mas_templates/
macros.rs

1// Copyright 2024, 2025 New Vector Ltd.
2// Copyright 2021-2024 The Matrix.org Foundation C.I.C.
3//
4// SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
5// Please see LICENSE files in the repository root for full details.
6
7/// Count the number of tokens. Used to have a fixed-sized array for the
8/// templates list.
9macro_rules! count {
10    () => (0_usize);
11    ( $x:tt $($xs:tt)* ) => (1_usize + count!($($xs)*));
12}
13
14/// Macro that helps generating helper function that renders a specific template
15/// with a strongly-typed context. It also register the template in a static
16/// array to help detecting missing templates at startup time.
17///
18/// The syntax looks almost like a function to confuse syntax highlighter as
19/// little as possible.
20#[macro_export]
21macro_rules! register_templates {
22    {
23        $(
24            extra = { $( $extra_template:expr ),* $(,)? };
25        )?
26
27        $(
28            // Match any attribute on the function, such as #[doc], #[allow(dead_code)], etc.
29            $( #[ $attr:meta ] )*
30            // The function name
31            pub fn $name:ident
32                // Optional list of generics. Taken from
33                // https://newbedev.com/rust-macro-accepting-type-with-generic-parameters
34                // For sample rendering, we also require a 'sample' generic parameter to be provided,
35                // using #[sample(Type)] attribute syntax
36                $(< $( #[sample( $generic_default:tt )] $lt:tt $( : $clt:tt $(+ $dlt:tt )* )? ),+ >)?
37                // Type of context taken by the template
38                ( $param:ty )
39            {
40                // The name of the template file
41                $template:expr
42            }
43        )*
44    } => {
45        /// List of registered templates
46        static TEMPLATES: [&'static str; count!( $( $template )* )] = [ $( $template, )* ];
47
48        impl Templates {
49            $(
50                $(#[$attr])?
51                ///
52                /// # Errors
53                ///
54                /// Returns an error if the template fails to render.
55                pub fn $name
56                    $(< $( $lt $( : $clt $(+ $dlt )* )? ),+ >)?
57                    (&self, context: &$param)
58                -> Result<String, TemplateError> {
59                    let ctx = ::minijinja::value::Value::from_serialize(context);
60
61                    let env = self.environment.load();
62                    let tmpl = env.get_template($template)
63                        .map_err(|source| TemplateError::Missing { template: $template, source })?;
64                    tmpl.render(ctx)
65                        .map_err(|source| TemplateError::Render { template: $template, source })
66                }
67            )*
68        }
69
70        /// Helps rendering each template with sample data
71        pub mod check {
72            use super::*;
73
74            /// Check and render all templates with all samples.
75            ///
76            /// Returns the sample renders. The keys in the map are the template names.
77            ///
78            /// # Errors
79            ///
80            /// Returns an error if any template fails to render with any of the sample.
81            pub(crate) fn all<R: Rng + Clone>(templates: &Templates, now: chrono::DateTime<chrono::Utc>, rng: &R) -> anyhow::Result<::std::collections::BTreeMap<(&'static str, SampleIdentifier), String>> {
82                let mut out = ::std::collections::BTreeMap::new();
83                // TODO shouldn't the Rng be independent for each render?
84                $(
85                    {
86                        let mut rng = rng.clone();
87                        out.extend(
88                            $name $(::< _ $( , $generic_default ),* >)? (templates, now, &mut rng)?
89                                .into_iter()
90                                .map(|(sample_identifier, rendered)| (($template, sample_identifier), rendered))
91                        );
92                    }
93                )*
94
95                Ok(out)
96            }
97
98            $(
99                #[doc = concat!("Render the `", $template, "` template with sample contexts")]
100                ///
101                /// Returns the sample renders.
102                ///
103                /// # Errors
104                ///
105                /// Returns an error if the template fails to render with any of the sample.
106                pub(crate) fn $name
107                    < __R: Rng + Clone $( , $( $lt $( : $clt $(+ $dlt )* + TemplateContext )? ),+ )? >
108                    (templates: &Templates, now: chrono::DateTime<chrono::Utc>, rng: &mut __R)
109                -> anyhow::Result<BTreeMap<SampleIdentifier, String>> {
110                    let locales = templates.translator().available_locales();
111                    let samples: BTreeMap<SampleIdentifier, $param > = TemplateContext::sample(now, rng, &locales);
112
113                    let name = $template;
114                    let mut out = BTreeMap::new();
115                    for (sample_identifier, sample) in samples {
116                        let context = serde_json::to_value(&sample)?;
117                        ::tracing::info!(name, %context, "Rendering template");
118                        let rendered = templates. $name (&sample)
119                            .with_context(|| format!("Failed to render sample template {name:?}-{sample_identifier:?} with context {context}"))?;
120                        out.insert(sample_identifier, rendered);
121                    }
122
123                    Ok(out)
124                }
125            )*
126        }
127    };
128}
mas_templates/macros.rs

mas_templates/
macros.rs
