Implement date library functions in C++.

test/cctest/test-date.cc

+// Copyright 2012 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 "v8.h"
+
+#include "global-handles.h"
+#include "snapshot.h"
+#include "cctest.h"
+
+using namespace v8::internal;
+
+class DateCacheMock: public DateCache {
+ public:
+  struct Rule {
+    int year, start_month, start_day, end_month, end_day, offset_sec;
+  };
+
+  DateCacheMock(int local_offset, Rule* rules, int rules_count)
+      : local_offset_(local_offset), rules_(rules), rules_count_(rules_count) {}
+
+ protected:
+  virtual int GetDaylightSavingsOffsetFromOS(int64_t time_sec) {
+    int days = DaysFromTime(time_sec * 1000);
+    int time_in_day_sec = TimeInDay(time_sec * 1000, days) / 1000;
+    int year, month, day;
+    YearMonthDayFromDays(days, &year, &month, &day);
+    Rule* rule = FindRuleFor(year, month, day, time_in_day_sec);
+    return rule == NULL ? 0 : rule->offset_sec * 1000;
+  }
+
+
+  virtual int GetLocalOffsetFromOS() {
+    return local_offset_;
+  }
+
+ private:
+  Rule* FindRuleFor(int year, int month, int day, int time_in_day_sec) {
+    Rule* result = NULL;
+    for (int i = 0; i < rules_count_; i++)
+      if (Match(&rules_[i], year, month, day, time_in_day_sec)) {
+        result = &rules_[i];
+      }
+    return result;
+  }
+
+
+  bool Match(Rule* rule, int year, int month, int day, int time_in_day_sec) {
+    if (rule->year != 0 && rule->year != year) return false;
+    if (rule->start_month > month) return false;
+    if (rule->end_month < month) return false;
+    int start_day = ComputeRuleDay(year, rule->start_month, rule->start_day);
+    if (rule->start_month == month && start_day > day) return false;
+    if (rule->start_month == month && start_day == day &&
+        2 * 3600 > time_in_day_sec)
+      return false;
+    int end_day = ComputeRuleDay(year, rule->end_month, rule->end_day);
+    if (rule->end_month == month && end_day < day) return false;
+    if (rule->end_month == month && end_day == day &&
+        2 * 3600 <= time_in_day_sec)
+      return false;
+    return true;
+  }
+
+
+  int ComputeRuleDay(int year, int month, int day) {
+    if (day != 0) return day;
+    int days = DaysFromYearMonth(year, month);
+    // Find the first Sunday of the month.
+    while (Weekday(days + day) != 6) day++;
+    return day + 1;
+  }
+
+  int local_offset_;
+  Rule* rules_;
+  int rules_count_;
+};
+
+static int64_t TimeFromYearMonthDay(DateCache* date_cache,
+                                    int year,
+                                    int month,
+                                    int day) {
+  int64_t result = date_cache->DaysFromYearMonth(year, month);
+  return (result + day - 1) * DateCache::kMsPerDay;
+}
+
+static void CheckDST(int64_t time) {
+  Isolate* isolate = Isolate::Current();
+  DateCache* date_cache = isolate->date_cache();
+  int64_t actual = date_cache->ToLocal(time);
+  int64_t expected = time + date_cache->GetLocalOffsetFromOS() +
+                     date_cache->GetDaylightSavingsOffsetFromOS(time / 1000);
+  CHECK_EQ(actual, expected);
+}
+
+
+TEST(DaylightSavingsTime) {
+  LocalContext context;
+  v8::HandleScope scope;
+  Isolate* isolate = Isolate::Current();
+  DateCacheMock::Rule rules[] = {
+    {0, 2, 0, 10, 0, 3600},  // DST from March to November in any year.
+    {2010, 2, 0, 7, 20, 3600},  // DST from March to August 20 in 2010.
+    {2010, 7, 20, 8, 10, 0},  // No DST from August 20 to September 10 in 2010.
+    {2010, 8, 10, 10, 0, 3600},  // DST from September 10 to November in 2010.
+  };
+  DateCacheMock* date_cache =
+    new DateCacheMock(-36000000, rules, sizeof(rules) / sizeof(rules[0]));

[rossberg, 2012/03/06 15:55:50]

What is that constant?
Also, you can use the ARRAY_SIZE macro for the last argument.

[ulan, 2012/03/07 10:55:21]

Done.

+  isolate->set_date_cache(date_cache);

[rossberg, 2012/03/06 15:55:50]

Nit: I wouldn't mind a newline here.

[ulan, 2012/03/07 10:55:21]

Done.

+  int64_t start_of_2010 = TimeFromYearMonthDay(date_cache, 2010, 0, 1);
+  int64_t start_of_2011 = TimeFromYearMonthDay(date_cache, 2011, 0, 1);
+  int64_t august_20 = TimeFromYearMonthDay(date_cache, 2010, 7, 20);
+  int64_t september_10 = TimeFromYearMonthDay(date_cache, 2010, 8, 10);
+  CheckDST((august_20 + september_10) / 2);
+  CheckDST(september_10);
+  CheckDST(september_10 + 2 * 3600);
+  CheckDST(september_10 + 2 * 3600 - 1000);
+  CheckDST(august_20 + 2 * 3600);
+  CheckDST(august_20 + 2 * 3600 - 1000);
+  CheckDST(august_20);
+  // Check each day of 2010.
+  for (int64_t time = start_of_2011 + 2 * 3600;
+       time >= start_of_2010;
+       time -= DateCache::kMsPerDay) {
+    CheckDST(time);
+    CheckDST(time - 1000);
+    CheckDST(time + 1000);
+  }
+  // Check one day from 2010 to 2100.
+  for (int year = 2100; year >= 2010; year--) {
+    CheckDST(TimeFromYearMonthDay(date_cache, year, 5, 5));
+  }
+  CheckDST((august_20 + september_10) / 2);
+  CheckDST(september_10);
+  CheckDST(september_10 + 2 * 3600);
+  CheckDST(september_10 + 2 * 3600 - 1000);
+  CheckDST(august_20 + 2 * 3600);
+  CheckDST(august_20 + 2 * 3600 - 1000);
+  CheckDST(august_20);
+}