The ControlEnum and Control helper classes defined in gen-controls.py
are useful for other generator scripts. Move them to a separate file to
make it possible to share them.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Jinja2 templates help separate the logic related to the template from
the generation of the data. The python code becomes much clearer as a
result.
As an added bonus, we can use a single template file for both controls
and properties.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Python scripts run as part of the build process need to take a few
actions specific to the environment in which they operate. One of those
is disabling the Python bytecode cache, to avoid writing .pyc files to
the source tree. This is done manually in the IPC generate.py and
parser.py scripts.
The current implementation is not ideal because it hardcodes in the
scripts information related to the environment in which they operate. As
those scripts are part of libcamera this is more of a theoretical issue
than a practical one. A second issue is that future Python scripts will
need to duplicate similar mechanisms, resulting in a higher maintenance
burden.
Address the issue with a different approach, by creating a meson
environment for the Python scripts, and passing it to the
custom_target() functions. The environment only disables the bytecode
cache for now.
The diffstat shows an increase in code size. This is expected to be
offset by usage of the environment for more Python scripts, as well as
support of more variables in the environment.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Commit 829acb3ab0 ("libcamera: Drop file name from header comment
blocks in templates") dropped file names from header comment blocks in
templates, but forgot the control and property .cpp templates. Fix it.
Fixes: 829acb3ab0 ("libcamera: Drop file name from header comment blocks in templates")
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
The header for controls and properties are generated from the
control_ids.h.in and property_ids.h.in templates respectively, and the
generated files are named control_ids.h and property_ids.h.
For sources, the templates are named control_ids.cpp.in and
property_ids.cpp.in, but the output files are named controls_ids.cpp and
properties_ids.cpp. This discrepancy causes confusion. Fix it.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
When generating control headers, the YAML files to be used are
determined dynamically based on the selected pipeline handlers. As part
of this process, the build system populates an array of meson File
objects used as an input for the control headers generation custom
target, as well as an array of file names (as strings). The file names
array is later used to generate the control source files for the
libcamera core, as well as the source code for controls support in the
Python bindings.
Both of the source code generators manually turn the array of file names
into File objects. This duplicates code and reduces readability. A third
similar implementation has also been proposed to generate control
support sources in the GStreamer element, making the issue worse.
To simplify this, store File objects instead of file names in the
controls_files array. As the meson configuration summary doesn't support
File objects, create a separate controls_files_names to store the file
names for that sole purpose.
The exact same process occurs for properties, address them the same way.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
The API reference pages generated by Doxygen are comprehensive, but
therefore quite overwhelming for application developers who will
likely never need to use the majority of the library's objects. To
reduce the complexity of the documentation, split it into two runs of
doxygen.
The first run of doxygen is for the public API. We pass a specific list
of source files to parse, which is built from the arrays of public
headers and sources in meson build files. This ensures that we only
generate the documentation for code from those files.
A custom Python script is needed to add the list of input files to
Doxyfile, as several of the objects included in the header and source
array are custom_tgt objects, which can't be handled as strings to
populate a variable in the configuration data.
The headers defining the Extensible and Object classes (class.h and
object.h respectively), as well as the corresponding source files, are
excluded from the public API documentation despite being referenced in
the meson public headers and sources arrays. This is due to the fact
that public API classes inherit from Extensible and Object, making the
Extensible and Object classes part of the public ABI. Those two base
classes are however implementation details and must not be accessed
directly by application code.
The second run of doxygen is for the internal API. This contains
documentation for all of the library's objects as it currently does.
This set will now be output into build/Documentation/internal-api-html.
Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
Co-developed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Move the section of the Thread support page dealing with thread safety
to a dedicated .dox file at Documentation/. This is done to support the
splitting of the Documentation into a public and internal version. With
a separate page, references can be made to thread safety without having
to include the Thread class in the doxygen run. Some sections of the new
page are still specific to internal implementations and so are hidden
with the \internal flag and an internal section which is conditionally
included. For now, hardcode it to be included in the Doxyfile.
Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
The udev_monitor_receive_device() can return NULL on an error as
detailed in the man pages for the function.
The udevNotify() handler in the DeviceEnumeratorUdev directly uses the
return value of udev_monitor_receive_device() in successive calls to
process the event without having first checked the udev_device.
Ensure we identify, and handle events where the udev_device can not be
returned successfully.
