Parser context is a wrapper around flex/bison instances dedicated to Control-agent config file parser. More...

#include <parser_context.h>

Public Types
enum	LexerContext { NO_KEYWORDS , CONFIG , AGENT , AUTHENTICATION , AUTH_TYPE , CLIENTS , CONTROL_SOCKETS , SERVER , SOCKET_TYPE , HOOKS_LIBRARIES , LOGGERS , OUTPUT_OPTIONS }
	Defines syntactic contexts for lexical tie-ins. More...

enum	ParserType { PARSER_JSON , PARSER_AGENT , PARSER_SUB_AGENT }
	Defines currently supported scopes. More...

Public Member Functions
	ParserContext ()
	Default constructor.

virtual	~ParserContext ()
	destructor

const std::string	contextName ()
	Get the syntactic context name.

void	enter (const LexerContext &ctx)
	Enter a new syntactic context.

void	error (const isc::agent::location &loc, const std::string &what, size_t pos=0)
	Error handler.

void	error (const std::string &what)
	Error handler.

void	includeFile (const std::string &filename)
	Divert input to an include file.

void	leave ()
	Leave a syntactic context.

isc::data::Element::Position	loc2pos (isc::agent::location &loc)
	Converts bison's position to one understandable by isc::data::Element.

isc::data::ElementPtr	parseFile (const std::string &filename, ParserType parser_type)
	Run the parser on the file specified.

isc::data::ElementPtr	parseString (const std::string &str, ParserType parser_type)
	Run the parser on the string specified.

void	require (const std::string &name, isc::data::Element::Position open_loc, isc::data::Element::Position close_loc)
	Check if a required parameter is present.

void	scanEnd ()
	Method called after the last tokens are scanned.

void	scanFileBegin (FILE *f, const std::string &filename, ParserType type)
	Method called before scanning starts on a file.

void	scanStringBegin (const std::string &str, ParserType type)
	Method called before scanning starts on a string.

void	unique (const std::string &name, isc::data::Element::Position loc)
	Check if a parameter is already present.

void	warnAboutExtraCommas (const isc::agent::location &loc)
	Warning for extra commas.

void	warning (const isc::agent::location &loc, const std::string &what)
	Warning handler.

Static Public Member Functions
static void	fatal (const std::string &what)
	Fatal error handler.

Public Attributes
LexerContext	ctx_
	Current syntactic context.

std::string	file_
	File name.

std::vector< std::string >	files_
	File name stack.

isc::agent::location	loc_
	Location of the current token.

std::vector< isc::agent::location >	locs_
	Location stack.

FILE *	sfile_
	sFile (aka FILE)

std::vector< FILE * >	sfiles_
	sFile (aka FILE) stack

std::vector< isc::data::ElementPtr >	stack_
	JSON elements being parsed.

std::vector< struct yy_buffer_state * >	states_
	Lexer state stack.

Detailed Description

Parser context is a wrapper around flex/bison instances dedicated to Control-agent config file parser.

It follows the same principle as other components. The primary interface are parseString and parseFile methods. All other methods are public for testing purposes only. This interface allows parsing the whole configuration with syntactic checking (which is by far the most frequent use), but it also allows parsing input as generic JSON or parse only content of the Control-agent object, which is a subset of full grammar (this will be very useful for unit-tests to not duplicate unnecessary parts of the config file).

Definition at line 36 of file agent/parser_context.h.

Member Enumeration Documentation

◆ LexerContext

enum isc::agent::ParserContext::LexerContext

Defines syntactic contexts for lexical tie-ins.

Enumerator
NO_KEYWORDS	This one is used in pure JSON mode. Used while parsing top level (that contains Control-agent)
CONFIG	Used while parsing content of Agent.
AGENT	Used while parsing Control-agent/Authentication.
AUTHENTICATION	Used while parsing Control-agent/Authentication/type.
AUTH_TYPE	Used while parsing Control-agent/Authentication/clients.
CLIENTS	Used while parsing Control-agent/control-sockets.
CONTROL_SOCKETS	Used while parsing Control-agent/control-socket/*-server.
SERVER	Used while parsing Control-agent/control-socket/*-server/socket-type.
SOCKET_TYPE	Used while parsing Control-agent/hooks-libraries.
HOOKS_LIBRARIES	Used while parsing Control-agent/loggers structures.
LOGGERS	Used while parsing Control-agent/loggers/output-options structures.
OUTPUT_OPTIONS

Definition at line 196 of file agent/parser_context.h.

◆ ParserType

enum isc::agent::ParserContext::ParserType

Defines currently supported scopes.

AgentParser is able to parse several types of scope. Usually, when it parses a config file, it expects the data to have a map with Control-agent in it and all the parameters within that map. However, sometimes the parser is expected to parse only a subset of that information.

Enumerator
PARSER_JSON	This parser will parse the content as generic JSON.
PARSER_AGENT	This parser will expect the content as Control-agent config wrapped in a map (that's the regular config file)
PARSER_SUB_AGENT	This parser will expect only the content of Control-agent.

Definition at line 47 of file agent/parser_context.h.

Constructor & Destructor Documentation

◆ ParserContext()

isc::agent::ParserContext::ParserContext ( )

Default constructor.

