perf(rome_js_formatter): Reduce the String allocations for Tokens

This PR reduces the amount of `String` allocation necessary for `FormatElement::Token`s by making use of the observation that most tokens match the text of a `SyntaxToken`. For example, identifiers, or punctuation tokens are kept by the formatter as is. This is even true for string literal tokens if they already use the right quotes. The way this is implemented is by introducing a new `SyntaxTokenText` that is `Send + Sync` and allows referencing a slice in a `SyntaxToken` without worrying about the `&str`'s lifetime. The PR further extends `FormatElement::Token` to make use of this new introduced `SyntaxTokenText`. This change reduces overall memory consumption and improves performance: ``` group format-element token ----- -------------- ----- formatter/checker.ts 1.04 250.2±5.03ms 10.4 MB/sec 1.00 239.5±1.76ms 10.9 MB/sec formatter/compiler.js 1.07 145.6±1.30ms 7.2 MB/sec 1.00 136.5±1.43ms 7.7 MB/sec formatter/d3.min.js 1.07 117.4±3.70ms 2.2 MB/sec 1.00 109.6±1.24ms 2.4 MB/sec formatter/dojo.js 1.03 7.4±0.15ms 9.2 MB/sec 1.00 7.2±0.03ms 9.5 MB/sec formatter/ios.d.ts 1.05 181.2±1.95ms 10.3 MB/sec 1.00 172.8±2.23ms 10.8 MB/sec formatter/jquery.min.js 1.02 29.1±0.55ms 2.8 MB/sec 1.00 28.5±0.07ms 2.9 MB/sec formatter/math.js 1.05 233.1±4.69ms 2.8 MB/sec 1.00 222.8±1.79ms 2.9 MB/sec formatter/parser.ts 1.03 5.3±0.15ms 9.2 MB/sec 1.00 5.1±0.01ms 9.5 MB/sec formatter/pixi.min.js 1.10 131.0±7.11ms 3.3 MB/sec 1.00 119.3±2.12ms 3.7 MB/sec formatter/react-dom.production.min.js 1.07 37.0±0.82ms 3.1 MB/sec 1.00 34.5±0.21ms 3.3 MB/sec formatter/react.production.min.js 1.08 1825.1±57.85µs 3.4 MB/sec 1.00 1683.8±30.49µs 3.7 MB/sec formatter/router.ts 1.02 3.7±0.09ms 16.2 MB/sec 1.00 3.6±0.01ms 16.6 MB/sec formatter/tex-chtml-full.js 1.05 288.3±5.19ms 3.2 MB/sec 1.00 273.4±1.29ms 3.3 MB/sec formatter/three.min.js 1.11 155.7±3.79ms 3.8 MB/sec 1.00 139.7±1.76ms 4.2 MB/sec formatter/typescript.js 1.04 945.2±6.64ms 10.1 MB/sec 1.00 909.3±7.16ms 10.4 MB/sec formatter/vue.global.prod.js 1.07 49.1±1.49ms 2.5 MB/sec 1.00 45.8±0.20ms 2.6 MB/sec ```
rome · Apr 16, 2022 · e10d648 · e10d648
1 parent 384026a
commit e10d648
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Showing 16 changed files with 271 additions and 80 deletions.
diff --git a/crates/rome_css_syntax/src/lib.rs b/crates/rome_css_syntax/src/lib.rs
@@ -4,7 +4,7 @@ mod syntax_node;
 
 pub use self::generated::*;
 pub use rome_rowan::{
-    SyntaxText, TextLen, TextRange, TextSize, TokenAtOffset, TriviaPieceKind, WalkEvent,
+    SyntaxNodeText, TextLen, TextRange, TextSize, TokenAtOffset, TriviaPieceKind, WalkEvent,
 };
 pub use syntax_node::*;
 

diff --git a/crates/rome_formatter/src/format_element.rs b/crates/rome_formatter/src/format_element.rs
@@ -1,6 +1,8 @@
 use crate::intersperse::{Intersperse, IntersperseFn};
-use crate::{format_elements, TextSize};
-use rome_rowan::{Language, SyntaxNode, SyntaxToken, SyntaxTriviaPieceComments};
+use crate::{format_elements, TextRange, TextSize};
+use rome_rowan::{
+    Language, SyntaxNode, SyntaxToken, SyntaxTokenText, SyntaxTriviaPieceComments, TextLen,
+};
 use std::borrow::Cow;
 use std::fmt::{self, Debug, Formatter};
 use std::ops::Deref;
@@ -1057,7 +1059,7 @@ impl List {
 }
 
