C/C++ coding style
==================

Tools
-----

There is a file uncrustify.cfg in this directory that can be used to
approximate the prevailing code style. You can run it with e.g.

   uncrustify --replace -c devel/uncrustify.cfg foo.c

You still have to use your judgement about accepting or rejecting the
changes uncrustify makes. With a nice git frontend, you can add the
lines you agree with and reject the rest.

For Emacs users, the file .dir-locals.el in the top level source
directory will configure c-mode to automatically meet most of the
basic layout rules.  I

Indentation, Whitespace, and Layout
-----------------------------------

The following nonsense code demonstrates many aspects of the style:

static some_type
function (param_type param, param_type param)
{
   for (int i = 0; i < 10; i++) {
       int j;

       j = i + 10;

       some_other_func (j, i);
   }
}

* Indent is 4 spaces with mixed tab/spaces and a tab width of 8.
  (Specifically, a line should begin with zero or more tabs followed
  by fewer than eight spaces.)

* Use copious whitespace.  In particular
   - there is a space between the function name and the open paren in a call.
   - likewise, there is a space following keywords such as if and while
   - every binary operator should have space on either side.

* No trailing whitespace. Please enable the standard pre-commit hook in git
  (or an equivalent hook). The standard pre-commit hook is enabled by simply
  renaming file '.git/hooks/pre-commit.sample' to '.git/hooks/pre-commit' .

* The name in a function prototype should start at the beginning of a line.

* Opening braces "cuddle" (they are on the same line as the
  if/for/while test) and are preceded by a space. The opening brace of
  functions is the exception, and starts on a new line.

* Opening parens also cuddle, even if the first argument does not fit
  on the same line.

* Ternary operators that span a line should be parenthesized like as
  "a ? (\n b ) : c". This is mainly to keep the indentation tools
  happy.

* Comments are always C-style /* */ block comments, with a leading *
  each line.  They should start with a capital letter and generally be
  written in complete sentences.  Public library functions are
  documented immediately before their prototype in lib/notmuch.h.
  Internal functions are typically documented immediately before their
  definition.

* Code lines should be less than 80 columns and comments should be
  wrapped at 70 columns.

* Variable declarations should be at the top of a block; C99 style
  control variable declarations in for loops are also OK.

Naming
------

* Use lowercase_with_underscores for function, variable, and type
  names.

* Except for variables with extremely small scope, and perhaps loop
  indices, when naming variables and functions, err on the side of
  verbosity.

* All structs should be typedef'd to a name ending with _t.  If the
  struct has a tag, it should be the same as the typedef name, minus
  the trailing _t.

CLI conventions
---------------

* Any changes to the JSON output format of search or show need an
  accompanying change to devel/schemata.

libnotmuch conventions
----------------------------------

* Functions starting with notmuch_ in lib/notmuch.h are public and are
  automatically exported from the shared library.  Private library
  functions should generally either be static or, if they are shared
  between compilation units, start with _notmuch.

* Functions in libnotmuch must not access user configuration files
  (i.e. .notmuch-config)

* Code which needs to be accessed from both the CLI and from
  libnotmuch should be factored out into libutil (under util/).

* Deprecated functions should be marked with the NOTMUCH_DEPRECATED
  macro which generates run time warnings with gcc and clang. In order
  not to confuse doxygen this should go at the beginning of the
  declaration like:

  NOTMUCH_DEPRECATED(major,minor) notmuch_status_t notmuch_dwim(void *arg);

  The @deprecated doxygen command can be used to generate markup in
  the API docs.
