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trace-mapping.mjs
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Created: Fri, Dec 13, 11:43

trace-mapping.mjs
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	import { encode, decode } from '@jridgewell/sourcemap-codec';
	import resolveUri from '@jridgewell/resolve-uri';

	function resolve(input, base) {
	// The base is always treated as a directory, if it's not empty.
	// https://github.com/mozilla/source-map/blob/8cb3ee57/lib/util.js#L327
	// https://github.com/chromium/chromium/blob/da4adbb3/third_party/blink/renderer/devtools/front_end/sdk/SourceMap.js#L400-L401
	if (base && !base.endsWith('/'))
	base += '/';
	return resolveUri(input, base);
	}

	/**
	* Removes everything after the last "/", but leaves the slash.
	*/
	function stripFilename(path) {
	if (!path)
	return '';
	const index = path.lastIndexOf('/');
	return path.slice(0, index + 1);
	}

	const COLUMN = 0;
	const SOURCES_INDEX = 1;
	const SOURCE_LINE = 2;
	const SOURCE_COLUMN = 3;
	const NAMES_INDEX = 4;
	const REV_GENERATED_LINE = 1;
	const REV_GENERATED_COLUMN = 2;

	function maybeSort(mappings, owned) {
	const unsortedIndex = nextUnsortedSegmentLine(mappings, 0);
	if (unsortedIndex === mappings.length)
	return mappings;
	// If we own the array (meaning we parsed it from JSON), then we're free to directly mutate it. If
	// not, we do not want to modify the consumer's input array.
	if (!owned)
	mappings = mappings.slice();
	for (let i = unsortedIndex; i < mappings.length; i = nextUnsortedSegmentLine(mappings, i + 1)) {
	mappings[i] = sortSegments(mappings[i], owned);
	}
	return mappings;
	}
	function nextUnsortedSegmentLine(mappings, start) {
	for (let i = start; i < mappings.length; i++) {
	if (!isSorted(mappings[i]))
	return i;
	}
	return mappings.length;
	}
	function isSorted(line) {
	for (let j = 1; j < line.length; j++) {
	if (line[j][COLUMN] < line[j - 1][COLUMN]) {
	return false;
	}
	}
	return true;
	}
	function sortSegments(line, owned) {
	if (!owned)
	line = line.slice();
	return line.sort(sortComparator);
	}
	function sortComparator(a, b) {
	return a[COLUMN] - b[COLUMN];
	}

	let found = false;
	/**
	* A binary search implementation that returns the index if a match is found.
	* If no match is found, then the left-index (the index associated with the item that comes just
	* before the desired index) is returned. To maintain proper sort order, a splice would happen at
	* the next index:
	*
	* ```js
	* const array = [1, 3];
	* const needle = 2;
	* const index = binarySearch(array, needle, (item, needle) => item - needle);
	*
	* assert.equal(index, 0);
	* array.splice(index + 1, 0, needle);
	* assert.deepEqual(array, [1, 2, 3]);
	* ```
	*/
	function binarySearch(haystack, needle, low, high) {
	while (low <= high) {
	const mid = low + ((high - low) >> 1);
	const cmp = haystack[mid][COLUMN] - needle;
	if (cmp === 0) {
	found = true;
	return mid;
	}
	if (cmp < 0) {
	low = mid + 1;
	}
	else {
	high = mid - 1;
	}
	}
	found = false;
	return low - 1;
	}
	function upperBound(haystack, needle, index) {
	for (let i = index + 1; i < haystack.length; index = i++) {
	if (haystack[i][COLUMN] !== needle)
	break;
	}
	return index;
	}
	function lowerBound(haystack, needle, index) {
	for (let i = index - 1; i >= 0; index = i--) {
	if (haystack[i][COLUMN] !== needle)
	break;
	}
	return index;
	}
	function memoizedState() {
	return {
	lastKey: -1,
	lastNeedle: -1,
	lastIndex: -1,
	};
	}
	/**
	* This overly complicated beast is just to record the last tested line/column and the resulting
	* index, allowing us to skip a few tests if mappings are monotonically increasing.
	*/
	function memoizedBinarySearch(haystack, needle, state, key) {
	const { lastKey, lastNeedle, lastIndex } = state;
	let low = 0;
	let high = haystack.length - 1;
	if (key === lastKey) {
	if (needle === lastNeedle) {
	found = lastIndex !== -1 && haystack[lastIndex][COLUMN] === needle;
	return lastIndex;
	}
	if (needle >= lastNeedle) {
	// lastIndex may be -1 if the previous needle was not found.
	low = lastIndex === -1 ? 0 : lastIndex;
	}
	else {
	high = lastIndex;
	}
	}
	state.lastKey = key;
	state.lastNeedle = needle;
	return (state.lastIndex = binarySearch(haystack, needle, low, high));
	}

