Use custom Arc backed input

Signed-off-by: Marcel Müller <neikos@neikos.email>

src/ast/mod.rs

@@ -24,8 +24,8 @@ pub struct TemplateAst<'input> {
     root: Vec<TemplateAstExpr<'input>>,
 }
 
-impl<'input> TemplateAst<'input> {
-    pub fn root(&self) -> &[TemplateAstExpr<'input>] {
+impl TemplateAst<'_> {
+    pub fn root(&self) -> &[TemplateAstExpr<'_>] {
         &self.root
     }
 }
@@ -73,22 +73,22 @@ impl ModalError for AstError {
     }
 }
 
-impl<'input> FromRecoverableError<Input<'input>, AstError> for AstError {
+impl FromRecoverableError<Input<'_>, AstError> for AstError {
     fn from_recoverable_error(
-        token_start: &<Input<'input> as winnow::stream::Stream>::Checkpoint,
-        _err_start: &<Input<'input> as winnow::stream::Stream>::Checkpoint,
-        input: &Input<'input>,
+        token_start: &<Input as winnow::stream::Stream>::Checkpoint,
+        _err_start: &<Input as winnow::stream::Stream>::Checkpoint,
+        input: &Input,
         mut e: AstError,
     ) -> Self {
         e
     }
 }
 
-impl<'input> AddContext<Input<'input>, AstError> for AstError {
+impl AddContext<Input<'_>, AstError> for AstError {
     fn add_context(
         mut self,
-        _input: &Input<'input>,
-        _token_start: &<Input<'input> as Stream>::Checkpoint,
+        _input: &Input,
+        _token_start: &<Input as Stream>::Checkpoint,
         context: AstError,
     ) -> Self {
         self.message = context.message.or(self.message);
@@ -97,10 +97,10 @@ impl<'input> AddContext<Input<'input>, AstError> for AstError {
     }
 }
 
-impl<'input> ParserError<Input<'input>> for AstError {
+impl ParserError<Input<'_>> for AstError {
     type Inner = AstError;
 
-    fn from_input(_input: &Input<'input>) -> Self {
+    fn from_input(_input: &Input<'_>) -> Self {
         AstError::ctx()
     }
 
@@ -117,24 +117,22 @@ impl<'input> ParserError<Input<'input>> for AstError {
 pub struct AstFailure {}
 
 impl AstFailure {
-    fn from_errors(_errors: Vec<AstError>, _input: &[TemplateToken<'_>]) -> AstFailure {
+    fn from_errors(_errors: Vec<AstError>, _input: &[TemplateToken]) -> AstFailure {
         AstFailure {}
     }
 }
 
-type Input<'input> = Recoverable<TokenSlice<'input, TemplateToken<'input>>, AstError>;
+type Input<'input> = Recoverable<TokenSlice<'input, TemplateToken>, AstError>;
 
-impl<'i> Parser<Input<'i>, TemplateToken<'i>, AstError> for TokenKind {
-    fn parse_next(&mut self, input: &mut Input<'i>) -> winnow::Result<TemplateToken<'i>, AstError> {
+impl<'input> Parser<Input<'input>, TemplateToken, AstError> for TokenKind {
+    fn parse_next(&mut self, input: &mut Input<'input>) -> winnow::Result<TemplateToken, AstError> {
         winnow::token::literal(*self)
             .parse_next(input)
             .map(|t| t[0].clone())
     }
 }
 
