Define profiling feature

- Implement a Profiler class which measures performance with RubyProf
  and stdlib's Benchmark.
- Add --profile CLI option which enables the profiler.

lib/iev.rb

@@ -3,10 +3,12 @@
 
 # frozen_string_literal: true
 
+require "benchmark"
 require "creek"
 require "mathml2asciimath"
 require "relaton"
 require "relaton_bib"
+require "ruby-prof"
 require "sequel"
 require "thor"
 require "yaml"

lib/iev/termbase/cli/command.rb

@@ -82,6 +82,12 @@ def self.shared_option(name, methods:, **kwargs)
         type: :boolean,
         default: false,
         methods: %i[xlsx2yaml db2yaml]
+
+      shared_option :profile,
+        desc: "Generates profiler reports for this program, requires ruby-prof",
+        type: :boolean,
+        default: false,
+        methods: %i[xlsx2yaml xlsx2db db2yaml]
     end
   end
 end

lib/iev/termbase/cli/command_helper.rb

@@ -46,6 +46,7 @@ def collection_file_path(file, output_dir)
       # Assigns some global variables accordingly, so these settings are
       # available throughout the program.
       def handle_generic_options(options)
+        $TERMBASE_PROFILE = options[:profile]
         $TERMBASE_PROGRESS = options.fetch(:progress, !ENV["CI"])
         $TERMBASE_DEBUG_TERM_ATTRIBUTES = options[:debug_term_attributes]
       end

lib/iev/termbase/profiler.rb

@@ -0,0 +1,67 @@
+# frozen_string_literal: true
+
+# (c) Copyright 2020 Ribose Inc.
+#
+
+module IEV
+  module Termbase
+    class Profiler
+      attr_reader :bench, :dir, :prefix, :profile
+
+      def self.measure(prefix = nil, &block)
+        new(prefix).run(&block)
+      end
+
+      def initialize(prefix, dir: "profile")
+        @prefix = prefix
+        @dir = dir
+      end
+
+      def run(&block)
+        profiler_enabled? ? run!(&block) : block.call
+      end
+
+      def run!(&block)
+        retval = nil
+        @profile = RubyProf.profile do
+          @bench = Benchmark.measure do
+            retval = block.call
+          end
+        end
+        retval
+      ensure
+        print_reports
+      end
+
+      def profiler_enabled?
+        $TERMBASE_PROFILE
+      end
+
+      private
+
+      def print_reports
+        FileUtils.mkdir_p(dir)
+        print_benchmark("bench.txt")
+        print_profile("flat.txt", RubyProf::FlatPrinter)
+        print_profile("graph.html", RubyProf::GraphHtmlPrinter)
+        print_profile("calls.html", RubyProf::CallStackPrinter)
+      end
+
+      def print_benchmark(suffix)
+        contents = [Benchmark::CAPTION, bench.to_s].join("\n")
+        File.write(report_file_name(suffix), contents)
+      end
+
+      def print_profile(suffix, printer)
+        File.open(report_file_name(suffix), "w") do |file|
+          printer.new(profile).print(file)
+        end
+      end
+
+      def report_file_name(suffix)
+        base_name = [prefix, suffix].compact.join("-")
+        File.expand_path(base_name, dir)
+      end
+    end
+  end
+end