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-rw-r--r--askama_derive/src/generator.rs2141
1 files changed, 2141 insertions, 0 deletions
diff --git a/askama_derive/src/generator.rs b/askama_derive/src/generator.rs
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+++ b/askama_derive/src/generator.rs
@@ -0,0 +1,2141 @@
+use crate::config::{get_template_source, read_config_file, Config, WhitespaceHandling};
+use crate::heritage::{Context, Heritage};
+use crate::input::{Print, Source, TemplateInput};
+use crate::parser::{parse, Cond, CondTest, Expr, Loop, Node, Target, When, Whitespace, Ws};
+use crate::CompileError;
+
+use proc_macro::TokenStream;
+use quote::{quote, ToTokens};
+
+use std::collections::HashMap;
+use std::path::{Path, PathBuf};
+use std::{cmp, hash, mem, str};
+
+/// The actual implementation for askama_derive::Template
+pub(crate) fn derive_template(input: TokenStream) -> TokenStream {
+ let ast: syn::DeriveInput = syn::parse(input).unwrap();
+ match build_template(&ast) {
+ Ok(source) => source.parse().unwrap(),
+ Err(e) => e.into_compile_error(),
+ }
+}
+
+/// 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.
+fn build_template(ast: &syn::DeriveInput) -> Result<String, CompileError> {
+ let template_args = TemplateArgs::new(ast)?;
+ let config_toml = read_config_file(&template_args.config_path)?;
+ let config = Config::new(&config_toml)?;
+ let input = TemplateInput::new(ast, &config, template_args)?;
+ let source: String = match input.source {
+ Source::Source(ref s) => s.clone(),
+ Source::Path(_) => get_template_source(&input.path)?,
+ };
+
+ let mut sources = HashMap::new();
+ find_used_templates(&input, &mut sources, source)?;
+
+ let mut parsed = HashMap::new();
+ for (path, src) in &sources {
+ parsed.insert(path.as_path(), parse(src, input.syntax)?);
+ }
+
+ let mut contexts = HashMap::new();
+ for (path, nodes) in &parsed {
+ contexts.insert(*path, Context::new(input.config, path, nodes)?);
+ }
+
+ let ctx = &contexts[input.path.as_path()];
+ let heritage = if !ctx.blocks.is_empty() || ctx.extends.is_some() {
+ Some(Heritage::new(ctx, &contexts))
+ } else {
+ None
+ };
+
+ if input.print == Print::Ast || input.print == Print::All {
+ eprintln!("{:?}", parsed[input.path.as_path()]);
+ }
+
+ let code = Generator::new(
+ &input,
+ &contexts,
+ heritage.as_ref(),
+ MapChain::new(),
+ config.whitespace,
+ )
+ .build(&contexts[input.path.as_path()])?;
+ if input.print == Print::Code || input.print == Print::All {
+ eprintln!("{}", code);
+ }
+ Ok(code)
+}
+
+#[derive(Default)]
+pub(crate) struct TemplateArgs {
+ pub(crate) source: Option<Source>,
+ pub(crate) print: Print,
+ pub(crate) escaping: Option<String>,
+ pub(crate) ext: Option<String>,
+ pub(crate) syntax: Option<String>,
+ pub(crate) config_path: Option<String>,
+}
+
+impl TemplateArgs {
+ fn new(ast: &'_ syn::DeriveInput) -> Result<Self, CompileError> {
+ // Check that an attribute called `template()` exists once and that it is
+ // the proper type (list).
+ let mut template_args = None;
+ for attr in &ast.attrs {
+ let ident = match attr.path.get_ident() {
+ Some(ident) => ident,
+ None => continue,
+ };
+
+ if ident == "template" {
+ if template_args.is_some() {
+ return Err("duplicated 'template' attribute".into());
+ }
+
+ match attr.parse_meta() {
+ Ok(syn::Meta::List(syn::MetaList { nested, .. })) => {
+ template_args = Some(nested);
+ }
+ Ok(_) => return Err("'template' attribute must be a list".into()),
+ Err(e) => return Err(format!("unable to parse attribute: {}", e).into()),
+ }
+ }
+ }
+ let template_args =
+ template_args.ok_or_else(|| CompileError::from("no attribute 'template' found"))?;
+
+ let mut args = Self::default();
+ // Loop over the meta attributes and find everything that we
+ // understand. Return a CompileError if something is not right.
+ // `source` contains an enum that can represent `path` or `source`.
+ for item in template_args {
+ let pair = match item {
+ syn::NestedMeta::Meta(syn::Meta::NameValue(ref pair)) => pair,
+ _ => {
+ return Err(format!(
+ "unsupported attribute argument {:?}",
+ item.to_token_stream()
+ )
+ .into())
+ }
+ };
+ let ident = match pair.path.get_ident() {
+ Some(ident) => ident,
+ None => unreachable!("not possible in syn::Meta::NameValue(…)"),
+ };
+
+ if ident == "path" {
+ if let syn::Lit::Str(ref s) = pair.lit {
+ if args.source.is_some() {
+ return Err("must specify 'source' or 'path', not both".into());
+ }
+ args.source = Some(Source::Path(s.value()));
+ } else {
+ return Err("template path must be string literal".into());
+ }
+ } else if ident == "source" {
+ if let syn::Lit::Str(ref s) = pair.lit {
+ if args.source.is_some() {
+ return Err("must specify 'source' or 'path', not both".into());
+ }
+ args.source = Some(Source::Source(s.value()));
+ } else {
+ return Err("template source must be string literal".into());
+ }
+ } else if ident == "print" {
+ if let syn::Lit::Str(ref s) = pair.lit {
+ args.print = s.value().parse()?;
+ } else {
+ return Err("print value must be string literal".into());
+ }
+ } else if ident == "escape" {
+ if let syn::Lit::Str(ref s) = pair.lit {
+ args.escaping = Some(s.value());
+ } else {
+ return Err("escape value must be string literal".into());
+ }
+ } else if ident == "ext" {
+ if let syn::Lit::Str(ref s) = pair.lit {
+ args.ext = Some(s.value());
+ } else {
+ return Err("ext value must be string literal".into());
+ }
+ } else if ident == "syntax" {
+ if let syn::Lit::Str(ref s) = pair.lit {
+ args.syntax = Some(s.value())
+ } else {
+ return Err("syntax value must be string literal".into());
+ }
+ } else if ident == "config" {
+ if let syn::Lit::Str(ref s) = pair.lit {
+ args.config_path = Some(s.value())
+ } else {
+ return Err("config value must be string literal".into());
+ }
+ } else {
+ return Err(format!("unsupported attribute key {:?} found", ident).into());
+ }
+ }
+
+ Ok(args)
+ }
+}
+
+fn find_used_templates(
+ input: &TemplateInput<'_>,
+ map: &mut HashMap<PathBuf, String>,
+ source: String,
+) -> Result<(), CompileError> {
+ let mut dependency_graph = Vec::new();
+ let mut check = vec![(input.path.clone(), source)];
+ while let Some((path, source)) = check.pop() {
+ for n in parse(&source, input.syntax)? {
+ match n {
+ Node::Extends(Expr::StrLit(extends)) => {
+ let extends = input.config.find_template(extends, Some(&path))?;
+ let dependency_path = (path.clone(), extends.clone());
+ if dependency_graph.contains(&dependency_path) {
+ return Err(format!(
+ "cyclic dependecy in graph {:#?}",
+ dependency_graph
+ .iter()
+ .map(|e| format!("{:#?} --> {:#?}", e.0, e.1))
+ .collect::<Vec<String>>()
+ )
+ .into());
+ }
+ dependency_graph.push(dependency_path);
+ let source = get_template_source(&extends)?;
+ check.push((extends, source));
+ }
+ Node::Import(_, import, _) => {
+ let import = input.config.find_template(import, Some(&path))?;
+ let source = get_template_source(&import)?;
+ check.push((import, source));
+ }
+ _ => {}
+ }
+ }
+ map.insert(path, source);
+ }
+ Ok(())
+}
+struct Generator<'a, S: std::hash::BuildHasher> {
+ // The template input state: original struct AST and attributes
+ input: &'a TemplateInput<'a>,
+ // All contexts, keyed by the package-relative template path
+ contexts: &'a HashMap<&'a Path, Context<'a>, S>,
+ // The heritage contains references to blocks and their ancestry
+ heritage: Option<&'a Heritage<'a>>,
+ // Variables accessible directly from the current scope (not redirected to context)
+ locals: MapChain<'a, &'a str, LocalMeta>,
+ // Suffix whitespace from the previous literal. Will be flushed to the
+ // output buffer unless suppressed by whitespace suppression on the next
+ // non-literal.
+ next_ws: Option<&'a str>,
+ // Whitespace suppression from the previous non-literal. Will be used to
+ // determine whether to flush prefix whitespace from the next literal.
+ skip_ws: WhitespaceHandling,
+ // If currently in a block, this will contain the name of a potential parent block
+ super_block: Option<(&'a str, usize)>,
+ // buffer for writable
+ buf_writable: Vec<Writable<'a>>,
+ // Counter for write! hash named arguments
+ named: usize,
+ // If set to `suppress`, the whitespace characters will be removed by default unless `+` is
+ // used.
