| Message ID | 20250911092945.16517-4-mzamazal@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series |
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| Related | show |
Hi Milan, Thanks for the patch. Quoting Milan Zamazal (2025-09-11 18:29:33) > Let's add some helpers to make accessing simple configuration values > simpler. The helpers are used in the followup patches. > > GlobalConfiguration::option ensures that no value is returned rather > than a value of YamlObject::empty. > > Signed-off-by: Milan Zamazal <mzamazal@redhat.com> Looks good to me. Reviewed-by: Paul Elder <paul.elder@ideasonboard.com> > --- > .../libcamera/internal/global_configuration.h | 28 ++++++ > src/libcamera/global_configuration.cpp | 99 +++++++++++++++++++ > 2 files changed, 127 insertions(+) > > diff --git a/include/libcamera/internal/global_configuration.h b/include/libcamera/internal/global_configuration.h > index f695498c4..8d09517ed 100644 > --- a/include/libcamera/internal/global_configuration.h > +++ b/include/libcamera/internal/global_configuration.h > @@ -8,6 +8,11 @@ > #pragma once > > #include <filesystem> > +#include <optional> > +#include <string> > +#include <string_view> > + > +#include <libcamera/base/utils.h> > > #include "libcamera/internal/yaml_parser.h" > > @@ -23,6 +28,29 @@ public: > unsigned int version() const; > Configuration configuration() const; > > + template<typename T> > + std::optional<T> option( > + const std::initializer_list<std::string_view> confPath) const > + { > + const YamlObject *c = &configuration(); > + for (auto part : confPath) { > + c = &(*c)[part]; > + if (!*c) > + return {}; > + } > + return c->get<T>(); > + } > + > + std::optional<std::vector<std::string>> listOption( > + const std::initializer_list<std::string_view> confPath) const; > + std::optional<std::string> envOption( > + const char *const envVariable, > + const std::initializer_list<std::string_view> confPath) const; > + std::optional<std::vector<std::string>> envListOption( > + const char *const envVariable, > + const std::initializer_list<std::string_view> confPath, > + const std::string delimiter = ":") const; > + > private: > bool loadFile(const std::filesystem::path &fileName); > void load(); > diff --git a/src/libcamera/global_configuration.cpp b/src/libcamera/global_configuration.cpp > index d02668111..592edcf30 100644 > --- a/src/libcamera/global_configuration.cpp > +++ b/src/libcamera/global_configuration.cpp > @@ -8,8 +8,12 @@ > #include "libcamera/internal/global_configuration.h" > > #include <filesystem> > +#include <memory> > +#include <optional> > +#include <string> > #include <string_view> > #include <sys/types.h> > +#include <vector> > > #include <libcamera/base/file.h> > #include <libcamera/base/log.h> > @@ -43,6 +47,12 @@ LOG_DEFINE_CATEGORY(Configuration) > * If the first found configuration file cannot be opened or parsed, an error is > * reported and no configuration file is used. This is to prevent libcamera from > * using an unintended configuration file. > + * > + * The configuration can be accessed using the provided helpers. Namely > + * GlobalConfiguration::option(), GlobalConfiguration::envOption(), > + * GlobalConfiguration::listOption(), and GlobalConfiguration::envListOption() > + * to access individual options, or GlobalConfiguration::configuration() to > + * access the whole configuration. > */ > > bool GlobalConfiguration::loadFile(const std::filesystem::path &fileName) > @@ -110,6 +120,95 @@ GlobalConfiguration::GlobalConfiguration() > * the underlying type. > */ > > +/** > + * \fn std::optional<T> GlobalConfiguration::option(const std::initializer_list<std::string_view> &confPath) const > + * \brief Return value of the configuration option identified by \a confPath > + * \param[in] confPath Sequence of the YAML section names (excluding > + * `configuration') leading to the requested option > + * \return The value of the configuration item corresponding to \a confPath if > + * it exists in the configuration file, or no value otherwise > + */ > + > +/** > + * \brief Return values of the configuration option identified by \a confPath > + * \tparam T The type of the retrieved configuration value > + * \param[in] confPath Sequence of the YAML section names (excluding > + * `configuration') leading to the requested list option, separated by dots > + * \return A vector of strings or no value if not found > + */ > +std::optional<std::vector<std::string>> GlobalConfiguration::listOption( > + const std::initializer_list<std::string_view> confPath) const > +{ > + const YamlObject *c = &configuration(); > + for (auto part : confPath) { > + c = &(*c)[part]; > + if (!