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-rw-r--r--askama_shared/src/generator.rs715
1 files changed, 715 insertions, 0 deletions
diff --git a/askama_shared/src/generator.rs b/askama_shared/src/generator.rs
new file mode 100644
index 0000000..82f3994
--- /dev/null
+++ b/askama_shared/src/generator.rs
@@ -0,0 +1,715 @@
+use parser::{self, Cond, Expr, Node, Target, WS};
+use path;
+
+use quote::{Tokens, ToTokens};
+
+use std::{cmp, hash, str};
+use std::path::Path;
+use std::collections::{HashMap, HashSet};
+
+use syn;
+
+pub fn generate(ast: &syn::DeriveInput, path: &Path, mut nodes: Vec<Node>) -> String {
+ let mut base: Option<Expr> = None;
+ let mut blocks = Vec::new();
+ let mut content = Vec::new();
+ let mut macros = HashMap::new();
+ for n in nodes.drain(..) {
+ match n {
+ Node::Extends(path) => {
+ match base {
+ Some(_) => panic!("multiple extend blocks found"),
+ None => { base = Some(path); },
+ }
+ },
+ Node::BlockDef(ws1, name, _, ws2) => {
+ blocks.push(n);
+ content.push(Node::Block(ws1, name, ws2));
+ },
+ Node::Macro(ws1, name, params, contents, ws2) => {
+ macros.insert(name, (ws1, name, params, contents, ws2));
+ },
+ _ => { content.push(n); },
+ }
+ }
+
+ let mut gen = Generator::default(&macros);
+ if !blocks.is_empty() {
+ let trait_name = trait_name_for_path(&base, path);
+ if base.is_none() {
+ gen.define_trait(&trait_name, &blocks);
+ } else {
+ let parent_type = get_parent_type(ast)
+ .expect("expected field '_parent' in extending template struct");
+ gen.deref_to_parent(ast, &parent_type);
+ }
+
+ let trait_nodes = if base.is_none() { Some(&content[..]) } else { None };
+ gen.impl_trait(ast, &trait_name, &blocks, trait_nodes);
+ gen.impl_template_for_trait(ast, base.is_some());
+ } else {
+ gen.impl_template(ast, &content);
+ }
+ gen.impl_display(ast);
+ if cfg!(feature = "iron") {
+ gen.impl_modifier_response(ast);
+ }
+ if cfg!(feature = "rocket") {
+ gen.impl_responder(ast, path);
+ }
+ gen.result()
+}
+
+fn trait_name_for_path(base: &Option<Expr>, path: &Path) -> String {
+ let rooted_path = match *base {
+ Some(Expr::StrLit(user_path)) => {
+ path::find_template_from_path(user_path, Some(path))
+ },
+ _ => path.to_path_buf(),
+ };
+
+ let mut res = String::new();
+ res.push_str("TraitFrom");
+ for c in rooted_path.to_string_lossy().chars() {
+ if c.is_alphanumeric() {
+ res.push(c);
+ } else {
+ res.push_str(&format!("{:x}", c as u32));
+ }
+ }
+ res
+}
+
+fn get_parent_type(ast: &syn::DeriveInput) -> Option<&syn::Ty> {
+ match ast.body {
+ syn::Body::Struct(ref data) => {
+ data.fields().iter().filter_map(|f| {
+ f.ident.as_ref().and_then(|name| {
+ if name.as_ref() == "_parent" {
+ Some(&f.ty)
+ } else {
+ None
+ }
+ })
+ })
+ },
+ _ => panic!("derive(Template) only works for struct items"),
+ }.next()
+}
+
+struct Generator<'a> {
+ buf: String,
+ indent: u8,
+ start: bool,
+ locals: SetChain<'a, &'a str>,
+ next_ws: Option<&'a str>,
+ skip_ws: bool,
+ macros: &'a MacroMap<'a>,
