From: =?utf-8?q?Andr=C3=A9_Bargull?= <andrebargull@googlemail.com>

Date: Wed, 8 Nov 2017 03:23:41 -0800

Subject: Always use the equivalent year to determine the time zone offset and

 name

Reviewed-by: Jeff Walden

Bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1415202

Bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1479687

Origin: upstream

Applied-upstream: 62, commit:https://hg.mozilla.org/mozilla-central/rev/ce9f1466ec78

---

 js/src/jsdate.cpp  | 11 +++++++----

 js/src/vm/Time.cpp | 14 ++++----------

 js/src/vm/Time.h   |  2 +-

 3 files changed, 12 insertions(+), 15 deletions(-)

diff --git a/js/src/jsdate.cpp b/js/src/jsdate.cpp

index 07af3d18c865..ff8fd6c3763c 100644

--- a/js/src/jsdate.cpp

+++ b/js/src/jsdate.cpp

@@ -2353,12 +2353,15 @@ static PRMJTime ToPRMJTime(double localTime, double utcTime) {

 static size_t FormatTime(char* buf, int buflen, const char* fmt, double utcTime,

                          double localTime) {

   PRMJTime prtm = ToPRMJTime(localTime, utcTime);

-  int eqivalentYear = IsRepresentableAsTime32(utcTime)

-                          ? prtm.tm_year

-                          : EquivalentYearForDST(prtm.tm_year);

+  // If an equivalent year was used to compute the date/time components, use

+  // the same equivalent year to determine the time zone name and offset in

+  // PRMJ_FormatTime(...).

+  int timeZoneYear = IsRepresentableAsTime32(utcTime)

+                     ? prtm.tm_year

+                     : EquivalentYearForDST(prtm.tm_year);

   int offsetInSeconds = (int)floor((localTime - utcTime) / msPerSecond);

-  return PRMJ_FormatTime(buf, buflen, fmt, &prtm, eqivalentYear,

+  return PRMJ_FormatTime(buf, buflen, fmt, &prtm, timeZoneYear,

                          offsetInSeconds);

 }

diff --git a/js/src/vm/Time.cpp b/js/src/vm/Time.cpp

index f59977f0d0e9..5ee4794b3e83 100644

--- a/js/src/vm/Time.cpp

+++ b/js/src/vm/Time.cpp

@@ -247,7 +247,7 @@ static void PRMJ_InvalidParameterHandler(const wchar_t* expression,

 /* Format a time value into a buffer. Same semantics as strftime() */

 size_t PRMJ_FormatTime(char* buf, int buflen, const char* fmt,

-                       const PRMJTime* prtm, int equivalentYear,

+                       const PRMJTime* prtm, int timeZoneYear,

                        int offsetInSeconds) {

   size_t result = 0;

 #if defined(XP_UNIX) || defined(XP_WIN)

@@ -280,7 +280,8 @@ size_t PRMJ_FormatTime(char* buf, int buflen, const char* fmt,

      * Fill out |td| to the time represented by |prtm|, leaving the

      * timezone fields zeroed out. localtime_r will then fill in the

      * timezone fields for that local time according to the system's

-     * timezone parameters.

+     * timezone parameters. Use |timeZoneYear| for the year to ensure the

+     * time zone name matches the time zone offset used by the caller.

      */

     struct tm td;

     memset(&td, 0, sizeof(td));

@@ -290,19 +291,12 @@ size_t PRMJ_FormatTime(char* buf, int buflen, const char* fmt,

     td.tm_mday = prtm->tm_mday;

     td.tm_mon = prtm->tm_mon;

     td.tm_wday = prtm->tm_wday;

-    td.tm_year = prtm->tm_year - 1900;

+    td.tm_year = timeZoneYear - 1900;

     td.tm_yday = prtm->tm_yday;

     td.tm_isdst = prtm->tm_isdst;

     time_t t = mktime(&td);

-    // If |prtm| cannot be represented in |time_t| the year is probably

-    // out of range, try again with the DST equivalent year.

-    if (t == static_cast<time_t>(-1)) {

-      td.tm_year = equivalentYear - 1900;

-      t = mktime(&td);

-    }

-

     // If either mktime or localtime_r failed, fill in the fallback time

     // zone offset |offsetInSeconds| and set the time zone identifier to

     // the empty string.

diff --git a/js/src/vm/Time.h b/js/src/vm/Time.h

index 3a51d869c922..37b7faeec028 100644

--- a/js/src/vm/Time.h

+++ b/js/src/vm/Time.h

@@ -49,7 +49,7 @@ inline void PRMJ_NowShutdown() {}

 /* Format a time value into a buffer. Same semantics as strftime() */

 extern size_t PRMJ_FormatTime(char* buf, int buflen, const char* fmt,

-                              const PRMJTime* tm, int equivalentYear,

+                              const PRMJTime* tm, int timeZoneYear,

                               int offsetInSeconds);

 /**

--

2.21.0