Re: [PATCH 0/1 v3] libv4l: Add plugin support

[Yordan Kamenov <ykamenov@mm-sol.com>]

Hi Hans,

any comments on that?

Regards
Yordan



Yordan Kamenov wrote:
> Hi Hans,
>
> here is third version of plugin support for libv4l2.
>
> Changes in v3:
>
> * Pass opened fd to the plugin instead of filename
> * Plugin private data is returned by init call and is passed as argument
>   in ioctl/read/close (remove libv4l2_set/get_plugindata functions)
> * Plugin do not handle mmap/munmap
>
>
>
> --------------------------------------------------------------------------
> Changes in v2:
>
> * Remove calls of v4l2_plugin_foo functions in the beginning of coresponding
>   v4l2_foo functions and instead replace SYS_FOO calls.
> * Add to v4l2_dev_info device operation structure which can hold plugin
>   callbacks or dyrect syscall(SYS_foo, ...) calls.
> * Under libv4lconvert also replace SYS_FOO cals with device operations. This
>   required also to add dev_ops field to v4lconvert_data and v4lcontrol_data.
>
> ---------------------------------------------------------------------------
> v1:
>
> Here is initial version of plugin support for libv4l, based on your RFC.
>
> It is provided by functions v4l2_plugin_[open,close,etc]. When open() is
> called libv4l dlopens files in /usr/lib/libv4l/plugins 1 at a time and call
> open() callback passing through the applications parameters unmodified.
> If a plugin is relevant for the specified device node, it can indicate so by
> returning a value other then -1 (the actual file descriptor).
>
> As soon as a plugin returns another value then -1 plugin loading stops and
> information about it (fd and corresponding library handle) is stored.
> For each function v4l2_[ioctl,read,close,etc] is called corresponding
> v4l2_plugin_* function which looks if there is loaded plugin for that file
> and call it's callbacks. v4l2_plugin_* functions indicate by their first
> argument if plugin was used, and if it was not then v4l2_* functions proceed
> with their usual behavior.
>
>
> Yordan Kamenov (1):
>   libv4l: Add plugin support to libv4l
>
>  lib/include/libv4l2-plugin.h                   |   36 ++++++
>  lib/include/libv4lconvert.h                    |    5 +-
>  lib/libv4l2/Makefile                           |    4 +-
>  lib/libv4l2/libv4l2-priv.h                     |   10 ++
>  lib/libv4l2/libv4l2.c                          |   90 ++++++++++----
>  lib/libv4l2/v4l2-plugin.c                      |  160 ++++++++++++++++++++++++
>  lib/libv4l2/v4l2convert.c                      |    9 --
>  lib/libv4lconvert/control/libv4lcontrol-priv.h |    4 +
>  lib/libv4lconvert/control/libv4lcontrol.c      |   35 ++++--
>  lib/libv4lconvert/control/libv4lcontrol.h      |    5 +-
>  lib/libv4lconvert/libv4lconvert-priv.h         |    2 +
>  lib/libv4lconvert/libv4lconvert.c              |   34 ++++--
>  12 files changed, 333 insertions(+), 61 deletions(-)
>  create mode 100644 lib/include/libv4l2-plugin.h
>  create mode 100644 lib/libv4l2/v4l2-plugin.c
>
>