Module db_entry

Description
Data Types
Function Index
Function Details

Abstract datatype of a single DB entry.

Version: $Id$

Authors: Florian Schintke (schintke@onscale.de).

Description

Abstract datatype of a single DB entry.

Data Types

client_version()

client_version() = non_neg_integer()

only for unit tests:

entry()

entry() = entry_ex() | entry_empty()

entry_empty()

entry_empty() = 
    {Key :: rt_chord:key(),
     empty_val | db_dht:value(),
     WriteLock :: false | -1 | client_version(),
     ReadLock :: non_neg_integer(),
     Version :: -1}

entry_ex()

entry_ex() = 
    {Key :: rt_chord:key(),
     Value :: db_dht:value(),
     WriteLock :: false | client_version(),
     ReadLock :: non_neg_integer(),
     Version :: client_version()}

Function Index

dec_readlock/1
dec_version/1
get_key/1
get_readlock/1
get_value/1
get_version/1
get_writelock/1
inc_readlock/1
inc_version/1
is_empty/1	Returns whether the item is an empty_val item with version -1.
is_locked/1
is_null/1	Returns whether the item is an empty_val item with version -1 and no read or write locks.
lockcount/1	Returns how many read and write locks are currently set.
new/1
new/3
reset_locks/1
set_value/3
set_writelock/2
unset_writelock/1

Function Details

new/1

new(Key :: rt_chord:key()) ->
       {rt_chord:key(), empty_val, false, 0, -1}

new/3

new(Key :: rt_chord:key(),
    Value :: db_dht:value(),
    Version :: client_version()) ->
       {Key :: rt_chord:key(),
        Value :: db_dht:value(),
        WriteLock :: false,
        ReadLock :: 0,
        Version :: client_version()}

get_key/1

get_key(DBEntry :: entry()) -> rt_chord:key()

get_value/1

get_value(DBEntry :: entry()) -> db_dht:value()

set_value/3

set_value(DBEntry :: entry(),
          Value :: db_dht:value(),
          Version :: client_version()) ->
             entry()

get_writelock/1

get_writelock(DBEntry :: entry()) ->
                 WriteLock :: false | -1 | client_version()

set_writelock/2

set_writelock(DBEntry :: entry_ex(),
              WriteLock :: false | client_version()) ->
                 entry_ex()

unset_writelock/1

unset_writelock(DBEntry :: entry()) -> entry()

get_readlock/1

get_readlock(DBEntry :: entry()) -> ReadLock :: non_neg_integer()

inc_readlock/1

inc_readlock(DBEntry :: entry()) -> entry()

dec_readlock/1

dec_readlock(DBEntry :: entry()) -> entry()

get_version/1

get_version(DBEntry :: entry()) -> client_version() | -1

inc_version/1

inc_version(DBEntry :: entry()) -> entry()

dec_version/1

dec_version(DBEntry :: entry()) -> entry()

reset_locks/1

reset_locks(DBEntry :: entry()) ->
               {Key :: rt_chord:key(),
                Value :: db_dht:value(),
                WriteLock :: false,
                ReadLock :: 0,
                Version :: client_version()} |
               {Key :: rt_chord:key(),
                empty_val | db_dht:value(),
                WriteLock :: false,
                ReadLock :: 0,
                Version :: -1}

is_locked/1

is_locked(DBEntry :: entry()) -> boolean()

is_empty/1

is_empty(X1 :: entry()) -> boolean()

Returns whether the item is an empty_val item with version -1. Note: The number of read or write locks does not matter here!

is_null/1

is_null(X1 :: entry()) -> boolean()

Returns whether the item is an empty_val item with version -1 and no read or write locks.

lockcount/1

lockcount(Entry :: db_entry:entry()) -> integer()

Returns how many read and write locks are currently set.

Generated by EDoc, Apr 22 2017, 16:02:53.