Convert applyPatch to use parsePatch utility

Author: kpdecker

src/patch/apply.js

@@ -1,61 +1,53 @@
-export function applyPatch(oldStr, uniDiff) {
-  let diffstr = uniDiff.split('\n'),
-      hunks = [],
-      i = 0,
-      remEOFNL = false,
-      addEOFNL = false;
+import {parsePatch} from './parse';
 
-  // Skip to the first change hunk
-  while (i < diffstr.length && !(/^@@/.test(diffstr[i]))) {
-    i++;
+export function applyPatch(oldStr, uniDiff) {
+  if (typeof uniDiff === 'string') {
+    uniDiff = parsePatch(uniDiff);
   }
 
-  // Parse the unified diff
-  for (; i < diffstr.length; i++) {
-    if (diffstr[i][0] === '@') {
-      let chnukHeader = diffstr[i].split(/@@ -(\d+),(\d+) \+(\d+),(\d+) @@/);
-      hunks.unshift({
-        start: chnukHeader[3],
-        oldlength: +chnukHeader[2],
-        removed: [],
-        newlength: chnukHeader[4],
-        added: []
-      });
-    } else if (diffstr[i][0] === '+') {
-      hunks[0].added.push(diffstr[i].substr(1));
-    } else if (diffstr[i][0] === '-') {
-      hunks[0].removed.push(diffstr[i].substr(1));
-    } else if (diffstr[i][0] === ' ') {
-      hunks[0].added.push(diffstr[i].substr(1));
-      hunks[0].removed.push(diffstr[i].substr(1));
-    } else if (diffstr[i][0] === '\\') {
-      if (diffstr[i - 1][0] === '+') {
-        remEOFNL = true;
-      } else if (diffstr[i - 1][0] === '-') {
-        addEOFNL = true;
-      }
+  if (Array.isArray(uniDiff)) {
+    if (uniDiff.length > 1) {
+      throw new Error('applyPatch only works with a single input.');
     }
+
+    uniDiff = uniDiff[0];
   }
 
   // Apply the diff to the input
-  let lines = oldStr.split('\n');
-  for (i = hunks.length - 1; i >= 0; i--) {
-    let hunk = hunks[i];
+  let lines = oldStr.split('\n'),
+      hunks = uniDiff.hunks;
+  for (let i = 0; i < hunks.length; i++) {
+    let hunk = hunks[i],
+        toPos = hunk.to.line - 1;
+
     // Sanity check the input string. Bail if we don't match.
-    for (let j = 0; j < hunk.oldlength; j++) {
-      if (lines[hunk.start - 1 + j] !== hunk.removed[j]) {
-        return false;
+    for (let j = 0; j < hunk.lines.length; j++) {
+      let line = hunk.lines[j];
+      if (line.operation === ' ' || line.operation === '-') {
+        // Context sanity check
+        if (lines[toPos] !== line.content) {
+          return false;
+        }
+      }
+
+      if (line.operation === ' ') {
+        toPos++;
+      } else if (line.operation === '-') {
+        lines.splice(toPos, 1);
+      /* istanbul ignore else */
+      } else if (line.operation === '+') {
+        lines.splice(toPos, 0, line.content);
+        toPos++;
       }
     }
-    Array.prototype.splice.apply(lines, [hunk.start - 1, hunk.oldlength].concat(hunk.added));
   }
 
   // Handle EOFNL insertion/removal
-  if (remEOFNL) {
+  if (uniDiff.removeEOFNL) {
     while (!lines[lines.length - 1]) {
       lines.pop();
     }
-  } else if (addEOFNL) {
+  } else if (uniDiff.addEOFNL) {
     lines.push('');
   }
   return lines.join('\n');

test/patch/apply.js

@@ -1,10 +1,54 @@
 import {applyPatch} from '../../lib/patch/apply';
+import {parsePatch} from '../../lib/patch/parse';
 import {createPatch} from '../../lib/patch/create';
 
 import {expect} from 'chai';
 
 describe('patch/apply', function() {
   describe('#applyPatch', function() {
+    it('should accept parsed patches', function() {
+      let patch = parsePatch(
+          'Index: test\n'
+          + '===================================================================\n'
+          + '--- test\theader1\n'
+          + '+++ test\theader2\n'
+          + '@@ -1,3 +1,4 @@\n'
+          + ' line2\n'
+          + ' line3\n'
+          + '+line4\n'
+          + ' line5\n');
+
+      expect(applyPatch(
+          'line2\n'
+          + 'line3\n'
+          + 'line5\n',
+
+          patch))
+        .to.equal(
+          'line2\n'
+          + 'line3\n'
+          + 'line4\n'
+          + 'line5\n');
+
+      expect(applyPatch(
+          'line2\n'
+          + 'line3\n'
+          + 'line5\n',
+
+          patch[0]))
+        .to.equal(
+          'line2\n'
+          + 'line3\n'
+          + 'line4\n'
+          + 'line5\n');
+    });
+
+    it('should error if passed multiple indexes', function() {
+      expect(function() {
+        applyPatch('', [1, 2]);
+      }).to['throw']('applyPatch only works with a single input.');
+    });
+
     it('should apply patches that change the last line', function() {
       expect(applyPatch(
           'line2\n'