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| 1 | +// Licensed to the Apache Software Foundation (ASF) under one |
| 2 | +// or more contributor license agreements. See the NOTICE file |
| 3 | +// distributed with this work for additional information |
| 4 | +// regarding copyright ownership. The ASF licenses this file |
| 5 | +// to you under the Apache License, Version 2.0 (the |
| 6 | +// "License"); you may not use this file except in compliance |
| 7 | +// with the License. You may obtain a copy of the License at |
| 8 | +// |
| 9 | +// http://www.apache.org/licenses/LICENSE-2.0 |
| 10 | +// |
| 11 | +// Unless required by applicable law or agreed to in writing, |
| 12 | +// software distributed under the License is distributed on an |
| 13 | +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| 14 | +// KIND, either express or implied. See the License for the |
| 15 | +// specific language governing permissions and limitations |
| 16 | +// under the License. |
| 17 | + |
| 18 | +use crate::common::df_schema::PyDFSchema; |
| 19 | +use datafusion_expr::EmptyRelation; |
| 20 | +use pyo3::prelude::*; |
| 21 | +use std::fmt::{self, Display, Formatter}; |
| 22 | + |
| 23 | +#[pyclass(name = "EmptyRelation", module = "datafusion.expr", subclass)] |
| 24 | +#[derive(Clone)] |
| 25 | +pub struct PyEmptyRelation { |
| 26 | + empty: EmptyRelation, |
| 27 | +} |
| 28 | + |
| 29 | +impl From<PyEmptyRelation> for EmptyRelation { |
| 30 | + fn from(empty_relation: PyEmptyRelation) -> Self { |
| 31 | + empty_relation.empty |
| 32 | + } |
| 33 | +} |
| 34 | + |
| 35 | +impl From<EmptyRelation> for PyEmptyRelation { |
| 36 | + fn from(empty: EmptyRelation) -> PyEmptyRelation { |
| 37 | + PyEmptyRelation { empty } |
| 38 | + } |
| 39 | +} |
| 40 | + |
| 41 | +impl Display for PyEmptyRelation { |
| 42 | + fn fmt(&self, f: &mut Formatter) -> fmt::Result { |
| 43 | + write!( |
| 44 | + f, |
| 45 | + "Empty Relation |
| 46 | + \nProduce One Row: {:?} |
| 47 | + \nSchema: {:?}", |
| 48 | + &self.empty.produce_one_row, &self.empty.schema |
| 49 | + ) |
| 50 | + } |
| 51 | +} |
| 52 | + |
| 53 | +#[pymethods] |
| 54 | +impl PyEmptyRelation { |
| 55 | + fn produce_one_row(&self) -> PyResult<bool> { |
| 56 | + Ok(self.empty.produce_one_row) |
| 57 | + } |
| 58 | + |
| 59 | + /// Resulting Schema for this `EmptyRelation` node instance |
| 60 | + fn schema(&self) -> PyResult<PyDFSchema> { |
| 61 | + Ok((*self.empty.schema).clone().into()) |
| 62 | + } |
| 63 | + |
| 64 | + /// Get a String representation of this column |
| 65 | + fn __repr__(&self) -> String { |
| 66 | + format!("{}", self) |
| 67 | + } |
| 68 | + |
| 69 | + fn __name__(&self) -> PyResult<String> { |
| 70 | + Ok("EmptyRelation".to_string()) |
| 71 | + } |
| 72 | +} |
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