LiveEdit: calculate a real script difference

test/mjsunit/debug-liveedit-diff.js

Index: test/mjsunit/debug-liveedit-diff.js
diff --git a/test/mjsunit/debug-liveedit-diff.js b/test/mjsunit/debug-liveedit-diff.js
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index 0000000000000000000000000000000000000000..402bf14136a3169bf2760414180e632c9f260d24
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+++ b/test/mjsunit/debug-liveedit-diff.js
@@ -0,0 +1,100 @@
+// Copyright 2010 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Flags: --expose-debug-as debug
+// Get the Debug object exposed from the debug context global object.
+
+Debug = debug.Debug
+
+function CheckCompareOneWay(s1, s2) {
+  var diff_array = Debug.LiveEdit.CompareStringsLinewise(s1, s2);
+
+  var pos1 = 0;
+  var pos2 = 0;
+  print("Compare:");
+  for (var i = 0; i < diff_array.length; i += 3) {
+    var similar_length = diff_array[i] - pos1;
+    assertEquals(s1.substring(pos1, pos1 + similar_length),
+                 s2.substring(pos2, pos2 + similar_length));
+
+    print(s1.substring(pos1, pos1 + similar_length));
+    pos1 += similar_length;
+    pos2 += similar_length;
+    print("<<< " + pos1 + " " + diff_array[i + 1]);
+    print(s1.substring(pos1, pos1 + diff_array[i + 1]));
+    print("===");
+    print(s2.substring(pos2, pos2 + diff_array[i + 2]));
+    print(">>> " + pos2 + " " + diff_array[i + 2]);
+    pos1 += diff_array[i + 1];
+    pos2 += diff_array[i + 2];
+  }
+  {
+    // After last change
+    var similar_length = s1.length - pos1;
+    assertEquals(similar_length, s2.length - pos2);
+    assertEquals(s1.substring(pos1, pos1 + similar_length),
+                 s2.substring(pos2, pos2 + similar_length));
+
+    print(s1.substring(pos1, pos1 + similar_length));
+  }
+  print("");
+}
+
+function CheckCompare(s1, s2) {
+  CheckCompareOneWay(s1, s2);
+  CheckCompareOneWay(s2, s1);
+}
+
+CheckCompare("", "");
+
+CheckCompare("a", "b");
+
+CheckCompare(
+    "yesterday\nall\nmy\ntroubles\nseemed\nso\nfar\naway",
+    "yesterday\nall\nmy\ntroubles\nseem\nso\nfar\naway"
+);
+
+CheckCompare(
+    "yesterday\nall\nmy\ntroubles\nseemed\nso\nfar\naway",
+    "\nall\nmy\ntroubles\nseemed\nso\nfar\naway"
+);
+
+CheckCompare(
+    "yesterday\nall\nmy\ntroubles\nseemed\nso\nfar\naway",
+    "all\nmy\ntroubles\nseemed\nso\nfar\naway"
+);
+
+CheckCompare(
+    "yesterday\nall\nmy\ntroubles\nseemed\nso\nfar\naway",
+    "yesterday\nall\nmy\ntroubles\nseemed\nso\nfar\naway\n"
+);
+
+CheckCompare(
+    "yesterday\nall\nmy\ntroubles\nseemed\nso\nfar\naway",
+    "yesterday\nall\nmy\ntroubles\nseemed\nso\n"
+);
+