 impl Deref for List {
-    type Target = Vec<FormatElement>;
+    type Target = [FormatElement];
 
     fn deref(&self) -> &Self::Target {
         &self.content
@@ -1125,6 +1127,13 @@ pub enum Token {
         // The position of the dynamic token in the unformatted source code
         source_position: TextSize,
     },
+    // A token that is taken 1:1 from the source code
+    SyntaxTokenSlice {
+        /// The start position of the token in the unformatted source code
+        source_position: TextSize,
+        /// The token text
+        slice: SyntaxTokenText,
+    },
 }
 
 impl Debug for Token {
@@ -1134,6 +1143,11 @@ impl Debug for Token {
         match self {
             Token::Static { text } => write!(fmt, "StaticToken({:?})", text),
             Token::Dynamic { text, .. } => write!(fmt, "DynamicToken({:?})", text),
+            Token::SyntaxTokenSlice {
+                slice: token_text, ..
+            } => {
+                write!(fmt, "SyntaxTokenSlice({:?})", token_text)
+            }
         }
     }
 }
@@ -1146,21 +1160,69 @@ impl Token {
 
     /// Create a token from a dynamic string and a range of the input source
     pub fn new_dynamic(text: String, position: TextSize) -> Self {
-        debug_assert!(!text.contains('\r'), "The content '{}' contains an unsupported '\\r' line terminator character but string tokens must only use line feeds '\\n' as line separator. Use '\\n' instead of '\\r' and '\\r\\n' to insert a line break in strings.", text);
+        Self::assert_no_newlines(&text);
         Self::Dynamic {
             text: text.into_boxed_str(),
             source_position: position,
         }
     }
 
+    /// Creates a token from a [Cow] that is a sub-slice over the text of a token.
+    ///
+    /// The `start` is the absolute start of the token in the source text.
+    ///
+    /// ## Returns
+    /// * [Token::Dynamic] if `text` is a [Cow::Owned] (text doesn't match syntax token text)
+    /// * [Token::SyntaxTokenSlice] if `text` is borrowed. Avoids allocating a new string.
+    pub fn from_syntax_token_cow_slice<L: Language>(
+        text: Cow<str>,
+        token: &SyntaxToken<L>,
+        start: TextSize,
+    ) -> Self {
+        Self::assert_no_newlines(&text);
+
+        match text {
+            Cow::Owned(text) => Self::new_dynamic(text, start),
+            Cow::Borrowed(text) => {
+                let range = TextRange::at(start, text.text_len());
+                debug_assert_eq!(
+                    text,
+                    &token.text()[range - token.text_range().start()],
+                    "The borrowed string doesn't match the specified token substring"
+                );
+                Token::new_syntax_token_slice(token, range)
+            }
+        }
+    }
+
+    /// Creates a new [Token] with a text backed by the string of [SyntaxToken]
+    pub fn new_syntax_token_slice<L: Language>(token: &SyntaxToken<L>, range: TextRange) -> Self {
+        let relative_range = range - token.text_range().start();
+        let slice = token.token_text().slice(relative_range);
+
+        Self::assert_no_newlines(&slice);
+
+        Self::SyntaxTokenSlice {
+            slice,
+            source_position: range.start(),
+        }
+    }
+
+    fn assert_no_newlines(text: &str) {
+        debug_assert!(!text.contains('\r'), "The content '{}' contains an unsupported '\\r' line terminator character but string tokens must only use line feeds '\\n' as line separator. Use '\\n' instead of '\\r' and '\\r\\n' to insert a line break in strings.", text);
+    }
+
     /// Get the range of the input source covered by this token,
     /// or None if the token was synthesized by the formatter
-    pub fn source(&self) -> Option<&TextSize> {
+    pub fn source_position(&self) -> Option<&TextSize> {
         match self {
             Token::Static { .. } => None,
             Token::Dynamic {
                 source_position, ..
             } => Some(source_position),
+            Token::SyntaxTokenSlice {
+                source_position, ..
+            } => Some(source_position),
         }
     }
 }
@@ -1180,10 +1242,9 @@ impl<L: Language> From<SyntaxToken<L>> for Token {
 