	// Rebuilds the original source files, with mappings that are ordered by source line/column instead
	// of generated line/column.
	function buildBySources(decoded, memos) {
	const sources = memos.map(buildNullArray);
	for (let i = 0; i < decoded.length; i++) {
	const line = decoded[i];
	for (let j = 0; j < line.length; j++) {
	const seg = line[j];
	if (seg.length === 1)
	continue;
	const sourceIndex = seg[SOURCES_INDEX];
	const sourceLine = seg[SOURCE_LINE];
	const sourceColumn = seg[SOURCE_COLUMN];
	const originalSource = sources[sourceIndex];
	const originalLine = (originalSource[sourceLine] \|\| (originalSource[sourceLine] = []));
	const memo = memos[sourceIndex];
	// The binary search either found a match, or it found the left-index just before where the
	// segment should go. Either way, we want to insert after that. And there may be multiple
	// generated segments associated with an original location, so there may need to move several
	// indexes before we find where we need to insert.
	const index = upperBound(originalLine, sourceColumn, memoizedBinarySearch(originalLine, sourceColumn, memo, sourceLine));
	insert(originalLine, (memo.lastIndex = index + 1), [sourceColumn, i, seg[COLUMN]]);
	}
	}
	return sources;
	}
	function insert(array, index, value) {
	for (let i = array.length; i > index; i--) {
	array[i] = array[i - 1];
	}
	array[index] = value;
	}
	// Null arrays allow us to use ordered index keys without actually allocating contiguous memory like
	// a real array. We use a null-prototype object to avoid prototype pollution and deoptimizations.
	// Numeric properties on objects are magically sorted in ascending order by the engine regardless of
	// the insertion order. So, by setting any numeric keys, even out of order, we'll get ascending
	// order when iterating with for-in.
	function buildNullArray() {
	return { __proto__: null };
	}

