comm-central/third_party/rust/askama_derive/src/lib.rs

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#![cfg_attr(docsrs, feature(doc_cfg, doc_auto_cfg))]
#![deny(elided_lifetimes_in_paths)]
#![deny(unreachable_pub)]
mod config;
mod generator;
mod heritage;
mod html;
mod input;
mod integration;
#[cfg(test)]
mod tests;
use std::borrow::{Borrow, Cow};
use std::collections::hash_map::{Entry, HashMap};
use std::fmt;
use std::hash::{BuildHasher, Hash};
use std::path::Path;
use std::sync::Mutex;
use parser::{Parsed, ascii_str, strip_common};
#[cfg(not(feature = "__standalone"))]
use proc_macro::TokenStream as TokenStream12;
#[cfg(feature = "__standalone")]
use proc_macro2::TokenStream as TokenStream12;
use proc_macro2::{Delimiter, Group, Span, TokenStream, TokenTree};
use quote::{quote, quote_spanned};
use rustc_hash::FxBuildHasher;
use crate::config::{Config, read_config_file};
use crate::generator::{TmplKind, template_to_string};
use crate::heritage::{Context, Heritage};
use crate::input::{AnyTemplateArgs, Print, TemplateArgs, TemplateInput};
use crate::integration::{Buffer, build_template_enum};
/// The `Template` derive macro and its `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.
///
/// ## Attributes
///
/// The following sub-attributes are currently recognized:
///
/// ### path
///
/// E.g. `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
///
/// E.g. `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` (e.g. `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`.
///
/// ### `in_doc`
///
/// E.g. `in_doc = true`
///
/// As an alternative to supplying the code template code in an external file (as `path` argument),
/// or as a string (as `source` argument), you can also enable the `"code-in-doc"` feature.
/// With this feature, you can specify the template code directly in the documentation
/// of the template `struct`.
///
/// Instead of `path = "…"` or `source = "…"`, specify `in_doc = true` in the `#[template]`
/// attribute, and in the struct's documentation add a `askama` code block:
///
/// ```rust,ignore
/// /// ```askama
/// /// <div>{{ lines|linebreaksbr }}</div>
/// /// ```
/// #[derive(Template)]
/// #[template(ext = "html", in_doc = true)]
/// struct Example<'a> {
/// lines: &'a str,
/// }
/// ```
///
/// ### print
///
/// E.g. `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.
///
/// ### block
///
/// E.g. `block = "block_name"`
///
/// Renders the block by itself.
/// Expressions outside of the block are not required by the struct, and
/// inheritance is also supported. This can be useful when you need to
/// decompose your template for partial rendering, without needing to
/// extract the partial into a separate template or macro.
///
/// ```rust,ignore
/// #[derive(Template)]
/// #[template(path = "hello.html", block = "hello")]
/// struct HelloTemplate<'a> { ... }
/// ```
///
/// ### blocks
///
/// E.g. `blocks = ["title", "content"]`
///
/// Automatically generates (a number of) sub-templates that act as if they had a
/// `block = "..."` attribute. You can access the sub-templates with the method
/// <code>my_template.as_<em>block_name</em>()</code>, where *`block_name`* is the
/// name of the block:
///
/// ```rust,ignore
/// #[derive(Template)]
/// #[template(
/// ext = "txt",
/// source = "
/// {% block title %} ... {% endblock %}
/// {% block content %} ... {% endblock %}
/// ",
/// blocks = ["title", "content"]
/// )]
/// struct News<'a> {
/// title: &'a str,
/// message: &'a str,
/// }
///
/// let news = News {
/// title: "Announcing Rust 1.84.1",
/// message: "The Rust team has published a new point release of Rust, 1.84.1.",
/// };
/// assert_eq!(
/// news.as_title().render().unwrap(),
/// "<h1>Announcing Rust 1.84.1</h1>"
/// );
/// ```
///
/// ### escape
///
/// E.g. `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
///
/// E.g. `syntax = "foo"`
///
/// Set the syntax name for a parser defined in the configuration file.
/// The default syntax, `"default"`, is the one provided by Askama.
