Class: Sass::Plugin::StalenessChecker

Inherits:
Object
  • Object
show all
Defined in:
lib/sass/plugin/staleness_checker.rb

Overview

The class handles .s[ca]ss file staleness checks via their mtime timestamps.

To speed things up two level of caches are employed:

  • A class-level dependency cache which stores @import paths for each file. This is a long-lived cache that is reused by every StalenessChecker instance.
  • Three short-lived instance-level caches, one for file mtimes, one for whether a file is stale during this particular run. and one for the parse tree for a file. These are only used by a single StalenessChecker instance.

Usage:

  • For a one-off staleness check of a single .s[ca]ss file, the class-level StalenessChecker.stylesheet_needs_update? method should be used.
  • For a series of staleness checks (e.g. checking all files for staleness) a StalenessChecker instance should be created, and the instance-level #stylesheet_needs_update? method should be used. the caches should make the whole process significantly faster. WARNING: It is important not to retain the instance for too long, as its instance-level caches are never explicitly expired.

Class Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options) ⇒ StalenessChecker

Creates a new StalenessChecker for checking the staleness of several stylesheets at once.

Parameters:



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# File 'lib/sass/plugin/staleness_checker.rb', line 43

def initialize(options)
  # URIs that are being actively checked for staleness. Protects against
  # import loops.
  @actively_checking = Set.new

  # Entries in the following instance-level caches are never explicitly expired.
  # Instead they are supposed to automatically go out of scope when a series of staleness
  # checks (this instance of StalenessChecker was created for) is finished.
  @mtimes, @dependencies_stale, @parse_trees = {}, {}, {}
  @options = Sass::Engine.normalize_options(options)
end

Class Attribute Details

.dependency_cache_mutex (readonly)

Returns the value of attribute dependency_cache_mutex.



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# File 'lib/sass/plugin/staleness_checker.rb', line 35

def dependency_cache_mutex
  @dependency_cache_mutex
end

Class Method Details

.stylesheet_modified_since?(template_file, mtime, importer = nil) ⇒ Boolean

Returns whether a Sass or SCSS stylesheet has been modified since a given time.

The distinction between this method and the instance-level #stylesheet_modified_since? is that the instance method preserves mtime and stale-dependency caches, so it's better to use when checking multiple stylesheets at once.

Parameters:

  • template_file (String) —

    The location of the Sass or SCSS template.

  • mtime (Time) —

    The modification time to check against.

  • importer (Sass::Importers::Base) (defaults to: nil) —

    The importer used to locate the stylesheet. Defaults to the filesystem importer.

Returns:

  • (Boolean) —

    Whether the stylesheet has been modified.



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# File 'lib/sass/plugin/staleness_checker.rb', line 110

def self.stylesheet_modified_since?(template_file, mtime, importer = nil)
  new(Plugin.engine_options).stylesheet_modified_since?(template_file, mtime, importer)
end

.stylesheet_needs_update?(css_file, template_file, importer = nil) ⇒ Boolean

Returns whether or not a given CSS file is out of date and needs to be regenerated.

The distinction between this method and the instance-level #stylesheet_needs_update? is that the instance method preserves mtime and stale-dependency caches, so it's better to use when checking multiple stylesheets at once.

Parameters:

  • css_file (String) —

    The location of the CSS file to check.

  • template_file (String) —

    The location of the Sass or SCSS template that is compiled to css_file.

Returns:

  • (Boolean) —

    Whether the stylesheet needs to be updated.



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# File 'lib/sass/plugin/staleness_checker.rb', line 95

def self.stylesheet_needs_update?(css_file, template_file, importer = nil)
  new(Plugin.engine_options).stylesheet_needs_update?(css_file, template_file, importer)
end

Instance Method Details

#stylesheet_modified_since?(template_file, mtime, importer = nil) ⇒ Boolean

Returns whether a Sass or SCSS stylesheet has been modified since a given time.

Parameters:

  • template_file (String) —

    The location of the Sass or SCSS template.

  • mtime (Time) —

    The modification time to check against.

  • importer (Sass::Importers::Base) (defaults to: nil) —

    The importer used to locate the stylesheet. Defaults to the filesystem importer.

Returns:

  • (Boolean) —

    Whether the stylesheet has been modified.



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# File 'lib/sass/plugin/staleness_checker.rb', line 79

def stylesheet_modified_since?(template_file, mtime, importer = nil)
  importer ||= @options[:filesystem_importer].new(".")
  dependency_updated?(mtime).call(template_file, importer)
end

#stylesheet_needs_update?(css_file, template_file, importer = nil) ⇒ Boolean

Returns whether or not a given CSS file is out of date and needs to be regenerated.

Parameters:

  • css_file (String) —

    The location of the CSS file to check.

  • template_file (String) —

    The location of the Sass or SCSS template that is compiled to css_file.

Returns:

  • (Boolean) —

    Whether the stylesheet needs to be updated.



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# File 'lib/sass/plugin/staleness_checker.rb', line 62

def stylesheet_needs_update?(css_file, template_file, importer = nil)
  template_file = File.expand_path(template_file)
  begin
    css_mtime = File.mtime(css_file)
  rescue Errno::ENOENT
    return true
  end
  stylesheet_modified_since?(template_file, css_mtime, importer)
end