Use LockFile instead of Hbc::Utils::file_locked?.

Library/Homebrew/cask/lib/hbc/cli/cleanup.rb

@@ -75,14 +75,18 @@ module Hbc
         paths.each do |item|
           next unless item.exist?
           processed_files += 1
-          if Utils.file_locked?(item)
+
+          begin
+            LockFile.new(item.basename).with_lock do
+              puts item
+              item_size = File.size?(item)
+              cleanup_size += item_size unless item_size.nil?
+              item.unlink
+            end
+          rescue OperationInProgressError
             puts "skipping: #{item} is locked"
             next
           end
-          puts item
-          item_size = File.size?(item)
-          cleanup_size += item_size unless item_size.nil?
-          item.unlink
         end
 
         if processed_files.zero?

Library/Homebrew/cask/lib/hbc/download_strategy.rb

@@ -82,10 +82,16 @@ module Hbc
     end
 
     def clear_cache
-      [cached_location, temporary_path].each do |f|
-        next unless f.exist?
-        raise CurlDownloadStrategyError, "#{f} is in use by another process" if Utils.file_locked?(f)
-        f.unlink
+      [cached_location, temporary_path].each do |path|
+        next unless path.exist?
+
+        begin
+          LockFile.new(path.basename).with_lock do
+            path.unlink
+          end
+        rescue OperationInProgressError
+          raise CurlDownloadStrategyError, "#{path} is in use by another process"
+        end
       end
     end
 
@@ -105,10 +111,8 @@ module Hbc
       else
         had_incomplete_download = temporary_path.exist?
         begin
-          File.open(temporary_path, "a+") do |f|
-            f.flock(File::LOCK_EX)
+          LockFile.new(temporary_path.basename).with_lock do
             _fetch
-            f.flock(File::LOCK_UN)
           end
         rescue ErrorDuringExecution
           # 33 == range not supported

Library/Homebrew/cask/lib/hbc/utils.rb

@@ -2,8 +2,6 @@ require "yaml"
 require "open3"
 require "stringio"
 
-require "hbc/utils/file"
-
 BUG_REPORTS_URL = "https://github.com/caskroom/homebrew-cask#reporting-bugs".freeze
 
 # monkeypatch Object - not a great idea

Library/Homebrew/cask/lib/hbc/utils/file.rb

@@ -1,14 +0,0 @@
-module Hbc
-  module Utils
-    module_function
-
-    def file_locked?(file)
-      unlocked = File.open(file).flock(File::LOCK_EX | File::LOCK_NB)
-      # revert lock if file was unlocked before check
-      File.open(file).flock(File::LOCK_UN) if unlocked
-      !unlocked
-    rescue
-      true
-    end
-  end
-end

Library/Homebrew/lock_file.rb

@@ -2,7 +2,7 @@ require "fcntl"
 
 class LockFile
   def initialize(name)
-    @name = name
+    @name = name.to_s
     @path = HOMEBREW_LOCK_DIR/"#{@name}.lock"
     @lockfile = nil
   end