148 lines
6.1 KiB
JavaScript
148 lines
6.1 KiB
JavaScript
/**
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* Parses a patch into structured data, in the same structure returned by `structuredPatch`.
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*
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* @return a JSON object representation of the a patch, suitable for use with the `applyPatch` method.
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*/
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export function parsePatch(uniDiff) {
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const diffstr = uniDiff.split(/\n/), list = [];
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let i = 0;
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function parseIndex() {
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const index = {};
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list.push(index);
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// Parse diff metadata
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while (i < diffstr.length) {
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const line = diffstr[i];
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// File header found, end parsing diff metadata
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if ((/^(---|\+\+\+|@@)\s/).test(line)) {
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break;
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}
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// Try to parse the line as a diff header, like
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// Index: README.md
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// or
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// diff -r 9117c6561b0b -r 273ce12ad8f1 .hgignore
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// or
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// Index: something with multiple words
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// and extract the filename (or whatever else is used as an index name)
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// from the end (i.e. 'README.md', '.hgignore', or
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// 'something with multiple words' in the examples above).
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//
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// TODO: It seems awkward that we indiscriminately trim off trailing
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// whitespace here. Theoretically, couldn't that be meaningful -
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// e.g. if the patch represents a diff of a file whose name ends
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// with a space? Seems wrong to nuke it.
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// But this behaviour has been around since v2.2.1 in 2015, so if
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// it's going to change, it should be done cautiously and in a new
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// major release, for backwards-compat reasons.
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// -- ExplodingCabbage
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const headerMatch = (/^(?:Index:|diff(?: -r \w+)+)\s+/).exec(line);
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if (headerMatch) {
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index.index = line.substring(headerMatch[0].length).trim();
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}
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i++;
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}
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// Parse file headers if they are defined. Unified diff requires them, but
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// there's no technical issues to have an isolated hunk without file header
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parseFileHeader(index);
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parseFileHeader(index);
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// Parse hunks
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index.hunks = [];
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while (i < diffstr.length) {
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const line = diffstr[i];
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if ((/^(Index:\s|diff\s|---\s|\+\+\+\s|===================================================================)/).test(line)) {
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break;
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}
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else if ((/^@@/).test(line)) {
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index.hunks.push(parseHunk());
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}
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else if (line) {
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throw new Error('Unknown line ' + (i + 1) + ' ' + JSON.stringify(line));
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}
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else {
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i++;
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}
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}
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}
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// Parses the --- and +++ headers, if none are found, no lines
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// are consumed.
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function parseFileHeader(index) {
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const fileHeaderMatch = (/^(---|\+\+\+)\s+/).exec(diffstr[i]);
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if (fileHeaderMatch) {
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const prefix = fileHeaderMatch[1], data = diffstr[i].substring(3).trim().split('\t', 2), header = (data[1] || '').trim();
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let fileName = data[0].replace(/\\\\/g, '\\');
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if (fileName.startsWith('"') && fileName.endsWith('"')) {
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fileName = fileName.substr(1, fileName.length - 2);
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}
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if (prefix === '---') {
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index.oldFileName = fileName;
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index.oldHeader = header;
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}
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else {
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index.newFileName = fileName;
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index.newHeader = header;
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}
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i++;
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}
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}
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// Parses a hunk
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// This assumes that we are at the start of a hunk.
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function parseHunk() {
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var _a;
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const chunkHeaderIndex = i, chunkHeaderLine = diffstr[i++], chunkHeader = chunkHeaderLine.split(/@@ -(\d+)(?:,(\d+))? \+(\d+)(?:,(\d+))? @@/);
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const hunk = {
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oldStart: +chunkHeader[1],
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oldLines: typeof chunkHeader[2] === 'undefined' ? 1 : +chunkHeader[2],
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newStart: +chunkHeader[3],
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newLines: typeof chunkHeader[4] === 'undefined' ? 1 : +chunkHeader[4],
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lines: []
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};
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// Unified Diff Format quirk: If the chunk size is 0,
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// the first number is one lower than one would expect.
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// https://www.artima.com/weblogs/viewpost.jsp?thread=164293
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if (hunk.oldLines === 0) {
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hunk.oldStart += 1;
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}
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if (hunk.newLines === 0) {
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hunk.newStart += 1;
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}
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let addCount = 0, removeCount = 0;
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for (; i < diffstr.length && (removeCount < hunk.oldLines || addCount < hunk.newLines || ((_a = diffstr[i]) === null || _a === void 0 ? void 0 : _a.startsWith('\\'))); i++) {
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const operation = (diffstr[i].length == 0 && i != (diffstr.length - 1)) ? ' ' : diffstr[i][0];
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if (operation === '+' || operation === '-' || operation === ' ' || operation === '\\') {
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hunk.lines.push(diffstr[i]);
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if (operation === '+') {
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addCount++;
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}
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else if (operation === '-') {
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removeCount++;
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}
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else if (operation === ' ') {
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addCount++;
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removeCount++;
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}
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}
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else {
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throw new Error(`Hunk at line ${chunkHeaderIndex + 1} contained invalid line ${diffstr[i]}`);
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}
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}
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// Handle the empty block count case
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if (!addCount && hunk.newLines === 1) {
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hunk.newLines = 0;
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}
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if (!removeCount && hunk.oldLines === 1) {
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hunk.oldLines = 0;
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}
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// Perform sanity checking
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if (addCount !== hunk.newLines) {
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throw new Error('Added line count did not match for hunk at line ' + (chunkHeaderIndex + 1));
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}
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if (removeCount !== hunk.oldLines) {
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throw new Error('Removed line count did not match for hunk at line ' + (chunkHeaderIndex + 1));
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}
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return hunk;
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}
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while (i < diffstr.length) {
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parseIndex();
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}
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return list;
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}
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