12 files changed, 405 insertions, 33 deletions

diff --git a/app/models/concerns/discussion_on_diff.rb b/app/models/concerns/discussion_on_diff.rb
new file mode 100644
index 00000000000..87db0c810c3
--- /dev/null
+++ b/app/models/concerns/discussion_on_diff.rb
@@ -0,0 +1,57 @@
+# Contains functionality shared between `DiffDiscussion` and `LegacyDiffDiscussion`.
+module DiscussionOnDiff
+  extend ActiveSupport::Concern
+
+  included do
+    NUMBER_OF_TRUNCATED_DIFF_LINES = 16
+
+    memoized_values << :active
+
+    delegate  :line_code,
+              :original_line_code,
+              :diff_file,
+              :diff_line,
+              :for_line?,
+              :active?,
+
+              to: :first_note
+
+    delegate  :file_path,
+              :blob,
+              :highlighted_diff_lines,
+              :diff_lines,
+
+              to: :diff_file,
+              allow_nil: true
+  end
+
+  def diff_discussion?
+    true
+  end
+
+  def active?
+    return @active if @active.present?
+
+    @active = first_note.active?
+  end
+
+  # Returns an array of at most 16 highlighted lines above a diff note
+  def truncated_diff_lines(highlight: true)
+    lines = highlight ? highlighted_diff_lines : diff_lines
+    prev_lines = []
+
+    lines.each do |line|
+      if line.meta?
+        prev_lines.clear
+      else
+        prev_lines << line
+
+        break if for_line?(line)
+
+        prev_lines.shift if prev_lines.length >= NUMBER_OF_TRUNCATED_DIFF_LINES
+      end
+    end
+
+    prev_lines
+  end
+end
diff --git a/app/models/concerns/has_status.rb b/app/models/concerns/has_status.rb
index 0a1a65da05a..dff7b6e3523 100644
--- a/app/models/concerns/has_status.rb
+++ b/app/models/concerns/has_status.rb
@@ -68,7 +68,7 @@ module HasStatus
     end
 
     scope :created, -> { where(status: 'created') }
-    scope :relevant, -> { where.not(status: 'created') }
+    scope :relevant, -> { where(status: AVAILABLE_STATUSES - ['created']) }
     scope :running, -> { where(status: 'running') }
     scope :pending, -> { where(status: 'pending') }
     scope :success, -> { where(status: 'success') }
@@ -76,6 +76,7 @@ module HasStatus
     scope :canceled, -> { where(status: 'canceled')  }
     scope :skipped, -> { where(status: 'skipped')  }
     scope :manual, -> { where(status: 'manual')  }
+    scope :created_or_pending, -> { where(status: [:created, :pending]) }
     scope :running_or_pending, -> { where(status: [:running, :pending]) }
     scope :finished, -> { where(status: [:success, :failed, :canceled]) }
     scope :failed_or_canceled, -> { where(status: [:failed, :canceled]) }
diff --git a/app/models/concerns/ignorable_column.rb b/app/models/concerns/ignorable_column.rb
new file mode 100644
index 00000000000..eb9f3423e48
--- /dev/null
+++ b/app/models/concerns/ignorable_column.rb
@@ -0,0 +1,28 @@
+# Module that can be included into a model to make it easier to ignore database
+# columns.
+#
+# Example:
+#
+#     class User < ActiveRecord::Base
+#       include IgnorableColumn
+#
+#       ignore_column :updated_at
+#     end
+#
+module IgnorableColumn
+  extend ActiveSupport::Concern
+
+  module ClassMethods
+    def columns
+      super.reject { |column| ignored_columns.include?(column.name) }
+    end
+
+    def ignored_columns
+      @ignored_columns ||= Set.new
+    end
+
+    def ignore_column(name)
+      ignored_columns << name.to_s
+    end
+  end
+end
diff --git a/app/models/concerns/issuable.rb b/app/models/concerns/issuable.rb
index b4dded7e27e..3d2258d5e3e 100644
--- a/app/models/concerns/issuable.rb
+++ b/app/models/concerns/issuable.rb
@@ -292,17 +292,6 @@ module Issuable
     self.class.to_ability_name
   end
 
