Introduce a new option 'emitted_symbols' in the struct diff_options which
controls whether all output is buffered up until all output is available.
It is set internally in diff.c when necessary.

We'll have a new struct 'emitted_string' in diff.c which will be used to
buffer each line.  The emitted_string will duplicate the memory of the
line to buffer as that is easiest to reason about for now. In a future
patch we may want to decrease the memory usage by not duplicating all
output for buffering but rather we may want to store offsets into the
file or in case of hunk descriptions such as the similarity score, we
could just store the relevant number and reproduce the text later on.

This approach was chosen as a first step because it is quite simple
compared to the alternative with less memory footprint.

emit_diff_symbol factors out the emission part and depending on the
diff_options->emitted_symbols the emission will be performed directly
when calling emit_diff_symbol or after the whole process is done, i.e.
by buffering we have add the possibility for a second pass over the
whole output before doing the actual output.

In 6440d341 (2012-03-14, diff: tweak a _copy_ of diff_options with
word-diff) we introduced a duplicate diff options struct for word
emissions as we may have different regex settings in there.
When buffering the output, we need to operate on just one buffer,
so we have to copy back the emissions of the word buffer into the
main buffer.

Unconditionally enable output via buffer in this patch as it yields
a great opportunity for testing, i.e. all the diff tests from the
test suite pass without having reordering issues (i.e. only parts
of the output got buffered, and we forgot to buffer other parts).
The test suite passes, which gives confidence that we converted all
functions to use emit_string for output.
Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The word diffing is not line oriented and would need some serious
effort to be transformed into a line oriented approach, so
just go with a symbol DIFF_SYMBOL_WORD_DIFF that is a partial line.
Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

We call print_stat_summary from builtin/apply, so we still
need the version with a file pointer, so introduce
print_stat_summary_0 that uses emit_string machinery and
keep print_stat_summary with the same arguments around.
Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

As the submodule process is no longer attached to the same file pointer
'o->file' as the superprojects process, there is a different result in
color.c::check_auto_color. That is why we need to pass coloring explicitly,
such that the submodule coloring decision will be made by the child process
processing the submodule. Only DIFF_SYMBOL_SUBMODULE_PIPETHROUGH contains
color, the other symbols are for embedding the submodule output into the
superprojects output.

Remove the colors from the function signatures, as all the coloring
decisions will be made either inside the child process or the final
emit_diff_symbol, but not in the functions driving the submodule diff.
Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

we could save a little bit of memory when buffering in a later mode
by just passing the inner part ("%s and %s", file1, file 2), but
those a just a few bytes, so instead let's reuse the implementation from
DIFF_SYMBOL_HEADER and keep the whole line around.
Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The header is constructed lazily including line breaks, so just emit
the raw string as is.
Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

We have to use fprintf instead of emit_line, because we want to emit the
tab after the color. This is important for ancient versions of gnu patch
AFAICT, although we probably do not want to feed colored output to the
patch utility, such that it would not matter if the trailing tab is
colored. Keep the corner case as-is though.
Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The context marker use the exact same output pattern, so reuse it.
Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Add a new flags field to emit_diff_symbol, that will be used by
context lines for:
* white space rules that are applicable (The first 12 bits)
  Take a note in cahe.c as well, when this ws rules are extended we have
  to fix the bits in the flags field.
* how the rules are evaluated (actually this double encodes the sign
  of the line, but the code is easier to keep this way, bits 13,14,15)
* if the line a blank line at EOF (bit 16)

The check if new lines need to be marked up as extra lines at the end of
file, is now done unconditionally. That should be ok, as
'new_blank_line_at_eof' has a quick early return.
Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

In a later patch we want to buffer all output before emitting it as a
new feature ("markup moved lines") conceptually cannot be implemented
in a single pass over the output.

There are different approaches to buffer all output such as:
* Buffering on the char level, i.e. we'd have a char[] which would
  grow at approximately 80 characters a line. This would keep the
  output completely unstructured, but might be very easy to implement,
  such as redirecting all output to a temporary file and working off
  that. The later passes over the buffer are quite complicated though,
  because we have to parse back any output and then decide if it should
  be modified.

* Buffer on a line level. As the output is mostly line oriented already,
  this would make sense, but it still is a bit awkward as we'd have to
  make sense of it again by looking at the first characters of a line
  to decide what part of a diff a line is.

* Buffer semantically. Imagine there is a formal grammar for the diff
  output and we'd keep the symbols of this grammar around. This keeps
  the highest level of structure in the buffered data, such that the
  actual memory requirements are less than say the first option. Instead
  of buffering the characters of the line, we'll buffer what we intend
  to do plus additional information for the specifics. An output of

    diff --git a/new.txt b/new.txt
    index fa69b07..412428c 100644
    Binary files a/new.txt and b/new.txt differ

  could be buffered as
     DIFF_SYMBOL_DIFF_START + new.txt
     DIFF_SYMBOL_INDEX_MODE + fa69b07 412428c "non-executable" flag
     DIFF_SYMBOL_BINARY_FILES + new.txt

This and the following patches introduce the third option of buffering
by first moving any output to emit_diff_symbol, and then introducing the
buffering in this function.
Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

In a later patch we want to do more things before and after all filepairs
are flushed. So factor flushing out all file pairs into its own function
that the new code can be plugged in easily.
Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The emit_hunk_header() function is responsible for assembling a
hunk header and calling emit_line() to send the hunk header
to the output file.  Its only caller fn_out_consume() needs
to prepare for a case where the function emits an incomplete
line and add the terminating LF.

