commit | 7dca200ee6746556654d095de30bd22eb15ac97b | [log] [tgz] |
---|---|---|
author | Anton Hansson <hansson@google.com> | Wed Apr 20 10:32:17 2022 +0000 |
committer | Android (Google) Code Review <android-gerrit@google.com> | Wed Apr 20 10:32:17 2022 +0000 |
tree | e0b34344be4b2cdcf80b1ffdd764a241a3e70581 | |
parent | 4fdba71eabe8b82cb9cbc5221906226593b76c84 [diff] | |
parent | 6cb82adcad13d51457cf4ffaa76604196345714f [diff] |
Merge "Bump SDK Extension version to 3" into tm-dev
SdkExtensions module is responsible for:
The module is packaged in an apex, com.android.sdkext
, and has several components:
bin/derive_classpath
: a native binary that runs early in the device boot process. It reads individual classpath configs files from the system and other modules, merges them, and defines the definition of *CLASSPATH environ variables.bin/derive_sdk
: native binary that runs early in the device boot process and reads metadata of other modules, to set system properties relating to the extension SDK (for instance build.version.extensions.r
).javalib/framework-sdkextension.jar
: this is a jar on the bootclasspath that exposes APIs to applications to query the extension SDK level.derive_sdk
is a program that reads metadata stored in other apex modules, in the form of binary protobuf files in subpath etc/sdkinfo.pb
inside each apex. The structure of this protobuf can be seen here. The exact steps for converting a set of metadata files to actual extension versions is likely to change over time, and should not be depended upon.
The module exposes a java class SdkExtensions
in the package android.os.ext
. The method getExtensionVersion(int)
can be used to read the version of a particular sdk extension, e.g. getExtensionVersion(Build.VERSION_CODES.R)
.
derive_classpath
service reads and merges individual config files in the /system/etc/classpaths/
and /apex/*/etc/classpaths
. