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

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+import { TraceMap } from '@jridgewell/trace-mapping';
+
+import { OriginalSource, MapSource } from './source-map-tree';
+
+import type { Sources, MapSource as MapSourceType } from './source-map-tree';
+import type { SourceMapInput, SourceMapLoader, LoaderContext } from './types';
+
+function asArray<T>(value: T | T[]): T[] {
+  if (Array.isArray(value)) return value;
+  return [value];
+}
+
+/**
+ * Recursively builds a tree structure out of sourcemap files, with each node
+ * being either an `OriginalSource` "leaf" or a `SourceMapTree` composed of
+ * `OriginalSource`s and `SourceMapTree`s.
+ *
+ * Every sourcemap is composed of a collection of source files and mappings
+ * into locations of those source files. When we generate a `SourceMapTree` for
+ * the sourcemap, we attempt to load each source file's own sourcemap. If it
+ * does not have an associated sourcemap, it is considered an original,
+ * unmodified source file.
+ */
+export default function buildSourceMapTree(
+  input: SourceMapInput | SourceMapInput[],
+  loader: SourceMapLoader,
+): MapSourceType {
+  const maps = asArray(input).map((m) => new TraceMap(m, ''));
+  const map = maps.pop()!;
+
+  for (let i = 0; i < maps.length; i++) {
+    if (maps[i].sources.length > 1) {
+      throw new Error(
+        `Transformation map ${i} must have exactly one source file.\n` +
+          'Did you specify these with the most recent transformation maps first?',
+      );
+    }
+  }
+
+  let tree = build(map, loader, '', 0);
+  for (let i = maps.length - 1; i >= 0; i--) {
+    tree = MapSource(maps[i], [tree]);
+  }
+  return tree;
+}
+
+function build(
+  map: TraceMap,
+  loader: SourceMapLoader,
+  importer: string,
+  importerDepth: number,
+): MapSourceType {
+  const { resolvedSources, sourcesContent, ignoreList } = map;
+
+  const depth = importerDepth + 1;
+  const children = resolvedSources.map((sourceFile: string | null, i: number): Sources => {
+    // The loading context gives the loader more information about why this file is being loaded
+    // (eg, from which importer). It also allows the loader to override the location of the loaded
+    // sourcemap/original source, or to override the content in the sourcesContent field if it's
+    // an unmodified source file.
+    const ctx: LoaderContext = {
+      importer,
+      depth,
+      source: sourceFile || '',
+      content: undefined,
+      ignore: undefined,
+    };
+
+    // Use the provided loader callback to retrieve the file's sourcemap.
+    // TODO: We should eventually support async loading of sourcemap files.
+    const sourceMap = loader(ctx.source, ctx);
+
+    const { source, content, ignore } = ctx;
+
+    // If there is a sourcemap, then we need to recurse into it to load its source files.
+    if (sourceMap) return build(new TraceMap(sourceMap, source), loader, source, depth);
+
+    // Else, it's an unmodified source file.
+    // The contents of this unmodified source file can be overridden via the loader context,
+    // allowing it to be explicitly null or a string. If it remains undefined, we fall back to
+    // the importing sourcemap's `sourcesContent` field.
+    const sourceContent =
+      content !== undefined ? content : sourcesContent ? sourcesContent[i] : null;
+    const ignored = ignore !== undefined ? ignore : ignoreList ? ignoreList.includes(i) : false;
+    return OriginalSource(source, sourceContent, ignored);
+  });
+
+  return MapSource(map, children);
+}

node_modules/@jridgewell/remapping/src/remapping.ts

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+import buildSourceMapTree from './build-source-map-tree';
+import { traceMappings } from './source-map-tree';
+import SourceMap from './source-map';
+
+import type { SourceMapInput, SourceMapLoader, Options } from './types';
+export type {
+  SourceMapSegment,
+  EncodedSourceMap,
+  EncodedSourceMap as RawSourceMap,
+  DecodedSourceMap,
+  SourceMapInput,
+  SourceMapLoader,
+  LoaderContext,
+  Options,
+} from './types';
+export type { SourceMap };
+
+/**
+ * Traces through all the mappings in the root sourcemap, through the sources
+ * (and their sourcemaps), all the way back to the original source location.
+ *
+ * `loader` will be called every time we encounter a source file. If it returns
+ * a sourcemap, we will recurse into that sourcemap to continue the trace. If
+ * it returns a falsey value, that source file is treated as an original,
+ * unmodified source file.
+ *
+ * Pass `excludeContent` to exclude any self-containing source file content
+ * from the output sourcemap.
+ *
+ * Pass `decodedMappings` to receive a SourceMap with decoded (instead of
+ * VLQ encoded) mappings.
+ */
+export default function remapping(
+  input: SourceMapInput | SourceMapInput[],
+  loader: SourceMapLoader,
+  options?: boolean | Options,
+): SourceMap {
+  const opts =
+    typeof options === 'object' ? options : { excludeContent: !!options, decodedMappings: false };
+  const tree = buildSourceMapTree(input, loader);
+  return new SourceMap(traceMappings(tree), opts);
+}

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

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+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,
+  );
+}

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

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+import { toDecodedMap, toEncodedMap } from '@jridgewell/gen-mapping';
+
+import type { GenMapping } from '@jridgewell/gen-mapping';
+import type { DecodedSourceMap, EncodedSourceMap, Options } from './types';
+
+/**
+ * A SourceMap v3 compatible sourcemap, which only includes fields that were
+ * provided to it.
+ */
+export default class SourceMap {
+  declare file?: string | null;
+  declare mappings: EncodedSourceMap['mappings'] | DecodedSourceMap['mappings'];
+  declare sourceRoot?: string;
+  declare names: string[];
+  declare sources: (string | null)[];
+  declare sourcesContent?: (string | null)[];
+  declare version: 3;
+  declare ignoreList: number[] | undefined;
+
+  constructor(map: GenMapping, options: Options) {
+    const out = options.decodedMappings ? toDecodedMap(map) : toEncodedMap(map);
+    this.version = out.version; // SourceMap spec says this should be first.
+    this.file = out.file;
+    this.mappings = out.mappings as SourceMap['mappings'];
+    this.names = out.names as SourceMap['names'];
+    this.ignoreList = out.ignoreList as SourceMap['ignoreList'];
+    this.sourceRoot = out.sourceRoot;
+
+    this.sources = out.sources as SourceMap['sources'];
+    if (!options.excludeContent) {
+      this.sourcesContent = out.sourcesContent as SourceMap['sourcesContent'];
+    }
+  }
+
+  toString(): string {
+    return JSON.stringify(this);
+  }
+}

node_modules/@jridgewell/remapping/src/types.ts

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+import type { SourceMapInput } from '@jridgewell/trace-mapping';
+
+export type {
+  SourceMapSegment,
+  DecodedSourceMap,
+  EncodedSourceMap,
+} from '@jridgewell/trace-mapping';
+
+export type { SourceMapInput };
+
+export type LoaderContext = {
+  readonly importer: string;
+  readonly depth: number;
+  source: string;
+  content: string | null | undefined;
+  ignore: boolean | undefined;
+};
+
+export type SourceMapLoader = (
+  file: string,
+  ctx: LoaderContext,
+) => SourceMapInput | null | undefined | void;
+
+export type Options = {
+  excludeContent?: boolean;
+  decodedMappings?: boolean;
+};