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Diffstat (limited to 'third_party/rust/askama/src')
-rw-r--r-- | third_party/rust/askama/src/lib.rs | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/third_party/rust/askama/src/lib.rs b/third_party/rust/askama/src/lib.rs new file mode 100644 index 0000000000..ccfddc8fb3 --- /dev/null +++ b/third_party/rust/askama/src/lib.rs @@ -0,0 +1,185 @@ +//! Askama implements a type-safe compiler for Jinja-like templates. +//! It lets you write templates in a Jinja-like syntax, +//! which are linked to a `struct` defining the template context. +//! This is done using a custom derive implementation (implemented +//! in [`askama_derive`](https://crates.io/crates/askama_derive)). +//! +//! For feature highlights and a quick start, please review the +//! [README](https://github.com/djc/askama/blob/main/README.md). +//! +//! The primary documentation for this crate now lives in +//! [the book](https://djc.github.io/askama/). +//! +//! # Creating Askama templates +//! +//! An Askama template is a `struct` definition which provides the template +//! context combined with a UTF-8 encoded text file (or inline source, see +//! below). Askama can be used to generate any kind of text-based format. +//! The template file's extension may be used to provide content type hints. +//! +//! A template consists of **text contents**, which are passed through as-is, +//! **expressions**, which get replaced with content while being rendered, and +//! **tags**, which control the template's logic. +//! The template syntax is very similar to [Jinja](http://jinja.pocoo.org/), +//! as well as Jinja-derivatives like [Twig](http://twig.sensiolabs.org/) or +//! [Tera](https://github.com/Keats/tera). +//! +//! ## The `template()` attribute +//! +//! Askama works by generating one or more trait implementations for any +//! `struct` type decorated with the `#[derive(Template)]` attribute. The +//! code generation process takes some options that can be specified through +//! the `template()` attribute. The following sub-attributes are currently +//! recognized: +//! +//! * `path` (as `path = "foo.html"`): sets the path to the template file. The +//! path is interpreted as relative to the configured template directories +//! (by default, this is a `templates` directory next to your `Cargo.toml`). +//! The file name extension is used to infer an escape mode (see below). In +//! web framework integrations, the path's extension may also be used to +//! infer the content type of the resulting response. +//! Cannot be used together with `source`. +//! * `source` (as `source = "{{ foo }}"`): directly sets the template source. +//! This can be useful for test cases or short templates. The generated path +//! is undefined, which generally makes it impossible to refer to this +//! template from other templates. If `source` is specified, `ext` must also +//! be specified (see below). Cannot be used together with `path`. +//! * `ext` (as `ext = "txt"`): lets you specify the content type as a file +//! extension. This is used to infer an escape mode (see below), and some +//! web framework integrations use it to determine the content type. +//! Cannot be used together with `path`. +//! * `print` (as `print = "code"`): enable debugging by printing nothing +//! (`none`), the parsed syntax tree (`ast`), the generated code (`code`) +//! or `all` for both. The requested data will be printed to stdout at +//! compile time. +//! * `escape` (as `escape = "none"`): override the template's extension used for +//! the purpose of determining the escaper for this template. See the section +//! on configuring custom escapers for more information. +//! * `syntax` (as `syntax = "foo"`): set the syntax name for a parser defined +//! in the configuration file. The default syntax , "default", is the one +//! provided by Askama. + +#![forbid(unsafe_code)] +#![deny(elided_lifetimes_in_paths)] +#![deny(unreachable_pub)] + +pub use askama_shared as shared; + +pub use askama_escape::{Html, Text}; + +/// Main `Template` trait; implementations are generally derived +/// +/// If you need an object-safe template, use [`DynTemplate`]. +pub trait Template { + /// Helper method which allocates a new `String` and renders into it + fn render(&self) -> Result<String> { + let mut buf = String::with_capacity(Self::SIZE_HINT); + self.render_into(&mut buf)?; + Ok(buf) + } + + /// Renders the template to the given `writer` buffer + fn render_into(&self, writer: &mut (impl std::fmt::Write + ?Sized)) -> Result<()>; + + /// The template's extension, if provided + const EXTENSION: Option<&'static str>; + + /// Provides a conservative estimate of the expanded length of the rendered template + const SIZE_HINT: usize; + + /// The MIME type (Content-Type) of the data that gets rendered by this Template + const MIME_TYPE: &'static str; +} + +/// Object-safe wrapper trait around [`Template`] implementers +/// +/// This trades reduced performance (mostly due to writing into `dyn Write`) for object safety. +pub trait DynTemplate { + /// Helper method which allocates a new `String` and renders into it + fn dyn_render(&self) -> Result<String>; + + /// Renders the template to the given `writer` buffer + fn dyn_render_into(&self, writer: &mut dyn std::fmt::Write) -> Result<()>; + + /// Helper function to inspect the template's extension + fn extension(&self) -> Option<&'static str>; + + /// Provides a conservative estimate of the expanded length of the rendered template + fn size_hint(&self) -> usize; + + /// The MIME type (Content-Type) of the data that gets rendered by this Template + fn mime_type(&self) -> &'static str; +} + +impl<T: Template> DynTemplate for T { + fn dyn_render(&self) -> Result<String> { + <Self as Template>::render(self) + } + + fn dyn_render_into(&self, writer: &mut dyn std::fmt::Write) -> Result<()> { + <Self as Template>::render_into(self, writer) + } + + fn extension(&self) -> Option<&'static str> { + Self::EXTENSION + } + + fn size_hint(&self) -> usize { + Self::SIZE_HINT + } + + fn mime_type(&self) -> &'static str { + Self::MIME_TYPE + } +} + +pub use crate::shared::filters; +pub use crate::shared::helpers; +pub use crate::shared::{read_config_file, Error, MarkupDisplay, Result}; +pub use askama_derive::*; + +#[deprecated(since = "0.11.1", note = "The only function in this mod is deprecated")] +pub mod mime { + #[cfg(all(feature = "mime_guess", feature = "mime"))] + #[deprecated(since = "0.11.1", note = "Use Template::MIME_TYPE instead")] + pub use crate::shared::extension_to_mime_type; +} + +/// Old build script helper to rebuild crates if contained templates have changed +/// +/// This function is now deprecated and does nothing. +#[deprecated( + since = "0.8.1", + note = "file-level dependency tracking is handled automatically without build script" +)] +pub fn rerun_if_templates_changed() {} + +#[cfg(test)] +mod tests { + use super::{DynTemplate, Template}; + + #[test] + fn dyn_template() { + struct Test; + impl Template for Test { + fn render_into( + &self, + writer: &mut (impl std::fmt::Write + ?Sized), + ) -> askama_shared::Result<()> { + Ok(writer.write_str("test")?) + } + + const EXTENSION: Option<&'static str> = Some("txt"); + + const SIZE_HINT: usize = 4; + + const MIME_TYPE: &'static str = "text/plain; charset=utf-8"; + } + + fn render(t: &dyn DynTemplate) -> String { + t.dyn_render().unwrap() + } + + assert_eq!(render(&Test), "test"); + } +} |