Bug: https://bugs.libcamera.org/show_bug.cgi?id=230
Reviewed-by: Stefan Klug <stefan.klug@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
The IPAManager class implements a singleton pattern due to the need of
accessing the instance in a static member function. The function now
takes a pointer to a PipelineHandler, which we can use to access the
CameraManager, and from there, the IPAManager.
Add accessors to the internal API to expose the CameraManager from the
PipelineHandler, and the IPAManager from the CameraManager. This
requires allocating the IPAManager dynamically to avoid a loop in
includes. Use those accessors to replace the IPAManager singleton.
Update the IPA interface unit test to instantiate a CameraManager
instead of an IPAManager and ProcessManager, to reflect the new way that
the IPAManager is accessed.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Now that libcamera_internal_sources is separate from
libcamera_internal_headers, perform the same split for
libcamera_public_sources and libcamera_public_headers to ensure
consistency of the build system variables.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
The libcamera_tracepoint_header variable stores the tracepoints.h header
custom target, for the sole purpose of being listed as a source of the
libcamera shared library, through the libcamera_internal_sources
variable.
Add the tracepoints.h header to libcamera_internal_headers instead of
libcamera_internal_sources, and list libcamera_internal_headers as a
source of the shared library, alongside libcamera_internal_sources. This
makes libcamera_internal_sources contain sources only, improving clarity
of the build system variables.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
The IPA headers are listed in two different meson variables, one for
generated headers, and one for the other headers. There's no real reason
for this split, consolidate all of them in the libcamera_ipa_headers
variable.
While at it, don't add the IPA headers to the libcamera_internal_sources
variable, but list libcamera_ipa_headers in the sources for the shared
library. This moves the libcamera_internal_sources variable towards
holding source files, not header files, to improve clarity of the build
system.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
The IPA headers are listed in the libcamera_public and libcamera_private
dependency objects, with the generated headers part of the private
dependency object and the non-generated headers part of the public
dependency object. As neither set of IPA headers are part of the public
API, list them both in the libcamera_private dependency object.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
The libcamera_generated_ipa_headers variable, containing the list of
generated IPA headers, is listed in the sources of IPA modules, as well
as IPA tests. This was done to ensure that the modules and tests get
rebuilt when the generate IPA headers change. However, the dependency is
already handled through the libcamera_private dependency object,
specified for all those modules and tests. There's no need to list the
IPA generated headers as sources. Drop them.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
The *::Private classes are part of the internal API, as their name
implies. They are defined in internal headers, but implemented in the
same source file as their public counterparts. This will cause Doxygen
to complain about missing class definition when splitting the public and
internal API documents, as the internal headers won't be parsed by
Doxygen for the public API documentation.
Marking the classes with \internal isn't enough. The directive prevents
the documentation block from being included in the output, but this
occurs at the generation stage, after the documentation blocks are
parsed. Fix this by completely hidding the implementation of the
*::Private classes from Doxygen using preprocessor conditional
compilation. To do so, introduce a new macro, __DOXYGEN_PUBLIC__, that
will be defined for the public API documentation only.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
The libcamera public API exposes classes that have parts considered
internal. They inherit the Extensible class, and their internal parts
are split into a Private class. Those classes are defined in public API
headers, and their Private counterparts are defined in internal headers
sharing a common file name (in a different directory). Both headers are
documented in the same source file.
For instance, include/libcamera/camera.h contains the public API of the
Camera class, and include/libcamera/internal/camera.h its internal
counterpart. Both are documented in src/libcamera/camera.cpp.
As the internal headers are not part of the public API, they need to be
hidden from the future public API builds. To prepare for doing so, mark
them with the \internal Doxygen directive. Hardcode the Doxygen
INTERNAL_DOCS option to YES to include the internal API. This will be
changed later for the public API documentation build.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
libcamera has two formats.h headers, an internal one in
include/libcamera/internal/, and a public one generated at build time.
The convention is to prefix the internal header name with
libcamera/internal/ in the Doxygen file directive, but formats.cpp only
uses internal/ as a prefix. Unify it with the rest of the code base.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
The Doxygen directive only requires qualifying header file names with a
path to differentiate between multiple header files with the same name.