+}
+
+impl<'a> Generator<'a> {
+
+ fn new<'n>(macros: &'n MacroMap, locals: SetChain<'n, &'n str>, indent: u8) -> Generator<'n> {
+ Generator {
+ buf: String::new(),
+ indent: indent,
+ start: true,
+ locals: locals,
+ next_ws: None,
+ skip_ws: false,
+ macros: macros,
+ }
+ }
+
+ fn default<'n>(macros: &'n MacroMap) -> Generator<'n> {
+ Self::new(macros, SetChain::new(), 0)
+ }
+
+ fn child<'n>(&'n mut self) -> Generator<'n> {
+ let locals = SetChain::with_parent(&self.locals);
+ Self::new(self.macros, locals, self.indent)
+ }
+
+ /* Helper methods for writing to internal buffer */
+
+ fn indent(&mut self) {
+ self.indent += 1;
+ }
+
+ fn dedent(&mut self) {
+ self.indent -= 1;
+ }
+
+ 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 writeln(&mut self, s: &str) {
+ if s.is_empty() {
+ return;
+ }
+ if s == "}" {
+ self.dedent();
+ }
+ self.write(s);
+ if s.ends_with('{') {
+ self.indent();
+ }
+ self.buf.push('\n');
+ self.start = true;
+ }
+
+ /* Helper methods for dealing with whitespace nodes */
+
+ fn flush_ws(&mut self, ws: &WS) {
+ if self.next_ws.is_some() && !ws.0 {
+ let val = self.next_ws.unwrap();
+ if !val.is_empty() {
+ self.writeln(&format!("writer.write_str({:#?})?;",
+ val));
+ }
+ }
+ self.next_ws = None;
+ }
+
+ fn prepare_ws(&mut self, ws: &WS) {
+ self.skip_ws = ws.1;
+ }
+
+ fn handle_ws(&mut self, ws: &WS) {
+ self.flush_ws(ws);
+ self.prepare_ws(ws);
+ }
+
+ /* Visitor methods for expression types */
+
+ fn visit_num_lit(&mut self, s: &str) {
+ self.write(s);
+ }
+
+ fn visit_str_lit(&mut self, s: &str) {
+ self.write(&format!("\"{}\"", s));
+ }
+
+ fn visit_var(&mut self, s: &str) {
+ if self.locals.contains(s) {
+ self.write(s);
+ } else {
+ self.write(&format!("self.{}", s));
+ }
+ }
+
+ fn visit_attr(&mut self, obj: &Expr, attr: &str) {
+ if let Expr::Var(name) = *obj {
+ if name == "loop" {
+ self.write("_loop_index");
+ if attr == "index" {
+ self.write(" + 1");
+ return;
+ } else if attr == "index0" {
+ return;
+ } else {
+ panic!("unknown loop variable");
+ }
+ }
+ }
+ self.visit_expr(obj);
+ self.write(&format!(".{}", attr));
+ }
+
+ fn visit_filter(&mut self, name: &str, args: &[Expr]) {
+ if name == "format" {
+ self.write("format!(");
+ } else if BUILT_IN_FILTERS.contains(&name) {
+ self.write(&format!("::askama::filters::{}(&", name));
+ } else {
+ self.write(&format!("filters::{}(&", name));
+ }
+
+ for (i, arg) in args.iter().enumerate() {
+ if i > 0 {
+ self.write(", &");
+ }
+ self.visit_expr(arg);
+ }
+ self.write(")");
+ if name != "format" {
+ self.write("?");
+ }
+ }
+
+ fn visit_binop(&mut self, op: &str, left: &Expr, right: &Expr) {
+ self.visit_expr(left);
+ self.write(&format!(" {} ", op));
+ self.visit_expr(right);
+ }
+
+ fn visit_group(&mut self, inner: &Expr) {
+ self.write("(");
+ self.visit_expr(inner);
+ self.write(")");
+ }
+
+ fn visit_method_call(&mut self, obj: &Expr, method: &str, args: &[Expr]) {
+ self.visit_expr(obj);
