1 files changed, 106 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
new file mode 100644
index 0000000000..24e7bc65fa
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3/schema_statements.rb
@@ -0,0 +1,106 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module SQLite3
+      module SchemaStatements # :nodoc:
+        # Returns an array of indexes for the given table.
+        def indexes(table_name)
+          exec_query("PRAGMA index_list(#{quote_table_name(table_name)})", "SCHEMA").map do |row|
+            # Indexes SQLite creates implicitly for internal use start with "sqlite_".
+            # See https://www.sqlite.org/fileformat2.html#intschema
+            next if row["name"].starts_with?("sqlite_")
+
+            index_sql = query_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>.+)$/i =~ index_sql
+
+            columns = exec_query("PRAGMA index_info(#{quote(row['name'])})", "SCHEMA").map do |col|
+              col["name"]
+            end
+
+            # Add info on sort order for columns (only desc order is explicitly specified, asc is
+            # the default)
+            orders = {}
+            if index_sql # index_sql can be null in case of primary key indexes
+              index_sql.scan(/"(\w+)" DESC/).flatten.each { |order_column|
+                orders[order_column] = :desc
+              }
+            end
+
+            IndexDefinition.new(
+              table_name,
+              row["name"],
+              row["unique"] != 0,
+              columns,
+              where: where,
+              orders: orders
+            )
+          end.compact
+        end
+
+        def create_schema_dumper(options)
+          SQLite3::SchemaDumper.create(self, options)
+        end
+
+        private
+          def schema_creation
+            SQLite3::SchemaCreation.new(self)
+          end
+
+          def create_table_definition(*args)
+            SQLite3::TableDefinition.new(*args)
+          end
+
+          def new_column_from_field(table_name, field)
+            default = \
+              case field["dflt_value"]
+              when /^null$/i
+                nil
+              when /^'(.*)'$/m
+                $1.gsub("''", "'")
+              when /^"(.*)"$/m
+                $1.gsub('""', '"')
+              else
+                field["dflt_value"]
+              end
+
+            type_metadata = fetch_type_metadata(field["type"])
+            Column.new(field["name"], default, type_metadata, field["notnull"].to_i == 0, table_name, nil, field["collation"])
+          end
+
+          def data_source_sql(name = nil, type: nil)
+            scope = quoted_scope(name, type: type)
+            scope[:type] ||= "'table','view'"
+
+            sql = "SELECT name FROM sqlite_master WHERE name <> 'sqlite_sequence'".dup
+            sql << " AND name = #{scope[:name]}" if scope[:name]
+            sql << " AND type IN (#{scope[:type]})"
+            sql
+          end
+
+          def quoted_scope(name = nil, type: nil)
+            type = \
+              case type
+              when "BASE TABLE"
+                "'table'"
+              when "VIEW"
+                "'view'"
+              end
+            scope = {}
+            scope[:name] = quote(name) if name
+            scope[:type] = type if type
+            scope
+          end
+      end
+    end
+  end
+end