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#include <map>
#include <set>
#include "libutil/types.hh"
#pragma once
namespace nix {
class Args;
class AbstractSetting;
class JSONPlaceholder;
class JSONObject;
class AbstractConfig {
protected:
StringMap unknownSettings;
explicit AbstractConfig(const StringMap& initials = {})
: unknownSettings(initials) {}
public:
virtual bool set(const std::string& name, const std::string& value) = 0;
struct SettingInfo {
std::string value;
std::string description;
};
virtual void getSettings(std::map<std::string, SettingInfo>& res,
bool overridenOnly = false) = 0;
void applyConfigFile(const Path& path);
virtual void resetOverriden() = 0;
virtual void toJSON(JSONObject& out) = 0;
virtual void convertToArgs(Args& args, const std::string& category) = 0;
void warnUnknownSettings();
void reapplyUnknownSettings();
};
/* A class to simplify providing configuration settings. The typical
use is to inherit Config and add Setting<T> members:
class MyClass : private Config
{
Setting<int> foo{this, 123, "foo", "the number of foos to use"};
Setting<std::string> bar{this, "blabla", "bar", "the name of the bar"};
MyClass() : Config(readConfigFile("/etc/my-app.conf"))
{
std::cout << foo << "\n"; // will print 123 unless overriden
}
};
*/
class Config : public AbstractConfig {
friend class AbstractSetting;
public:
struct SettingData {
bool isAlias;
AbstractSetting* setting;
SettingData(bool isAlias, AbstractSetting* setting)
: isAlias(isAlias), setting(setting) {}
};
typedef std::map<std::string, SettingData> Settings;
private:
Settings _settings;
public:
explicit Config(const StringMap& initials = {}) : AbstractConfig(initials) {}
bool set(const std::string& name, const std::string& value) override;
void addSetting(AbstractSetting* setting);
void getSettings(std::map<std::string, SettingInfo>& res,
bool overridenOnly = false) override;
void resetOverriden() override;
void toJSON(JSONObject& out) override;
void convertToArgs(Args& args, const std::string& category) override;
};
class AbstractSetting {
friend class Config;
public:
const std::string name;
const std::string description;
const std::set<std::string> aliases;
int created = 123;
bool overriden = false;
protected:
AbstractSetting(std::string name, std::string description,
std::set<std::string> aliases);
virtual ~AbstractSetting() {
// Check against a gcc miscompilation causing our constructor
// not to run (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80431).
assert(created == 123);
}
virtual void set(const std::string& value) = 0;
virtual std::string to_string() = 0;
virtual void toJSON(JSONPlaceholder& out);
virtual void convertToArg(Args& args, const std::string& category);
bool isOverriden() { return overriden; }
};
/* A setting of type T. */
template <typename T>
class BaseSetting : public AbstractSetting {
protected:
T value;
public:
BaseSetting(const T& def, const std::string& name,
const std::string& description,
const std::set<std::string>& aliases = {})
: AbstractSetting(name, description, aliases), value(def) {}
operator const T&() const { return value; }
operator T&() { return value; }
const T& get() const { return value; }
bool operator==(const T& v2) const { return value == v2; }
bool operator!=(const T& v2) const { return value != v2; }
void operator=(const T& v) { assign(v); }
virtual void assign(const T& v) { value = v; }
void set(const std::string& str) override;
virtual void override(const T& v) {
overriden = true;
value = v;
}
std::string to_string() override;
void convertToArg(Args& args, const std::string& category) override;
void toJSON(JSONPlaceholder& out) override;
};
template <typename T>
std::ostream& operator<<(std::ostream& str, const BaseSetting<T>& opt) {
str << (const T&)opt;
return str;
}
template <typename T>
bool operator==(const T& v1, const BaseSetting<T>& v2) {
return v1 == (const T&)v2;
}
template <typename T>
class Setting : public BaseSetting<T> {
public:
Setting(Config* options, const T& def, const std::string& name,
const std::string& description,
const std::set<std::string>& aliases = {})
: BaseSetting<T>(def, name, description, aliases) {
options->addSetting(this);
}
void operator=(const T& v) { this->assign(v); }
};
/* A special setting for Paths. These are automatically canonicalised
(e.g. "/foo//bar/" becomes "/foo/bar"). */
class PathSetting : public BaseSetting<Path> {
bool allowEmpty;
public:
PathSetting(Config* options, bool allowEmpty, const Path& def,
const std::string& name, const std::string& description,
const std::set<std::string>& aliases = {})
: BaseSetting<Path>(def, name, description, aliases),
allowEmpty(allowEmpty) {
options->addSetting(this);
}
void set(const std::string& str) override;
Path operator+(const char* p) const { return value + p; }
void operator=(const Path& v) { this->assign(v); }
};
struct GlobalConfig : public AbstractConfig {
using ConfigRegistrations = std::vector<Config*>;
static ConfigRegistrations* configRegistrations;
bool set(const std::string& name, const std::string& value) override;
void getSettings(std::map<std::string, SettingInfo>& res,
bool overridenOnly = false) override;
void resetOverriden() override;
void toJSON(JSONObject& out) override;
void convertToArgs(Args& args, const std::string& category) override;
struct Register {
explicit Register(Config* config);
};
};
extern GlobalConfig globalConfig;
} // namespace nix
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