(MODULES-4976) Add windows escaping functions

The shell_escape function is not usable on windows where batch files and
powershell scripts use different escape rules.

Add two functions to escape strings on windots for batch (batch_escape)
and powershell (powershell_escape).

Author: smortex

lib/puppet/parser/functions/batch_escape.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+#
+# batch_escape.rb
+#
+module Puppet::Parser::Functions
+  newfunction(:batch_escape, type: :rvalue, doc: <<-DOC
+    @summary
+      Escapes a string so that it can be safely used in a batch shell command line.
+
+    @return
+      A string of characters with special characters converted to their escaped form.
+
+    >* Note:* that the resulting string should be used unquoted and is not intended for use in double quotes nor in single
+    quotes.
+  DOC
+  ) do |arguments|
+    raise(Puppet::ParseError, "batch_escape(): Wrong number of arguments given (#{arguments.size} for 1)") if arguments.size != 1
+
+    string = arguments[0].to_s
+
+    result = ''
+
+    string.chars.each do |char|
+      result += case char
+                when '"' then '""'
+                when '$', '\\' then "\\#{char}"
+                else char
+                end
+    end
+
+    return %("#{result}")
+  end
+end
+
+# vim: set ts=2 sw=2 et :

lib/puppet/parser/functions/powershell_escape.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+#
+# powershell_escape.rb
+#
+module Puppet::Parser::Functions
+  newfunction(:powershell_escape, type: :rvalue, doc: <<-DOC
+    @summary
+      Escapes a string so that it can be safely used in a PowerShell command line.
+
+    @return
+      A string of characters with special characters converted to their escaped form.
+
+    >* Note:* that the resulting string should be used unquoted and is not intended for use in double quotes nor in single
+    quotes.
+  DOC
+  ) do |arguments|
+    raise(Puppet::ParseError, "shell_escape(): Wrong number of arguments given (#{arguments.size} for 1)") if arguments.size != 1
+
+    string = arguments[0].to_s
+
+    result = ''
+
+    string.chars.each do |char|
+      result += case char
+                when ' ', "'", '`', '|', "\n", '$' then "`#{char}"
+                when '"' then '\`"'
+                else char
+                end
+    end
+
+    return result
+  end
+end
+
+# vim: set ts=2 sw=2 et :

spec/functions/batch_escape_spec.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe 'batch_escape' do
+  it { is_expected.not_to eq(nil) }
+
+  describe 'signature validation' do
+    it { is_expected.to run.with_params.and_raise_error(Puppet::ParseError, %r{wrong number of arguments}i) }
+    it { is_expected.to run.with_params('foo', 'bar').and_raise_error(Puppet::ParseError, %r{wrong number of arguments}i) }
+  end
+
+  describe 'stringification' do
+    it { is_expected.to run.with_params(10).and_return('"10"') }
+    it { is_expected.to run.with_params(false).and_return('"false"') }
+  end
+
+  describe 'escaping' do
+    it { is_expected.to run.with_params('foo').and_return('"foo"') }
+    it { is_expected.to run.with_params('foo bar').and_return('"foo bar"') }
+    it {
+      is_expected.to run.with_params('~`!@#$%^&*()_-=[]\{}|;\':",./<>?')
+                        .and_return('"~`!@#\\$%^&*()_-=[]\\\{}|;\':"",./<>?"')
+    }
+  end
+end

spec/functions/powershell_escape_spec.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe 'powershell_escape' do
+  it { is_expected.not_to eq(nil) }
+
+  describe 'signature validation' do
+    it { is_expected.to run.with_params.and_raise_error(Puppet::ParseError, %r{wrong number of arguments}i) }
+    it { is_expected.to run.with_params('foo', 'bar').and_raise_error(Puppet::ParseError, %r{wrong number of arguments}i) }
+  end
+
+  describe 'stringification' do
+    it { is_expected.to run.with_params(10).and_return('10') }
+    it { is_expected.to run.with_params(false).and_return('false') }
+  end
+
+  describe 'escaping' do
+    it { is_expected.to run.with_params('foo').and_return('foo') }
+    it { is_expected.to run.with_params('foo bar').and_return('foo` bar') }
+    it {
+      is_expected.to run.with_params('~`!@#$%^&*()_-=[]\{}|;\':",./<>?')
+                        .and_return('~``!@#`$%^&*()_-=[]\{}`|;`\':\\`",./<>?')
+    }
+  end
+end