diff
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A JavaScript text diff implementation.
358 lines (357 loc) • 15.1 kB
JavaScript
import { diffLines } from '../diff/line.js';
/**
* Returns true if the filename contains characters that require C-style
* quoting (as used by Git and GNU diffutils in diff output).
*/
function needsQuoting(s) {
for (let i = 0; i < s.length; i++) {
if (s[i] < '\x20' || s[i] > '\x7e' || s[i] === '"' || s[i] === '\\') {
return true;
}
}
return false;
}
/**
* C-style quotes a filename, encoding special characters as escape sequences
* and non-ASCII bytes as octal escapes. This is the inverse of
* `parseQuotedFileName` in parse.ts.
*
* Non-ASCII bytes are encoded as UTF-8 before being emitted as octal escapes.
* This matches the behaviour of both Git and GNU diffutils, which always emit
* UTF-8 octal escapes regardless of the underlying filesystem encoding (e.g.
* Git for Windows converts from NTFS's UTF-16 to UTF-8 internally).
*
* If the filename doesn't need quoting, returns it as-is.
*/
function quoteFileNameIfNeeded(s) {
if (!needsQuoting(s)) {
return s;
}
let result = '"';
const bytes = new TextEncoder().encode(s);
let i = 0;
while (i < bytes.length) {
const b = bytes[i];
// See https://en.wikipedia.org/wiki/Escape_sequences_in_C#Escape_sequences
if (b === 0x07) {
result += '\\a';
}
else if (b === 0x08) {
result += '\\b';
}
else if (b === 0x09) {
result += '\\t';
}
else if (b === 0x0a) {
result += '\\n';
}
else if (b === 0x0b) {
result += '\\v';
}
else if (b === 0x0c) {
result += '\\f';
}
else if (b === 0x0d) {
result += '\\r';
}
else if (b === 0x22) {
result += '\\"';
}
else if (b === 0x5c) {
result += '\\\\';
}
else if (b >= 0x20 && b <= 0x7e) {
// Just a printable ASCII character that is neither a double quote nor a
// backslash; no need to escape it.
result += String.fromCharCode(b);
}
else {
// Either part of a non-ASCII character or a control character without a
// special escape sequence; needs escaping as a 3-digit octal escape
result += '\\' + b.toString(8).padStart(3, '0');
}
i++;
}
result += '"';
return result;
}
export const INCLUDE_HEADERS = {
includeIndex: true,
includeUnderline: true,
includeFileHeaders: true
};
export const FILE_HEADERS_ONLY = {
includeIndex: false,
includeUnderline: false,
includeFileHeaders: true
};
export const OMIT_HEADERS = {
includeIndex: false,
includeUnderline: false,
includeFileHeaders: false
};
export function structuredPatch(oldFileName, newFileName, oldStr, newStr, oldHeader, newHeader, options) {
let optionsObj;
if (!options) {
optionsObj = {};
}
else if (typeof options === 'function') {
optionsObj = { callback: options };
}
else {
optionsObj = options;
}
if (typeof optionsObj.context === 'undefined') {
optionsObj.context = 4;
}
// We copy this into its own variable to placate TypeScript, which thinks
// optionsObj.context might be undefined in the callbacks below.
const context = optionsObj.context;
// @ts-expect-error (runtime check for something that is correctly a static type error)
if (optionsObj.newlineIsToken) {
throw new Error('newlineIsToken may not be used with patch-generation functions, only with diffing functions');
}
if (!optionsObj.callback) {
return diffLinesResultToPatch(diffLines(oldStr, newStr, optionsObj));
}
else {
const { callback } = optionsObj;
diffLines(oldStr, newStr, Object.assign(Object.assign({}, optionsObj), { callback: (diff) => {
const patch = diffLinesResultToPatch(diff);
// TypeScript is unhappy without the cast because it does not understand that `patch` may
// be undefined here only if `callback` is StructuredPatchCallbackAbortable:
callback(patch);
} }));
}
function diffLinesResultToPatch(diff) {
// STEP 1: Build up the patch with no "\ No newline at end of file" lines and with the arrays
// of lines containing trailing newline characters. We'll tidy up later...
