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/*
Portions Copyright 2019-2021 ZomboDB, LLC.
Portions Copyright 2021-2022 Technology Concepts & Design, Inc. <support@tcdi.com>
All rights reserved.
Use of this source code is governed by the MIT license that can be found in the LICENSE file.
*/
//! Helper trait for the `#[derive(PostgresType)]` proc macro for overriding custom Postgres type
//! input/output functions.
//!
//! The default implementations use `serde_json` to serialize a custom type to human-readable strings,
//! and `serde_cbor` to serialize internally as a `varlena *` for storage on disk.
use crate::*;
/// `#[derive(Copy, Clone, PostgresType)]` types need to implement this trait to provide the text
/// input/output functions for that type
pub trait PgVarlenaInOutFuncs {
/// Given a string representation of `Self`, parse it into a `PgVarlena<Self>`.
///
/// It is expected that malformed input will raise an `error!()` or `panic!()`
fn input(input: &core::ffi::CStr) -> PgVarlena<Self>
where
Self: Copy + Sized;
/// Convert `Self` into text by writing to the supplied `StringInfo` buffer
fn output(&self, buffer: &mut StringInfo);
/// If PostgreSQL calls the conversion function with NULL as an argument, what
/// error message should be generated?
const NULL_ERROR_MESSAGE: Option<&'static str> = None;
}
/// `#[derive(Serialize, Deserialize, PostgresType)]` types may implement this trait if they prefer
/// a textual representation that isn't JSON
pub trait InOutFuncs {
/// Given a string representation of `Self`, parse it into `Self`.
///
/// It is expected that malformed input will raise an `error!()` or `panic!()`
fn input(input: &core::ffi::CStr) -> Self
where
Self: Sized;
/// Convert `Self` into text by writing to the supplied `StringInfo` buffer
fn output(&self, buffer: &mut StringInfo);
/// If PostgreSQL calls the conversion function with NULL as an argument, what
/// error message should be generated?
const NULL_ERROR_MESSAGE: Option<&'static str> = None;
}
/// Automatically implemented for `#[derive(Serialize, Deserialize, PostgresType)]` types that do
/// **not** also have the `#[inoutfuncs]` attribute macro
pub trait JsonInOutFuncs<'de>: serde::de::Deserialize<'de> + serde::ser::Serialize {
/// Uses `serde_json` to deserialize the input, which is assumed to be JSON
fn input(input: &'de core::ffi::CStr) -> Self {
serde_json::from_str(input.to_str().expect("text input is not valid UTF8"))
.expect("failed to deserialize json")
}
/// Users `serde_json` to serialize `Self` into JSON
fn output(&self, buffer: &mut StringInfo)
where
Self: serde::ser::Serialize,
{
serde_json::to_writer(buffer, self).expect("failed to serialize to json")
}
/// If PostgreSQL calls the conversion function with NULL as an argument, what
/// error message should be generated?
const NULL_ERROR_MESSAGE: Option<&'static str> = None;
}