Coverage Report

Created: 2024-10-13 08:39

/Users/andrewlamb/Software/datafusion/datafusion/expr/src/var_provider.rs
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// Licensed to the Apache Software Foundation (ASF) under one
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// or more contributor license agreements.  See the NOTICE file
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// distributed with this work for additional information
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// regarding copyright ownership.  The ASF licenses this file
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// to you under the Apache License, Version 2.0 (the
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// "License"); you may not use this file except in compliance
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// with the License.  You may obtain a copy of the License at
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//
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//   http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing,
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// software distributed under the License is distributed on an
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// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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// KIND, either express or implied.  See the License for the
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// specific language governing permissions and limitations
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// under the License.
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//! Variable provider
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use arrow::datatypes::DataType;
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use datafusion_common::{Result, ScalarValue};
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/// Variable type, system/user defined
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#[derive(Debug, Clone, PartialEq, Eq, Hash)]
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pub enum VarType {
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    /// System variable, like @@version
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    System,
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    /// User defined variable, like @name
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    UserDefined,
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}
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/// A var provider for `@variable` and `@@variable` runtime values.
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pub trait VarProvider: std::fmt::Debug {
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    /// Get variable value
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    fn get_value(&self, var_names: Vec<String>) -> Result<ScalarValue>;
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    /// Return the type of the given variable
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    fn get_type(&self, var_names: &[String]) -> Option<DataType>;
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}
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pub fn is_system_variables(variable_names: &[String]) -> bool {
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    !variable_names.is_empty() && variable_names[0].get(0..2) == Some("@@")
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}
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#[cfg(test)]
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mod test {
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    use super::*;
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    #[test]
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    fn test_is_system_variables() {
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        assert!(!is_system_variables(&["N".into(), "\"\"".into()]));
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        assert!(is_system_variables(&["@@D".into(), "F".into(), "J".into()]));
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        assert!(!is_system_variables(&[
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            "J".into(),
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            "@@F".into(),
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            "K".into()
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        ]));
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        assert!(!is_system_variables(&[]));
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        assert!(is_system_variables(&[
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            "@@longvariablenamethatIdontknowhwyanyonewoulduse".into()
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        ]));
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        assert!(!is_system_variables(&["@F".into()]));
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    }
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}