The class handles `.sss` 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 `.sss` file, the class-level {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.
TODO: attach this to a compiler instance. @private
Creates a new StalenessChecker for checking the staleness of several stylesheets at once.
@param options [{Symbol => Object}]
See {file:SASS_REFERENCE.md#sass_options the Sass options documentation}.
# File lib/sass/plugin/staleness_checker.rb, line 39 def initialize(options) @dependencies = self.class.dependencies_cache # 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 automaticaly 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
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.
@param template_file [String] The location of the Sass or SCSS template. @param mtime [Fixnum] The modification time to check against. @param importer [Sass::Importers::Base] The importer used to locate the stylesheet.
Defaults to the filesystem importer.
@return [Boolean] Whether the stylesheet has been modified.
# File lib/sass/plugin/staleness_checker.rb, line 108 def self.stylesheet_modified_since?(template_file, mtime, importer = nil) new(Plugin.engine_options).stylesheet_modified_since?(template_file, mtime, importer) end
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.
@param css_file [String] The location of the CSS file to check. @param template_file [String] The location of the Sass or SCSS template
that is compiled to `css_file`.
@return [Boolean] Whether the stylesheet needs to be updated.
# File lib/sass/plugin/staleness_checker.rb, line 93 def self.stylesheet_needs_update?(css_file, template_file, importer = nil) new(Plugin.engine_options).stylesheet_needs_update?(css_file, template_file, importer) end
Returns whether a Sass or SCSS stylesheet has been modified since a given time.
@param template_file [String] The location of the Sass or SCSS template. @param mtime [Fixnum] The modification time to check against. @param importer [Sass::Importers::Base] The importer used to locate the stylesheet.
Defaults to the filesystem importer.
@return [Boolean] Whether the stylesheet has been modified.
# File lib/sass/plugin/staleness_checker.rb, line 77 def stylesheet_modified_since?(template_file, mtime, importer = nil) importer ||= @options[:filesystem_importer].new(".") dependency_updated?(mtime).call(template_file, importer) end
Returns whether or not a given CSS file is out of date and needs to be regenerated.
@param css_file [String] The location of the CSS file to check. @param template_file [String] The location of the Sass or SCSS template
that is compiled to `css_file`.
@return [Boolean] Whether the stylesheet needs to be updated.
# File lib/sass/plugin/staleness_checker.rb, line 60 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
# File lib/sass/plugin/staleness_checker.rb, line 168 def compute_dependencies(uri, importer) tree(uri, importer).grep(Tree::ImportNode) do |n| next if n.css_import? file = n.imported_file key = [file.options[:filename], file.options[:importer]] @parse_trees[key] = file.to_tree key end.compact end
# File lib/sass/plugin/staleness_checker.rb, line 142 def dependencies(uri, importer) stored_mtime, dependencies = Sass::Util.destructure(@dependencies[[uri, importer]]) if !stored_mtime || stored_mtime < mtime(uri, importer) dependencies = compute_dependencies(uri, importer) @dependencies[[uri, importer]] = [mtime(uri, importer), dependencies] end dependencies end
# File lib/sass/plugin/staleness_checker.rb, line 114 def dependencies_stale?(uri, importer, css_mtime) timestamps = @dependencies_stale[[uri, importer]] ||= {} timestamps.each_pair do |checked_css_mtime, is_stale| if checked_css_mtime <= css_mtime && !is_stale return false elsif checked_css_mtime > css_mtime && is_stale return true end end timestamps[css_mtime] = dependencies(uri, importer).any?(&dependency_updated?(css_mtime)) rescue Sass::SyntaxError # If there's an error finding dependencies, default to recompiling. true end
# File lib/sass/plugin/staleness_checker.rb, line 153 def dependency_updated?(css_mtime) Proc.new do |uri, importer| next true if @actively_checking.include?(uri) begin @actively_checking << uri sass_mtime = mtime(uri, importer) !sass_mtime || sass_mtime > css_mtime || dependencies_stale?(uri, importer, css_mtime) ensure @actively_checking.delete uri end end end
# File lib/sass/plugin/staleness_checker.rb, line 129 def mtime(uri, importer) @mtimes[[uri, importer]] ||= begin mtime = importer.mtime(uri, @options) if mtime.nil? @dependencies.delete([uri, importer]) nil else mtime end end end
# File lib/sass/plugin/staleness_checker.rb, line 178 def tree(uri, importer) @parse_trees[[uri, importer]] ||= importer.find(uri, @options).to_tree end