SettingsConstraints.cpp

#include <Access/SettingsConstraints.h>
#include <Access/AccessControl.h>
#include <Core/Settings.h>
#include <Common/FieldVisitorToString.h>
#include <Common/FieldVisitorsAccurateComparison.h>
#include <IO/WriteHelpers.h>
#include <Poco/Util/AbstractConfiguration.h>
#include <boost/range/algorithm_ext/erase.hpp>


namespace DB
{
namespace ErrorCodes
{
    extern const int READONLY;
    extern const int QUERY_IS_PROHIBITED;
    extern const int SETTING_CONSTRAINT_VIOLATION;
    extern const int UNKNOWN_SETTING;
}


SettingsConstraints::SettingsConstraints(const AccessControl & access_control_) : access_control(&access_control_)
{
}

SettingsConstraints::SettingsConstraints(const SettingsConstraints & src) = default;
SettingsConstraints & SettingsConstraints::operator=(const SettingsConstraints & src) = default;
SettingsConstraints::SettingsConstraints(SettingsConstraints && src) noexcept = default;
SettingsConstraints & SettingsConstraints::operator=(SettingsConstraints && src) noexcept = default;
SettingsConstraints::~SettingsConstraints() = default;


void SettingsConstraints::clear()
{
    constraints.clear();
}


void SettingsConstraints::setMinValue(std::string_view setting_name, const Field & min_value)
{
    getConstraintRef(setting_name).min_value = Settings::castValueUtil(setting_name, min_value);
}

Field SettingsConstraints::getMinValue(std::string_view setting_name) const
{
    const auto * ptr = tryGetConstraint(setting_name);
    if (ptr)
        return ptr->min_value;
    else
        return {};
}


void SettingsConstraints::setMaxValue(std::string_view setting_name, const Field & max_value)
{
    getConstraintRef(setting_name).max_value = Settings::castValueUtil(setting_name, max_value);
}

Field SettingsConstraints::getMaxValue(std::string_view setting_name) const
{
    const auto * ptr = tryGetConstraint(setting_name);
    if (ptr)
        return ptr->max_value;
    else
        return {};
}


void SettingsConstraints::setReadOnly(std::string_view setting_name, bool read_only)
{
    getConstraintRef(setting_name).read_only = read_only;
}

bool SettingsConstraints::isReadOnly(std::string_view setting_name) const
{
    const auto * ptr = tryGetConstraint(setting_name);
    if (ptr)
        return ptr->read_only;
    else
        return false;
}


void SettingsConstraints::set(std::string_view setting_name, const Field & min_value, const Field & max_value, bool read_only)
{
    auto & ref = getConstraintRef(setting_name);
    ref.min_value = Settings::castValueUtil(setting_name, min_value);
    ref.max_value = Settings::castValueUtil(setting_name, max_value);
    ref.read_only = read_only;
}

void SettingsConstraints::get(std::string_view setting_name, Field & min_value, Field & max_value, bool & read_only) const
{
    const auto * ptr = tryGetConstraint(setting_name);
    if (ptr)
    {
        min_value = ptr->min_value;
        max_value = ptr->max_value;
        read_only = ptr->read_only;
    }
    else
    {
        min_value = Field{};
        max_value = Field{};
        read_only = false;
    }
}

void SettingsConstraints::merge(const SettingsConstraints & other)
{
    for (const auto & [other_name, other_constraint] : other.constraints)
    {
        auto & constraint = getConstraintRef(other_name);
        if (!other_constraint.min_value.isNull())
            constraint.min_value = other_constraint.min_value;
        if (!other_constraint.max_value.isNull())
            constraint.max_value = other_constraint.max_value;
        if (other_constraint.read_only)
            constraint.read_only = true;
    }
}


void SettingsConstraints::check(const Settings & current_settings, const SettingChange & change) const
{
    checkImpl(current_settings, const_cast<SettingChange &>(change), THROW_ON_VIOLATION);
}

void SettingsConstraints::check(const Settings & current_settings, const SettingsChanges & changes) const
{
    for (const auto & change : changes)
        check(current_settings, change);
}

void SettingsConstraints::check(const Settings & current_settings, SettingsChanges & changes) const
{
    boost::range::remove_erase_if(
        changes,
        [&](SettingChange & change) -> bool
        {
            return !checkImpl(current_settings, const_cast<SettingChange &>(change), THROW_ON_VIOLATION);
        });
}

void SettingsConstraints::clamp(const Settings & current_settings, SettingsChanges & changes) const
{
    boost::range::remove_erase_if(
        changes,
        [&](SettingChange & change) -> bool
        {
            return !checkImpl(current_settings, change, CLAMP_ON_VIOLATION);
        });
}


bool SettingsConstraints::checkImpl(const Settings & current_settings, SettingChange & change, ReactionOnViolation reaction) const
{
    const String & setting_name = change.name;

    if (setting_name == "profile")
        return true;

    bool cannot_cast;
    auto cast_value = [&](const Field & x) -> Field
    {
        cannot_cast = false;
        if (reaction == THROW_ON_VIOLATION)
            return Settings::castValueUtil(setting_name, x);
        else
        {
            try
            {
                return Settings::castValueUtil(setting_name, x);
            }
            catch (...)
            {
                cannot_cast = true;
                return {};
            }
        }
    };

