FEATURE: ability to hide or show specific post revisions

app/assets/javascripts/discourse/controllers/history.js.es6

@@ -25,6 +25,20 @@ export default ObjectController.extend(ModalFunctionality, {
     });
   },
 
+  hide: function(postId, postVersion) {
+    var self = this;
+    Discourse.Post.hideRevision(postId, postVersion).then(function (result) {
+      self.refresh(postId, postVersion);
+    });
+  },
+
+  show: function(postId, postVersion) {
+    var self = this;
+    Discourse.Post.showRevision(postId, postVersion).then(function (result) {
+      self.refresh(postId, postVersion);
+    });
+  },
+
   createdAtDate: function() { return moment(this.get("created_at")).format("LLLL"); }.property("created_at"),
 
   previousVersion: function() { return this.get("version") - 1; }.property("version"),
@@ -35,6 +49,9 @@ export default ObjectController.extend(ModalFunctionality, {
   displayGoToNext: function() { return this.get("version") < this.get("revisions_count"); }.property("version", "revisions_count"),
   displayGoToLast: function() { return this.get("version") < this.get("revisions_count") - 1; }.property("version", "revisions_count"),
 
+  displayShow: function() { return this.get("hidden") && Discourse.User.currentProp('staff'); }.property("hidden"),
+  displayHide: function() { return !this.get("hidden") && Discourse.User.currentProp('staff'); }.property("hidden"),
+
   displayingInline: Em.computed.equal("viewMode", "inline"),
   displayingSideBySide: Em.computed.equal("viewMode", "side_by_side"),
   displayingSideBySideMarkdown: Em.computed.equal("viewMode", "side_by_side_markdown"),
@@ -118,6 +135,9 @@ export default ObjectController.extend(ModalFunctionality, {
     loadNextVersion: function() { this.refresh(this.get("post_id"), this.get("version") + 1); },
     loadLastVersion: function() { this.refresh(this.get("post_id"), this.get("revisions_count")); },
 
+    hideVersion: function() { this.hide(this.get("post_id"), this.get("version")); },
+    showVersion: function() { this.show(this.get("post_id"), this.get("version")); },
+
     displayInline: function() { this.set("viewMode", "inline"); },
     displaySideBySide: function() { this.set("viewMode", "side_by_side"); },
     displaySideBySideMarkdown: function() { this.set("viewMode", "side_by_side_markdown"); }

app/assets/javascripts/discourse/models/_post.js

@@ -471,6 +471,14 @@ Discourse.Post.reopenClass({
     });
   },
 
+  hideRevision: function(postId, version) {
+    return Discourse.ajax("/posts/" + postId + "/revisions/" + version + "/hide", { type: 'PUT' });
+  },
+
+  showRevision: function(postId, version) {
+    return Discourse.ajax("/posts/" + postId + "/revisions/" + version + "/show", { type: 'PUT' });
+  },
+
   loadQuote: function(postId) {
     return Discourse.ajax("/posts/" + postId + ".json").then(function (result) {
       var post = Discourse.Post.create(result);

app/assets/javascripts/discourse/templates/modal/history.hbs

@@ -6,6 +6,12 @@
       <div id="revision-numbers" {{bind-attr class="displayRevisions::invisible"}}>{{{boundI18n revisionsTextKey previousBinding="previousVersion" currentBinding="version" totalBinding="revisions_count"}}}</div>
       <button title="{{i18n post.revisions.controls.next}}" {{bind-attr class=":btn :standard displayGoToNext::invisible" disabled=loading}} {{action "loadNextVersion"}}><i class="fa fa-forward"></i></button>
       <button title="{{i18n post.revisions.controls.last}}" {{bind-attr class=":btn :standard displayGoToLast::invisible" disabled=loading}} {{action "loadLastVersion"}}><i class="fa fa-fast-forward"></i></button>
+      {{#if displayHide}}
+        <button title="{{i18n post.revisions.controls.hide}}" {{bind-attr class=":btn :standard" disabled=loading}} {{action "hideVersion"}}><i class="fa fa-trash-o"></i></button>
+      {{/if}}
+      {{#if displayShow}}
+        <button title="{{i18n post.revisions.controls.show}}" {{bind-attr class=":btn :standard" disabled=loading}} {{action "showVersion"}}><i class="fa fa-undo"></i></button>
+      {{/if}}
     </div>
     {{#if loading}}<div id='revision-loading'><i class='fa fa-spinner fa-spin'></i>{{i18n loading}}</div>{{/if}}
     <div id="display-modes">

app/controllers/posts_controller.rb

@@ -216,6 +216,20 @@ class PostsController < ApplicationController
     render_json_dump(post_revision_serializer)
   end
 
