[project/luci.git] / modules / luci-base / luasrc / util.luadoc

---[[
LuCI utility functions.

module "luci.util"
]]

---[[
Create a Class object (Python-style object model).

The class object can be instantiated by calling itself.
Any class functions or shared parameters can be attached to this object.
Attaching a table to the class object makes this table shared between
all instances of this class. For object parameters use the __init__ function.
Classes can inherit member functions and values from a base class.
Class can be instantiated by calling them. All parameters will be passed
to the __init__ function of this class - if such a function exists.
The __init__ function must be used to set any object parameters that are not shared
with other objects of this class. Any return values will be ignored.
@class function
@name class
@param base     The base class to inherit from (optional)
@return         A class object
@see                    instanceof
@see                    clone
]]

---[[
Test whether the given object is an instance of the given class.

@class function
@name instanceof
@param object   Object instance
@param class            Class object to test against
@return                 Boolean indicating whether the object is an instance
@see                            class
@see                            clone
]]

---[[
Create a new or get an already existing thread local store associated with

the current active coroutine. A thread local store is private a table object
whose values can't be accessed from outside of the running coroutine.
@class function
@name threadlocal
@return Table value representing the corresponding thread local store
]]

---[[
Write given object to stderr.

@class function
@name perror
@param obj      Value to write to stderr
@return         Boolean indicating whether the write operation was successful
]]

---[[
Recursively dumps a table to stdout, useful for testing and debugging.

@class function
@name dumptable
@param t        Table value to dump
@param maxdepth Maximum depth
@return Always nil
]]

---[[
Create valid XML PCDATA from given string.

@class function
@name pcdata
@param value    String value containing the data to escape
@return         String value containing the escaped data
]]

---[[
Strip HTML tags from given string.

@class function
@name striptags
@param value    String containing the HTML text
@return String with HTML tags stripped of
]]

---[[
Splits given string on a defined separator sequence and return a table

containing the resulting substrings. The optional max parameter specifies
the number of bytes to process, regardless of the actual length of the given
string. The optional last parameter, regex, specifies whether the separator
sequence is interpreted as regular expression.
@class function
@name split
@param str              String value containing the data to split up
@param pat              String with separator pattern (optional, defaults to "\n")
@param max              Maximum times to split (optional)
@param regex    Boolean indicating whether to interpret the separator
--                                      pattern as regular expression (optional, default is false)
@return                 Table containing the resulting substrings
]]

---[[
Remove leading and trailing whitespace from given string value.

@class function
@name trim
@param str      String value containing whitespace padded data
@return         String value with leading and trailing space removed
]]

---[[
Count the occurences of given substring in given string.

@class function
@name cmatch
@param str              String to search in
@param pattern  String containing pattern to find
@return                 Number of found occurences
]]

---[[
Return a matching iterator for the given value. The iterator will return

one token per invocation, the tokens are separated by whitespace. If the
input value is a table, it is transformed into a string first. A nil value
will result in a valid interator which aborts with the first invocation.
@class function
@name imatch
@param val              The value to scan (table, string or nil)
@return                 Iterator which returns one token per call
]]

---[[
Parse certain units from the given string and return the canonical integer

value or 0 if the unit is unknown. Upper- or lower case is irrelevant.
Recognized units are:
--      o "y"   - one year   (60*60*24*366)
 o "m"  - one month  (60*60*24*31)
 o "w"  - one week   (60*60*24*7)
 o "d"  - one day    (60*60*24)
 o "h"  - one hour       (60*60)
 o "min"        - one minute (60)
 o "kb"  - one kilobyte (1024)
 o "mb" - one megabyte (1024*1024)
 o "gb" - one gigabyte (1024*1024*1024)
 o "kib" - one si kilobyte (1000)
 o "mib"        - one si megabyte (1000*1000)
 o "gib"        - one si gigabyte (1000*1000*1000)
@class function
@name parse_units
@param ustr     String containing a numerical value with trailing unit
@return         Number containing the canonical value
]]

---[[
Appends numerically indexed tables or single objects to a given table.

@class function
@name append
@param src      Target table
@param ...      Objects to insert
@return         Target table
]]

---[[
Combines two or more numerically indexed tables and single objects into one table.