+ whitespace: WhitespaceHandling,
+}
+
+impl<'a, S: std::hash::BuildHasher> Generator<'a, S> {
+ fn new<'n>(
+ input: &'n TemplateInput<'_>,
+ contexts: &'n HashMap<&'n Path, Context<'n>, S>,
+ heritage: Option<&'n Heritage<'_>>,
+ locals: MapChain<'n, &'n str, LocalMeta>,
+ whitespace: WhitespaceHandling,
+ ) -> Generator<'n, S> {
+ Generator {
+ input,
+ contexts,
+ heritage,
+ locals,
+ next_ws: None,
+ skip_ws: WhitespaceHandling::Preserve,
+ super_block: None,
+ buf_writable: vec![],
+ named: 0,
+ whitespace,
+ }
+ }
+
+ fn child(&mut self) -> Generator<'_, S> {
+ let locals = MapChain::with_parent(&self.locals);
+ Self::new(
+ self.input,
+ self.contexts,
+ self.heritage,
+ locals,
+ self.whitespace,
+ )
+ }
+
+ // Takes a Context and generates the relevant implementations.
+ fn build(mut self, ctx: &'a Context<'_>) -> Result<String, CompileError> {
+ let mut buf = Buffer::new(0);
+ if !ctx.blocks.is_empty() {
+ if let Some(parent) = self.input.parent {
+ self.deref_to_parent(&mut buf, parent)?;
+ }
+ };
+
+ self.impl_template(ctx, &mut buf)?;
+ self.impl_display(&mut buf)?;
+
+ #[cfg(feature = "with-actix-web")]
+ self.impl_actix_web_responder(&mut buf)?;
+ #[cfg(feature = "with-axum")]
+ self.impl_axum_into_response(&mut buf)?;
+ #[cfg(feature = "with-gotham")]
+ self.impl_gotham_into_response(&mut buf)?;
+ #[cfg(feature = "with-mendes")]
+ self.impl_mendes_responder(&mut buf)?;
+ #[cfg(feature = "with-rocket")]
+ self.impl_rocket_responder(&mut buf)?;
+ #[cfg(feature = "with-tide")]
+ self.impl_tide_integrations(&mut buf)?;
+ #[cfg(feature = "with-warp")]
+ self.impl_warp_reply(&mut buf)?;
+
+ Ok(buf.buf)
+ }
+
+ // Implement `Template` for the given context struct.
+ fn impl_template(
+ &mut self,
+ ctx: &'a Context<'_>,
+ buf: &mut Buffer,
+ ) -> Result<(), CompileError> {
+ self.write_header(buf, "::askama::Template", None)?;
+ buf.writeln(
+ "fn render_into(&self, writer: &mut (impl ::std::fmt::Write + ?Sized)) -> \
+ ::askama::Result<()> {",
+ )?;
+
+ // Make sure the compiler understands that the generated code depends on the template files.
+ for path in self.contexts.keys() {
+ // Skip the fake path of templates defined in rust source.
+ let path_is_valid = match self.input.source {
+ Source::Path(_) => true,
+ Source::Source(_) => path != &self.input.path,
+ };
+ if path_is_valid {
+ let path = path.to_str().unwrap();
+ buf.writeln(
+ &quote! {
+ include_bytes!(#path);
+ }
+ .to_string(),
+ )?;
+ }
+ }
+
+ let size_hint = if let Some(heritage) = self.heritage {
+ self.handle(heritage.root, heritage.root.nodes, buf, AstLevel::Top)
+ } else {
+ self.handle(ctx, ctx.nodes, buf, AstLevel::Top)
+ }?;
+
+ self.flush_ws(Ws(None, None));
+ buf.writeln("::askama::Result::Ok(())")?;
+ buf.writeln("}")?;
+
+ buf.writeln("const EXTENSION: ::std::option::Option<&'static ::std::primitive::str> = ")?;
+ buf.writeln(&format!("{:?}", self.input.extension()))?;
+ buf.writeln(";")?;
+
+ buf.writeln("const SIZE_HINT: ::std::primitive::usize = ")?;
+ buf.writeln(&format!("{}", size_hint))?;
+ buf.writeln(";")?;
+
+ buf.writeln("const MIME_TYPE: &'static ::std::primitive::str = ")?;
+ buf.writeln(&format!("{:?}", &self.input.mime_type))?;
+ buf.writeln(";")?;
+
+ buf.writeln("}")?;
+ Ok(())
+ }
+
+ // Implement `Deref<Parent>` for an inheriting context struct.
+ fn deref_to_parent(
+ &mut self,
+ buf: &mut Buffer,
+ parent_type: &syn::Type,
+ ) -> Result<(), CompileError> {
+ self.write_header(buf, "::std::ops::Deref", None)?;
+ buf.writeln(&format!(
+ "type Target = {};",
+ parent_type.into_token_stream()
+ ))?;
+ buf.writeln("#[inline]")?;
+ buf.writeln("fn deref(&self) -> &Self::Target {")?;
+ buf.writeln("&self._parent")?;
+ buf.writeln("}")?;
+ buf.writeln("}")
+ }
+
+ // Implement `Display` for the given context struct.
+ fn impl_display(&mut self, buf: &mut Buffer) -> Result<(), CompileError> {
+ self.write_header(buf, "::std::fmt::Display", None)?;
+ buf.writeln("#[inline]")?;
+ buf.writeln("fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {")?;
+ buf.writeln("::askama::Template::render_into(self, f).map_err(|_| ::std::fmt::Error {})")?;
+ buf.writeln("}")?;
+ buf.writeln("}")
+ }
+
+ // Implement Actix-web's `Responder`.
+ #[cfg(feature = "with-actix-web")]
+ fn impl_actix_web_responder(&mut self, buf: &mut Buffer) -> Result<(), CompileError> {
+ self.write_header(buf, "::askama_actix::actix_web::Responder", None)?;
+ buf.writeln("type Body = ::askama_actix::actix_web::body::BoxBody;")?;
+ buf.writeln("#[inline]")?;
+ buf.writeln(
+ "fn respond_to(self, _req: &::askama_actix::actix_web::HttpRequest) \
+ -> ::askama_actix::actix_web::HttpResponse<Self::Body> {",
+ )?;
+ buf.writeln("<Self as ::askama_actix::TemplateToResponse>::to_response(&self)")?;
+ buf.writeln("}")?;
+ buf.writeln("}")
+ }
+
+ // Implement Axum's `IntoResponse`.
+ #[cfg(feature = "with-axum")]
+ fn impl_axum_into_response(&mut self, buf: &mut Buffer) -> Result<(), CompileError> {
+ self.write_header(buf, "::askama_axum::IntoResponse", None)?;
+ buf.writeln("#[inline]")?;
+ buf.writeln(
+ "fn into_response(self)\
+ -> ::askama_axum::Response {",
+ )?;
+ let ext = self.input.extension().unwrap_or("txt");
+ buf.writeln(&format!("::askama_axum::into_response(&self, {:?})", ext))?;
+ buf.writeln("}")?;
+ buf.writeln("}")
+ }
+
+ // Implement gotham's `IntoResponse`.
+ #[cfg(feature = "with-gotham")]
+ fn impl_gotham_into_response(&mut self, buf: &mut Buffer) -> Result<(), CompileError> {
+ self.write_header(buf, "::askama_gotham::IntoResponse", None)?;
+ buf.writeln("#[inline]")?;
+ buf.writeln(
+ "fn into_response(self, _state: &::askama_gotham::State)\
+ -> ::askama_gotham::Response<::askama_gotham::Body> {",
+ )?;
+ let ext = self.input.extension().unwrap_or("txt");
+ buf.writeln(&format!("::askama_gotham::respond(&self, {:?})", ext))?;
+ buf.writeln("}")?;
+ buf.writeln("}")
+ }
+
+ // Implement mendes' `Responder`.
+ #[cfg(feature = "with-mendes")]
+ fn impl_mendes_responder(&mut self, buf: &mut Buffer) -> Result<(), CompileError> {
+ let param = syn::parse_str("A: ::mendes::Application").unwrap();
+
+ let mut generics = self.input.ast.generics.clone();
+ generics.params.push(param);
+ let (_, orig_ty_generics, _) = self.input.ast.generics.split_for_impl();
+ let (impl_generics, _, where_clause) = generics.split_for_impl();
+
+ let mut where_clause = match where_clause {
+ Some(clause) => clause.clone(),
+ None => syn::WhereClause {
+ where_token: syn::Token![where](proc_macro2::Span::call_site()),
+ predicates: syn::punctuated::Punctuated::new(),
+ },
+ };
+
+ where_clause
+ .predicates
+ .push(syn::parse_str("A::ResponseBody: From<String>").unwrap());
+ where_clause
+ .predicates
+ .push(syn::parse_str("A::Error: From<::askama_mendes::Error>").unwrap());
+
+ buf.writeln(
+ format!(
+ "{} {} for {} {} {{",
+ quote!(impl#impl_generics),
+ "::mendes::application::IntoResponse<A>",
+ self.input.ast.ident,
+ quote!(#orig_ty_generics #where_clause),
+ )
+ .as_ref(),
+ )?;
+
+ buf.writeln(
+ "fn into_response(self, app: &A, req: &::mendes::http::request::Parts) \
+ -> ::mendes::http::Response<A::ResponseBody> {",
+ )?;
+
+ buf.writeln(&format!(
+ "::askama_mendes::into_response(app, req, &self, {:?})",
+ self.input.extension()
+ ))?;
+ buf.writeln("}")?;
+ buf.writeln("}")?;
+ Ok(())
+ }
+
+ // Implement Rocket's `Responder`.
