If no NITZ information use Country Code to set TimeZone.

This is not perfect and only works if the CC is known via
the GSM radio and is only accurate if there is one time zone
per country. This does nothing to resolve time zone problems
for wifi only devices.

So this is a partial fix for bug 2896745

Bug: 2896745
Change-Id: I78f013836c4e4870b8b1016a8312f5adbe0d31c9

1 files changed, 131 insertions, 30 deletions

diff --git a/core/java/android/util/TimeUtils.java b/core/java/android/util/TimeUtils.java
index 93299eb..2883eca 100644
--- a/core/java/android/util/TimeUtils.java
+++ b/core/java/android/util/TimeUtils.java
@@ -25,6 +25,8 @@ import org.xmlpull.v1.XmlPullParserException;
 
 import java.io.IOException;
 import java.io.PrintWriter;
+import java.util.ArrayList;
+import java.util.Collection;
 import java.util.TimeZone;
 import java.util.Date;
 
@@ -35,18 +37,26 @@ import com.android.internal.util.XmlUtils;
  */
 public class TimeUtils {
     /** @hide */ public TimeUtils() {}
+    private static final boolean DBG = false;
     private static final String TAG = "TimeUtils";
 
+    /** Cached results of getTineZones */
+    private static final Object sLastLockObj = new Object();
+    private static ArrayList<TimeZone> sLastZones = null;
+    private static String sLastCountry = null;
+
+    /** Cached results of getTimeZonesWithUniqueOffsets */
+    private static final Object sLastUniqueLockObj = new Object();
+    private static ArrayList<TimeZone> sLastUniqueZoneOffsets = null;
+    private static String sLastUniqueCountry = null;
+
+
     /**
      * Tries to return a time zone that would have had the specified offset
      * and DST value at the specified moment in the specified country.
      * Returns null if no suitable zone could be found.
      */
     public static TimeZone getTimeZone(int offset, boolean dst, long when, String country) {
-        if (country == null) {
-            return null;
-        }
-
         TimeZone best = null;
 
         Resources r = Resources.getSystem();
@@ -58,6 +68,107 @@ public class TimeUtils {
         int currentOffset = current.getOffset(when);
         boolean currentDst = current.inDaylightTime(d);
 
