From 0c07ea043769938653d26b15b123fa784e31fdee Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Sun, 14 Apr 2019 15:26:28 -0400
Subject: [PATCH] compress rscons script like waf - close #76

---
 Rakefile.rb      |  6 +++--
 rb/build_dist.rb | 68 +++++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 65 insertions(+), 9 deletions(-)

diff --git a/Rakefile.rb b/Rakefile.rb
index c03ddb9..b047d5f 100644
--- a/Rakefile.rb
+++ b/Rakefile.rb
@@ -23,16 +23,18 @@ RSpec::Core::RakeTask.new(:spec, :example_string) do |task, args|
     task.rspec_opts = %W[-e "#{args.example_string}" -f documentation]
   end
 end
-
 task :spec => :build_dist
 
+# dspec task is useful to test the distributable release script, but is not
+# useful for coverage information.
 desc "Dist Specs"
-task :dspec, [:example_string] do |task, args|
+task :dspec, [:example_string] => :build_dist do |task, args|
   FileUtils.mkdir_p("test")
   FileUtils.cp("dist/rscons", "test/rscons.rb")
   ENV["dist_specs"] = "1"
   Rake::Task["spec"].invoke(args.example_string)
   ENV.delete("dist_specs")
+  FileUtils.rm_f(Dir.glob(".rscons-*"))
 end
 
 YARD::Rake::YardocTask.new do |yard|
diff --git a/rb/build_dist.rb b/rb/build_dist.rb
index cebfeba..a2db88c 100755
--- a/rb/build_dist.rb
+++ b/rb/build_dist.rb
@@ -2,14 +2,25 @@
 
 require "fileutils"
 
+if File.read("lib/rscons/version.rb") =~ /VERSION = "(.+)"/
+  VERSION = $1
+else
+  raise "Could not determine version."
+end
+if `git show | head -n 1` =~ /commit\s+([0-9a-f]{7})/i
+  GIT = $1
+else
+  raise "Could not determine git revision."
+end
 PROG_NAME = "rscons"
 START_FILE = "bin/#{PROG_NAME}"
 LIB_DIR = "lib"
 DIST = "dist"
 
 files_processed = {}
+combined_file = []
 
-process_file = lambda do |file, fh|
+combine_files = lambda do |file|
   File.read(file, mode: "rb").each_line do |line|
     if line =~ /^\s*require(?:_relative)?\s*"(.*)"$/
       require_name = $1
@@ -18,22 +29,65 @@ process_file = lambda do |file, fh|
         if File.exists?(path)
           unless files_processed[path]
             files_processed[path] = true
-            process_file[path, fh]
+            combine_files[path]
           end
         else
           raise "require path #{path.inspect} not found"
         end
       else
-        fh.write(line)
+        combined_file << line
       end
     else
-      fh.write(line)
+      combined_file << line
     end
   end
 end
 
-FileUtils.mkdir_p(DIST)
+combine_files[START_FILE]
 
-File.open("#{DIST}/#{PROG_NAME}", "wb", 0755) do |fh|
-  process_file[START_FILE, fh]
+# Strip Ruby comment lines and empty lines to save some space, but do not
+# remove lines that are in heredoc sections. This isn't terribly robust to be
+# used in the wild, but works for the heredoc instances for this project.
+stripped_comments = []
+heredoc_end = nil
+combined_file.each do |line|
+  if line =~ /<<-?([A-Z]+)/
+    heredoc_end = $1
+  end
+  if heredoc_end and line =~ /^\s*#{heredoc_end}/
+    heredoc_end = nil
+  end
+  if heredoc_end or not (line =~ /^\s*(#[^!].*)?$/)
+    stripped_comments << line
+  end
+end
+
+require "zlib"
+compressed_script = Zlib::Deflate.deflate(stripped_comments.join)
+escaped_compressed_script = compressed_script.gsub("#", "#1").gsub("\n", "#2").gsub("\r", "#3").gsub("\0", "#4")
+
+FileUtils.mkdir_p(DIST)
+File.open("#{DIST}/#{PROG_NAME}", "wb", 0755) do |fh|
+  fh.write(<<EOF)
+#!/usr/bin/env ruby
+script = ".rscons-#{VERSION}-#{GIT}.rb"
+unless File.exists?(script)
+  if File.read(__FILE__, mode: "rb") =~ /^#==>(.*)/
+    escaped_compressed = $1
+    unescaped_compressed = escaped_compressed.gsub("#4", "\\0").gsub("#3", "\\r").gsub("#2", "\\n").gsub("#1", "#")
+    require "zlib"
+    inflated = Zlib::Inflate.inflate(unescaped_compressed)
+    File.open(script, "wb") do |fh|
+      fh.write(inflated)
+    end
+  else
+    raise "Could not decompress."
+  end
+end
+load script
+if __FILE__ == $0
+  Rscons::Cli.run(ARGV)
+end
+#==>#{escaped_compressed_script}
+EOF
 end