Current File : //backups/router/usr/local/include/kea/eval/eval_context.h
// Copyright (C) 2015-2022 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef EVAL_CONTEXT_H
#define EVAL_CONTEXT_H
#include <string>
#include <map>
#include <eval/parser.h>
#include <eval/eval_context_decl.h>
#include <exceptions/exceptions.h>
// Tell Flex the lexer's prototype ...
#define YY_DECL \
isc::eval::EvalParser::symbol_type evallex (EvalContext& driver)
// ... and declare it for the parser's sake.
YY_DECL;
namespace isc {
namespace eval {
/// @brief Evaluation error exception raised when trying to parse an exceptions.
class EvalParseError : public isc::Exception {
public:
EvalParseError(const char* file, size_t line, const char* what) :
isc::Exception(file, line, what) { };
};
/// @brief Evaluation context, an interface to the expression evaluation.
class EvalContext {
public:
/// @brief Specifies what type of expression the parser is expected to see
typedef enum {
PARSER_BOOL, ///< expression is expected to evaluate to bool
PARSER_STRING ///< expression is expected to evaluate to string
} ParserType;
/// @brief Type of the check defined function.
typedef std::function<bool(const ClientClass&)> CheckDefined;
/// @brief Default constructor.
///
/// @param option_universe Option universe: DHCPv4 or DHCPv6. This is used
/// by the parser to determine which option definitions set should be used
/// to map option names to option codes.
/// @param check_defined A function called to check if a client class
/// used for membership is already defined. If it is not the parser
/// will fail: only backward or built-in references are accepted.
EvalContext(const Option::Universe& option_universe,
CheckDefined check_defined = acceptAll);
/// @brief destructor
virtual ~EvalContext();
/// @brief Accept all client class names
///
/// @param client_class (unused)
/// @return true
static bool acceptAll(const ClientClass& client_class);
/// @brief Parsed expression (output tokens are stored here)
isc::dhcp::Expression expression;
/// @brief Method called before scanning starts on a string.
///
/// @param type specifies type of the expression to be parsed
void scanStringBegin(ParserType type);
/// @brief Method called after the last tokens are scanned from a string.
void scanStringEnd();
/// @brief Run the parser on the string specified.
///
/// @param str string to be parsed
/// @param type type of the expression expected/parser type to be created
/// @return true on success.
bool parseString(const std::string& str, ParserType type = PARSER_BOOL);
/// @brief The name of the file being parsed.
/// Used later to pass the file name to the location tracker.
std::string file_;
/// @brief The string being parsed.
std::string string_;
/// @brief Error handler
///
/// @param loc location within the parsed file where the problem was experienced.
/// @param what string explaining the nature of the error.
static void error(const isc::eval::location& loc, const std::string& what);
/// @brief Error handler
///
/// This is a simplified error reporting tool for possible future
/// cases when the EvalParser is not able to handle the packet.
static void error(const std::string& what);
/// @brief Fatal error handler
///
/// This is for should not happen but fatal errors
static void fatal(const std::string& what);
/// @brief Option code conversion
///
/// @param option_code a string representing the integer code
/// @param loc the location of the token
/// @result the option code
/// @throw calls the syntax error function if the value is not in
/// the range 0..255 or 0..65535
uint16_t convertOptionCode(const std::string& option_code,
const isc::eval::location& loc);
/// @brief Option name conversion
///
/// @param option_name the option name
/// @param loc the location of the token
/// @return the option code
/// @throw calls the syntax error function if the name cannot be resolved
uint16_t convertOptionName(const std::string& option_name,
const isc::eval::location& loc);
/// @brief Attempts to convert string to unsigned 32bit integer
///
/// For reverse conversion, see @ref fromUint32
///
/// @param number string to be converted
/// @param loc the location of the token
/// @return the integer value
/// @throw EvalParseError if conversion fails or the value is out of range.
static uint32_t convertUint32(const std::string& number,
const isc::eval::location& loc);
/// @brief Attempts to convert string to signed 32bit integer
///
/// @param number string to be converted
/// @param loc the location of the token
/// @return the integer value
/// @throw EvalParseError if conversion fails or the value is out of range.
static int32_t convertInt32(const std::string& number,
const isc::eval::location& loc);
/// @brief Attempts to convert string to unsigned 16bit integer
///
/// For reverse conversion, see @ref fromUint16
///
/// @param number string to be converted
/// @param loc the location of the token
/// @return the integer value
/// @throw EvalParseError if conversion fails or the value is out of range.
static uint16_t convertUint16(const std::string& number,
const isc::eval::location& loc);
/// @brief Attempts to convert string to signed 16bit integer
///
/// @param number string to be converted
/// @param loc the location of the token
/// @return the integer value
/// @throw EvalParseError if conversion fails or the value is out of range.
static int16_t convertInt16(const std::string& number,
const isc::eval::location& loc);
/// @brief Attempts to convert string to unsigned 8bit integer
///
/// @param number string to be converted
/// @param loc the location of the token
/// @return the integer value
/// @throw EvalParseError if conversion fails or the value is out of range.
static uint8_t convertUint8(const std::string& number,
const isc::eval::location& loc);
/// @brief Attempts to convert string to signed 8bit integer
///
/// @param number string to be converted
/// @param loc the location of the token
/// @return the integer value
/// @throw EvalParseError if conversion fails or the value is out of range.
static int8_t convertInt8(const std::string& number,
const isc::eval::location& loc);
/// @brief Nest level conversion
///
/// @param nest_level a string representing the integer nesting level
/// @param loc the location of the token
/// @return the nesting level
/// @throw calls the syntax error function if the value is not in
/// the range -32..31
int8_t convertNestLevelNumber(const std::string& nest_level,
const isc::eval::location& loc);
/// @brief Converts unsigned 32bit integer to string representation
///
/// The integer is coded as a 4 byte long string in network order, e.g.
/// 6 is represented as 00000006. For reverse conversion, see
/// @ref convertUint32.
///
/// @param integer value to be converted
/// @return 4 byte long string that encodes the value.
static std::string fromUint32(const uint32_t integer);
/// @brief Converts unsigned 16bit integer to string representation
///
/// The integer is coded as a 2 byte long string in network order, e.g.
/// 6 is represented as 0006. For reverse conversion, see
/// @ref convertUint16.
///
/// @param integer value to be converted
/// @return 2 byte long string that encodes the value.
static std::string fromUint16(const uint16_t integer);
/// @brief Returns the universe (v4 or v6)
///
/// @return universe
Option::Universe getUniverse() {
return (option_universe_);
}
/// @brief Check if a client class is already defined
///
/// @param client_class the client class name to check
/// @return true if the client class is defined, false if not
bool isClientClassDefined(const ClientClass& client_class);
private:
/// @brief Flag determining scanner debugging.
bool trace_scanning_;
/// @brief Flag determining parser debugging.
bool trace_parsing_;
/// @brief Option universe: DHCPv4 or DHCPv6.
///
/// This is used by the parser to determine which option definitions
/// set should be used to map option name to option code.
Option::Universe option_universe_;
/// @brief Function to check if a client class is already defined.
CheckDefined check_defined_;
};
} // end of isc::eval namespace
} // end of isc namespace
#endif
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