+ self.write(&format!(".{}(", method));
+ for (i, arg) in args.iter().enumerate() {
+ if i > 0 {
+ self.write(", ");
+ }
+ self.visit_expr(arg);
+ }
+ self.write(")");
+ }
+
+ fn visit_expr(&mut self, expr: &Expr) {
+ match *expr {
+ Expr::NumLit(s) => self.visit_num_lit(s),
+ Expr::StrLit(s) => self.visit_str_lit(s),
+ Expr::Var(s) => self.visit_var(s),
+ Expr::Attr(ref obj, name) => self.visit_attr(obj, name),
+ Expr::Filter(name, ref args) => self.visit_filter(name, args),
+ Expr::BinOp(op, ref left, ref right) =>
+ self.visit_binop(op, left, right),
+ Expr::Group(ref inner) => self.visit_group(inner),
+ Expr::MethodCall(ref obj, method, ref args) =>
+ self.visit_method_call(obj, method, args),
+ }
+ }
+
+ fn visit_target_single<'t>(&mut self, name: &'t str) -> Vec<&'t str> {
+ vec![name]
+ }
+
+ fn visit_target<'t>(&mut self, target: &'t Target) -> Vec<&'t str> {
+ match *target {
+ Target::Name(s) => { self.visit_target_single(s) },
+ }
+ }
+
+ /* Helper methods for handling node types */
+
+ fn write_lit(&mut self, lws: &'a str, val: &str, rws: &'a str) {
+ assert!(self.next_ws.is_none());
+ if !lws.is_empty() {
+ if self.skip_ws {
+ self.skip_ws = false;
+ } else if val.is_empty() {
+ assert!(rws.is_empty());
+ self.next_ws = Some(lws);
+ } else {
+ self.writeln(&format!("writer.write_str({:#?})?;",
+ lws));
+ }
+ }
+ if !val.is_empty() {
+ self.writeln(&format!("writer.write_str({:#?})?;", val));
+ }
+ if !rws.is_empty() {
+ self.next_ws = Some(rws);
+ }
+ }
+
+ fn write_expr(&mut self, ws: &WS, s: &Expr) {
+ self.handle_ws(ws);
+ self.write("writer.write_fmt(format_args!(\"{}\", ");
+ self.visit_expr(s);
+ self.writeln("))?;");
+ }
+
+ fn write_call(&mut self, ws: &WS, name: &str, args: &[Expr]) {
+ self.handle_ws(ws);
+ let def = self.macros.get(name).expect(&format!("macro '{}' not found", name));
+ self.locals.push();
+ self.writeln("{");
+ self.prepare_ws(&def.0);
+ for (i, arg) in def.2.iter().enumerate() {
+ self.write(&format!("let {} = &", arg));
+ self.locals.insert(arg);
+ self.visit_expr(&args.get(i)
+ .expect(&format!("macro '{}' takes more than {} arguments", name, i)));
+ self.writeln(";");
+ }
+ self.handle(&def.3);
+ self.flush_ws(&def.4);
+ self.writeln("}");
+ self.locals.pop();
+ }
+
+ fn write_let_decl(&mut self, ws: &WS, var: &'a Target) {
+ self.handle_ws(ws);
+ self.write("let ");
+ match *var {
+ Target::Name(name) => {
+ self.locals.insert(name);
+ self.write(name);
+ },
+ }
+ self.writeln(";");
+ }
+
+ fn write_let(&mut self, ws: &WS, var: &'a Target, val: &Expr) {
+ self.handle_ws(ws);
+ match *var {
+ Target::Name(name) => {
+ if !self.locals.contains(name) {
+ self.write("let ");
+ self.locals.insert(name);
+ }
+ self.write(name);
+ },
+ }
+ self.write(" = ");
+ self.visit_expr(val);
+ self.writeln(";");
+ }
+
+ fn write_cond(&mut self, conds: &'a [Cond], ws: &WS) {
+ for (i, &(ref cws, ref cond, ref nodes)) in conds.iter().enumerate() {
+ self.handle_ws(cws);
+ match *cond {
