#424

backend/app/controllers/wiki_pages_controller.rb

@@ -9,7 +9,8 @@ class WikiPagesController < ApplicationController
         TagDescription.where(language_code: 'ja')
         .includes(tag: :tag_names)
 
-    tag_groups = TagGroup.all
+    descriptions = descriptions.order(updated_at: :desc, id: :asc)
+    tag_groups = TagGroup.order(updated_at: :desc, id: :asc)
     if title.present?
       pattern = "%#{ ApplicationRecord.sanitize_sql_like(title) }%"
       descriptions =
@@ -22,7 +23,9 @@ class WikiPagesController < ApplicationController
 
     json = descriptions.map { |description| WikiPageRepr.tag_description(description) }
     json.concat(tag_groups.map { WikiPageRepr.tag_group(_1) })
-    json.sort! { |a, b| b['updated_at'] <=> a['updated_at'] }
+    json.sort_by! do |row|
+      [-row['updated_at'].to_f, row.fetch('resource_type'), row.fetch('id')]
+    end
     json = json.first(20) if title.present?
     render json:
   end
@@ -99,7 +102,7 @@ class WikiPagesController < ApplicationController
                      'title' => "#{ TagGroupRepr::PREFIX }#{ tag_group.name }",
                      'deprecated_at' => nil }
       else
-        raise 'お前やりませんねぇスギ!'
+        return head :not_found
       end
     end
 
@@ -141,7 +144,7 @@ class WikiPagesController < ApplicationController
 
     page =
         if title.include?(':')
-          raise 'お前やりませんねぇスギ!'
+          return render_unprocessable_entity field: :title
         else
           tag_name = TagName.find_by(language_code: 'ja', name: title)
           return render_unprocessable_entity field: :title unless tag_name&.tag
@@ -150,7 +153,8 @@ class WikiPagesController < ApplicationController
               tag: tag_name.tag, body:, created_by_user: current_user, message:)
         end
 
-    render json: WikiPageRepr.base(page), status: :created
+    description = TagDescription.find_by!(tag_id: page.tag_name.tag_id, language_code: 'ja')
+    render json: WikiPageRepr.tag_description(description), status: :created
   rescue ActiveRecord::RecordInvalid => e
     render_validation_error e.record
   rescue ActiveRecord::RecordNotUnique
@@ -180,44 +184,34 @@ class WikiPagesController < ApplicationController
       return head :ok
     end
 
-    page = WikiPage.find_by(id: params[:id])
-    if legacy_group_page?(page)
+    return render_unprocessable_entity field: :title if title.include?(':')
+    description = TagDescription.find_by(id: params[:id])
+    unless description
+      return render_unprocessable_entity field: :title if group || WikiPage.exists?(id: params[:id])
+      return head :not_found
+    end
+    tag = description.tag
+    tag_name = TagDescriptionOperation.compatibility_tag_name(tag)
+    if tag_name.name.include?(':') || (group && title != tag_name.name)
       return render_unprocessable_entity field: :title
     end
-    if group && !legacy_update_identified?(page, title, group)
-      return render_unprocessable_entity field: :title
-    end
-    return head :not_found unless page
 
     base_revision_id = params[:base_revision_id].presence
 
     ApplicationRecord.transaction do
-      page.lock!
-
-      old_title = page.title
-
-      tag = page.tag_name.tag
-
-      if tag && title != old_title
+      tag.lock!
+      old_title = tag_name.name
+      if title != old_title
         TagVersioning.ensure_snapshot!(tag, created_by_user: current_user)
       end
 
-      page.tag_name.update!(name: title) if title != old_title
+      tag_name.update!(name: title) if title != old_title
 
       message = params[:message].presence
-      description = TagDescription.find_by(id: page.id)
-      description_page = description && (
-          tag&.id == description.tag_id ||
-          (tag.nil? && !old_title.include?(':')))
-      if description && !description_page
-        Wiki::Commit.legacy_content!(page:, body:, created_user: current_user,
-                                     message:, base_revision_id:)
-      else
-        Wiki::Commit.content!(page:, body:, created_user: current_user,
-                              message:, base_revision_id:)
-      end
+      TagDescriptionOperation.update!(tag:, body:, updated_by_user: current_user,
+                                      message:, base_revision_id:)
 
