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// Copyright 2020 ZomboDB, LLC <zombodb@gmail.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: &std::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); } /// `#[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: &std::ffi::CStr) -> Self where Self: Sized; /// Convert `Self` into text by writing to the supplied `StringInfo` buffer fn output(&self, buffer: &mut StringInfo); } /// 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 std::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") } }