[WIP] feat: Add native SourceMap support

core/Cargo.toml

@@ -24,6 +24,7 @@ snapshot_flags_eager_parse = []
 
 [dependencies]
 anyhow.workspace = true
+base64 = "0.22.1"
 bincode.workspace = true
 bit-set.workspace = true
 bit-vec.workspace = true

core/error.rs

@@ -249,7 +249,7 @@ impl JsStackFrame {
     let c = message.get_start_column() as u32 + 1;
     let state = JsRuntime::state_from(scope);
     let mut source_mapper = state.source_mapper.borrow_mut();
-    match source_mapper.apply_source_map(&f, l, c) {
+    match source_mapper.apply_source_map(scope, &f, l, c) {
       SourceMapApplication::Unchanged => Some(JsStackFrame::from_location(
         Some(f),
         Some(l.into()),

core/ops_builtin_v8.rs

@@ -1047,9 +1047,10 @@ fn write_line_and_col_to_ret_buf(
 // 2: mapped line, column, and file name. new line, column, and file name are in
 //    ret_buf. retrieve file name by calling `op_apply_source_map_filename`
 //    immediately after this op returns.
-#[op2(fast)]
+#[op2]
 #[smi]
 pub fn op_apply_source_map(
+  scope: &mut v8::HandleScope,
   state: &JsRuntimeState,
   #[string] file_name: &str,
   #[smi] line_number: u32,
@@ -1060,8 +1061,12 @@ pub fn op_apply_source_map(
     return Err(type_error("retBuf must be 8 bytes"));
   }
   let mut source_mapper = state.source_mapper.borrow_mut();
-  let application =
-    source_mapper.apply_source_map(file_name, line_number, column_number);
+  let application = source_mapper.apply_source_map(
+    scope,
+    file_name,
+    line_number,
+    column_number,
+  );
   match application {
     SourceMapApplication::Unchanged => Ok(0),
     SourceMapApplication::LineAndColumn {
@@ -1137,7 +1142,7 @@ pub fn op_current_user_call_site(
     let application = js_runtime_state
       .source_mapper
       .borrow_mut()
-      .apply_source_map(&file_name, line_number, column_number);
+      .apply_source_map(scope, &file_name, line_number, column_number);
 
     match application {
       SourceMapApplication::Unchanged => {

core/runtime/jsruntime.rs

@@ -922,6 +922,11 @@ impl JsRuntime {
       }
     }
 
+    state_rc
+      .source_mapper
+      .borrow_mut()
+      .set_module_map(module_map.clone());
+
     // SAFETY: Set the module map slot in the context
     unsafe {
       context.set_aligned_pointer_in_embedder_data(

core/source_map.rs

@@ -2,7 +2,11 @@
 
 //! This mod provides functions to remap a `JsError` based on a source map.
 
+use crate::modules::ModuleMap;
 use crate::resolve_url;
+use crate::RequestedModuleType;
+use base64::prelude::BASE64_STANDARD;
+use base64::Engine;
 pub use sourcemap::SourceMap;
 use std::borrow::Cow;
 use std::collections::HashMap;
@@ -62,6 +66,7 @@ pub struct SourceMapper<G: SourceMapGetter> {
   // This is not the right place for this, but it's the easiest way to make
   // op_apply_source_map a fast op. This stashing should happen in #[op2].
   pub(crate) stashed_file_name: Option<String>,
+  pub(crate) maybe_module_map: Option<Rc<ModuleMap>>,
 }
 
 impl<G: SourceMapGetter> SourceMapper<G> {
@@ -72,20 +77,70 @@ impl<G: SourceMapGetter> SourceMapper<G> {
       ext_source_maps: Default::default(),
       getter,
       stashed_file_name: Default::default(),
+      maybe_module_map: None,
     }
   }
 
+  pub fn set_module_map(&mut self, module_map: Rc<ModuleMap>) {
+    assert!(self.maybe_module_map.replace(module_map).is_none());
+  }
+
   pub fn has_user_sources(&self) -> bool {
     self.getter.is_some()
   }
 