+ #[cfg(feature = "with-rocket")]
+ fn impl_rocket_responder(&mut self, buf: &mut Buffer) -> Result<(), CompileError> {
+ let lifetime = syn::Lifetime::new("'askama", proc_macro2::Span::call_site());
+ let param = syn::GenericParam::Lifetime(syn::LifetimeDef::new(lifetime));
+ self.write_header(
+ buf,
+ "::askama_rocket::Responder<'askama>",
+ Some(vec![param]),
+ )?;
+
+ buf.writeln("#[inline]")?;
+ buf.writeln(
+ "fn respond_to(self, _: &::askama_rocket::Request) \
+ -> ::askama_rocket::Result<'askama> {",
+ )?;
+ let ext = self.input.extension().unwrap_or("txt");
+ buf.writeln(&format!("::askama_rocket::respond(&self, {:?})", ext))?;
+
+ buf.writeln("}")?;
+ buf.writeln("}")?;
+ Ok(())
+ }
+
+ #[cfg(feature = "with-tide")]
+ fn impl_tide_integrations(&mut self, buf: &mut Buffer) -> Result<(), CompileError> {
+ let ext = self.input.extension().unwrap_or("txt");
+
+ self.write_header(
+ buf,
+ "::std::convert::TryInto<::askama_tide::tide::Body>",
+ None,
+ )?;
+ buf.writeln(
+ "type Error = ::askama_tide::askama::Error;\n\
+ #[inline]\n\
+ fn try_into(self) -> ::askama_tide::askama::Result<::askama_tide::tide::Body> {",
+ )?;
+ buf.writeln(&format!("::askama_tide::try_into_body(&self, {:?})", &ext))?;
+ buf.writeln("}")?;
+ buf.writeln("}")?;
+
+ buf.writeln("#[allow(clippy::from_over_into)]")?;
+ self.write_header(buf, "Into<::askama_tide::tide::Response>", None)?;
+ buf.writeln("#[inline]")?;
+ buf.writeln("fn into(self) -> ::askama_tide::tide::Response {")?;
+ buf.writeln(&format!("::askama_tide::into_response(&self, {:?})", ext))?;
+ buf.writeln("}\n}")
+ }
+
+ #[cfg(feature = "with-warp")]
+ fn impl_warp_reply(&mut self, buf: &mut Buffer) -> Result<(), CompileError> {
+ self.write_header(buf, "::askama_warp::warp::reply::Reply", None)?;
+ buf.writeln("#[inline]")?;
+ buf.writeln("fn into_response(self) -> ::askama_warp::warp::reply::Response {")?;
+ let ext = self.input.extension().unwrap_or("txt");
+ buf.writeln(&format!("::askama_warp::reply(&self, {:?})", ext))?;
+ buf.writeln("}")?;
+ buf.writeln("}")
+ }
+
+ // Writes header for the `impl` for `TraitFromPathName` or `Template`
+ // for the given context struct.
+ fn write_header(
+ &mut self,
+ buf: &mut Buffer,
+ target: &str,
+ params: Option<Vec<syn::GenericParam>>,
+ ) -> Result<(), CompileError> {
+ let mut generics = self.input.ast.generics.clone();
+ if let Some(params) = params {
+ for param in params {
+ generics.params.push(param);
+ }
+ }
+ let (_, orig_ty_generics, _) = self.input.ast.generics.split_for_impl();
+ let (impl_generics, _, where_clause) = generics.split_for_impl();
+ buf.writeln(
+ format!(
+ "{} {} for {}{} {{",
+ quote!(impl#impl_generics),
+ target,
+ self.input.ast.ident,
+ quote!(#orig_ty_generics #where_clause),
+ )
+ .as_ref(),
+ )
+ }
+
+ /* Helper methods for handling node types */
+
+ fn handle(
+ &mut self,
+ ctx: &'a Context<'_>,
+ nodes: &'a [Node<'_>],
+ buf: &mut Buffer,
+ level: AstLevel,
+ ) -> Result<usize, CompileError> {
+ let mut size_hint = 0;
+ for n in nodes {
+ match *n {
+ Node::Lit(lws, val, rws) => {
+ self.visit_lit(lws, val, rws);
+ }
+ Node::Comment(ws) => {
+ self.write_comment(ws);
+ }
+ Node::Expr(ws, ref val) => {
+ self.write_expr(ws, val);
+ }
+ Node::LetDecl(ws, ref var) => {
+ self.write_let_decl(buf, ws, var)?;
+ }
+ Node::Let(ws, ref var, ref val) => {
+ self.write_let(buf, ws, var, val)?;
+ }
+ Node::Cond(ref conds, ws) => {
+ self.write_cond(ctx, buf, conds, ws)?;
+ }
+ Node::Match(ws1, ref expr, ref arms, ws2) => {
+ self.write_match(ctx, buf, ws1, expr, arms, ws2)?;
+ }
+ Node::Loop(ref loop_block) => {
+ self.write_loop(ctx, buf, loop_block)?;
+ }
+ Node::BlockDef(ws1, name, _, ws2) => {
+ self.write_block(buf, Some(name), Ws(ws1.0, ws2.1))?;
+ }
+ Node::Include(ws, path) => {
+ size_hint += self.handle_include(ctx, buf, ws, path)?;
+ }
+ Node::Call(ws, scope, name, ref args) => {
+ size_hint += self.write_call(ctx, buf, ws, scope, name, args)?;
+ }
+ Node::Macro(_, ref m) => {
+ if level != AstLevel::Top {
+ return Err("macro blocks only allowed at the top level".into());
+ }
+ self.flush_ws(m.ws1);
+ self.prepare_ws(m.ws2);
+ }
+ Node::Raw(ws1, lws, val, rws, ws2) => {
+ self.handle_ws(ws1);
+ self.visit_lit(lws, val, rws);
+ self.handle_ws(ws2);
+ }
+ Node::Import(ws, _, _) => {
+ if level != AstLevel::Top {
+ return Err("import blocks only allowed at the top level".into());
+ }
+ self.handle_ws(ws);
+ }
+ Node::Extends(_) => {
+ if level != AstLevel::Top {
+ return Err("extend blocks only allowed at the top level".into());
+ }
+ // No whitespace handling: child template top-level is not used,
+ // except for the blocks defined in it.
+ }
+ Node::Break(ws) => {
+ self.handle_ws(ws);
+ self.write_buf_writable(buf)?;
+ buf.writeln("break;")?;
+ }
+ Node::Continue(ws) => {
+ self.handle_ws(ws);
+ self.write_buf_writable(buf)?;
+ buf.writeln("continue;")?;
+ }
+ }
+ }
+
+ if AstLevel::Top == level {
+ size_hint += self.write_buf_writable(buf)?;
+ }
+ Ok(size_hint)
+ }
+
+ fn write_cond(
+ &mut self,
+ ctx: &'a Context<'_>,
+ buf: &mut Buffer,
+ conds: &'a [Cond<'_>],
+ ws: Ws,
+ ) -> Result<usize, CompileError> {
+ let mut flushed = 0;
+ let mut arm_sizes = Vec::new();
+ let mut has_else = false;
+ for (i, &(cws, ref cond, ref nodes)) in conds.iter().enumerate() {
+ self.handle_ws(cws);
+ flushed += self.write_buf_writable(buf)?;
+ if i > 0 {
+ self.locals.pop();
+ }
+
+ self.locals.push();
+ let mut arm_size = 0;
+ if let Some(CondTest { target, expr }) = cond {
+ if i == 0 {
+ buf.write("if ");
+ } else {
+ buf.dedent()?;
+ buf.write("} else if ");
+ }
+
+ if let Some(target) = target {
+ let mut expr_buf = Buffer::new(0);
+ self.visit_expr(&mut expr_buf, expr)?;
+ buf.write("let ");
+ self.visit_target(buf, true, true, target);
+ buf.write(" = &(");
+ buf.write(&expr_buf.buf);
+ buf.write(")");
+ } else {
+ // The following syntax `*(&(...) as &bool)` is used to
+ // trigger Rust's automatic dereferencing, to coerce
+ // e.g. `&&&&&bool` to `bool`. First `&(...) as &bool`
+ // coerces e.g. `&&&bool` to `&bool`. Then `*(&bool)`
+ // finally dereferences it to `bool`.