Definition at line 22 of file agent/parser_context.cc.

◆ ~ParserContext()

isc::agent::ParserContext::~ParserContext ( )

virtual

destructor

Definition at line 27 of file agent/parser_context.cc.

Member Function Documentation

◆ contextName()

const std::string isc::agent::ParserContext::contextName ( )

Get the syntactic context name.

Returns: printable name of the context.

Definition at line 157 of file agent/parser_context.cc.

References AGENT, AUTH_TYPE, AUTHENTICATION, CLIENTS, CONFIG, CONTROL_SOCKETS, ctx_, HOOKS_LIBRARIES, LOGGERS, NO_KEYWORDS, OUTPUT_OPTIONS, SERVER, and SOCKET_TYPE.

Referenced by isc::agent::AgentParser::parse(), require(), and unique().

◆ enter()

void isc::agent::ParserContext::enter ( const LexerContext & ctx )

Enter a new syntactic context.

Entering a new syntactic context is useful in several ways. First, it allows the parser to avoid conflicts. Second, it allows the lexer to return different tokens depending on context (e.g. if "renew-timer" string is detected, the lexer will return STRING token if in JSON mode or RENEW_TIMER if in DHCP6 mode. Finally, the syntactic context allows the error message to be more descriptive if the input string does not parse properly. Control Agent parser uses simplified contexts: either it recognizes keywords (value set to KEYWORDS) or not (value set to NO_KEYWORDS).

Make sure to call leave() once the parsing of your context is complete.

Parameters

ctx	the syntactic context to enter into

Definition at line 140 of file agent/parser_context.cc.

References ctx_.

Referenced by isc::agent::AgentParser::parse().

◆ error() [1/2]

void isc::agent::ParserContext::error	(	const isc::agent::location &	loc,
		const std::string &	what,
		size_t	pos = `0`
	)

Error handler.

Note: The optional position for an error in a string begins by 1 so the caller should add 1 to the position of the C++ string.

Parameters

loc	location within the parsed file where the problem was experienced.
what	string explaining the nature of the error.
pos	optional position for in string errors.

Exceptions

ParseError

Definition at line 74 of file agent/parser_context.cc.

References isc_throw.

◆ error() [2/2]

void isc::agent::ParserContext::error ( const std::string & what )

Error handler.

This is a simplified error reporting tool for possible future cases when the AgentParser is not able to handle the packet.

Parameters

what	string explaining the nature of the error.

Exceptions

ParseError

Definition at line 86 of file agent/parser_context.cc.

References isc_throw.

◆ fatal()

void isc::agent::ParserContext::fatal ( const std::string & what )

static

Fatal error handler.

This is for should not happen but fatal errors. Used by YY_FATAL_ERROR macro so required to be static.

Parameters

what	string explaining the nature of the error.

Exceptions

ParseError

Definition at line 92 of file agent/parser_context.cc.

References isc_throw.

Referenced by leave().

◆ includeFile()

void ParserContext::includeFile ( const std::string & filename )

Divert input to an include file.

Parameters

filename file to be included

Definition at line 4112 of file agent_lexer.cc.

References BEGIN, isc::db::fatal, file_, files_, INITIAL, loc_, locs_, sfile_, sfiles_, states_, and YY_CURRENT_BUFFER.

◆ leave()

void isc::agent::ParserContext::leave ( )

Leave a syntactic context.

enter() must be called before (when entering a new scope or context). Once you complete the parsing, this method should be called.

Exceptions

isc::Unexpected if unbalanced (more leave() than enter() calls)

Definition at line 147 of file agent/parser_context.cc.

References ctx_, and fatal().

Referenced by isc::agent::AgentParser::parse().

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◆ loc2pos()

isc::data::Element::Position isc::agent::ParserContext::loc2pos ( isc::agent::location & loc )

Converts bison's position to one understandable by isc::data::Element.

Convert a bison location into an element position (take the begin, the end is lost)

Parameters

loc	location in bison format

Returns: Position in format accepted by Element

Definition at line 98 of file agent/parser_context.cc.

Referenced by isc::agent::AgentParser::parse().

◆ parseFile()

isc::data::ElementPtr isc::agent::ParserContext::parseFile	(	const std::string &	filename,
		ParserType	parser_type
	)

Run the parser on the file specified.

This method parses specified file. Depending on the value of parser_type, parser may either check only that the input is valid JSON, or may do more specific syntax checking. See ParserType for supported syntax checkers.

Parameters

filename	file to be parsed
parser_type	specifies expected content (usually PARSER_AGENT or PARSER_JSON)

Returns: Element structure representing parsed text.

Definition at line 39 of file agent/parser_context.cc.

References isc_throw, and scanFileBegin().

Referenced by isc::agent::CtrlAgentController::parseFile().

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◆ parseString()

isc::data::ElementPtr isc::agent::ParserContext::parseString	(	const std::string &	str,
		ParserType	parser_type
	)

Run the parser on the string specified.

This method parses specified string. Depending on the value of parser_type, parser may either check only that the input is valid JSON, or may do more specific syntax checking. See ParserType for supported syntax checkers.

Parameters