LiveEdit: calculate a real script difference

test/cctest/test-liveedit.cc

+// Copyright 2007-2008 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.
+
+#include <stdlib.h>
+
+#include "v8.h"
+
+#include "liveedit.h"
+#include "cctest.h"
+
+
+using namespace v8::internal;
+
+// Anonymous namespace.
+namespace {
+
+class StringCompareInput : public Compare::Input {
+ public:
+  StringCompareInput(const char* s1, const char* s2) : s1_(s1), s2_(s2) {
+  }
+  int getLength1() {
+    return strlen(s1_);
+  }
+  int getLength2() {
+    return strlen(s2_);
+  }
+  bool equals(int index1, int index2) {
+    return s1_[index1] == s2_[index2];
+  }
+
+ private:
+  const char* s1_;
+  const char* s2_;
+};
+
+
+class DiffChunkStruct : public ZoneObject {
+ public:
+  DiffChunkStruct(int pos1_param, int pos2_param,
+                  int len1_param, int len2_param)
+      : pos1(pos1_param), pos2(pos2_param),
+        len1(len1_param), len2(len2_param), next(NULL) {}
+  int pos1;
+  int pos2;
+  int len1;
+  int len2;
+  DiffChunkStruct* next;
+};
+
+
+class ListDiffOutputWriter : public Compare::Output {
+ public:
+  explicit ListDiffOutputWriter(DiffChunkStruct** next_chunk_pointer)
+      : next_chunk_pointer_(next_chunk_pointer) {
+    (*next_chunk_pointer_) = NULL;
+  }
+  void AddChunk(int pos1, int pos2, int len1, int len2) {
+    current_chunk_ = new DiffChunkStruct(pos1, pos2, len1, len2);
+    (*next_chunk_pointer_) = current_chunk_;
+    next_chunk_pointer_ = &current_chunk_->next;
+  }
+ private:
+  DiffChunkStruct** next_chunk_pointer_;
+  DiffChunkStruct* current_chunk_;
+};
+
+
+void CompareStringsOneWay(const char* s1, const char* s2,
+                          int expected_diff_parameter = -1) {
+  StringCompareInput input(s1, s2);
+
+  ZoneScope zone_scope(DELETE_ON_EXIT);
+
+  DiffChunkStruct* first_chunk;
+  ListDiffOutputWriter writer(&first_chunk);
+
+  Compare::CalculateDifference(&input, &writer);
+
+  int len1 = strlen(s1);
+  int len2 = strlen(s2);
+
+  int pos1 = 0;
+  int pos2 = 0;
+
+  int diff_parameter = 0;
+
+  for (DiffChunkStruct* chunk = first_chunk;
+      chunk != NULL;
+      chunk = chunk->next) {
+    int diff_pos1 = chunk->pos1;
+    int similar_part_length = diff_pos1 - pos1;
+    int diff_pos2 = pos2 + similar_part_length;
+
+    ASSERT_EQ(diff_pos2, chunk->pos2);
+
+    for (int j = 0; j < similar_part_length; j++) {
+      ASSERT(pos1 + j < len1);
+      ASSERT(pos2 + j < len2);
+      ASSERT_EQ(s1[pos1 + j], s2[pos2 + j]);
+    }
+    diff_parameter += chunk->len1 + chunk->len2;
+    pos1 = diff_pos1 + chunk->len1;
+    pos2 = diff_pos2 + chunk->len2;
+  }
+  {
+    // After last chunk.
+    int similar_part_length = len1 - pos1;
+    ASSERT_EQ(similar_part_length, len2 - pos2);
+    USE(len2);
+    for (int j = 0; j < similar_part_length; j++) {
+      ASSERT(pos1 + j < len1);
+      ASSERT(pos2 + j < len2);
+      ASSERT_EQ(s1[pos1 + j], s2[pos2 + j]);
+    }
+  }
+
+  if (expected_diff_parameter != -1) {
+    ASSERT_EQ(expected_diff_parameter, diff_parameter);
+  }
+}
+
+
+void CompareStrings(const char* s1, const char* s2,
+                    int expected_diff_parameter = -1) {
+  CompareStringsOneWay(s1, s2, expected_diff_parameter);
+  CompareStringsOneWay(s2, s1, expected_diff_parameter);
+}
+
+}  // Anonymous namespace.
+
+
+// --- T h e   A c t u a l   T e s t s
+
+TEST(LiveEditDiffer) {
+  CompareStrings("zz1zzz12zz123zzz", "zzzzzzzzzz", 6);
+  CompareStrings("zz1zzz12zz123zzz", "zz0zzz0zz0zzz", 9);
+  CompareStrings("123456789", "987654321", 16);
+  CompareStrings("zzz", "yyy", 6);
+  CompareStrings("zzz", "zzz12", 2);
+  CompareStrings("zzz", "21zzz", 2);
+  CompareStrings("cat", "cut", 2);
+  CompareStrings("ct", "cut", 1);
+  CompareStrings("cat", "ct", 1);
+  CompareStrings("cat", "cat", 0);
+  CompareStrings("", "", 0);
+  CompareStrings("cat", "", 3);
+  CompareStrings("a cat", "a capybara", 7);
+  CompareStrings("abbabababababaaabbabababababbabbbbbbbababa",
+                 "bbbbabababbbabababbbabababababbabbababa");
+}