Config.h

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/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */
 
#ifndef META_OCEAN_BASE_CONFIG_H
#define META_OCEAN_BASE_CONFIG_H
 
#include "ocean/base/Base.h"
#include "ocean/base/Timestamp.h"
 
#include <vector>
 
#ifdef __APPLE__
    #ifdef TYPE_BOOL
        #undef TYPE_BOOL
    #endif
#endif
 
namespace Ocean
{
 
/**
 * This class implements an application or module configuration toolkit.
 * Each configuration toolkit holds a value tree.<br>
 * Different single value types are supported like e.g. boolean, integer or strings.<br>
 * Furthermore, groups can be specified holding an arbitrary number of sub values.<br>
 * Values names does not need to be unique. Therefore, a group can hold several sub values with the same name.<br>
 * Also, values with the same name can have different value types.<br>
 * However, this is an abstract configuration object and therefore should be used as platform independent interface only.<br>
 * Use e.g. file configuration or a registry configuration object instead.
 * The entire object is not thread-safe.
 * @ingroup base
 */
class OCEAN_BASE_EXPORT Config
{
    public:
 
        /**
         * Definition of different value types.
         */
        enum ValueType
        {
            /// Invalid value type.
            TYPE_INVALID,
            /// Undefined value type.
            TYPE_UNDEFINED,
            /// Boolean value type.
            TYPE_BOOL,
            /// Integer value type.
            TYPE_INT,
            /// Number value type.
            TYPE_NUMBER,
            /// String value type.
            TYPE_STRING,
            /// Multi boolean value type.
            TYPE_MULTI_BOOL,
            /// Multi integer value type.
            TYPE_MULTI_INT,
            /// Multi number value type.
            TYPE_MULTI_NUMBER,
            /// Multi string value type.
            TYPE_MULTI_STRING,
            /// Group value type.
            TYPE_GROUP
        };
 
    public:
 
        /**
         * This class implements a configuration value.
         * Each value can represent a single parameter or a grouping object.<br>
         */
        class OCEAN_BASE_EXPORT Value
        {
            friend class Config;
 
            public:
 
                /**
                 * Returns the type of this value.
                 * @return Value type
                 */
                virtual ValueType type() const;
 
                /**
                 * Returns whether this value holds a multi type.
                 * @return True, if so
                 */
                virtual bool isMultiType() const;
 
                /**
                 * Returns the number of sub values.
                 * @return Sub value number
                 */
                virtual unsigned int values() const;
 
                /**
                 * Returns the number of sub values with a given name.
                 * @param name The name of the sub values to return
                 * @return Sub value number
                 */
                virtual unsigned int values(const std::string& name) const;
 
                /**
                 * Returns whether this value holds at least one specified sub value.
                 * @param name The name of the sub value to check
                 * @return True, if so
                 */
                virtual bool exist(const std::string& name) const;
 
                /**
                 * Returns a sub value specified by it's name and it's index if more than one value exists with the same name.
                 * @param name The name of the value to return
                 * @param index The index within those sub values with the specified name
                 * @return Sub value
                 */
                virtual Value& value(const std::string& name, const unsigned int index = 0u);
 
                /**
                 * Returns a sub value specified by it's name and it's index if more than one value exists with the same name.
                 * @param name The name of the value to return
                 * @param index The index within those sub values with the specified name
                 * @param value Resulting sub value
                 * @return True, if the value exists
                 */
                virtual bool value(const std::string& name, const unsigned int index, Value** value);
 
                /**
                 * Returns a sub value specified by it's index.
                 * @param index The index of the sub value to return
                 * @param name Resulting name of the returning value
                 * @return Sub value
                 */
                virtual Value& value(const unsigned int index, std::string& name);
 
                /**
                 * Returns a sub value specified by it's index.
                 * @param index The index of the sub value to return
                 * @param name Resulting name of the returning value
                 * @param value Resulting sub value
                 * @return True, if the value exists
                 */
                virtual bool value(const unsigned int index, std::string& name, Value** value);
 