+ buf.write("*(&(");
+ let expr_code = self.visit_expr_root(expr)?;
+ buf.write(&expr_code);
+ buf.write(") as &bool)");
+ }
+ } else {
+ buf.dedent()?;
+ buf.write("} else");
+ has_else = true;
+ }
+
+ buf.writeln(" {")?;
+
+ arm_size += self.handle(ctx, nodes, buf, AstLevel::Nested)?;
+ arm_sizes.push(arm_size);
+ }
+ self.handle_ws(ws);
+ flushed += self.write_buf_writable(buf)?;
+ buf.writeln("}")?;
+
+ self.locals.pop();
+
+ if !has_else {
+ arm_sizes.push(0);
+ }
+ Ok(flushed + median(&mut arm_sizes))
+ }
+
+ #[allow(clippy::too_many_arguments)]
+ fn write_match(
+ &mut self,
+ ctx: &'a Context<'_>,
+ buf: &mut Buffer,
+ ws1: Ws,
+ expr: &Expr<'_>,
+ arms: &'a [When<'_>],
+ ws2: Ws,
+ ) -> Result<usize, CompileError> {
+ self.flush_ws(ws1);
+ let flushed = self.write_buf_writable(buf)?;
+ let mut arm_sizes = Vec::new();
+
+ let expr_code = self.visit_expr_root(expr)?;
+ buf.writeln(&format!("match &{} {{", expr_code))?;
+
+ let mut arm_size = 0;
+ for (i, arm) in arms.iter().enumerate() {
+ let &(ws, ref target, ref body) = arm;
+ self.handle_ws(ws);
+
+ if i > 0 {
+ arm_sizes.push(arm_size + self.write_buf_writable(buf)?);
+
+ buf.writeln("}")?;
+ self.locals.pop();
+ }
+
+ self.locals.push();
+ self.visit_target(buf, true, true, target);
+ buf.writeln(" => {")?;
+
+ arm_size = self.handle(ctx, body, buf, AstLevel::Nested)?;
+ }
+
+ self.handle_ws(ws2);
+ arm_sizes.push(arm_size + self.write_buf_writable(buf)?);
+ buf.writeln("}")?;
+ self.locals.pop();
+
+ buf.writeln("}")?;
+
+ Ok(flushed + median(&mut arm_sizes))
+ }
+
+ #[allow(clippy::too_many_arguments)]
+ fn write_loop(
+ &mut self,
+ ctx: &'a Context<'_>,
+ buf: &mut Buffer,
+ loop_block: &'a Loop<'_>,
+ ) -> Result<usize, CompileError> {
+ self.handle_ws(loop_block.ws1);
+ self.locals.push();
+
+ let expr_code = self.visit_expr_root(&loop_block.iter)?;
+
+ let flushed = self.write_buf_writable(buf)?;
+ buf.writeln("{")?;
+ buf.writeln("let mut _did_loop = false;")?;
+ match loop_block.iter {
+ Expr::Range(_, _, _) => buf.writeln(&format!("let _iter = {};", expr_code)),
+ Expr::Array(..) => buf.writeln(&format!("let _iter = {}.iter();", expr_code)),
+ // If `iter` is a call then we assume it's something that returns
+ // an iterator. If not then the user can explicitly add the needed
+ // call without issues.
+ Expr::Call(..) | Expr::Index(..) => {
+ buf.writeln(&format!("let _iter = ({}).into_iter();", expr_code))
+ }
+ // If accessing `self` then it most likely needs to be
+ // borrowed, to prevent an attempt of moving.
+ _ if expr_code.starts_with("self.") => {
+ buf.writeln(&format!("let _iter = (&{}).into_iter();", expr_code))
+ }
+ // If accessing a field then it most likely needs to be
+ // borrowed, to prevent an attempt of moving.
+ Expr::Attr(..) => buf.writeln(&format!("let _iter = (&{}).into_iter();", expr_code)),
+ // Otherwise, we borrow `iter` assuming that it implements `IntoIterator`.
+ _ => buf.writeln(&format!("let _iter = ({}).into_iter();", expr_code)),
+ }?;
+ if let Some(cond) = &loop_block.cond {
+ self.locals.push();
+ buf.write("let _iter = _iter.filter(|");
+ self.visit_target(buf, true, true, &loop_block.var);
+ buf.write("| -> bool {");
+ self.visit_expr(buf, cond)?;
+ buf.writeln("});")?;
+ self.locals.pop();
+ }
+
+ self.locals.push();
+ buf.write("for (");
+ self.visit_target(buf, true, true, &loop_block.var);
+ buf.writeln(", _loop_item) in ::askama::helpers::TemplateLoop::new(_iter) {")?;
+
+ buf.writeln("_did_loop = true;")?;
+ let mut size_hint1 = self.handle(ctx, &loop_block.body, buf, AstLevel::Nested)?;
+ self.handle_ws(loop_block.ws2);
+ size_hint1 += self.write_buf_writable(buf)?;
+ self.locals.pop();
+ buf.writeln("}")?;
+
+ buf.writeln("if !_did_loop {")?;
+ self.locals.push();
+ let mut size_hint2 = self.handle(ctx, &loop_block.else_block, buf, AstLevel::Nested)?;
+ self.handle_ws(loop_block.ws3);
+ size_hint2 += self.write_buf_writable(buf)?;
+ self.locals.pop();
+ buf.writeln("}")?;
+
+ buf.writeln("}")?;
+
+ Ok(flushed + ((size_hint1 * 3) + size_hint2) / 2)
+ }
+
+ fn write_call(
+ &mut self,
+ ctx: &'a Context<'_>,
+ buf: &mut Buffer,
+ ws: Ws,
+ scope: Option<&str>,
+ name: &str,
+ args: &[Expr<'_>],
+ ) -> Result<usize, CompileError> {
+ if name == "super" {
+ return self.write_block(buf, None, ws);
+ }
+
+ let (def, own_ctx) = match scope {
+ Some(s) => {
+ let path = ctx.imports.get(s).ok_or_else(|| {
+ CompileError::from(format!("no import found for scope {:?}", s))
+ })?;
+ let mctx = self.contexts.get(path.as_path()).ok_or_else(|| {
+ CompileError::from(format!("context for {:?} not found", path))
+ })?;
+ let def = mctx.macros.get(name).ok_or_else(|| {
+ CompileError::from(format!("macro {:?} not found in scope {:?}", name, s))
+ })?;
+ (def, mctx)
+ }
+ None => {
+ let def = ctx
+ .macros
+ .get(name)
+ .ok_or_else(|| CompileError::from(format!("macro {:?} not found", name)))?;
+ (def, ctx)
+ }
+ };
+
+ self.flush_ws(ws); // Cannot handle_ws() here: whitespace from macro definition comes first
+ self.locals.push();
+ self.write_buf_writable(buf)?;
+ buf.writeln("{")?;
+ self.prepare_ws(def.ws1);
+
+ let mut names = Buffer::new(0);
+ let mut values = Buffer::new(0);
+ let mut is_first_variable = true;
+ for (i, arg) in def.args.iter().enumerate() {
+ let expr = args.get(i).ok_or_else(|| {
+ CompileError::from(format!("macro {:?} takes more than {} arguments", name, i))
+ })?;
+
+ match expr {
+ // If `expr` is already a form of variable then
+ // don't reintroduce a new variable. This is
+ // to avoid moving non-copyable values.
+ Expr::Var(name) => {
+ let var = self.locals.resolve_or_self(name);
+ self.locals.insert(arg, LocalMeta::with_ref(var));
+ }
+ Expr::Attr(obj, attr) => {
+ let mut attr_buf = Buffer::new(0);
+ self.visit_attr(&mut attr_buf, obj, attr)?;
+
+ let var = self.locals.resolve(&attr_buf.buf).unwrap_or(attr_buf.buf);
+ self.locals.insert(arg, LocalMeta::with_ref(var));
+ }
+ // Everything else still needs to become variables,
+ // to avoid having the same logic be executed
+ // multiple times, e.g. in the case of macro
+ // parameters being used multiple times.
+ _ => {
+ if is_first_variable {
+ is_first_variable = false
+ } else {
+ names.write(", ");
+ values.write(", ");
+ }
+ names.write(arg);
+
+ values.write("(");
+ values.write(&self.visit_expr_root(expr)?);
+ values.write(")");
+ self.locals.insert_with_default(arg);
+ }
+ }
+ }
+
+ debug_assert_eq!(names.buf.is_empty(), values.buf.is_empty());
+ if !names.buf.is_empty() {
+ buf.writeln(&format!("let ({}) = ({});", names.buf, values.buf))?;
+ }
+
+ let mut size_hint = self.handle(own_ctx, &def.nodes, buf, AstLevel::Nested)?;
+
+ self.flush_ws(def.ws2);
+ size_hint += self.write_buf_writable(buf)?;
+ buf.writeln("}")?;
+ self.locals.pop();
+ self.prepare_ws(ws);
+ Ok(size_hint)
+ }
+
+ fn handle_include(
+ &mut self,
+ ctx: &'a Context<'_>,
+ buf: &mut Buffer,
+ ws: Ws,
+ path: &str,
+ ) -> Result<usize, CompileError> {
+ self.flush_ws(ws);
+ self.write_buf_writable(buf)?;
+ let path = self
+ .input
+ .config
+ .find_template(path, Some(&self.input.path))?;
+ let src = get_template_source(&path)?;
+ let nodes = parse(&src, self.input.syntax)?;
+
+ // Make sure the compiler understands that the generated code depends on the template file.
+ {
+ let path = path.to_str().unwrap();
+ buf.writeln(
+ &quote! {
+ include_bytes!(#path);
+ }
+ .to_string(),
+ )?;
+ }
+
+ let size_hint = {
+ // Since nodes must not outlive the Generator, we instantiate
+ // a nested Generator here to handle the include's nodes.
