Use inline source maps during bundling

Author: devongovett

src/bundler.rs

@@ -237,7 +237,17 @@ impl<'a, 'o, 's, P: SourceProvider> Bundler<'a, 'o, 's, P> {
       .flat_map(|s| s.stylesheet.as_ref().unwrap().sources.iter().cloned())
       .collect();
 
-    Ok(StyleSheet::new(sources, CssRuleList(rules), self.options.clone()))
+    let mut stylesheet = StyleSheet::new(sources, CssRuleList(rules), self.options.clone());
+
+    stylesheet.source_map_urls = self
+      .stylesheets
+      .get_mut()
+      .unwrap()
+      .iter()
+      .flat_map(|s| s.stylesheet.as_ref().unwrap().source_map_urls.iter().cloned())
+      .collect();
+
+    Ok(stylesheet)
   }
 
   fn find_filename(&self, source_index: u32) -> String {
@@ -329,14 +339,19 @@ impl<'a, 'o, 's, P: SourceProvider> Bundler<'a, 'o, 's, P> {
     opts.filename = filename.to_owned();
     opts.source_index = source_index;
 
+    let mut stylesheet = StyleSheet::parse(code, opts)?;
+
     if let Some(source_map) = &self.source_map {
-      let mut source_map = source_map.lock().unwrap();
-      let source_index = source_map.add_source(filename);
-      let _ = source_map.set_source_content(source_index as usize, code);
+      // Only add source if we don't have an input source map.
+      // If we do, this will be handled by the printer when remapping locations.
+      let sm = stylesheet.source_map_url(0);
+      if sm.is_none() || !sm.unwrap().starts_with("data") {
+        let mut source_map = source_map.lock().unwrap();
+        let source_index = source_map.add_source(filename);
+        let _ = source_map.set_source_content(source_index as usize, code);
+      }
     }
 
-    let mut stylesheet = StyleSheet::parse(code, opts)?;
-
     // Collect and load dependencies for this stylesheet in parallel.
     let dependencies: Result<Vec<u32>, _> = stylesheet
       .rules
@@ -1759,4 +1774,49 @@ mod tests {
       }
     );
   }
+
+  #[test]
+  fn test_source_map() {
+    let source = r#".imported {
+      content: "yay, file support!";
+    }
+    
+    .selector {
+      margin: 1em;
+      background-color: #f60;
+    }
+    
+    .selector .nested {
+      margin: 0.5em;
+    }
+    
+    /*# sourceMappingURL=data:application/json;base64,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 */"#;
+
+    let fs = TestProvider {
+      map: fs! {
+        "/a.css": r#"
+        @import "/b.css";
+        .a { color: red; }
+      "#,
+        "/b.css": source
+      },
+    };
+
+    let mut sm = parcel_sourcemap::SourceMap::new("/");
+    let mut bundler = Bundler::new(&fs, Some(&mut sm), ParserOptions::default());
+    let mut stylesheet = bundler.bundle(Path::new("/a.css")).unwrap();
+    stylesheet.minify(MinifyOptions::default()).unwrap();
+    stylesheet
+      .to_css(PrinterOptions {
+        source_map: Some(&mut sm),
+        minify: true,
+        ..PrinterOptions::default()
+      })
+      .unwrap();
+    let map = sm.to_json(None).unwrap();
+    assert_eq!(
+      map,
+      r#"{"version":3,"sourceRoot":null,"mappings":"ACAA,uCCGA,2CAAA,8BFDQ","sources":["a.css","sass/_demo.scss","stdin"],"sourcesContent":["\n        @import \"/b.css\";\n        .a { color: red; }\n      ",".imported {\n  content: \"yay, file support!\";\n}","@import \"_variables\";\n@import \"_demo\";\n\n.selector {\n  margin: $size;\n  background-color: $brandColor;\n\n  .nested {\n    margin: $size / 2;\n  }\n}"],"names":[]}"#
+    );
+  }
 }

src/lib.rs

@@ -19790,7 +19790,7 @@ mod tests {
     let map = sm.to_json(None).unwrap();
     assert_eq!(
       map,
-      r#"{"version":3,"sourceRoot":null,"mappings":"AEAA,uCFGA,2CAAA","sources":["stdin","sass/_variables.scss","sass/_demo.scss"],"sourcesContent":["@import \"_variables\";\n@import \"_demo\";\n\n.selector {\n  margin: $size;\n  background-color: $brandColor;\n\n  .nested {\n    margin: $size / 2;\n  }\n}","$brandColor: #f60;\n$size: 1em;",".imported {\n  content: \"yay, file support!\";\n}"],"names":[]}"#
+      r#"{"version":3,"sourceRoot":null,"mappings":"AAAA,uCCGA,2CAAA","sources":["sass/_demo.scss","stdin"],"sourcesContent":[".imported {\n  content: \"yay, file support!\";\n}","@import \"_variables\";\n@import \"_demo\";\n\n.selector {\n  margin: $size;\n  background-color: $brandColor;\n\n  .nested {\n    margin: $size / 2;\n  }\n}"],"names":[]}"#
     );
   }
 

