This is mostly lifted from earlier series by Dan Zwell, but updated to
use "git config --get-color" and "git config --get-colorbool" to make it
simpler and more consistent with commands written in C.

A new configuration color.interactive variable is like color.diff and
color.status, and controls if "git-add -i" uses color.

A set of configuration variables, color.interactive.<slot>, are used to
define what color is used for the prompt, header, and help text.

For perl scripts, Git.pm provides $repo->get_color() method, which takes
the slot name and the default color, and returns the terminal escape
sequence to color the output text.  $repo->get_colorbool() method can be
used to check if color is set to be used for a given operation.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NJunio C Hamano <gitster@pobox.com>

These changes make the automatic prefix highlighting work with the "Add
untracked" subcommand in git-add--interactive by explicitly handling
arrays, hashes and strings internally (previously only arrays and hashes
were handled).

In addition, prefixes which have special meaning for list_and_choose
(things like "*" for "all" and "-" for "deselect) are explicitly
excluded (highlighting these prefixes would be misleading).
Signed-off-by: NWincent Colaiuta <win@wincent.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The user interface provided by the command loop in git-add--interactive
gives the impression that subcommands can only be launched by entering
an integer identifier from 1 through 8.

A "hidden" feature is that any string can be entered, and a regex search
anchored at the beginning of the string is used to find the uniquely
matching option.

This patch makes this feature a little more obvious by highlighting the
first character of each subcommand (for example "patch" is displayed as
"[p]atch").

A new function is added to detect the shortest unique prefix and this
is used to decide what to highlight. Highlighting is also applied when
choosing files.

In the case where the common prefix may be unreasonably large
highlighting is omitted; in this patch the soft limit (above which the
highlighting will be omitted for a particular item) is 0 (in other words,
there is no soft limit) and the hard limit (above which highlighting will
be omitted for all items) is 3, but this can be tweaked.

The actual highlighting is done by the highlight_prefix function, which
will enable us to implement ANSI color code-based highlighting (most
likely using underline or boldface) in the future.
Signed-off-by: NWincent Colaiuta <win@wincent.com>
Acked-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When the "--patch" option is supplied, the patch_update_cmd() function is
called bypassing the main_loop() and exits.

Seeing as builtin-add is the only caller of git-add--interactive we can
impose a strict requirement on the format of the arguments to avoid
possible ambiguity: an "--" argument must be used whenever any pathspecs
are passed, both with the "--patch" option and without it.
Signed-off-by: NWincent Colaiuta <win@wincent.com>

This allows more than one files from the list to be chosen from
the patch subcommand instead of going through the file one by
one.

This also updates the "list-and-choose" UI for usability.  When
the prompt ends with ">>", if you type '*' to choose all
choices, the prompt immediately returns the choice without
requiring an extra empty line to confirm the selection.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Implement Junio's suggestion that git-add--interactive should reproduce the
path-limiting semantics of non-interactive git-add.

In otherwords, if "git add -i" (unrestricted) shows paths from a set A,
"git add -i paths..." should show paths from a subset of the set A and that
subset should be defined with the existing ls-files pathspec semantics.
Signed-off-by: NWincent Colaiuta <win@wincent.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Split patch_update_cmd into two functions, one to prompt the user for
a path to patch and another to do the actual work given that file path.
This lays the groundwork for a future commit which will teach
git-add--interactive to accept a path parameter and jump directly to
the patch subcommand for that path, bypassing the interactive prompt.
Signed-off-by: NWincent Colaiuta <win@wincent.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This provides a way for scripts to get at the new standard exclude
function.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NJean-Luc Herren <jlh@gmx.ch>
Signed-off-by: NLars Hjemli <hjemli@gmail.com>
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

The unified diff format allows one-line ranges to be abbreviated
by omiting the size.  The hunk header "@@ -10,1 +10,1 @@" can be
expressed as "@@ -10 +10 @@", but this wasn't properly parsed in
all cases.

Such abbreviated hunk headers are generated when a one-line change
(add, remove or modify) appears without context; for example
because the file is a one-liner itself or because GIT_DIFF_OPTS
was set to '-u0'.  If the user then runs 'git add -i' and enters
the 'patch' command for that file, perl complains about undefined
variables.
Signed-off-by: NJean-Luc Herren <jlh@gmx.ch>
Signed-off-by: NLars Hjemli <hjemli@gmail.com>
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

1) Previously, any menu would cause a perl error when entered '0',
   which is never a valid option.

2) Entering a bogus choice (like 998 or 4-2) surprisingly caused
   the same behavior as if the user had just hit 'enter', which
   means to carry out the selected action on the selected items.
   Entering such bogus input is now a no-op and the sub-menu
   doesn't exit.
Signed-off-by: NJean-Luc Herren <jlh@gmx.ch>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Hitting Ctrl-D (EOF) is a common way to exit shell-like tools.
When in a sub-menu it will still behave as if an empty line had
been entered, carrying out the action on the selected items and
returning to the previous menu.
Signed-off-by: NJean-Luc Herren <jlh@gmx.ch>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

It wont work for arguments with special characters (like ", : or *).
It is generally not possible on Windows, so I didn't even try.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Earlier, when a path that was removed from the working tree was
chosen for update subcommand, you got an error like this:

    error: git-resolve.sh: does not exist and --remove not passed
    fatal: Unable to process file git-resolve.sh
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This adds hunk splitting and recounting the patch lines.  The
'patch' subcommand now allows you to split a large hunk at
context lines in the middle.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

A script to be driven when the user says "git add --interactive"
is introduced.

When it is run, first it runs its internal 'status' command to
show the current status, and then goes into its internactive
command loop.

The command loop shows the list of subcommands available, and
gives a prompt "What now> ".  In general, when the prompt ends
with a single '>', you can pick only one of the choices given
and type return, like this:

    *** Commands ***
      1: status       2: update       3: revert       4: add untracked
      5: patch        6: diff         7: quit         8: help
    What now> 1

You also could say "s" or "sta" or "status" above as long as the
choice is unique.

The main command loop has 6 subcommands (plus help and quit).

 * 'status' shows the change between HEAD and index (i.e. what
   will be committed if you say "git commit"), and between index
   and working tree files (i.e. what you could stage further
   before "git commit" using "git-add") for each path.  A sample
   output looks like this:

              staged     unstaged path
     1:       binary      nothing foo.png
     2:     +403/-35        +1/-1 git-add--interactive.perl

   It shows that foo.png has differences from HEAD (but that is
   binary so line count cannot be shown) and there is no
   difference between indexed copy and the working tree
   version (if the working tree version were also different,
   'binary' would have been shown in place of 'nothing').  The
   other file, git-add--interactive.perl, has 403 lines added
   and 35 lines deleted if you commit what is in the index, but
   working tree file has further modifications (one addition and
   one deletion).

 * 'update' shows the status information and gives prompt
   "Update>>".  When the prompt ends with double '>>', you can
   make more than one selection, concatenated with whitespace or
   comma.  Also you can say ranges.  E.g. "2-5 7,9" to choose
   2,3,4,5,7,9 from the list.  You can say '*' to choose
   everything.

   What you chose are then highlighted with '*', like this:

              staged     unstaged path
     1:       binary      nothing foo.png
   * 2:     +403/-35        +1/-1 git-add--interactive.perl

   To remove selection, prefix the input with - like this:

        Update>> -2

   After making the selection, answer with an empty line to
   stage the contents of working tree files for selected paths
   in the index.

 * 'revert' has a very similar UI to 'update', and the staged
   information for selected paths are reverted to that of the
   HEAD version.  Reverting new paths makes them untracked.

 * 'add untracked' has a very similar UI to 'update' and
   'revert', and lets you add untracked paths to the index.

 * 'patch' lets you choose one path out of 'status' like
   selection.  After choosing the path, it presents diff between
   the index and the working tree file and asks you if you want
   to stage the change of each hunk.  You can say:

        y - add the change from that hunk to index
        n - do not add the change from that hunk to index
        a - add the change from that hunk and all the rest to index
        d - do not the change from that hunk nor any of the rest to index
        j - do not decide on this hunk now, and view the next
            undecided hunk
        J - do not decide on this hunk now, and view the next hunk
        k - do not decide on this hunk now, and view the previous
            undecided hunk
        K - do not decide on this hunk now, and view the previous hunk

   After deciding the fate for all hunks, if there is any hunk
   that was chosen, the index is updated with the selected hunks.

 * 'diff' lets you review what will be committed (i.e. between
   HEAD and index).

This is still rough, but does everything except a few things I
think are needed.

 * 'patch' should be able to allow splitting a hunk into
   multiple hunks.

 * 'patch' does not adjust the line offsets @@ -k,l +m,n @@
   in the hunk header.  This does not have major problem in
   practice, but it _should_ do the adjustment.

 * It does not have any explicit support for a merge in
   progress; it may not work at all.
Signed-off-by: NJunio C Hamano <junkio@cox.net>