@class function
@name combine
@param tbl1     Table value to combine
@param tbl2     Table value to combine
@param ...      More tables to combine
@return         Table value containing all values of given tables
]]

---[[
Checks whether the given table contains the given value.

@class function
@name contains
@param table    Table value
@param value    Value to search within the given table
@return         Boolean indicating whether the given value occurs within table
]]

---[[
Update values in given table with the values from the second given table.

Both table are - in fact - merged together.
@class function
@name update
@param t                        Table which should be updated
@param updates  Table containing the values to update
@return                 Always nil
]]

---[[
Retrieve all keys of given associative table.

@class function
@name keys
@param t        Table to extract keys from
@return Sorted table containing the keys
]]

---[[
Clones the given object and return it's copy.

@class function
@name clone
@param object   Table value to clone
@param deep             Boolean indicating whether to do recursive cloning
@return                 Cloned table value
]]

---[[
Create a dynamic table which automatically creates subtables.

@class function
@name dtable
@return Dynamic Table
]]

---[[
Recursively serialize given data to lua code, suitable for restoring

with loadstring().
@class function
@name serialize_data
@param val      Value containing the data to serialize
@return         String value containing the serialized code
@see                    restore_data
@see                    get_bytecode
]]

---[[
Restore data previously serialized with serialize_data().

@class function
@name restore_data
@param str      String containing the data to restore
@return         Value containing the restored data structure
@see                    serialize_data
@see                    get_bytecode
]]

---[[
Return the current runtime bytecode of the given data. The byte code

will be stripped before it is returned.
@class function
@name get_bytecode
@param val      Value to return as bytecode
@return         String value containing the bytecode of the given data
]]

---[[
Strips unnescessary lua bytecode from given string. Information like line

numbers and debugging numbers will be discarded. Original version by
Peter Cawley (http://lua-users.org/lists/lua-l/2008-02/msg01158.html)
@class function
@name strip_bytecode
@param code     String value containing the original lua byte code
@return         String value containing the stripped lua byte code
]]

---[[
Return a key, value iterator which returns the values sorted according to

the provided callback function.
@class function
@name spairs
@param t        The table to iterate
@param f A callback function to decide the order of elements
@return Function value containing the corresponding iterator
]]

---[[
Return a key, value iterator for the given table.

The table pairs are sorted by key.
@class function
@name kspairs
@param t        The table to iterate
@return Function value containing the corresponding iterator
]]

---[[
Return a key, value iterator for the given table.

The table pairs are sorted by value.
@class function
@name vspairs
@param t        The table to iterate
@return Function value containing the corresponding iterator
]]

---[[
Test whether the current system is operating in big endian mode.

@class function
@name bigendian
@return Boolean value indicating whether system is big endian
]]

---[[
Execute given commandline and gather stdout.

@class function
@name exec
@param command  String containing command to execute
@return                 String containing the command's stdout
]]

---[[
Return a line-buffered iterator over the output of given command.

@class function
@name execi
@param command  String containing the command to execute
@return                 Iterator
]]

---[[
Issue an ubus call.

@class function
@name ubus
@param object           String containing the ubus object to call
@param method           String containing the ubus method to call
@param values           Table containing the values to pass
@return                 Table containin the ubus result
]]

---[[
Convert data structure to JSON

@class function
@name serialize_json
@param data             The data to serialize
@param writer   A function to write a chunk of JSON data (optional)
@return                 String containing the JSON if called without write callback
]]

---[[
Returns the absolute path to LuCI base directory.

@class function
@name libpath
@return         String containing the directory path
]]

---[[
This is a coroutine-safe drop-in replacement for Lua's "xpcall"-function

@class function
@name coxpcall
@param f                Lua function to be called protected
@param err      Custom error handler
@param ...      Parameters passed to the function
@return         A boolean whether the function call succeeded and the return
--                              values of either the function or the error handler
]]

---[[
This is a coroutine-safe drop-in replacement for Lua's "pcall"-function

@class function
@name copcall
@param f                Lua function to be called protected
@param ...      Parameters passed to the function
@return         A boolean whether the function call succeeded and the returns
--                              values of the function or the error object
]]