-      if tag && title != old_title
+      if title != old_title
         tag.reload
         TagVersionRecorder.record!(tag:, event_type: :update, created_by_user: current_user)
       end
@@ -306,6 +300,7 @@ class WikiPagesController < ApplicationController
     updated_at = version.created_at
     render json: {
         'id' => version.tag_group_id,
+        'resource_type' => 'tag_group',
         'title' => "#{ TagGroupRepr::PREFIX }#{ representation.fetch('name') }",
         'deprecated_at' => nil,
         'body' => body,

backend/app/models/external_tag.rb

@@ -1,4 +1,6 @@
 class ExternalTag < ApplicationRecord
+  before_create { SharedResourceIdAllocator.assign!(self) }
+
   enum :platform, nico: 'nico'
   validates :platform, presence: true, inclusion: { in: ExternalTag.platforms.keys }
 

backend/app/models/tag.rb

@@ -2,6 +2,8 @@ require 'set'
 
 
 class Tag < ApplicationRecord
+  before_create { SharedResourceIdAllocator.assign!(self) }
+
   class NicoTagNormalisationError < ArgumentError
     ;
   end

backend/app/models/tag_description.rb

@@ -1,3 +1,5 @@
 class TagDescription < ApplicationRecord
+  before_create { SharedResourceIdAllocator.assign!(self) }
+
   belongs_to :tag
 end

backend/app/models/tag_group.rb

@@ -1,4 +1,6 @@
 class TagGroup < ApplicationRecord
+  before_create { SharedResourceIdAllocator.assign!(self) }
+
   belongs_to :created_by_user, class_name: 'User', optional: true
   belongs_to :updated_by_user, class_name: 'User', optional: true
 

backend/app/representations/wiki_page_repr.rb

@@ -13,6 +13,7 @@ module WikiPageRepr
   def tag_description description
     tag = description.tag
     { 'id' => description.id,
+      'resource_type' => 'tag_description',
       'tag_name_id' => tag.tag_name('ja')&.id,
       'body' => description.body,
       'created_user_id' => description.created_by_user_id,
@@ -26,7 +27,7 @@ module WikiPageRepr
   end
 
   def tag_group tag_group
-    TagGroupRepr.tag_group(tag_group)
+    TagGroupRepr.tag_group(tag_group).merge('resource_type' => 'tag_group')
   end
 
   def many wiki_pages

backend/app/services/shared_resource_id_allocator.rb

@@ -0,0 +1,56 @@
+require 'digest'
+
+
+class SharedResourceIdAllocator
+  SPACES = {
+      'tags' => ['tags', 'external_tags'],
+      'wiki' => ['tag_descriptions', 'tag_groups'] }.freeze
+  LOCK_TIMEOUT = 10
+
+  def self.assign! record
+    space, tables = SPACES.find { |_name, names| names.include?(record.class.table_name) }
+    raise ArgumentError, 'Unknown shared ID resource' unless tables
+
+    connection = record.class.connection
+    transaction = record.class.current_transaction
+    raise ActiveRecord::ActiveRecordError, 'Shared ID requires a transaction' unless transaction.open?
+
+    database = connection.pool.db_config.database
+    name = "btrc:ids:#{ Digest::SHA256.hexdigest(database)[0, 16] }:#{ space }"
+    quoted_name = connection.quote(name)
+    acquired = record.class.uncached do
+      connection.select_value("SELECT GET_LOCK(#{ quoted_name }, #{ LOCK_TIMEOUT })")
+    end
+    unless acquired.to_i == 1
+      raise ActiveRecord::LockWaitTimeout, "Shared ID lock unavailable: #{ space }"
+    end
+
+    release = lambda do
+      result = record.class.uncached do
+        connection.select_value("SELECT RELEASE_LOCK(#{ quoted_name })")
+      end
+      unless result.to_i == 1
+        raise ActiveRecord::ActiveRecordError, "Shared ID lock release failed: #{ space }"
+      end
+    end
+    begin
+      transaction.after_commit(&release)
+      transaction.after_rollback(&release)
+    rescue StandardError
+      release.call
+      raise
+    end
+
+    return if record.id.present?
+
+    # Locking reads see committed maxima even after earlier repeatable reads.
+    maxima = record.class.uncached do
+      tables.map do |table|
+        quoted_table = connection.quote_table_name(table)
+        connection.select_value(
+            "SELECT id FROM #{ quoted_table } ORDER BY id DESC LIMIT 1 FOR UPDATE").to_i
+      end
+    end
+    record.id = maxima.max + 1
+  end
+end

backend/app/services/tag_description_operation.rb

@@ -8,9 +8,9 @@ class TagDescriptionOperation
           tag_id: tag.id, language_code: LANGUAGE_CODE)
 
