Make Sitemap::Store more thread-safe.

middleman-core/lib/middleman-core/sitemap/store.rb

@@ -1,5 +1,6 @@
 # Used for merging results of metadata callbacks
 require "active_support/core_ext/hash/deep_merge"
+require 'monitor'
 
 module Middleman
 
@@ -25,6 +26,8 @@ module Middleman
         @_cached_metadata = {}
         @resource_list_manipulators = []
         @needs_sitemap_rebuild = true
+        @lock = Monitor.new
+
         reset_lookup_cache!
 
         # Register classes which can manipulate the main site map list
@@ -48,31 +51,38 @@ module Middleman
       # Rebuild the list of resources from scratch, using registed manipulators
       # @return [void]
       def rebuild_resource_list!(reason=nil)
+        @lock.synchronize do
           @needs_sitemap_rebuild = true
         end
+      end
 
       # Find a resource given its original path
       # @param [String] request_path The original path of a resource.
       # @return [Middleman::Sitemap::Resource]
       def find_resource_by_path(request_path)
+        @lock.synchronize do
           request_path = ::Middleman::Util.normalize_path(request_path)
           ensure_resource_list_updated!
           @_lookup_by_path[request_path]
         end
+      end
 
       # Find a resource given its destination path
       # @param [String] request_path The destination (output) path of a resource.
       # @return [Middleman::Sitemap::Resource]
       def find_resource_by_destination_path(request_path)
+        @lock.synchronize do
           request_path = ::Middleman::Util.normalize_path(request_path)
           ensure_resource_list_updated!
           @_lookup_by_destination_path[request_path]
         end
+      end
 
       # Get the array of all resources
       # @param [Boolean] include_ignored Whether to include ignored resources
       # @return [Array<Middleman::Sitemap::Resource>]
       def resources(include_ignored=false)
+        @lock.synchronize do
           ensure_resource_list_updated!
           if include_ignored
             @resources
@@ -80,6 +90,7 @@ module Middleman
             @resources.reject(&:ignored?)
           end
         end
+      end
 
       # Register a handler to provide metadata on a file path
       # @param [Regexp] matcher
@@ -201,6 +212,7 @@ module Middleman
       # rebuild_resource_list! since the last time it was run. This is
       # very expensive!
       def ensure_resource_list_updated!
+        @lock.synchronize do
           return unless @needs_sitemap_rebuild
           @needs_sitemap_rebuild = false
 
@@ -219,12 +231,15 @@ module Middleman
             newres
           end
         end
+      end
 
       private
 
       def reset_lookup_cache!
+        @lock.synchronize {
           @_lookup_by_path = {}
           @_lookup_by_destination_path = {}
+        }
       end
     end
   end