+  def hide_revision
+    post_revision = find_post_revision_from_params
+    guardian.ensure_can_hide_post_revision! post_revision
+    post_revision.hide!
+    render nothing: true
+  end
+
+  def show_revision
+    post_revision = find_post_revision_from_params
+    guardian.ensure_can_show_post_revision! post_revision
+    post_revision.show!
+    render nothing: true
+  end
+
   def bookmark
     post = find_post_from_params
     if current_user

app/models/post_revision.rb

@@ -29,8 +29,8 @@ class PostRevision < ActiveRecord::Base
   end
 
   def wiki_changes
-    prev = lookup("wiki", 0)
-    cur = lookup("wiki", 1)
+    prev = previous("wiki")
+    cur = current("wiki")
     return if prev == cur
 
     {
@@ -40,8 +40,8 @@ class PostRevision < ActiveRecord::Base
   end
 
   def post_type_changes
-    prev = lookup("post_type", 0)
-    cur = lookup("post_type", 1)
+    prev = previous("post_type")
+    cur = current("post_type")
     return if prev == cur
 
     {
@@ -75,48 +75,96 @@ class PostRevision < ActiveRecord::Base
   end
 
   def previous(field)
-    lookup_with_fallback(field, 0)
+    val = lookup(field)
+    if val.nil?
+      val = lookup_in_previous_revisions(field)
+    end
+
+    if val.nil?
+      val = lookup_in_post(field)
+    end
+
+    val
   end
 
   def current(field)
-    lookup_with_fallback(field, 1)
+    val = lookup_in_next_revision(field)
+    if val.nil?
+      val = lookup_in_post(field)
+    end
+
+    if val.nil?
+      val = lookup(field)
+    end
+
+    if val.nil?
+      val = lookup_in_previous_revisions(field)
+    end
+
+    return val
   end
 
   def previous_revisions
-    @previous_revs ||= PostRevision.where("post_id = ? AND number < ?", post_id, number)
+    @previous_revs ||= PostRevision.where("post_id = ? AND number < ? AND hidden = ?", post_id, number, false)
                                    .order("number desc")
                                    .to_a
   end
 
+  def next_revision
+    @next_revision ||= PostRevision.where("post_id = ? AND number > ? AND hidden = ?", post_id, number, false)
+                                   .order("number asc")
+                                   .to_a.first
+  end
+
   def has_topic_data?
     post && post.post_number == 1
   end
 
-  def lookup_with_fallback(field, index)
-
-    unless val = lookup(field, index)
-      previous_revisions.each do |v|
-        break if val = v.lookup(field, 1)
-      end
+  def lookup_in_previous_revisions(field)
+    previous_revisions.each do |v|
+      val = v.lookup(field)
+      return val unless val.nil?
     end
 
-    unless val
-      if ["cooked", "raw"].include?(field)
-        val = post.send(field)
-      else
-        val = post.topic.send(field)
-      end
+    nil
+  end
+
+  def lookup_in_next_revision(field)
+    if next_revision
+      return next_revision.lookup(field)
+    end
+  end
+
+  def lookup_in_post(field)
+    if !post
+      return
+    elsif ["cooked", "raw"].include?(field)
+      val = post.send(field)
+    elsif ["title", "category_id"].include?(field)
+      val = post.topic.send(field)
     end
 
     val
   end
 
-  def lookup(field, index)
-    if mod = modifications[field]
-      mod[index]
+  def lookup(field)
+    return nil if hidden
+    mod = modifications[field]
+    unless mod.nil?
+      mod[0]
     end
   end
 
+  def hide!
+    self.hidden = true
+    self.save!
+  end
+
+  def show!
+    self.hidden = false
+    self.save!
+  end
+
 end
 
 # == Schema Information

app/serializers/post_revision_serializer.rb

@@ -12,7 +12,8 @@ class PostRevisionSerializer < ApplicationSerializer
              :category_changes,
              :user_changes,
              :wiki_changes,
-             :post_type_changes
+             :post_type_changes,
+             :hidden
 
   def include_title_changes?
     object.has_topic_data?
@@ -22,6 +23,10 @@ class PostRevisionSerializer < ApplicationSerializer
     object.has_topic_data?
   end
 
+  def hidden
+    object.hidden
+  end
+
   def version
     object.number
   end
@@ -43,7 +48,7 @@ class PostRevisionSerializer < ApplicationSerializer
   end
 
   def edit_reason
-    object.lookup("edit_reason", 1)
+    object.current("edit_reason")
   end
 
   def user_changes