ICU-6488 mutex cleanup in timezone code

X-SVN-Rev: 24452

icu4c/source/i18n/timezone.cpp

@@ -107,6 +107,7 @@ static U_NAMESPACE_QUALIFIER TimeZone*  DEFAULT_ZONE = NULL;
 static U_NAMESPACE_QUALIFIER TimeZone*  _GMT = NULL; // cf. TimeZone::GMT
 
 static char TZDATA_VERSION[16];
+static UBool TZDataVersionInitialized = FALSE;
 
 #ifdef U_USE_TIMEZONE_OBSOLETE_2_8
 static U_NAMESPACE_QUALIFIER UnicodeString* OLSON_IDS = 0;
@@ -127,6 +128,7 @@ static UBool U_CALLCONV timeZone_cleanup(void)
     _GMT = NULL;
 
     uprv_memset(TZDATA_VERSION, 0, sizeof(TZDATA_VERSION));
+    TZDataVersionInitialized = FALSE;
 
     if (LOCK) {
         umtx_destroy(&LOCK);
@@ -383,12 +385,15 @@ TimeZone::getGMT(void)
     // Initialize _GMT independently of other static data; it should
     // be valid even if we can't load the time zone UDataMemory.
     if (needsInit) {
+        SimpleTimeZone *tmpGMT = new SimpleTimeZone(0, UnicodeString(TRUE, GMT_ID, GMT_ID_LENGTH));
         umtx_lock(&LOCK);
         if (_GMT == 0) {
-            _GMT = new SimpleTimeZone(0, UnicodeString(TRUE, GMT_ID, GMT_ID_LENGTH));
-            ucln_i18n_registerCleanup(UCLN_I18N_TIMEZONE, timeZone_cleanup);
+            _GMT = tmpGMT;
+            tmpGMT = NULL;
         }
         umtx_unlock(&LOCK);
+        ucln_i18n_registerCleanup(UCLN_I18N_TIMEZONE, timeZone_cleanup);
+        delete tmpGMT;
     }
     return _GMT;
 }
@@ -576,46 +581,6 @@ TimeZone::initDefault()
         default_zone = NULL;
     }
 
-#if 0
-    // NOTE: As of ICU 2.8, we no longer have an offsets table, since
-    // historical zones can change offset over time.  If we add
-    // build-time heuristics to infer the "most frequent" raw offset
-    // of a zone, we can build tables and institute defaults, as done
-    // in ICU <= 2.6.
-
-    // If we couldn't get the time zone ID from the host, use
-    // the default host timezone offset.  Further refinements
-    // to this include querying the host to determine if DST
-    // is in use or not and possibly using the host locale to
-    // select from multiple zones at a the same offset.  We
-    // don't do any of this now, but we could easily add this.
-    if (default_zone == NULL) {
-        // Use the designated default in the time zone list that has the
-        // appropriate GMT offset, if there is one.
-
-        const OffsetIndex* index = INDEX_BY_OFFSET;
-
-        for (;;) {
-            if (index->gmtOffset > rawOffset) {
-                // Went past our desired offset; no match found
-                break;
-            }
-            if (index->gmtOffset == rawOffset) {
-                // Found our desired offset
-                default_zone = createSystemTimeZone(ZONE_IDS[index->defaultZone]);
-                break;
-            }
-            // Compute the position of the next entry.  If the delta value
-            // in this entry is zero, then there is no next entry.
-            uint16_t delta = index->nextEntryDelta;
-            if (delta == 0) {
-                break;
-            }
-            index = (const OffsetIndex*)((int8_t*)index + delta);
-        }
-    }
-#endif
-
     // Construct a fixed standard zone with the host's ID
     // and raw offset.
     if (default_zone == NULL) {
@@ -669,7 +634,6 @@ TimeZone::adoptDefault(TimeZone* zone)
     {
         TimeZone* old = NULL;
 
-        umtx_init(&LOCK);   /* This is here to prevent race conditions. */
         umtx_lock(&LOCK);
         old = DEFAULT_ZONE;
         DEFAULT_ZONE = zone;
@@ -1458,19 +1422,26 @@ TimeZone::getTZDataVersion(UErrorCode& status)
 {
     /* This is here to prevent race conditions. */
     UBool needsInit;
-    UMTX_CHECK(&LOCK, (TZDATA_VERSION[0] == 0), needsInit);
+    UMTX_CHECK(&LOCK, !TZDataVersionInitialized, needsInit);
     if (needsInit) {
-        int32_t len = sizeof(TZDATA_VERSION);
+        int32_t len = 0;
         UResourceBundle *bundle = ures_openDirect(NULL, "zoneinfo", &status);
         const UChar *tzver = ures_getStringByKey(bundle, "TZVersion",
             &len, &status);
 
-        umtx_lock(&LOCK);
         if (U_SUCCESS(status)) {
-            u_UCharsToChars(tzver, TZDATA_VERSION, len+1);
+            if (len >= sizeof(TZDATA_VERSION)) {
+                // Ensure that there is always space for a trailing nul in TZDATA_VERSION
+                len = sizeof(TZDATA_VERSION) - 1;
+            }
+            umtx_lock(&LOCK);
+            if (!TZDataVersionInitialized) {
+                u_UCharsToChars(tzver, TZDATA_VERSION, len);
+                TZDataVersionInitialized = TRUE;
+            }
+            umtx_unlock(&LOCK);
             ucln_i18n_registerCleanup(UCLN_I18N_TIMEZONE, timeZone_cleanup);
         }
-        umtx_unlock(&LOCK);
 
         ures_close(bundle);
     }

icu4c/source/i18n/zonemeta.cpp

@@ -664,19 +664,21 @@ ZoneMeta::initialize(void) {
     Hashtable *tmpMetaToOlson = createMetaToOlsonMap();
 
     umtx_lock(&gZoneMetaLock);
-    if (gZoneMetaInitialized) {
-        // Another thread already created mappings
-        delete tmpCanonicalMap;
-        delete tmpOlsonToMeta;
-        delete tmpMetaToOlson;
-    } else {
+    if (!gZoneMetaInitialized) {
         gCanonicalMap = tmpCanonicalMap;
         gOlsonToMeta = tmpOlsonToMeta;
         gMetaToOlson = tmpMetaToOlson;
+        tmpCanonicalMap = NULL;
+        tmpOlsonToMeta = NULL;
+        tmpMetaToOlson = NULL;
         gZoneMetaInitialized = TRUE;
-        ucln_i18n_registerCleanup(UCLN_I18N_ZONEMETA, zoneMeta_cleanup);
     }
     umtx_unlock(&gZoneMetaLock);
+    
+    ucln_i18n_registerCleanup(UCLN_I18N_ZONEMETA, zoneMeta_cleanup);
+    delete tmpCanonicalMap;
+    delete tmpOlsonToMeta;
+    delete tmpMetaToOlson;
 }
 
 UnicodeString& U_EXPORT2