settings.h

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// Luanti
// SPDX-License-Identifier: LGPL-2.1-or-later
// Copyright (C) 2010-2013 celeron55, Perttu Ahola <celeron55@gmail.com>
 
#pragma once
 
#include "irrlichttypes_bloated.h"
#include "util/string.h"
#include "util/basic_macros.h"
#include <string>
#include <set>
#include <map>
#include <mutex>
 
class Settings;
struct NoiseParams;
 
// Global objects
extern Settings *g_settings; // Same as Settings::getLayer(SL_GLOBAL);
extern std::string g_settings_path;
 
// Type for a settings changed callback function
typedef void (*SettingsChangedCallback)(const std::string &name, void *data);
 
typedef std::vector<
        std::pair<
                SettingsChangedCallback,
                void *
        >
> SettingsCallbackList;
 
typedef std::unordered_map<std::string, SettingsCallbackList> SettingsCallbackMap;
 
enum ValueType {
        VALUETYPE_STRING,
        VALUETYPE_FLAG // Doesn't take any arguments
};
 
enum SettingsParseEvent {
        SPE_NONE,
        SPE_INVALID,
        SPE_COMMENT,
        SPE_KVPAIR,
        SPE_END,
        SPE_GROUP,
        SPE_MULTILINE,
};
 
// Describes the global setting layers, SL_GLOBAL is where settings are read from
enum SettingsLayer {
        SL_DEFAULTS,
        SL_GAME,
        SL_GLOBAL,
        SL_TOTAL_COUNT
};
 
// Implements the hierarchy a settings object may be part of
class SettingsHierarchy {
public:
        /*
         * A settings object that may be part of another hierarchy can
         * occupy the index 0 as a fallback. If not set you can use 0 on your own.
         */
        SettingsHierarchy(Settings *fallback = nullptr);
 
        DISABLE_CLASS_COPY(SettingsHierarchy)
 
        Settings *getLayer(int layer) const;
 
private:
        friend class Settings;
        Settings *getParent(int layer) const;
        void onLayerCreated(int layer, Settings *obj);
        void onLayerRemoved(int layer);
 
        std::vector<Settings*> layers;
};
 
struct ValueSpec {
        ValueSpec(ValueType a_type, const char *a_help=NULL)
        {
                type = a_type;
                help = a_help;
        }
 
        ValueType type;
        const char *help;
};
 
struct SettingsEntry {
        SettingsEntry() = default;
 
        SettingsEntry(const std::string &value_) :
                value(value_)
        {}
 
        SettingsEntry(Settings *group_) :
                group(group_),
                is_group(true)
        {}
 
        std::string value = "";
        Settings *group = nullptr;
        bool is_group = false;
};
 
typedef std::unordered_map<std::string, SettingsEntry> SettingEntries;
 
class Settings {
public:
        /* These functions operate on the global hierarchy! */
        static Settings *createLayer(SettingsLayer sl, std::string_view end_tag = "");
        static Settings *getLayer(SettingsLayer sl);
        
 
        Settings(std::string_view end_tag = "") :
                m_end_tag(end_tag)
        {}
        Settings(std::string_view end_tag, SettingsHierarchy *h, int settings_layer);
        ~Settings();
 
        Settings & operator=(const Settings &other);
 
        /***********************
         * Reading and writing *
         ***********************/
 
        // Read configuration file.  Returns success.
        bool readConfigFile(const char *filename);
        //Updates configuration file.  Returns success.
        bool updateConfigFile(const char *filename);
        // NOTE: Types of allowed_options are ignored.  Returns success.
        bool parseCommandLine(int argc, char *argv[],
                        const std::map<std::string, ValueSpec> &allowed_options);
        bool parseConfigLines(std::istream &is);
        void writeLines(std::ostream &os, u32 tab_depth=0) const;
 
        /***********
         * Getters *
         ***********/
 
        Settings *getGroup(const std::string &name) const;
        const std::string &get(const std::string &name) const;
        bool getBool(const std::string &name) const;
        u16 getU16(const std::string &name) const;
        s16 getS16(const std::string &name) const;
        u32 getU32(const std::string &name) const;
        s32 getS32(const std::string &name) const;
        u64 getU64(const std::string &name) const;
        float getFloat(const std::string &name) const;
        float getFloat(const std::string &name, float min, float max) const;
        v2f getV2F(const std::string &name) const;
        v3f getV3F(const std::string &name) const;
        u32 getFlagStr(const std::string &name, const FlagDesc *flagdesc,
                        u32 *flagmask) const;
        bool getNoiseParams(const std::string &name, NoiseParams &np) const;
        bool getNoiseParamsFromValue(const std::string &name, NoiseParams &np) const;
        bool getNoiseParamsFromGroup(const std::string &name, NoiseParams &np) const;
 
