kszucs commented on a change in pull request #439: URL: https://github.com/apache/arrow-rs/pull/439#discussion_r655509158
########## File path: arrow/src/datatypes/ffi.rs ########## @@ -0,0 +1,287 @@ +// 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 std::convert::TryFrom; + +use crate::{ + datatypes::{DataType, Field, Schema, TimeUnit}, + error::{ArrowError, Result}, + ffi::{FFI_ArrowSchema, Flags}, +}; + +impl TryFrom<&FFI_ArrowSchema> for DataType { + type Error = ArrowError; + + /// See https://arrow.apache.org/docs/format/CDataInterface.html#data-type-description-format-strings + fn try_from(c_schema: &FFI_ArrowSchema) -> Result<Self> { + let dtype = match c_schema.format() { + "n" => DataType::Null, + "b" => DataType::Boolean, + "c" => DataType::Int8, + "C" => DataType::UInt8, + "s" => DataType::Int16, + "S" => DataType::UInt16, + "i" => DataType::Int32, + "I" => DataType::UInt32, + "l" => DataType::Int64, + "L" => DataType::UInt64, + "e" => DataType::Float16, + "f" => DataType::Float32, + "g" => DataType::Float64, + "z" => DataType::Binary, + "Z" => DataType::LargeBinary, + "u" => DataType::Utf8, + "U" => DataType::LargeUtf8, + "tdD" => DataType::Date32, + "tdm" => DataType::Date64, + "tts" => DataType::Time32(TimeUnit::Second), + "ttm" => DataType::Time32(TimeUnit::Millisecond), + "ttu" => DataType::Time64(TimeUnit::Microsecond), + "ttn" => DataType::Time64(TimeUnit::Nanosecond), + "+l" => { + let c_child = c_schema.child(0); + DataType::List(Box::new(Field::try_from(c_child)?)) + } + "+L" => { + let c_child = c_schema.child(0); + DataType::LargeList(Box::new(Field::try_from(c_child)?)) + } + "+s" => { + let fields = c_schema.children().map(Field::try_from); + DataType::Struct(fields.collect::<Result<Vec<_>>>()?) + } + other => { + return Err(ArrowError::CDataInterface(format!( + "The datatype \"{:?}\" is still not supported in Rust implementation", + other + ))) + } + }; + Ok(dtype) + } +} + +impl TryFrom<&FFI_ArrowSchema> for Field { + type Error = ArrowError; + + fn try_from(c_schema: &FFI_ArrowSchema) -> Result<Self> { + let dtype = DataType::try_from(c_schema)?; + let field = Field::new(c_schema.name(), dtype, c_schema.nullable()); + Ok(field) Review comment: https://github.com/apache/arrow-rs/issues/478 ########## File path: arrow/src/ffi.rs ########## @@ -122,66 +132,61 @@ unsafe extern "C" fn release_schema(schema: *mut FFI_ArrowSchema) { let schema = &mut *schema; // take ownership back to release it. - CString::from_raw(schema.format as *mut std::os::raw::c_char); - CString::from_raw(schema.name as *mut std::os::raw::c_char); - let private = Box::from_raw(schema.private_data as *mut SchemaPrivateData); - for child in private.children_ptr.iter() { - let _ = Box::from_raw(*child); + CString::from_raw(schema.format as *mut c_char); + if !schema.name.is_null() { + CString::from_raw(schema.name as *mut c_char); + } + if !schema.private_data.is_null() { + let private_data = Box::from_raw(schema.private_data as *mut SchemaPrivateData); + for child in private_data.children.iter() { + drop(Box::from_raw(*child)) + } + drop(private_data); } schema.release = None; } impl FFI_ArrowSchema { /// create a new [`Ffi_ArrowSchema`]. This fails if the fields' [`DataType`] is not supported. - fn try_new(field: Field) -> Result<FFI_ArrowSchema> { - let format = to_format(field.data_type())?; - let name = field.name().clone(); - - // allocate (and hold) the children - let children_vec = match field.data_type() { - DataType::List(field) => { - vec![Box::new(FFI_ArrowSchema::try_new(field.as_ref().clone())?)] - } - DataType::LargeList(field) => { - vec![Box::new(FFI_ArrowSchema::try_new(field.as_ref().clone())?)] - } - DataType::Struct(fields) => fields - .iter() - .map(|field| Ok(Box::new(FFI_ArrowSchema::try_new(field.clone())?))) - .collect::<Result<Vec<_>>>()?, - _ => vec![], - }; - // note: this cannot be done along with the above because the above is fallible and this op leaks. - let children_ptr = children_vec + pub fn try_new(format: &str, children: Vec<FFI_ArrowSchema>) -> Result<Self> { + let mut this = Self::empty(); + + // note: this op leaks. + let mut children_ptr = children .into_iter() + .map(Box::new) .map(Box::into_raw) .collect::<Box<_>>(); - let n_children = children_ptr.len() as i64; - let flags = field.is_nullable() as i64 * 2; + this.format = CString::new(format).unwrap().into_raw(); + this.release = Some(release_schema); + this.n_children = children_ptr.len() as i64; + this.children = children_ptr.as_mut_ptr(); - let mut private = Box::new(SchemaPrivateData { - field, - children_ptr, + let private_data = Box::new(SchemaPrivateData { + children: children_ptr, }); + this.private_data = Box::into_raw(private_data) as *mut c_void; - // <https://arrow.apache.org/docs/format/CDataInterface.html#c.ArrowSchema> - Ok(FFI_ArrowSchema { - format: CString::new(format).unwrap().into_raw(), - name: CString::new(name).unwrap().into_raw(), - metadata: std::ptr::null_mut(), - flags, - n_children, - children: private.children_ptr.as_mut_ptr(), - dictionary: std::ptr::null_mut(), - release: Some(release_schema), - private_data: Box::into_raw(private) as *mut ::std::os::raw::c_void, - }) + Ok(this) + } + + pub fn with_name(mut self, name: &str) -> Result<Self> { + self.name = CString::new(name).unwrap().into_raw(); + Ok(self) + } + + pub fn with_flags(mut self, flags: Flags) -> Result<Self> { + self.flags = flags.bits(); + Ok(self) } + // pub fn with_dictionary() {} + // pub fn with_metadata() {} Review comment: https://github.com/apache/arrow-rs/issues/478 -- This is an automated message from the Apache Git Service. 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