+ Some(ref expr) => {
+ if i == 0 {
+ self.write("if ");
+ } else {
+ self.dedent();
+ self.write("} else if ");
+ }
+ self.visit_expr(expr);
+ },
+ None => {
+ self.dedent();
+ self.write("} else");
+ },
+ }
+ self.writeln(" {");
+ self.locals.push();
+ self.handle(nodes);
+ self.locals.pop();
+ }
+ self.handle_ws(ws);
+ self.writeln("}");
+ }
+
+ fn write_loop(&mut self, ws1: &WS, var: &'a Target, iter: &Expr,
+ body: &'a [Node], ws2: &WS) {
+ self.handle_ws(ws1);
+ self.locals.push();
+ self.write("for (_loop_index, ");
+ let targets = self.visit_target(var);
+ for name in &targets {
+ self.locals.insert(name);
+ self.write(name);
+ }
+ self.write(") in (&");
+ self.visit_expr(iter);
+ self.writeln(").into_iter().enumerate() {");
+
+ self.handle(body);
+ self.handle_ws(ws2);
+ self.writeln("}");
+ self.locals.pop();
+ }
+
+ fn write_block(&mut self, ws1: &WS, name: &str, ws2: &WS) {
+ self.flush_ws(ws1);
+ self.writeln(&format!("timpl.render_block_{}_into(writer)?;", name));
+ self.prepare_ws(ws2);
+ }
+
+ fn write_block_def(&mut self, ws1: &WS, name: &str, nodes: &'a [Node],
+ ws2: &WS) {
+ self.writeln("#[allow(unused_variables)]");
+ self.writeln(&format!(
+ "fn render_block_{}_into(&self, writer: &mut ::std::fmt::Write) \
+ -> ::askama::Result<()> {{",
+ name));
+ self.prepare_ws(ws1);
+
+ self.locals.push();
+ self.handle(nodes);
+ self.locals.pop();
+
+ self.flush_ws(ws2);
+ self.writeln("Ok(())");
+ self.writeln("}");
+ }
+
+ fn handle_include(&mut self, ws: &WS, path: &str) {
+ self.prepare_ws(ws);
+ let path = path::find_template_from_path(&path, None);
+ let src = path::get_template_source(&path);
+ let nodes = parser::parse(&src);
+ let nested = {
+ let mut gen = self.child();
+ gen.handle(&nodes);
+ gen.result()
+ };
+ self.buf.push_str(&nested);
+ self.flush_ws(ws);
+ }
+
+ fn handle(&mut self, nodes: &'a [Node]) {
+ for n in nodes {
+ match *n {
+ Node::Lit(lws, val, rws) => { self.write_lit(lws, val, rws); }
+ Node::Comment() => {},
+ Node::Expr(ref ws, ref val) => { self.write_expr(ws, val); },
+ Node::LetDecl(ref ws, ref var) => { self.write_let_decl(ws, var); },
+ Node::Let(ref ws, ref var, ref val) => { self.write_let(ws, var, val); },
+ Node::Cond(ref conds, ref ws) => {
+ self.write_cond(conds, ws);
+ },
+ Node::Loop(ref ws1, ref var, ref iter, ref body, ref ws2) => {
+ self.write_loop(ws1, var, iter, body, ws2);
+ },
+ Node::Block(ref ws1, name, ref ws2) => {
+ self.write_block(ws1, name, ws2);
+ },
+ Node::BlockDef(ref ws1, name, ref block_nodes, ref ws2) => {
+ self.write_block_def(ws1, name, block_nodes, ws2);
+ }
+ Node::Include(ref ws, ref path) => {
+ self.handle_include(ws, path);
+ },
+ Node::Call(ref ws, name, ref args) => self.write_call(ws, name, args),
+ Node::Macro(_, _, _, _, _) |
+ Node::Extends(_) => {
+ panic!("no extends or macros allowed in content");
+ },
+ }
+ }
+ }
+
+ // Writes header for the `impl` for `TraitFromPathName` or `Template`
+ // for the given context struct.
