cppfig::Configuration< Schema, SerializerT, ThreadPolicy > Class Template Reference

Main configuration manager. More...

#include <configuration.h>

Inheritance diagram for cppfig::Configuration< Schema, SerializerT, ThreadPolicy >:

Collaboration diagram for cppfig::Configuration< Schema, SerializerT, ThreadPolicy >:

Public Types
using	serializer_type = SerializerT
using	data_type = Value
Public Types inherited from cppfig::IConfigurationProvider< Derived, Schema >
using	schema_type = Schema

Public Member Functions
	Configuration (std::string file_path)
	Creates a configuration manager with a file path.
template<IsSetting S> requires (Schema::template has_setting<S>)
auto	GetImpl () const -> typename S::value_type
	Gets the value for a setting type.
template<IsSetting S> requires (Schema::template has_setting<S>)
auto	IsOverriddenImpl () const -> bool
	Reports whether an environment variable is overriding a setting.
template<IsSetting S> requires (Schema::template has_setting<S>)
auto	SetImpl (typename S::value_type value) -> Status
	Sets the value for a setting type.
auto	LoadImpl () -> Status
	Loads configuration from the file.
auto	SaveImpl () const -> Status
	Saves the current configuration to the file.
auto	DiffImpl () const -> ConfigDiff
	Returns the diff between file values and defaults.
auto	ValidateAllImpl () const -> Status
	Validates all current values against their validators.
auto	GetFilePathImpl () const -> std::string_view
	Returns the file path.
auto	GetFileValues () const -> Value
	Returns a snapshot of the current file values.
auto	GetDefaults () const -> Value
	Returns a snapshot of the default values.
Public Member Functions inherited from cppfig::IConfigurationProvider< Derived, Schema >
template<IsSetting S> requires (Schema::template has_setting<S>)
auto	Get () const -> typename S::value_type
	Gets the value for a setting type.
template<IsSetting S> requires (Schema::template has_setting<S>)
auto	Set (typename S::value_type value) -> Status
	Sets the value for a setting type.
template<IsSetting S> requires (Schema::template has_setting<S>)
auto	IsOverridden () const -> bool
	Reports whether an environment variable is overriding a setting.
auto	Load () -> Status
	Loads configuration from the file.
auto	Save () const -> Status
	Saves the current configuration to the file.
auto	Diff () const -> ConfigDiff
	Returns the diff between file values and defaults.
auto	ValidateAll () const -> Status
	Validates all current values against their validators.
auto	GetFilePath () const -> std::string_view
	Returns the file path.

Additional Inherited Members
Protected Member Functions inherited from cppfig::IConfigurationProvider< Derived, Schema >
	IConfigurationProvider ()=default
	~IConfigurationProvider ()=default
	IConfigurationProvider (const IConfigurationProvider &)=default
	IConfigurationProvider (IConfigurationProvider &&)=default
auto	operator= (const IConfigurationProvider &) -> IConfigurationProvider &=default
auto	operator= (IConfigurationProvider &&) -> IConfigurationProvider &=default

Detailed Description

template<typename Schema, Serializer SerializerT = ConfSerializer, typename ThreadPolicy = SingleThreadedPolicy>
class cppfig::Configuration< Schema, SerializerT, ThreadPolicy >

Main configuration manager.

This class manages configuration values with:

• Compile-time type-safe access via setting types
• Environment variable overrides
• Validation
• Automatic file creation with defaults
• Schema migration (adding new settings)
• Optional thread safety via a pluggable ThreadPolicy

Thread Safety: By default, the class uses SingleThreadedPolicy (zero overhead). For concurrent access from multiple threads, specify MultiThreadedPolicy:

// Single-threaded (default, zero overhead):
cppfig::Configuration<MySchema> config("config.json");
 
// Thread-safe (reader-writer locking):
cppfig::Configuration<MySchema, cppfig::JsonSerializer, cppfig::MultiThreadedPolicy>
    config("config.json");

With MultiThreadedPolicy:

• Multiple threads may call Get concurrently (shared/reader lock).
• Calls to Set, Load mutate internal state under an exclusive/writer lock.
• Save also takes the exclusive lock: it rewrites the file, so concurrent savers would race over the same path.
• Diff and ValidateAll acquire a shared/reader lock.
• Validation in Set is performed before acquiring the exclusive lock.

Usage:

// Define settings
struct AppName {
    static constexpr std::string_view path = "app.name";
    using value_type = std::string;
    static auto default_value() -> std::string { return "MyApp"; }
};
 
struct ServerPort {
    static constexpr std::string_view path = "server.port";
    static constexpr std::string_view env_override = "SERVER_PORT";
    using value_type = int;
    static auto default_value() -> int { return 8080; }
    static auto validator() -> Validator<int> { return Range(1, 65535); }
};
 
// Create schema and configuration
using MySchema = ConfigSchema<AppName, ServerPort>;
Configuration<MySchema> config("config.json");
 
// Load and use
config.Load();
std::string name = config.Get<AppName>();
int port = config.Get<ServerPort>();
config.Set<ServerPort>(9000);
config.Save();

Template Parameters

Schema	The ConfigSchema type defining all settings.
SerializerT	The serializer to use (defaults to ConfSerializer).
ThreadPolicy	The threading policy (defaults to SingleThreadedPolicy). For type-erased access, wrap an instance in VirtualConfigAdapter rather than deriving from IConfigurationProviderVirtual here: a virtual base would put a vptr on every configuration, including the single-threaded, non-polymorphic default.