                /**
                 * Adds a new sub value specified by it's name.
                 * @param name The name of the sub value to create
                 * @return New sub value
                 */
                virtual Value& add(const std::string& name);
 
                /**
                 * Returns this value as boolean.
                 * @param value Default value which will be returned if this value holds no boolean
                 * @return Internal value
                 */
                virtual bool operator()(const bool value) const;
 
                /**
                 * Returns this value as integer.
                 * @param value Default value which will be returned if this value holds no integer
                 * @return Internal value
                 */
                virtual int operator()(const int value) const;
 
                /**
                 * Returns this value as number.
                 * @param value Default value which will be returned if this value holds no number
                 * @return Internal value
                 */
                virtual double operator()(const double value) const;
 
                /**
                 * Returns this value as string.
                 * @param value Default value which will be returned if this value holds no string
                 * @return Internal value
                 */
                inline std::string operator()(const char* value) const;
 
                /**
                 * Returns this value as string.
                 * @param value Default value which will be returned if this value holds no string
                 * @return Internal value
                 */
                virtual std::string operator()(const std::string& value) const;
 
                /**
                 * Returns this value as multi boolean.
                 * @param value Default value which will be returned if this value holds no boolean
                 * @return Internal value
                 */
                virtual std::vector<bool> operator()(const std::vector<bool>& value) const;
 
                /**
                 * Returns this value as multi integer.
                 * @param value Default value which will be returned if this value holds no integer
                 * @return Internal value
                 */
                virtual std::vector<int> operator()(const std::vector<int>& value) const;
 
                /**
                 * Returns this value as multi number.
                 * @param value Default value which will be returned if this value holds no number
                 * @return Internal value
                 */
                virtual std::vector<double> operator()(const std::vector<double>& value) const;
 
                /**
                 * Returns this value as multi string.
                 * @param value Default value which will be returned if this value holds no string
                 * @return Internal value
                 */
                virtual Strings operator()(const Strings& value) const;
 
                /**
                 * Sets this value as boolean.
                 * @param value The value to set
                 * @return True, if succeeded
                 */
                virtual bool operator=(const bool value);
 
                /**
                 * Sets this value as integer.
                 * @param value The value to set
                 * @return True, if succeeded
                 */
                virtual bool operator=(const int value);
 
                /**
                 * Sets this value as number.
                 * @param value The value to set
                 * @return True, if succeeded
                 */
                virtual bool operator=(const double value);
 
                /**
                 * Sets this value as string.
                 * @param value The value to set
                 * @return True, if succeeded
                 */
                inline bool operator=(const char* value);
 
                /**
                 * Sets this value as string.
                 * @param value The value to set
                 * @return True, if succeeded
                 */
                virtual bool operator=(const std::string& value);
 
                /**
                 * Sets this value as multi boolean.
                 * @param values The values to set
                 * @return True, if succeeded
                 */
                virtual bool operator=(const std::vector<bool>& values);
 
                /**
                 * Sets this value as multi integer.
                 * @param values The values to set
                 * @return True, if succeeded
                 */
                virtual bool operator=(const std::vector<int>& values);
 
                /**
                 * Sets this value as multi number.
                 * @param values The values to set
                 * @return True, if succeeded
                 */
                virtual bool operator=(const std::vector<double>& values);
 
                /**
                 * Sets this value as multi string.
                 * @param values The values to set
                 * @return True, if succeeded
                 */
                virtual bool operator=(const Strings& values);
 
                /**
                 * Returns the first sub value specified by it's name or creates a new value if no existing.
                 * @param name The name of the sub-value to return
                 * @return Specified sub value
                 */
                virtual Value& operator[](const std::string& name);
 
            protected:
 
                /**
                 * Creates a new value object.
                 */
                Value() = default;
 