 impl<'a, L: Language> From<&'a SyntaxToken<L>> for Token {
     fn from(token: &'a SyntaxToken<L>) -> Self {
-        Self::new_dynamic(
-            token.text_trimmed().into(),
-            token.text_trimmed_range().start(),
-        )
+        let trimmed_range = token.text_trimmed_range();
+
+        Self::new_syntax_token_slice(token, trimmed_range)
     }
 }
 
@@ -1221,9 +1282,11 @@ pub fn normalize_newlines<const N: usize>(text: &str, terminators: [char; N]) ->
 
 impl<L: Language> From<SyntaxTriviaPieceComments<L>> for Token {
     fn from(trivia: SyntaxTriviaPieceComments<L>) -> Self {
-        Self::new_dynamic(
-            normalize_newlines(trivia.text().trim(), LINE_TERMINATORS).into_owned(),
-            trivia.text_range().start(),
+        let range = trivia.text_range();
+        Token::from_syntax_token_cow_slice(
+            normalize_newlines(trivia.text().trim(), LINE_TERMINATORS),
+            &trivia.as_piece().token(),
+            range.start(),
         )
     }
 }
@@ -1234,6 +1297,9 @@ impl Deref for Token {
         match self {
             Token::Static { text } => text,
             Token::Dynamic { text, .. } => text,
+            Token::SyntaxTokenSlice {
+                slice: token_text, ..
+            } => token_text.deref(),
         }
     }
 }

diff --git a/crates/rome_formatter/src/printer.rs b/crates/rome_formatter/src/printer.rs
@@ -171,7 +171,7 @@ impl<'a> Printer<'a> {
                     self.state.pending_space = false;
                 }
 
-                if let Some(source) = token.source() {
+                if let Some(source) = token.source_position() {
                     self.state.source_markers.push(SourceMarker {
                         source: *source,
                         dest: TextSize::from(self.state.buffer.len() as u32),

diff --git a/crates/rome_js_formatter/src/formatter.rs b/crates/rome_js_formatter/src/formatter.rs
@@ -428,12 +428,9 @@ impl Formatter {
         let skipped_trivia_range = skipped_trivia_range.expect("Only call this method for leading trivia containing at least one skipped token trivia.");
 
         // Format the skipped token trivia range
-        // Compute the offsets relative to the tokens text
-        let relative_skipped_range = skipped_trivia_range - token.text_range().start();
-        let text = &token.text()[relative_skipped_range];
-        elements.push(FormatElement::from(Token::new_dynamic(
-            text.to_string(),
-            skipped_trivia_range.start(),
+        elements.push(FormatElement::from(Token::new_syntax_token_slice(
+            token,
+            skipped_trivia_range,
         )));
 
         // `print_trailing_trivia_pieces` and `format_leading_trivia_pieces` remove any whitespace except
@@ -647,8 +644,9 @@ impl Formatter {
         }
 
         fn trivia_token<L: Language>(piece: SyntaxTriviaPiece<L>) -> Token {
-            Token::new_dynamic(
-                normalize_newlines(piece.text(), LINE_TERMINATORS).into_owned(),
+            Token::from_syntax_token_cow_slice(
+                normalize_newlines(piece.text(), LINE_TERMINATORS),
+                &piece.token(),
                 piece.text_range().start(),
             )
         }

diff --git a/crates/rome_js_formatter/src/utils/binary_like_expression.rs b/crates/rome_js_formatter/src/utils/binary_like_expression.rs
@@ -210,23 +210,16 @@ fn format_with_or_without_parenthesis(
     };
 
     let result = if operation_is_higher {
-        let formatted = if node.contains_comments() {
-            let (leading, content, trailing) = formatted_node.split_trivia();
-            format_elements![
-                leading,
-                group_elements(format_elements![
-                    token("("),
-                    soft_block_indent(format_elements![content, trailing]),
-                    token(")")
-                ])
-            ]
-        } else {
+        let (leading, content, trailing) = formatted_node.split_trivia();
+        let formatted = format_elements![
+            leading,
             group_elements(format_elements![
                 token("("),
-                soft_block_indent(formatted_node),
-                token(")"),
+                soft_block_indent(format_elements![content, trailing]),
+                token(")")
             ])
-        };
+        ];
+
         (formatted, true)
     } else {
         (formatted_node, false)