	const AnyMap = function (map, mapUrl) {
	const parsed = typeof map === 'string' ? JSON.parse(map) : map;
	if (!('sections' in parsed))
	return new TraceMap(parsed, mapUrl);
	const mappings = [];
	const sources = [];
	const sourcesContent = [];
	const names = [];
	recurse(parsed, mapUrl, mappings, sources, sourcesContent, names, 0, 0, Infinity, Infinity);
	const joined = {
	version: 3,
	file: parsed.file,
	names,
	sources,
	sourcesContent,
	mappings,
	};
	return presortedDecodedMap(joined);
	};
	function recurse(input, mapUrl, mappings, sources, sourcesContent, names, lineOffset, columnOffset, stopLine, stopColumn) {
	const { sections } = input;
	for (let i = 0; i < sections.length; i++) {
	const { map, offset } = sections[i];
	let sl = stopLine;
	let sc = stopColumn;
	if (i + 1 < sections.length) {
	const nextOffset = sections[i + 1].offset;
	sl = Math.min(stopLine, lineOffset + nextOffset.line);
	if (sl === stopLine) {
	sc = Math.min(stopColumn, columnOffset + nextOffset.column);
	}
	else if (sl < stopLine) {
	sc = columnOffset + nextOffset.column;
	}
	}
	addSection(map, mapUrl, mappings, sources, sourcesContent, names, lineOffset + offset.line, columnOffset + offset.column, sl, sc);
	}
	}
	function addSection(input, mapUrl, mappings, sources, sourcesContent, names, lineOffset, columnOffset, stopLine, stopColumn) {
	if ('sections' in input)
	return recurse(...arguments);
	const map = new TraceMap(input, mapUrl);
	const sourcesOffset = sources.length;
	const namesOffset = names.length;
	const decoded = decodedMappings(map);
	const { resolvedSources, sourcesContent: contents } = map;
	append(sources, resolvedSources);
	append(names, map.names);
	if (contents)
	append(sourcesContent, contents);
	else
	for (let i = 0; i < resolvedSources.length; i++)
	sourcesContent.push(null);
	for (let i = 0; i < decoded.length; i++) {
	const lineI = lineOffset + i;
	// We can only add so many lines before we step into the range that the next section's map
	// controls. When we get to the last line, then we'll start checking the segments to see if
	// they've crossed into the column range. But it may not have any columns that overstep, so we
	// still need to check that we don't overstep lines, too.
	if (lineI > stopLine)
	return;
	// The out line may already exist in mappings (if we're continuing the line started by a
	// previous section). Or, we may have jumped ahead several lines to start this section.
	const out = getLine(mappings, lineI);
	// On the 0th loop, the section's column offset shifts us forward. On all other lines (since the
	// map can be multiple lines), it doesn't.
	const cOffset = i === 0 ? columnOffset : 0;
	const line = decoded[i];
	for (let j = 0; j < line.length; j++) {
	const seg = line[j];
	const column = cOffset + seg[COLUMN];
	// If this segment steps into the column range that the next section's map controls, we need
	// to stop early.
	if (lineI === stopLine && column >= stopColumn)
	return;
	if (seg.length === 1) {
	out.push([column]);
	continue;
	}
	const sourcesIndex = sourcesOffset + seg[SOURCES_INDEX];
	const sourceLine = seg[SOURCE_LINE];
	const sourceColumn = seg[SOURCE_COLUMN];
	out.push(seg.length === 4
	? [column, sourcesIndex, sourceLine, sourceColumn]
	: [column, sourcesIndex, sourceLine, sourceColumn, namesOffset + seg[NAMES_INDEX]]);
	}
	}
	}
	function append(arr, other) {
	for (let i = 0; i < other.length; i++)
	arr.push(other[i]);
	}
	function getLine(arr, index) {
	for (let i = arr.length; i <= index; i++)
	arr[i] = [];
	return arr[index];
	}