if (!diff) {
return;
}
diff.push({ value: '', lines: [] }); // Append an empty value to make cleanup easier
function contextLines(lines) {
return lines.map(function (entry) { return ' ' + entry; });
}
const hunks = [];
let oldRangeStart = 0, newRangeStart = 0, curRange = [], oldLine = 1, newLine = 1;
for (let i = 0; i < diff.length; i++) {
const current = diff[i], lines = current.lines || splitLines(current.value);
current.lines = lines;
if (current.added || current.removed) {
// If we have previous context, start with that
if (!oldRangeStart) {
const prev = diff[i - 1];
oldRangeStart = oldLine;
newRangeStart = newLine;
if (prev) {
curRange = context > 0 ? contextLines(prev.lines.slice(-context)) : [];
oldRangeStart -= curRange.length;
newRangeStart -= curRange.length;
}
}
// Output our changes
for (const line of lines) {
curRange.push((current.added ? '+' : '-') + line);
}
// Track the updated file position
if (current.added) {
newLine += lines.length;
}
else {
oldLine += lines.length;
}
}
else {
// Identical context lines. Track line changes
if (oldRangeStart) {
// Close out any changes that have been output (or join overlapping)
if (lines.length <= context * 2 && i < diff.length - 2) {
// Overlapping
for (const line of contextLines(lines)) {
curRange.push(line);
}
}
else {
// end the range and output
const contextSize = Math.min(lines.length, context);
for (const line of contextLines(lines.slice(0, contextSize))) {
curRange.push(line);
}
const hunk = {
oldStart: oldRangeStart,
oldLines: (oldLine - oldRangeStart + contextSize),
newStart: newRangeStart,
newLines: (newLine - newRangeStart + contextSize),
lines: curRange
};
hunks.push(hunk);
oldRangeStart = 0;
newRangeStart = 0;
curRange = [];
}
}
oldLine += lines.length;
newLine += lines.length;
}
}
// Step 2: eliminate the trailing `\n` from each line of each hunk, and, where needed, add
// "\ No newline at end of file".
for (const hunk of hunks) {
for (let i = 0; i < hunk.lines.length; i++) {
if (hunk.lines[i].endsWith('\n')) {
hunk.lines[i] = hunk.lines[i].slice(0, -1);
}
else {
hunk.lines.splice(i + 1, 0, '\\ No newline at end of file');
i++; // Skip the line we just added, then continue iterating
}
}
}
return {
oldFileName: oldFileName, newFileName: newFileName,
oldHeader: oldHeader, newHeader: newHeader,
hunks: hunks
};
}
}
/**
* creates a unified diff patch.
*
* @param patch either a single structured patch object (as returned by `structuredPatch`) or an
* array of them (as returned by `parsePatch`).
* @param headerOptions behaves the same as the `headerOptions` option of `createTwoFilesPatch`.
* Ignored for patches where `isGit` is `true`.
*
* When a patch has `isGit: true`, `formatPatch` output is changed to more closely match Git's
* output: it emits a `diff --git` header, emits Git extended headers as appropriate based on
* properties like `isRename`, `isCreate`, `newMode`, etc, and will omit `---`/`+++` file
* headers for patches with no hunks (e.g. renames without content changes).
*/
export function formatPatch(patch, headerOptions) {
var _a, _b, _c, _d, _e, _f;
if (!headerOptions) {
headerOptions = INCLUDE_HEADERS;
}
if (Array.isArray(patch)) {
if (patch.length > 1 && !headerOptions.includeFileHeaders && !patch.every(p => p.isGit)) {
throw new Error('Cannot omit file headers on a multi-file patch. '
+ '(The result would be unparseable; how would a tool trying to apply '
+ 'the patch know which changes are to which file?)');
}
return patch.map(p => formatPatch(p, headerOptions)).join('\n');
}
const ret = [];
// Git patches have a fixed header format (diff --git, extended headers,
// and ---/+++ when hunks are present), so headerOptions is ignored.
if (patch.isGit) {
headerOptions = INCLUDE_HEADERS;
// Emit Git-style diff --git header and extended headers.
// Git never puts /dev/null in the "diff --git" line; for file
// creations/deletions it uses the real filename on both sides.