-pub fn parse<'input>(
-    input: &'input [TemplateToken<'input>],
-) -> Result<TemplateAst<'input>, AstFailure> {
+pub fn parse(input: &[TemplateToken]) -> Result<TemplateAst<'_>, AstFailure> {
     let (_remaining, val, errors) = parse_ast.recoverable_parse(TokenSlice::new(input));
 
     if errors.is_empty()
@@ -148,15 +146,15 @@ pub fn parse<'input>(
 
 #[derive(Debug, Clone)]
 pub enum TemplateAstExpr<'input> {
-    StaticContent(TemplateToken<'input>),
+    StaticContent(TemplateToken),
     Interpolation {
-        prev_whitespace: Option<TemplateToken<'input>>,
-        wants_output: Option<TemplateToken<'input>>,
+        prev_whitespace: Option<TemplateToken>,
+        wants_output: Option<TemplateToken>,
         expression: Box<TemplateAstExpr<'input>>,
-        post_whitespace: Option<TemplateToken<'input>>,
+        post_whitespace: Option<TemplateToken>,
     },
-    VariableAccess(TemplateToken<'input>),
-    Invalid(&'input [TemplateToken<'input>]),
+    VariableAccess(TemplateToken),
+    Invalid(&'input [TemplateToken]),
 }
 
 fn parse_ast<'input>(input: &mut Input<'input>) -> Result<Vec<TemplateAstExpr<'input>>, AstError> {

src/emit/mod.rs

@@ -1,4 +1,5 @@
 use crate::ast::TemplateAstExpr;
+use crate::input::TempleInput;
 
 pub struct EmitMachine {
     current_index: usize,
@@ -23,10 +24,19 @@ pub struct VariableSlot {
 
 #[derive(Debug)]
 pub enum Instruction {
-    AppendContent { content: String },
-    LoadFromContextToSlot { name: String, slot: VariableSlot },
-    EmitFromSlot { slot: VariableSlot },
-    PushScope { inherit_parent: bool },
+    AppendContent {
+        content: TempleInput,
+    },
+    LoadFromContextToSlot {
+        name: TempleInput,
+        slot: VariableSlot,
+    },
+    EmitFromSlot {
+        slot: VariableSlot,
+    },
+    PushScope {
+        inherit_parent: bool,
+    },
     Abort,
 }
 
@@ -42,11 +52,15 @@ pub fn emit_machine(input: crate::ast::TemplateAst<'_>) -> Vec<Instruction> {
     eval
 }
 
-fn emit_ast_expr(machine: &mut EmitMachine, eval: &mut Vec<Instruction>, ast: &TemplateAstExpr<'_>) {
+fn emit_ast_expr(
+    machine: &mut EmitMachine,
+    eval: &mut Vec<Instruction>,
+    ast: &TemplateAstExpr<'_>,
+) {
     match ast {
         TemplateAstExpr::StaticContent(template_token) => {
             eval.push(Instruction::AppendContent {
-                content: template_token.source().to_string(),
+                content: template_token.source().clone(),
             });
         }
         TemplateAstExpr::Interpolation {
@@ -57,7 +71,7 @@ fn emit_ast_expr(machine: &mut EmitMachine, eval: &mut Vec<Instruction>, ast: &T
         } => {
             if let Some(ws) = prev_whitespace {
                 eval.push(Instruction::AppendContent {
-                    content: ws.source().to_string(),
+                    content: ws.source().clone(),
                 });
             }
 
@@ -70,7 +84,7 @@ fn emit_ast_expr(machine: &mut EmitMachine, eval: &mut Vec<Instruction>, ast: &T
 
             if let Some(ws) = post_whitespace {
                 eval.push(Instruction::AppendContent {
-                    content: ws.source().to_string(),
+                    content: ws.source().clone(),
                 });
             }
         }
@@ -89,7 +103,7 @@ fn emit_expr(
     match expression {
         TemplateAstExpr::VariableAccess(template_token) => {
             eval.push(Instruction::LoadFromContextToSlot {
-                name: template_token.source().to_string(),
+                name: template_token.source().clone(),
                 slot: emit_slot,
             });
         }

src/eval/mod.rs

@@ -5,11 +5,12 @@ use thiserror::Error;
 
 use crate::Context;
 use crate::emit::Instruction;
+use crate::input::TempleInput;
 
