Revise Windows time-zone mapping to use proper IANA IDs

The CLDR's "IANA" IDs may (for the sake of stability) date back to
before IANA's own naming has been updated. As a result, the "IANA" IDs
we were using were in some cases out of date. CLDR does provide a
mapping from its stable IDs to all aliases and the current IANA name
for each (which I shall soon be needing in other work), so use that to
map the CLDR IDs to contemporary IANA ones.

Revise the documentation of CldrAccess.readWindowsTimeZones() to take
this into account, pass it the alias mapping from the table, use that
to map IDs internally and, in passing, rename a variable.  Update
cldr2qtimezone.py to match the new CldrAccess methods and regenerate
the data.

Change-Id: I23d8a7d048d76392099d125376b544a41faf7eb3
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Mate Barany <mate.barany@qt.io>

util/locale_database/cldr.py

@@ -458,29 +458,40 @@ enumdata.py (keeping the old name as an alias):
 
         return alias, naming
 
-    def readWindowsTimeZones(self, lookup): # For use by cldr2qtimezone.py
+    def readWindowsTimeZones(self, lookup, alias): # For use by cldr2qtimezone.py
         """Digest CLDR's MS-Win time-zone name mapping.
 
-        MS-Win have their own eccentric names for time-zones.  CLDR
-        helpfully provides a translation to more orthodox names.
+        MS-Win have their own eccentric names for time-zones. CLDR
+        helpfully provides a translation to more orthodox names,
+        albeit these are CLDR IDs - see bcp47Aliases() - rather than
+        (up to date) IANA IDs. The windowsZones.xml supplement has
+        supplementalData/windowsZones/mapTimezones/mapZone nodes with
+        attributes
 
-        Single argument, lookup, is a mapping from known MS-Win names
-        for locales to a unique integer index (starting at 1).
+          territory -- using 001 (World) for 'default'
+          type -- space-joined sequence of CLDR IDs of zones
+          other -- Windows name of these zones in the given territory
 
-        The XML structure we read has the form:
+        First argument, lookup, is a mapping from known MS-Win names
+        for timezones to a unique integer index (starting at 1). Second
+        argument, alias, should be the first part of the pair returned
+        by a call to bcp47Aliases(); it shall be used to transform
+        CLDR IDs into IANA IDs.
 
- <supplementalData>
-     <windowsZones>
-         <mapTimezones otherVersion="..." typeVersion="...">
-             <!-- (UTC-08:00) Pacific Time (US & Canada) -->
-             <mapZone other="Pacific Standard Time" territory="001" type="America/Los_Angeles"/>
-             <mapZone other="Pacific Standard Time" territory="CA" type="America/Vancouver America/Dawson America/Whitehorse"/>
-             <mapZone other="Pacific Standard Time" territory="US" type="America/Los_Angeles America/Metlakatla"/>
-             <mapZone other="Pacific Standard Time" territory="ZZ" type="PST8PDT"/>
-         </mapTimezones>
-     </windowsZones>
- </supplementalData>
-"""
+        For each mapZone node, its territory is mapped to a
+        QLocale::Territory enum with numeric value code e, its other
+        is mapped through lookup to obtain an MS-Win name index k and
+        its type is split on spacing and cleaned up as follows. Each
+        entry in type is mapped, via alias (if present in it) to get a
+        list of IANA IDs, omitting any later duplicates from earlier
+        entries; the result list of IANA IDs is joined with spaces
+        between to give a string s.
+
+        Returns a triple (version, defaults, windows) in which version
+        is the version of CLDR in use, defaults is a mapping {k: s}
+        and windows is a mapping {(k, e): b} in which b maps
+        'windowsId' to the Windows name of the zone (the node's other
+        attribute), 'territoryCode' to e and 'ianaList' to s."""
         zones = self.supplement('windowsZones.xml')
         enum = self.__enumMap('territory')
         badZones, unLands, defaults, windows = set(), set(), {}, {}
@@ -490,9 +501,17 @@ enumdata.py (keeping the old name as an alias):
                 continue
 
             wid, code = attrs['other'], attrs['territory']
+            cldrs, ianas = attrs['type'].split(), []
+            for cldr in cldrs:
+                if cldr in alias:
+                    iana = alias[cldr]
+                    if iana not in ianas:
+                        ianas.append(iana)
+                else:
+                    ianas.append(cldr)
             data = dict(windowsId = wid,
                         territoryCode = code,
-                        ianaList = ' '.join(attrs['type'].split()))
+                        ianaList = ' '.join(ianas))
 
             try:
                 key = lookup[wid]
@@ -505,12 +524,12 @@ enumdata.py (keeping the old name as an alias):
                 defaults[key] = data['ianaList']
             else:
                 try:
-                    cid, name = enum[code]
+                    land, name = enum[code]
                 except KeyError:
                     unLands.append(code)
                     continue
-                data.update(territoryId = cid, territory = name)
-                windows[key, cid] = data
+                data.update(territoryId = land, territory = name)
+                windows[key, land] = data
 
         if unLands:
             raise Error('Unknown territory codes, please add to enumdata.py: '

util/locale_database/cldr2qtimezone.py

@@ -173,7 +173,8 @@ def main(out, err):
 
     try:
         version, defaults, winIds = access.readWindowsTimeZones(
-            {name: ind for ind, name in enumerate((x[0] for x in windowsIdList), 1)})
+            {name: ind for ind, name in enumerate((k for k, v in windowsIdList), 1)},
+            alias)
     except IOError as e:
         parser.error(
             f'Failed to open common/supplemental/windowsZones.xml: {e}')