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//! Postgres rows.
use postgres_shared::rows::RowData;
use postgres_shared::stmt::Column;
use std::error::Error;
use std::fmt;
use std::sync::Arc;
#[doc(inline)]
pub use postgres_shared::rows::RowIndex;
use RowNew;
use types::{WrongType, FromSql};
/// A row from Postgres.
pub struct Row {
columns: Arc<Vec<Column>>,
data: RowData,
}
impl RowNew for Row {
fn new(columns: Arc<Vec<Column>>, data: RowData) -> Row {
Row {
columns: columns,
data: data,
}
}
}
impl Row {
/// Returns information about the columns in the row.
pub fn columns(&self) -> &[Column] {
&self.columns
}
/// Returns the number of values in the row
pub fn len(&self) -> usize {
self.columns.len()
}
/// Retrieves the contents of a field of the row.
///
/// A field can be accessed by the name or index of its column, though
/// access by index is more efficient. Rows are 0-indexed.
///
/// # Panics
///
/// Panics if the index does not reference a column or the return type is
/// not compatible with the Postgres type.
pub fn get<T, I>(&self, idx: I) -> T
where T: FromSql,
I: RowIndex + fmt::Debug
{
match self.try_get(&idx) {
Ok(Some(v)) => v,
Ok(None) => panic!("no such column {:?}", idx),
Err(e) => panic!("error retrieving row {:?}: {}", idx, e),
}
}
/// Retrieves the contents of a field of the row.
///
/// A field can be accessed by the name or index of its column, though
/// access by index is more efficient. Rows are 0-indexed.
///
/// Returns `None` if the index does not reference a column, `Some(Err(..))`
/// if there was an error converting the result value, and `Some(Ok(..))`
/// on success.
pub fn try_get<T, I>(&self, idx: I) -> Result<Option<T>, Box<Error + Sync + Send>>
where T: FromSql,
I: RowIndex
{
let idx = match idx.idx(&self.columns) {
Some(idx) => idx,
None => return Ok(None),
};
let ty = self.columns[idx].type_();
if !T::accepts(ty) {
return Err(Box::new(WrongType::new(ty.clone())));
}
T::from_sql_nullable(ty, self.data.get(idx)).map(Some)
}
}