mentat/query-projector/src/projectors/mod.rs

// Copyright 2018 Mozilla
//
// Licensed 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 super::{rusqlite, Element, QueryOutput, Rows, Schema};

use query_projector_traits::errors::Result;

pub trait Projector {
    fn project<'stmt, 's>(
        &self,
        schema: &Schema,
        sqlite: &'s rusqlite::Connection,
        rows: Rows<'stmt>,
    ) -> Result<QueryOutput>;
    fn columns<'s>(&'s self) -> Box<dyn Iterator<Item = &Element> + 's>;
}

mod constant;
mod pull_two_stage;
mod simple;

pub use self::constant::ConstantProjector;

pub(crate) use self::simple::{CollProjector, RelProjector, ScalarProjector, TupleProjector};

pub(crate) use self::pull_two_stage::{
    CollTwoStagePullProjector, RelTwoStagePullProjector, ScalarTwoStagePullProjector,
    TupleTwoStagePullProjector,
};