Format-patch generates emails with the "From" address set to the
author of each patch. If you are going to send the emails, however,
you would want to replace the author identity with yours (if they
are not the same), and bump the author identity to an in-body
header.

Normally this is handled by git-send-email, which does the
transformation before sending out the emails. However, some
workflows may not use send-email (e.g., imap-send, or a custom
script which feeds the mbox to a non-git MUA). They could each
implement this feature themselves, but getting it right is
non-trivial (one must canonicalize the identities by reversing any
RFC2047 encoding or RFC822 quoting of the headers, which has caused
many bugs in send-email over the years).

This patch takes a different approach: it teaches format-patch a
"--from" option which handles the ident check and in-body header
while it is writing out the email.  It's much simpler to do at this
level (because we haven't done any quoting yet), and any workflow
based on format-patch can easily turn it on.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

In the current code, callers are expected to fill in the
pretty_print_context, and then the pretty.c functions simply
read from it. This leaves no room for the pretty.c functions
to communicate with each other by manipulating the context
(e.g., data seen while printing the header may impact how we
print the body).

Rather than introduce a new struct to hold modifiable data,
let's just drop the const-ness of the existing context
struct.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

* rs/pp-user-info-without-extra-allocation:
  pretty: remove intermediate strbufs from pp_user_info()
  pretty: simplify output line length calculation in pp_user_info()
  pretty: simplify input line length calculation in pp_user_info()

Use namebuf/namelen and mailbuf/maillen directly instead of copying
their contents into strbufs first.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Keep namelen unchanged and don't use it to hold a value that we're not
interested in anyway -- we can use maillen and the constant part
directly instead.  This simplifies the code slightly and prepares for
the next patch that makes use of the original value of namelen.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Instead of searching for LF and NUL with two strchr() calls use a single
strchrnul() call.  We don't need to check if the returned pointer is NULL
because either we'll find the NUL at the end of line, or the caller
forgot to NUL-terminate the string and we'll overrun the buffer in any
case.  Also we don't need to pass LF or NUL to split_ident_line() as it
ignores it anyway.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

pretty-printing body of the commit that is stored in non UTF-8
encoding did not work well.  The early part of this series fixes
it.  And then it adds %C(auto) specifier that turns the coloring on
when we are emitting to the terminal, and adds column-aligning
format directives.

* nd/pretty-formats:
  pretty: support %>> that steal trailing spaces
  pretty: support truncating in %>, %< and %><
  pretty: support padding placeholders, %< %> and %><
  pretty: add %C(auto) for auto-coloring
  pretty: split color parsing into a separate function
  pretty: two phase conversion for non utf-8 commits
  utf8.c: add reencode_string_len() that can handle NULs in string
  utf8.c: add utf8_strnwidth() with the ability to skip ansi sequences
  utf8.c: move display_mode_esc_sequence_len() for use by other functions
  pretty: share code between format_decoration and show_decorations
  pretty-formats.txt: wrap long lines
  pretty: get the correct encoding for --pretty:format=%e
  pretty: save commit encoding from logmsg_reencode if the caller needs it

A commit object whose author or committer ident are malformed
crashed some code that trusted that a name, an email and an
timestamp can always be found in it.

* jk/chopped-ident:
  blame: handle broken commit headers gracefully
  pretty: handle broken commit headers gracefully
  cat-file: print tags raw for "cat-file -p"

This is pretty useful in `%<(100)%s%Cred%>(20)% an' where %s does not
use up all 100 columns and %an needs more than 20 columns. By
replacing %>(20) with %>>(20), %an can steal spaces from %s.

%>> understands escape sequences, so %Cred does not stop it from
stealing spaces in %<(100).

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

%>(N,trunc) truncates the right part after N columns and replace the
last two letters with "..". ltrunc does the same on the left. mtrunc
cuts the middle out.

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