tobixdev commented on code in PR #18552: URL: https://github.com/apache/datafusion/pull/18552#discussion_r2514582475
########## datafusion/common/src/types/canonical.rs: ########## @@ -0,0 +1,198 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +use crate::error::_internal_err; +use crate::types::{ + LogicalType, NativeType, TypeParameter, TypeSignature, ValuePrettyPrinter, +}; +use crate::ScalarValue; +use crate::{Result, _internal_datafusion_err}; +use arrow_schema::extension::{ExtensionType, Opaque, Uuid}; +use std::sync::{Arc, LazyLock}; +use uuid::Bytes; + +impl LogicalType for Uuid { + fn native(&self) -> &NativeType { + &NativeType::FixedSizeBinary(16) + } + + fn signature(&self) -> TypeSignature<'_> { + TypeSignature::Extension { + name: Uuid::NAME, + parameters: vec![], + } + } + + fn pretty_printer(&self) -> &Arc<dyn ValuePrettyPrinter> { + static PRETTY_PRINTER: LazyLock<Arc<dyn ValuePrettyPrinter>> = + LazyLock::new(|| Arc::new(UuidValuePrettyPrinter {})); + &PRETTY_PRINTER + } +} + +#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, Hash)] +struct UuidValuePrettyPrinter; + +impl ValuePrettyPrinter for UuidValuePrettyPrinter { + fn pretty_print_scalar(&self, value: &ScalarValue) -> Result<String> { + match value { + ScalarValue::FixedSizeBinary(16, value) => match value { + Some(value) => { + let bytes = Bytes::try_from(value.as_slice()).map_err(|_| { + _internal_datafusion_err!( + "Invalid UUID bytes even though type is correct." + ) + })?; + let uuid = uuid::Uuid::from_bytes(bytes); + Ok(format!("arrow.uuid({uuid})")) + } + None => Ok("arrow.uuid(NULL)".to_owned()), + }, + _ => _internal_err!("Wrong scalar given to "), + } + } +} + +/// Represents the canonical [Opaque extension type](https://arrow.apache.org/docs/format/CanonicalExtensions.html#opaque). +/// +/// In the context of DataFusion, a common use case of the opaque type is when an extension type +/// is unknown to DataFusion. Contrary to [UnresolvedExtensionType], the extension type has +/// already been checked against the extension type registry and was not found. +impl LogicalType for Opaque { Review Comment: Yeah maybe I misunderstood the Opaque type here. > it is a place where we can define what happens to a field with ARROW:extension:name in the absence of any other guidance (e.g., here we would print values identically to the storage type...we could define equality here using byte-for-byte equality of metadata if we want to be strict, or using storage type equality if we want to be lenient). Yes, exactly. I think we can still discuss what's is the stance on how lenient we want to be with unknown types, especially regarding code that is relevant for planning / computations etc. If I get this correctly, this should be another logical type called something like `datafusion.unknown`? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
