Replace non-threadsafe gmtime and setlocale

Make DateTimeStrFormat use boost::posix_time.

Also re-enable the util_DateTimeStrFormat tests, as they are no
longer platform specific.

src/rpcprotocol.cpp

@@ -51,15 +51,7 @@ string HTTPPost(const string& strMsg, const map<string,string>& mapRequestHeader
 
 static string rfc1123Time()
 {
-    char buffer[64];
-    time_t now;
-    time(&now);
-    struct tm* now_gmt = gmtime(&now);
-    string locale(setlocale(LC_TIME, NULL));
-    setlocale(LC_TIME, "C"); // we want POSIX (aka "C") weekday/month strings
-    strftime(buffer, sizeof(buffer), "%a, %d %b %Y %H:%M:%S +0000", now_gmt);
-    setlocale(LC_TIME, locale.c_str());
-    return string(buffer);
+    return DateTimeStrFormat("%a, %d %b %Y %H:%M:%S +0000", GetTime());
 }
 
 string HTTPReply(int nStatus, const string& strMsg, bool keepalive)

src/test/util_tests.cpp

@@ -108,13 +108,11 @@ BOOST_AUTO_TEST_CASE(util_HexStr)
 
 BOOST_AUTO_TEST_CASE(util_DateTimeStrFormat)
 {
-/*These are platform-dependant and thus removed to avoid useless test failures
     BOOST_CHECK_EQUAL(DateTimeStrFormat("%Y-%m-%d %H:%M:%S", 0), "1970-01-01 00:00:00");
     BOOST_CHECK_EQUAL(DateTimeStrFormat("%Y-%m-%d %H:%M:%S", 0x7FFFFFFF), "2038-01-19 03:14:07");
-    // Formats used within Bitcoin
     BOOST_CHECK_EQUAL(DateTimeStrFormat("%Y-%m-%d %H:%M:%S", 1317425777), "2011-09-30 23:36:17");
     BOOST_CHECK_EQUAL(DateTimeStrFormat("%Y-%m-%d %H:%M", 1317425777), "2011-09-30 23:36");
-*/
+    BOOST_CHECK_EQUAL(DateTimeStrFormat("%a, %d %b %Y %H:%M:%S +0000", 1317425777), "Fri, 30 Sep 2011 23:36:17 +0000");
 }
 
 BOOST_AUTO_TEST_CASE(util_ParseParameters)

src/util.cpp

@@ -14,6 +14,8 @@
 
 #include <stdarg.h>
 
+#include <boost/date_time/posix_time/posix_time.hpp>
+
 #ifndef WIN32
 // for posix_fallocate
 #ifdef __linux_
@@ -1400,3 +1402,13 @@ void SetupEnvironment()
     }
     #endif
 }
+
+std::string DateTimeStrFormat(const char* pszFormat, int64_t nTime)
+{
+    // std::locale takes ownership of the pointer
+    std::locale loc(std::locale::classic(), new boost::posix_time::time_facet(pszFormat));
+    std::stringstream ss;
+    ss.imbue(loc);
+    ss << boost::posix_time::from_time_t(nTime);
+    return ss.str();
+}

src/util.h

@@ -325,14 +325,7 @@ inline int64_t GetTimeMicros()
             boost::posix_time::ptime(boost::gregorian::date(1970,1,1))).total_microseconds();
 }
 
-inline std::string DateTimeStrFormat(const char* pszFormat, int64_t nTime)
-{
-    time_t n = nTime;
-    struct tm* ptmTime = gmtime(&n);
-    char pszTime[200];
-    strftime(pszTime, sizeof(pszTime), pszFormat, ptmTime);
-    return pszTime;
-}
+std::string DateTimeStrFormat(const char* pszFormat, int64_t nTime);
 
 inline bool IsSwitchChar(char c)
 {