Refactor reference gathering to use a dedicated filter

12 files changed, 169 insertions, 89 deletions

diff --git a/lib/gitlab/markdown/commit_range_reference_filter.rb b/lib/gitlab/markdown/commit_range_reference_filter.rb
index bb496135d92..e070edae0a4 100644
--- a/lib/gitlab/markdown/commit_range_reference_filter.rb
+++ b/lib/gitlab/markdown/commit_range_reference_filter.rb
@@ -26,6 +26,18 @@ module Gitlab
         end
       end
 
+      def self.referenced_by(node)
+        project = Project.find(node.attr("data-project")) rescue nil
+        return unless project
+
+        id = node.attr("data-commit-range")
+        range = CommitRange.new(id, project)
+
+        return unless range.valid_commits?
+
+        { commit_range: range }
+      end
+
       def initialize(*args)
         super
 
@@ -53,13 +65,11 @@ module Gitlab
           range = CommitRange.new(id, project)
 
           if range.valid_commits?
-            push_result(:commit_range, range)
-
             url = url_for_commit_range(project, range)
 
             title = range.reference_title
             klass = reference_class(:commit_range)
-            data  = data_attribute(project.id)
+            data  = data_attribute(project: project.id, commit_range: id)
 
             project_ref += '@' if project_ref
 
diff --git a/lib/gitlab/markdown/commit_reference_filter.rb b/lib/gitlab/markdown/commit_reference_filter.rb
index fcbb2e936a5..8cdbeb1f9cf 100644
--- a/lib/gitlab/markdown/commit_reference_filter.rb
+++ b/lib/gitlab/markdown/commit_reference_filter.rb
@@ -26,6 +26,18 @@ module Gitlab
         end
       end
 
+      def self.referenced_by(node)
+        project = Project.find(node.attr("data-project")) rescue nil
+        return unless project
+
+        id = node.attr("data-commit")
+        commit = commit_from_ref(project, id)
+
+        return unless commit
+
+        { commit: commit }
+      end
+
       def call
         replace_text_nodes_matching(Commit.reference_pattern) do |content|
           commit_link_filter(content)
@@ -39,17 +51,15 @@ module Gitlab
       # Returns a String with commit references replaced with links. All links
       # have `gfm` and `gfm-commit` class names attached for styling.
       def commit_link_filter(text)
-        self.class.references_in(text) do |match, commit_ref, project_ref|
+        self.class.references_in(text) do |match, id, project_ref|
           project = self.project_from_ref(project_ref)
 
-          if commit = commit_from_ref(project, commit_ref)
-            push_result(:commit, commit)
-
+          if commit = self.class.commit_from_ref(project, id)
             url = url_for_commit(project, commit)
 
             title = escape_once(commit.link_title)
             klass = reference_class(:commit)
-            data  = data_attribute(project.id)
+            data  = data_attribute(project: project.id, commit: id)
 
             project_ref += '@' if project_ref
 
@@ -62,9 +72,9 @@ module Gitlab
         end
       end
 
-      def commit_from_ref(project, commit_ref)
+      def self.commit_from_ref(project, id)
         if project && project.valid_repo?
-          project.commit(commit_ref)
+          project.commit(id)
         end
       end
 
diff --git a/lib/gitlab/markdown/external_issue_reference_filter.rb b/lib/gitlab/markdown/external_issue_reference_filter.rb
index f7c43e1ca89..8f86f13976a 100644
--- a/lib/gitlab/markdown/external_issue_reference_filter.rb
+++ b/lib/gitlab/markdown/external_issue_reference_filter.rb
@@ -47,8 +47,9 @@ module Gitlab
 
           title = escape_once("Issue in #{project.external_issue_tracker.title}")
           klass = reference_class(:issue)
+          data  = data_attribute(project: project.id)
 
-          %(<a href="#{url}"
+          %(<a href="#{url}" #{data}
                title="#{title}"
                class="#{klass}">#{match}</a>)
         end
diff --git a/lib/gitlab/markdown/issue_reference_filter.rb b/lib/gitlab/markdown/issue_reference_filter.rb
index 01320f80796..cd2a9b75680 100644
--- a/lib/gitlab/markdown/issue_reference_filter.rb
+++ b/lib/gitlab/markdown/issue_reference_filter.rb
@@ -27,6 +27,13 @@ module Gitlab
         end
       end
 
