#include <misc.h>
Inheritance diagram for Keydata:
Public Methods | |
Keydata () | |
Create an empty key data object. | |
Keydata (const char *keypath, const char *environment="CONFIG_KEYDATA") | |
Create a new key data object and use "Load" method to load an initial config file section into it. More... | |
virtual | ~Keydata () |
Destroy the keydata object and all allocated memory. More... | |
void | Unlink (void) |
Unlink the keydata object from the cache file stream. More... | |
int | getCount (const char *sym) |
Get a count of the number of data "values" that is associated with a specific keyword. More... | |
const char* | getFirst (const char *sym) |
Get the first data value for a given keyword. More... | |
const char* | getLast (const char *sym) |
Get the last (most recently set) value for a given keyword. More... | |
int | getIndex (char **data, int max) |
Get an index array of ALL keywords that are stored by the current keydata object. More... | |
void | setValue (const char *sym, const char *data) |
Set (replace) the value of a given keyword. More... | |
const char* const* | getList (const char *sym) |
Return a list of all values set for the given keyword returned in order. More... | |
void | clrValue (const char *sym) |
Clear all values associated with a given keyword. More... | |
const char* | operator[] (const char *keyword) |
A convient notation for accessing the keydata as an associative array of keyword/value pairs through the [] operator. | |
Protected Methods | |
keysym_t* | getSymbol (const char *sym, bool create) |
void | Load (const char *keypath, const char *environment="CONFIG_KEYDATA") |
Load additional key values into the currrent object from the specfied config source (a config file/section pair). More... | |
void | Load (KEYDEF *pairs) |
Load default keywords into the current object. More... | |
Friends | |
void | endKeydata (void) |
Shutdown the file stream cache. More... |
Each "keydata" object holds the key pairs from a [section] of a text readable config file. The /etc directory is presumed to hold the referenced file key set unless a ~ is used.
Keydata can hold multiple values for the same key pair. This can occur either from storing a "list" of data items in a config file, or when overlaying multiple config sources (such as /etc/....conf and ~/.confrc segments) into a single object. The keys are stored as cumulative (read-only/replacable) config values under a hash index system for quick retrieval.
The most useful of the misc. classes is the Keydata class. This class is used to load and then hold "keyword = value" pairs parsed from a text based "config" file that has been divided into "[sections]". Keydata can also load a table of "initialization" values for keyword pairs that were not found in the external file.
One typically derives an application specific keydata class to load a specific portion of a known config file and initialize it's values. One can then declare a global instance of these objects and have configuration data initialized automatically as the executable is loaded.
Hence, if I have a "[paths]" section in a "/etc/server.conf" file, I might define something like:
class KeyPaths : public Keydata { public: KeyPaths() : Keydata("/server/paths") { static KEYDEF *defvalues = { {"datafiles", "/var/server"}, {NULL, NULL}};
// override with [paths] from "~/.serverrc" if avail.
Load("~server/paths"); Load(defvalues); } };
KeyPaths keypaths;
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Create an empty key data object.
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Create a new key data object and use "Load" method to load an initial config file section into it.
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Destroy the keydata object and all allocated memory. This may also clear the "cache" file stream if no other keydata objects currently reference it. |
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Load default keywords into the current object. This only loads keyword entries which have not already been defined to reduce memory usage. This form of Load is also commonly used in the constructor of a derived Keydata class.
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Load additional key values into the currrent object from the specfied config source (a config file/section pair). These values will overlay the current keywords when matches are found. This can be used typically in a derived config object class constructor to first load a /etc section, and then load a matching user specific entry from ~/. to override default system values with user specific keyword values.
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Unlink the keydata object from the cache file stream. This should be used if you plan to keepa Keydata object after it is loaded once all keydata objects have been loaded, otherwise the cfgFile stream will remain open. You can also use endKeydata. |
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Clear all values associated with a given keyword. This does not de-allocate the keyword from memory, however.
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Get a count of the number of data "values" that is associated with a specific keyword. Each value is from an accumulation of "load()" requests.
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Get the first data value for a given keyword. This will typically be the /etc set global default.
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Get an index array of ALL keywords that are stored by the current keydata object.
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Get the last (most recently set) value for a given keyword. This is typically the value actually used.
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Return a list of all values set for the given keyword returned in order.
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A convient notation for accessing the keydata as an associative array of keyword/value pairs through the [] operator.
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Set (replace) the value of a given keyword. This new value will become the value returned from getLast(), while the prior value will still be stored and found from getList().
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Shutdown the file stream cache. This should be used before detaching a deamon, exec(), fork(), etc. |