+ fn write_header(&mut self, ast: &syn::DeriveInput, target: &str, extra_anno: &[&str]) {
+ let mut full_anno = Tokens::new();
+ let mut orig_anno = Tokens::new();
+ let need_anno = ast.generics.lifetimes.len() > 0 ||
+ ast.generics.ty_params.len() > 0 ||
+ extra_anno.len() > 0;
+ if need_anno {
+ full_anno.append("<");
+ orig_anno.append("<");
+ }
+
+ let (mut full_sep, mut orig_sep) = (false, false);
+ for lt in &ast.generics.lifetimes {
+ if full_sep {
+ full_anno.append(",");
+ }
+ if orig_sep {
+ orig_anno.append(",");
+ }
+ lt.to_tokens(&mut full_anno);
+ lt.to_tokens(&mut orig_anno);
+ full_sep = true;
+ orig_sep = true;
+ }
+
+ for anno in extra_anno {
+ if full_sep {
+ full_anno.append(",");
+ }
+ full_anno.append(anno);
+ full_sep = true;
+ }
+
+ for param in &ast.generics.ty_params {
+ if full_sep {
+ full_anno.append(",");
+ }
+ if orig_sep {
+ orig_anno.append(",");
+ }
+ let mut impl_param = param.clone();
+ impl_param.default = None;
+ impl_param.to_tokens(&mut full_anno);
+ param.ident.to_tokens(&mut orig_anno);
+ full_sep = true;
+ orig_sep = true;
+ }
+
+ if need_anno {
+ full_anno.append(">");
+ orig_anno.append(">");
+ }
+
+ let mut where_clause = Tokens::new();
+ ast.generics.where_clause.to_tokens(&mut where_clause);
+ self.writeln(&format!("impl{} {} for {}{}{} {{",
+ full_anno.as_str(), target, ast.ident.as_ref(),
+ orig_anno.as_str(), where_clause.as_str()));
+ }
+
+ // Implement `Template` for the given context struct.
+ fn impl_template(&mut self, ast: &syn::DeriveInput, nodes: &'a [Node]) {
+ self.write_header(ast, "::askama::Template", &vec![]);
+ self.writeln("fn render_into(&self, writer: &mut ::std::fmt::Write) -> \
+ ::askama::Result<()> {");
+ self.handle(nodes);
+ self.flush_ws(&WS(false, false));
+ self.writeln("Ok(())");
+ self.writeln("}");
+ self.writeln("}");
+ }
+
+ // Implement `Display` for the given context struct.
+ fn impl_display(&mut self, ast: &syn::DeriveInput) {
+ self.write_header(ast, "::std::fmt::Display", &vec![]);
+ self.writeln("fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {");
+ self.writeln("self.render_into(f).map_err(|_| ::std::fmt::Error {})");
+ self.writeln("}");
+ self.writeln("}");
+ }
+
+ // Implement `Deref<Parent>` for an inheriting context struct.
+ fn deref_to_parent(&mut self, ast: &syn::DeriveInput, parent_type: &syn::Ty) {
+ self.write_header(ast, "::std::ops::Deref", &vec![]);
+ let mut tokens = Tokens::new();
+ parent_type.to_tokens(&mut tokens);
+ self.writeln(&format!("type Target = {};", tokens.as_str()));
+ self.writeln("fn deref(&self) -> &Self::Target {");
+ self.writeln("&self._parent");
+ self.writeln("}");
+ self.writeln("}");
+ }
+
+ // Implement `TraitFromPathName` for the given context struct.
+ fn impl_trait(&mut self, ast: &syn::DeriveInput, trait_name: &str,
+ blocks: &'a [Node], nodes: Option<&'a [Node]>) {
+ self.write_header(ast, &trait_name, &vec![]);
+ self.handle(blocks);
+
+ self.writeln("#[allow(unused_variables)]");
+ self.writeln(&format!(
+ "fn render_trait_into(&self, timpl: &{}, writer: &mut ::std::fmt::Write) \
+ -> ::askama::Result<()> {{",
+ trait_name));
+
+ if let Some(nodes) = nodes {
+ self.handle(nodes);
+ self.flush_ws(&WS(false, false));
+ } else {
+ self.writeln("self._parent.render_trait_into(self, writer)?;");
+ }
+
+ self.writeln("Ok(())");
+ self.writeln("}");
+ self.flush_ws(&WS(false, false));
+ self.writeln("}");
+ }
+
+ // Implement `Template` for templates that implement a template trait.
