difftool--helper: exit when reading a prompt answer fails

An attempt to quit difftool by hitting Ctrl-D (EOF) at its prompt does
not quit it, but is treated as if 'yes' was answered to the prompt and
all following prompts, which is contrary to the user's intent. Fix the
error check.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
git-compat-util.h: support variadic macros with the XL C compiler

When the XL C compiler is run with an appropriate language level or
suboption, it defines a feature test macro to indicate support for
variadic macros by defining __C99_MACRO_WITH_VA_ARGS C preprocessor
macro.

This was tested on z/OS, but it should also work on AIX according
to IBM documentation.

Signed-off-by: David Michael <fedora.dm0@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Makefile: reorder linker flags in the git executable rule

The XL C compiler can fail due to mixing library path and object
file arguments, for example when linking git while building with
"gmake LDFLAGS=-L$prefix/lib".

Move the ALL_LDFLAGS variable expansion in the git executable rule
to be consistent with all the other linking rules, namely to have
LDFLAGS such as -L$where before the object files *.o being linked
together.

Signed-off-by: David Michael <fedora.dm0@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
compat/bswap.h: detect endianness from XL C compiler macros

There is no /usr/include/endian.h equivalent on z/OS, but the
compiler will define macros to indicate endianness on host and
target hardware.  This adds a test for these macros as a last
resort for determining byte order.

Signed-off-by: David Michael <fedora.dm0@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Documentation: refactor common operations into variables

The Makefile performs several very similar tasks to convert AsciiDoc
files into either HTML or DocBook.  Move these items into variables to
reduce the duplication.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Documentation: remove Asciidoctor linkgit macro

Asciidoctor provides an extension implementing a backend-independent
macro for dealing with manpage links just like the linkgit macro.  As
this is more likely to be up-to-date with future changes in Asciidoctor,
prefer using it over reimplementing in Git.

This reverts commit 773ee47c2b9c691d9758b2bea6cac10e3f0c4e12.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
t/lib-gpg: make gpghome files writable

t/lib-gpg.sh copies the test environment's gpg home to the trash
directory and makes sure the directoty is writable.

Make sure the copied files are writable, too.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Revert "grep: fix match highlighting for combined patterns with context lines"

This reverts commit d5a7410d22075ecf9f2597d2516bb9914cd55049.

It turns out that showing partial matches on the lines that are not
matching ones is a feature, not a bug, modelling after ms/mc
specifiers in GNU grep's environment variables GREP_COLORS.
strbuf_add_commented_lines(): avoid SP-HT sequence in commented lines

The strbuf_add_commented_lines() function passes a pair of prefixes,
one to be used for a non-empty line, and the other for an empty
line, to underlying add_lines().  The former is set to a comment
char followed by a SP, while the latter is set to just the comment
char.  This is designed to give a SP after the comment character,
e.g. "# <user text>\n", on a line with some text, and to avoid
emitting an unsightly "# \n" for an empty line.

Teach this machinery to also use the latter space-less prefix when
the payload line begins with a tab, to show e.g. "#\t<user text>\n";
otherwise we will end up showing "# \t<user text>\n" which is
similarly unsightly.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
dir.c: optionally compute sha-1 of a .gitignore file

This is not used anywhere yet. But the goal is to compare quickly if a
.gitignore file has changed when we have the SHA-1 of both old (cached
somewhere) and new (from index or a tree) versions.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
untracked cache: record .gitignore information and dir hierarchy

The idea is if we can capture all input and (non-rescursive) output of
read_directory_recursive(), and can verify later that all the input is
the same, then the second r_d_r() should produce the same output as in
the first run.

The requirement for this to work is stat info of a directory MUST
change if an entry is added to or removed from that directory (and
should not change often otherwise). If your OS and filesytem do not
meet this requirement, untracked cache is not for you. Most file
systems on *nix should be fine. On Windows, NTFS is fine while FAT may
be not [1] even though FAT on Linux seems to be fine.

The list of input of r_d_r() is in the big comment block in dir.h. In
short, the output of a directory (not counting subdirs) mainly depends
on stat info of the directory in question, all .gitignore leading to
it and the check_only flag when r_d_r() is called recursively. This
patch records all this info (and the output) as r_d_r() runs.

Two hash_sha1_file() are required for $GIT_DIR/info/exclude and
core.excludesfile unless their stat data matches. hash_sha1_file() is
only needed when .gitignore files in the worktree are modified,
otherwise their SHA-1 in index is used (see the previous patch).

We could store stat data for .gitignore files so we don't have to
rehash them if their content is different from index, but I think
.gitignore files are rarely modified, so not worth extra cache data
(and hashing penalty read-cache.c:verify_hdr(), as we will be storing
this as an index extension).

