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G::MapFile Class Reference

A class for reading, writing and editing key=value files, supporting variable expansion of percent-key-percent values, comments, creation of backup files, and logging. More...

#include <gmapfile.h>

Classes

struct  Error
 Exception class for G::MapFile. More...
 

Public Member Functions

 MapFile ()
 Constructor for an empty map.
 
 MapFile (const G::StringMap &map)
 Constructor that initialises from a string map. More...
 
 MapFile (const OptionMap &map, const std::string &yes=std::string())
 Constructor that initialises from an option value map, typically parsed out from a command-line. More...
 
 MapFile (const G::Path &, const std::string &kind=std::string())
 Constructor that reads from a file. More...
 
 MapFile (std::istream &)
 Constructor that reads from a stream. More...
 
const G::StringArraykeys () const
 Returns a reference to the internal ordered list of keys. More...
 
void add (const std::string &key, const std::string &value, bool clear=false)
 Adds or updates a single item in the map. More...
 
void writeItem (std::ostream &, const std::string &key) const
 Writes a single item from this map to the stream. More...
 
void editInto (const G::Path &path, bool make_backup, bool allow_read_error, bool allow_write_error) const
 Edits an existing file so that its contents reflect this map. More...
 
bool contains (const std::string &key) const
 Returns true if the map contains the given key. More...
 
G::Path pathValue (const std::string &key) const
 Returns a mandatory path value from the map. More...
 
G::Path pathValue (const std::string &key, const G::Path &default_) const
 Returns a path value from the map. More...
 
unsigned int numericValue (const std::string &key, unsigned int default_) const
 Returns a numeric value from the map. More...
 
std::string value (const std::string &key, const std::string &default_=std::string()) const
 Returns a string value from the map. More...
 
std::string value (const std::string &key, const char *default_) const
 Returns a string value from the map. More...
 
bool booleanValue (const std::string &key, bool default_) const
 Returns a boolean value from the map. More...
 
void remove (const std::string &key)
 Removes a value (if it exists). More...
 
const G::StringMapmap () const
 Returns a reference to the internal map. More...
 
void log (const std::string &prefix=std::string()) const
 Logs the contents. More...
 
std::string expand (const std::string &value) const
 Does one-pass variable substitution for the given string. More...
 
G::Path expandedPathValue (const std::string &key) const
 Returns a mandatory path value from the map with expand(). More...
 
G::Path expandedPathValue (const std::string &key, const G::Path &default_) const
 Returns a path value from the map with expand(). More...
 

Static Public Member Functions

static void check (const G::Path &, const std::string &kind=std::string())
 Throws if the file is invalid. More...
 
static void writeItem (std::ostream &, const std::string &key, const std::string &value)
 Writes an arbitrary item to the stream. More...
 

Detailed Description

A class for reading, writing and editing key=value files, supporting variable expansion of percent-key-percent values, comments, creation of backup files, and logging.

Also supports initialisation from a G::OptionMap, containing G::OptionValue values. See also G::OptionParser.

Values containing whitespace are/can-be simply quoted with initial and terminal double-quote characters, but with no special handling of escapes or embedded quotes. For full transparency values must not start with whitespace or '=', must not end with whitespace, must not start-and-end with double-quotes, must not contain commas, and should not contain percent characters if using expand() methods.

Definition at line 56 of file gmapfile.h.

Constructor & Destructor Documentation

◆ MapFile() [1/4]

G::MapFile::MapFile ( const G::StringMap map)
explicit

Constructor that initialises from a string map.

Definition at line 55 of file gmapfile.cpp.

◆ MapFile() [2/4]

G::MapFile::MapFile ( const OptionMap map,
const std::string &  yes = std::string() 
)
explicit

Constructor that initialises from an option value map, typically parsed out from a command-line.

Unvalued 'on' options in the option value map are loaded into this mapfile object with a value given by the 'yes' parameter, whereas unvalued 'off' options are not loaded at all. Multi-valued options are loaded as a comma-separated list.

Definition at line 63 of file gmapfile.cpp.

◆ MapFile() [3/4]

G::MapFile::MapFile ( const G::Path path,
const std::string &  kind = std::string() 
)
explicit

Constructor that reads from a file.

Lines can have a key and no value (see booleanValue()). Comments must be at the start of the line. Values are left and right-trimmed, but can otherwise contain whitespace.

Definition at line 40 of file gmapfile.cpp.

◆ MapFile() [4/4]

G::MapFile::MapFile ( std::istream &  stream)
explicit

Constructor that reads from a stream.

