Most users seem to like having colors enabled, and colors can help
beginners to understand the output of some commands (e.g. notice
immediately the boundary between commits in the output of "git log").

Many tutorials tell the users to set color.ui=auto as a very first step,
which tend to indicate that color.ui=none is not the recommanded value,
hence should not be the default.

These tutorials would benefit from skipping this step and starting the
real Git manipulations earlier. Other beginners do not know about
color.ui=auto, and may not discover it by themselves, hence live with
black&white outputs while they may have preferred colors.

A few people (e.g. color-blind) prefer having no colors, but they can
easily set color.ui=never for this (and googling "disable colors in git"
already tells them how to do so), but this needs not occupy space in
beginner-oriented documentations.

A transition period with Git emitting a warning when color.ui is unset
would be possible, but the discomfort of having the warning seems
superior to the benefit: users may be surprised by the change, but not
harmed by it.

The default value is changed, and the documentation is reworded to
mention "color.ui=false" first, since the primary use of color.ui after
this change is to disable colors, not to enable it.
Signed-off-by: NMatthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

All of the "do we want color" flags default to -1 to
indicate that we don't have any color configured. This value
is handled in one of two ways:

  1. In porcelain, we check early on whether the value is
     still -1 after reading the config, and set it to the
     value of color.ui (which defaults to 0).

  2. In plumbing, it stays untouched as -1, and want_color
     defaults it to off.

This works fine, but means that every porcelain has to check
and reassign its color flag. Now that want_color gives us a
place to put this check in a single spot, we can do that,
simplifying the calling code.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The diff config callback is split into two functions: one
which loads "ui" config, and one which loads "basic" config.
The former chains to the latter, as the diff UI config is a
superset of the plumbing config.

The color.diff variable is only loaded in the UI config.
However, the basic config actually chains to
git_color_default_config, which loads color.ui. This doesn't
actually cause any bugs, because the plumbing diff code does
not actually look at the value of color.ui.

However, it is somewhat nonsensical, and it makes it
difficult to refactor the color code. It probably came about
because there is no git_color_config to load only color
config, but rather just git_color_default_config, which
loads color config and chains to git_default_config.

This patch splits out the color-specific portion of
git_color_default_config so that the diff UI config can call
it directly. This is perhaps better explained by the
chaining of callbacks. Before we had:

  git_diff_ui_config
    -> git_diff_basic_config
      -> git_color_default_config
        -> git_default_config

Now we have:

  git_diff_ui_config
    -> git_color_config
    -> git_diff_basic_config
      -> git_default_config
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When we read a color value either from a config file or from
the command line, we use git_config_colorbool to convert it
from the tristate always/never/auto into a single yes/no
boolean value.

This has some timing implications with respect to starting
a pager.

If we start (or decide not to start) the pager before
checking the colorbool, everything is fine. Either isatty(1)
will give us the right information, or we will properly
check for pager_in_use().

However, if we decide to start a pager after we have checked
the colorbool, things are not so simple. If stdout is a tty,
then we will have already decided to use color. However, the
user may also have configured color.pager not to use color
with the pager. In this case, we need to actually turn off
color. Unfortunately, the pager code has no idea which color
variables were turned on (and there are many of them
throughout the code, and they may even have been manipulated
after the colorbool selection by something like "--color" on
the command line).

This bug can be seen any time a pager is started after
config and command line options are checked. This has
affected "git diff" since 89d07f75 (diff: don't run pager if
user asked for a diff style exit code, 2007-08-12). It has
also affect the log family since 1fda91b5 (Fix 'git log'
early pager startup error case, 2010-08-24).

This patch splits the notion of parsing a colorbool and
actually checking the configuration. The "use_color"
variables now have an additional possible value,
GIT_COLOR_AUTO. Users of the variable should use the new
"want_color()" wrapper, which will lazily determine and
cache the auto-color decision.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Usually this function figures out for itself whether stdout
is a tty. However, it has an extra parameter just to allow
git-config to override the auto-detection for its
--get-colorbool option.

