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110 lines
3.3 KiB
110 lines
3.3 KiB
require 'yaml' |
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module Squib |
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# Internal class for handling layouts |
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# @api private |
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class LayoutParser |
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def initialize(dpi = 300) |
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@dpi = dpi |
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end |
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# Load the layout file(s), if exists |
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# @api private |
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def load_layout(files, initial = {}) |
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layout = initial |
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Squib::logger.info { " using layout(s): #{files}" } |
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Array(files).each do |file| |
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thefile = file |
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thefile = builtin(file) unless File.exists?(file) |
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if File.exists? thefile |
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# note: YAML.load_file returns false on empty file |
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yml = layout.merge(YAML.load_file(thefile) || {}) |
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yml.each do |key, value| |
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layout[key] = recurse_extends(yml, key, {}) |
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end |
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else |
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Squib::logger.error { "Layout file not found: #{file}. Skipping..." } |
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end |
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end |
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return layout |
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end |
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private |
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# Determine the file path of the built-in layout file |
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def builtin(file) |
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"#{File.dirname(__FILE__)}/layouts/#{file}" |
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end |
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# Process the extends recursively |
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# :nodoc: |
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# @api private |
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def recurse_extends(yml, key, visited) |
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assert_not_visited(key, visited) |
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return yml[key] unless has_extends?(yml, key) |
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return yml[key] unless parents_exist?(yml, key) |
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visited[key] = key |
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parent_keys = [yml[key]['extends']].flatten |
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h = {} |
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parent_keys.each do |parent_key| |
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from_extends = yml[key].merge(recurse_extends(yml, parent_key, visited)) do |key, child_val, parent_val| |
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if child_val.to_s.strip.start_with?('+=') |
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add_parent_child(parent_val, child_val) |
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elsif child_val.to_s.strip.start_with?('-=') |
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sub_parent_child(parent_val, child_val) |
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else |
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child_val # child overrides parent when merging, no += |
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end |
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end |
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h = h.merge(from_extends) do |key, older_sibling, younger_sibling| |
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younger_sibling # when two siblings have the same entry, the "younger" (lower one) overrides |
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end |
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end |
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return h |
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end |
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def add_parent_child(parent, child) |
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parent_pixels = Args::UnitConversion.parse(parent, @dpi).to_f |
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child_pixels = Args::UnitConversion.parse(child.sub('+=', ''), @dpi).to_f |
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parent_pixels + child_pixels |
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end |
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def sub_parent_child(parent, child) |
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parent_pixels = Args::UnitConversion.parse(parent, @dpi).to_f |
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child_pixels = Args::UnitConversion.parse(child.sub('-=', ''), @dpi).to_f |
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parent_pixels - child_pixels |
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end |
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# Does this layout entry have an extends field? |
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# i.e. is it a base-case or will it need recursion? |
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# :nodoc: |
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# @api private |
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def has_extends?(yml, key) |
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!!yml[key] && yml[key].key?('extends') |
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end |
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# Checks if we have any absentee parents |
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# @api private |
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def parents_exist?(yml, key) |
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exists = true |
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Array(yml[key]['extends']).each do |parent| |
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unless yml.key?(parent) |
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exists = false unless |
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Squib.logger.error "Processing layout: '#{key}' attempts to extend a missing '#{yml[key]['extends']}'" |
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end |
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end |
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return exists |
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end |
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# Safeguard against malformed circular extends |
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# :nodoc: |
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# @api private |
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def assert_not_visited(key, visited) |
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if visited.key? key |
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raise "Invalid layout: circular extends with '#{key}'" |
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end |
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end |
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end |
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end
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