///
/// ### askama
///
/// E.g. `askama = askama`
///
/// If you are using askama in a subproject, a library or a [macro][book-macro], it might be
/// necessary to specify the [path][book-tree] where to find the module `askama`:
///
///
/// ```rust,ignore
/// #[doc(hidden)]
/// use askama as __askama;
///
/// #[macro_export]
/// macro_rules! new_greeter {
/// ($name:ident) => {
/// #[derive(Debug, $crate::askama::Template)]
/// #[template(
/// ext = "txt",
/// source = "Hello, world!",
/// askama = $crate::__askama
/// )]
/// struct $name;
/// }
/// }
///
/// new_greeter!(HelloWorld);
/// assert_eq!(HelloWorld.to_string(), Ok("Hello, world."));
/// ```
#[allow(clippy::useless_conversion)] // To be compatible with both `TokenStream`s
#[cfg_attr(
not(feature = "__standalone"),
proc_macro_derive(Template, attributes(template))
)]
#[must_use]
pub fn derive_template(input: TokenStream12) -> TokenStream12 {
let ast = match syn::parse2(input.into()) {
Ok(ast) => ast,
Err(err) => {
let msgs = err.into_iter().map(|err| err.to_string());
let ts = quote! {
const _: () = {
extern crate core;
#(core::compile_error!(#msgs);)*
};
};
return ts.into();
}
};
let mut buf = Buffer::new();
let mut args = AnyTemplateArgs::new(&ast);
let crate_name = args
.as_mut()
.map(|a| a.take_crate_name())
.unwrap_or_default();
let result = args.and_then(|args| build_template(&mut buf, &ast, args));
let ts = if let Err(CompileError { msg, span }) = result {
let mut ts = quote_spanned! {
span.unwrap_or(ast.ident.span()) =>
askama::helpers::core::compile_error!(#msg);
};
buf.clear();
if build_skeleton(&mut buf, &ast).is_ok() {
let source: TokenStream = buf.into_string().parse().unwrap();
ts.extend(source);
}
ts
} else {
buf.into_string().parse().unwrap()
};
let ts = TokenTree::Group(Group::new(Delimiter::None, ts));
let ts = if let Some(crate_name) = crate_name {
quote! {
const _: () = {
use #crate_name as askama;
#ts
};
}
} else {
quote! {
const _: () = {
extern crate askama;
#ts
};
}
};
ts.into()
}
fn build_skeleton(buf: &mut Buffer, ast: &syn::DeriveInput) -> Result<usize, CompileError> {
let template_args = TemplateArgs::fallback();
let config = Config::new("", None, None, None, None)?;
let input = TemplateInput::new(ast, None, config, &template_args)?;
let mut contexts = HashMap::default();
let parsed = parser::Parsed::default();
contexts.insert(&input.path, Context::empty(&parsed));
template_to_string(buf, &input, &contexts, None, TmplKind::Struct)
}
/// Takes a `syn::DeriveInput` and generates source code for it
///
/// Reads the metadata from the `template()` attribute to get the template
/// metadata, then fetches the source from the filesystem. The source is
/// parsed, and the parse tree is fed to the code generator. Will print
/// the parse tree and/or generated source according to the `print` key's
/// value as passed to the `template()` attribute.
