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 # 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 104 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 89 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 73 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 56 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