-  # Convert this Issuable class name to a format usable by notifications.
-  #
-  # Examples:
-  #
-  #   issuable.class           # => MergeRequest
-  #   issuable.human_class_name # => "merge request"
-
-  def human_class_name
-    @human_class_name ||= self.class.name.titleize.downcase
-  end
-
   # Returns a Hash of attributes to be used for Twitter card metadata
   def card_attributes
     {
diff --git a/app/models/concerns/note_on_diff.rb b/app/models/concerns/note_on_diff.rb
index b8dd27a7afe..1a5a7007a2b 100644
--- a/app/models/concerns/note_on_diff.rb
+++ b/app/models/concerns/note_on_diff.rb
@@ -1,3 +1,4 @@
+# Contains functionality shared between `DiffNote` and `LegacyDiffNote`.
 module NoteOnDiff
   extend ActiveSupport::Concern
 
@@ -24,12 +25,4 @@ module NoteOnDiff
   def diff_attributes
     raise NotImplementedError
   end
-
-  def can_be_award_emoji?
-    false
-  end
-
-  def to_discussion
-    Discussion.new([self])
-  end
 end
diff --git a/app/models/concerns/noteable.rb b/app/models/concerns/noteable.rb
new file mode 100644
index 00000000000..772ff6a6d2f
--- /dev/null
+++ b/app/models/concerns/noteable.rb
@@ -0,0 +1,68 @@
+module Noteable
+  # Names of all implementers of `Noteable` that support resolvable notes.
+  RESOLVABLE_TYPES = %w(MergeRequest).freeze
+
+  def base_class_name
+    self.class.base_class.name
+  end
+
+  # Convert this Noteable class name to a format usable by notifications.
+  #
+  # Examples:
+  #
+  #   noteable.class           # => MergeRequest
+  #   noteable.human_class_name # => "merge request"
+  def human_class_name
+    @human_class_name ||= base_class_name.titleize.downcase
+  end
+
+  def supports_resolvable_notes?
+    RESOLVABLE_TYPES.include?(base_class_name)
+  end
+
+  def supports_discussions?
+    DiscussionNote::NOTEABLE_TYPES.include?(base_class_name)
+  end
+
+  def discussion_notes
+    notes
+  end
+
+  delegate :find_discussion, to: :discussion_notes
+
+  def discussions
+    @discussions ||= discussion_notes
+      .inc_relations_for_view
+      .discussions(self)
+  end
+
+  def grouped_diff_discussions
+    # Doesn't use `discussion_notes`, because this may include commit diff notes
+    # besides MR diff notes, that we do no want to display on the MR Changes tab.
+    notes.inc_relations_for_view.grouped_diff_discussions
+  end
+
+  def resolvable_discussions
+    @resolvable_discussions ||= discussion_notes.resolvable.discussions(self)
+  end
+
+  def discussions_resolvable?
+    resolvable_discussions.any?(&:resolvable?)
+  end
+
+  def discussions_resolved?
+    discussions_resolvable? && resolvable_discussions.none?(&:to_be_resolved?)
+  end
+
+  def discussions_to_be_resolved?
+    discussions_resolvable? && !discussions_resolved?
+  end
+
+  def discussions_to_be_resolved
+    @discussions_to_be_resolved ||= resolvable_discussions.select(&:to_be_resolved?)
+  end
+
+  def discussions_can_be_resolved_by?(user)
+    discussions_to_be_resolved.all? { |discussion| discussion.can_resolve?(user) }
+  end
+end
diff --git a/app/models/concerns/protected_branch_access.rb b/app/models/concerns/protected_branch_access.rb
index 9dd4d9c6f24..c41b807df8a 100644
--- a/app/models/concerns/protected_branch_access.rb
+++ b/app/models/concerns/protected_branch_access.rb
@@ -2,20 +2,10 @@ module ProtectedBranchAccess
   extend ActiveSupport::Concern
 
   included do
-    belongs_to :protected_branch
-    delegate :project, to: :protected_branch
-
-    scope :master, -> { where(access_level: Gitlab::Access::MASTER) }
-    scope :developer, -> { where(access_level: Gitlab::Access::DEVELOPER) }
-  end
+    include ProtectedRefAccess
 
-  def humanize
-    self.class.human_access_levels[self.access_level]
-  end
-
-  def check_access(user)
-    return true if user.is_admin?
+    belongs_to :protected_branch
 
