chore: try to using rspack_sources::SourceMap::from_slice

Author: SyMind

Cargo.lock

@@ -83,7 +83,7 @@ regex-syntax        = { version = "0.8.5", default-features = false, features =
 regress             = { version = "0.10.4", default-features = false, features = ["pattern"] }
 ropey               = { version = "1.6.1", default-features = false }
 rspack_resolver     = { features = ["package_json_raw_json_api", "yarn_pnp"], version = "0.6.3", default-features = false }
-rspack_sources      = { git = "https://github.com/SyMind/rspack-sources.git", rev = "1cbefbd08acf0225a9eae9bb4e01084b6886f650", default-features = false }
+rspack_sources      = { git = "https://github.com/SyMind/rspack-sources.git", rev = "d35ec0d64967dd368e87ca860b79496f5f27f1fe", default-features = false }
 rustc-hash          = { version = "2.1.0", default-features = false }
 ryu-js              = { version = "1.0.2", default-features = false }
 scopeguard          = { version = "1.2.0", default-features = false }

Cargo.toml

@@ -1,6 +1,6 @@
 use std::sync::Arc;
 
-use rspack_error::Result;
+use rspack_error::{Result, ToStringResultToRspackResultExt};
 use rspack_sources::{Mapping, OriginalLocation, encode_mappings};
 use rustc_hash::FxHashMap;
 use swc_core::{
@@ -128,42 +128,18 @@ impl JavaScriptCompiler {
     let map = if source_map_config.enable {
       let combined_source_map =
         source_map.build_source_map(&src_map_buf, input_source_map.cloned(), source_map_config);
-
-      let mappings = encode_mappings(combined_source_map.tokens().map(|token| Mapping {
-        generated_line: token.get_dst_line() + 1,
-        generated_column: token.get_dst_col(),
-        original: if token.has_source() {
-          Some(OriginalLocation {
-            source_index: token.get_src_id(),
-            original_line: token.get_src_line() + 1,
-            original_column: token.get_src_col(),
-            name_index: if token.has_name() {
-              Some(token.get_name_id())
-            } else {
-              None
-            },
-          })
-        } else {
-          None
-        },
-      }));
-
-      let mut rspack_source_map = rspack_sources::SourceMap::new(
-        mappings,
-        combined_source_map
-          .sources()
-          .map(ToString::to_string)
-          .collect::<Vec<_>>(),
-        combined_source_map
-          .source_contents()
-          .flatten()
-          .map(ToString::to_string)
-          .collect::<Vec<_>>(),
-        combined_source_map
-          .names()
-          .map(ToString::to_string)
-          .collect::<Vec<_>>(),
-      );
+      let mut output: Vec<u8> = vec![];
+      combined_source_map
+        .to_writer(&mut output)
+        .to_rspack_result()?;
+
+      // Performance optimization: Use rspack_sources::SourceMap::from_slice for zero-copy parsing.
+      // This method provides superior performance and memory efficiency compared to string-based parsing:
+      // - Zero-copy: Parses directly from byte slice without intermediate string allocation
+      // - SIMD acceleration: Leverages simd_json for fast JSON parsing
+      // - Memory efficient: Creates StaticSourceMap variant that borrows from original data
+      let mut rspack_source_map =
+        rspack_sources::SourceMap::from_slice(output).to_rspack_result()?;
       rspack_source_map.set_file(combined_source_map.get_file().map(ToString::to_string));
 
       Some(rspack_source_map)