pgx_sql_entity_graph/to_sql/
entity.rs

1/*
2Portions Copyright 2019-2021 ZomboDB, LLC.
3Portions Copyright 2021-2022 Technology Concepts & Design, Inc. <support@tcdi.com>
4
5All rights reserved.
6
7Use of this source code is governed by the MIT license that can be found in the LICENSE file.
8*/
9/*!
10
11`sql = ...` fragment related entities for Rust to SQL translation
12
13> Like all of the [`sql_entity_graph`][crate::pgx_sql_entity_graph] APIs, this is considered **internal**
14to the `pgx` framework and very subject to change between versions. While you may use this, please do it with caution.
15
16*/
17use crate::pgx_sql::PgxSql;
18use crate::to_sql::ToSqlFn;
19use crate::SqlGraphEntity;
20
21/// Represents configuration options for tuning the SQL generator.
22///
23/// When an item that can be rendered to SQL has these options at hand, they should be
24/// respected. If an item does not have them, then it is not expected that the SQL generation
25/// for those items can be modified.
26///
27/// The default configuration has `enabled` set to `true`, and `callback` to `None`, which indicates
28/// that the default SQL generation behavior will be used. These are intended to be mutually exclusive
29/// options, so `callback` should only be set if generation is enabled.
30///
31/// When `enabled` is false, no SQL is generated for the item being configured.
32///
33/// When `callback` has a value, the corresponding `ToSql` implementation should invoke the
34/// callback instead of performing their default behavior.
35#[derive(Default, Clone)]
36pub struct ToSqlConfigEntity {
37    pub enabled: bool,
38    pub callback: Option<ToSqlFn>,
39    pub content: Option<&'static str>,
40}
41impl ToSqlConfigEntity {
42    /// Helper used to implement traits (`Eq`, `Ord`, etc) despite `ToSqlFn` not
43    /// having an implementation for them.
44    #[inline]
45    fn fields(&self) -> (bool, Option<&str>, Option<usize>) {
46        (self.enabled, self.content, self.callback.map(|f| f as usize))
47    }
48    /// Given a SqlGraphEntity, this function converts it to SQL based on the current configuration.
49    ///
50    /// If the config overrides the default behavior (i.e. using the `ToSql` trait), then `Some(eyre::Result)`
51    /// is returned. If the config does not override the default behavior, then `None` is returned. This can
52    /// be used to dispatch SQL generation in a single line, e.g.:
53    ///
54    /// ```rust,ignore
55    /// config.to_sql(entity, context).unwrap_or_else(|| entity.to_sql(context))?
56    /// ```
57    pub fn to_sql(
58        &self,
59        entity: &SqlGraphEntity,
60        context: &PgxSql,
61    ) -> Option<eyre::Result<String>> {
62        use eyre::{eyre, WrapErr};
63
64        if !self.enabled {
65            return Some(Ok(format!(
66                "\n\
67                {sql_anchor_comment}\n\
68                -- Skipped due to `#[pgx(sql = false)]`\n",
69                sql_anchor_comment = entity.sql_anchor_comment(),
70            )));
71        }
72
73        if let Some(content) = self.content {
74            let module_pathname = context.get_module_pathname();
75
76            let content = content.replace("@MODULE_PATHNAME@", &module_pathname);
77
78            return Some(Ok(format!(
79                "\n\
80                {sql_anchor_comment}\n\
81                {content}\n\
82            ",
83                content = content,
84                sql_anchor_comment = entity.sql_anchor_comment()
85            )));
86        }
87
88        if let Some(callback) = self.callback {
89            let content = callback(entity, context)
90                .map_err(|e| eyre!(e))
91                .wrap_err("Failed to run specified `#[pgx(sql = path)] function`");
92            return match content {
93                Ok(content) => {
94                    let module_pathname = &context.get_module_pathname();
95
96                    let content = content.replace("@MODULE_PATHNAME@", &module_pathname);
97
98                    Some(Ok(format!(
99                        "\n\
100                        {sql_anchor_comment}\n\
101                        {content}\
102                    ",
103                        content = content,
104                        sql_anchor_comment = entity.sql_anchor_comment(),
105                    )))
106                }
107                Err(e) => Some(Err(e)),
108            };
109        }
110
111        None
112    }
113}
114
115impl std::cmp::PartialOrd for ToSqlConfigEntity {
116    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
117        Some(self.cmp(&other))
118    }
119}
120impl std::cmp::Ord for ToSqlConfigEntity {
121    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
122        self.fields().cmp(&other.fields())
123    }
124}
125impl std::cmp::PartialEq for ToSqlConfigEntity {
126    fn eq(&self, other: &Self) -> bool {
127        self.fields() == other.fields()
128    }
129}
130impl std::cmp::Eq for ToSqlConfigEntity {}
131impl std::hash::Hash for ToSqlConfigEntity {
132    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
133        self.fields().hash(state);
134    }
135}
136impl std::fmt::Debug for ToSqlConfigEntity {
137    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
138        let (enabled, content, callback) = self.fields();
139        f.debug_struct("ToSqlConfigEntity")
140            .field("enabled", &enabled)
141            .field("callback", &callback)
142            .field("content", &content)
143            .finish()
144    }
145}
pgx_sql_entity_graph/to_sql/entity.rs

pgx_sql_entity_graph/to_sql/
entity.rs