src/printer.rs

@@ -61,6 +61,7 @@ pub struct Printer<'a, 'b, 'c, W> {
   pub(crate) sources: Option<&'c Vec<String>>,
   dest: &'a mut W,
   pub(crate) source_map: Option<&'a mut SourceMap>,
+  pub(crate) source_maps: Vec<Option<SourceMap>>,
   pub(crate) loc: Location,
   indent: u8,
   line: u32,
@@ -83,6 +84,7 @@ impl<'a, 'b, 'c, W: std::fmt::Write + Sized> Printer<'a, 'b, 'c, W> {
       sources: None,
       dest,
       source_map: options.source_map,
+      source_maps: Vec::new(),
       loc: Location {
         source_index: 0,
         line: 0,
@@ -205,17 +207,42 @@ impl<'a, 'b, 'c, W: std::fmt::Write + Sized> Printer<'a, 'b, 'c, W> {
   /// Adds a mapping to the source map, if any.
   pub fn add_mapping(&mut self, loc: Location) {
     self.loc = loc;
+
     if let Some(map) = &mut self.source_map {
-      map.add_mapping(
-        self.line,
-        self.col,
-        Some(OriginalLocation {
+    let mut original = OriginalLocation {
           original_line: loc.line,
           original_column: loc.column - 1,
           source: loc.source_index,
           name: None,
-        }),
-      )
+      };
+
+      // Remap using input source map if possible.
+      if let Some(Some(sm)) = self.source_maps.get_mut(loc.source_index as usize) {
+        let mut found_mapping = false;
+        if let Some(mapping) = sm.find_closest_mapping(loc.line, loc.column - 1) {
+          if let Some(orig) = mapping.original {
+            let sources_len = map.get_sources().len();
+            let source_index = map.add_source(sm.get_source(orig.source).unwrap());
+            original.original_line = orig.original_line;
+            original.original_column = orig.original_column;
+            original.source = source_index;
+            original.name = orig.name;
+
+            if map.get_sources().len() > sources_len {
+              let content = sm.get_source_content(orig.source).unwrap().to_owned();
+              let _ = map.set_source_content(source_index as usize, &content);
+            }
+
+            found_mapping = true;
+          }
+          }
+
+        if !found_mapping {
+          return;
+        }
+      }
+
+      map.add_mapping(self.line, self.col, Some(original))
     }
   }
 

src/stylesheet.rs

@@ -66,7 +66,7 @@ pub struct StyleSheet<'i, 'o> {
   /// Sources are referenced by index in the `loc` property of each rule.
   pub sources: Vec<String>,
   /// The source map URL extracted from the original style sheet.
-  pub source_map_url: Option<String>,
+  pub(crate) source_map_urls: Vec<Option<String>>,
   #[cfg_attr(feature = "serde", serde(skip))]
   /// The options the style sheet was originally parsed with.
   options: ParserOptions<'o, 'i>,
@@ -105,7 +105,7 @@ impl<'i, 'o> StyleSheet<'i, 'o> {
   pub fn new(sources: Vec<String>, rules: CssRuleList<'i>, options: ParserOptions<'o, 'i>) -> StyleSheet<'i, 'o> {
     StyleSheet {
       sources,
-      source_map_url: None,
+      source_map_urls: Vec::new(),
       rules,
       options,
     }
@@ -137,16 +137,20 @@ impl<'i, 'o> StyleSheet<'i, 'o> {
 
     Ok(StyleSheet {
       sources: vec![options.filename.clone()],
-      source_map_url: parser.current_source_map_url().map(|s| s.to_owned()),
+      source_map_urls: vec![parser.current_source_map_url().map(|s| s.to_owned())],
       rules: CssRuleList(rules),
       options,
     })
   }
 
-  /// Returns the inline source map associated with the style sheet.
-  pub fn source_map(&self) -> Option<SourceMap> {
-    let source_map_url = self.source_map_url.as_ref()?;
-    SourceMap::from_data_url("/", source_map_url).ok()
+  /// Returns the source map URL for the source at the given index.
+  pub fn source_map_url(&self, source_index: usize) -> Option<&String> {
+    self.source_map_urls.get(source_index)?.as_ref()
+  }
+
+  /// Returns the inline source map associated with the source at the given index.
+  pub fn source_map(&self, source_index: usize) -> Option<SourceMap> {
+    SourceMap::from_data_url("/", self.source_map_url(source_index)?).ok()
   }
 
   /// Minify and transform the style sheet for the provided browser targets.
@@ -200,6 +204,9 @@ impl<'i, 'o> StyleSheet<'i, 'o> {
     let mut printer = Printer::new(&mut dest, options);
 
     printer.sources = Some(&self.sources);
+    if printer.source_map.is_some() {
+      printer.source_maps = self.sources.iter().enumerate().map(|(i, _)| self.source_map(i)).collect();
+    }
 
     if let Some(config) = &self.options.css_modules {
       let mut references = HashMap::new();
@@ -220,12 +227,6 @@ impl<'i, 'o> StyleSheet<'i, 'o> {
       self.rules.to_css(&mut printer)?;
       printer.newline()?;
 
-      if let Some(sm) = printer.source_map {
-        if let Some(mut input_sm) = self.source_map() {
-          let _ = sm.extends(&mut input_sm);
-        }
-      }
-
       Ok(ToCssResult {
         dependencies: printer.dependencies,
         code: dest,