backport fix for #1791 honor GS environment variable when looking for Ghostscript's gs command

4 files changed, 50 insertions, 15 deletions

diff --git a/CHANGELOG.adoc b/CHANGELOG.adoc
index e49126d5..98ef14e4 100644
--- a/CHANGELOG.adoc
+++ b/CHANGELOG.adoc
@@ -7,6 +7,10 @@ For a detailed view of what has changed, refer to the {uri-repo}/commits/v1.6.x[
 
 == Unreleased
 
+Enhancements::
+
+* allow path of ghostscript command to be controlled using `GS` env var (#1791)
+
 Compliance::
 
 * add support for Ruby 3 and drop support for Ruby < 2.5 and JRuby < 9.2
diff --git a/bin/asciidoctor-pdf-optimize b/bin/asciidoctor-pdf-optimize
index 44376134..d5e86aec 100755
--- a/bin/asciidoctor-pdf-optimize
+++ b/bin/asciidoctor-pdf-optimize
@@ -17,4 +17,4 @@ end
 
 quality = args[0] == '--quality' ? args[1].to_s : ''
 
-(Asciidoctor::PDF::Optimizer.new quality).generate_file filename
+(Asciidoctor::PDF::Optimizer.new quality).optimize_file filename
diff --git a/lib/asciidoctor/pdf/converter.rb b/lib/asciidoctor/pdf/converter.rb
index c53962e4..7617b008 100644
--- a/lib/asciidoctor/pdf/converter.rb
+++ b/lib/asciidoctor/pdf/converter.rb
@@ -368,7 +368,10 @@ module Asciidoctor
         @index = IndexCatalog.new
         # NOTE: we have to init Pdfmark class here while we have reference to the doc
         @pdfmark = (doc.attr? 'pdfmark') ? (Pdfmark.new doc) : nil
-        @optimize = doc.attr 'optimize'
+        # NOTE: defer instantiating optimizer until we know min pdf version
+        if (@optimize = doc.attr 'optimize')
+          @optimize = nil unless (defined? ::Asciidoctor::PDF::Optimizer) || !(Helpers.require_library OptimizerRequirePath, 'rghost', :warn).nil?
+        end
         init_scratch_prototype
         self
       end
@@ -3584,7 +3587,7 @@ module Asciidoctor
           pdf_doc.render_file target
           # QUESTION restore attributes first?
           @pdfmark&.generate_file target
-          (Optimizer.new @optimize, pdf_doc.min_version).generate_file target if @optimize && ((defined? ::Asciidoctor::PDF::Optimizer) || !(Helpers.require_library OptimizerRequirePath, 'rghost', :warn).nil?)
+          (Optimizer.new @optimize, pdf_doc.min_version).optimize_file target if @optimize && ((defined? ::Asciidoctor::PDF::Optimizer) || !(Helpers.require_library OptimizerRequirePath, 'rghost', :warn).nil?)
         end
         # write scratch document if debug is enabled (or perhaps DEBUG_STEPS env)
         #get_scratch_document.render_file 'scratch.pdf'
diff --git a/lib/asciidoctor/pdf/optimizer.rb b/lib/asciidoctor/pdf/optimizer.rb
index 00e747b6..744f3d3b 100644
--- a/lib/asciidoctor/pdf/optimizer.rb
+++ b/lib/asciidoctor/pdf/optimizer.rb
@@ -2,11 +2,35 @@
 
 require 'pathname'
 require 'rghost'
+require 'rghost/gs_alone'
 require 'tmpdir'
 
+RGhost::GSAlone.prepend (Module.new do
+  WindowsRx = /win|ming/
+
+  def initialize params, debug
+    (@params = params.dup).push(*(@params.pop.split File::PATH_SEPARATOR))
+    @debug = debug
+  end
+
+  def run
+    RGhost::Config.config_platform unless File.exist? RGhost::Config::GS[:path].to_s
+    (cmd = @params.slice 1, @params.length).unshift RGhost::Config::GS[:path].to_s
+    #puts cmd if @debug
+    system(*cmd)
+  end
+end)
+
+RGhost::Engine.prepend (Module.new do
+  def shellescape str
+    str
+  end
+end)
+
 module Asciidoctor
   module PDF
     class Optimizer
+      # see https://www.ghostscript.com/doc/current/VectorDevices.htm#PSPDF_IN for details
       (QUALITY_NAMES = {
         'default' => :default,
         'screen' => :screen,
@@ -15,27 +39,31 @@ module Asciidoctor
         'prepress' => :prepress,
       }).default = :default
 
+      attr_reader :quality
+      attr_reader :compatibility_level
+
       def initialize quality = 'default', compatibility_level = '1.4'
         @quality = QUALITY_NAMES[quality]
         @compatibility_level = compatibility_level
+        if (gs_path = ::ENV['GS'])
+          ::RGhost::Config::GS[:path] = gs_path
+        end
       end
 
-      def generate_file target
+      def optimize_file target
         ::Dir::Tmpname.create ['asciidoctor-pdf-', '.pdf'] do |tmpfile|
-          filename = Pathname.new target
-          filename_o = Pathname.new tmpfile
-          pdfmark = filename.sub_ext '.pdfmark'
-          inputs = pdfmark.file? ? [target, pdfmark.to_s] : target
+          filename_o = ::Pathname.new target
+          filename_tmp = ::Pathname.new tmpfile
+          if (pdfmark = filename_o.sub_ext '.pdfmark').file?
+            inputs = [target, pdfmark.to_s].join ::File::PATH_SEPARATOR
+          else
+            inputs = target
+          end
           (::RGhost::Convert.new inputs).to :pdf,
-              filename: filename_o.to_s,
+              filename: filename_tmp.to_s,
               quality: @quality,
               d: { Printed: false, CannotEmbedFontPolicy: '/Warning', CompatibilityLevel: @compatibility_level }
-          begin
-            filename_o.rename target
-          rescue ::Errno::EXDEV
-            filename.binwrite filename_o.binread
-            filename_o.unlink
-          end
+          filename_o.binwrite filename_tmp.binread
         end
         nil
       end