 #[derive(Debug, Error, Display)]
 enum EvalError {
     /// An unknown variable was encountered: .0
-    UnknownVariable(String),
+    UnknownVariable(TempleInput),
     /// An explicit abort was requested
     ExplicitAbort,
 }
@@ -25,7 +26,7 @@ fn execute(instructions: &[Instruction], global_context: &Context) -> Result<Str
             Instruction::LoadFromContextToSlot { name, slot } => {
                 let value = global_context
                     .values
-                    .get(name)
+                    .get(name.as_str())
                     .ok_or(EvalError::UnknownVariable(name.clone()))?;
 
                 scopes.insert(*slot, value.clone());

src/input.rs

@@ -0,0 +1,194 @@
+use std::ops::Deref;
+use std::ops::Range;
+use std::sync::Arc;
+
+use winnow::stream::Compare;
+use winnow::stream::FindSlice;
+use winnow::stream::Offset;
+use winnow::stream::Stream;
+use winnow::stream::StreamIsPartial;
+
+#[derive(Clone, PartialEq, Eq)]
+pub struct TempleInput {
+    backing: Arc<str>,
+    range: Range<usize>,
+}
+
+impl std::fmt::Debug for TempleInput {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "\"{}\"", self.as_str())
+    }
+}
+
+impl From<&str> for TempleInput {
+    fn from(value: &str) -> Self {
+        let backing = Arc::from(value.to_string());
+        let range = 0..value.len();
+
+        TempleInput { backing, range }
+    }
+}
+
+impl FindSlice<&str> for TempleInput {
+    fn find_slice(&self, substr: &str) -> Option<core::ops::Range<usize>> {
+        self.as_str().find_slice(substr)
+    }
+}
+
+impl Compare<&str> for TempleInput {
+    fn compare(&self, t: &str) -> winnow::stream::CompareResult {
+        self.as_str().compare(t)
+    }
+}
+
+impl Deref for TempleInput {
+    type Target = str;
+
+    fn deref(&self) -> &Self::Target {
+        &self.backing[self.range.clone()]
+    }
+}
+
+impl TempleInput {
+    pub fn as_str(&self) -> &str {
+        self.deref()
+    }
+}
+
+impl Offset for TempleInput {
+    fn offset_from(&self, start: &Self) -> usize {
+        self.as_str().offset_from(&start.as_str())
+    }
+}
+
+pub struct TempleInputIter {
+    idx: usize,
+    input: TempleInput,
+}
+
+impl Iterator for TempleInputIter {
+    type Item = (usize, char);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let val = self.input.as_str().char_indices().nth(self.idx);
+        self.idx += 1;
+        val
+    }
+}
+
+impl StreamIsPartial for TempleInput {
+    type PartialState = ();
+
+    fn complete(&mut self) -> Self::PartialState {
+        // Always complete
+    }
+
+    fn restore_partial(&mut self, _state: Self::PartialState) {}
+
+    fn is_partial_supported() -> bool {
+        false
+    }
+}
+
+impl Stream for TempleInput {
+    type Token = char;
+
+    type Slice = TempleInput;
+
+    type IterOffsets = TempleInputIter;
+
+    type Checkpoint = TempleInput;
+
+    fn iter_offsets(&self) -> Self::IterOffsets {
+        TempleInputIter {
+            idx: 0,
+            input: self.clone(),
+        }
+    }
+
+    fn eof_offset(&self) -> usize {
+        self.len()
+    }
+
+    fn next_token(&mut self) -> Option<Self::Token> {
+        let c = self.chars().next()?;
+
+        self.range.start += c.len_utf8();
+        Some(c)
+    }
+
+    fn peek_token(&self) -> Option<Self::Token> {
+        self.chars().next()
+    }
+
+    fn offset_for<P>(&self, predicate: P) -> Option<usize>
+    where
+        P: Fn(Self::Token) -> bool,
+    {
+        self.as_str().offset_for(predicate)
+    }
+
+    fn offset_at(&self, tokens: usize) -> Result<usize, winnow::error::Needed> {
+        self.as_str().offset_at(tokens)
+    }
+
+    fn next_slice(&mut self, offset: usize) -> Self::Slice {
+        let mut next = self.clone();
+
+        self.range.start += offset;
+        next.range.end = self.range.start;
+
+        next
+    }
+
+    fn peek_slice(&self, offset: usize) -> Self::Slice {
+        let mut next = self.clone();
+        next.range.end = self.range.start + offset;
+        next
+    }
+
+    fn checkpoint(&self) -> Self::Checkpoint {
+        self.clone()
+    }
+
+    fn reset(&mut self, checkpoint: &Self::Checkpoint) {
+        self.range = checkpoint.range.clone();
+    }
+
+    fn raw(&self) -> &dyn core::fmt::Debug {
+        self
+    }
+
+    fn trace(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        f.write_str(self.as_str())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use winnow::stream::Stream;
+
+    use crate::input::TempleInput;
+
+    #[test]
+    fn check_stream_impl() {
+        let mut stream = TempleInput::from("checking");
+
+        let checkpoint = stream.checkpoint();
+
+        assert_eq!(stream.peek_token(), Some('c'));
+        assert_eq!(stream.next_token(), Some('c'));
+        let next_slice = stream.next_slice(4);
+        assert_eq!(next_slice.as_str(), "heck");
+        assert_eq!(stream.peek_token(), Some('i'));
+
+        stream.reset(&checkpoint);
+        assert_eq!(stream.peek_token(), Some('c'));
+
+        let peek = stream.peek_slice(4);
+        assert_eq!(peek.as_str(), "chec");
+
+        let eof_offset = stream.eof_offset();
+        assert_eq!(eof_offset, 8);
+    }
+}

