[libcamera-devel,v3,02/13] libcamera: pipeline: Add a platform configuration file helper

17945 diff mbox series

Add a new helper function PipelineHandler::configurationFile() that returns
the full path of a named configuration file. This configuration file may be read
by pipeline handlers for platform specific configuration parameters on
initialisation.

The mechanism for searching for the configuration file is similar to the IPA
configuration file:

- In the source tree if libcamera is not installed
- Otherwise in standard system locations (etc and share directories).

When stored in the source tree, configuration files shall be located in a 'data'
subdirectory of their respective pipeline handler directory.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: David Plowman <david.plowman@raspberrypi.com>
---
 include/libcamera/internal/pipeline_handler.h |  3 +
 src/libcamera/pipeline_handler.cpp            | 60 +++++++++++++++++++
 2 files changed, 63 insertions(+)

Hi,

I should note that  PipelineHandler::configurationFile() is not actually
used in
this series any more since we now only optionally load a config file if one
is
set in the environment variable.  So this commit could possibly be dropped
if we
prefer.  However, I do think it has benefits to leave it in if the config
file
was mandatory for other pipeline handlers.

Thanks,
Naush

On Tue, 6 Dec 2022 at 13:55, Naushir Patuck <naush@raspberrypi.com> wrote:

> Add a new helper function PipelineHandler::configurationFile() that returns
> the full path of a named configuration file. This configuration file may
> be read
> by pipeline handlers for platform specific configuration parameters on
> initialisation.
>
> The mechanism for searching for the configuration file is similar to the
> IPA
> configuration file:
>
> - In the source tree if libcamera is not installed
> - Otherwise in standard system locations (etc and share directories).
>
> When stored in the source tree, configuration files shall be located in a
> 'data'
> subdirectory of their respective pipeline handler directory.
>
> Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
> Reviewed-by: David Plowman <david.plowman@raspberrypi.com>
> ---
>  include/libcamera/internal/pipeline_handler.h |  3 +
>  src/libcamera/pipeline_handler.cpp            | 60 +++++++++++++++++++
>  2 files changed, 63 insertions(+)
>
> diff --git a/include/libcamera/internal/pipeline_handler.h
> b/include/libcamera/internal/pipeline_handler.h
> index ec4f662d7399..4c4dfe62a680 100644
> --- a/include/libcamera/internal/pipeline_handler.h
> +++ b/include/libcamera/internal/pipeline_handler.h
> @@ -65,6 +65,9 @@ public:
>         bool completeBuffer(Request *request, FrameBuffer *buffer);
>         void completeRequest(Request *request);
>
> +       std::string configurationFile(const std::string &subdir,
> +                                     const std::string &name) const;
> +
>         const char *name() const { return name_; }
>
>  protected:
> diff --git a/src/libcamera/pipeline_handler.cpp
> b/src/libcamera/pipeline_handler.cpp
> index cfade4908118..a515ad5ecffb 100644
> --- a/src/libcamera/pipeline_handler.cpp
> +++ b/src/libcamera/pipeline_handler.cpp
> @@ -8,6 +8,7 @@
>  #include "libcamera/internal/pipeline_handler.h"
>
>  #include <chrono>
> +#include <sys/stat.h>
>  #include <sys/sysmacros.h>
>
>  #include <libcamera/base/log.h>
> @@ -534,6 +535,65 @@ void PipelineHandler::completeRequest(Request
> *request)
>         }
>  }
>
> +/**
> + * \brief Retrieve the absolute path to a platform configuration file
> + * \param[in] subdir The pipeline handler specific subdirectory name
> + * \param[in] name The configuration file name
> + *
> + * This function locates a named platform configuration file and returns
> + * its absolute path to the pipeline handler. It searches the following
> + * directories, in order:
> + *
> + * - If libcamera is not installed, the
> src/libcamera/pipeline/<subdir>/data/
> + *   directory within the source tree ; otherwise
> + * - The system data (share/libcamera/pipeline/<subdir>) directory.
> + *
> + * The system directories are not searched if libcamera is not installed.
> + *
> + * \return The full path to the pipeline handler configuration file, or
> an empty
> + * string if no configuration file can be found
> + */
> +std::string PipelineHandler::configurationFile(const std::string &subdir,
> +                                              const std::string &name)
> const
> +{
> +       std::string confPath;
> +       struct stat statbuf;
> +       int ret;
> +
> +       std::string root = utils::libcameraSourcePath();
> +       if (!root.empty()) {
> +               /*
> +                * When libcamera is used before it is installed, load
> +                * configuration files from the source directory. The
> +                * configuration files are then located in the 'data'
> +                * subdirectory of the corresponding pipeline handler.
> +                */
> +               std::string confDir = root + "src/libcamera/pipeline/";
> +               confPath = confDir + subdir + "/data/" + name;
> +
> +               LOG(Pipeline, Info)
> +                       << "libcamera is not installed. Loading platform
> configuration file from '"
> +                       << confPath << "'";
> +
> +               ret = stat(confPath.c_str(), &statbuf);
> +               if (ret == 0 && (statbuf.st_mode & S_IFMT) == S_IFREG)
> +                       return confPath;
> +       } else {
> +               /* Else look in the system locations. */
> +               confPath = std::string(LIBCAMERA_DATA_DIR)
> +                               + "/pipeline/" + subdir + '/' + name;
> +               ret = stat(confPath.c_str(), &statbuf);
> +               if (ret == 0 && (statbuf.st_mode & S_IFMT) == S_IFREG)
> +                       return confPath;
> +       }
> +
> +       LOG(Pipeline, Error)
> +               << "Configuration file '" << confPath
> +               << "' not found for pipeline handler '" <<
> PipelineHandler::name() << "'";
> +
> +       return std::string();
> +}
> +
>  /**
>   * \brief Register a camera to the camera manager and pipeline handler
>   * \param[in] camera The camera to be added
> --
> 2.25.1
>
>