pub(crate) fn build_template(
buf: &mut Buffer,
ast: &syn::DeriveInput,
args: AnyTemplateArgs,
) -> Result<usize, CompileError> {
let err_span;
let mut result = match args {
AnyTemplateArgs::Struct(item) => {
err_span = item.source.1.or(item.template_span);
build_template_item(buf, ast, None, &item, TmplKind::Struct)
}
AnyTemplateArgs::Enum {
enum_args,
vars_args,
has_default_impl,
} => {
err_span = enum_args
.as_ref()
.and_then(|v| v.source.as_ref())
.map(|s| s.span())
.or_else(|| enum_args.as_ref().map(|v| v.template.span()));
build_template_enum(buf, ast, enum_args, vars_args, has_default_impl)
}
};
if let Err(err) = &mut result {
if err.span.is_none() {
err.span = err_span;
}
}
result
}
fn build_template_item(
buf: &mut Buffer,
ast: &syn::DeriveInput,
enum_ast: Option<&syn::DeriveInput>,
template_args: &TemplateArgs,
tmpl_kind: TmplKind<'_>,
) -> Result<usize, CompileError> {
let config_path = template_args.config_path();
let (s, full_config_path) = read_config_file(config_path, template_args.config_span)?;
let config = Config::new(
&s,
config_path,
template_args.whitespace,
template_args.config_span,
full_config_path,
)?;
let input = TemplateInput::new(ast, enum_ast, config, template_args)?;
let mut templates = HashMap::default();
input.find_used_templates(&mut templates)?;
let mut contexts = HashMap::default();
for (path, parsed) in &templates {
contexts.insert(path, Context::new(input.config, path, parsed)?);
}
let ctx = &contexts[&input.path];
let heritage = if !ctx.blocks.is_empty() || ctx.extends.is_some() {
Some(Heritage::new(ctx, &contexts))
} else {
None
};
if let Some((block_name, block_span)) = input.block {
let has_block = match &heritage {
Some(heritage) => heritage.blocks.contains_key(block_name),
None => ctx.blocks.contains_key(block_name),
};
if !has_block {
return Err(CompileError::no_file_info(
format_args!("cannot find block `{block_name}`"),
Some(block_span),
));
}
}
if input.print == Print::Ast || input.print == Print::All {
eprintln!("{:?}", templates[&input.path].nodes());
}
let mark = buf.get_mark();
let size_hint = template_to_string(buf, &input, &contexts, heritage.as_ref(), tmpl_kind)?;
if input.print == Print::Code || input.print == Print::All {
eprintln!("{}", buf.marked_text(mark));
}
Ok(size_hint)
}
#[derive(Debug, Clone)]
struct CompileError {
msg: String,
span: Option<Span>,
}
impl CompileError {
fn new<S: fmt::Display>(msg: S, file_info: Option<FileInfo<'_>>) -> Self {
Self::new_with_span(msg, file_info, None)
}
fn new_with_span<S: fmt::Display>(
msg: S,
file_info: Option<FileInfo<'_>>,
span: Option<Span>,
) -> Self {
let msg = match file_info {
Some(file_info) => format!("{msg}{file_info}"),
None => msg.to_string(),
};
Self { msg, span }
}
fn no_file_info<S: ToString>(msg: S, span: Option<Span>) -> Self {
Self {
msg: msg.to_string(),
span,
}
}
}
impl std::error::Error for CompileError {}
impl fmt::Display for CompileError {
#[inline]
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt.write_str(&self.msg)
}
}
#[derive(Debug, Clone, Copy)]
struct FileInfo<'a> {
path: &'a Path,
source: Option<&'a str>,
node_source: Option<&'a str>,
}
impl<'a> FileInfo<'a> {
fn new(path: &'a Path, source: Option<&'a str>, node_source: Option<&'a str>) -> Self {
Self {
path,
source,
node_source,
}
}
fn of(node: parser::Span<'a>, path: &'a Path, parsed: &'a Parsed) -> Self {
let source = parsed.source();
Self {
path,
source: Some(source),
node_source: node.as_suffix_of(source),
}
}
}
impl fmt::Display for FileInfo<'_> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
if let (Some(source), Some(node_source)) = (self.source, self.node_source) {
let (error_info, file_path) = generate_error_info(source, node_source, self.path);
write!(
f,
"\n --> {file_path}:{row}:{column}\n{source_after}",
row = error_info.row,
column = error_info.column,
source_after = error_info.source_after,
)
} else {
write!(
f,
"\n --> {}",
match std::env::current_dir() {
Ok(cwd) => fmt_left!(move "{}", strip_common(&cwd, self.path)),
Err(_) => fmt_right!("{}", self.path.display()),
}
)
}
}
}
struct ErrorInfo {
row: usize,
column: usize,
source_after: String,
}
fn generate_row_and_column(src: &str, input: &str) -> ErrorInfo {
const MAX_LINE_LEN: usize = 80;
let offset = src.len() - input.len();
let (source_before, source_after) = src.split_at(offset);
let source_after = match source_after
.char_indices()
.enumerate()
.take(MAX_LINE_LEN + 1)
.last()
{
Some((MAX_LINE_LEN, (i, _))) => format!("{:?}...", &source_after[..i]),
_ => format!("{source_after:?}"),
};
let (row, last_line) = source_before.lines().enumerate().last().unwrap_or_default();
let column = last_line.chars().count();
ErrorInfo {
row: row + 1,
column,
source_after,
}
}
/// Return the error related information and its display file path.