if (!patch.oldFileName) {
throw new Error('oldFileName must be specified for Git patches');
}
if (!patch.newFileName) {
throw new Error('newFileName must be specified for Git patches');
}
let gitOldName = patch.oldFileName;
let gitNewName = patch.newFileName;
if (patch.isCreate && gitOldName === '/dev/null') {
gitOldName = gitNewName.replace(/^b\//, 'a/');
}
else if (patch.isDelete && gitNewName === '/dev/null') {
gitNewName = gitOldName.replace(/^a\//, 'b/');
}
ret.push('diff --git ' + quoteFileNameIfNeeded(gitOldName) + ' ' + quoteFileNameIfNeeded(gitNewName));
if (patch.isDelete) {
ret.push('deleted file mode ' + ((_a = patch.oldMode) !== null && _a !== void 0 ? _a : '100644'));
}
if (patch.isCreate) {
ret.push('new file mode ' + ((_b = patch.newMode) !== null && _b !== void 0 ? _b : '100644'));
}
if (patch.oldMode && patch.newMode && !patch.isDelete && !patch.isCreate) {
ret.push('old mode ' + patch.oldMode);
ret.push('new mode ' + patch.newMode);
}
if (patch.isRename) {
ret.push('rename from ' + quoteFileNameIfNeeded(((_c = patch.oldFileName) !== null && _c !== void 0 ? _c : '').replace(/^a\//, '')));
ret.push('rename to ' + quoteFileNameIfNeeded(((_d = patch.newFileName) !== null && _d !== void 0 ? _d : '').replace(/^b\//, '')));
}
if (patch.isCopy) {
ret.push('copy from ' + quoteFileNameIfNeeded(((_e = patch.oldFileName) !== null && _e !== void 0 ? _e : '').replace(/^a\//, '')));
ret.push('copy to ' + quoteFileNameIfNeeded(((_f = patch.newFileName) !== null && _f !== void 0 ? _f : '').replace(/^b\//, '')));
}
}
else {
if (headerOptions.includeIndex && patch.oldFileName == patch.newFileName && patch.oldFileName !== undefined) {
ret.push('Index: ' + patch.oldFileName);
}
if (headerOptions.includeUnderline) {
ret.push('===================================================================');
}
}
// Emit --- / +++ file headers. For Git patches with no hunks (e.g.
// pure renames, mode-only changes), Git omits these, so we do too.
const hasHunks = patch.hunks.length > 0;
if (headerOptions.includeFileHeaders && patch.oldFileName !== undefined && patch.newFileName !== undefined
&& (!patch.isGit || hasHunks)) {
ret.push('--- ' + quoteFileNameIfNeeded(patch.oldFileName) + (patch.oldHeader ? '\t' + patch.oldHeader : ''));
ret.push('+++ ' + quoteFileNameIfNeeded(patch.newFileName) + (patch.newHeader ? '\t' + patch.newHeader : ''));
}
for (let i = 0; i < patch.hunks.length; i++) {
const hunk = patch.hunks[i];
// Unified Diff Format quirk: If the chunk size is 0,
// the first number is one lower than one would expect.
// https://www.artima.com/weblogs/viewpost.jsp?thread=164293
const oldStart = hunk.oldLines === 0 ? hunk.oldStart - 1 : hunk.oldStart;
const newStart = hunk.newLines === 0 ? hunk.newStart - 1 : hunk.newStart;
ret.push('@@ -' + oldStart + ',' + hunk.oldLines
+ ' +' + newStart + ',' + hunk.newLines
+ ' @@');
for (const line of hunk.lines) {
ret.push(line);
}
}
return ret.join('\n') + '\n';
}
export function createTwoFilesPatch(oldFileName, newFileName, oldStr, newStr, oldHeader, newHeader, options) {
if (typeof options === 'function') {
options = { callback: options };
}
if (!(options === null || options === void 0 ? void 0 : options.callback)) {
const patchObj = structuredPatch(oldFileName, newFileName, oldStr, newStr, oldHeader, newHeader, options);
if (!patchObj) {
return;
}
return formatPatch(patchObj, options === null || options === void 0 ? void 0 : options.headerOptions);
}
else {
const { callback } = options;
structuredPatch(oldFileName, newFileName, oldStr, newStr, oldHeader, newHeader, Object.assign(Object.assign({}, options), { callback: patchObj => {
if (!patchObj) {
callback(undefined);
}
else {
callback(formatPatch(patchObj, options.headerOptions));
}
} }));
}
}
export function createPatch(fileName, oldStr, newStr, oldHeader, newHeader, options) {
return createTwoFilesPatch(fileName, fileName, oldStr, newStr, oldHeader, newHeader, options);
}
/**
* Split `text` into an array of lines, including the trailing newline character (where present)
*/
function splitLines(text) {
const hasTrailingNl = text.endsWith('\n');
const result = text.split('\n').map(line => line + '\n');
if (hasTrailingNl) {
result.pop();
}
else {
result.push(result.pop().slice(0, -1));
}
return result;
}