value 0.

- an error was marked as translatable.

- converted one forgotten git_path_todo_file() to use
  get_todo_path(opts) instead.

- fixed numbering of "malformed instruction sheet"s after removing one.

- reintroduced the overzealous assumption that todo scripts can only
  perform revert commands during `git revert` and pick commands during
  `git cherry-pick`. This overzealous assumption is *still* disabled in
  rebase -i mode, of course.

- clarified in the commit message why we call the field "arg", not
  "oneline", and fixed the description that claimed that we store the
  end offset (we store the length instead).

- clarified in the commit message of "allow editing the commit message
  on a case-by-case basis" that we are talking about the
  sequencer_commit() function, and how things were done previously.

- some grammar touch-ups.

- marked a couple of error messages for translation.

- explicitly assign the first todo_command the value 0, so that we can
  be certain that the array of command strings matches up.

- removed code to skip CR/LF at the end of line after reading with
  read_oneliner(): That function already ensures that.

- ensured that the todo_list is released even when reading/parsing fails.

- replaced an error(..., strerror()) call with an error_errno(...) one.

- clarified in the commit message why the new todo_list maintains the
  script as an array instead of a linked list.

- renamed the append_todo() function into append_new_todo(), to explain
  better what the function does and why it does not take the values as
  parameters that should populate the new todo_item.

- marked action_name() for translation.

- surrounded all file names in error messages in sequencer.c with single
  quotes, for consistency.

- removed a bogus hint for translators that asked them to translate
  commands of the git-rebase-todo file (or cherry-pick's equivalent).

- turned capitals after semicolons to lower-case.

Johannes Schindelin (25):
  sequencer: use static initializers for replay_opts
  sequencer: use memoized sequencer directory path
  sequencer: avoid unnecessary indirection
  sequencer: future-proof remove_sequencer_state()
  sequencer: allow the sequencer to take custody of malloc()ed data
  sequencer: release memory that was allocated when reading options
  sequencer: future-proof read_populate_todo()
  sequencer: completely revamp the "todo" script parsing
  sequencer: avoid completely different messages for different actions
  sequencer: get rid of the subcommand field
  sequencer: refactor the code to obtain a short commit name
  sequencer: remember the onelines when parsing the todo file
  sequencer: prepare for rebase -i's commit functionality
  sequencer: introduce a helper to read files written by scripts
  sequencer: prepare for rebase -i's GPG settings
  sequencer: allow editing the commit message on a case-by-case basis
  sequencer: support amending commits
  sequencer: support cleaning up commit messages
  sequencer: remember do_recursive_merge()'s return value
  sequencer: left-trim lines read from the script
  sequencer: refactor write_message()
  sequencer: remove overzealous assumption in rebase -i mode
  sequencer: mark action_name() for translation
  sequencer: quote filenames in error messages
  sequencer: remove bogus hint for translators

 builtin/commit.c |   2 +-
 builtin/revert.c |  42 ++--
 sequencer.c      | 632 +++++++++++++++++++++++++++++++++++++------------------
 sequencer.h      |  31 +--
 4 files changed, 468 insertions(+), 239 deletions(-)

Submitted-As: https://public-inbox.org/git/cover.1473590966.git.johannes.schindelin@gmx.de
In-Reply-To: https://public-inbox.org/git/cover.1472457609.git.johannes.schindelin@gmx.de