Class: Moneta::Adapters::LRUHash

Inherits:
Object
  • Object
show all
Includes:
CreateSupport, Defaults, IncrementSupport
Defined in:
lib/moneta/adapters/lruhash.rb

Overview

LRUHash backend

Based on Hashery::LRUHash but simpler and measures both memory usage and hash size.

Defined Under Namespace

Classes: Entry

Constant Summary collapse

DEFAULT_MAX_SIZE =
1024000
DEFAULT_MAX_COUNT =
10240

Instance Method Summary collapse

Methods included from CreateSupport

#create, included

Methods included from IncrementSupport

included, #increment

Methods included from Defaults

#[], #[]=, #close, #create, #decrement, #features, #fetch, #fetch_values, included, #increment, #merge!, #supports?, #update

Methods included from OptionSupport

#expires, #prefix, #raw, #with

Constructor Details

#initialize(options = {}) ⇒ LRUHash

Returns a new instance of LRUHash

Parameters:

  • options (Hash) (defaults to: {})

Options Hash (options):

  • :max_size (Integer) — default: 1024000

    Maximum byte size of all values, nil disables the limit

  • :max_value (Integer) — default: options[:max_size]

    Maximum byte size of one value, nil disables the limit

  • :max_count (Integer) — default: 10240

    Maximum number of values, nil disables the limit


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# File 'lib/moneta/adapters/lruhash.rb', line 22

def initialize(options = {})
  @max_size = options.fetch(:max_size) { DEFAULT_MAX_SIZE }
  @max_count = options.fetch(:max_count) { DEFAULT_MAX_COUNT }
  @max_value = [options[:max_value], @max_size].compact.min
  clear
end

Instance Method Details

#clear(options = {}) ⇒ void

This method returns an undefined value.

Clear all keys in this store

Parameters:

  • options (Hash) (defaults to: {})

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# File 'lib/moneta/adapters/lruhash.rb', line 79

def clear(options = {})
  @entry, @size = {}, 0
  @list = Entry.new
  @list.prev = @list.next = @list
  self
end

#delete(key, options = {}) ⇒ Object

Delete the key from the store and return the current value

Parameters:

  • key (Object)
  • options (Hash) (defaults to: {})

Options Hash (options):

  • :raw (Boolean)

    Raw access without value transformation (See Transformer)

  • :prefix (String)

    Prefix key (See Transformer)

  • Other (Object)

    options as defined by the adapters or middleware

Returns:

  • (Object)

    current value


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# File 'lib/moneta/adapters/lruhash.rb', line 70

def delete(key, options = {})
  if entry = @entry.delete(key)
    @size -= entry.value.bytesize if @max_size
    entry.unlink
    entry.value
  end
end

#each_keyEnumerator #each_key {|key| ... } ⇒ self

Note:

Not every Moneta store implements this method, a NotImplementedError is raised if it is not supported.

Calls block once for each key in store, passing the key as a parameter. If no block is given, an enumerator is returned instead.

Overloads:

  • #each_keyEnumerator

    Returns An all-the-keys enumerator

    Returns:

    • (Enumerator)

      An all-the-keys enumerator

  • #each_key {|key| ... } ⇒ self

    Yield Parameters:

    • key (Object)

      Each key is yielded to the supplied block

    Returns:

    • (self)

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# File 'lib/moneta/adapters/lruhash.rb', line 35

def each_key(&block)
  return enum_for(:each_key) { @entry.length } unless block_given?

  @entry.each_key { |k| yield(k) }
  self
end

#key?(key, options = {}) ⇒ Boolean

Exists the value with key

Parameters:

  • key (Object)
  • options (Hash) (defaults to: {})

Options Hash (options):

  • :expires (Integer)

    Update expiration time (See Expires)

  • :prefix (String)

    Prefix key (See Transformer)

  • Other (Object)

    options as defined by the adapters or middleware

Returns:

  • (Boolean)

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# File 'lib/moneta/adapters/lruhash.rb', line 30

def key?(key, options = {})
  @entry.key?(key)
end

#load(key, options = {}) ⇒ Object

Fetch value with key. Return nil if the key doesn't exist

Parameters:

  • key (Object)
  • options (Hash) (defaults to: {})

