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#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements. See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
require 'liquid'
require 'pygments'
module Jekyll
class IncludeExampleTag < Liquid::Tag
def initialize(tag_name, markup, tokens)
@markup = markup
super
end
def render(context)
site = context.registers[:site]
config_dir = '../examples/src/main'
@code_dir = File.join(site.source, config_dir)
clean_markup = @markup.strip
parts = clean_markup.strip.split(' ')
if parts.length > 1 then
@snippet_label = ':' + parts[0]
snippet_file = parts[1]
else
@snippet_label = ''
snippet_file = parts[0]
end
@file = File.join(@code_dir, snippet_file)
@lang = snippet_file.split('.').last
code = File.open(@file).read.encode("UTF-8")
code = select_lines(code)
rendered_code = Pygments.highlight(code, :lexer => @lang)
hint = "<div><small>Find full example code at " \
"\"examples/src/main/#{snippet_file}\" in the Spark repo.</small></div>"
rendered_code + hint
end
# Trim the code block so as to have the same indention, regardless of their positions in the
# code file.
def trim_codeblock(lines)
# Select the minimum indention of the current code block.
min_start_spaces = lines
.select { |l| l.strip.size !=0 }
.map { |l| l[/\A */].size }
.min
lines.map { |l| l.strip.size == 0 ? l : l[min_start_spaces .. -1] }
end
# Select lines according to labels in code. Currently we use "$example on$" and "$example off$"
# as labels. Note that code blocks identified by the labels should not overlap.
def select_lines(code)
lines = code.each_line.to_a
# Select the array of start labels from code.
startIndices = lines
.each_with_index
.select { |l, i| l.include? "$example on#{@snippet_label}$" }
.map { |l, i| i }
# Select the array of end labels from code.
endIndices = lines
.each_with_index
.select { |l, i| l.include? "$example off#{@snippet_label}$" }
.map { |l, i| i }
raise "Start indices amount is not equal to end indices amount, see #{@file}." \
unless startIndices.size == endIndices.size
raise "No code is selected by include_example, see #{@file}." \
if startIndices.size == 0
# Select and join code blocks together, with a space line between each of two continuous
# blocks.
lastIndex = -1
result = ""
startIndices.zip(endIndices).each do |start, endline|
raise "Overlapping between two example code blocks are not allowed, see #{@file}." \
if start <= lastIndex
raise "$example on$ should not be in the same line with $example off$, see #{@file}." \
if start == endline
lastIndex = endline
range = Range.new(start + 1, endline - 1)
trimmed = trim_codeblock(lines[range])
# Filter out possible example tags of overlapped labels.
taggs_filtered = trimmed.select { |l| !l.include? '$example ' }
result += taggs_filtered.join
result += "\n"
end
result
end
end
end
Liquid::Template.register_tag('include_example', Jekyll::IncludeExampleTag)
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