	const LINE_GTR_ZERO = '`line` must be greater than 0 (lines start at line 1)';
	const COL_GTR_EQ_ZERO = '`column` must be greater than or equal to 0 (columns start at column 0)';
	const LEAST_UPPER_BOUND = -1;
	const GREATEST_LOWER_BOUND = 1;
	/**
	* Returns the encoded (VLQ string) form of the SourceMap's mappings field.
	*/
	let encodedMappings;
	/**
	* Returns the decoded (array of lines of segments) form of the SourceMap's mappings field.
	*/
	let decodedMappings;
	/**
	* A low-level API to find the segment associated with a generated line/column (think, from a
	* stack trace). Line and column here are 0-based, unlike `originalPositionFor`.
	*/
	let traceSegment;
	/**
	* A higher-level API to find the source/line/column associated with a generated line/column
	* (think, from a stack trace). Line is 1-based, but column is 0-based, due to legacy behavior in
	* `source-map` library.
	*/
	let originalPositionFor;
	/**
	* Finds the generated line/column position of the provided source/line/column source position.
	*/
	let generatedPositionFor;
	/**
	* Finds all generated line/column positions of the provided source/line/column source position.
	*/
	let allGeneratedPositionsFor;
	/**
	* Iterates each mapping in generated position order.
	*/
	let eachMapping;
	/**
	* Retrieves the source content for a particular source, if its found. Returns null if not.
	*/
	let sourceContentFor;
	/**
	* A helper that skips sorting of the input map's mappings array, which can be expensive for larger
	* maps.
	*/
	let presortedDecodedMap;
	/**
	* Returns a sourcemap object (with decoded mappings) suitable for passing to a library that expects
	* a sourcemap, or to JSON.stringify.
	*/
	let decodedMap;
	/**
	* Returns a sourcemap object (with encoded mappings) suitable for passing to a library that expects
	* a sourcemap, or to JSON.stringify.
	*/
	let encodedMap;
	class TraceMap {
	constructor(map, mapUrl) {
	const isString = typeof map === 'string';
	if (!isString && map._decodedMemo)
	return map;
	const parsed = (isString ? JSON.parse(map) : map);
	const { version, file, names, sourceRoot, sources, sourcesContent } = parsed;
	this.version = version;
	this.file = file;
	this.names = names;
	this.sourceRoot = sourceRoot;
	this.sources = sources;
	this.sourcesContent = sourcesContent;
	const from = resolve(sourceRoot \|\| '', stripFilename(mapUrl));
	this.resolvedSources = sources.map((s) => resolve(s \|\| '', from));
	const { mappings } = parsed;
	if (typeof mappings === 'string') {
	this._encoded = mappings;
	this._decoded = undefined;
	}
	else {
	this._encoded = undefined;
	this._decoded = maybeSort(mappings, isString);
	}
	this._decodedMemo = memoizedState();
	this._bySources = undefined;
	this._bySourceMemos = undefined;
	}
	}
	(() => {
	encodedMappings = (map) => {
	var _a;
	return ((_a = map._encoded) !== null && _a !== void 0 ? _a : (map._encoded = encode(map._decoded)));
	};
	decodedMappings = (map) => {
	return (map._decoded \|\| (map._decoded = decode(map._encoded)));
	};
	traceSegment = (map, line, column) => {
	const decoded = decodedMappings(map);
	// It's common for parent source maps to have pointers to lines that have no
	// mapping (like a "//# sourceMappingURL=") at the end of the child file.
	if (line >= decoded.length)
	return null;
	const segments = decoded[line];
	const index = traceSegmentInternal(segments, map._decodedMemo, line, column, GREATEST_LOWER_BOUND);
	return index === -1 ? null : segments[index];
	};
	originalPositionFor = (map, { line, column, bias }) => {
	line--;
	if (line < 0)
	throw new Error(LINE_GTR_ZERO);
	if (column < 0)
	throw new Error(COL_GTR_EQ_ZERO);
	const decoded = decodedMappings(map);
	// It's common for parent source maps to have pointers to lines that have no
	// mapping (like a "//# sourceMappingURL=") at the end of the child file.
	if (line >= decoded.length)
	return OMapping(null, null, null, null);
	const segments = decoded[line];
	const index = traceSegmentInternal(segments, map._decodedMemo, line, column, bias \|\| GREATEST_LOWER_BOUND);
	if (index === -1)
	return OMapping(null, null, null, null);
	const segment = segments[index];
	if (segment.length === 1)
	return OMapping(null, null, null, null);
	const { names, resolvedSources } = map;
	return OMapping(resolvedSources[segment[SOURCES_INDEX]], segment[SOURCE_LINE] + 1, segment[SOURCE_COLUMN], segment.length === 5 ? names[segment[NAMES_INDEX]] : null);
	};
	allGeneratedPositionsFor = (map, { source, line, column, bias }) => {
	// SourceMapConsumer uses LEAST_UPPER_BOUND for some reason, so we follow suit.
	return generatedPosition(map, source, line, column, bias \|\| LEAST_UPPER_BOUND, true);
	};
	generatedPositionFor = (map, { source, line, column, bias }) => {
	return generatedPosition(map, source, line, column, bias \|\| GREATEST_LOWER_BOUND, false);
	};
