pgrx_sql_entity_graph/pg_extern/
cast.rs

1//LICENSE Portions Copyright 2019-2021 ZomboDB, LLC.
2//LICENSE
3//LICENSE Portions Copyright 2021-2023 Technology Concepts & Design, Inc.
4//LICENSE
5//LICENSE Portions Copyright 2023-2023 PgCentral Foundation, Inc. <contact@pgcentral.org>
6//LICENSE
7//LICENSE All rights reserved.
8//LICENSE
9//LICENSE Use of this source code is governed by the MIT license that can be found in the LICENSE file.
10/*!
11
12`#[pg_cast]` related macro expansion for Rust to SQL translation
13
14> Like all of the [`sql_entity_graph`][crate] APIs, this is considered **internal**
15> to the `pgrx` framework and very subject to change between versions. While you may use this, please do it with caution.
16
17*/
18use proc_macro2::TokenStream as TokenStream2;
19use quote::{ToTokens, TokenStreamExt, quote};
20use syn::Path;
21
22/// A parsed `#[pg_cast]` operator.
23///
24/// It is created during [`PgExtern`](crate::PgExtern) parsing.
25#[derive(Debug, Clone, Default)]
26pub enum PgCast {
27    #[default]
28    Default,
29    Assignment,
30    Implicit,
31}
32
33pub type InvalidCastStyle = Path;
34
35impl TryFrom<Path> for PgCast {
36    type Error = InvalidCastStyle;
37
38    fn try_from(path: Path) -> Result<Self, Self::Error> {
39        if path.is_ident("implicit") {
40            Ok(Self::Implicit)
41        } else if path.is_ident("assignment") {
42            Ok(Self::Assignment)
43        } else {
44            Err(path)
45        }
46    }
47}
48
49impl ToTokens for PgCast {
50    fn to_tokens(&self, tokens: &mut TokenStream2) {
51        let quoted = match self {
52            PgCast::Default => quote! {
53                ::pgrx::pgrx_sql_entity_graph::PgCastEntity::Default
54            },
55            PgCast::Assignment => quote! {
56                ::pgrx::pgrx_sql_entity_graph::PgCastEntity::Assignment
57            },
58            PgCast::Implicit => quote! {
59                ::pgrx::pgrx_sql_entity_graph::PgCastEntity::Implicit
60            },
61        };
62        tokens.append_all(quoted);
63    }
64}
65
66impl PgCast {
67    pub fn section_len_tokens(&self) -> TokenStream2 {
68        quote! { ::pgrx::pgrx_sql_entity_graph::section::u8_len() }
69    }
70
71    pub fn section_writer_tokens(&self, writer: TokenStream2) -> TokenStream2 {
72        match self {
73            PgCast::Default => quote! {
74                #writer.u8(::pgrx::pgrx_sql_entity_graph::section::OPERATOR_CAST_DEFAULT)
75            },
76            PgCast::Assignment => quote! {
77                #writer.u8(::pgrx::pgrx_sql_entity_graph::section::OPERATOR_CAST_ASSIGNMENT)
78            },
79            PgCast::Implicit => quote! {
80                #writer.u8(::pgrx::pgrx_sql_entity_graph::section::OPERATOR_CAST_IMPLICIT)
81            },
82        }
83    }
84}
pgrx_sql_entity_graph/pg_extern/cast.rs

pgrx_sql_entity_graph/pg_extern/
cast.rs
