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#![cfg_attr(feature = "cargo-clippy", allow(unused_parens))]
#![forbid(unsafe_code)]
#![deny(elided_lifetimes_in_paths)]
#![deny(unreachable_pub)]
use std::fmt;
pub use askama_escape::MarkupDisplay;
mod error;
pub use crate::error::{Error, Result};
pub mod filters;
pub mod helpers;
/// Main `Template` trait; implementations are generally derived
///
/// If you need an object-safe template, use [`DynTemplate`].
pub trait Template: fmt::Display {
/// 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` fmt buffer
fn render_into(&self, writer: &mut (impl std::fmt::Write + ?Sized)) -> Result<()>;
/// Renders the template to the given `writer` io buffer
#[inline]
fn write_into(&self, writer: &mut (impl std::io::Write + ?Sized)) -> std::io::Result<()> {
writer.write_fmt(format_args!("{}", self))
}
/// 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` fmt buffer
fn dyn_render_into(&self, writer: &mut dyn std::fmt::Write) -> Result<()>;
/// Renders the template to the given `writer` io buffer
fn dyn_write_into(&self, writer: &mut dyn std::io::Write) -> std::io::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)
}
#[inline]
fn dyn_write_into(&self, writer: &mut dyn std::io::Write) -> std::io::Result<()> {
writer.write_fmt(format_args!("{}", self))
}
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
}
}
impl fmt::Display for dyn DynTemplate {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.dyn_render_into(f).map_err(|_| ::std::fmt::Error {})
}
}
#[cfg(test)]
#[allow(clippy::blacklisted_name)]
mod tests {
use std::fmt;
use super::*;
use crate::{DynTemplate, Template};
#[test]
fn dyn_template() {
struct Test;
impl Template for Test {
fn render_into(&self, writer: &mut (impl std::fmt::Write + ?Sized)) -> 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";
}
impl fmt::Display for Test {
#[inline]
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.render_into(f).map_err(|_| fmt::Error {})
}
}
fn render(t: &dyn DynTemplate) -> String {
t.dyn_render().unwrap()
}
let test = &Test as &dyn DynTemplate;
assert_eq!(render(test), "test");
assert_eq!(test.to_string(), "test");
assert_eq!(format!("{}", test), "test");
let mut vec = Vec::new();
test.dyn_write_into(&mut vec).unwrap();
assert_eq!(vec, vec![b't', b'e', b's', b't']);
}
}
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