+ let mut gen = self.child();
+ let mut size_hint = gen.handle(ctx, &nodes, buf, AstLevel::Nested)?;
+ size_hint += gen.write_buf_writable(buf)?;
+ size_hint
+ };
+ self.prepare_ws(ws);
+ Ok(size_hint)
+ }
+
+ fn write_let_decl(
+ &mut self,
+ buf: &mut Buffer,
+ ws: Ws,
+ var: &'a Target<'_>,
+ ) -> Result<(), CompileError> {
+ self.handle_ws(ws);
+ self.write_buf_writable(buf)?;
+ buf.write("let ");
+ self.visit_target(buf, false, true, var);
+ buf.writeln(";")
+ }
+
+ fn is_shadowing_variable(&self, var: &Target<'a>) -> Result<bool, CompileError> {
+ match var {
+ Target::Name(name) => {
+ let name = normalize_identifier(name);
+ match self.locals.get(&name) {
+ // declares a new variable
+ None => Ok(false),
+ // an initialized variable gets shadowed
+ Some(meta) if meta.initialized => Ok(true),
+ // initializes a variable that was introduced in a LetDecl before
+ _ => Ok(false),
+ }
+ }
+ Target::Tuple(_, targets) => {
+ for target in targets {
+ match self.is_shadowing_variable(target) {
+ Ok(false) => continue,
+ outcome => return outcome,
+ }
+ }
+ Ok(false)
+ }
+ Target::Struct(_, named_targets) => {
+ for (_, target) in named_targets {
+ match self.is_shadowing_variable(target) {
+ Ok(false) => continue,
+ outcome => return outcome,
+ }
+ }
+ Ok(false)
+ }
+ _ => Err("literals are not allowed on the left-hand side of an assignment".into()),
+ }
+ }
+
+ fn write_let(
+ &mut self,
+ buf: &mut Buffer,
+ ws: Ws,
+ var: &'a Target<'_>,
+ val: &Expr<'_>,
+ ) -> Result<(), CompileError> {
+ self.handle_ws(ws);
+ let mut expr_buf = Buffer::new(0);
+ self.visit_expr(&mut expr_buf, val)?;
+
+ let shadowed = self.is_shadowing_variable(var)?;
+ if shadowed {
+ // Need to flush the buffer if the variable is being shadowed,
+ // to ensure the old variable is used.
+ self.write_buf_writable(buf)?;
+ }
+ if shadowed
+ || !matches!(var, &Target::Name(_))
+ || matches!(var, Target::Name(name) if self.locals.get(name).is_none())
+ {
+ buf.write("let ");
+ }
+
+ self.visit_target(buf, true, true, var);
+ buf.writeln(&format!(" = {};", &expr_buf.buf))
+ }
+
+ // If `name` is `Some`, this is a call to a block definition, and we have to find
+ // the first block for that name from the ancestry chain. If name is `None`, this
+ // is from a `super()` call, and we can get the name from `self.super_block`.
+ fn write_block(
+ &mut self,
+ buf: &mut Buffer,
+ name: Option<&'a str>,
+ outer: Ws,
+ ) -> Result<usize, CompileError> {
+ // Flush preceding whitespace according to the outer WS spec
+ self.flush_ws(outer);
+
+ let prev_block = self.super_block;
+ let cur = match (name, prev_block) {
+ // The top-level context contains a block definition
+ (Some(cur_name), None) => (cur_name, 0),
+ // A block definition contains a block definition of the same name
+ (Some(cur_name), Some((prev_name, _))) if cur_name == prev_name => {
+ return Err(format!("cannot define recursive blocks ({})", cur_name).into());
+ }
+ // A block definition contains a definition of another block
+ (Some(cur_name), Some((_, _))) => (cur_name, 0),
+ // `super()` was called inside a block
+ (None, Some((prev_name, gen))) => (prev_name, gen + 1),
+ // `super()` is called from outside a block
+ (None, None) => return Err("cannot call 'super()' outside block".into()),
+ };
+ self.super_block = Some(cur);
+
+ // Get the block definition from the heritage chain
+ let heritage = self
+ .heritage
+ .as_ref()
+ .ok_or_else(|| CompileError::from("no block ancestors available"))?;
+ let (ctx, def) = heritage.blocks[cur.0].get(cur.1).ok_or_else(|| {
+ CompileError::from(match name {
+ None => format!("no super() block found for block '{}'", cur.0),
+ Some(name) => format!("no block found for name '{}'", name),
+ })
+ })?;
+
+ // Get the nodes and whitespace suppression data from the block definition
+ let (ws1, nodes, ws2) = if let Node::BlockDef(ws1, _, nodes, ws2) = def {
+ (ws1, nodes, ws2)
+ } else {
+ unreachable!()
+ };
+
+ // Handle inner whitespace suppression spec and process block nodes
+ self.prepare_ws(*ws1);
+ self.locals.push();
+ let size_hint = self.handle(ctx, nodes, buf, AstLevel::Block)?;
+
+ if !self.locals.is_current_empty() {
+ // Need to flush the buffer before popping the variable stack
+ self.write_buf_writable(buf)?;
+ }
+
+ self.locals.pop();
+ self.flush_ws(*ws2);
+
+ // Restore original block context and set whitespace suppression for
+ // succeeding whitespace according to the outer WS spec
+ self.super_block = prev_block;
+ self.prepare_ws(outer);
+ Ok(size_hint)
+ }
+
+ fn write_expr(&mut self, ws: Ws, s: &'a Expr<'a>) {
+ self.handle_ws(ws);
+ self.buf_writable.push(Writable::Expr(s));
+ }
+
+ // Write expression buffer and empty
+ fn write_buf_writable(&mut self, buf: &mut Buffer) -> Result<usize, CompileError> {
+ if self.buf_writable.is_empty() {
+ return Ok(0);
+ }
+
+ if self
+ .buf_writable
+ .iter()
+ .all(|w| matches!(w, Writable::Lit(_)))
+ {
+ let mut buf_lit = Buffer::new(0);
+ for s in mem::take(&mut self.buf_writable) {
+ if let Writable::Lit(s) = s {
+ buf_lit.write(s);
+ };
+ }
+ buf.writeln(&format!("writer.write_str({:#?})?;", &buf_lit.buf))?;
+ return Ok(buf_lit.buf.len());
+ }
+
+ let mut size_hint = 0;
+ let mut buf_format = Buffer::new(0);
+ let mut buf_expr = Buffer::new(buf.indent + 1);
+ let mut expr_cache = HashMap::with_capacity(self.buf_writable.len());
+ for s in mem::take(&mut self.buf_writable) {
+ match s {
+ Writable::Lit(s) => {
+ buf_format.write(&s.replace('{', "{{").replace('}', "}}"));
+ size_hint += s.len();
+ }
+ Writable::Expr(s) => {
+ use self::DisplayWrap::*;
+ let mut expr_buf = Buffer::new(0);
+ let wrapped = self.visit_expr(&mut expr_buf, s)?;
+ let expression = match wrapped {
+ Wrapped => expr_buf.buf,
+ Unwrapped => format!(
+ "::askama::MarkupDisplay::new_unsafe(&({}), {})",
+ expr_buf.buf, self.input.escaper
+ ),
+ };
+
+ use std::collections::hash_map::Entry;
+ let id = match expr_cache.entry(expression.clone()) {
+ Entry::Occupied(e) => *e.get(),
+ Entry::Vacant(e) => {
+ let id = self.named;
+ self.named += 1;
+
+ buf_expr.write(&format!("expr{} = ", id));
+ buf_expr.write("&");
+ buf_expr.write(&expression);
+ buf_expr.writeln(",")?;
+
+ e.insert(id);
+ id
+ }
+ };
+
+ buf_format.write(&format!("{{expr{}}}", id));
+ size_hint += 3;
+ }
+ }
+ }
+
+ buf.writeln("::std::write!(")?;
+ buf.indent();
+ buf.writeln("writer,")?;
+ buf.writeln(&format!("{:#?},", &buf_format.buf))?;
+ buf.writeln(buf_expr.buf.trim())?;
+ buf.dedent()?;
+ buf.writeln(")?;")?;
+ Ok(size_hint)
+ }
+
+ fn visit_lit(&mut self, lws: &'a str, val: &'a str, rws: &'a str) {
+ assert!(self.next_ws.is_none());
+ if !lws.is_empty() {
+ match self.skip_ws {
+ WhitespaceHandling::Suppress => {
+ self.skip_ws = WhitespaceHandling::Preserve;
+ }
+ _ if val.is_empty() => {