src/lib.rs

@@ -9,6 +9,7 @@ pub mod ast;
 pub mod emit;
 pub mod eval;
 pub mod parser;
+mod input;
 
 #[derive(Debug, Error, Display)]
 pub enum TempleError {

src/parser/mod.rs

@@ -31,9 +31,10 @@ use winnow::token::take_until;
 use winnow::token::take_while;
 
 use crate::SourceSpan;
+use crate::input::TempleInput;
 use crate::resume_after_cut;
 
-type Input<'input> = Recoverable<LocatingSlice<&'input str>, ParseError>;
+type Input<'input> = Recoverable<LocatingSlice<TempleInput>, ParseError>;
 type PResult<'input, T> = Result<T, ParseError>;
 
 #[derive(Debug)]
@@ -177,12 +178,12 @@ impl<'input> ParserError<Input<'input>> for ParseError {
 }
 
 #[derive(Debug)]
-pub struct ParsedTemplate<'input> {
-    tokens: Vec<TemplateToken<'input>>,
+pub struct ParsedTemplate {
+    tokens: Vec<TemplateToken>,
 }
 
-impl<'input> ParsedTemplate<'input> {
-    pub fn tokens(&self) -> &[TemplateToken<'input>] {
+impl ParsedTemplate {
+    pub fn tokens(&self) -> &[TemplateToken] {
         &self.tokens
     }
 }
@@ -198,88 +199,86 @@ pub enum TokenKind {
     Invalid,
 }
 
-impl PartialEq<TokenKind> for TemplateToken<'_> {
+impl PartialEq<TokenKind> for TemplateToken {
     fn eq(&self, other: &TokenKind) -> bool {
         self.kind == *other
     }
 }
 
-impl winnow::stream::ContainsToken<&'_ TemplateToken<'_>> for TokenKind {
-    fn contains_token(&self, token: &'_ TemplateToken<'_>) -> bool {
+impl winnow::stream::ContainsToken<&'_ TemplateToken> for TokenKind {
+    fn contains_token(&self, token: &'_ TemplateToken) -> bool {
         *self == token.kind
     }
 }
 
