[libcamera-devel] [PATCH 2/6] libcamera-platform: Introduce new platform library

[Kieran Bingham]

Hi Umang,

On 17/06/2021 06:32, Umang Jain wrote:
> Hi Kieran,
> 
> On 6/16/21 8:41 PM, Kieran Bingham wrote:
>> The libcamera-platform.so will feature internal support functionality
>> that is utilised by libcamera, and can be shared in other places.
> 
> this sounds similar to -dev / -devel packages listed in distributions.
> May we can use that suffix? :-)

I don't think we can I'm afraid.
the -dev packages are used to imply an application can use that package
to build against libcamera.

In this case it's exactly the opposite - this is for /libcamera/ (and
permitted components, like IPAs, proxy-workers, even android-hal) to
share 'private' libcamera interfaces.

But they shouldn't be provided to application developers who would be
the users expecting a libcamera-dev or libcamera-devel package to
utilise libcamera.



> libcamera: A complex camera support library for Linux, Android, and
> ChromeOS
> libcamera-dev: Development files for libcamera
> 
> 
>>
>> However - the libcamera-platform library does not constitute a part
>> of the public libcamera API directly. It is a layer beneath libcamera
>> which provides common abstractions to internal objects.
>>
>> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
>> ---
>>   Documentation/Doxyfile.in              |  4 +++-
>>   Documentation/meson.build              |  2 ++
>>   include/libcamera/meson.build          |  1 +
>>   include/libcamera/platform/meson.build |  9 ++++++++
>>   src/libcamera-platform/meson.build     | 29 ++++++++++++++++++++++++++
>>   src/libcamera/meson.build              |  2 ++
>>   src/meson.build                        |  1 +
>>   7 files changed, 47 insertions(+), 1 deletion(-)
>>   create mode 100644 include/libcamera/platform/meson.build
>>   create mode 100644 src/libcamera-platform/meson.build
>>
>> diff --git a/Documentation/Doxyfile.in b/Documentation/Doxyfile.in
>> index 8305f56af7a8..c1b395bf0b83 100644
>> --- a/Documentation/Doxyfile.in
>> +++ b/Documentation/Doxyfile.in
>> @@ -791,8 +791,10 @@ WARN_LOGFILE           =
>>   INPUT                  = "@TOP_SRCDIR@/include/libcamera" \
>>                "@TOP_SRCDIR@/src/ipa/libipa" \
>>                "@TOP_SRCDIR@/src/libcamera" \
>> +             "@TOP_SRCDIR@/src/libcamera-platform" \
>>                "@TOP_BUILDDIR@/include/libcamera" \
>> -             "@TOP_BUILDDIR@/src/libcamera"
>> +             "@TOP_BUILDDIR@/src/libcamera" \
>> +             "@TOP_BUILDDIR@/src/libcamera-platform"
>>     # This tag can be used to specify the character encoding of the
>> source files
>>   # that doxygen parses. Internally doxygen uses the UTF-8 encoding.
>> Doxygen uses
>> diff --git a/Documentation/meson.build b/Documentation/meson.build
>> index 9ecf4dfcf79f..01b753f07fb6 100644
>> --- a/Documentation/meson.build
>> +++ b/Documentation/meson.build
>> @@ -27,6 +27,8 @@ if doxygen.found() and dot.found()
>>                         libcamera_ipa_interfaces,
>>                         libcamera_public_headers,
>>                         libcamera_sources,
>> +                      libcamera_platform_headers,
>> +                      libcamera_platform_sources,
>>                         libipa_headers,
>>                         libipa_sources,
>>                     ],
>> diff --git a/include/libcamera/meson.build
>> b/include/libcamera/meson.build
>> index 086c958b0a53..2c3bbeb8df36 100644
>> --- a/include/libcamera/meson.build
>> +++ b/include/libcamera/meson.build
>> @@ -25,6 +25,7 @@ include_dir = libcamera_include_dir / 'libcamera'
>>     subdir('internal')
>>   subdir('ipa')
>> +subdir('platform')
>>     install_headers(libcamera_public_headers,
>>                   subdir : include_dir)
>> diff --git a/include/libcamera/platform/meson.build
>> b/include/libcamera/platform/meson.build
>> new file mode 100644
>> index 000000000000..c8e0d0c5ba12
>> --- /dev/null
>> +++ b/include/libcamera/platform/meson.build
>> @@ -0,0 +1,9 @@
>> +# SPDX-License-Identifier: CC0-1.0
>> +
>> +libcamera_platform_include_dir = libcamera_include_dir / 'platform'
>> +
>> +libcamera_platform_headers = files([
>> +])
>> +
>> +install_headers(libcamera_platform_headers,
>> +                subdir: libcamera_platform_include_dir)
>> diff --git a/src/libcamera-platform/meson.build
>> b/src/libcamera-platform/meson.build
>> new file mode 100644
>> index 000000000000..64d0dfee2731
>> --- /dev/null
>> +++ b/src/libcamera-platform/meson.build
>> @@ -0,0 +1,29 @@
>> +# SPDX-License-Identifier: CC0-1.0
>> +
>> +libcamera_platform_sources = files([
>> +])
>> +
>> +libcamera_platform_deps = [
>> +]
>> +
>> +libcamera_platform_lib = shared_library('libcamera_platform',
>> +                                       [libcamera_platform_sources,
>> libcamera_platform_headers],
>> +                                       name_prefix : '',
>> +                                       install : true,
>> +                                       cpp_args : libcamera_cpp_args,
>> +                                       include_directories :
>> libcamera_includes,
> 
> 
> isn't libcamera_includes an overkill here? Since we are splitting off
> the libraries, I think we should map the relevant include-directories
> for that component? I don't expect you to fix this in this series, but
> just wanted to see if this was the right way ahead?