+  pub fn apply_source_map_from_module_map(
+    &mut self,
+    scope: &mut v8::HandleScope,
+    file_name: &str,
+    line_number: u32,
+    column_number: u32,
+  ) -> Option<SourceMapApplication> {
+    let module_map = self.maybe_module_map.as_ref()?;
+    let id = module_map.get_id(file_name, RequestedModuleType::None)?;
+
+    let module_handle = module_map.get_handle(id).unwrap();
+    let module = v8::Local::new(scope, module_handle);
+    let unbound_module_script = module.get_unbound_module_script(scope);
+    let maybe_source_mapping_url =
+      unbound_module_script.get_source_mapping_url(scope);
+
+    // TODO(bartlomieju): This should be the last fallback and it's only useful
+    // for eval - probably for `Deno.core.evalContext()`.
+    let maybe_source_url = unbound_module_script
+      .get_source_url(scope)
+      .to_rust_string_lossy(scope);
+    eprintln!("maybe source url {}", maybe_source_url);
+
+    if !maybe_source_mapping_url.is_string() {
+      return None;
+    }
+
+    let source_map_string =
+      maybe_source_mapping_url.to_rust_string_lossy(scope);
+    eprintln!("maybe source mapping url {}", source_map_string);
+
+    let b64 =
+      source_map_string.strip_prefix("data:application/json;base64,")?;
+    let decoded_b64 = BASE64_STANDARD.decode(b64).ok()?;
+    let source_map = SourceMap::from_slice(&decoded_b64).ok()?;
+
+    Some(Self::get_application(
+      &source_map,
+      file_name,
+      line_number,
+      column_number,
+    ))
+  }
+
   /// Apply a source map to the passed location. If there is no source map for
   /// this location, or if the location remains unchanged after mapping, the
   /// changed values are returned.
   ///
   /// Line and column numbers are 1-based.
   pub fn apply_source_map(
     &mut self,
+    scope: &mut v8::HandleScope,
     file_name: &str,
     line_number: u32,
     column_number: u32,
@@ -94,6 +149,17 @@ impl<G: SourceMapGetter> SourceMapper<G> {
     let line_number = line_number - 1;
     let column_number = column_number - 1;
 
+    // TODO(bartlomieju): requires scope and should only be called in a fallback op,
+    // that will access scope if the fast op doesn't return anything.
+    if let Some(app) = self.apply_source_map_from_module_map(
+      scope,
+      file_name,
+      line_number,
+      column_number,
+    ) {
+      return app;
+    }
+
     let getter = self.getter.as_ref();
     let maybe_source_map =
       self.maps.entry(file_name.to_owned()).or_insert_with(|| {
@@ -110,6 +176,15 @@ impl<G: SourceMapGetter> SourceMapper<G> {
       return SourceMapApplication::Unchanged;
     };
 
+    Self::get_application(source_map, file_name, line_number, column_number)
+  }
+
+  fn get_application(
+    source_map: &SourceMap,
+    file_name: &str,
+    line_number: u32,
+    column_number: u32,
+  ) -> SourceMapApplication {
     let Some(token) = source_map.lookup_token(line_number, column_number)
     else {
       return SourceMapApplication::Unchanged;

foo.js

@@ -0,0 +1,6 @@
+"use strict";
+
+throw new Error("Hello world!");
+//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJmaWxlIjoiIiwic291cmNlUm9vdCI6IiIsInNvdXJjZXMiOlsiaHR0cDovL2xvY2FsaG9zdDo0NTQ1L3J1bi9pbmxpbmVfanNfc291cmNlX21hcF8yLnRzIl0sInNvdXJjZXNDb250ZW50IjpbIjErMTtcbmludGVyZmFjZSBUZXN0IHtcbiAgaGVsbG86IHN0cmluZztcbn1cblxudGhyb3cgbmV3IEVycm9yKFwiSGVsbG8gd29ybGQhXCIgYXMgdW5rbm93biBhcyBzdHJpbmcpO1xuIl0sIm5hbWVzIjpbXSwibWFwcGluZ3MiOiI7QUFBQSxDQUFDLEdBQUMsQ0FBQyxDQUFDO0FBS0osTUFBTSxJQUFJLEtBQUssQ0FBQyxjQUErQixDQUFDLENBQUMifQ==
+
+asd;