       page = Wiki::CompatibilityWriter.create!(
-          tag_name: tag.tag_name(LANGUAGE_CODE), body:, created_by_user:, message:)
+          tag_name: compatibility_tag_name(tag), body:, created_by_user:, message:)
       revision = page.wiki_revisions.order(id: :desc).first
-      record_version!(tag:, revision:, body:, user: created_by_user,
+      record_version!(tag:, revision:, body: revision.body, user: created_by_user,
                       description: nil)
       page
     end
@@ -22,7 +22,20 @@ class TagDescriptionOperation
       tag.lock!
       description = TagDescription.lock.find_by!(
           tag_id: tag.id, language_code: LANGUAGE_CODE)
-      page = WikiPage.lock.find(description.id)
+      tag_name = compatibility_tag_name(tag)
+      page = WikiPage.lock.find_by(tag_name_id: tag_name.id)
+      unless page
+        versions = TagDescriptionVersion.where(tag_id: tag.id, language_code: LANGUAGE_CODE)
+        if base_revision_id.present? && versions.maximum(:id) != base_revision_id.to_i
+          raise Wiki::Commit::Conflict, '競合が発生してゐます．'
+        end
+        page = Wiki::CompatibilityWriter.create!(
+            tag_name:, body:, created_by_user: updated_by_user, message:)
+        revision = page.current_revision
+        record_version!(tag:, revision:, body: revision.body,
+                        user: updated_by_user, description:)
+        next revision
+      end
       revision = Wiki::CompatibilityWriter.update!(
           page:, body:, updated_by_user:, message:,
           base_revision_id:)
@@ -34,6 +47,11 @@ class TagDescriptionOperation
     end
   end
 
+  def self.compatibility_tag_name tag
+    tag.tag_name(LANGUAGE_CODE) || TagName.find_by!(id: tag.tag_name_id,
+                                                  language_code: LANGUAGE_CODE)
+  end
+
   def self.record_version! tag:, revision:, body:, user:, description:
     version_no = description ? description.version_no + 1 : 1
     TagDescriptionVersion.create!(
@@ -44,7 +62,7 @@ class TagDescriptionOperation
       description.update!(body:, version_no:, updated_by_user_id: user.id)
     else
       TagDescription.create!(
-          id: revision.wiki_page_id, tag_id: tag.id,
+          tag_id: tag.id,
           language_code: LANGUAGE_CODE, version_no:, body:,
           created_by_user_id: user.id, updated_by_user_id: user.id)
     end

backend/app/services/tag_group_operation.rb

@@ -349,7 +349,7 @@ class TagGroupOperation
       tag_name.primary_flg = true
       tag_name.auto_generated = false
       tag_name.save!
-      Wiki::Commit.create_legacy_content!(tag_name:, body:, created_by_user: actor)
+      Wiki::CompatibilityWriter.create!(tag_name:, body:, created_by_user: actor)
     end
     nil
   end

backend/app/services/wiki/commit.rb

@@ -8,12 +8,13 @@ module Wiki
     end
 
     def self.create_content! tag_name:, body:, created_by_user:, message: nil
-      if tag_name.tag && tag_name.language_code == 'ja'
+      if tag_name.tag && tag_name.language_code == 'ja' && !tag_name.name.include?(':')
         return TagDescriptionOperation.create!(
             tag: tag_name.tag, body:, created_by_user:, message:)
       end
 
-      create_legacy_content!(tag_name:, body:, created_by_user:, message:)
+      tag_name.errors.add(:base, :invalid)
+      raise ActiveRecord::RecordInvalid, tag_name
     end
 
     def self.create_legacy_content! tag_name:, body:, created_by_user:, message: nil
@@ -42,14 +43,17 @@ module Wiki
     end
 
     def self.content! page:, body:, created_user:, message: nil, base_revision_id: nil
-      description = TagDescription.find_by(id: page.id)
-      if description
+      description = TagDescription.find_by(tag_id: page.tag_name.tag_id, language_code: 'ja')
+      description ||= TagDescription.joins(:tag).find_by(
+          tags: { tag_name_id: page.tag_name_id }, language_code: 'ja')
+      if description && !page.title.include?(':')
         return TagDescriptionOperation.update!(
             tag: description.tag, body:, updated_by_user: created_user,
             message:, base_revision_id:)
       end
 
-      legacy_content!(page:, body:, created_user:, message:, base_revision_id:)
+      page.errors.add(:base, :invalid)
+      raise ActiveRecord::RecordInvalid, page
     end
 
     def self.legacy_content! page:, body:, created_user:, message: nil,

backend/app/services/wiki/compatibility_writer.rb

@@ -1,8 +1,16 @@
 module Wiki
   class CompatibilityWriter
     def self.create! tag_name:, body:, created_by_user:, message: nil
-      Commit.create_legacy_content!(
-          tag_name:, body:, created_by_user:, message:)
+      ApplicationRecord.transaction do
+        tag_name.lock!
+        page = WikiPage.lock.find_by(tag_name_id: tag_name.id)
+        if page
+          update!(page:, body:, updated_by_user: created_by_user, message:)
+          page
+        else
+          Commit.create_legacy_content!(tag_name:, body:, created_by_user:, message:)
+        end
+      end
     end
 
     def self.update! page:, body:, updated_by_user:, message: nil,
@@ -23,7 +31,9 @@ module Wiki
         end
       end
 
-      return if Commit.normalise_body(page.body) == normalised
+      if Commit.normalise_body(page.body) == normalised && page.wiki_revisions.exists?
+        return
+      end
 
       Commit.legacy_content!(
           page:, body: normalised, created_user: updated_by_user, message:,