+ assert!(rws.is_empty());
+ self.next_ws = Some(lws);
+ }
+ WhitespaceHandling::Preserve => self.buf_writable.push(Writable::Lit(lws)),
+ WhitespaceHandling::Minimize => {
+ self.buf_writable
+ .push(Writable::Lit(match lws.contains('\n') {
+ true => "\n",
+ false => " ",
+ }))
+ }
+ }
+ }
+
+ if !val.is_empty() {
+ self.buf_writable.push(Writable::Lit(val));
+ }
+
+ if !rws.is_empty() {
+ self.next_ws = Some(rws);
+ }
+ }
+
+ fn write_comment(&mut self, ws: Ws) {
+ self.handle_ws(ws);
+ }
+
+ /* Visitor methods for expression types */
+
+ fn visit_expr_root(&mut self, expr: &Expr<'_>) -> Result<String, CompileError> {
+ let mut buf = Buffer::new(0);
+ self.visit_expr(&mut buf, expr)?;
+ Ok(buf.buf)
+ }
+
+ fn visit_expr(
+ &mut self,
+ buf: &mut Buffer,
+ expr: &Expr<'_>,
+ ) -> Result<DisplayWrap, CompileError> {
+ Ok(match *expr {
+ Expr::BoolLit(s) => self.visit_bool_lit(buf, s),
+ Expr::NumLit(s) => self.visit_num_lit(buf, s),
+ Expr::StrLit(s) => self.visit_str_lit(buf, s),
+ Expr::CharLit(s) => self.visit_char_lit(buf, s),
+ Expr::Var(s) => self.visit_var(buf, s),
+ Expr::Path(ref path) => self.visit_path(buf, path),
+ Expr::Array(ref elements) => self.visit_array(buf, elements)?,
+ Expr::Attr(ref obj, name) => self.visit_attr(buf, obj, name)?,
+ Expr::Index(ref obj, ref key) => self.visit_index(buf, obj, key)?,
+ Expr::Filter(name, ref args) => self.visit_filter(buf, name, args)?,
+ Expr::Unary(op, ref inner) => self.visit_unary(buf, op, inner)?,
+ Expr::BinOp(op, ref left, ref right) => self.visit_binop(buf, op, left, right)?,
+ Expr::Range(op, ref left, ref right) => self.visit_range(buf, op, left, right)?,
+ Expr::Group(ref inner) => self.visit_group(buf, inner)?,
+ Expr::Call(ref obj, ref args) => self.visit_call(buf, obj, args)?,
+ Expr::RustMacro(name, args) => self.visit_rust_macro(buf, name, args),
+ Expr::Try(ref expr) => self.visit_try(buf, expr.as_ref())?,
+ Expr::Tuple(ref exprs) => self.visit_tuple(buf, exprs)?,
+ })
+ }
+
+ fn visit_try(
+ &mut self,
+ buf: &mut Buffer,
+ expr: &Expr<'_>,
+ ) -> Result<DisplayWrap, CompileError> {
+ buf.write("::core::result::Result::map_err(");
+ self.visit_expr(buf, expr)?;
+ buf.write(", |err| ::askama::shared::Error::Custom(::core::convert::Into::into(err)))?");
+ Ok(DisplayWrap::Unwrapped)
+ }
+
+ fn visit_rust_macro(&mut self, buf: &mut Buffer, name: &str, args: &str) -> DisplayWrap {
+ buf.write(name);
+ buf.write("!(");
+ buf.write(args);
+ buf.write(")");
+
+ DisplayWrap::Unwrapped
+ }
+
+ #[cfg(not(feature = "markdown"))]
+ fn _visit_markdown_filter(
+ &mut self,
+ _buf: &mut Buffer,
+ _args: &[Expr<'_>],
+ ) -> Result<DisplayWrap, CompileError> {
+ Err("the `markdown` filter requires the `markdown` feature to be enabled".into())
+ }
+
+ #[cfg(feature = "markdown")]
+ fn _visit_markdown_filter(
+ &mut self,
+ buf: &mut Buffer,
+ args: &[Expr<'_>],
+ ) -> Result<DisplayWrap, CompileError> {
+ let (md, options) = match args {
+ [md] => (md, None),
+ [md, options] => (md, Some(options)),
+ _ => return Err("markdown filter expects no more than one option argument".into()),
+ };
+
+ buf.write(&format!(
+ "::askama::filters::markdown({}, ",
+ self.input.escaper
+ ));
+ self.visit_expr(buf, md)?;
+ match options {
+ Some(options) => {
+ buf.write(", ::core::option::Option::Some(");
+ self.visit_expr(buf, options)?;
+ buf.write(")");
+ }
+ None => buf.write(", ::core::option::Option::None"),
+ }
+ buf.write(")?");
+
+ Ok(DisplayWrap::Wrapped)
+ }
+
+ fn visit_filter(
+ &mut self,
+ buf: &mut Buffer,
+ mut name: &str,
+ args: &[Expr<'_>],
+ ) -> Result<DisplayWrap, CompileError> {
+ if matches!(name, "escape" | "e") {
+ self._visit_escape_filter(buf, args)?;
+ return Ok(DisplayWrap::Wrapped);
+ } else if name == "format" {
+ self._visit_format_filter(buf, args)?;
+ return Ok(DisplayWrap::Unwrapped);
+ } else if name == "fmt" {
+ self._visit_fmt_filter(buf, args)?;
+ return Ok(DisplayWrap::Unwrapped);
+ } else if name == "join" {
+ self._visit_join_filter(buf, args)?;
+ return Ok(DisplayWrap::Unwrapped);
+ } else if name == "markdown" {
+ return self._visit_markdown_filter(buf, args);
+ }
+
+ if name == "tojson" {
+ name = "json";
+ }
+
+ #[cfg(not(feature = "serde-json"))]
+ if name == "json" {
+ return Err("the `json` filter requires the `serde-json` feature to be enabled".into());
+ }
+ #[cfg(not(feature = "serde-yaml"))]
+ if name == "yaml" {
+ return Err("the `yaml` filter requires the `serde-yaml` feature to be enabled".into());
+ }
+
+ const FILTERS: [&str; 2] = ["safe", "yaml"];
+ if FILTERS.contains(&name) {
+ buf.write(&format!(
+ "::askama::filters::{}({}, ",
+ name, self.input.escaper
+ ));
+ } else if crate::BUILT_IN_FILTERS.contains(&name) {
+ buf.write(&format!("::askama::filters::{}(", name));
+ } else {
+ buf.write(&format!("filters::{}(", name));
+ }
+
+ self._visit_args(buf, args)?;
+ buf.write(")?");
+ Ok(match FILTERS.contains(&name) {
+ true => DisplayWrap::Wrapped,
+ false => DisplayWrap::Unwrapped,
+ })
+ }
+
+ fn _visit_escape_filter(
+ &mut self,
+ buf: &mut Buffer,
+ args: &[Expr<'_>],
+ ) -> Result<(), CompileError> {
+ if args.len() > 2 {
+ return Err("only two arguments allowed to escape filter".into());
+ }
+ let opt_escaper = match args.get(1) {
+ Some(Expr::StrLit(name)) => Some(*name),
+ Some(_) => return Err("invalid escaper type for escape filter".into()),
+ None => None,
+ };
+ let escaper = match opt_escaper {
+ Some(name) => self
+ .input
+ .config
+ .escapers
+ .iter()
+ .find_map(|(escapers, escaper)| escapers.contains(name).then(|| escaper))
+ .ok_or_else(|| CompileError::from("invalid escaper for escape filter"))?,
+ None => self.input.escaper,
+ };
+ buf.write("::askama::filters::escape(");
+ buf.write(escaper);
+ buf.write(", ");
+ self._visit_args(buf, &args[..1])?;
+ buf.write(")?");
+ Ok(())
+ }
+
+ fn _visit_format_filter(
+ &mut self,
+ buf: &mut Buffer,
+ args: &[Expr<'_>],
+ ) -> Result<(), CompileError> {
+ buf.write("format!(");
+ if let Some(Expr::StrLit(v)) = args.first() {
+ self.visit_str_lit(buf, v);
+ if args.len() > 1 {
+ buf.write(", ");
+ }
+ } else {
+ return Err("invalid expression type for format filter".into());
+ }
+ self._visit_args(buf, &args[1..])?;
+ buf.write(")");
+ Ok(())
+ }
+
+ fn _visit_fmt_filter(
+ &mut self,
+ buf: &mut Buffer,
+ args: &[Expr<'_>],
+ ) -> Result<(), CompileError> {
+ buf.write("format!(");
+ if let Some(Expr::StrLit(v)) = args.get(1) {
+ self.visit_str_lit(buf, v);
+ buf.write(", ");
+ } else {
+ return Err("invalid expression type for fmt filter".into());
+ }
+ self._visit_args(buf, &args[0..1])?;
+ if args.len() > 2 {
+ return Err("only two arguments allowed to fmt filter".into());
+ }
+ buf.write(")");
+ Ok(())
+ }
+
+ // Force type coercion on first argument to `join` filter (see #39).
