update

node_modules/@jridgewell/remapping/src/source-map-tree.ts

@@ -0,0 +1,172 @@
+import { GenMapping, maybeAddSegment, setIgnore, setSourceContent } from '@jridgewell/gen-mapping';
+import { traceSegment, decodedMappings } from '@jridgewell/trace-mapping';
+
+import type { TraceMap } from '@jridgewell/trace-mapping';
+
+export type SourceMapSegmentObject = {
+  column: number;
+  line: number;
+  name: string;
+  source: string;
+  content: string | null;
+  ignore: boolean;
+};
+
+export type OriginalSource = {
+  map: null;
+  sources: Sources[];
+  source: string;
+  content: string | null;
+  ignore: boolean;
+};
+
+export type MapSource = {
+  map: TraceMap;
+  sources: Sources[];
+  source: string;
+  content: null;
+  ignore: false;
+};
+
+export type Sources = OriginalSource | MapSource;
+
+const SOURCELESS_MAPPING = /* #__PURE__ */ SegmentObject('', -1, -1, '', null, false);
+const EMPTY_SOURCES: Sources[] = [];
+
+function SegmentObject(
+  source: string,
+  line: number,
+  column: number,
+  name: string,
+  content: string | null,
+  ignore: boolean,
+): SourceMapSegmentObject {
+  return { source, line, column, name, content, ignore };
+}
+
+function Source(
+  map: TraceMap,
+  sources: Sources[],
+  source: '',
+  content: null,
+  ignore: false,
+): MapSource;
+function Source(
+  map: null,
+  sources: Sources[],
+  source: string,
+  content: string | null,
+  ignore: boolean,
+): OriginalSource;
+function Source(
+  map: TraceMap | null,
+  sources: Sources[],
+  source: string | '',
+  content: string | null,
+  ignore: boolean,
+): Sources {
+  return {
+    map,
+    sources,
+    source,
+    content,
+    ignore,
+  } as any;
+}
+
+/**
+ * MapSource represents a single sourcemap, with the ability to trace mappings into its child nodes
+ * (which may themselves be SourceMapTrees).
+ */
+export function MapSource(map: TraceMap, sources: Sources[]): MapSource {
+  return Source(map, sources, '', null, false);
+}
+
+/**
+ * A "leaf" node in the sourcemap tree, representing an original, unmodified source file. Recursive
+ * segment tracing ends at the `OriginalSource`.
+ */
+export function OriginalSource(
+  source: string,
+  content: string | null,
+  ignore: boolean,
+): OriginalSource {
+  return Source(null, EMPTY_SOURCES, source, content, ignore);
+}
+
+/**
+ * traceMappings is only called on the root level SourceMapTree, and begins the process of
+ * resolving each mapping in terms of the original source files.
+ */
+export function traceMappings(tree: MapSource): GenMapping {
+  // TODO: Eventually support sourceRoot, which has to be removed because the sources are already
+  // fully resolved. We'll need to make sources relative to the sourceRoot before adding them.
+  const gen = new GenMapping({ file: tree.map.file });
+  const { sources: rootSources, map } = tree;
+  const rootNames = map.names;
+  const rootMappings = decodedMappings(map);
+
+  for (let i = 0; i < rootMappings.length; i++) {
+    const segments = rootMappings[i];
+
+    for (let j = 0; j < segments.length; j++) {
+      const segment = segments[j];
+      const genCol = segment[0];
+      let traced: SourceMapSegmentObject | null = SOURCELESS_MAPPING;
+
+      // 1-length segments only move the current generated column, there's no source information
+      // to gather from it.
+      if (segment.length !== 1) {
+        const source = rootSources[segment[1]];
+        traced = originalPositionFor(
+          source,
+          segment[2],
+          segment[3],
+          segment.length === 5 ? rootNames[segment[4]] : '',
+        );
+
+        // If the trace is invalid, then the trace ran into a sourcemap that doesn't contain a
+        // respective segment into an original source.
+        if (traced == null) continue;
+      }
+
+      const { column, line, name, content, source, ignore } = traced;
+
+      maybeAddSegment(gen, i, genCol, source, line, column, name);
+      if (source && content != null) setSourceContent(gen, source, content);
+      if (ignore) setIgnore(gen, source, true);
+    }
+  }
+
+  return gen;
+}
+
+/**
+ * originalPositionFor is only called on children SourceMapTrees. It recurses down into its own
+ * child SourceMapTrees, until we find the original source map.
+ */
+export function originalPositionFor(
+  source: Sources,
+  line: number,
+  column: number,
+  name: string,
+): SourceMapSegmentObject | null {
+  if (!source.map) {
+    return SegmentObject(source.source, line, column, name, source.content, source.ignore);
+  }
+
+  const segment = traceSegment(source.map, line, column);
+
+  // If we couldn't find a segment, then this doesn't exist in the sourcemap.
+  if (segment == null) return null;
+  // 1-length segments only move the current generated column, there's no source information
+  // to gather from it.
+  if (segment.length === 1) return SOURCELESS_MAPPING;
+
+  return originalPositionFor(
+    source.sources[segment[1]],
+    segment[2],
+    segment[3],
+    segment.length === 5 ? source.map.names[segment[4]] : name,
+  );
+}