[libcamera-devel] [PATCH 16/16] test: Ensure LIBCAMERA_BASE_PRIVATE isn't public

[Kieran Bingham]

Hi Paul,

On 25/06/2021 10:05, paul.elder at ideasonboard.com wrote:
> Hi Kieran,
> 
> On Fri, Jun 25, 2021 at 02:35:39AM +0100, Kieran Bingham wrote:
>> If LIBCAMERA_BASE_PRIVATE is ever exposed on the libcamera public dependencies,
>> then the private.h header protection will be circumvented.
>>
>> Provide a test which will fail (at compile time) if the LIBCAMERA_BASE_PRIVATE
>> define ever leaks to the public dependencies.
>>
>> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
>> ---
>>  test/meson.build    |  1 +
>>  test/public-api.cpp | 25 +++++++++++++++++++++++++
>>  2 files changed, 26 insertions(+)
>>  create mode 100644 test/public-api.cpp
>>
>> diff --git a/test/meson.build b/test/meson.build
>> index 73eb44d03ad0..2c3e76546fbc 100644
>> --- a/test/meson.build
>> +++ b/test/meson.build
>> @@ -25,6 +25,7 @@ subdir('v4l2_videodevice')
>>  
>>  public_tests = [
>>      ['geometry',                        'geometry.cpp'],
>> +    ['public-api',                      'public-api.cpp'],
>>      ['signal',                          'signal.cpp'],
>>      ['span',                            'span.cpp'],
>>  ]
>> diff --git a/test/public-api.cpp b/test/public-api.cpp
>> new file mode 100644
>> index 000000000000..5afce97c6887
>> --- /dev/null
>> +++ b/test/public-api.cpp
>> @@ -0,0 +1,25 @@
>> +/* SPDX-License-Identifier: GPL-2.0-or-later */
>> +/*
>> + * Copyright (C) 2021, Google Inc.
>> + *
>> + * public-api.cpp - Public API validation
>> + */
>> +
>> +#include <libcamera/libcamera.h>
>> +
>> +#include "test.h"
>> +
>> +class PublicAPITest : public Test
>> +{
>> +	int run()
>> +	{
>> +#ifdef LIBCAMERA_BASE_PRIVATE
>> +#error "Public Interfaces should not be exposed to LIBCAMERA_BASE_PRIVATE"
> 
> s/be exposed to/expose/ ?

Hrm, that's not actually my intention. It would check both cases though.
It's subtle, ...

My intention is to prevent someone adding or changing the meson
dependencies such that somehow libcamera_base_private ends up being a
part of libcamera_public dependency which would then magically make all
public interfaces compile with LIBCAMERA_BASE_PRIVATE defined, and that
would then break all the protection.

But your change, would also be correct and something to protect against
(and which this does protect against) but it's not something I would
expect to happen, as that would imply someone has added a #define
LIBCAMERA_BASE_PRIVATE within one of the API headers (which would then
have the same break.


> Reviewed-by: Paul Elder <paul.elder at ideasonboard.com>
> 
>> +		return TestFail;
>> +#else
>> +		return TestPass;
>> +#endif
>> +	}
>> +};
>> +
>> +TEST_REGISTER(PublicAPITest)
>> -- 
>> 2.30.2
>>