[niepce] fwk: make_xmp_date_time() now return whether it failed

[Hubert Figuière <hub src gnome org>]

commit 4e446caff0924e50d8dd7ab7a83ba37731f31061
Author: Hubert Figuière <hub figuiere net>
Date:   Tue Jan 24 12:13:18 2017 -0500

    fwk: make_xmp_date_time() now return whether it failed

 src/fwk/base/date.cpp |   24 ++++++++++++++----------
 src/fwk/base/date.hpp |    6 +++++-
 2 files changed, 19 insertions(+), 11 deletions(-)
---
diff --git a/src/fwk/base/date.cpp b/src/fwk/base/date.cpp
index b8fbac4..3064521 100644
--- a/src/fwk/base/date.cpp
+++ b/src/fwk/base/date.cpp
@@ -47,24 +47,28 @@ time_t make_time_value(const Date & d)
     return date;
 }
 
-XmpDateTime& make_xmp_date_time(time_t t, XmpDateTime& xmp_dt)
+bool make_xmp_date_time(time_t t, XmpDateTime& xmp_dt)
 {
-    // FIXME find a better way. This should work.
     struct tm gmt;
     struct tm* pgmt = gmtime_r(&t, &gmt);
     DBG_ASSERT(pgmt == &gmt, "gmtime failed");
 
-    xmp_dt.year = gmt.tm_year + 1900;
-    xmp_dt.month = gmt.tm_mon + 1;
-    xmp_dt.day = gmt.tm_mday;
-    xmp_dt.hour = gmt.tm_hour;
-    xmp_dt.minute = gmt.tm_min;
-    xmp_dt.second = gmt.tm_sec;
+    if (!pgmt) {
+        return false;
+    }
+
+    xmp_dt.year = pgmt->tm_year + 1900;
+    xmp_dt.month = pgmt->tm_mon + 1;
+    xmp_dt.day = pgmt->tm_mday;
+    xmp_dt.hour = pgmt->tm_hour;
+    xmp_dt.minute = pgmt->tm_min;
+    xmp_dt.second = pgmt->tm_sec;
     xmp_dt.tzSign = 0;
     xmp_dt.tzHour = 0;
     xmp_dt.tzMinute = 0;
     xmp_dt.nanoSecond = 0;
-    return xmp_dt;
+
+    return true;
 }
 
 Date::Date(const XmpDateTime& dt, const Timezone* tz)
@@ -89,7 +93,7 @@ std::string Date::to_string() const
              m_datetime.minute, m_datetime.second,
              m_datetime.tzSign >= 0 ? '+' : '-',
              m_datetime.tzHour, m_datetime.tzMinute);
-    
+
     return buffer;
 }
 
diff --git a/src/fwk/base/date.hpp b/src/fwk/base/date.hpp
index 5435830..89481b3 100644
--- a/src/fwk/base/date.hpp
+++ b/src/fwk/base/date.hpp
@@ -28,7 +28,11 @@ namespace fwk {
 
 class Timezone;
 
-XmpDateTime& make_xmp_date_time(time_t t, XmpDateTime& xmp_dt);
+/**
+ * Fill the XmpDateTime %xmp_dt from a %t
+ * @return false if gmtime_r failed.
+ */
+bool make_xmp_date_time(time_t t, XmpDateTime& xmp_dt);
 
 /**
  * Class to deal with ISO8601 string dates as used by XMP.