-impl winnow::stream::ContainsToken<&'_ TemplateToken<'_>> for &'_ [TokenKind] {
-    fn contains_token(&self, token: &'_ TemplateToken<'_>) -> bool {
+impl winnow::stream::ContainsToken<&'_ TemplateToken> for &'_ [TokenKind] {
+    fn contains_token(&self, token: &'_ TemplateToken) -> bool {
         self.contains(&token.kind)
     }
 }
 
-impl<const LEN: usize> winnow::stream::ContainsToken<&'_ TemplateToken<'_>>
-    for &'_ [TokenKind; LEN]
-{
-    fn contains_token(&self, token: &'_ TemplateToken<'_>) -> bool {
+impl<const LEN: usize> winnow::stream::ContainsToken<&'_ TemplateToken> for &'_ [TokenKind; LEN] {
+    fn contains_token(&self, token: &'_ TemplateToken) -> bool {
         self.contains(&token.kind)
     }
 }
 
-impl<const LEN: usize> winnow::stream::ContainsToken<&'_ TemplateToken<'_>> for [TokenKind; LEN] {
-    fn contains_token(&self, token: &'_ TemplateToken<'_>) -> bool {
+impl<const LEN: usize> winnow::stream::ContainsToken<&'_ TemplateToken> for [TokenKind; LEN] {
+    fn contains_token(&self, token: &'_ TemplateToken) -> bool {
         self.contains(&token.kind)
     }
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
-pub struct TemplateToken<'input> {
+pub struct TemplateToken {
     kind: TokenKind,
-    source: &'input str,
+    source: TempleInput,
 }
 
-impl<'input> TemplateToken<'input> {
-    fn content(source: &'input str) -> Self {
+impl TemplateToken {
+    fn content(source: TempleInput) -> Self {
         TemplateToken {
             kind: TokenKind::Content,
             source,
         }
     }
 
-    fn left_delim(source: &'input str) -> Self {
+    fn left_delim(source: TempleInput) -> Self {
         TemplateToken {
             kind: TokenKind::LeftDelim,
             source,
         }
     }
 
-    fn right_delim(source: &'input str) -> Self {
+    fn right_delim(source: TempleInput) -> Self {
         TemplateToken {
             kind: TokenKind::RightDelim,
             source,
         }
     }
 
-    fn wants_output(source: &'input str) -> Self {
+    fn wants_output(source: TempleInput) -> Self {
         TemplateToken {
             kind: TokenKind::WantsOutput,
             source,
         }
     }
 
-    fn ident(source: &'input str) -> Self {
+    fn ident(source: TempleInput) -> Self {
         TemplateToken {
             kind: TokenKind::Ident,
             source,
         }
     }
 
-    fn whitespace(source: &'input str) -> Self {
+    fn whitespace(source: TempleInput) -> Self {
         TemplateToken {
             kind: TokenKind::Whitespace,
             source,
         }
     }
 
-    fn invalid(source: &'input str) -> Self {
+    fn invalid(source: TempleInput) -> Self {
         TemplateToken {
             kind: TokenKind::Invalid,
             source,
@@ -290,13 +289,14 @@ impl<'input> TemplateToken<'input> {
         self.kind
     }
 
-    pub fn source(&self) -> &'input str {
-        self.source
+    pub fn source(&self) -> TempleInput {
+        self.source.clone()
     }
 }
 
-pub fn parse(input: &str) -> Result<ParsedTemplate<'_>, ParseFailure> {
-    let (_remaining, val, errors) = parse_tokens.recoverable_parse(LocatingSlice::new(input));
+pub fn parse(input: &str) -> Result<ParsedTemplate, ParseFailure> {
+    let (_remaining, val, errors) =
+        parse_tokens.recoverable_parse(LocatingSlice::new(TempleInput::from(input)));
 
     if errors.is_empty()
         && let Some(val) = val
@@ -307,13 +307,13 @@ pub fn parse(input: &str) -> Result<ParsedTemplate<'_>, ParseFailure> {
     }
 }
 