diff --git a/crates/rome_js_formatter/src/utils/mod.rs b/crates/rome_js_formatter/src/utils/mod.rs
@@ -388,8 +388,9 @@ pub(crate) fn format_template_chunk(
     // In template literals, the '\r' and '\r\n' line terminators are normalized to '\n'
     Ok(formatter.format_replaced(
         &chunk,
-        FormatElement::from(Token::new_dynamic(
-            normalize_newlines(chunk.text_trimmed(), ['\r']).into_owned(),
+        FormatElement::from(Token::from_syntax_token_cow_slice(
+            normalize_newlines(chunk.text_trimmed(), ['\r']),
+            &chunk,
             chunk.text_trimmed_range().start(),
         )),
     ))
@@ -615,16 +616,14 @@ pub(crate) fn format_string_literal_token(
         if quoted.starts_with(secondary_quote_char) && !quoted.contains(primary_quote_char) {
             let s = &quoted[1..quoted.len() - 1];
             let s = format!("{}{}{}", primary_quote_char, s, primary_quote_char);
-            match normalize_newlines(&s, ['\r']) {
-                Cow::Borrowed(_) => s,
-                Cow::Owned(s) => s,
-            }
+            Cow::Owned(normalize_newlines(&s, ['\r']).into_owned())
         } else {
-            normalize_newlines(quoted, ['\r']).into_owned()
+            normalize_newlines(quoted, ['\r'])
         };
 
     formatter.format_replaced(
         &token,
-        Token::new_dynamic(content, token.text_trimmed_range().start()).into(),
+        Token::from_syntax_token_cow_slice(content, &token, token.text_trimmed_range().start())
+            .into(),
     )
 }
diff --git a/crates/rome_js_syntax/src/expr_ext.rs b/crates/rome_js_syntax/src/expr_ext.rs
@@ -7,7 +7,7 @@ use crate::{
 };
 use crate::{JsPreUpdateExpression, JsSyntaxKind::*};
 use rome_rowan::{
-    AstNode, AstSeparatedList, NodeOrToken, SyntaxResult, SyntaxText, TextRange, TextSize,
+    AstNode, AstSeparatedList, NodeOrToken, SyntaxNodeText, SyntaxResult, TextRange, TextSize,
 };
 use std::cmp::Ordering;
 
@@ -371,7 +371,7 @@ impl JsNumberLiteralExpression {
 
 impl JsStringLiteralExpression {
     /// Get the inner text of a string not including the quotes
-    pub fn inner_string_text(&self) -> SyntaxText {
+    pub fn inner_string_text(&self) -> SyntaxNodeText {
         let start = self.syntax().text_range().start() + TextSize::from(1);
         let end_char = self
             .syntax()

diff --git a/crates/rome_js_syntax/src/lib.rs b/crates/rome_js_syntax/src/lib.rs
@@ -15,7 +15,7 @@ pub use self::generated::*;
 pub use expr_ext::*;
 pub use modifier_ext::*;
 pub use rome_rowan::{
-    SyntaxText, TextLen, TextRange, TextSize, TokenAtOffset, TriviaPieceKind, WalkEvent,
+    SyntaxNodeText, TextLen, TextRange, TextSize, TokenAtOffset, TriviaPieceKind, WalkEvent,
 };
 pub use stmt_ext::*;
 pub use syntax_node::*;

diff --git a/crates/rome_rowan/src/cursor/node.rs b/crates/rome_rowan/src/cursor/node.rs
@@ -1,7 +1,7 @@
 use crate::cursor::{free, GreenElement, NodeData, SyntaxElement, SyntaxToken, SyntaxTrivia};
 use crate::green::{Child, Children, Slot};
 use crate::{
-    Direction, GreenNode, GreenNodeData, NodeOrToken, RawSyntaxKind, SyntaxText, TokenAtOffset,
+    Direction, GreenNode, GreenNodeData, NodeOrToken, RawSyntaxKind, SyntaxNodeText, TokenAtOffset,
     WalkEvent,
 };
 use std::borrow::Cow;
@@ -173,13 +173,13 @@ impl SyntaxNode {
     }
 
