posts/show: refactor parent/child notices.

* Convert notices from helpers to partials.
* Eliminate PostSets::PostRelationship class in favor of post_sets/posts template.
* Eliminate COUNT(*) queries when calculating the number of child posts.
* Eliminate redundant parent load and parent exists queries.

app/controllers/posts_controller.rb

@@ -27,8 +27,11 @@ class PostsController < ApplicationController
     @comments = @comments.visible(CurrentUser.user)
 
     include_deleted = @post.is_deleted? || (@post.parent_id.present? && @post.parent.is_deleted?) || CurrentUser.user.show_deleted_children?
-    @parent_post_set = PostSets::PostRelationship.new(@post.parent_id, :include_deleted => include_deleted)
+    @sibling_posts = @post.parent.present? ? @post.parent.children : Post.none
-    @children_post_set = PostSets::PostRelationship.new(@post.id, :include_deleted => include_deleted)
+    @sibling_posts = @sibling_posts.undeleted unless include_deleted
+
+    @child_posts = @post.children
+    @child_posts = @child_posts.undeleted unless include_deleted
 
     respond_with(@post) do |format|
       format.html.tooltip { render layout: false }

app/helpers/posts_helper.rb

@@ -1,4 +1,10 @@
 module PostsHelper
+  def post_previews_html(posts, **options)
+    posts.map do |post|
+      PostPresenter.preview(post, **options)
+    end.join("").html_safe
+  end
+
   def post_search_counts_enabled?
     Danbooru.config.enable_post_search_counts && Danbooru.config.reportbooru_server.present? && Danbooru.config.reportbooru_key.present?
   end
@@ -63,45 +69,6 @@ module PostsHelper
     post.favorited_users.reverse_each.map {|user| link_to_user(user)}.join(", ").html_safe
   end
 
-  def has_parent_message(post, parent_post_set)
-    html = ""
-
-    html << "This post belongs to a "
-    html << link_to("parent", posts_path(:tags => "parent:#{post.parent_id}"))
-    html << " (deleted)" if parent_post_set.parent.first.is_deleted?
-
-    sibling_count = parent_post_set.children.count - 1
-    if sibling_count > 0
-      html << " and has "
-      text = (sibling_count == 1) ? "a sibling" : "#{sibling_count} siblings"
-      html << link_to(text, posts_path(:tags => "parent:#{post.parent_id}"))
-    end
-
-    html << " (#{link_to_wiki "learn more", "help:post_relationships"}) "
-
-    html << link_to("&laquo; hide".html_safe, "#", :id => "has-parent-relationship-preview-link")
-
-    html.html_safe
-  end
-
-  def has_children_message(post, children_post_set)
-    html = ""
-
-    html << "This post has "
-    text = (children_post_set.children.count == 1) ? "a child" : "#{children_post_set.children.count} children"
-    html << link_to(text, posts_path(:tags => "parent:#{post.id}"))
-
-    html << " (#{link_to_wiki "learn more", "help:post_relationships"}) "
-
-    html << link_to("&laquo; hide".html_safe, "#", :id => "has-children-relationship-preview-link")
-
-    html.html_safe
-  end
-
-  def pool_link(pool)
-    render("posts/partials/show/pool_link", post: @post, pool: pool)
-  end
-
   def is_pool_selected?(pool)
     return false if params.key?(:q)
     return false if params.key?(:favgroup_id)

app/logical/post_sets/post_relationship.rb

@@ -1,24 +0,0 @@
-module PostSets
-  class PostRelationship < PostSets::Post
-    attr_reader :parent, :children
-
-    def initialize(parent_id, options = {})
-      @parent = ::Post.where("id = ?", parent_id)
-      @children = ::Post.where("parent_id = ?", parent_id).order("id ASC")
-      if options[:include_deleted]
-        super("parent:#{parent_id} status:any")
-      else
-        @children = @children.where("is_deleted = ?", false)
-        super("parent:#{parent_id}")
-      end
-    end
-
-    def posts
-      @parent + @children
-    end
-
-    def presenter
-      ::PostSetPresenters::Post.new(self)
-    end
-  end
-end

app/models/post.rb

@@ -1239,10 +1239,6 @@ class Post < ApplicationRecord
       end
     end
 
-    def parent_exists?
-      Post.exists?(parent_id)
-    end
-
     def has_visible_children?
       return true if has_active_children?
       return true if has_children? && CurrentUser.user.show_deleted_children?

app/views/posts/partials/show/_child_notice.html.erb

@@ -0,0 +1,8 @@
+This post has <%= link_to pluralize(children.length, "child"), posts_path(tags: "parent:#{parent.id}") %>
+
+(<%= link_to_wiki "learn more", "help:post_relationships" %>)
+<%= link_to("« hide", "#", id: "has-children-relationship-preview-link") %>
+
+<div id="has-children-relationship-preview">
+  <%= post_previews_html([parent, *children], tags: "parent:#{parent.id}", show_deleted: true) %>
+</div>

app/views/posts/partials/show/_notices.html.erb

@@ -55,17 +55,15 @@
   </div>
 <% end %>
 
-<% if post.parent_id && post.parent_exists? %>
+<% if post.parent.present? %>
   <div class="notice notice-small post-notice post-notice-child">
-    <%= has_parent_message(post, @parent_post_set) %>
+    <%= render "posts/partials/show/parent_notice", parent: post.parent, children: @sibling_posts.to_a %>
-    <div id="has-parent-relationship-preview"><%= @parent_post_set.presenter.post_previews_html(self) %></div>
   </div>
 <% end %>
 
 <% if post.has_visible_children? %>
   <div class="notice notice-small post-notice post-notice-parent">
-    <%= has_children_message(post, @children_post_set) %>
+    <%= render "posts/partials/show/child_notice", parent: post, children: @child_posts.to_a %>
-    <div id="has-children-relationship-preview"><%= @children_post_set.presenter.post_previews_html(self) %></div>
   </div>
 <% end %>
 

app/views/posts/partials/show/_parent_notice.html.erb

@@ -0,0 +1,14 @@
+This post belongs to a <%= link_to "parent", posts_path(tags: "parent:#{parent.id}") %> <% "(deleted)" if parent.is_deleted? %>
+
+<% children.length.tap do |children_count| %>
+  <% if children_count > 1 %>
+    and has <%= link_to pluralize(children_count - 1, "sibling"), posts_path(tags: "parent:#{parent.id}") %>
+  <% end %>
+<% end %>
+
+(<%= link_to_wiki "learn more", "help:post_relationships" %>)
+<%= link_to "« hide", "#", id: "has-parent-relationship-preview-link" %>
+
+<div id="has-parent-relationship-preview">
+  <%= post_previews_html([parent, *children], tags: "parent:#{parent.id}", show_deleted: true) %>
+</div>