    bool cannot_compare = false;
    auto less = [&](const Field & left, const Field & right)
    {
        cannot_compare = false;
        if (reaction == THROW_ON_VIOLATION)
            return applyVisitor(FieldVisitorAccurateLess{}, left, right);
        else
        {
            try
            {
                return applyVisitor(FieldVisitorAccurateLess{}, left, right);
            }
            catch (...)
            {
                cannot_compare = true;
                return false;
            }
        }
    };

    if (reaction == THROW_ON_VIOLATION)
    {
        try
        {
            access_control->checkSettingNameIsAllowed(setting_name);
        }
        catch (Exception & e)
        {
            if (e.code() == ErrorCodes::UNKNOWN_SETTING)
            {
                if (const auto hints = current_settings.getHints(change.name); !hints.empty())
                {
                      e.addMessage(fmt::format("Maybe you meant {}", toString(hints)));
                }
            }
            throw;
        }
    }
    else if (!access_control->isSettingNameAllowed(setting_name))
        return false;

    Field current_value, new_value;
    if (current_settings.tryGet(setting_name, current_value))
    {
        /// Setting isn't checked if value has not changed.
        if (change.value == current_value)
            return false;

        new_value = cast_value(change.value);
        if ((new_value == current_value) || cannot_cast)
            return false;
    }
    else
    {
        new_value = cast_value(change.value);
        if (cannot_cast)
            return false;
    }

    if (!current_settings.allow_ddl && setting_name == "allow_ddl")
    {
        if (reaction == THROW_ON_VIOLATION)
            throw Exception("Cannot modify 'allow_ddl' setting when DDL queries are prohibited for the user", ErrorCodes::QUERY_IS_PROHIBITED);
        else
            return false;
    }

    /** The `readonly` value is understood as follows:
      * 0 - everything allowed.
      * 1 - only read queries can be made; you can not change the settings.
      * 2 - You can only do read queries and you can change the settings, except for the `readonly` setting.
      */
    if (current_settings.readonly == 1)
    {
        if (reaction == THROW_ON_VIOLATION)
            throw Exception("Cannot modify '" + setting_name + "' setting in readonly mode", ErrorCodes::READONLY);
        else
            return false;
    }

    if (current_settings.readonly > 1 && setting_name == "readonly")
    {
        if (reaction == THROW_ON_VIOLATION)
            throw Exception("Cannot modify 'readonly' setting in readonly mode", ErrorCodes::READONLY);
        else
            return false;
    }

    const Constraint * constraint = tryGetConstraint(setting_name);
    if (constraint)
    {
        if (constraint->read_only)
        {
            if (reaction == THROW_ON_VIOLATION)
                throw Exception("Setting " + setting_name + " should not be changed", ErrorCodes::SETTING_CONSTRAINT_VIOLATION);
            else
                return false;
        }

        const Field & min_value = constraint->min_value;
        const Field & max_value = constraint->max_value;
        if (!min_value.isNull() && !max_value.isNull() && (less(max_value, min_value) || cannot_compare))
        {
            if (reaction == THROW_ON_VIOLATION)
                throw Exception("Setting " + setting_name + " should not be changed", ErrorCodes::SETTING_CONSTRAINT_VIOLATION);
            else
                return false;
        }

        if (!min_value.isNull() && (less(new_value, min_value) || cannot_compare))
        {
            if (reaction == THROW_ON_VIOLATION)
            {
                throw Exception(
                    "Setting " + setting_name + " shouldn't be less than " + applyVisitor(FieldVisitorToString(), constraint->min_value),
                    ErrorCodes::SETTING_CONSTRAINT_VIOLATION);
            }
            else
                change.value = min_value;
        }

        if (!max_value.isNull() && (less(max_value, new_value) || cannot_compare))
        {
            if (reaction == THROW_ON_VIOLATION)
            {
                throw Exception(
                    "Setting " + setting_name + " shouldn't be greater than " + applyVisitor(FieldVisitorToString(), constraint->max_value),
                    ErrorCodes::SETTING_CONSTRAINT_VIOLATION);
            }
            else
                change.value = max_value;
        }
    }

    return true;
}


SettingsConstraints::Constraint & SettingsConstraints::getConstraintRef(std::string_view setting_name)
{
    auto it = constraints.find(setting_name);
    if (it == constraints.end())
    {
        auto setting_name_ptr = std::make_shared<const String>(setting_name);
        Constraint new_constraint;
        new_constraint.setting_name = setting_name_ptr;
        it = constraints.emplace(*setting_name_ptr, std::move(new_constraint)).first;
    }
    return it->second;
}

const SettingsConstraints::Constraint * SettingsConstraints::tryGetConstraint(std::string_view setting_name) const
{
    auto it = constraints.find(setting_name);
    if (it == constraints.end())
        return nullptr;
    return &it->second;
}


bool SettingsConstraints::Constraint::operator==(const Constraint & other) const
{
    return (read_only == other.read_only) && (min_value == other.min_value) && (max_value == other.max_value)
        && (*setting_name == *other.setting_name);
}

bool operator ==(const SettingsConstraints & left, const SettingsConstraints & right)
{
    return (left.constraints == right.constraints);
}
}