Most file directives that refer to unambiguous files do not have a
libcamera/ and/or internal/ path prefix, but a few do, most likely due
to copy&paste. Drop the prefix in those few files for consistency.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
libcamera is implemented in C++, use std::vector<> to manage the
dynamically allocated line buffers instead of malloc() and free(). This
simplifies the code and improves memory safety by ensuring no allocation
will be leaked.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Milan Zamazal <mzamazal@redhat.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
When the configuration file for an IPA module is missing, it is reported
as an error in the log, for example:
ERROR IPAProxy ipa_proxy.cpp:149 Configuration file 'imx219.yaml' not found for IPA module 'simple'
This is misleading because several pipelines use uncalibrated.yaml in
such a case and can continue working. And in case of software ISP,
there is currently no other configuration file so the error is always
reported.
On the other hand, in some other cases the presence of the configuration
file is required and it is an error if it is missing.
Let's introduce a new optional argument to IPAProxy::configurationFile
that specifies a fallback file if the requested file is not found. If
the primary requested file is not found and a non-empty fallback file is
specified then a warning is logged and the fallback file is looked up.
If neither the fallback file can be found then only then an error is
logged and the method returns an empty string. This change has also the
benefit of putting the common fallback file ("uncalibrated.yaml")
pattern to a single place.
Signed-off-by: Milan Zamazal <mzamazal@redhat.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
SimplePipelineHandler::match may be called several times for different
pipeline configurations. Not all of these calls must succeed. For
example, for TI AM69 board with a single camera attached, the following
error is reported in the log even when libcamera works fine:
ERROR SimplePipeline simple.cpp:1558 No sensor found
This is because a sensor is found for /dev/media0 but not for
/dev/media1. The error is harmless in such a case and only confuses
users who may think no camera is detected at all. Let's change the
error to info and add the device node to the message to indicate the
error is specific to the given media only. It's up to the callers to
report a fatal error condition if libcamera cannot work due to no
matching pipeline configuration.
Signed-off-by: Milan Zamazal <mzamazal@redhat.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
uClibc doesn't provide memfd_create(), which led libcamera to open-code
the call using syscall(). Sprinkling the code with #ifdef's isn't the
most readable option, so improve it by providing a local implementation
of memfd_create(), and call the function unconditionally from
MemFd::create(). This makes the main code path more readable.
Suggested-by: Nicolas Dufresne <nicolas@ndufresne.ca>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Tested-by: Milan Zamazal <mzamazal@redhat.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Unlike in C where they have been standardized since C99, variable-length
arrays in C++ are an extension supported by gcc and clang. Clang started
warning about this with -Wall in version 18:
src/libcamera/ipc_unixsocket.cpp:250:11: error: variable length arrays in C++ are a Clang extension [-Werror,-Wvla-cxx-extension]
250 | char buf[CMSG_SPACE(num * sizeof(uint32_t))];
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
One simple option is to disable the warning. However, usage of VLAs in
C++ is discouraged by some, usually due to security reasons, based on
the rationale that developers are often unaware of unintentional use of
VLAs and how they may affect the security of the code when the array
size is not properly validated.
This rationale may sound dubious, as the most commonly proposed fix is
to replace VLAs with vectors (or just arrays dynamically allocated with
new() wrapped in unique pointers), without adding any size validation.
This will not produce much better results. However, keeping the VLA
warning and converting the code to dynamic allocation may still be
slightly better, as it can prompt developers to notice VLAs and check if
size validation is required.
For these reasons, convert all VLAs to std::vector. Most of the VLAs
don't need extra size validation, as the size is bound through different
constraints (e.g. image width for line buffers). An arguable exception
may be the buffers in IPCUnixSocket::sendData() and
IPCUnixSocket::recvData() as the number of fds is not bound-checked
locally, but we will run out of file descriptors before we could
overflow the buffer size calculation.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Milan Zamazal <mzamazal@redhat.com>
Acked-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
V4L2VideoDevice is using the caps to determine which kind of buffers to
use with the video-device in 2 different cases:
1. V4L2VideoDevice::open()
2. V4L2VideoDevice::[get|try|set]Format()
And the order in which the caps are checked is different between
these 2 cases. This is a problem for /dev/video# nodes which support
both video-capture and metadata buffers. open() sets bufferType_ to
V4L2_BUF_TYPE_VIDEO_CAPTURE[_MPLANE] in this case, where as
[get|try|set]Format() will call [get|set]FormatMeta() which does not
work with V4L2_BUF_TYPE_VIDEO_CAPTURE[_MPLANE] buffers.
Switch [get|try|set]Format() to use the bufferType_ to determine on what
sort of buffers they should be operating, leaving the V4L2VideoDevice
code with only a single place where the decision is made what sort
of buffers it should operate on for a specific /dev/video# node.