+ fn _visit_join_filter(
+ &mut self,
+ buf: &mut Buffer,
+ args: &[Expr<'_>],
+ ) -> Result<(), CompileError> {
+ buf.write("::askama::filters::join((&");
+ for (i, arg) in args.iter().enumerate() {
+ if i > 0 {
+ buf.write(", &");
+ }
+ self.visit_expr(buf, arg)?;
+ if i == 0 {
+ buf.write(").into_iter()");
+ }
+ }
+ buf.write(")?");
+ Ok(())
+ }
+
+ fn _visit_args(&mut self, buf: &mut Buffer, args: &[Expr<'_>]) -> Result<(), CompileError> {
+ if args.is_empty() {
+ return Ok(());
+ }
+
+ for (i, arg) in args.iter().enumerate() {
+ if i > 0 {
+ buf.write(", ");
+ }
+
+ let borrow = !arg.is_copyable();
+ if borrow {
+ buf.write("&(");
+ }
+
+ match arg {
+ Expr::Call(left, _) if !matches!(left.as_ref(), Expr::Path(_)) => {
+ buf.writeln("{")?;
+ self.visit_expr(buf, arg)?;
+ buf.writeln("}")?;
+ }
+ _ => {
+ self.visit_expr(buf, arg)?;
+ }
+ }
+
+ if borrow {
+ buf.write(")");
+ }
+ }
+ Ok(())
+ }
+
+ fn visit_attr(
+ &mut self,
+ buf: &mut Buffer,
+ obj: &Expr<'_>,
+ attr: &str,
+ ) -> Result<DisplayWrap, CompileError> {
+ if let Expr::Var(name) = *obj {
+ if name == "loop" {
+ if attr == "index" {
+ buf.write("(_loop_item.index + 1)");
+ return Ok(DisplayWrap::Unwrapped);
+ } else if attr == "index0" {
+ buf.write("_loop_item.index");
+ return Ok(DisplayWrap::Unwrapped);
+ } else if attr == "first" {
+ buf.write("_loop_item.first");
+ return Ok(DisplayWrap::Unwrapped);
+ } else if attr == "last" {
+ buf.write("_loop_item.last");
+ return Ok(DisplayWrap::Unwrapped);
+ } else {
+ return Err("unknown loop variable".into());
+ }
+ }
+ }
+ self.visit_expr(buf, obj)?;
+ buf.write(&format!(".{}", normalize_identifier(attr)));
+ Ok(DisplayWrap::Unwrapped)
+ }
+
+ fn visit_index(
+ &mut self,
+ buf: &mut Buffer,
+ obj: &Expr<'_>,
+ key: &Expr<'_>,
+ ) -> Result<DisplayWrap, CompileError> {
+ buf.write("&");
+ self.visit_expr(buf, obj)?;
+ buf.write("[");
+ self.visit_expr(buf, key)?;
+ buf.write("]");
+ Ok(DisplayWrap::Unwrapped)
+ }
+
+ fn visit_call(
+ &mut self,
+ buf: &mut Buffer,
+ left: &Expr<'_>,
+ args: &[Expr<'_>],
+ ) -> Result<DisplayWrap, CompileError> {
+ match left {
+ Expr::Attr(left, method) if **left == Expr::Var("loop") => match *method {
+ "cycle" => match args {
+ [arg] => {
+ if matches!(arg, Expr::Array(arr) if arr.is_empty()) {
+ return Err("loop.cycle(…) cannot use an empty array".into());
+ }
+ buf.write("({");
+ buf.write("let _cycle = &(");
+ self.visit_expr(buf, arg)?;
+ buf.writeln(");")?;
+ buf.writeln("let _len = _cycle.len();")?;
+ buf.writeln("if _len == 0 {")?;
+ buf.writeln("return ::core::result::Result::Err(::askama::Error::Fmt(::core::fmt::Error));")?;
+ buf.writeln("}")?;
+ buf.writeln("_cycle[_loop_item.index % _len]")?;
+ buf.writeln("})")?;
+ }
+ _ => return Err("loop.cycle(…) expects exactly one argument".into()),
+ },
+ s => return Err(format!("unknown loop method: {:?}", s).into()),
+ },
+ left => {
+ match left {
+ Expr::Var(name) => match self.locals.resolve(name) {
+ Some(resolved) => buf.write(&resolved),
+ None => buf.write(&format!("(&self.{})", normalize_identifier(name))),
+ },
+ left => {
+ self.visit_expr(buf, left)?;
+ }
+ }
+
+ buf.write("(");
+ self._visit_args(buf, args)?;
+ buf.write(")");
+ }
+ }
+ Ok(DisplayWrap::Unwrapped)
+ }
+
+ fn visit_unary(
+ &mut self,
+ buf: &mut Buffer,
+ op: &str,
+ inner: &Expr<'_>,
+ ) -> Result<DisplayWrap, CompileError> {
+ buf.write(op);
+ self.visit_expr(buf, inner)?;
+ Ok(DisplayWrap::Unwrapped)
+ }
+
+ fn visit_range(
+ &mut self,
+ buf: &mut Buffer,
+ op: &str,
+ left: &Option<Box<Expr<'_>>>,
+ right: &Option<Box<Expr<'_>>>,
+ ) -> Result<DisplayWrap, CompileError> {
+ if let Some(left) = left {
+ self.visit_expr(buf, left)?;
+ }
+ buf.write(op);
+ if let Some(right) = right {
+ self.visit_expr(buf, right)?;
+ }
+ Ok(DisplayWrap::Unwrapped)
+ }
+
+ fn visit_binop(
+ &mut self,
+ buf: &mut Buffer,
+ op: &str,
+ left: &Expr<'_>,
+ right: &Expr<'_>,
+ ) -> Result<DisplayWrap, CompileError> {
+ self.visit_expr(buf, left)?;
+ buf.write(&format!(" {} ", op));
+ self.visit_expr(buf, right)?;
+ Ok(DisplayWrap::Unwrapped)
+ }
+
+ fn visit_group(
+ &mut self,
+ buf: &mut Buffer,
+ inner: &Expr<'_>,
+ ) -> Result<DisplayWrap, CompileError> {
+ buf.write("(");
+ self.visit_expr(buf, inner)?;
+ buf.write(")");
+ Ok(DisplayWrap::Unwrapped)
+ }
+
+ fn visit_tuple(
+ &mut self,
+ buf: &mut Buffer,
+ exprs: &[Expr<'_>],
+ ) -> Result<DisplayWrap, CompileError> {
+ buf.write("(");
+ for (index, expr) in exprs.iter().enumerate() {
+ if index > 0 {
+ buf.write(" ");
+ }
+ self.visit_expr(buf, expr)?;
+ buf.write(",");
+ }
+ buf.write(")");
+ Ok(DisplayWrap::Unwrapped)
+ }
+
+ fn visit_array(
+ &mut self,
+ buf: &mut Buffer,
+ elements: &[Expr<'_>],
+ ) -> Result<DisplayWrap, CompileError> {
+ buf.write("[");
+ for (i, el) in elements.iter().enumerate() {
+ if i > 0 {
+ buf.write(", ");
+ }
+ self.visit_expr(buf, el)?;
+ }
+ buf.write("]");
+ Ok(DisplayWrap::Unwrapped)
+ }
+
+ fn visit_path(&mut self, buf: &mut Buffer, path: &[&str]) -> DisplayWrap {
+ for (i, part) in path.iter().enumerate() {
+ if i > 0 {
+ buf.write("::");
+ }
+ buf.write(part);
+ }
+ DisplayWrap::Unwrapped
+ }
+
+ fn visit_var(&mut self, buf: &mut Buffer, s: &str) -> DisplayWrap {
+ if s == "self" {
+ buf.write(s);
+ return DisplayWrap::Unwrapped;
+ }
+
+ buf.write(normalize_identifier(&self.locals.resolve_or_self(s)));
+ DisplayWrap::Unwrapped
+ }
+
+ fn visit_bool_lit(&mut self, buf: &mut Buffer, s: &str) -> DisplayWrap {
+ buf.write(s);
+ DisplayWrap::Unwrapped
+ }
+
+ fn visit_str_lit(&mut self, buf: &mut Buffer, s: &str) -> DisplayWrap {
+ buf.write(&format!("\"{}\"", s));
+ DisplayWrap::Unwrapped
+ }
+
+ fn visit_char_lit(&mut self, buf: &mut Buffer, s: &str) -> DisplayWrap {
+ buf.write(&format!("'{}'", s));
+ DisplayWrap::Unwrapped
+ }
+
+ fn visit_num_lit(&mut self, buf: &mut Buffer, s: &str) -> DisplayWrap {
+ buf.write(s);
+ DisplayWrap::Unwrapped
+ }
+
+ fn visit_target(
+ &mut self,
+ buf: &mut Buffer,
+ initialized: bool,
+ first_level: bool,
+ target: &Target<'a>,
+ ) {
+ match target {
+ Target::Name("_") => {
+ buf.write("_");
+ }
+ Target::Name(name) => {
+ let name = normalize_identifier(name);
+ match initialized {
+ true => self.locals.insert(name, LocalMeta::initialized()),
+ false => self.locals.insert_with_default(name),
+ }
+ buf.write(name);
+ }
+ Target::Tuple(path, targets) => {
+ buf.write(&path.join("::"));
+ buf.write("(");
+ for target in targets {
+ self.visit_target(buf, initialized, false, target);
+ buf.write(",");
+ }
+ buf.write(")");
+ }
+ Target::Struct(path, targets) => {
+ buf.write(&path.join("::"));
+ buf.write(" { ");
+ for (name, target) in targets {
+ buf.write(normalize_identifier(name));
+ buf.write(": ");
+ self.visit_target(buf, initialized, false, target);
+ buf.write(",");
+ }
+ buf.write(" }");
+ }
+ Target::Path(path) => {
+ self.visit_path(buf, path);
+ }
+ Target::StrLit(s) => {
+ if first_level {
+ buf.write("&");
+ }
+ self.visit_str_lit(buf, s);
+ }
+ Target::NumLit(s) => {
+ if first_level {
+ buf.write("&");
+ }
+ self.visit_num_lit(buf, s);
+ }
+ Target::CharLit(s) => {
+ if first_level {
+ buf.write("&");
+ }
+ self.visit_char_lit(buf, s);
+ }
+ Target::BoolLit(s) => {
+ if first_level {
+ buf.write("&");
+ }
+ buf.write(s);
+ }
+ }
+ }
+
+ /* Helper methods for dealing with whitespace nodes */
+
+ // Combines `flush_ws()` and `prepare_ws()` to handle both trailing whitespace from the
+ // preceding literal and leading whitespace from the succeeding literal.
