137 lines
2.9 KiB
Rust
137 lines
2.9 KiB
Rust
use std::{
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char::ParseCharError,
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convert::Infallible,
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fmt::Display,
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num::{ParseFloatError, ParseIntError},
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str::ParseBoolError,
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};
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use serde::{de::DeserializeOwned, Serialize};
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use crate::ID;
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/// Cursor type
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///
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/// A custom scalar that serializes as a string.
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/// <https://relay.dev/graphql/connections.htm#sec-Cursor>
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pub trait CursorType: Sized {
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/// Error type for `decode_cursor`.
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type Error: Display;
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/// Decode cursor from string.
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fn decode_cursor(s: &str) -> Result<Self, Self::Error>;
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/// Encode cursor to string.
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fn encode_cursor(&self) -> String;
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}
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macro_rules! cursor_type_int_impl {
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($($t:ty)*) => {$(
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impl CursorType for $t {
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type Error = ParseIntError;
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fn decode_cursor(s: &str) -> Result<Self, Self::Error> {
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s.parse()
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}
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fn encode_cursor(&self) -> String {
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self.to_string()
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}
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}
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)*}
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}
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cursor_type_int_impl! { isize i8 i16 i32 i64 i128 usize u8 u16 u32 u64 u128 }
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impl CursorType for f32 {
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type Error = ParseFloatError;
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fn decode_cursor(s: &str) -> Result<Self, Self::Error> {
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s.parse()
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}
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fn encode_cursor(&self) -> String {
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self.to_string()
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}
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}
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impl CursorType for f64 {
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type Error = ParseFloatError;
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fn decode_cursor(s: &str) -> Result<Self, Self::Error> {
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s.parse()
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}
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fn encode_cursor(&self) -> String {
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self.to_string()
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}
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}
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impl CursorType for char {
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type Error = ParseCharError;
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fn decode_cursor(s: &str) -> Result<Self, Self::Error> {
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s.parse()
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}
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fn encode_cursor(&self) -> String {
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self.to_string()
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}
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}
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impl CursorType for bool {
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type Error = ParseBoolError;
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fn decode_cursor(s: &str) -> Result<Self, Self::Error> {
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s.parse()
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}
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fn encode_cursor(&self) -> String {
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self.to_string()
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}
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}
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impl CursorType for String {
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type Error = Infallible;
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fn decode_cursor(s: &str) -> Result<Self, Self::Error> {
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Ok(s.to_string())
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}
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fn encode_cursor(&self) -> String {
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self.clone()
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}
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}
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impl CursorType for ID {
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type Error = Infallible;
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fn decode_cursor(s: &str) -> Result<Self, Self::Error> {
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Ok(s.to_string().into())
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}
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fn encode_cursor(&self) -> String {
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self.to_string()
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}
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}
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/// A opaque cursor that encode/decode the value to base64
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pub struct OpaqueCursor<T>(T);
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impl<T> CursorType for OpaqueCursor<T>
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where
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T: Serialize + DeserializeOwned,
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{
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type Error = Box<dyn std::error::Error + Send + Sync>;
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fn decode_cursor(s: &str) -> Result<Self, Self::Error> {
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let data = base64::decode_config(s, base64::URL_SAFE_NO_PAD)?;
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Ok(Self(serde_json::from_slice(&data)?))
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}
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fn encode_cursor(&self) -> String {
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let value = serde_json::to_vec(&self.0).unwrap_or_default();
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base64::encode_config(value, base64::URL_SAFE_NO_PAD)
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}
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}
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