mmaped_file.rb in prometheus-client-mmap-0.7.0.beta17

- old
+ new

@@ -3,10 +3,50 @@
 
 module Prometheus
   module Client
     module Helper
       class MmapedFile < Mmap
+        class << self
+          def open_readonly(filepath)
+            MmapedFile.new(filepath, 'r', Mmap::MAP_PRIVATE)
+          end
+
+          def open(filepath)
+            MmapedFile.new(filepath, 'rw', Mmap::MAP_SHARED)
+          end
+
+          def lock_to_process(filepath)
+            m = open(filepath)
+            if m.lock_to_process
+              Kernel.at_exit do
+                open(filepath).unlock
+              end
+              true
+            else
+              false
+            end
+          ensure
+            m.close
+          end
+
+          def ensure_process_exclusive_file(file_prefix = 'mmaped_file')
+            path = nil
+            filename_number = 0
+            until path && Helper::MmapedFile.lock_to_process(path)
+              filename = "#{file_prefix}_#{Prometheus::Client.pid}-#{filename_number}.db"
+              path = File.join(Prometheus::Client.configuration.multiprocess_files_dir, filename)
+              filename_number += 1
+            end
+            path
+          end
+
+          def open_process_exclusive_file(file_prefix = 'mmaped_file')
+            filename = Helper::MmapedFile.ensure_process_exclusive_file(file_prefix)
+            open(filename)
+          end
+        end
+
         MINIMUM_SIZE = 8
         attr_reader :filepath, :size
 
         def initialize(filepath, mode = 'r', protection = Mmap::MAP_SHARED, options = {})
           @filepath = filepath
@@ -34,11 +74,11 @@
         def used=(value)
           self[4..7] = [value].pack('l')
         end
 
         def locked_to_process?
-          pid > 0
+          pid > 0 && pid_alive?(pid)
         end
 
         def lock_owner?
           pid == Process.pid
         end
@@ -106,46 +146,17 @@
 
         def close
           munmap
         end
 
-        class << self
-          def open_readonly(filepath)
-            MmapedFile.new(filepath, 'r', Mmap::MAP_PRIVATE)
-          end
+        private
 
-          def open(filepath)
-            MmapedFile.new(filepath, 'rw', Mmap::MAP_SHARED)
-          end
-
-          def lock_to_process(filepath)
-            m = open(filepath)
-            if m.lock_to_process
-              Kernel.at_exit do
-                open(filepath).unlock
-              end
-              true
-            else
-              false
-            end
-          ensure
-            m.close
-          end
-
-          def ensure_process_exclusive_file(file_prefix = 'mmaped_file')
-            path = nil
-            filename_number = 0
-            until path && Helper::MmapedFile.lock_to_process(path)
-              filename = "#{file_prefix}_#{Prometheus::Client.pid}-#{filename_number}.db"
-              path = File.join(Prometheus::Client.configuration.multiprocess_files_dir, filename)
-              filename_number += 1
-            end
-            path
-          end
-
-          def open_process_exclusive_file(file_prefix = 'mmaped_file')
-            filename = Helper::MmapedFile.ensure_process_exclusive_file(file_prefix)
-            open(filename)
+        def pid_alive?(pid)
+          begin
+            Process.getpgid(pid)
+            true
+          rescue Errno::ESRCH
+            false
           end
         end
       end
     end
   end