From 0705452eb7ffb829364ea61b3f0ed17515ff113b Mon Sep 17 00:00:00 2001
From: Boshen <boshenc@gmail.com>
Date: Tue, 7 May 2024 23:41:30 +0800
Subject: [PATCH] feat(sourcemap): add "rayon" feature

---
 Cargo.lock                         |  1 +
 Cargo.toml                         |  2 ++
 crates/oxc_sourcemap/Cargo.toml    | 10 ++++++--
 crates/oxc_sourcemap/src/encode.rs | 38 +++++++++++++++++++++++-------
 tasks/benchmark/Cargo.toml         |  2 +-
 5 files changed, 41 insertions(+), 12 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index a9cd15306e3ba..1818bc05fe3dd 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1620,6 +1620,7 @@ name = "oxc_sourcemap"
 version = "0.12.5"
 dependencies = [
  "base64-simd",
+ "cfg-if",
  "rayon",
  "rustc-hash",
  "serde",
diff --git a/Cargo.toml b/Cargo.toml
index afd1ad2e90bdc..0737b7af4ac92 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -171,6 +171,8 @@ similar             = "2.5.0"
 textwrap            = "0.16.0"
 unicode-width       = "0.1.12"
 saphyr              = "0.0.1"
+base64-simd         = "0.8"
+cfg-if              = "1.0.0"
 
 [workspace.metadata.cargo-shear]
 ignored = ["napi", "oxc_traverse"]
diff --git a/crates/oxc_sourcemap/Cargo.toml b/crates/oxc_sourcemap/Cargo.toml
index 696ac0e4caa6e..0779dcad0824e 100644
--- a/crates/oxc_sourcemap/Cargo.toml
+++ b/crates/oxc_sourcemap/Cargo.toml
@@ -20,7 +20,13 @@ doctest = false
 
 [dependencies]
 rustc-hash  = { workspace = true }
-rayon       = { workspace = true }
 serde       = { workspace = true, features = ["derive"] }
 serde_json  = { workspace = true }
-base64-simd = "0.8"
+base64-simd = { workspace = true }
+cfg-if      = { workspace = true }
+
+rayon = { workspace = true, optional = true }
+
+[features]
+default = []
+rayon   = ["dep:rayon"]
diff --git a/crates/oxc_sourcemap/src/encode.rs b/crates/oxc_sourcemap/src/encode.rs
index 3ddd29c55ab0d..66c49ceb35dd7 100644
--- a/crates/oxc_sourcemap/src/encode.rs
+++ b/crates/oxc_sourcemap/src/encode.rs
@@ -4,6 +4,7 @@ use crate::error::{Error, Result};
 /// - Quote `source_content` at parallel.
 /// - If you using `ConcatSourceMapBuilder`, serialize `tokens` to vlq `mappings` at parallel.
 use crate::{token::TokenChunk, SourceMap, Token};
+#[cfg(feature = "rayon")]
 use rayon::prelude::*;
 
 // Here using `serde_json::to_string` to serialization `names/source_contents/sources`.
@@ -40,11 +41,21 @@ pub fn encode(sourcemap: &SourceMap) -> Result<String> {
     // Quote `source_content` at parallel.
     if let Some(source_contents) = &sourcemap.source_contents {
         buf.push_str("],\"sourcesContent\":[");
-        let quote_source_contents = source_contents
-            .par_iter()
-            .map(|x| serde_json::to_string(x.as_ref()))
-            .collect::<std::result::Result<Vec<_>, serde_json::Error>>()
-            .map_err(Error::from)?;
+        cfg_if::cfg_if! {
+            if #[cfg(feature = "rayon")] {
+                let quote_source_contents = source_contents
+                    .par_iter()
+                    .map(|x| serde_json::to_string(x.as_ref()))
+                    .collect::<std::result::Result<Vec<_>, serde_json::Error>>()
+                    .map_err(Error::from)?;
+            } else {
+                let quote_source_contents = source_contents
+                    .iter()
+                    .map(|x| serde_json::to_string(x.as_ref()))
+                    .collect::<std::result::Result<Vec<_>, serde_json::Error>>()
+                    .map_err(Error::from)?;
+            }
+        };
         buf.push_str(&quote_source_contents.join(","));
     }
     if let Some(x_google_ignore_list) = &sourcemap.x_google_ignore_list {
@@ -70,10 +81,19 @@ fn serialize_sourcemap_mappings(sm: &SourceMap) -> String {
         },
         |token_chunks| {
             // Serialize `tokens` to vlq `mappings` at parallel.
-            token_chunks
-                .par_iter()
-                .map(|token_chunk| serialize_mappings(&sm.tokens, token_chunk))
-                .collect::<String>()
+            cfg_if::cfg_if! {
+                if #[cfg(feature = "rayon")] {
+                    token_chunks
+                        .par_iter()
+                        .map(|token_chunk| serialize_mappings(&sm.tokens, token_chunk))
+                        .collect::<String>()
+                } else {
+                    token_chunks
+                        .iter()
+                        .map(|token_chunk| serialize_mappings(&sm.tokens, token_chunk))
+                        .collect::<String>()
+                }
+            }
         },
     )
 }
diff --git a/tasks/benchmark/Cargo.toml b/tasks/benchmark/Cargo.toml
index b2c65305f49b3..40534aa23b39b 100644
--- a/tasks/benchmark/Cargo.toml
+++ b/tasks/benchmark/Cargo.toml
@@ -75,7 +75,7 @@ oxc_span         = { workspace = true, optional = true }
 oxc_tasks_common = { workspace = true, optional = true }
 oxc_transformer  = { workspace = true, optional = true }
 oxc_codegen      = { workspace = true, optional = true }
-oxc_sourcemap    = { workspace = true, optional = true }
+oxc_sourcemap    = { workspace = true, features = ["rayon"], optional = true }
 
 criterion  = { package = "criterion2", version = "0.8.0", default-features = false }
 serde      = { workspace = true, optional = true }