refactor: extract CommandLineRunner

Each of the out-of-process parser classes implemented its own
CommandLineRunner, and they were all functionally the same (with some
small differences that weren't actually used). This pulls the class up
to one reused class.

Author: wfleming

lib/cc/engine/analyzers/command_line_runner.rb

@@ -0,0 +1,45 @@
+require "open3"
+require "timeout"
+
+module CC
+  module Engine
+    module Analyzers
+      class CommandLineRunner
+        DEFAULT_TIMEOUT = 20
+
+        def initialize(command, timeout = DEFAULT_TIMEOUT)
+          @command = command
+          @timeout = timeout
+        end
+
+        def run(input)
+          Timeout.timeout(timeout) do
+            Open3.popen3 command, "r+" do |stdin, stdout, stderr, wait_thr|
+              stdin.puts input
+              stdin.close
+
+              exit_code = wait_thr.value
+
+              output = stdout.gets
+              stdout.close
+
+              err_output = stderr.gets
+              stderr.close
+
+              if 0 == exit_code
+                yield output
+              else
+                raise ::CC::Engine::Analyzers::ParserError, "Python parser exited with code #{exit_code}:\n#{err_output}"
+              end
+            end
+          end
+        end
+
+        private
+
+        attr_reader :command, :timeout
+      end
+    end
+  end
+end
+

lib/cc/engine/analyzers/javascript/parser.rb

@@ -1,6 +1,4 @@
-require "open3"
-require "timeout"
-
+require "cc/engine/analyzers/command_line_runner"
 
 module CC
   module Engine
@@ -15,7 +13,7 @@ def initialize(code, filename)
           end
 
           def parse
-            runner = CommandLineRunner.new(js_command, self)
+            runner = CommandLineRunner.new(js_command)
             runner.run(strip_shebang(code)) do |ast|
               json_ast = JSON.parse(ast)
               @syntax_tree = json_ast
@@ -39,45 +37,6 @@ def strip_shebang(code)
             end
           end
         end
-
-        class CommandLineRunner
-          attr_reader :command, :delegate
-
-          DEFAULT_TIMEOUT = 20
-          EXCEPTIONS = [
-            StandardError,
-            Timeout::Error,
-            SystemStackError
-          ]
-
-          def initialize(command, delegate)
-            @command = command
-            @delegate = delegate
-          end
-
-          def run(input, timeout = DEFAULT_TIMEOUT)
-            Timeout.timeout(timeout) do
-              Open3.popen3 command, "r+" do |stdin, stdout, stderr, wait_thr|
-                stdin.puts input
-                stdin.close
-
-                exit_code = wait_thr.value
-
-                output = stdout.gets
-                stdout.close
-
-                err_output = stderr.gets
-                stderr.close
-
-                if 0 == exit_code
-                  yield output
-                else
-                  raise ::CC::Engine::Analyzers::ParserError, "Python parser exited with code #{exit_code}:\n#{err_output}"
-                end
-              end
-            end
-          end
-        end
       end
     end
   end

lib/cc/engine/analyzers/php/parser.rb

@@ -1,5 +1,6 @@
-require 'cc/engine/analyzers/php/ast'
-require 'cc/engine/analyzers/php/nodes'
+require "cc/engine/analyzers/command_line_runner"
+require "cc/engine/analyzers/php/ast"
+require "cc/engine/analyzers/php/nodes"
 
 module CC
   module Engine
@@ -36,39 +37,6 @@ def parser_path
             )
           end
         end
-
-        class CommandLineRunner
-          attr_reader :command, :delegate
-
-          DEFAULT_TIMEOUT = 20
-
-          def initialize(command)
-            @command = command
-          end
-
-          def run(input, timeout = DEFAULT_TIMEOUT)
-            Timeout.timeout(timeout) do
-              Open3.popen3 command, "r+" do |stdin, stdout, stderr, wait_thr|
-                stdin.puts input
-                stdin.close
-
-                exit_code = wait_thr.value
-
-                output = stdout.gets
-                stdout.close
-
-                err_output = stderr.gets
-                stderr.close
-
-                if 0 == exit_code
-                  yield output
-                else
-                  raise ::CC::Engine::Analyzers::ParserError, "Python parser exited with code #{exit_code}:\n#{err_output}"
-                end
-              end
-            end
-          end
-        end
       end
     end
   end

lib/cc/engine/analyzers/python/parser.rb

@@ -1,6 +1,6 @@
+require "cc/engine/analyzers/command_line_runner"
 require "timeout"
 require "json"
-require "open3"
 
 module CC
   module Engine
@@ -15,7 +15,7 @@ def initialize(code, filename)
           end
 
           def parse
-            runner = CommandLineRunner.new(python_command, self)
+            runner = CommandLineRunner.new(python_command)
             runner.run(code) do |ast|
               json_ast = JSON.parse(ast)
               @syntax_tree = json_ast
@@ -29,40 +29,6 @@ def python_command
             "python #{file}"
           end
         end
-
-        class CommandLineRunner
-          DEFAULT_TIMEOUT = 20
-
-          attr_reader :command, :delegate
-
-          def initialize(command, delegate)
-            @command = command
-            @delegate = delegate
-          end
-
-          def run(input, timeout = DEFAULT_TIMEOUT)
-            Timeout.timeout(timeout) do
-              Open3.popen3 command, "r+" do |stdin, stdout, stderr, wait_thr|
-                stdin.puts input
-                stdin.close
-
-                exit_code = wait_thr.value
-
-                output = stdout.gets
-                stdout.close
-
-                err_output = stderr.gets
-                stderr.close
-
-                if 0 == exit_code
-                  yield output
-                else
-                  raise ::CC::Engine::Analyzers::ParserError, "Python parser exited with code #{exit_code}:\n#{err_output}"
-                end
-              end
-            end
-          end
-        end
       end
     end
   end