-fn parse_tokens<'input>(input: &mut Input<'input>) -> PResult<'input, Vec<TemplateToken<'input>>> {
+fn parse_tokens<'input>(input: &mut Input<'input>) -> PResult<'input, Vec<TemplateToken>> {
     repeat_till(0.., alt((parse_interpolate, parse_content)), eof)
         .map(|(v, _): (Vec<_>, _)| v.into_iter().flatten().collect())
         .parse_next(input)
 }
 
-fn parse_content<'input>(input: &mut Input<'input>) -> PResult<'input, Vec<TemplateToken<'input>>> {
+fn parse_content<'input>(input: &mut Input<'input>) -> PResult<'input, Vec<TemplateToken>> {
     alt((
         repeat_till(1.., any, peek((multispace0, "{{"))).map(|((), _)| ()),
         rest.void(),
@@ -324,9 +324,7 @@ fn parse_content<'input>(input: &mut Input<'input>) -> PResult<'input, Vec<Templ
     .parse_next(input)
 }
 
-fn parse_interpolate<'input>(
-    input: &mut Input<'input>,
-) -> PResult<'input, Vec<TemplateToken<'input>>> {
+fn parse_interpolate<'input>(input: &mut Input<'input>) -> PResult<'input, Vec<TemplateToken>> {
     let prev_whitespace = opt(parse_whitespace).parse_next(input)?;
     let left_delim = "{{".map(TemplateToken::left_delim).parse_next(input)?;
     let wants_output = opt("=".map(TemplateToken::wants_output)).parse_next(input)?;
@@ -337,7 +335,9 @@ fn parse_interpolate<'input>(
     let (inside_tokens, _): (Vec<_>, _) = get_tokens
         .resume_after(recover)
         .with_taken()
-        .map(|(val, taken)| val.unwrap_or_else(|| (vec![TemplateToken::invalid(taken)], "")))
+        .map(|(val, taken)| {
+            val.unwrap_or_else(|| (vec![TemplateToken::invalid(taken)], TempleInput::from("")))
+        })
         .parse_next(input)?;
 
     let right_delim = "}}".map(TemplateToken::right_delim).parse_next(input)?;
@@ -354,9 +354,7 @@ fn parse_interpolate<'input>(
     Ok(tokens)
 }
 
-fn parse_interpolate_token<'input>(
-    input: &mut Input<'input>,
-) -> PResult<'input, TemplateToken<'input>> {
+fn parse_interpolate_token<'input>(input: &mut Input<'input>) -> PResult<'input, TemplateToken> {
     trace(
         "parse_interpolate_token",
         alt((parse_ident, parse_whitespace)),
@@ -364,7 +362,7 @@ fn parse_interpolate_token<'input>(
     .parse_next(input)
 }
 
-fn parse_whitespace<'input>(input: &mut Input<'input>) -> PResult<'input, TemplateToken<'input>> {
+fn parse_whitespace<'input>(input: &mut Input<'input>) -> PResult<'input, TemplateToken> {
     trace(
         "parse_whitespace",
         multispace1.map(TemplateToken::whitespace),
@@ -372,7 +370,7 @@ fn parse_whitespace<'input>(input: &mut Input<'input>) -> PResult<'input, Templa
     .parse_next(input)
 }
 
-fn parse_ident<'input>(input: &mut Input<'input>) -> PResult<'input, TemplateToken<'input>> {
+fn parse_ident<'input>(input: &mut Input<'input>) -> PResult<'input, TemplateToken> {
     resume_after_cut(
         terminated(
             ident.map(TemplateToken::ident),
@@ -390,7 +388,7 @@ fn parse_ident<'input>(input: &mut Input<'input>) -> PResult<'input, TemplateTok
     .parse_next(input)
 }
 
-fn ident<'input>(input: &mut Input<'input>) -> PResult<'input, &'input str> {
+fn ident<'input>(input: &mut Input<'input>) -> PResult<'input, TempleInput> {
     take_while(1.., char::is_alphanumeric).parse_next(input)
 }