*c) > + return {}; > + } > + return c->getList<std::string>(); > +} > + > +/** > + * \brief Return value of environment variable with a fallback on the configuration file > + * \param[in] envVariable Environment variable to get the value from > + * \param[in] confPath The sequence of YAML section names to fall back on when > + * \a envVariable is unavailable > + * > + * This helper looks first at the given environment variable and if it is > + * defined then it returns its value (even if it is empty). Otherwise it looks > + * for \a confPath the same way as in GlobalConfiguration::option. Only string > + * values are supported. > + * > + * \note Support for using environment variables to configure libcamera behavior > + * is provided here mostly for backward compatibility reasons. Introducing new > + * configuration environment variables is discouraged. > + * > + * \return The value retrieved from the given environment if it is set, > + * otherwise the value from the configuration file if it exists, or no value if > + * it does not > + */ > +std::optional<std::string> GlobalConfiguration::envOption( > + const char *envVariable, > + const std::initializer_list<std::string_view> confPath) const > +{ > + const char *envValue = utils::secure_getenv(envVariable); > + if (envValue) > + return std::optional{ std::string{ envValue } }; > + return option<std::string>(confPath); > +} > + > +/** > + * \brief Return values of the configuration option from a file or environment > + * \param[in] envVariable Environment variable to get the value from > + * \param[in] confPath The same as in GlobalConfiguration::option > + * \param[in] delimiter Items separator in the environment variable > + * > + * This helper looks first at the given environment variable and if it is > + * defined (even if it is empty) then it splits its value by semicolons and > + * returns the resulting list of strings. Otherwise it looks for \a confPath the > + * same way as in GlobalConfiguration::option, value of which must be a list of > + * strings. > + * > + * \note Support for using environment variables to configure libcamera behavior > + * is provided here mostly for backward compatibility reasons. Introducing new > + * configuration environment variables is discouraged. > + * > + * \return A vector of strings retrieved from the given environment option or > + * configuration file or no value if not found; the vector may be empty > + */ > +std::optional<std::vector<std::string>> GlobalConfiguration::envListOption( > + const char *const envVariable, > + const std::initializer_list<std::string_view> confPath, > + const std::string delimiter) const > +{ > + const char *envValue = utils::secure_getenv(envVariable); > + if (envValue) { > + auto items = utils::split(envValue, delimiter); > + return std::vector<std::string>(items.begin(), items.end()); > + } > + return listOption(confPath); > +} > + > /** > * \brief Return configuration version > * > -- > 2.51.0 >
diff --git a/include/libcamera/internal/global_configuration.h b/include/libcamera/internal/global_configuration.h index f695498c4..8d09517ed 100644 --- a/include/libcamera/internal/global_configuration.h +++ b/include/libcamera/internal/global_configuration.h @@ -8,6 +8,11 @@ #pragma once #include <filesystem> +#include <optional> +#include <string> +#include <string_view> + +#include <libcamera/base/utils.h> #include "libcamera/internal/yaml_parser.h" @@ -23,6 +28,29 @@ public: unsigned int version() const; Configuration configuration() const; + template<typename T> + std::optional<T> option( + const std::initializer_list<std::string_view> confPath) const + { + const YamlObject *c = &configuration(); + for (auto part : confPath) { + c = &(*c)[part]; + if (!*c) + return {}; + } + return c->get<T>(); + } + + std::optional<std::vector<std::string>> listOption( + const std::initializer_list<std::string_view> confPath) const; + std::optional<std::string> envOption( + const char *const envVariable, + const std::initializer_list<std::string_view> confPath) const; + std::optional<std::vector<std::string>> envListOption( + const char *const envVariable, + const std::initializer_list<std::string_view> confPath, + const std::string delimiter = ":") const; + private: bool loadFile(const std::filesystem::path &fileName); void load(); diff --git a/src/libcamera/global_configuration.cpp b/src/libcamera/global_configuration.cpp index d02668111..592edcf30 100644 --- a/src/libcamera/global_configuration.cpp +++ b/src/libcamera/global_configuration.cpp @@ -8,8 +8,12 @@ #include "libcamera/internal/global_configuration.h" #include <filesystem> +#include <memory> +#include <optional> +#include <string> #include <string_view> #include <sys/types.h> +#include <vector> #include <libcamera/base/file.h> #include <libcamera/base/log.h> @@ -43,6 +47,12 @@ LOG_DEFINE_CATEGORY(Configuration) * If the first found configuration file cannot be opened or parsed, an error is * reported and no configuration file is used. This is to prevent libcamera from * using an