Refactor `indexes` things in connection adapters

* Use keyword arguments in `IndexDefinition` to ease to ignore unused
  options and to avoid to initialize incorrect empty value.
* Place it in `SchemaStatements` for consistency.
* And tiny tweaks.

1 files changed, 35 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/sqlite3/schema_statements.rb
index 8066a05c5e..e02491edb6 100644
--- a/activerecord/lib/active_record/connection_adapters/sqlite3/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3/schema_statements.rb
@@ -2,6 +2,41 @@ module ActiveRecord
   module ConnectionAdapters
     module SQLite3
       module SchemaStatements # :nodoc:
+        # Returns an array of indexes for the given table.
+        def indexes(table_name, name = nil)
+          if name
+            ActiveSupport::Deprecation.warn(<<-MSG.squish)
+              Passing name to #indexes is deprecated without replacement.
+            MSG
+          end
+
+          exec_query("PRAGMA index_list(#{quote_table_name(table_name)})", "SCHEMA").map do |row|
+            index_sql = select_value(<<-SQL, "SCHEMA")
+              SELECT sql
+              FROM sqlite_master
+              WHERE name = #{quote(row['name'])} AND type = 'index'
+              UNION ALL
+              SELECT sql
+              FROM sqlite_temp_master
+              WHERE name = #{quote(row['name'])} AND type = 'index'
+            SQL
+
+            /\sWHERE\s+(?<where>.+)$/i =~ index_sql
+
+            columns = exec_query("PRAGMA index_info(#{quote(row['name'])})", "SCHEMA").map do |col|
+              col["name"]
+            end
+
+            IndexDefinition.new(
+              table_name,
+              row["name"],
+              row["unique"] != 0,
+              columns,
+              where: where
+            )
+          end
+        end
+
         private
           def schema_creation
             SQLite3::SchemaCreation.new(self)