+      def self.referenced_by(node)
+        issue = Issue.find(node.attr("data-issue")) rescue nil
+        return unless issue
+
+        { issue: issue }
+      end
+
       def call
         replace_text_nodes_matching(Issue.reference_pattern) do |content|
           issue_link_filter(content)
@@ -45,13 +52,11 @@ module Gitlab
           project = self.project_from_ref(project_ref)
 
           if project && issue = project.get_issue(id)
-            push_result(:issue, issue)
-
             url = url_for_issue(id, project, only_path: context[:only_path])
 
             title = escape_once("Issue: #{issue.title}")
             klass = reference_class(:issue)
-            data  = data_attribute(project.id)
+            data  = data_attribute(project: project.id, issue: issue.id)
 
             %(<a href="#{url}" #{data}
                  title="#{title}"
diff --git a/lib/gitlab/markdown/label_reference_filter.rb b/lib/gitlab/markdown/label_reference_filter.rb
index 1e5cb12071e..59568ab531f 100644
--- a/lib/gitlab/markdown/label_reference_filter.rb
+++ b/lib/gitlab/markdown/label_reference_filter.rb
@@ -22,6 +22,13 @@ module Gitlab
         end
       end
 
+      def self.referenced_by(node)
+        label = Label.find(node.attr("data-label")) rescue nil
+        return unless label
+
+        { label: label }
+      end
+
       def call
         replace_text_nodes_matching(Label.reference_pattern) do |content|
           label_link_filter(content)
@@ -41,11 +48,9 @@ module Gitlab
           params = label_params(id, name)
 
           if label = project.labels.find_by(params)
-            push_result(:label, label)
-
             url = url_for_label(project, label)
             klass = reference_class(:label)
-            data = data_attribute(project.id)
+            data = data_attribute(project: project.id, label: label.id)
 
             %(<a href="#{url}" #{data}
                  class="#{klass}">#{render_colored_label(label)}</a>)
diff --git a/lib/gitlab/markdown/merge_request_reference_filter.rb b/lib/gitlab/markdown/merge_request_reference_filter.rb
index ecbd263d0e0..440574e574b 100644
--- a/lib/gitlab/markdown/merge_request_reference_filter.rb
+++ b/lib/gitlab/markdown/merge_request_reference_filter.rb
@@ -27,6 +27,13 @@ module Gitlab
         end
       end
 
+      def self.referenced_by(node)
+        merge_request = MergeRequest.find(node.attr("data-merge-request")) rescue nil
+        return unless merge_request
+
+        { merge_request: merge_request }
+      end
+
       def call
         replace_text_nodes_matching(MergeRequest.reference_pattern) do |content|
           merge_request_link_filter(content)
@@ -45,11 +52,9 @@ module Gitlab
           project = self.project_from_ref(project_ref)
 
           if project && merge_request = project.merge_requests.find_by(iid: id)
-            push_result(:merge_request, merge_request)
-
             title = escape_once("Merge Request: #{merge_request.title}")
             klass = reference_class(:merge_request)
-            data  = data_attribute(project.id)
+            data  = data_attribute(project: project.id, merge_request: merge_request.id)
 
             url = url_for_merge_request(merge_request, project)
 
diff --git a/lib/gitlab/markdown/redactor_filter.rb b/lib/gitlab/markdown/redactor_filter.rb
index ae1c3c365bd..07ea6207d22 100644
--- a/lib/gitlab/markdown/redactor_filter.rb
+++ b/lib/gitlab/markdown/redactor_filter.rb
@@ -19,49 +19,19 @@ module Gitlab
         doc
       end
 
+      private
+
       def user_can_reference?(node)
-        if node.has_attribute?('data-group-id')
-          user_can_reference_group?(node.attr('data-group-id'))
-        elsif node.has_attribute?('data-project-id')
-          user_can_reference_project?(node.attr('data-project-id'))
-        elsif node.has_attribute?('data-user-id')
-          user_can_reference_user?(node.attr('data-user-id'))
+        if node.has_attribute?('data-reference-filter')
+          reference_type = node.attr('data-reference-filter')
+          reference_filter = reference_type.constantize
+
+          reference_filter.user_can_reference?(current_user, node)
         else
           true
         end
       end
 
