From f48798e85c890c9be6873e427137b8c8cde4171d Mon Sep 17 00:00:00 2001
From: Dmitry Krasnoukhov <dmitry@krasnoukhov.com>
Date: Thu, 7 Nov 2019 16:42:00 +0200
Subject: [PATCH] Memory usage improvements

---
 jsonapi-resources.gemspec           |  1 +
 lib/jsonapi/link_builder.rb         | 23 +++++++++++++----------
 lib/jsonapi/resource.rb             |  7 +++++--
 lib/jsonapi/resource_serializer.rb  |  2 +-
 test/benchmark/request_benchmark.rb |  4 ++--
 test/test_helper.rb                 |  4 ++++
 6 files changed, 26 insertions(+), 15 deletions(-)

diff --git a/jsonapi-resources.gemspec b/jsonapi-resources.gemspec
index 381107ad5..10dfb0aff 100644
--- a/jsonapi-resources.gemspec
+++ b/jsonapi-resources.gemspec
@@ -27,6 +27,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'pry'
   spec.add_development_dependency 'concurrent-ruby-ext'
   spec.add_development_dependency 'database_cleaner'
+  spec.add_development_dependency 'memory_profiler'
   spec.add_dependency 'activerecord', '>= 4.1'
   spec.add_dependency 'railties', '>= 4.1'
   spec.add_dependency 'concurrent-ruby'
diff --git a/lib/jsonapi/link_builder.rb b/lib/jsonapi/link_builder.rb
index 99cd6223c..992e52f77 100644
--- a/lib/jsonapi/link_builder.rb
+++ b/lib/jsonapi/link_builder.rb
@@ -105,16 +105,19 @@ def format_route(route)
     end
 
     def formatted_module_path_from_class(klass)
-      scopes = if @engine
-                 module_scopes_from_class(klass)[1..-1]
-               else
-                 module_scopes_from_class(klass)
-               end
-
-      unless scopes.empty?
-        "/#{ scopes.map {|scope| format_route(scope.to_s.underscore)}.compact.join('/') }/"
-      else
-        "/"
+      @_module_path_cache ||= {}
+      @_module_path_cache[klass] ||= begin
+        scopes = if @engine
+                   module_scopes_from_class(klass)[1..-1]
+                 else
+                   module_scopes_from_class(klass)
+                 end
+
+        unless scopes.empty?
+          "/#{ scopes.map {|scope| format_route(scope.to_s.underscore)}.compact.join('/') }/"
+        else
+          "/"
+        end
       end
     end
 
diff --git a/lib/jsonapi/resource.rb b/lib/jsonapi/resource.rb
index 2f377a67f..84b2a96fb 100644
--- a/lib/jsonapi/resource.rb
+++ b/lib/jsonapi/resource.rb
@@ -5,6 +5,9 @@ module JSONAPI
   class Resource
     include Callbacks
 
+    DEFAULT_ATTRIBUTE_OPTIONS = { format: :default }.freeze
+    MODULE_PATH_REGEXP = /::[^:]+\Z/.freeze
+
     attr_reader :context
 
     define_jsonapi_resources_callbacks :create,
@@ -555,7 +558,7 @@ def attribute(attribute_name, options = {})
       end
 
       def default_attribute_options
-        { format: :default }
+        DEFAULT_ATTRIBUTE_OPTIONS
       end
 
       def relationship(*attrs)
@@ -1133,7 +1136,7 @@ def module_path
         if name == 'JSONAPI::Resource'
           ''
         else
-          name =~ /::[^:]+\Z/ ? ($`.freeze.gsub('::', '/') + '/').underscore : ''
+          name =~ MODULE_PATH_REGEXP ? ($`.freeze.gsub('::', '/') + '/').underscore : ''
         end
       end
 
diff --git a/lib/jsonapi/resource_serializer.rb b/lib/jsonapi/resource_serializer.rb
index 3bdf4dd49..37a573552 100644
--- a/lib/jsonapi/resource_serializer.rb
+++ b/lib/jsonapi/resource_serializer.rb
@@ -287,7 +287,6 @@ def relationships_hash(source, fetchable_fields, include_directives = {})
         include_linkage = ia && ia[:include]
         include_linked_children = ia && !ia[:include_related].empty?
 
-        options = { filters: ia && ia[:include_filters] || {} }
         if field_set.include?(name)
           ro = relationship_object(source, relationship, include_linkage)
           hash[format_key(name)] = ro unless ro.blank?
@@ -300,6 +299,7 @@ def relationships_hash(source, fetchable_fields, include_directives = {})
           resources = if source.preloaded_fragments.has_key?(format_key(name))
             source.preloaded_fragments[format_key(name)].values
           else
+            options = { filters: ia && ia[:include_filters] || {} }
             [source.public_send(name, options)].flatten(1).compact
           end
           resources.each do |resource|
diff --git a/test/benchmark/request_benchmark.rb b/test/benchmark/request_benchmark.rb
index d42d3a695..b71cdf0b5 100644
--- a/test/benchmark/request_benchmark.rb
+++ b/test/benchmark/request_benchmark.rb
@@ -7,7 +7,7 @@ def setup
   end
 
   def bench_large_index_request_uncached
-    10.times do
+    100.times do
       assert_jsonapi_get '/api/v2/books?include=bookComments,bookComments.author'
     end
   end
@@ -15,7 +15,7 @@ def bench_large_index_request_uncached
   def bench_large_index_request_caching
     cache = ActiveSupport::Cache::MemoryStore.new
     with_resource_caching(cache) do
-      10.times do
+      100.times do
         assert_jsonapi_get '/api/v2/books?include=bookComments,bookComments.author'
       end
     end
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 8f8ba5a1f..ee2b36674 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -24,6 +24,7 @@
 require 'minitest/mock'
 require 'jsonapi-resources'
 require 'pry'
+require 'memory_profiler'
 
 require File.expand_path('../helpers/value_matchers', __FILE__)
 require File.expand_path('../helpers/assertions', __FILE__)
@@ -639,6 +640,9 @@ def self.run_one_method(klass, method_name, reporter)
       end
     end
     puts
+    if ENV["MEMORY_PROFILER"]
+      MemoryProfiler.report(allow_files: 'lib/jsonapi') { super(klass, method_name, reporter) }.pretty_print
+    end
   end
 end