The implication is, if you change .gitignore, you better add it to the
index soon or you lose all the benefit of untracked cache because a
modified .gitignore invalidates all subdirs recursively. This is
especially bad for .gitignore at root.

This cached output is about untracked files only, not ignored files
because the number of tracked files is usually small, so small cache
overhead, while the number of ignored files could go really high
(e.g. *.o files mixing with source code).

[1] "Description of NTFS date and time stamps for files and folders"
    http://support.microsoft.com/kb/299648

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
untracked cache: initial untracked cache validation

Make sure the starting conditions and all global exclude files are
good to go. If not, either disable untracked cache completely, or wipe
out the cache and start fresh.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
untracked cache: invalidate dirs recursively if .gitignore changes

It's easy to see that if an existing .gitignore changes, its SHA-1
would be different and invalidate_gitignore() is called.

If .gitignore is removed, add_excludes() will treat it like an empty
.gitignore, which again should invalidate the cached directory data.

if .gitignore is added, lookup_untracked() already fills initial
.gitignore SHA-1 as "empty file", so again invalidate_gitignore() is
called.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
untracked cache: make a wrapper around {open,read,close}dir()

This allows us to feed different info to read_directory_recursive()
based on untracked cache in the next patch.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
untracked cache: record/validate dir mtime and reuse cached output

The main readdir loop in read_directory_recursive() is replaced with a
new one that checks if cached results of a directory is still valid.

If a file is added or removed from the index, the containing directory
is invalidated (but not its subdirs). If directory's mtime is changed,
the same happens. If a .gitignore is updated, the containing directory
and all subdirs are invalidated recursively. If dir_struct#flags or
other conditions change, the cache is ignored.

If a directory is invalidated, we opendir/readdir/closedir and run the
exclude machinery on that directory listing as usual. If untracked
cache is also enabled, we'll update the cache along the way. If a
directory is validated, we simply pull the untracked listing out from
the cache. The cache also records the list of direct subdirs that we
have to recurse in. Fully excluded directories are seen as "untracked
files".

In the best case when no dirs are invalidated, read_directory()
becomes a series of

  stat(dir), open(.gitignore), fstat(), read(), close() and optionally
  hash_sha1_file()

For comparison, standard read_directory() is a sequence of

  opendir(), readdir(), open(.gitignore), fstat(), read(), close(), the
  expensive last_exclude_matching() and closedir().

We already try not to open(.gitignore) if we know it does not exist,
so open/fstat/read/close sequence does not apply to every
directory. The sequence could be reduced further, as noted in
prep_exclude() in another patch. So in theory, the entire best-case
read_directory sequence could be reduced to a series of stat() and
nothing else.

This is not a silver bullet approach. When you compile a C file, for
example, the old .o file is removed and a new one with the same name
created, effectively invalidating the containing directory's cache
(but not its subdirectories). If your build process touches every
directory, this cache adds extra overhead for nothing, so it's a good
idea to separate generated files from tracked files.. Editors may use
the same strategy for saving files. And of course you're out of luck
running your repo on an unsupported filesytem and/or operating system.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
untracked cache: mark what dirs should be recursed/saved

If we redo this thing in a functional style, we would have one struct
untracked_dir as input tree and another as output. The input is used
for verification. The output is a brand new tree, reflecting current
worktree.

But that means recreate a lot of dir nodes even if a lot could be
shared between input and output trees in good cases. So we go with the
messy but efficient way, combining both input and output trees into
one. We need a way to know which node in this combined tree belongs to
the output. This is the purpose of this "recurse" flag.

"valid" bit can't be used for this because it's about data of the node
except the subdirs. When we invalidate a directory, we want to keep
cached data of the subdirs intact even though we don't really know
what subdir still exists (yet). Then we check worktree to see what
actual subdir remains on disk. Those will have 'recurse' bit set
again. If cached data for those are still valid, we may be able to
avoid computing exclude files for them. Those subdirs that are deleted
will have 'recurse' remained clear and their 'valid' bits do not
matter.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
untracked cache: don't open non-existent .gitignore

This cuts down a signficant number of open(.gitignore) because most
directories usually don't have .gitignore files.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
untracked cache: save to an index extension

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
untracked cache: load from UNTR index extension

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
untracked cache: invalidate at index addition or removal

Ideally we should implement untracked_cache_remove_from_index() and
untracked_cache_add_to_index() so that they update untracked cache
right away instead of invalidating it and wait for read_directory()
next time to deal with it. But that may need some more work in
unpack-trees.c. So stay simple as the first step.

The new call in add_index_entry_with_check() may look strange because
new calls usually stay close to cache_tree_invalidate_path(). We do it
a bit later than c_t_i_p() in this function because if it's about
replacing the entry with the same name, we don't care (but cache-tree
does).

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>