1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
// 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::fmt::{self, Display, Formatter};
use datafusion::logical_expr::EmptyRelation;
use pyo3::IntoPyObjectExt;
use pyo3::prelude::*;
use super::logical_node::LogicalNode;
use crate::common::df_schema::PyDFSchema;
use crate::sql::logical::PyLogicalPlan;
#[pyclass(
from_py_object,
frozen,
name = "EmptyRelation",
module = "datafusion.expr",
subclass
)]
#[derive(Clone)]
pub struct PyEmptyRelation {
empty: EmptyRelation,
}
impl From<PyEmptyRelation> for EmptyRelation {
fn from(empty_relation: PyEmptyRelation) -> Self {
empty_relation.empty
}
}
impl From<EmptyRelation> for PyEmptyRelation {
fn from(empty: EmptyRelation) -> PyEmptyRelation {
PyEmptyRelation { empty }
}
}
impl Display for PyEmptyRelation {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
write!(
f,
"Empty Relation
Produce One Row: {:?}
Schema: {:?}",
&self.empty.produce_one_row, &self.empty.schema
)
}
}
#[pymethods]
impl PyEmptyRelation {
fn produce_one_row(&self) -> PyResult<bool> {
Ok(self.empty.produce_one_row)
}
/// Resulting Schema for this `EmptyRelation` node instance
fn schema(&self) -> PyResult<PyDFSchema> {
Ok((*self.empty.schema).clone().into())
}
/// Get a String representation of this column
fn __repr__(&self) -> String {
format!("{self}")
}
fn __name__(&self) -> PyResult<String> {
Ok("EmptyRelation".to_string())
}
}
impl LogicalNode for PyEmptyRelation {
fn inputs(&self) -> Vec<PyLogicalPlan> {
// table scans are leaf nodes and do not have inputs
vec![]
}
fn to_variant<'py>(&self, py: Python<'py>) -> PyResult<Bound<'py, PyAny>> {
self.clone().into_bound_py_any(py)
}
}