Member Typedef Documentation

data_type

template<typename Schema , Serializer SerializerT = ConfSerializer, typename ThreadPolicy = SingleThreadedPolicy>

using cppfig::Configuration< Schema, SerializerT, ThreadPolicy >::data_type = Value

serializer_type

template<typename Schema , Serializer SerializerT = ConfSerializer, typename ThreadPolicy = SingleThreadedPolicy>

using cppfig::Configuration< Schema, SerializerT, ThreadPolicy >::serializer_type = SerializerT

Constructor & Destructor Documentation

Configuration()

template<typename Schema , Serializer SerializerT = ConfSerializer, typename ThreadPolicy = SingleThreadedPolicy>

cppfig::Configuration< Schema, SerializerT, ThreadPolicy >::Configuration ( std::string  file_path )

inlineexplicit

Creates a configuration manager with a file path.

Parameters

file_path

Path to the configuration file.

Member Function Documentation

DiffImpl()

template<typename Schema , Serializer SerializerT = ConfSerializer, typename ThreadPolicy = SingleThreadedPolicy>

auto cppfig::Configuration< Schema, SerializerT, ThreadPolicy >::DiffImpl ( ) const -> ConfigDiff

inline

Returns the diff between file values and defaults.

Thread safety: acquires a shared (reader) lock.

GetDefaults()

template<typename Schema , Serializer SerializerT = ConfSerializer, typename ThreadPolicy = SingleThreadedPolicy>

auto cppfig::Configuration< Schema, SerializerT, ThreadPolicy >::GetDefaults ( ) const -> Value

inline

Returns a snapshot of the default values.

Thread safety: defaults_ is immutable after construction — safe to call concurrently without synchronization.

GetFilePathImpl()

template<typename Schema , Serializer SerializerT = ConfSerializer, typename ThreadPolicy = SingleThreadedPolicy>

auto cppfig::Configuration< Schema, SerializerT, ThreadPolicy >::GetFilePathImpl ( ) const -> std::string_view

inline

Returns the file path.

Thread safety: file_path_ is immutable after construction — no lock needed.

GetFileValues()

template<typename Schema , Serializer SerializerT = ConfSerializer, typename ThreadPolicy = SingleThreadedPolicy>

auto cppfig::Configuration< Schema, SerializerT, ThreadPolicy >::GetFileValues ( ) const -> Value

inline

Returns a snapshot of the current file values.

Returned by value: handing out a reference to file_values_ let it escape the lock that guards it, so a reader could observe a tree being mutated by Set or Load.

Thread safety: acquires a shared (reader) lock.

GetImpl()

template<typename Schema , Serializer SerializerT = ConfSerializer, typename ThreadPolicy = SingleThreadedPolicy>

template<IsSetting S>
requires (Schema::template has_setting<S>)

auto cppfig::Configuration< Schema, SerializerT, ThreadPolicy >::GetImpl ( ) const -> typename S::value_type

inline

Gets the value for a setting type.

Resolution order:

1. Environment variable (if configured)
2. File value (if present)
3. Default value

Thread safety: acquires a shared (reader) lock when reading file values.

IsOverriddenImpl()

template<typename Schema , Serializer SerializerT = ConfSerializer, typename ThreadPolicy = SingleThreadedPolicy>

template<IsSetting S>
requires (Schema::template has_setting<S>)

auto cppfig::Configuration< Schema, SerializerT, ThreadPolicy >::IsOverriddenImpl ( ) const -> bool

inline

Reports whether an environment variable is overriding a setting.

An override wins over the file value, so Set on such a setting is recorded and saved but will not be what Get returns. Callers that need to know can ask before writing.

LoadImpl()

template<typename Schema , Serializer SerializerT = ConfSerializer, typename ThreadPolicy = SingleThreadedPolicy>

auto cppfig::Configuration< Schema, SerializerT, ThreadPolicy >::LoadImpl ( ) -> Status

inline

Loads configuration from the file.

Thread safety: acquires an exclusive (writer) lock for the entire operation because it mutates file_values_.

SaveImpl()

template<typename Schema , Serializer SerializerT = ConfSerializer, typename ThreadPolicy = SingleThreadedPolicy>

auto cppfig::Configuration< Schema, SerializerT, ThreadPolicy >::SaveImpl ( ) const -> Status

inline

Saves the current configuration to the file.

Thread safety: acquires an exclusive (writer) lock. Although only file_values_ is read, the call also rewrites the file, and two threads holding a shared lock would race over the same path. Serializing saves costs nothing next to the file I/O they perform.

SetImpl()

template<typename Schema , Serializer SerializerT = ConfSerializer, typename ThreadPolicy = SingleThreadedPolicy>

template<IsSetting S>
requires (Schema::template has_setting<S>)

auto cppfig::Configuration< Schema, SerializerT, ThreadPolicy >::SetImpl ( typename S::value_type  value ) -> Status

inline

Sets the value for a setting type.

The value is stored and will be written by Save. If an environment override is shadowing the setting, Get will keep returning the override; that is logged, and IsOverridden reports it up front.

Thread safety: validation runs without holding any lock; the actual mutation of internal state acquires an exclusive (writer) lock.

ValidateAllImpl()

template<typename Schema , Serializer SerializerT = ConfSerializer, typename ThreadPolicy = SingleThreadedPolicy>

auto cppfig::Configuration< Schema, SerializerT, ThreadPolicy >::ValidateAllImpl ( ) const -> Status

inline

Validates all current values against their validators.

Thread safety: acquires a shared (reader) lock.

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The documentation for this class was generated from the following file:

• src/cppfig/configuration.h