Website Structure

Frontend-Learner/node_modules/diff/libesm/patch/apply.js

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+import { hasOnlyWinLineEndings, hasOnlyUnixLineEndings } from '../util/string.js';
+import { isWin, isUnix, unixToWin, winToUnix } from './line-endings.js';
+import { parsePatch } from './parse.js';
+import distanceIterator from '../util/distance-iterator.js';
+/**
+ * attempts to apply a unified diff patch.
+ *
+ * Hunks are applied first to last.
+ * `applyPatch` first tries to apply the first hunk at the line number specified in the hunk header, and with all context lines matching exactly.
+ * If that fails, it tries scanning backwards and forwards, one line at a time, to find a place to apply the hunk where the context lines match exactly.
+ * If that still fails, and `fuzzFactor` is greater than zero, it increments the maximum number of mismatches (missing, extra, or changed context lines) that there can be between the hunk context and a region where we are trying to apply the patch such that the hunk will still be considered to match.
+ * Regardless of `fuzzFactor`, lines to be deleted in the hunk *must* be present for a hunk to match, and the context lines *immediately* before and after an insertion must match exactly.
+ *
+ * Once a hunk is successfully fitted, the process begins again with the next hunk.
+ * Regardless of `fuzzFactor`, later hunks must be applied later in the file than earlier hunks.
+ *
+ * If a hunk cannot be successfully fitted *anywhere* with fewer than `fuzzFactor` mismatches, `applyPatch` fails and returns `false`.
+ *
+ * If a hunk is successfully fitted but not at the line number specified by the hunk header, all subsequent hunks have their target line number adjusted accordingly.
+ * (e.g. if the first hunk is applied 10 lines below where the hunk header said it should fit, `applyPatch` will *start* looking for somewhere to apply the second hunk 10 lines below where its hunk header says it goes.)
+ *
+ * If the patch was applied successfully, returns a string containing the patched text.
+ * If the patch could not be applied (because some hunks in the patch couldn't be fitted to the text in `source`), `applyPatch` returns false.
+ *
+ * @param patch a string diff or the output from the `parsePatch` or `structuredPatch` methods.
+ */
+export function applyPatch(source, patch, options = {}) {
+    let patches;
+    if (typeof patch === 'string') {
+        patches = parsePatch(patch);
+    }
+    else if (Array.isArray(patch)) {
+        patches = patch;
+    }
+    else {
+        patches = [patch];
+    }
+    if (patches.length > 1) {
+        throw new Error('applyPatch only works with a single input.');
+    }
+    return applyStructuredPatch(source, patches[0], options);
+}
+function applyStructuredPatch(source, patch, options = {}) {
+    if (options.autoConvertLineEndings || options.autoConvertLineEndings == null) {
+        if (hasOnlyWinLineEndings(source) && isUnix(patch)) {
+            patch = unixToWin(patch);
+        }
+        else if (hasOnlyUnixLineEndings(source) && isWin(patch)) {
+            patch = winToUnix(patch);
+        }
+    }
+    // Apply the diff to the input
+    const lines = source.split('\n'), hunks = patch.hunks, compareLine = options.compareLine || ((lineNumber, line, operation, patchContent) => line === patchContent), fuzzFactor = options.fuzzFactor || 0;
+    let minLine = 0;
+    if (fuzzFactor < 0 || !Number.isInteger(fuzzFactor)) {
+        throw new Error('fuzzFactor must be a non-negative integer');
+    }
+    // Special case for empty patch.
+    if (!hunks.length) {
+        return source;
+    }
+    // Before anything else, handle EOFNL insertion/removal. If the patch tells us to make a change
+    // to the EOFNL that is redundant/impossible - i.e. to remove a newline that's not there, or add a
+    // newline that already exists - then we either return false and fail to apply the patch (if
+    // fuzzFactor is 0) or simply ignore the problem and do nothing (if fuzzFactor is >0).