Instead make sure emit_hunk_header() to always send a
completed line to emit_line().
Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

We already have dereferenced 'p->two' into a local variable 'two'.
Use that.
Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

* sb/hashmap-customize-comparison: (566 commits)
  hashmap: migrate documentation from Documentation/technical into header
  patch-ids.c: use hashmap correctly
  hashmap.h: compare function has access to a data field
  Twelfth batch for 2.14
  Git 2.13.2
  Eleventh batch for 2.14
  Revert "split-index: add and use unshare_split_index()"
  Tenth batch for 2.14
  add--interactive: quote commentChar regex
  add--interactive: handle EOF in prompt_yesno
  auto-correct: tweak phrasing
  docs: update 64-bit core.packedGitLimit default
  t7508: fix a broken indentation
  grep: fix erroneously copy/pasted variable in check/assert pattern
  Ninth batch for 2.14
  glossary: define 'stash entry'
  status: add optional stash count information
  stash: update documentation to use 'stash entry'
  for_each_bisect_ref(): don't trim refnames
  mergetools/meld: improve compatibiilty with Meld on macOS X
  ...

While at it, clarify the use of `key`, `keydata`, `entry_or_key` as well
as documenting the new data pointer for the compare function.

Rework the example.
Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

As alluded to in the previous patch, the code in patch-ids.c is
using the hashmaps API wrong.

Luckily we do not have a bug, as all hashmap functionality that we use
here (hashmap_get) passes through the keydata.  If hashmap_get_next were
to be used, a bug would occur as that passes NULL for the key_data.

So instead use the hashmap API correctly and provide the caller required
data in the compare function via the first argument that always gets
passed and was setup via the hashmap_init function.
Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When using the hashmap a common need is to have access to caller provided
data in the compare function. A couple of times we abuse the keydata field
to pass in the data needed. This happens for example in patch-ids.c.

This patch changes the function signature of the compare function
to have one more void pointer available. The pointer given for each
invocation of the compare function must be defined in the init function
of the hashmap and is just passed through.

Documentation of this new feature is deferred to a later patch.
This is a rather mechanical conversion, just adding the new pass-through
parameter.  However while at it improve the naming of the fields of all
compare functions used by hashmaps by ensuring unused parameters are
prefixed with 'unused_' and naming the parameters what they are (instead
of 'unused' make it 'unused_keydata').
Signed-off-by: NStefan Beller <sbeller@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

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

Message update.

* mb/reword-autocomplete-message:
  auto-correct: tweak phrasing

Cosmetic update to a test.

* ks/t7508-indent-fix:
  t7508: fix a broken indentation

"git add -p" were updated in 2.12 timeframe to cope with custom
core.commentchar but the implementation was buggy and a
metacharacter like $ and * did not work.

* jk/add-p-commentchar-fix:
  add--interactive: quote commentChar regex
  add--interactive: handle EOF in prompt_yesno

Doc update for a topic already in 'master'.

* dt/raise-core-packed-git-limit:
  docs: update 64-bit core.packedGitLimit default

Bugfix for a topic that is (only) in 'master'.

* mh/packed-ref-store-prep:
  for_each_bisect_ref(): don't trim refnames
  lock_packed_refs(): fix cache validity check

"git status" learned to optionally give how many stash entries the
user has in its output.

* lb/status-stash-count:
  glossary: define 'stash entry'
  status: add optional stash count information
  stash: update documentation to use 'stash entry'

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

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

Doc update.

* sn/reset-doc-typofix:
  doc: git-reset: fix a trivial typo

Doc update.

* sg/doc-pretty-formats:
  docs/pretty-formats: stress that %- removes all preceding line-feeds

New test.

* sd/t3200-branch-m-test:
  t3200: add test for single parameter passed to -m option

Code clean-up.

* sg/revision-parser-skip-prefix:
  revision.c: use skip_prefix() in handle_revision_pseudo_opt()
  revision.c: use skip_prefix() in handle_revision_opt()
  revision.c: stricter parsing of '--early-output'
  revision.c: stricter parsing of '--no-{min,max}-parents'
  revision.h: turn rev_info.early_output back into an unsigned int

New tests.

* km/test-mailinfo-b-failure:
  t5100: add some more mailinfo tests

Doc update to a recently graduated topic.

* sb/submodule-rm-absorb:
  Documentation/git-rm: correct submodule description