                /**
                 * Default copy constructor.
                 * @param value The value to copied
                 */
                Value(const Value& value) = default;
 
                /**
                 * Destructs a value object.
                 */
                virtual ~Value() = default;
 
            protected:
 
                /// Value type.
                ValueType valueType_ = TYPE_INVALID;
        };
 
    public:
 
        /**
         * Destructs a configuration toolkit.
         */
        virtual ~Config();
 
        /**
         * Reads / loads all values of this configuration.
         * @return True, if succeeded
         */
        virtual bool read();
 
        /**
         * Writes / saves all values of this configuration.
         * @return True, if succeeded
         */
        virtual bool write();
 
        /**
         * Returns the timestamp of the last write execution.
         * @return Most recent write timestamp
         */
        inline Timestamp writeTimestamp() const;
 
        /**
         * Returns the number of sub values.
         * @return Sub value number
         */
        virtual unsigned int values() const;
 
        /**
         * Returns the number of sub values with a given name.
         * @param name The name of the sub values to return
         * @return Sub value number
         */
        virtual unsigned int values(const std::string& name) const;
 
        /**
         * Returns whether this value holds at least one specified sub value.
         * @param name The name of the sub value to check
         * @return True, if so
         */
        virtual bool exist(const std::string& name) const;
 
        /**
         * Returns a sub value specified by it's index.
         * @param index The index of the sub value to return
         * @param name Resulting name of the returning value
         * @return Sub value
         */
        virtual Value& value(const unsigned int index, std::string& name);
 
        /**
         * Returns a sub value specified by it's index.
         * @param index The index of the sub value to return
         * @param name Resulting name of the returning value
         * @param value Resulting sub value
         * @return True, if the value exists
         */
        virtual bool value(const unsigned int index, std::string& name, Value** value);
 
        /**
         * Returns a sub value specified by it's name and it's index if more than one value exists with the same name.
         * @param name The name of the value to return
         * @param index The index within those sub values with the specified name
         * @param value Resulting sub value
         * @return True, if the value exists
         */
        virtual bool value(const std::string& name, const unsigned int index, Value** value);
 
        /**
         * Returns a sub value specified by it's name and it's index if more than one value exists with the same name.
         * @param name The name of the value to return
         * @param index The index within those sub values with the specified name
         * @return Sub value
         */
        virtual Value& value(const std::string& name, const unsigned int index = 0);
 
        /**
         * Adds a new sub value specified by it's name.
         * @param name The name of the sub value to create
         * @return New sub value
         */
        virtual Value& add(const std::string& name);
 
        /**
         * Returns the first sub value specified by it's name or creates a new one if not existing.
         * @param name The name of the sub value to return
         * @return Specified sub value
         */
        virtual Value& operator[](const std::string& name);
 
    protected:
 
        /**
         * Creates a new configuration toolkit
         */
        Config();
 
        /**
         * Disabled copy constructor.
         * @param config Object which would be copied
         */
        Config(const Config& config) = delete;
 
        /**
         * Disabled copy operator.
         * @param config Object which would be copied
         * @return Reference to this object
         */
        Config& operator=(const Config& config) = delete;
 
        /**
         * Returns the default value holding no data.
         * @note This function is not virtual by intention. Derived classes are supposed to override it and have it return their derived value type.
         * @return The default value holding no data.
         */
        static Value& nullValue();
 
    protected:
 
        /// Holds the timestamp of the most recent write execution.
        Timestamp writeTimestamp_;
};
 
inline std::string Config::Value::operator()(const char* value) const
{
    return (*this)(std::string(value));
}
 
inline bool Config::Value::operator=(const char* value)
{
    return (*this) = std::string(value);
}
 
inline Timestamp Config::writeTimestamp() const
{
    return writeTimestamp_;
}
 
}
 
#endif // META_OCEAN_BASE_CONFIG_H