+    // If we do need to remove/add a newline at EOF, this will always be in the final hunk:
+    let prevLine = '', removeEOFNL = false, addEOFNL = false;
+    for (let i = 0; i < hunks[hunks.length - 1].lines.length; i++) {
+        const line = hunks[hunks.length - 1].lines[i];
+        if (line[0] == '\\') {
+            if (prevLine[0] == '+') {
+                removeEOFNL = true;
+            }
+            else if (prevLine[0] == '-') {
+                addEOFNL = true;
+            }
+        }
+        prevLine = line;
+    }
+    if (removeEOFNL) {
+        if (addEOFNL) {
+            // This means the final line gets changed but doesn't have a trailing newline in either the
+            // original or patched version. In that case, we do nothing if fuzzFactor > 0, and if
+            // fuzzFactor is 0, we simply validate that the source file has no trailing newline.
+            if (!fuzzFactor && lines[lines.length - 1] == '') {
+                return false;
+            }
+        }
+        else if (lines[lines.length - 1] == '') {
+            lines.pop();
+        }
+        else if (!fuzzFactor) {
+            return false;
+        }
+    }
+    else if (addEOFNL) {
+        if (lines[lines.length - 1] != '') {
+            lines.push('');
+        }
+        else if (!fuzzFactor) {
+            return false;
+        }
+    }
+    /**
+     * Checks if the hunk can be made to fit at the provided location with at most `maxErrors`
+     * insertions, substitutions, or deletions, while ensuring also that:
+     * - lines deleted in the hunk match exactly, and
+     * - wherever an insertion operation or block of insertion operations appears in the hunk, the
+     *   immediately preceding and following lines of context match exactly
+     *
+     * `toPos` should be set such that lines[toPos] is meant to match hunkLines[0].
+     *
+     * If the hunk can be applied, returns an object with properties `oldLineLastI` and
+     * `replacementLines`. Otherwise, returns null.
+     */
+    function applyHunk(hunkLines, toPos, maxErrors, hunkLinesI = 0, lastContextLineMatched = true, patchedLines = [], patchedLinesLength = 0) {
+        let nConsecutiveOldContextLines = 0;
+        let nextContextLineMustMatch = false;
+        for (; hunkLinesI < hunkLines.length; hunkLinesI++) {
+            const hunkLine = hunkLines[hunkLinesI], operation = (hunkLine.length > 0 ? hunkLine[0] : ' '), content = (hunkLine.length > 0 ? hunkLine.substr(1) : hunkLine);
+            if (operation === '-') {
+                if (compareLine(toPos + 1, lines[toPos], operation, content)) {
+                    toPos++;
+                    nConsecutiveOldContextLines = 0;
+                }
+                else {
+                    if (!maxErrors || lines[toPos] == null) {
+                        return null;
+                    }
+                    patchedLines[patchedLinesLength] = lines[toPos];
+                    return applyHunk(hunkLines, toPos + 1, maxErrors - 1, hunkLinesI, false, patchedLines, patchedLinesLength + 1);
+                }
+            }
+            if (operation === '+') {
+                if (!lastContextLineMatched) {
+                    return null;
+                }
+                patchedLines[patchedLinesLength] = content;
+                patchedLinesLength++;
+                nConsecutiveOldContextLines = 0;
+                nextContextLineMustMatch = true;
+            }
+            if (operation === ' ') {
+                nConsecutiveOldContextLines++;
+                patchedLines[patchedLinesLength] = lines[toPos];
+                if (compareLine(toPos + 1, lines[toPos], operation, content)) {
+                    patchedLinesLength++;
+                    lastContextLineMatched = true;
+                    nextContextLineMustMatch = false;
+                    toPos++;
+                }
+                else {
+                    if (nextContextLineMustMatch || !maxErrors) {
+                        return null;
+                    }
+                    // Consider 3 possibilities in sequence:
+                    // 1. lines contains a *substitution* not included in the patch context, or
+                    // 2. lines contains an *insertion* not included in the patch context, or
+                    // 3. lines contains a *deletion* not included in the patch context
+                    // The first two options are of course only possible if the line from lines is non-null -
+                    // i.e. only option 3 is possible if we've overrun the end of the old file.