-      def user_can_reference_group?(id)
-        group = Group.find(id)
-
-        group && can?(:read_group, group)
-      rescue ActiveRecord::RecordNotFound
-        false
-      end
-
-      def user_can_reference_project?(id)
-        project = Project.find(id)
-
-        project && can?(:read_project, project)
-      rescue ActiveRecord::RecordNotFound
-        false
-      end
-
-      def user_can_reference_user?(id)
-        # Permit all user reference links
-        true
-      end
-
-      private
-
-      def abilities
-        Ability.abilities
-      end
-
-      def can?(ability, object)
-        abilities.allowed?(current_user, ability, object)
-      end
-
       def current_user
         context[:current_user]
       end
diff --git a/lib/gitlab/markdown/reference_filter.rb b/lib/gitlab/markdown/reference_filter.rb
index 9b293c957d6..ea6136b3303 100644
--- a/lib/gitlab/markdown/reference_filter.rb
+++ b/lib/gitlab/markdown/reference_filter.rb
@@ -15,10 +15,17 @@ module Gitlab
     # Results:
     #   :references - A Hash of references that were found and replaced.
     class ReferenceFilter < HTML::Pipeline::Filter
-      def initialize(*args)
-        super
+      def self.user_can_reference?(user, node)
+        if node.has_attribute?('data-project')
+          project = Project.find(node.attr('data-project')) rescue nil
+          Ability.abilities.allowed?(user, :read_project, project)
+        else
+          true
+        end
+      end
 
-        result[:references] = Hash.new { |hash, type| hash[type] = [] }
+      def self.referenced_by(node)
+        nil
       end
 
       # Returns a data attribute String to attach to a reference link
@@ -28,13 +35,14 @@ module Gitlab
       #
       # Examples:
       #
-      #   data_attribute(1)         # => "data-project-id=\"1\""
-      #   data_attribute(2, :user)  # => "data-user-id=\"2\""
-      #   data_attribute(3, :group) # => "data-group-id=\"3\""
+      #   data_attribute(project: 1)  # => "data-reference-filter=\"SomeReferenceFilter\" data-project=\"1\""
+      #   data_attribute(user: 2)     # => "data-reference-filter=\"SomeReferenceFilter\" data-user=\"2\""
+      #   data_attribute(group: 3)    # => "data-reference-filter=\"SomeReferenceFilter\" data-group=\"3\""
       #
       # Returns a String
-      def data_attribute(id, type = :project)
-        %Q(data-#{type}-id="#{id}")
+      def data_attribute(attributes = {})
+        attributes[:reference_filter] = self.class.name
+        attributes.map { |key, value| %Q(data-#{key.to_s.dasherize}="#{value}") }.join(" ")
       end
 
       def escape_once(html)
@@ -59,16 +67,6 @@ module Gitlab
         context[:project]
       end
 
-      # Add a reference to the pipeline's result Hash
-      #
-      # type   - Singular Symbol reference type (e.g., :issue, :user, etc.)
-      # values - One or more Objects to add
-      def push_result(type, *values)
-        return if values.empty?
-
-        result[:references][type].push(*values)
-      end
-
       def reference_class(type)
         "gfm gfm-#{type}"
       end
diff --git a/lib/gitlab/markdown/reference_gatherer_filter.rb b/lib/gitlab/markdown/reference_gatherer_filter.rb
new file mode 100644
index 00000000000..d64671e9550
--- /dev/null
+++ b/lib/gitlab/markdown/reference_gatherer_filter.rb
@@ -0,0 +1,49 @@
+require 'gitlab/markdown'
+require 'html/pipeline/filter'
+
+module Gitlab
+  module Markdown
+    # HTML filter that removes references to records that the current user does
+    # not have permission to view.
+    #
+    # Expected to be run in its own post-processing pipeline.
+    #
+    class ReferenceGathererFilter < HTML::Pipeline::Filter
+      def initialize(*)
+        super
+
+        result[:references] ||= Hash.new { |hash, type| hash[type] = [] }
+      end
+
+      def call
+        doc.css('a.gfm').each do |node|
+          gather_references(node)
+        end
+
+        doc
+      end
+
+      private
+
+      def gather_references(node)
+        return unless node.has_attribute?('data-reference-filter')
+
+        reference_type = node.attr('data-reference-filter')
+        reference_filter = reference_type.constantize
+
+        return unless reference_filter.user_can_reference?(current_user, node)
+
+        references = reference_filter.referenced_by(node)
+        return unless references
+        
+        references.each do |type, values|
+          result[:references][type].push(*values)
+        end
+      end
+
+      def current_user
+        context[:current_user]
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/markdown/snippet_reference_filter.rb b/lib/gitlab/markdown/snippet_reference_filter.rb
index e2cf89cb1d8..a7396e96529 100644
--- a/lib/gitlab/markdown/snippet_reference_filter.rb
+++ b/lib/gitlab/markdown/snippet_reference_filter.rb
@@ -27,6 +27,13 @@ module Gitlab
         end
       end
 