+        for (TimeZone tz : getTimeZones(country)) {
+            // If the current time zone is from the right country
+            // and meets the other known properties, keep it
+            // instead of changing to another one.
+
+            if (tz.getID().equals(currentName)) {
+                if (currentOffset == offset && currentDst == dst) {
+                    return current;
+                }
+            }
+
+            // Otherwise, take the first zone from the right
+            // country that has the correct current offset and DST.
+            // (Keep iterating instead of returning in case we
+            // haven't encountered the current time zone yet.)
+
+            if (best == null) {
+                if (tz.getOffset(when) == offset &&
+                    tz.inDaylightTime(d) == dst) {
+                    best = tz;
+                }
+            }
+        }
+
+        return best;
+    }
+
+    /**
+     * Return list of unique time zones for the country. Do not modify
+     *
+     * @param country to find
+     * @return list of unique time zones, maybe empty but never null. Do not modify.
+     * @hide
+     */
+    public static ArrayList<TimeZone> getTimeZonesWithUniqueOffsets(String country) {
+        synchronized(sLastUniqueLockObj) {
+            if ((country != null) && country.equals(sLastUniqueCountry)) {
+                if (DBG) {
+                    Log.d(TAG, "getTimeZonesWithUniqueOffsets(" +
+                            country + "): return cached version");
+                }
+                return sLastUniqueZoneOffsets;
+            }
+        }
+
+        Collection<TimeZone> zones = getTimeZones(country);
+        ArrayList<TimeZone> uniqueTimeZones = new ArrayList<TimeZone>();
+        for (TimeZone zone : zones) {
+            // See if we already have this offset,
+            // Using slow but space efficient and these are small.
+            boolean found = false;
+            for (int i = 0; i < uniqueTimeZones.size(); i++) {
+                if (uniqueTimeZones.get(i).getRawOffset() == zone.getRawOffset()) {
+                    found = true;
+                    break;
+                }
+            }
+            if (found == false) {
+                if (DBG) {
+                    Log.d(TAG, "getTimeZonesWithUniqueOffsets: add unique offset=" +
+                            zone.getRawOffset() + " zone.getID=" + zone.getID());
+                }
+                uniqueTimeZones.add(zone);
+            }
+        }
+
+        synchronized(sLastUniqueLockObj) {
+            // Cache the last result
+            sLastUniqueZoneOffsets = uniqueTimeZones;
+            sLastUniqueCountry = country;
+
+            return sLastUniqueZoneOffsets;
+        }
+    }
+
+    /**
+     * Returns the time zones for the country, which is the code
+     * attribute of the timezone element in time_zones_by_country.xml. Do not modify.
+     *
+     * @param country is a two character country code.
+     * @return TimeZone list, maybe empty but never null. Do not modify.
+     * @hide
+     */
+    public static ArrayList<TimeZone> getTimeZones(String country) {
+        synchronized (sLastLockObj) {
+            if ((country != null) && country.equals(sLastCountry)) {
+                if (DBG) Log.d(TAG, "getTimeZones(" + country + "): return cached version");
+                return sLastZones;
+            }
+        }
+
+        ArrayList<TimeZone> tzs = new ArrayList<TimeZone>();
+
+        if (country == null) {
+            if (DBG) Log.d(TAG, "getTimeZones(null): return empty list");
+            return tzs;
+        }
+
+        Resources r = Resources.getSystem();
+        XmlResourceParser parser = r.getXml(com.android.internal.R.xml.time_zones_by_country);
+
         try {
             XmlUtils.beginDocument(parser, "timezones");
 
@@ -73,43 +184,33 @@ public class TimeUtils {
 
                 if (country.equals(code)) {
                     if (parser.next() == XmlPullParser.TEXT) {
-                        String maybe = parser.getText();
-
-                        // If the current time zone is from the right country
-                        // and meets the other known properties, keep it
-                        // instead of changing to another one.
-
-                        if (maybe.equals(currentName)) {
-                            if (currentOffset == offset && currentDst == dst) {
-                                return current;
-                            }
-                        }
-
-                        // Otherwise, take the first zone from the right
-                        // country that has the correct current offset and DST.
-                        // (Keep iterating instead of returning in case we
-                        // haven't encountered the current time zone yet.)
-
-                        if (best == null) {
-                            TimeZone tz = TimeZone.getTimeZone(maybe);
-
-                            if (tz.getOffset(when) == offset &&
-                                tz.inDaylightTime(d) == dst) {
-                                best = tz;
+                        String zoneIdString = parser.getText();
+                        TimeZone tz = TimeZone.getTimeZone(zoneIdString);
+                        if (tz.getID().startsWith("GMT") == false) {
+                            // tz.getID doesn't start not "GMT" so its valid
+                            tzs.add(tz);
+                            if (DBG) {
+                                Log.d(TAG, "getTimeZone('" + country + "'): found tz.getID=="
+                                    + ((tz != null) ? tz.getID() : "<no tz>"));
                             }
                         }
                     }
                 }
             }
         } catch (XmlPullParserException e) {
-            Log.e(TAG, "Got exception while getting preferred time zone.", e);
+            Log.e(TAG, "Got xml parser exception getTimeZone('" + country + "'): e=", e);
         } catch (IOException e) {
-            Log.e(TAG, "Got exception while getting preferred time zone.", e);
+            Log.e(TAG, "Got IO exception getTimeZone('" + country + "'): e=", e);
         } finally {
             parser.close();
         }
 
-        return best;
+        synchronized(sLastLockObj) {
+            // Cache the last result;
+            sLastZones = tzs;
+            sLastCountry = country;
+            return sLastZones;
+        }
     }
 
     /**