+                    return (lines[toPos] && (applyHunk(hunkLines, toPos + 1, maxErrors - 1, hunkLinesI + 1, false, patchedLines, patchedLinesLength + 1) || applyHunk(hunkLines, toPos + 1, maxErrors - 1, hunkLinesI, false, patchedLines, patchedLinesLength + 1)) || applyHunk(hunkLines, toPos, maxErrors - 1, hunkLinesI + 1, false, patchedLines, patchedLinesLength));
+                }
+            }
+        }
+        // Before returning, trim any unmodified context lines off the end of patchedLines and reduce
+        // toPos (and thus oldLineLastI) accordingly. This allows later hunks to be applied to a region
+        // that starts in this hunk's trailing context.
+        patchedLinesLength -= nConsecutiveOldContextLines;
+        toPos -= nConsecutiveOldContextLines;
+        patchedLines.length = patchedLinesLength;
+        return {
+            patchedLines,
+            oldLineLastI: toPos - 1
+        };
+    }
+    const resultLines = [];
+    // Search best fit offsets for each hunk based on the previous ones
+    let prevHunkOffset = 0;
+    for (let i = 0; i < hunks.length; i++) {
+        const hunk = hunks[i];
+        let hunkResult;
+        const maxLine = lines.length - hunk.oldLines + fuzzFactor;
+        let toPos;
+        for (let maxErrors = 0; maxErrors <= fuzzFactor; maxErrors++) {
+            toPos = hunk.oldStart + prevHunkOffset - 1;
+            const iterator = distanceIterator(toPos, minLine, maxLine);
+            for (; toPos !== undefined; toPos = iterator()) {
+                hunkResult = applyHunk(hunk.lines, toPos, maxErrors);
+                if (hunkResult) {
+                    break;
+                }
+            }
+            if (hunkResult) {
+                break;
+            }
+        }
+        if (!hunkResult) {
+            return false;
+        }
+        // Copy everything from the end of where we applied the last hunk to the start of this hunk
+        for (let i = minLine; i < toPos; i++) {
+            resultLines.push(lines[i]);
+        }
+        // Add the lines produced by applying the hunk:
+        for (let i = 0; i < hunkResult.patchedLines.length; i++) {
+            const line = hunkResult.patchedLines[i];
+            resultLines.push(line);
+        }
+        // Set lower text limit to end of the current hunk, so next ones don't try
+        // to fit over already patched text
+        minLine = hunkResult.oldLineLastI + 1;
+        // Note the offset between where the patch said the hunk should've applied and where we
+        // applied it, so we can adjust future hunks accordingly:
+        prevHunkOffset = toPos + 1 - hunk.oldStart;
+    }
+    // Copy over the rest of the lines from the old text
+    for (let i = minLine; i < lines.length; i++) {
+        resultLines.push(lines[i]);
+    }
+    return resultLines.join('\n');
+}
+/**
+ * applies one or more patches.
+ *
+ * `patch` may be either an array of structured patch objects, or a string representing a patch in unified diff format (which may patch one or more files).
+ *
+ * This method will iterate over the contents of the patch and apply to data provided through callbacks. The general flow for each patch index is:
+ *
+ * - `options.loadFile(index, callback)` is called. The caller should then load the contents of the file and then pass that to the `callback(err, data)` callback. Passing an `err` will terminate further patch execution.
+ * - `options.patched(index, content, callback)` is called once the patch has been applied. `content` will be the return value from `applyPatch`. When it's ready, the caller should call `callback(err)` callback. Passing an `err` will terminate further patch execution.
+ *
+ * Once all patches have been applied or an error occurs, the `options.complete(err)` callback is made.
+ */
+export function applyPatches(uniDiff, options) {
+    const spDiff = typeof uniDiff === 'string' ? parsePatch(uniDiff) : uniDiff;
+    let currentIndex = 0;
+    function processIndex() {
+        const index = spDiff[currentIndex++];
+        if (!index) {
+            return options.complete();
+        }
+        options.loadFile(index, function (err, data) {
+            if (err) {
+                return options.complete(err);
+            }
+            const updatedContent = applyPatch(data, index, options);
+            options.patched(index, updatedContent, function (err) {
+                if (err) {
+                    return options.complete(err);
+                }
+                processIndex();
+            });
+        });
+    }
+    processIndex();
+}