sqlx_core/
arguments.rs

1//! Types and traits for passing arguments to SQL queries.
2
3use crate::database::Database;
4use crate::encode::Encode;
5use crate::error::BoxDynError;
6use crate::types::Type;
7use std::fmt::{self, Write};
8
9/// A tuple of arguments to be sent to the database.
10// This lint is designed for general collections, but `Arguments` is not meant to be as such.
11#[allow(clippy::len_without_is_empty)]
12pub trait Arguments: Send + Sized + Default {
13    type Database: Database;
14
15    /// Reserves the capacity for at least `additional` more values (of `size` total bytes) to
16    /// be added to the arguments without a reallocation.
17    fn reserve(&mut self, additional: usize, size: usize);
18
19    /// Add the value to the end of the arguments.
20    fn add<'t, T>(&mut self, value: T) -> Result<(), BoxDynError>
21    where
22        T: Encode<'t, Self::Database> + Type<Self::Database>;
23
24    /// The number of arguments that were already added.
25    fn len(&self) -> usize;
26
27    fn format_placeholder<W: Write>(&self, writer: &mut W) -> fmt::Result {
28        writer.write_str("?")
29    }
30}
31
32pub trait IntoArguments<DB: Database>: Sized + Send {
33    fn into_arguments(self) -> <DB as Database>::Arguments;
34}
35
36// NOTE: required due to lack of lazy normalization
37#[macro_export]
38macro_rules! impl_into_arguments_for_arguments {
39    ($Arguments:path) => {
40        impl
41            $crate::arguments::IntoArguments<<$Arguments as $crate::arguments::Arguments>::Database>
42            for $Arguments
43        {
44            fn into_arguments(self) -> $Arguments {
45                self
46            }
47        }
48    };
49}
50
51/// used by the query macros to prevent supernumerary `.bind()` calls
52pub struct ImmutableArguments<DB: Database>(pub <DB as Database>::Arguments);
53
54impl<DB: Database> IntoArguments<DB> for ImmutableArguments<DB> {
55    fn into_arguments(self) -> <DB as Database>::Arguments {
56        self.0
57    }
58}
sqlx_core/arguments.rs

sqlx_core/
arguments.rs
