1 files changed, 162 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb b/activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb
new file mode 100644
index 0000000000..6adcc14545
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb
@@ -0,0 +1,162 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ConnectionAdapters
+    module MySQL
+      module DatabaseStatements
+        # Returns an ActiveRecord::Result instance.
+        def select_all(*) # :nodoc:
+          result = if ExplainRegistry.collect? && prepared_statements
+            unprepared_statement { super }
+          else
+            super
+          end
+          discard_remaining_results
+          result
+        end
+
+        def query(sql, name = nil) # :nodoc:
+          execute(sql, name).to_a
+        end
+
+        READ_QUERY = ActiveRecord::ConnectionAdapters::AbstractAdapter.build_read_query_regexp(:begin, :commit, :explain, :select, :set, :show, :release, :savepoint, :rollback) # :nodoc:
+        private_constant :READ_QUERY
+
+        def write_query?(sql) # :nodoc:
+          !READ_QUERY.match?(sql)
+        end
+
+        # Executes the SQL statement in the context of this connection.
+        def execute(sql, name = nil)
+          if preventing_writes? && write_query?(sql)
+            raise ActiveRecord::ReadOnlyError, "Write query attempted while in readonly mode: #{sql}"
+          end
+
+          # make sure we carry over any changes to ActiveRecord::Base.default_timezone that have been
+          # made since we established the connection
+          @connection.query_options[:database_timezone] = ActiveRecord::Base.default_timezone
+
+          super
+        end
+
+        def exec_query(sql, name = "SQL", binds = [], prepare: false)
+          if without_prepared_statement?(binds)
+            execute_and_free(sql, name) do |result|
+              if result
+                ActiveRecord::Result.new(result.fields, result.to_a)
+              else
+                ActiveRecord::Result.new([], [])
+              end
+            end
+          else
+            exec_stmt_and_free(sql, name, binds, cache_stmt: prepare) do |_, result|
+              if result
+                ActiveRecord::Result.new(result.fields, result.to_a)
+              else
+                ActiveRecord::Result.new([], [])
+              end
+            end
+          end
+        end
+
+        def exec_delete(sql, name = nil, binds = [])
+          if without_prepared_statement?(binds)
+            execute_and_free(sql, name) { @connection.affected_rows }
+          else
+            exec_stmt_and_free(sql, name, binds) { |stmt| stmt.affected_rows }
+          end
+        end
+        alias :exec_update :exec_delete
+
+        private
+          def default_insert_value(column)
+            Arel.sql("DEFAULT") unless column.auto_increment?
+          end
+
+          def last_inserted_id(result)
+            @connection.last_id
+          end
+
+          def discard_remaining_results
+            @connection.abandon_results!
+          end
+
+          def supports_set_server_option?
+            @connection.respond_to?(:set_server_option)
+          end
+
+          def multi_statements_enabled?(flags)
+            if flags.is_a?(Array)
+              flags.include?("MULTI_STATEMENTS")
+            else
+              (flags & Mysql2::Client::MULTI_STATEMENTS) != 0
+            end
+          end
+
+          def with_multi_statements
+            previous_flags = @config[:flags]
+
+            unless multi_statements_enabled?(previous_flags)
+              if supports_set_server_option?
+                @connection.set_server_option(Mysql2::Client::OPTION_MULTI_STATEMENTS_ON)
+              else
+                @config[:flags] = Mysql2::Client::MULTI_STATEMENTS
+                reconnect!
+              end
+            end
+
+            yield
+          ensure
+            unless multi_statements_enabled?(previous_flags)
+              if supports_set_server_option?
+                @connection.set_server_option(Mysql2::Client::OPTION_MULTI_STATEMENTS_OFF)
+              else
+                @config[:flags] = previous_flags
+                reconnect!
+              end
+            end
+          end
+
+          def exec_stmt_and_free(sql, name, binds, cache_stmt: false)
+            if preventing_writes? && write_query?(sql)
+              raise ActiveRecord::ReadOnlyError, "Write query attempted while in readonly mode: #{sql}"
+            end
+
+            materialize_transactions
+
+            # make sure we carry over any changes to ActiveRecord::Base.default_timezone that have been
+            # made since we established the connection
+            @connection.query_options[:database_timezone] = ActiveRecord::Base.default_timezone
+
+            type_casted_binds = type_casted_binds(binds)
+
+            log(sql, name, binds, type_casted_binds) do
+              if cache_stmt
+                stmt = @statements[sql] ||= @connection.prepare(sql)
+              else
+                stmt = @connection.prepare(sql)
+              end
+
+              begin
+                result = ActiveSupport::Dependencies.interlock.permit_concurrent_loads do
+                  stmt.execute(*type_casted_binds)
+                end
+              rescue Mysql2::Error => e
+                if cache_stmt
+                  @statements.delete(sql)
+                else
+                  stmt.close
+                end
+                raise e
+              end
+
+              ret = yield stmt, result
+              result.free if result
+              stmt.close unless cache_stmt
+              ret
+            end
+          end
+      end
+    end
+  end
+end