Update RulesManagerService after APEX files
Context
=======
The "time zone updates via APK" feature was implemented in O-MR1 to enable
devices to take time zone updates via an APK update and without needing
an OTA. RulesManagerService is an important part of the time zone updates via
APK feature. When RulesManagerService was implemented things were simple; there
was a copy of time zone data in /system. A new (optional) copy was introduced
in /data that could be managed / updated by the RulesManagerService.
Since there were only two copies the /system copy was referred to as the
"system" data.
With the introduction of the runtime APEX and time zone data APEX things
have become more complicated. Android devices can have time zone data in
several places:
1 The copy in /system/usr/share/zoneinfo/ is partially complete and remains
for legacy usecases, e.g. binaries that "know" about the /system path and
cannot be updated, or binaries which run before /apex paths are mounted.
2 The copy in /apex/com.android.runtime/ is a complete set of time zone
data that can be used by libraries on the device.
3 The copy in /apex/com.android.tzdata/ is the "overlay" copy for use when
the time zone data APEX can be updated. For devices that can take APEX
updates it will be present and is expected to start with the same version as
present in /apex/com.android.runtime. Note: Nothing in the code *requires*
this copy to be present but it is expected to be present in most cases.
RulesManagerService is being kept around for devices that may not have the
capability of updating their APEX files but which still want to update time
zone data without taking an OTA. It is assumed that RulesManagerService will
*only* be turned on in these situations and *not* when the time zone
data in /apex/com.android.tzdata/ might actually be updated independently of
the copy in /apex/com.android.runtime/.
The RulesManagerService therefore adds the fourth copy of the data that *could*
be present:
4 The copy /data/misc/zoneinfo/ managed by RulesManagerService.
Important libraries / binaries on device know about all 4 copies and
prioritize them in order 4, 3, 2, 1. i.e. the libraries will use the
first copy of data found in that order.
In scenarios where RulesManagerService is disabled, 4 will not be present
and therefore 3 will be used (or 2 if 3 is also not present).
In scenarios where RulesManagersService is enabled, 4 is present iff an
APK update has been received. It is assumed that *if* /apex/com.android.tzdata/
is present, it contains the same version of tz data as in
/apex/com.android.runtime/, will never be updated, and can therefore
be ignored by RulesManagerService.
The changes
===========
This commit and others in the same topic do the following:
1) Change RulesManagerService references to "system" data to "base" data in a
valiant attempt to limit confusion until it can be removed.
2) Switch RulesManagerService over from using the data in
/system/usr/share/zoneinfo/ as base data to the data in
/apex/com.android.runtime/. As part of this change, the RulesManagerService
can now use the tz_version file to identify the version of tzdb in "base"
rather than reading the header of the tzdata file, so that is done
here too.
3) Update imports neccessary to meet pre-upload check requirements.
Note: tzdatacheck, an independent binary that manages time zone data
after OTA, was updated to use /apex/com.android.runtime/ instead of
/system/usr/share/zoneinfo/ in commit c6a2737e0861472d1726ed472708d7762ab1e802.
Bug: 119293618
Bug: 113373927
Test: atest FrameworksCoreTests:android.app.timezone
Test: atest FrameworksServicesTests:com.android.server.timezone
Test: CTS: run cts-dev -m CtsLibcoreTestCases -t libcore.libcore.timezone.ZoneInfoDBTest
Test: CTS: run cts-dev -m CtsLibcoreTestCases -t libcore.libcore.icu.TimeZoneIntegrationTest
Change-Id: Idabe245c7ad337938c202b1796ce9d89ec68bbd6
4 files changed