This will also allow to modify open() in the future to take a bufferType
argument to allow overriding the default bufferType it selects for
/dev/video# nodes which are capable of supporting more then 1 buffer type.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
The converter interface uses the unsigned int output stream index to map
to the output frame buffers. This is cumbersome to implement new
converters because one has to keep around additional book keeping
to track the streams with their correct indexes.
The v4l2_converter_m2m and simple pipeline handler are adapted to
use the new interface. This work roped in software ISP as well,
which also seems to use indexes (although it doesn't implement converter
interface) because of a common conversionQueue_ queue used for
converter_ and swIsp_.
The logPrefix is no longer able to generate an index from a stream, and
is updated to be more expressive by reporting the stream configuration
instead, for example, reporting "1920x1080-MJPEG" in place of
"stream0".
Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Tested-by: Andrei Konovalov <andrey.konovalov.ynk@gmail.com> # sm8250 RB5
Rename the private Stream class from V4L2M2MConverter::Stream to
V4L2M2MConverter::V4L2M2MStream. This is done to improve readability
of the code when we drop the handling of stream by indexes in a
subsequent patch.
Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Currently the soft-isp outputs a single output stream. Hence,
drop the unnecessary check for stream indexes.
Another reason to drop is actually the stream indexes is meant to be
unique in outputs std::map<>, hence checking for unique stream indexes
is redundant.
Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
The streams sanity check tries to determine if all the stream indexes
passed in outputs std::map<> are unique. However, since the data
container is std::map<>, all its keys (stream indexes in this case),
are already unique.
Instead, rectify the sanity check to ensure all the framebuffers passed
in the outputs std::map<> are unique to each index. Hence, no two stream
indexes should have same framebuffer. Update the comment to reflect
the change.
Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
The YamlObject::get<T>() function template has a specialization for
double but not for float. When used in an IPA module, the issue is
caught at module load time only, when dynamic links are resolved,
causing errors such as
Failed to open IPA module shared object: /usr/lib/libcamera/ipa_rkisp1.so: undefined symbol: _ZNK9libcamera10YamlObject6GetterIfE3getERK_
Fix it by adding a float specialization. The alternative would be to use
double only in IPA modules, but the lack of enforcement at compile time
makes this dangerous.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: Stefan Klug <stefan.klug@ideasonboard.com>
In order to be more compatible with modern hardware and APIs. This
notably allows GL implementations to directly import the buffers more
often and seems to be required for Wayland.
Further more, as we already enforce a 8 byte stride, these formats work
better for clients that don't support padding - such as libwebrtc at the
time of writing.
Tested devices:
- Librem5
- PinePhone
- Thinkpad X13s
Signed-off-by: Robert Mader <robert.mader@collabora.com>
Tested-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Milan Zamazal <mzamazal@redhat.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
The YamlObject::get() function is a function template that gets fully
specialized for various types. This works fine for non-template types,
but specializing it for template types (e.g. a std::vector<U>) would
require partial template specialization, which C++ allows for classes
and variables but not functions.
To work around this problem, delegate the implementation to a new
YamlObject::Getter structure template, which will support partial
specialization.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
generateConfiguration() called validate() as a final step, causing the
stride and frameSize fields in StreamConfiguration to be filled in based
on the pixel format and width/height.
If a user application did not clear the stride field when setting up a
custom pixel format and width/height, the pipeline handler would respect
this stride and possibly overallocate buffers with a larger stride than
needed.
Fix this by removing the call to validate() completely, leaving the
stride and frameSize fields defaulting to 0. Removal of this call is
inconsequential as we hard-code a valid configuration for Raspberry Pi
platforms in generateConfiguration().
Bug: https://github.com/raspberrypi/libcamera/issues/138
Bug: https://github.com/raspberrypi/libcamera/issues/141
Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: David Plowman <david.plowman@raspberrypi.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
This way the construction of the default value of type `T`
can be delayed until it is really needed, which is useful,
for example when `T == std::string` and the default value comes
from a string literal, as the default value string would always
be constructed otherwise, even if not needed.
Signed-off-by: Barnabás Pőcze <pobrn@protonmail.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Laurent Pinchart
Daniel Scally
Milan Zamazal
will whang
Kieran Bingham
Jai Luthra
Hans de Goede
Dennis Bonke
Umang Jain
Stefan Klug
Robert Mader
Naushir Patuck
Barnabás Pőcze