Kea  2.3.4-git
isc::agent::ParserContext Class Reference

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. More...
 
virtual ~ParserContext ()
 destructor More...
 
const std::string contextName ()
 Get the syntactic context name. More...
 
void enter (const LexerContext &ctx)
 Enter a new syntactic context. More...
 
void error (const isc::agent::location &loc, const std::string &what, size_t pos=0)
 Error handler. More...
 
void error (const std::string &what)
 Error handler. More...
 
void includeFile (const std::string &filename)
 Divert input to an include file. More...
 
void leave ()
 Leave a syntactic context. More...
 
isc::data::Element::Position loc2pos (isc::agent::location &loc)
 Converts bison's position to one understandable by isc::data::Element. More...
 
isc::data::ElementPtr parseFile (const std::string &filename, ParserType parser_type)
 Run the parser on the file specified. More...
 
isc::data::ElementPtr parseString (const std::string &str, ParserType parser_type)
 Run the parser on the string specified. More...
 
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. More...
 
void scanEnd ()
 Method called after the last tokens are scanned. More...
 
void scanFileBegin (FILE *f, const std::string &filename, ParserType type)
 Method called before scanning starts on a file. More...
 
void scanStringBegin (const std::string &str, ParserType type)
 Method called before scanning starts on a string. More...
 
void unique (const std::string &name, isc::data::Element::Position loc)
 Check if a parameter is already present. More...
 
void warnAboutExtraCommas (const isc::agent::location &loc)
 Warning for extra commas. More...
 
void warning (const isc::agent::location &loc, const std::string &what)
 Warning handler. More...
 

Static Public Member Functions

static void fatal (const std::string &what)
 Fatal error handler. More...
 

Public Attributes

LexerContext ctx_
 Current syntactic context. More...
 
std::string file_
 File name. More...
 
std::vector< std::string > files_
 File name stack. More...
 
isc::agent::location loc_
 Location of the current token. More...
 
std::vector< isc::agent::location > locs_
 Location stack. More...
 
FILE * sfile_
 sFile (aka FILE) More...
 
std::vector< FILE * > sfiles_
 sFile (aka FILE) stack More...
 
std::vector< isc::data::ElementPtrstack_
 JSON elements being parsed. More...
 
std::vector< struct yy_buffer_state * > states_
 Lexer state stack. More...
 

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

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

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
ctxthe 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
loclocation within the parsed file where the problem was experienced.
whatstring explaining the nature of the error.
posoptional 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
whatstring 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
whatstring 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
filenamefile to be included

Definition at line 4076 of file agent_lexer.cc.

References BEGIN, isc::db::fatal, INITIAL, 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::Unexpectedif 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
loclocation 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
filenamefile to be parsed
parser_typespecifies 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, isc::agent::AgentParser::parse(), scanEnd(), scanFileBegin(), isc::agent::AgentParser::set_debug_level(), and stack_.

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
strstring to be parsed
parser_typespecifies expected content (usually AGENT or generic JSON)
Returns
Element structure representing parsed text.

Definition at line 32 of file agent/parser_context.cc.

References scanStringBegin().

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◆ require()

void isc::agent::ParserContext::require ( const std::string &  name,
isc::data::Element::Position  open_loc,
isc::data::Element::Position  close_loc 
)

Check if a required parameter is present.

Check if a required parameter is present in the map at the top of the stack and raise an error when it is not.

Parameters
namename of the parameter to check
open_loclocation of the opening curly bracket
close_loclocation of the closing curly bracket
Exceptions
ParseError

Definition at line 107 of file agent/parser_context.cc.

References contextName(), isc_throw, and stack_.

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

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◆ scanEnd()

void ParserContext::scanEnd ( )

Method called after the last tokens are scanned.

Definition at line 4055 of file agent_lexer.cc.

Referenced by parseFile().

◆ scanFileBegin()

void ParserContext::scanFileBegin ( FILE *  f,
const std::string &  filename,
ParserType  type 
)

Method called before scanning starts on a file.

Parameters
fstdio FILE pointer
filenamefile to be parsed
typespecifies expected content

Definition at line 4033 of file agent_lexer.cc.

References isc::db::fatal, and yy_flex_debug.

Referenced by parseFile().

◆ scanStringBegin()

void ParserContext::scanStringBegin ( const std::string &  str,
ParserType  type 
)

Method called before scanning starts on a string.

Parameters
strstring to be parsed
typespecifies expected content

Definition at line 4015 of file agent_lexer.cc.

References isc::db::fatal, and yy_flex_debug.

Referenced by parseString().

◆ unique()

void isc::agent::ParserContext::unique ( const std::string &  name,
isc::data::Element::Position  loc 
)

Check if a parameter is already present.

Check if a parameter is already present in the map at the top of the stack and raise an error when it is.

Parameters
namename of the parameter to check
loclocation of the current parameter
Exceptions
ParseError

Definition at line 122 of file agent/parser_context.cc.

References contextName(), ctx_, isc_throw, NO_KEYWORDS, and stack_.

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

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◆ warnAboutExtraCommas()

void isc::agent::ParserContext::warnAboutExtraCommas ( const isc::agent::location &  loc)

Warning for extra commas.

Parameters
loclocation within the parsed file of the extra comma
Exceptions
ParseError

Definition at line 199 of file agent/parser_context.cc.

References warning().

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

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◆ warning()

void isc::agent::ParserContext::warning ( const isc::agent::location &  loc,
const std::string &  what 
)

Warning handler.

Parameters
loclocation within the parsed file where the problem was experienced
whatstring explaining the nature of the error
Exceptions
ParseError

Definition at line 190 of file agent/parser_context.cc.

References isc::agent::agent_logger, isc::agent::CTRL_AGENT_CONFIG_SYNTAX_WARNING, and LOG_WARN.

Referenced by warnAboutExtraCommas().

Member Data Documentation

◆ ctx_

LexerContext isc::agent::ParserContext::ctx_

Current syntactic context.

Definition at line 263 of file agent/parser_context.h.

Referenced by contextName(), enter(), leave(), isc::agent::AgentParser::parse(), and unique().

◆ file_

std::string isc::agent::ParserContext::file_

File name.

Definition at line 235 of file agent/parser_context.h.

◆ files_

std::vector<std::string> isc::agent::ParserContext::files_

File name stack.

Definition at line 238 of file agent/parser_context.h.

◆ loc_

isc::agent::location isc::agent::ParserContext::loc_

Location of the current token.

The lexer will keep updating it. This variable will be useful for logging errors.

Definition at line 244 of file agent/parser_context.h.

◆ locs_

std::vector<isc::agent::location> isc::agent::ParserContext::locs_

Location stack.

Definition at line 247 of file agent/parser_context.h.

◆ sfile_

FILE* isc::agent::ParserContext::sfile_

sFile (aka FILE)

Definition at line 253 of file agent/parser_context.h.

◆ sfiles_

std::vector<FILE*> isc::agent::ParserContext::sfiles_

sFile (aka FILE) stack

This is a stack of files. Typically there's only one file (the one being currently parsed), but there may be more if one file includes another.

Definition at line 260 of file agent/parser_context.h.

◆ stack_

std::vector<isc::data::ElementPtr> isc::agent::ParserContext::stack_

JSON elements being parsed.

Definition at line 66 of file agent/parser_context.h.

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

◆ states_

std::vector<struct yy_buffer_state*> isc::agent::ParserContext::states_

Lexer state stack.

Definition at line 250 of file agent/parser_context.h.


The documentation for this class was generated from the following files: