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use super::{
    arrow::{datatypes::SchemaRef, record_batch::RecordBatch},
    Statement,
};

/// An handle for the resulting RecordBatch of a query.
#[must_use = "Arrow is lazy and will do nothing unless consumed"]
pub struct Arrow<'stmt> {
    pub(crate) stmt: Option<&'stmt Statement<'stmt>>,
}

impl<'stmt> Arrow<'stmt> {
    #[inline]
    pub(crate) fn new(stmt: &'stmt Statement<'stmt>) -> Arrow<'stmt> {
        Arrow { stmt: Some(stmt) }
    }

    /// return arrow schema
    #[inline]
    pub fn get_schema(&self) -> SchemaRef {
        self.stmt.unwrap().stmt.schema()
    }
}

impl<'stmt> Iterator for Arrow<'stmt> {
    type Item = RecordBatch;

    fn next(&mut self) -> Option<Self::Item> {
        Some(RecordBatch::from(&self.stmt?.step()?))
    }
}