Definition at line 50 of file gmapfile.cpp.

Member Function Documentation

◆ add()

void G::MapFile::add ( const std::string &  key,
const std::string &  value,
bool  clear = false 
)

Adds or updates a single item in the map.

If updating then by default the new value is appended with a comma separator.

Definition at line 405 of file gmapfile.cpp.

◆ booleanValue()

bool G::MapFile::booleanValue ( const std::string &  key,
bool  default_ 
) const

Returns a boolean value from the map.

Returns true if the key exists with an empty value. Returns the default if no such key.

Definition at line 262 of file gmapfile.cpp.

◆ check()

void G::MapFile::check ( const G::Path path,
const std::string &  kind = std::string() 
)
static

Throws if the file is invalid.

This is equivalent to constructing a temporary MapFile object, but it specifically does not do any logging.

Definition at line 138 of file gmapfile.cpp.

◆ contains()

bool G::MapFile::contains ( const std::string &  key) const

Returns true if the map contains the given key.

Definition at line 423 of file gmapfile.cpp.

◆ editInto()

void G::MapFile::editInto ( const G::Path path,
bool  make_backup,
bool  allow_read_error,
bool  allow_write_error 
) const

Edits an existing file so that its contents reflect this map.

Definition at line 177 of file gmapfile.cpp.

◆ expand()

std::string G::MapFile::expand ( const std::string &  value) const

Does one-pass variable substitution for the given string.

Sub-strings like "%xyz%" are replaced by 'value("xyz")' and "%%" is replaced by "%". If there is no appropriate value in the map then the sub-string is left alone (so "%xyz%" remains as "%xyz%" if there is no "xyz" map item).

Definition at line 335 of file gmapfile.cpp.

◆ expandedPathValue() [1/2]

G::Path G::MapFile::expandedPathValue ( const std::string &  key) const

Returns a mandatory path value from the map with expand().

Throws if it does not exist.

Definition at line 303 of file gmapfile.cpp.

◆ expandedPathValue() [2/2]

G::Path G::MapFile::expandedPathValue ( const std::string &  key,
const G::Path default_ 
) const

Returns a path value from the map with expand().

Definition at line 313 of file gmapfile.cpp.

◆ keys()

const G::StringArray & G::MapFile::keys ( ) const

Returns a reference to the internal ordered list of keys.

Definition at line 433 of file gmapfile.cpp.

◆ log()

void G::MapFile::log ( const std::string &  prefix = std::string()) const

Logs the contents.

Definition at line 144 of file gmapfile.cpp.

◆ map()

const G::StringMap & G::MapFile::map ( ) const

Returns a reference to the internal map.

Definition at line 428 of file gmapfile.cpp.

◆ numericValue()

unsigned int G::MapFile::numericValue ( const std::string &  key,
unsigned int  default_ 
) const

Returns a numeric value from the map.

Definition at line 318 of file gmapfile.cpp.

◆ pathValue() [1/2]

G::Path G::MapFile::pathValue ( const std::string &  key) const

Returns a mandatory path value from the map.

Throws if it does not exist.

Definition at line 298 of file gmapfile.cpp.

◆ pathValue() [2/2]

G::Path G::MapFile::pathValue ( const std::string &  key,
const G::Path default_ 
) const

Returns a path value from the map.

Definition at line 308 of file gmapfile.cpp.

◆ remove()

void G::MapFile::remove ( const std::string &  key)

Removes a value (if it exists).

Definition at line 324 of file gmapfile.cpp.

◆ value() [1/2]

std::string G::MapFile::value ( const std::string &  key,
const char *  default_ 
) const

Returns a string value from the map.

Definition at line 286 of file gmapfile.cpp.

◆ value() [2/2]

std::string G::MapFile::value ( const std::string &  key,
const std::string &  default_ = std::string() 
) const

Returns a string value from the map.

Returns the default if there is no such key or if the value is empty.

Definition at line 279 of file gmapfile.cpp.

◆ writeItem() [1/2]

void G::MapFile::writeItem ( std::ostream &  stream,
const std::string &  key 
) const

Writes a single item from this map to the stream.

Definition at line 160 of file gmapfile.cpp.

◆ writeItem() [2/2]

void G::MapFile::writeItem ( std::ostream &  stream,
const std::string &  key,
const std::string &  value 
)
static

Writes an arbitrary item to the stream.

Definition at line 166 of file gmapfile.cpp.


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