Instead of an extra parameter, let's just use a global
variable. This makes calling easier in the common case, and
will make refactoring the colorbool code much simpler.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This also adds the new colors to show-branch that were added a while
back for graph output.
Signed-off-by: NDan McGee <dpmcgee@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Introduce status_printf{,_ln,_more} wrapper functions around
color_vfprintf() which take care of adding "#" to the beginning of
status lines automatically.  The semantics:

 - status_printf() is just like color_fprintf() but it adds a "# "
   at the beginning of each line of output;

 - status_printf_ln() is a convenience function that additionally
   adds "\n" at the end;

 - status_printf_more() is a variant of status_printf() used to
   continue lines that have already started.  It suppresses the "#" at
   the beginning of the first line.
Helped-by: NJunio C Hamano <gitster@pobox.com>
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Introduce status_printf{,_ln,_more} wrapper functions around
color_vfprintf() which take care of adding "#" to the beginning of
status lines automatically.  The semantics:

 - status_printf() is just like color_fprintf() but it adds a "# "
   at the beginning of each line of output;

 - status_printf_ln() is a convenience function that additionally
   adds "\n" at the end;

 - status_printf_more() is a variant of status_printf() used to
   continue lines that have already started.  It suppresses the "#" at
   the beginning of the first line.
Helped-by: NJunio C Hamano <gitster@pobox.com>
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This gives it the same behavior as we had prior to 1d282327
(status: show branchname with a configurable color).

To do this we need the concept of a "NIL" color, which is
provided by color.[ch]. The implementation is very simple;
in particular, there are no precautions taken against code
accidentally printing the NIL. This should be fine in
practice because:

  1. You can't input a NIL color in the config, so it must
     come from the in-code defaults. Which means it is up
     the client code to handle the NILs it defines.

  2. If we do ever print a NIL, it will be obvious what the
     problem is, and the bug can be fixed.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This teaches the --color-words engine a more general interface that
supports two new modes:

* --word-diff=plain, inspired by the 'wdiff' utility (most similar to
  'wdiff -n <old> <new>'): uses delimiters [-removed-] and {+added+}

* --word-diff=porcelain, which generates an ad-hoc machine readable
  format:
  - each diff unit is prefixed by [-+ ] and terminated by newline as
    in unified diff
  - newlines in the input are output as a line consisting only of a
    tilde '~'

Both of these formats still support color if it is enabled, using it
to highlight the differences.  --color-words becomes a synonym for
--word-diff=color, which is the color-only format.  Also adds some
compatibility/convenience options.

Thanks to Junio C Hamano and Miles Bader for good ideas.
Signed-off-by: NThomas Rast <trast@student.ethz.ch>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

In configuration files (and "git config --color" command line), we
supported one and only one attribute after foreground and background
color.  Accept combinations of attributes, e.g.

    [diff.color]
            old = red reverse bold
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Make git-branch, git-show-branch, git-grep, and all the diff-based
programs accept an optional argument <when> for --color.  The argument
is a colorbool: "always", "never", or "auto".  If no argument is given,
"always" is used;  --no-color is an alias for --color=never.  This makes
the command-line interface consistent with other GNU tools, such as `ls'
and `grep', and with the git-config color options.  Note that, without
an argument, --color and --no-color work exactly as before.

To implement this, two internal changes were made:

1. Allow the first argument of git_config_colorbool() to be NULL,
   in which case it returns -1 if the argument isn't "always", "never",
   or "auto".

2. Add OPT_COLOR_FLAG(), OPT__COLOR(), and parse_opt_color_flag_cb()
   to the option parsing library.  The callback uses
   git_config_colorbool(), so color.h is now a dependency
   of parse-options.c.
Signed-off-by: NMark Lodato <lodatom@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Remove the literal ANSI escape sequences and replace them by readable
constants.
Signed-off-by: NArjen Laarhoven <arjen@yaph.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Commit 5ef8d77a implemented color_parse_mem, a function for
parsing colors from a non-NUL-terminated string, by simply
allocating a new NUL-terminated string and calling
color_parse. This had a small but measurable speed impact on
a user format that used the advanced color parsing. E.g.,

  # uses quick parsing
  $ time ./git log --pretty=tformat:'%Credfoo%Creset' >/dev/null
  real    0m0.673s
  user    0m0.652s
  sys     0m0.016s

  # uses color_parse_mem
  $ time ./git log --pretty=tformat:'%C(red)foo%C(reset)' >/dev/null
  real    0m0.692s
  user    0m0.660s
  sys     0m0.032s

This patch implements color_parse_mem as the primary
function, with color_parse as a wrapper for strings. This
gives comparable timings to the first case above.

Original patch by René. Commit message and debugging by Jeff
King.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

We have very featureful color-parsing routines which are
used for color.diff.* and other options. Let's make it
easier to use those routines from other parts of the code.

This patch adds a color_parse_mem() helper function which
takes a length-bounded string instead of a NUL-terminated
one. While the helper is only a few lines long, it is nice
to abstract this out so that:

 - callers don't forget to free() the temporary buffer

 - right now, it is implemented in terms of color_parse().
   But it would be more efficient to reverse this and
   implement color_parse in terms of color_parse_mem.

This also changes the error string for an invalid color not
to mention the word "config", since it is not always
appropriate (and when it is, the context is obvious since
the offending config variable is given).

Finally, while we are in the area, we clean up the parameter
names in the declaration of color_parse; the var and value
parameters were reversed from the actual implementation.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

We have to set the color before every line and reset it before every
newline.  Add a function color_fwrite_lines() which does that for us.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

git_config() only had a function parameter, but no callback data
parameter.  This assumes that all callback functions only modify
global variables.

With this patch, every callback gets a void * parameter, and it is hoped
that this will help the libification effort.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NMatthias Kestenholz <mk@spinlock.ch>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Numeric color only worked if it was at end of line.
Noticed by Chris Larson <clarson@kergoth.com>.
Signed-off-by: NTimo Hirvonen <tihirvon@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When deciding whether or not to turn on automatic color
support, git_config_colorbool checks whether stdout is a
tty. However, because we run a pager, if stdout is not a
tty, we must check whether it is because we started the
pager. This used to be done by checking the pager_in_use
variable.

This variable was set only when the git program being run
started the pager; there was no way for an external program
running git indicate that it had already started a pager.
This patch allows a program to set GIT_PAGER_IN_USE to a
true value to indicate that even though stdout is not a tty,
it is because a pager is being used.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This adds an option to help scripts find out color settings from
the configuration file.

    git config --get-colorbool color.diff

inspects color.diff variable, and exits with status 0 (i.e. success) if
color is to be used.  It exits with status 1 otherwise.

If a script wants "true"/"false" answer to the standard output of the
command, it can pass an additional boolean parameter to its command
line, telling if its standard output is a terminal, like this:

    git config --get-colorbool color.diff true

When called like this, the command outputs "true" to its standard output
if color is to be used (i.e. "color.diff" says "always", "auto", or
"true"), and "false" otherwise.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Too many people got burned by setting color.diff and color.status to
true when they really should have set it to "auto".

This makes only "always" to do the unconditional colorization, and
change the meaning of "true" to the same as "auto": colorize only when
we are talking to a terminal.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Still defaults to stdout, but you can now override wt_status.fp after
calling wt_status_prepare().
Signed-off-by: NKristian Høgsberg <krh@redhat.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This is a mechanical clean-up of the way *.c files include
system header files.

 (1) sources under compat/, platform sha-1 implementations, and
     xdelta code are exempt from the following rules;

 (2) the first #include must be "git-compat-util.h" or one of
     our own header file that includes it first (e.g. config.h,
     builtin.h, pkt-line.h);

 (3) system headers that are included in "git-compat-util.h"
     need not be included in individual C source files.

 (4) "git-compat-util.h" does not have to include subsystem
     specific header files (e.g. expat.h).
Signed-off-by: NJunio C Hamano <junkio@cox.net>

The intent is to lib-ify colorizing code so it can be reused.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <junkio@cox.net>