        // return all keys used in this object
        std::vector<std::string> getNames() const;
        // check if setting exists anywhere in the hierarchy
        bool exists(const std::string &name) const;
        // check if setting exists in this object ("locally")
        bool existsLocal(const std::string &name) const;
 
 
        /***************************************
         * Getters that don't throw exceptions *
         ***************************************/
 
        bool getGroupNoEx(const std::string &name, Settings *&val) const;
        bool getNoEx(const std::string &name, std::string &val) const;
        bool getFlag(const std::string &name) const;
        bool getU16NoEx(const std::string &name, u16 &val) const;
        bool getS16NoEx(const std::string &name, s16 &val) const;
        bool getU32NoEx(const std::string &name, u32 &val) const;
        bool getS32NoEx(const std::string &name, s32 &val) const;
        bool getU64NoEx(const std::string &name, u64 &val) const;
        bool getFloatNoEx(const std::string &name, float &val) const;
        bool getV2FNoEx(const std::string &name, v2f &val) const;
        bool getV3FNoEx(const std::string &name, v3f &val) const;
 
        // Like other getters, but handling each flag individualy:
        // 1) Read default flags (or 0)
        // 2) Override using user-defined flags
        bool getFlagStrNoEx(const std::string &name, u32 &val,
                const FlagDesc *flagdesc) const;
 
 
        /***********
         * Setters *
         ***********/
 
        // N.B. Groups not allocated with new must be set to NULL in the settings
        // tree before object destruction.
        bool setEntry(const std::string &name, const void *entry,
                bool set_group);
        bool set(const std::string &name, const std::string &value);
        bool setDefault(const std::string &name, const std::string &value);
        bool setGroup(const std::string &name, const Settings &group);
        bool setBool(const std::string &name, bool value);
        bool setS16(const std::string &name, s16 value);
        bool setU16(const std::string &name, u16 value);
        bool setS32(const std::string &name, s32 value);
        bool setU64(const std::string &name, u64 value);
        bool setFloat(const std::string &name, float value);
        bool setV2F(const std::string &name, v2f value);
        bool setV3F(const std::string &name, v3f value);
        bool setFlagStr(const std::string &name, u32 flags,
                const FlagDesc *flagdesc = nullptr, u32 flagmask = U32_MAX);
        bool setNoiseParams(const std::string &name, const NoiseParams &np);
 
        // remove a setting
        bool remove(const std::string &name);
 
        /*****************
         * Miscellaneous *
         *****************/
 
        void setDefault(const std::string &name, const FlagDesc *flagdesc, u32 flags);
        const FlagDesc *getFlagDescFallback(const std::string &name) const;
 
        void registerChangedCallback(const std::string &name,
                SettingsChangedCallback cbf, void *userdata = NULL);
        size_t deregisterAllChangedCallbacks(const void *userdata);
 
        void removeSecureSettings();
 
        // Returns the settings layer this object is.
        // If within the global hierarchy you can cast this to enum SettingsLayer
        inline int getLayer() const { return m_settingslayer; }
 
private:
        /***********************
         * Reading and writing *
         ***********************/
 
        SettingsParseEvent parseConfigObject(const std::string &line,
                std::string &name, std::string &value);
        bool updateConfigObject(std::istream &is, std::ostream &os,
                u32 tab_depth=0);
 
        static bool checkNameValid(std::string_view name);
        static bool checkValueValid(std::string_view value);
        static std::string getMultiline(std::istream &is, size_t *num_lines=NULL);
        static void printEntry(std::ostream &os, const std::string &name,
                const SettingsEntry &entry, u32 tab_depth=0);
 
        /***********
         * Getters *
         ***********/
        Settings *getParent() const;
 
        const SettingsEntry &getEntry(const std::string &name) const;
 
        // Allow TestSettings to run sanity checks using private functions.
        friend class TestSettings;
        // For sane mutex locking when iterating
        friend class LuaSettings;
 
        void clearNoLock();
 
        void doCallbacks(const std::string &name) const;
 
        SettingEntries m_settings;
        SettingsCallbackMap m_callbacks;
        std::string m_end_tag;
 
        mutable std::mutex m_callback_mutex;
 
        // All methods that access m_settings/m_defaults directly should lock this.
        mutable std::mutex m_mutex;
 
        SettingsHierarchy *m_hierarchy = nullptr;
        int m_settingslayer = -1;
 
        static std::unordered_map<std::string, const FlagDesc *> s_flags;
};