-    project.team.max_member_access(user.id) >= access_level
+    delegate :project, to: :protected_branch
   end
 end
diff --git a/app/models/concerns/protected_ref.rb b/app/models/concerns/protected_ref.rb
new file mode 100644
index 00000000000..62eaec2407f
--- /dev/null
+++ b/app/models/concerns/protected_ref.rb
@@ -0,0 +1,42 @@
+module ProtectedRef
+  extend ActiveSupport::Concern
+
+  included do
+    belongs_to :project
+
+    validates :name, presence: true
+    validates :project, presence: true
+
+    delegate :matching, :matches?, :wildcard?, to: :ref_matcher
+
+    def self.protected_ref_accessible_to?(ref, user, action:)
+      access_levels_for_ref(ref, action: action).any? do |access_level|
+        access_level.check_access(user)
+      end
+    end
+
+    def self.developers_can?(action, ref)
+      access_levels_for_ref(ref, action: action).any? do |access_level|
+        access_level.access_level == Gitlab::Access::DEVELOPER
+      end
+    end
+
+    def self.access_levels_for_ref(ref, action:)
+      self.matching(ref).map(&:"#{action}_access_levels").flatten
+    end
+
+    def self.matching(ref_name, protected_refs: nil)
+      ProtectedRefMatcher.matching(self, ref_name, protected_refs: protected_refs)
+    end
+  end
+
+  def commit
+    project.commit(self.name)
+  end
+
+  private
+
+  def ref_matcher
+    @ref_matcher ||= ProtectedRefMatcher.new(self)
+  end
+end
diff --git a/app/models/concerns/protected_ref_access.rb b/app/models/concerns/protected_ref_access.rb
new file mode 100644
index 00000000000..c4f158e569a
--- /dev/null
+++ b/app/models/concerns/protected_ref_access.rb
@@ -0,0 +1,18 @@
+module ProtectedRefAccess
+  extend ActiveSupport::Concern
+
+  included do
+    scope :master, -> { where(access_level: Gitlab::Access::MASTER) }
+    scope :developer, -> { where(access_level: Gitlab::Access::DEVELOPER) }
+  end
+
+  def humanize
+    self.class.human_access_levels[self.access_level]
+  end
+
+  def check_access(user)
+    return true if user.admin?
+
+    project.team.max_member_access(user.id) >= access_level
+  end
+end
diff --git a/app/models/concerns/protected_tag_access.rb b/app/models/concerns/protected_tag_access.rb
new file mode 100644
index 00000000000..ee65de24dd8
--- /dev/null
+++ b/app/models/concerns/protected_tag_access.rb
@@ -0,0 +1,11 @@
+module ProtectedTagAccess
+  extend ActiveSupport::Concern
+
+  included do
+    include ProtectedRefAccess
+
+    belongs_to :protected_tag
+
+    delegate :project, to: :protected_tag
+  end
+end
diff --git a/app/models/concerns/resolvable_discussion.rb b/app/models/concerns/resolvable_discussion.rb
new file mode 100644
index 00000000000..dd979e7bb17
--- /dev/null
+++ b/app/models/concerns/resolvable_discussion.rb
@@ -0,0 +1,103 @@
+module ResolvableDiscussion
+  extend ActiveSupport::Concern
+
+  included do
+    # A number of properties of this `Discussion`, like `first_note` and `resolvable?`, are memoized.
+    # When this discussion is resolved or unresolved, the values of these properties potentially change.
+    # To make sure all memoized values are reset when this happens, `update` resets all instance variables with names in
+    # `memoized_variables`. If you add a memoized method in `ResolvableDiscussion` or any `Discussion` subclass,
+    # please make sure the instance variable name is added to `memoized_values`, like below.
+    cattr_accessor :memoized_values, instance_accessor: false do
+      []
+    end
+
+    memoized_values.push(
+      :resolvable,
+      :resolved,
+      :first_note,
+      :first_note_to_resolve,
+      :last_resolved_note,
+      :last_note
+    )
+
+    delegate :potentially_resolvable?, to: :first_note
+
+    delegate  :resolved_at,
+              :resolved_by,
+
+              to: :last_resolved_note,
+              allow_nil: true
+  end
+
+  def resolvable?
