[libgpiod][RFC 0/6] first draft of libgpiod v2.0 API

[Bartosz Golaszewski <brgl@bgdev.pl>]

This series introduces an entirely reworked API for the core C part of
libgpiod. It's not fully functional as the bindings are not modified,
and starting from patch 5, even the tests stop working. This is on
purpose as I'd like to reach an agreement on the interface before
spending time on reworking the tests.

My plan for the development of v2.0 is to keep the changes in a separate
branch until all bits & pieces are complete and then rearrange them into
a bisectable series that will be merged into the master branch.

A couple points regarding the design of the new API:
- all objects have become opaque and can only be accessed using dedicated
  functions
- line objects as well as bulk containers have been removed
- line requests are now configured using three types of structures: attributes,
  line config and request config structures, which follows the kernel API
- line request handles have now a lifetime separate from the parent chips to
  leverage the separation of chip and request file descriptors
- line events are now opaque but they can be stored in a dedicated container
  so that memory allocations are not necessary everytime an event is read from
  the kernel
- the library code has been split into several compilation units for easier
  maintenance

The new API is completely documented in include/gpiod.h doxygen comments.

Please let me know what you think. I am aware that these patches are huge and
difficult to review but I'm really only expecting a general API review - all
other implementation details can be improved later.

The branch from which this series was generated can be found on my github:
  https://github.com/brgl/libgpiod-private/tree/topic/core-lib-API-v2

Bartosz Golaszewski (6):
  treewide: rename chip property accessors
  core: add refcounting helpers
  core: implement line_info objects
  core: rework line events
  core: rework line requests
  core: implement line watch events

 bindings/cxx/chip.cpp         |    6 +-
 bindings/python/gpiodmodule.c |   14 +-
 include/gpiod.h               | 1224 +++++++++++++++++---------------
 lib/Makefile.am               |   15 +-
 lib/attr.c                    |  232 ++++++
 lib/chip.c                    |  234 +++++++
 lib/config.c                  |  158 +++++
 lib/core.c                    | 1240 ---------------------------------
 lib/event.c                   |  218 ++++++
 lib/handle.c                  |  126 ++++
 lib/helpers.c                 |  302 --------
 lib/info.c                    |  171 +++++
 lib/internal.c                |  147 ++++
 lib/internal.h                |   43 ++
 lib/mask.c                    |   43 ++
 lib/misc.c                    |   80 +++
 lib/request.c                 |  118 ++++
 lib/watch.c                   |   96 +++
 tests/gpiod-test.h            |    5 +
 tests/tests-chip.c            |   33 +-
 tests/tests-event.c           |  470 +++++++++----
 tests/tests-line.c            |  425 ++++++++---
 tools/gpio-tools-test.bats    |   12 +-
 tools/gpiodetect.c            |   17 +-
 tools/gpiofind.c              |    3 +-
 tools/gpioget.c               |   57 +-
 tools/gpioinfo.c              |   58 +-
 tools/gpiomon.c               |  130 ++--
 tools/gpioset.c               |   85 ++-
 tools/tools-common.c          |    8 +-
 tools/tools-common.h          |    2 +-
 31 files changed, 3255 insertions(+), 2517 deletions(-)
 create mode 100644 lib/attr.c
 create mode 100644 lib/chip.c
 create mode 100644 lib/config.c
 delete mode 100644 lib/core.c
 create mode 100644 lib/event.c
 create mode 100644 lib/handle.c
 delete mode 100644 lib/helpers.c
 create mode 100644 lib/info.c
 create mode 100644 lib/internal.c
 create mode 100644 lib/mask.c
 create mode 100644 lib/request.c
 create mode 100644 lib/watch.c

-- 
2.30.1