ConfigDB.h

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/* Copyright (C) 2015 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * 0 A.D. is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
    CConfigDB - Load, access and store configuration variables

    TDD     :   http://www.wildfiregames.com/forum/index.php?showtopic=1125
    OVERVIEW:

    JavaScript: Check this documentation: http://trac.wildfiregames.com/wiki/Exposed_ConfigDB_Functions
*/

#ifndef INCLUDED_CONFIGDB
#define INCLUDED_CONFIGDB

#include "lib/file/vfs/vfs_path.h"
#include "ps/CStr.h"
#include "ps/Singleton.h"

// Namespace priorities: User supersedes mod supersedes system.
//                       Command-line arguments override everything.

enum EConfigNamespace
{
    CFG_DEFAULT,
    CFG_SYSTEM,
    CFG_MOD,
    CFG_USER,
    CFG_COMMAND,
    CFG_LAST
};

typedef std::vector<CStr> CConfigValueSet;

#define g_ConfigDB CConfigDB::GetSingleton()

class CConfigDB: public Singleton<CConfigDB>
{
    static std::map<CStr, CConfigValueSet> m_Map[];
    static VfsPath m_ConfigFile[];
    static bool m_HasChanges[];

public:
    CConfigDB();

    /**
     * Attempt to retrieve the value of a config variable with the given name;
     * will search CFG_COMMAND first, and then all namespaces from the specified
     * namespace down.
     */
    void GetValue(EConfigNamespace ns, const CStr& name, bool& value);
    ///@copydoc CConfigDB::GetValue
    void GetValue(EConfigNamespace ns, const CStr& name, int& value);
    ///@copydoc CConfigDB::GetValue
    void GetValue(EConfigNamespace ns, const CStr& name, float& value);
    ///@copydoc CConfigDB::GetValue
    void GetValue(EConfigNamespace ns, const CStr& name, double& value);
    ///@copydoc CConfigDB::GetValue
    void GetValue(EConfigNamespace ns, const CStr& name, std::string& value);

    /**
     * Returns true if changed with respect to last write on file
     */
    bool HasChanges(EConfigNamespace ns) const;

    void SetChanges(EConfigNamespace ns, bool value);

    /**
     * Attempt to retrieve a vector of values corresponding to the given setting;
     * will search CFG_COMMAND first, and then all namespaces from the specified
     * namespace down.
     */
    void GetValues(EConfigNamespace ns, const CStr& name, CConfigValueSet& values) const;

    /**
     * Returns the namespace that the value returned by GetValues was defined in,
     * or CFG_LAST if it wasn't defined at all.
     */
    EConfigNamespace GetValueNamespace(EConfigNamespace ns, const CStr& name) const;

    /**
     * Retrieve a map of values corresponding to settings whose names begin
     * with the given prefix;
     * will search all namespaces from default up to the specified namespace.
     */
    std::map<CStr, CConfigValueSet> GetValuesWithPrefix(EConfigNamespace ns, const CStr& prefix) const;

    /**
     * Save a config value in the specified namespace. If the config variable
     * existed the value is replaced.
     */
    void SetValueString(EConfigNamespace ns, const CStr& name, const CStr& value);

    void SetValueBool(EConfigNamespace ns, const CStr& name, const bool value);

    /**
     * Remove a config value in the specified namespace.
     */
    void RemoveValue(EConfigNamespace ns, const CStr& name);

    /**
     * Set the path to the config file used to populate the specified namespace
     * Note that this function does not actually load the config file. Use
     * the Reload() method if you want to read the config file at the same time.
     *
     * 'path': The path to the config file.
     */
    void SetConfigFile(EConfigNamespace ns, const VfsPath& path);

    /**
     * Reload the config file associated with the specified config namespace
     * (the last config file path set with SetConfigFile)
     *
     * Returns:
     *  true:   if the reload succeeded,
     *  false:  if the reload failed
     */
    bool Reload(EConfigNamespace);

    /**
     * Write the current state of the specified config namespace to the file
     * specified by 'path'
     *
     * Returns:
     *  true:   if the config namespace was successfully written to the file
     *  false:  if an error occurred
     */
    bool WriteFile(EConfigNamespace ns, const VfsPath& path) const;

    /**
     * Write the current state of the specified config namespace to the file
     * it was originally loaded from.
     *
     * Returns:
     *  true:   if the config namespace was successfully written to the file
     *  false:  if an error occurred
     */
    bool WriteFile(EConfigNamespace ns) const;

    /**
     * Write a config value to the file specified by 'path'
     *
     * Returns:
     *  true:   if the config value was successfully saved and written to the file
     *  false:  if an error occurred
     */
    bool WriteValueToFile(EConfigNamespace ns, const CStr& name, const CStr& value, const VfsPath& path);

    bool WriteValueToFile(EConfigNamespace ns, const CStr& name, const CStr& value);
};


// stores the value of the given key into <destination>. this quasi-template
// convenience wrapper on top of GetValue simplifies user code
#define CFG_GET_VAL(name, destination)\
    g_ConfigDB.GetValue(CFG_USER, name, destination)

#endif // INCLUDED_CONFIGDB