These platform headers share a common base with libcamera.

#include <libcamera/request.h>
#include <libcamera/platform/file.h>

The difference is in who is allowed to use them ...



>> +                                       dependencies :
>> libcamera_platform_deps)
>> +
>> +libcamera_platform = declare_dependency(sources : [
>> +                                           libcamera_platform_headers,
>> +                                       ],
>> +                                       include_directories :
>> libcamera_includes,
>> +                                       link_with :
>> libcamera_platform_lib)
>> +
>> +pkg_mod = import('pkgconfig')
>> +pkg_mod.generate(libraries : libcamera_platform_lib,
>> +                 version : '1.0',
>> +                 name : 'libcamera-platform',
>> +                 filebase : 'camera-platform',
>> +                 description : 'Complex Camera Support Library',
>> +                 subdirs : 'libcamera')
>> diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build
>> index 54512652272c..6ba59e4006cb 100644
>> --- a/src/libcamera/meson.build
>> +++ b/src/libcamera/meson.build
>> @@ -127,6 +127,7 @@ libcamera_deps = [
>>       libgnutls,
>>       liblttng,
>>       libudev,
>> +    libcamera_platform,
>>       dependency('threads'),
>>   ]
>>   @@ -156,6 +157,7 @@ libcamera_dep = declare_dependency(sources : [
>>                                          libcamera_generated_ipa_headers,
>>                                      ],
>>                                      include_directories :
>> libcamera_includes,
>> +                                   dependencies: libcamera_platform,
>>                                      link_with : libcamera)
>>     subdir('proxy/worker')
>> diff --git a/src/meson.build b/src/meson.build
>> index a4e96ecd728a..70e1a4618a0f 100644
>> --- a/src/meson.build
>> +++ b/src/meson.build
>> @@ -29,6 +29,7 @@ libcamera_cpp_args = []
>>   libcamera_objects = []
>>     # libcamera must be built first as a dependency to the other
>> components.
>> +subdir('libcamera-platform')
>>   subdir('libcamera')
>>     subdir('android')

-- 
Regards
--
Kieran