     #[inline]
-    pub fn text(&self) -> SyntaxText {
-        SyntaxText::new(self.clone())
+    pub fn text(&self) -> SyntaxNodeText {
+        SyntaxNodeText::new(self.clone())
     }
 
     #[inline]
-    pub fn text_trimmed(&self) -> SyntaxText {
-        SyntaxText::with_range(self.clone(), self.text_trimmed_range())
+    pub fn text_trimmed(&self) -> SyntaxNodeText {
+        SyntaxNodeText::with_range(self.clone(), self.text_trimmed_range())
     }
 
     #[inline]

diff --git a/crates/rome_rowan/src/cursor/token.rs b/crates/rome_rowan/src/cursor/token.rs
@@ -1,5 +1,5 @@
 use crate::cursor::{free, GreenElement, NodeData, SyntaxElement, SyntaxNode, SyntaxTrivia};
-use crate::{Direction, GreenTokenData, RawSyntaxKind};
+use crate::{Direction, GreenTokenData, RawSyntaxKind, SyntaxTokenText};
 use std::hash::{Hash, Hasher};
 use std::{fmt, iter, ptr};
 use text_size::{TextRange, TextSize};
@@ -88,6 +88,11 @@ impl SyntaxToken {
         self.green().text()
     }
 
+    #[inline]
+    pub fn token_text(&self) -> SyntaxTokenText {
+        SyntaxTokenText::new(self.green().to_owned())
+    }
+
     #[inline]
     pub fn text_trimmed(&self) -> &str {
         self.green().text_trimmed()

diff --git a/crates/rome_rowan/src/lib.rs b/crates/rome_rowan/src/lib.rs
@@ -14,7 +14,7 @@ pub mod cursor;
 mod green;
 
 pub mod syntax;
-mod syntax_text;
+mod syntax_node_text;
 mod utility_types;
 
 #[allow(unsafe_code)]
@@ -27,6 +27,7 @@ mod serde_impls;
 #[allow(unsafe_code)]
 mod sll;
 mod syntax_factory;
+mod syntax_token_text;
 mod tree_builder;
 
 pub use text_size::{TextLen, TextRange, TextSize};
@@ -40,7 +41,8 @@ pub use crate::{
         TriviaPieceKind,
     },
     syntax_factory::*,
-    syntax_text::SyntaxText,
+    syntax_node_text::SyntaxNodeText,
+    syntax_token_text::SyntaxTokenText,
     tree_builder::{Checkpoint, TreeBuilder},
     utility_types::{Direction, NodeOrToken, TokenAtOffset, WalkEvent},
 };

diff --git a/crates/rome_rowan/src/syntax/node.rs b/crates/rome_rowan/src/syntax/node.rs
@@ -1,7 +1,7 @@
 use crate::syntax::element::SyntaxElement;
 use crate::syntax::SyntaxTrivia;
 use crate::{
-    cursor, Direction, GreenNode, Language, NodeOrToken, SyntaxKind, SyntaxList, SyntaxText,
+    cursor, Direction, GreenNode, Language, NodeOrToken, SyntaxKind, SyntaxList, SyntaxNodeText,
     SyntaxToken, TokenAtOffset, WalkEvent,
 };
 use std::fmt;
@@ -56,7 +56,7 @@ impl<L: Language> SyntaxNode<L> {
     /// });
     /// assert_eq!("\n\t let \t\ta; \t\t", node.text());
     /// ```
-    pub fn text(&self) -> SyntaxText {
+    pub fn text(&self) -> SyntaxNodeText {
         self.raw.text()
     }
 
@@ -84,7 +84,7 @@ impl<L: Language> SyntaxNode<L> {
     /// });
     /// assert_eq!("let \t\ta;", node.text_trimmed());
     /// ```
-    pub fn text_trimmed(&self) -> SyntaxText {
+    pub fn text_trimmed(&self) -> SyntaxNodeText {
         self.raw.text_trimmed()
     }