+ fn impl_template_for_trait(&mut self, ast: &syn::DeriveInput, derived: bool) {
+ self.write_header(ast, "::askama::Template", &vec![]);
+ self.writeln("fn render_into(&self, writer: &mut ::std::fmt::Write) \
+ -> ::askama::Result<()> {");
+ if derived {
+ self.writeln("self._parent.render_trait_into(self, writer)?;");
+ } else {
+ self.writeln("self.render_trait_into(self, writer)?;");
+ }
+ self.writeln("Ok(())");
+ self.writeln("}");
+ self.writeln("}");
+ }
+
+ // Defines the `TraitFromPathName` trait.
+ fn define_trait(&mut self, trait_name: &str, blocks: &'a [Node]) {
+ self.writeln(&format!("trait {} {{", &trait_name));
+ self.handle(blocks);
+ self.writeln(&format!(
+ "fn render_trait_into(&self, timpl: &{}, writer: &mut ::std::fmt::Write) \
+ -> ::askama::Result<()>;",
+ trait_name));
+ self.writeln("}");
+ }
+
+ // Implement iron's Modifier<Response> if enabled
+ fn impl_modifier_response(&mut self, ast: &syn::DeriveInput) {
+ self.write_header(ast, "::askama::iron::Modifier<::askama::iron::Response>", &vec![]);
+ self.writeln("fn modify(self, res: &mut ::askama::iron::Response) {");
+ self.writeln("res.body = Some(Box::new(self.render().unwrap().into_bytes()));");
+ self.writeln("}");
+ self.writeln("}");
+ }
+
+ // Implement Rocket's `Responder`.
+ fn impl_responder(&mut self, ast: &syn::DeriveInput, path: &Path) {
+ self.write_header(ast, "::askama::rocket::Responder<'r>", &vec!["'r"]);
+ self.writeln("fn respond_to(self, _: &::askama::rocket::Request) \
+ -> ::std::result::Result<\
+ ::askama::rocket::Response<'r>, ::askama::rocket::Status> {");
+ let ext = match path.extension() {
+ Some(s) => s.to_str().unwrap(),
+ None => "txt",
+ };
+ self.writeln("::askama::rocket::Response::build()");
+ self.indent();
+ self.writeln(&format!(".header(::askama::rocket::ContentType::from_extension({:?})\
+ .unwrap())", ext));
+ self.writeln(".sized_body(::std::io::Cursor::new(self.render().unwrap()))");
+ self.writeln(".ok()");
+ self.dedent();
+ self.writeln("}");
+ self.writeln("}");
+ }
+
+ fn result(self) -> String {
+ self.buf
+ }
+
+}
+
+struct SetChain<'a, T: 'a> where T: cmp::Eq + hash::Hash {
+ parent: Option<&'a SetChain<'a, T>>,
+ scopes: Vec<HashSet<T>>,
+}
+
+impl<'a, T: 'a> SetChain<'a, T> where T: cmp::Eq + hash::Hash {
+ fn new() -> SetChain<'a, T> {
+ SetChain { parent: None, scopes: vec![HashSet::new()] }
+ }
+ fn with_parent<'p>(parent: &'p SetChain<T>) -> SetChain<'p, T> {
+ SetChain { parent: Some(parent), scopes: vec![HashSet::new()] }
+ }
+ fn contains(&self, val: T) -> bool {
+ self.scopes.iter().rev().any(|set| set.contains(&val)) ||
+ match self.parent {
+ Some(set) => set.contains(val),
+ None => false,
+ }
+ }
+ fn insert(&mut self, val: T) {
+ self.scopes.last_mut().unwrap().insert(val);
+ }
+ fn push(&mut self) {
+ self.scopes.push(HashSet::new());
+ }
+ fn pop(&mut self) {
+ self.scopes.pop().unwrap();
+ assert!(self.scopes.len() > 0);
+ }
+}
+
+type MacroMap<'a> = HashMap<&'a str, (WS, &'a str, Vec<&'a str>, Vec<Node<'a>>, WS)>;
+
+const BUILT_IN_FILTERS: [&str; 9] = [
+ "e",
+ "escape",
+ "format",
+ "lower",
+ "lowercase",
+ "trim",
+ "upper",
+ "uppercase",
+ "json", // Optional feature; reserve the name anyway
+];
generated by cgit (git 2.34.1) at 2024-11-21 23:11:04 +0000