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- import { decodedMappings, traceSegment, TraceMap } from '@jridgewell/trace-mapping';
- import { GenMapping, addSegment, setSourceContent, decodedMap, encodedMap } from '@jridgewell/gen-mapping';
- const SOURCELESS_MAPPING = {
- source: null,
- column: null,
- line: null,
- name: null,
- content: null,
- };
- const EMPTY_SOURCES = [];
- function Source(map, sources, source, content) {
- return {
- map,
- sources,
- source,
- content,
- };
- }
- /**
- * MapSource represents a single sourcemap, with the ability to trace mappings into its child nodes
- * (which may themselves be SourceMapTrees).
- */
- function MapSource(map, sources) {
- return Source(map, sources, '', null);
- }
- /**
- * A "leaf" node in the sourcemap tree, representing an original, unmodified source file. Recursive
- * segment tracing ends at the `OriginalSource`.
- */
- function OriginalSource(source, content) {
- return Source(null, EMPTY_SOURCES, source, content);
- }
- /**
- * traceMappings is only called on the root level SourceMapTree, and begins the process of
- * resolving each mapping in terms of the original source files.
- */
- function traceMappings(tree) {
- 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];
- let lastSource = null;
- let lastSourceLine = null;
- let lastSourceColumn = null;
- for (let j = 0; j < segments.length; j++) {
- const segment = segments[j];
- const genCol = segment[0];
- let traced = 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;
- }
- // So we traced a segment down into its original source file. Now push a
- // new segment pointing to this location.
- const { column, line, name, content, source } = traced;
- if (line === lastSourceLine && column === lastSourceColumn && source === lastSource) {
- continue;
- }
- lastSourceLine = line;
- lastSourceColumn = column;
- lastSource = source;
- // Sigh, TypeScript can't figure out source/line/column are either all null, or all non-null...
- addSegment(gen, i, genCol, source, line, column, name);
- if (content != null)
- setSourceContent(gen, source, content);
- }
- }
- return gen;
- }
- /**
- * originalPositionFor is only called on children SourceMapTrees. It recurses down into its own
- * child SourceMapTrees, until we find the original source map.
- */
- function originalPositionFor(source, line, column, name) {
- if (!source.map) {
- return { column, line, name, source: source.source, content: source.content };
- }
- 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);
- }
- function asArray(value) {
- 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.
- */
- function buildSourceMapTree(input, loader) {
- 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, loader, importer, importerDepth) {
- const { resolvedSources, sourcesContent } = map;
- const depth = importerDepth + 1;
- const children = resolvedSources.map((sourceFile, i) => {
- // 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 = {
- importer,
- depth,
- source: sourceFile || '',
- content: 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 } = 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 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;
- return OriginalSource(source, sourceContent);
- });
- return MapSource(map, children);
- }
- /**
- * A SourceMap v3 compatible sourcemap, which only includes fields that were
- * provided to it.
- */
- class SourceMap {
- constructor(map, options) {
- const out = options.decodedMappings ? decodedMap(map) : encodedMap(map);
- this.version = out.version; // SourceMap spec says this should be first.
- this.file = out.file;
- this.mappings = out.mappings;
- this.names = out.names;
- this.sourceRoot = out.sourceRoot;
- this.sources = out.sources;
- if (!options.excludeContent) {
- this.sourcesContent = out.sourcesContent;
- }
- }
- toString() {
- return JSON.stringify(this);
- }
- }
- /**
- * 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.
- */
- function remapping(input, loader, options) {
- const opts = typeof options === 'object' ? options : { excludeContent: !!options, decodedMappings: false };
- const tree = buildSourceMapTree(input, loader);
- return new SourceMap(traceMappings(tree), opts);
- }
- export { remapping as default };
- //# sourceMappingURL=remapping.mjs.map
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