Options Hash (options):

  • :expires (Integer)

    Update expiration time (See Expires)

  • :raw (Boolean)

    Raw access without value transformation (See Transformer)

  • :prefix (String)

    Prefix key (See Transformer)

  • :sync (Boolean)

    Synchronized load (Cache reloads from adapter, Daybreak syncs with file)

  • Other (Object)

    options as defined by the adapters or middleware

Returns:

  • (Object)

    value


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# File 'lib/moneta/adapters/lruhash.rb', line 43

def load(key, options = {})
  if entry = @entry[key]
    entry.insert_after(@list)
    entry.value
  end
end

#slice(*keys, **options) ⇒ <(Object, Object)>

Note:

The keys in the return value may be the same objects that were supplied (i.e. Object#equal?), or may simply be equal (i.e. Object#==).

Note:

Some adapters may implement this method atomically. The default implmentation uses #values_at.

Returns a collection of key-value pairs corresponding to those supplied keys which are present in the key-value store, and their associated values. Only those keys present in the store will have pairs in the return value. The return value can be any enumerable object that yields pairs, so it could be a hash, but needn't be.

Parameters:

  • keys (<Object>)

    The keys for the values to fetch

  • options (Hash)

Options Hash (**options):

  • :expires (Integer)

    Update expiration time (See Expires)

  • :raw (Boolean)

    Raw access without value transformation (See Transformer)

  • :prefix (String)

    Prefix key (See Transformer)

  • :sync (Boolean)

    Synchronized load (Cache reloads from adapter, Daybreak syncs with file)

  • Other (Object)

    options as defined by the adapters or middleware

Returns:

  • (<(Object, Object)>)

    A collection of key-value pairs


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# File 'lib/moneta/adapters/lruhash.rb', line 97

def slice(*keys, **options)
  return super unless @entry.respond_to?(:slice)
  hash = @entry.slice(*keys)
  hash.each do |key, entry|
    entry.insert_after(@list)
    hash[key] = entry.value
  end
end

#store(key, value, options = {}) ⇒ Object

Store value with key

Parameters:

  • key (Object)
  • value (Object)
  • options (Hash) (defaults to: {})

Options Hash (options):

  • :expires (Integer)

    Set expiration time (See Expires)

  • :raw (Boolean)

    Raw access without value transformation (See Transformer)

  • :prefix (String)

    Prefix key (See Transformer)

  • Other (Object)

    options as defined by the adapters or middleware

Returns:

  • value


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# File 'lib/moneta/adapters/lruhash.rb', line 51

def store(key, value, options = {})
  if @max_value && value.bytesize > @max_value
    delete(key)
  else
    if entry = @entry[key]
      @size -= entry.value.bytesize if @max_size
    else
      @entry[key] = entry = Entry.new
      entry.key = key
    end
    entry.value = value
    @size += entry.value.bytesize if @max_size
    entry.insert_after(@list)
    delete(@list.prev.key) while @list.next != @list.prev && (@max_size && @size > @max_size || @max_count && @entry.size > @max_count)
  end
  value
end

#values_at(*keys, **options) ⇒ Array<Object, nil>

Note:

Some adapters may implement this method atomically, but the default implementation simply makes repeated calls to #load.

Returns an array containing the values associated with the given keys, in the same order as the supplied keys. If a key is not present in the key-value-store, nil is returned in its place.

Parameters:

  • keys (<Object>)

    The keys for the values to fetch

  • options (Hash)

Options Hash (**options):

  • :expires (Integer)

    Update expiration time (See Expires)

  • :raw (Boolean)

    Raw access without value transformation (See Transformer)

  • :prefix (String)

    Prefix key (See Transformer)

  • :sync (Boolean)

    Synchronized load (Cache reloads from adapter, Daybreak syncs with file)

  • Other (Object)

    options as defined by the adapters or middleware

Returns:

  • (Array<Object, nil>)

    Array containing the values requested, with nil for missing values


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# File 'lib/moneta/adapters/lruhash.rb', line 87

def values_at(*keys, **options)
  @entry.values_at(*keys).map do |entry|
    if entry
      entry.insert_after(@list)
      entry.value
    end
  end
end