Class: Nanoc3::Store Abstract Private

Inherits:
Object
  • Object
show all
Defined in:
lib/nanoc3/base/store.rb

Overview

This class is part of a private API. You should avoid using this class if possible, as it may be removed or be changed in the future.

This class is abstract.

Subclasses must implement #data and #data=, and may implement #no_data_found and #version_mismatch_detected.

An abstract superclass for classes that need to store data to the filesystem, such as checksums, cached compiled content and dependency graphs.

Each store has a version number. When attempting to load data from a store that has an incompatible version number, no data will be loaded, but #version_mismatch_detected will be called.

Instance Attribute Summary collapse

Loading and storing data collapse

Callback methods collapse

Instance Method Summary collapse

Constructor Details

#initialize(filename, version) ⇒ Store

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Creates a new store for the given filename.

Parameters:

  • filename (String) —

    The name of the file where data will be loaded from and stored to.

  • version (Numeric) —

    The version number corresponding to the file format the data is in. When the file format changes, the version number should be incremented.



36
37
38
39
 
# File 'lib/nanoc3/base/store.rb', line 36

def initialize(filename, version)
  @filename = filename
  @version  = version
end

Instance Attribute Details

#filename ⇒ String (readonly)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns The name of the file where data will be loaded from and stored to.

Returns:

  • (String) —

    The name of the file where data will be loaded from and stored to.



21
22
23
 
# File 'lib/nanoc3/base/store.rb', line 21

def filename
  @filename
end

#version ⇒ Numeric (readonly)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns The version number corresponding to the file format the data is in. When the file format changes, the version number should be incremented.

Returns:

  • (Numeric) —

    The version number corresponding to the file format the data is in. When the file format changes, the version number should be incremented.



26
27
28
 
# File 'lib/nanoc3/base/store.rb', line 26

def version
  @version
end

Instance Method Details

#data ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

This method is abstract.

This method must be implemented by the subclass.

Returns The data that should be written to the disk.

Returns:

  • The data that should be written to the disk

Raises:

  • (NotImplementedError) 


46
47
48
 
# File 'lib/nanoc3/base/store.rb', line 46

def data
  raise NotImplementedError.new("Nanoc3::Store subclasses must implement #data and #data=")
end

#data=(new_data) ⇒ void

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

This method is abstract.

This method must be implemented by the subclass.

This method returns an undefined value.

Parameters:

  • new_data —

    The data that has been loaded from the disk

Raises:

  • (NotImplementedError) 


55
56
57
 
# File 'lib/nanoc3/base/store.rb', line 55

def data=(new_data)
  raise NotImplementedError.new("Nanoc3::Store subclasses must implement #data and #data=")
end

#load ⇒ void

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

This method returns an undefined value.

Loads the data from the filesystem into memory. This method will set the

loaded data using the {#data=} method.



63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
 
# File 'lib/nanoc3/base/store.rb', line 63

def load
  # Don’t load twice
  if @loaded
    return
  end

  # Check file existance
  if !File.file?(self.filename)
    no_data_found
    @loaded = true
    return
  end

  pstore.transaction do
    # Check version
    if pstore[:version] != self.version
      version_mismatch_detected
      @loaded = true
      return
    end

    # Load
    self.data = pstore[:data]
    @loaded = true
  end
end

#no_data_found ⇒ void

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

This method returns an undefined value.

Callback method that is called when no data file was found. By default, this implementation does nothing, but it should probably be overridden by the subclass.



116
117
 
# File 'lib/nanoc3/base/store.rb', line 116

def no_data_found
end

#store ⇒ void

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

This method returns an undefined value.

Stores the data contained in memory to the filesystem. This method will

use the {#data} method to fetch the data that should be written.



100
101
102
103
104
105
106
107
 
# File 'lib/nanoc3/base/store.rb', line 100

def store
  FileUtils.mkdir_p(File.dirname(self.filename))

  pstore.transaction do
    pstore[:data]    = self.data
    pstore[:version] = self.version
  end
end

#unload ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Undoes the effects of #load. Used when #load raises an exception.



93
94
 
# File 'lib/nanoc3/base/store.rb', line 93

def unload
end

#version_mismatch_detected ⇒ void

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

This method returns an undefined value.

Callback method that is called when a version mismatch is detected. By default, this implementation does nothing, but it should probably be overridden by the subclass.



124
125
 
# File 'lib/nanoc3/base/store.rb', line 124

def version_mismatch_detected
end