+ fn handle_ws(&mut self, ws: Ws) {
+ self.flush_ws(ws);
+ self.prepare_ws(ws);
+ }
+
+ fn should_trim_ws(&self, ws: Option<Whitespace>) -> WhitespaceHandling {
+ match ws {
+ Some(Whitespace::Suppress) => WhitespaceHandling::Suppress,
+ Some(Whitespace::Preserve) => WhitespaceHandling::Preserve,
+ Some(Whitespace::Minimize) => WhitespaceHandling::Minimize,
+ None => self.whitespace,
+ }
+ }
+
+ // If the previous literal left some trailing whitespace in `next_ws` and the
+ // prefix whitespace suppressor from the given argument, flush that whitespace.
+ // In either case, `next_ws` is reset to `None` (no trailing whitespace).
+ fn flush_ws(&mut self, ws: Ws) {
+ if self.next_ws.is_none() {
+ return;
+ }
+
+ // If `whitespace` is set to `suppress`, we keep the whitespace characters only if there is
+ // a `+` character.
+ match self.should_trim_ws(ws.0) {
+ WhitespaceHandling::Preserve => {
+ let val = self.next_ws.unwrap();
+ if !val.is_empty() {
+ self.buf_writable.push(Writable::Lit(val));
+ }
+ }
+ WhitespaceHandling::Minimize => {
+ let val = self.next_ws.unwrap();
+ if !val.is_empty() {
+ self.buf_writable
+ .push(Writable::Lit(match val.contains('\n') {
+ true => "\n",
+ false => " ",
+ }));
+ }
+ }
+ WhitespaceHandling::Suppress => {}
+ }
+ self.next_ws = None;
+ }
+
+ // Sets `skip_ws` to match the suffix whitespace suppressor from the given
+ // argument, to determine whether to suppress leading whitespace from the
+ // next literal.
+ fn prepare_ws(&mut self, ws: Ws) {
+ self.skip_ws = self.should_trim_ws(ws.1);
+ }
+}
+
+struct Buffer {
+ // The buffer to generate the code into
+ buf: String,
+ // The current level of indentation (in spaces)
+ indent: u8,
+ // Whether the output buffer is currently at the start of a line
+ start: bool,
+}
+
+impl Buffer {
+ fn new(indent: u8) -> Self {
+ Self {
+ buf: String::new(),
+ indent,
+ start: true,
+ }
+ }
+
+ fn writeln(&mut self, s: &str) -> Result<(), CompileError> {
+ if s == "}" {
+ self.dedent()?;
+ }
+ if !s.is_empty() {
+ self.write(s);
+ }
+ self.buf.push('\n');
+ if s.ends_with('{') {
+ self.indent();
+ }
+ self.start = true;
+ Ok(())
+ }
+
+ fn write(&mut self, s: &str) {
+ if self.start {
+ for _ in 0..(self.indent * 4) {
+ self.buf.push(' ');
+ }
+ self.start = false;
+ }
+ self.buf.push_str(s);
+ }
+
+ fn indent(&mut self) {
+ self.indent += 1;
+ }
+
+ fn dedent(&mut self) -> Result<(), CompileError> {
+ if self.indent == 0 {
+ return Err("dedent() called while indentation == 0".into());
+ }
+ self.indent -= 1;
+ Ok(())
+ }
+}
+
+#[derive(Clone, Default)]
+struct LocalMeta {
+ refs: Option<String>,
+ initialized: bool,
+}
+
+impl LocalMeta {
+ fn initialized() -> Self {
+ Self {
+ refs: None,
+ initialized: true,
+ }
+ }
+
+ fn with_ref(refs: String) -> Self {
+ Self {
+ refs: Some(refs),
+ initialized: true,
+ }
+ }
+}
+
+// type SetChain<'a, T> = MapChain<'a, T, ()>;
+
+#[derive(Debug)]
+struct MapChain<'a, K, V>
+where
+ K: cmp::Eq + hash::Hash,
+{
+ parent: Option<&'a MapChain<'a, K, V>>,
+ scopes: Vec<HashMap<K, V>>,
+}
+
+impl<'a, K: 'a, V: 'a> MapChain<'a, K, V>
+where
+ K: cmp::Eq + hash::Hash,
+{
+ fn new() -> MapChain<'a, K, V> {
+ MapChain {
+ parent: None,
+ scopes: vec![HashMap::new()],
+ }
+ }
+
+ fn with_parent<'p>(parent: &'p MapChain<'_, K, V>) -> MapChain<'p, K, V> {
+ MapChain {
+ parent: Some(parent),
+ scopes: vec![HashMap::new()],
+ }
+ }
+
+ /// Iterates the scopes in reverse and returns `Some(LocalMeta)`
+ /// from the first scope where `key` exists.
+ fn get(&self, key: &K) -> Option<&V> {
+ let scopes = self.scopes.iter().rev();
+ scopes
+ .filter_map(|set| set.get(key))
+ .next()
+ .or_else(|| self.parent.and_then(|set| set.get(key)))
+ }
+
+ fn is_current_empty(&self) -> bool {
+ self.scopes.last().unwrap().is_empty()
+ }
+
+ fn insert(&mut self, key: K, val: V) {
+ self.scopes.last_mut().unwrap().insert(key, val);
+
+ // Note that if `insert` returns `Some` then it implies
+ // an identifier is reused. For e.g. `{% macro f(a, a) %}`
+ // and `{% let (a, a) = ... %}` then this results in a
+ // generated template, which when compiled fails with the
+ // compile error "identifier `a` used more than once".
+ }
+
+ fn insert_with_default(&mut self, key: K)
+ where
+ V: Default,
+ {
+ self.insert(key, V::default());
+ }
+
+ fn push(&mut self) {
+ self.scopes.push(HashMap::new());
+ }
+
+ fn pop(&mut self) {
+ self.scopes.pop().unwrap();
+ assert!(!self.scopes.is_empty());
+ }
+}
+
+impl MapChain<'_, &str, LocalMeta> {
+ fn resolve(&self, name: &str) -> Option<String> {
+ let name = normalize_identifier(name);
+ self.get(&name).map(|meta| match &meta.refs {
+ Some(expr) => expr.clone(),
+ None => name.to_string(),
+ })
+ }
+
+ fn resolve_or_self(&self, name: &str) -> String {
+ let name = normalize_identifier(name);
+ self.resolve(name)
+ .unwrap_or_else(|| format!("self.{}", name))
+ }
+}
+
+fn median(sizes: &mut [usize]) -> usize {
+ sizes.sort_unstable();
+ if sizes.len() % 2 == 1 {
+ sizes[sizes.len() / 2]
+ } else {
+ (sizes[sizes.len() / 2 - 1] + sizes[sizes.len() / 2]) / 2
+ }
+}
+
+#[derive(Clone, PartialEq)]
+enum AstLevel {
+ Top,
+ Block,
+ Nested,
+}
+
+impl Copy for AstLevel {}
+
+#[derive(Clone)]
+enum DisplayWrap {
+ Wrapped,
+ Unwrapped,
+}
+
+impl Copy for DisplayWrap {}
+
+#[derive(Debug)]
+enum Writable<'a> {
+ Lit(&'a str),
+ Expr(&'a Expr<'a>),
+}
+
+// Identifiers to be replaced with raw identifiers, so as to avoid
+// collisions between template syntax and Rust's syntax. In particular
+// [Rust keywords](https://doc.rust-lang.org/reference/keywords.html)
+// should be replaced, since they're not reserved words in Askama
+// syntax but have a high probability of causing problems in the
+// generated code.
+//
+// This list excludes the Rust keywords *self*, *Self*, and *super*
+// because they are not allowed to be raw identifiers, and *loop*
+// because it's used something like a keyword in the template
+// language.
+static USE_RAW: [(&str, &str); 47] = [
+ ("as", "r#as"),
+ ("break", "r#break"),
+ ("const", "r#const"),
+ ("continue", "r#continue"),
+ ("crate", "r#crate"),
+ ("else", "r#else"),
+ ("enum", "r#enum"),
+ ("extern", "r#extern"),
+ ("false", "r#false"),
+ ("fn", "r#fn"),
+ ("for", "r#for"),
+ ("if", "r#if"),
+ ("impl", "r#impl"),
+ ("in", "r#in"),
+ ("let", "r#let"),
+ ("match", "r#match"),
+ ("mod", "r#mod"),
+ ("move", "r#move"),
+ ("mut", "r#mut"),
+ ("pub", "r#pub"),
+ ("ref", "r#ref"),
+ ("return", "r#return"),
+ ("static", "r#static"),
+ ("struct", "r#struct"),
+ ("trait", "r#trait"),
+ ("true", "r#true"),
+ ("type", "r#type"),
+ ("unsafe", "r#unsafe"),
+ ("use", "r#use"),
+ ("where", "r#where"),
+ ("while", "r#while"),
+ ("async", "r#async"),
+ ("await", "r#await"),
+ ("dyn", "r#dyn"),
+ ("abstract", "r#abstract"),
+ ("become", "r#become"),
+ ("box", "r#box"),
+ ("do", "r#do"),
+ ("final", "r#final"),
+ ("macro", "r#macro"),
+ ("override", "r#override"),
+ ("priv", "r#priv"),
+ ("typeof", "r#typeof"),
+ ("unsized", "r#unsized"),
+ ("virtual", "r#virtual"),
+ ("yield", "r#yield"),
+ ("try", "r#try"),
+];
+
+fn normalize_identifier(ident: &str) -> &str {
+ if let Some(word) = USE_RAW.iter().find(|x| x.0 == ident) {
+ word.1
+ } else {
+ ident
+ }
+}
generated by cgit (git 2.34.1) at 2024-11-21 23:49:38 +0000