fn generate_error_info(src: &str, input: &str, file_path: &Path) -> (ErrorInfo, String) {
let file_path = match std::env::current_dir() {
Ok(cwd) => strip_common(&cwd, file_path),
Err(_) => file_path.display().to_string(),
};
let error_info = generate_row_and_column(src, input);
(error_info, file_path)
}
struct MsgValidEscapers<'a>(&'a [(Vec<Cow<'a, str>>, Cow<'a, str>)]);
impl fmt::Display for MsgValidEscapers<'_> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let mut exts = self
.0
.iter()
.flat_map(|(exts, _)| exts)
.map(|x| format!("{x:?}"))
.collect::<Vec<_>>();
exts.sort();
write!(f, "The available extensions are: {}", exts.join(", "))
}
}
#[derive(Debug)]
struct OnceMap<K, V>([Mutex<HashMap<K, V, FxBuildHasher>>; 8]);
impl<K, V> Default for OnceMap<K, V> {
fn default() -> Self {
Self(Default::default())
}
}
impl<K: Hash + Eq, V> OnceMap<K, V> {
// The API of this function was copied, and adapted from the `once_map` crate
fn get_or_try_insert<T, Q, E>(
&self,
key: &Q,
make_key_value: impl FnOnce(&Q) -> Result<(K, V), E>,
to_value: impl FnOnce(&V) -> T,
) -> Result<T, E>
where
K: Borrow<Q>,
Q: Hash + Eq,
{
let shard_idx = (FxBuildHasher.hash_one(key) % self.0.len() as u64) as usize;
let mut shard = self.0[shard_idx].lock().unwrap();
Ok(to_value(if let Some(v) = shard.get(key) {
v
} else {
let (k, v) = make_key_value(key)?;
match shard.entry(k) {
Entry::Vacant(entry) => entry.insert(v),
Entry::Occupied(_) => unreachable!("key in map when it should not have been"),
}
}))
}
}
enum EitherFormat<L, R>
where
L: for<'a, 'b> Fn(&'a mut fmt::Formatter<'b>) -> fmt::Result,
R: for<'a, 'b> Fn(&'a mut fmt::Formatter<'b>) -> fmt::Result,
{
Left(L),
Right(R),
}
impl<L, R> fmt::Display for EitherFormat<L, R>
where
L: for<'a, 'b> Fn(&'a mut fmt::Formatter<'b>) -> fmt::Result,
R: for<'a, 'b> Fn(&'a mut fmt::Formatter<'b>) -> fmt::Result,
{
#[inline]
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Self::Left(v) => v(f),
Self::Right(v) => v(f),
}
}
}
macro_rules! fmt_left {
(move $fmt:literal $($tt:tt)*) => {
$crate::EitherFormat::Left(move |f: &mut std::fmt::Formatter<'_>| {
write!(f, $fmt $($tt)*)
})
};
($fmt:literal $($tt:tt)*) => {
$crate::EitherFormat::Left(|f: &mut std::fmt::Formatter<'_>| {
write!(f, $fmt $($tt)*)
})
};
}
macro_rules! fmt_right {
(move $fmt:literal $($tt:tt)*) => {
$crate::EitherFormat::Right(move |f: &mut std::fmt::Formatter<'_>| {
write!(f, $fmt $($tt)*)
})
};
($fmt:literal $($tt:tt)*) => {
$crate::EitherFormat::Right(|f: &mut std::fmt::Formatter<'_>| {
write!(f, $fmt $($tt)*)
})
};
}
pub(crate) use {fmt_left, fmt_right};
// This is used by the code generator to decide whether a named filter is part of
// Askama or should refer to a local `filters` module.
const BUILTIN_FILTERS: &[&str] = &[
"capitalize",
"center",
"indent",
"lower",
"lowercase",
"title",
"trim",
"truncate",
"upper",
"uppercase",
"wordcount",
];
// Built-in filters that need the `alloc` feature.
const BUILTIN_FILTERS_NEED_ALLOC: &[&str] = &["center", "truncate"];