+    return @resolvable if @resolvable.present?
+
+    @resolvable = potentially_resolvable? && notes.any?(&:resolvable?)
+  end
+
+  def resolved?
+    return @resolved if @resolved.present?
+
+    @resolved = resolvable? && notes.none?(&:to_be_resolved?)
+  end
+
+  def first_note
+    @first_note ||= notes.first
+  end
+
+  def first_note_to_resolve
+    return unless resolvable?
+
+    @first_note_to_resolve ||= notes.find(&:to_be_resolved?)
+  end
+
+  def last_resolved_note
+    return unless resolved?
+
+    @last_resolved_note ||= resolved_notes.sort_by(&:resolved_at).last
+  end
+
+  def resolved_notes
+    notes.select(&:resolved?)
+  end
+
+  def to_be_resolved?
+    resolvable? && !resolved?
+  end
+
+  def can_resolve?(current_user)
+    return false unless current_user
+    return false unless resolvable?
+
+    current_user == self.noteable.author ||
+      current_user.can?(:resolve_note, self.project)
+  end
+
+  def resolve!(current_user)
+    return unless resolvable?
+
+    update { |notes| notes.resolve!(current_user) }
+  end
+
+  def unresolve!
+    return unless resolvable?
+
+    update { |notes| notes.unresolve! }
+  end
+
+  private
+
+  def update
+    # Do not select `Note.resolvable`, so that system notes remain in the collection
+    notes_relation = Note.where(id: notes.map(&:id))
+
+    yield(notes_relation)
+
+    # Set the notes array to the updated notes
+    @notes = notes_relation.fresh.to_a
+
+    self.class.memoized_values.each do |var|
+      instance_variable_set(:"@#{var}", nil)
+    end
+  end
+end
diff --git a/app/models/concerns/resolvable_note.rb b/app/models/concerns/resolvable_note.rb
new file mode 100644
index 00000000000..05eb6f86704
--- /dev/null
+++ b/app/models/concerns/resolvable_note.rb
@@ -0,0 +1,72 @@
+module ResolvableNote
+  extend ActiveSupport::Concern
+
+  # Names of all subclasses of `Note` that can be resolvable.
+  RESOLVABLE_TYPES = %w(DiffNote DiscussionNote).freeze
+
+  included do
+    belongs_to :resolved_by, class_name: "User"
+
+    validates :resolved_by, presence: true, if: :resolved?
+
+    # Keep this scope in sync with `#potentially_resolvable?`
+    scope :potentially_resolvable, -> { where(type: RESOLVABLE_TYPES).where(noteable_type: Noteable::RESOLVABLE_TYPES) }
+    # Keep this scope in sync with `#resolvable?`
+    scope :resolvable, -> { potentially_resolvable.user }
+
+    scope :resolved, -> { resolvable.where.not(resolved_at: nil) }
+    scope :unresolved, -> { resolvable.where(resolved_at: nil) }
+  end
+
+  module ClassMethods
+    # This method must be kept in sync with `#resolve!`
+    def resolve!(current_user)
+      unresolved.update_all(resolved_at: Time.now, resolved_by_id: current_user.id)
+    end
+
+    # This method must be kept in sync with `#unresolve!`
+    def unresolve!
+      resolved.update_all(resolved_at: nil, resolved_by_id: nil)
+    end
+  end
+
+  # Keep this method in sync with the `potentially_resolvable` scope
+  def potentially_resolvable?
+    RESOLVABLE_TYPES.include?(self.class.name) && noteable.supports_resolvable_notes?
+  end
+
+  # Keep this method in sync with the `resolvable` scope
+  def resolvable?
+    potentially_resolvable? && !system?
+  end
+
+  def resolved?
+    return false unless resolvable?
+
+    self.resolved_at.present?
+  end
+
+  def to_be_resolved?
+    resolvable? && !resolved?
+  end
+
+  # If you update this method remember to also update `.resolve!`
+  def resolve!(current_user)
+    return unless resolvable?
+    return if resolved?
+
+    self.resolved_at = Time.now
+    self.resolved_by = current_user
+    save!
+  end
+
+  # If you update this method remember to also update `.unresolve!`
+  def unresolve!
+    return unless resolvable?
+    return unless resolved?
+
+    self.resolved_at = nil
+    self.resolved_by = nil
+    save!
+  end
+end