unintended configuration file. + * + * The configuration can be accessed using the provided helpers. Namely + * GlobalConfiguration::option(), GlobalConfiguration::envOption(), + * GlobalConfiguration::listOption(), and GlobalConfiguration::envListOption() + * to access individual options, or GlobalConfiguration::configuration() to + * access the whole configuration. */ bool GlobalConfiguration::loadFile(const std::filesystem::path &fileName) @@ -110,6 +120,95 @@ GlobalConfiguration::GlobalConfiguration() * the underlying type. */ +/** + * \fn std::optional<T> GlobalConfiguration::option(const std::initializer_list<std::string_view> &confPath) const + * \brief Return value of the configuration option identified by \a confPath + * \param[in] confPath Sequence of the YAML section names (excluding + * `configuration') leading to the requested option + * \return The value of the configuration item corresponding to \a confPath if + * it exists in the configuration file, or no value otherwise + */ + +/** + * \brief Return values of the configuration option identified by \a confPath + * \tparam T The type of the retrieved configuration value + * \param[in] confPath Sequence of the YAML section names (excluding + * `configuration') leading to the requested list option, separated by dots + * \return A vector of strings or no value if not found + */ +std::optional<std::vector<std::string>> GlobalConfiguration::listOption( + const std::initializer_list<std::string_view> confPath) const +{ + const YamlObject *c = &configuration(); + for (auto part : confPath) { + c = &(*c)[part]; + if (!*c) + return {}; + } + return c->getList<std::string>(); +} + +/** + * \brief Return value of environment variable with a fallback on the configuration file + * \param[in] envVariable Environment variable to get the value from + * \param[in] confPath The sequence of YAML section names to fall back on when + * \a envVariable is unavailable + * + * This helper looks first at the given environment variable and if it is + * defined then it returns its value (even if it is empty). Otherwise it looks + * for \a confPath the same way as in GlobalConfiguration::option. Only string + * values are supported. + * + * \note Support for using environment variables to configure libcamera behavior + * is provided here mostly for backward compatibility reasons. Introducing new + * configuration environment variables is discouraged. + * + * \return The value retrieved from the given environment if it is set, + * otherwise the value from the configuration file if it exists, or no value if + * it does not + */ +std::optional<std::string> GlobalConfiguration::envOption( + const char *envVariable, + const std::initializer_list<std::string_view> confPath) const +{ + const char *envValue = utils::secure_getenv(envVariable); + if (envValue) + return std::optional{ std::string{ envValue } }; + return option<std::string>(confPath); +} + +/** + * \brief Return values of the configuration option from a file or environment + * \param[in] envVariable Environment variable to get the value from + * \param[in] confPath The same as in GlobalConfiguration::option + * \param[in] delimiter Items separator in the environment variable + * + * This helper looks first at the given environment variable and if it is + * defined (even if it is empty) then it splits its value by semicolons and + * returns the resulting list of strings. Otherwise it looks for \a confPath the + * same way as in GlobalConfiguration::option, value of which must be a list of + * strings. + * + * \note Support for using environment variables to configure libcamera behavior + * is provided here mostly for backward compatibility reasons. Introducing new + * configuration environment variables is discouraged. + * + * \return A vector of strings retrieved from the given environment option or + * configuration file or no value if not found; the vector may be empty + */ +std::optional<std::vector<std::string>> GlobalConfiguration::envListOption( + const char *const envVariable, + const std::initializer_list<std::string_view> confPath, + const std::string delimiter) const +{ + const char *envValue = utils::secure_getenv(envVariable); + if (envValue) { + auto items = utils::split(envValue, delimiter); + return std::vector<std::string>(items.begin(), items.end()); + } + return listOption(confPath); +} + /** * \brief Return configuration version *
Let's add some helpers to make accessing simple configuration values simpler. The helpers are used in the followup patches. GlobalConfiguration::option ensures that no value is returned rather than a value of YamlObject::empty. Signed-off-by: Milan Zamazal <mzamazal@redhat.com> --- .../libcamera/internal/global_configuration.h | 28 ++++++ src/libcamera/global_configuration.cpp | 99 +++++++++++++++++++ 2 files changed, 127 insertions(+)