	eachMapping = (map, cb) => {
	const decoded = decodedMappings(map);
	const { names, resolvedSources } = map;
	for (let i = 0; i < decoded.length; i++) {
	const line = decoded[i];
	for (let j = 0; j < line.length; j++) {
	const seg = line[j];
	const generatedLine = i + 1;
	const generatedColumn = seg[0];
	let source = null;
	let originalLine = null;
	let originalColumn = null;
	let name = null;
	if (seg.length !== 1) {
	source = resolvedSources[seg[1]];
	originalLine = seg[2] + 1;
	originalColumn = seg[3];
	}
	if (seg.length === 5)
	name = names[seg[4]];
	cb({
	generatedLine,
	generatedColumn,
	source,
	originalLine,
	originalColumn,
	name,
	});
	}
	}
	};
	sourceContentFor = (map, source) => {
	const { sources, resolvedSources, sourcesContent } = map;
	if (sourcesContent == null)
	return null;
	let index = sources.indexOf(source);
	if (index === -1)
	index = resolvedSources.indexOf(source);
	return index === -1 ? null : sourcesContent[index];
	};
	presortedDecodedMap = (map, mapUrl) => {
	const tracer = new TraceMap(clone(map, []), mapUrl);
	tracer._decoded = map.mappings;
	return tracer;
	};
	decodedMap = (map) => {
	return clone(map, decodedMappings(map));
	};
	encodedMap = (map) => {
	return clone(map, encodedMappings(map));
	};
	function generatedPosition(map, source, line, column, bias, all) {
	line--;
	if (line < 0)
	throw new Error(LINE_GTR_ZERO);
	if (column < 0)
	throw new Error(COL_GTR_EQ_ZERO);
	const { sources, resolvedSources } = map;
	let sourceIndex = sources.indexOf(source);
	if (sourceIndex === -1)
	sourceIndex = resolvedSources.indexOf(source);
	if (sourceIndex === -1)
	return all ? [] : GMapping(null, null);
	const generated = (map._bySources \|\| (map._bySources = buildBySources(decodedMappings(map), (map._bySourceMemos = sources.map(memoizedState)))));
	const segments = generated[sourceIndex][line];
	if (segments == null)
	return all ? [] : GMapping(null, null);
	const memo = map._bySourceMemos[sourceIndex];
	if (all)
	return sliceGeneratedPositions(segments, memo, line, column, bias);
	const index = traceSegmentInternal(segments, memo, line, column, bias);
	if (index === -1)
	return GMapping(null, null);
	const segment = segments[index];
	return GMapping(segment[REV_GENERATED_LINE] + 1, segment[REV_GENERATED_COLUMN]);
	}
	})();
	function clone(map, mappings) {
	return {
	version: map.version,
	file: map.file,
	names: map.names,
	sourceRoot: map.sourceRoot,
	sources: map.sources,
	sourcesContent: map.sourcesContent,
	mappings,
	};
	}
	function OMapping(source, line, column, name) {
	return { source, line, column, name };
	}
	function GMapping(line, column) {
	return { line, column };
	}
	function traceSegmentInternal(segments, memo, line, column, bias) {
	let index = memoizedBinarySearch(segments, column, memo, line);
	if (found) {
	index = (bias === LEAST_UPPER_BOUND ? upperBound : lowerBound)(segments, column, index);
	}
	else if (bias === LEAST_UPPER_BOUND)
	index++;
	if (index === -1 \|\| index === segments.length)
	return -1;
	return index;
	}
	function sliceGeneratedPositions(segments, memo, line, column, bias) {
	let min = traceSegmentInternal(segments, memo, line, column, GREATEST_LOWER_BOUND);
	// We ignored the bias when tracing the segment so that we're guarnateed to find the first (in
	// insertion order) segment that matched. Even if we did respect the bias when tracing, we would
	// still need to call `lowerBound()` to find the first segment, which is slower than just looking
	// for the GREATEST_LOWER_BOUND to begin with. The only difference that matters for us is when the
	// binary search didn't match, in which case GREATEST_LOWER_BOUND just needs to increment to
	// match LEAST_UPPER_BOUND.
	if (!found && bias === LEAST_UPPER_BOUND)
	min++;
	if (min === -1 \|\| min === segments.length)
	return [];
	// We may have found the segment that started at an earlier column. If this is the case, then we
	// need to slice all generated segments that match _that_ column, because all such segments span
	// to our desired column.
	const matchedColumn = found ? column : segments[min][COLUMN];
	// The binary search is not guaranteed to find the lower bound when a match wasn't found.
	if (!found)
	min = lowerBound(segments, matchedColumn, min);
	const max = upperBound(segments, matchedColumn, min);
	const result = [];
	for (; min <= max; min++) {
	const segment = segments[min];
	result.push(GMapping(segment[REV_GENERATED_LINE] + 1, segment[REV_GENERATED_COLUMN]));
	}
	return result;
	}

	export { AnyMap, GREATEST_LOWER_BOUND, LEAST_UPPER_BOUND, TraceMap, allGeneratedPositionsFor, decodedMap, decodedMappings, eachMapping, encodedMap, encodedMappings, generatedPositionFor, originalPositionFor, presortedDecodedMap, sourceContentFor, traceSegment };
	//# sourceMappingURL=trace-mapping.mjs.map

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