perf(styled-components): Do not allocate if visitors are not used (#392)

swc-project · Jan 24, 2025 · 53bd1e6 · 53bd1e6
1 parent 5886faf
commit 53bd1e6
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Showing 8 changed files with 68 additions and 22 deletions.
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/packages/styled-components/CHANGELOG.md b/packages/styled-components/CHANGELOG.md
@@ -1,5 +1,11 @@
 # @swc/plugin-styled-components
 
+## 6.1.0
+
+### Minor Changes
+
+- d532813: Avoid allocation when not used
+
 ## 6.0.4
 
 ### Patch Changes

diff --git a/packages/styled-components/README.md b/packages/styled-components/README.md
@@ -28,6 +28,12 @@ Then update your `.swcrc` file like below:
 
 # @swc/plugin-styled-components
 
+## 6.1.0
+
+### Minor Changes
+
+- d532813: Avoid allocation when not used
+
 ## 6.0.4
 
 ### Patch Changes

diff --git a/packages/styled-components/package.json b/packages/styled-components/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@swc/plugin-styled-components",
-  "version": "6.0.4",
+  "version": "6.1.0",
   "description": "SWC plugin for styled-components",
   "main": "swc_plugin_styled_components.wasm",
   "scripts": {

diff --git a/packages/styled-components/src/lib.rs b/packages/styled-components/src/lib.rs
@@ -6,7 +6,7 @@ use styled_components::Config;
 use swc_common::{SourceMapper, Spanned};
 use swc_core::{
     common::FileName,
-    ecma::{ast::Program, visit::VisitMutWith},
+    ecma::ast::Program,
     plugin::{
         metadata::TransformPluginMetadataContextKind,
         plugin_transform,
@@ -33,10 +33,9 @@ fn styled_components(mut program: Program, data: TransformPluginProgramMetadata)
     let pos = data.source_map.lookup_char_pos(program.span().lo);
     let hash = pos.file.src_hash;
 
-    let mut pass =
-        styled_components::styled_components(file_name, hash, config, PluginCommentsProxy);
+    let pass = styled_components::styled_components(file_name, hash, config, PluginCommentsProxy);
 
-    program.visit_mut_with(&mut pass);
+    program.mutate(pass);
 
     program
 }
diff --git a/packages/styled-components/transform/Cargo.toml b/packages/styled-components/transform/Cargo.toml
@@ -12,7 +12,7 @@ homepage     = { workspace = true }
 license      = { workspace = true }
 repository   = { workspace = true }
 rust-version = { workspace = true }
-version      = "0.98.1"
+version      = "0.98.2"
 
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

diff --git a/packages/styled-components/transform/src/lib.rs b/packages/styled-components/transform/src/lib.rs
@@ -5,8 +5,7 @@ use std::{cell::RefCell, rc::Rc, sync::Arc};
 use serde::Deserialize;
 use swc_atoms::JsWord;
 use swc_common::{comments::Comments, pass::Optional, FileName};
-use swc_ecma_ast::Pass;
-use swc_ecma_visit::VisitMut;
+use swc_ecma_ast::{Pass, Program};
 
 pub use crate::{
     utils::{analyze, analyzer, State},
@@ -77,7 +76,7 @@ pub fn styled_components<C>(
     src_file_hash: u128,
     config: Config,
     comments: C,
-) -> impl Pass + VisitMut
+) -> impl Pass
 where
     C: Comments,
 {
@@ -90,18 +89,47 @@ where
             enabled: config.css_prop,
             visitor: transpile_css_prop(state.clone()),
         },
-        Optional {
-            enabled: config.minify,
-            visitor: minify(state.clone()),
-        },
-        display_name_and_id(file_name, src_file_hash, config.clone(), state.clone()),
-        Optional {
-            enabled: config.transpile_template_literals,
-            visitor: template_literals(state.clone()),
-        },
-        Optional {
-            enabled: config.pure,
-            visitor: pure_annotation(comments, state),
+        MayWork {
+            pass: (
+                Optional {
+                    enabled: config.minify,
+                    visitor: minify(state.clone()),
+                },
+                display_name_and_id(file_name, src_file_hash, config.clone(), state.clone()),
+                Optional {
+                    enabled: config.transpile_template_literals,
+                    visitor: template_literals(state.clone()),
+                },
+                Optional {
+                    enabled: config.pure,
+                    visitor: pure_annotation(comments, state.clone()),
+                },
+            ),
+            state,
         },
     )
 }
+
+struct MayWork<P>
+where
+    P: Pass,
+{
+    pass: P,
+    state: Rc<RefCell<State>>,
+}
+
+impl<P> Pass for MayWork<P>
+where
+    P: Pass,
+{
+    fn process(&mut self, p: &mut Program) {
+        {
+            let state = self.state.borrow();
+            if !state.need_work() {
+                return;
+            }
+        }
+
+        self.pass.process(p);
+    }
+}
diff --git a/packages/styled-components/transform/src/utils/mod.rs b/packages/styled-components/transform/src/utils/mod.rs
@@ -67,6 +67,13 @@ pub struct State {
 }
 
 impl State {
+    pub(crate) fn need_work(&self) -> bool {
+        self.styled_required.is_some()
+            || self.imported_local_name.is_some()
+            || !self.imported_local_named.is_empty()
+            || self.imported_local_ns.is_some()
+    }
+
     pub(crate) fn is_styled(&self, tag: &Expr) -> bool {
         if let Expr::Call(CallExpr {
             callee: Callee::Expr(callee),