+      def self.referenced_by(node)
+        snippet = Snippet.find(node.attr("data-snippet")) rescue nil
+        return unless snippet
+
+        { snippet: snippet }
+      end
+
       def call
         replace_text_nodes_matching(Snippet.reference_pattern) do |content|
           snippet_link_filter(content)
@@ -45,11 +52,9 @@ module Gitlab
           project = self.project_from_ref(project_ref)
 
           if project && snippet = project.snippets.find_by(id: id)
-            push_result(:snippet, snippet)
-
             title = escape_once("Snippet: #{snippet.title}")
             klass = reference_class(:snippet)
-            data  = data_attribute(project.id)
+            data  = data_attribute(project: project.id, snippet: snippet.id)
 
             url = url_for_snippet(snippet, project)
 
diff --git a/lib/gitlab/markdown/user_reference_filter.rb b/lib/gitlab/markdown/user_reference_filter.rb
index c08811effb2..0d2be7499b7 100644
--- a/lib/gitlab/markdown/user_reference_filter.rb
+++ b/lib/gitlab/markdown/user_reference_filter.rb
@@ -23,6 +23,34 @@ module Gitlab
         end
       end
 
+      def self.referenced_by(node)
+        if node.has_attribute?('data-group')
+          group = Group.find(node.attr('data-group')) rescue nil
+          return unless group
+
+          { user: group.users }
+        elsif node.has_attribute?('data-user')
+          user = User.find(node.attr('data-user')) rescue nil
+          return unless user
+
+          { user: user }
+        elsif node.has_attribute?('data-project')
+          project = Project.find(node.attr('data-project')) rescue nil
+          return unless project
+
+          { user: project.team.members.flatten }
+        end
+      end
+
+      def self.user_can_reference?(user, node)
+        if node.has_attribute?('data-group')
+          group = Group.find(node.attr('data-group')) rescue nil
+          Ability.abilities.allowed?(user, :read_group, group)
+        else
+          super
+        end
+      end
+
       def call
         replace_text_nodes_matching(User.reference_pattern) do |content|
           user_link_filter(content)
@@ -61,14 +89,12 @@ module Gitlab
       def link_to_all
         project = context[:project]
 
-        # FIXME (rspeicher): Law of Demeter
-        push_result(:user, *project.team.members.flatten)
-
         url = urls.namespace_project_url(project.namespace, project,
                                          only_path: context[:only_path])
+        data = data_attribute(project: project.id)
 
         text = User.reference_prefix + 'all'
-        %(<a href="#{url}" class="#{link_class}">#{text}</a>)
+        %(<a href="#{url}" #{data} class="#{link_class}">#{text}</a>)
       end
 
       def link_to_namespace(namespace)
@@ -80,20 +106,16 @@ module Gitlab
       end
 
       def link_to_group(group, namespace)
-        push_result(:user, *namespace.users)
-
         url = urls.group_url(group, only_path: context[:only_path])
-        data = data_attribute(namespace.id, :group)
+        data = data_attribute(group: namespace.id)
 
         text = Group.reference_prefix + group
         %(<a href="#{url}" #{data} class="#{link_class}">#{text}</a>)
       end
 
       def link_to_user(user, namespace)
-        push_result(:user, namespace.owner)
-
         url = urls.user_url(user, only_path: context[:only_path])
-        data = data_attribute(namespace.owner_id, :user)
+        data = data_attribute(user: namespace.owner_id)
 
         text = User.reference_prefix + user
         %(<a href="#{url}" #{data} class="#{link_class}">#{text}</a>)
diff --git a/lib/gitlab/reference_extractor.rb b/lib/gitlab/reference_extractor.rb
index 0961bd80421..2e546ef0d54 100644
--- a/lib/gitlab/reference_extractor.rb
+++ b/lib/gitlab/reference_extractor.rb
@@ -50,7 +50,7 @@ module Gitlab
         ignore_blockquotes: true
       }
 
-      pipeline = HTML::Pipeline.new([filter], context)
+      pipeline = HTML::Pipeline.new([filter, Gitlab::Markdown::ReferenceGathererFilter], context)
       result = pipeline.call(@text)
 
       result[:references][filter_type]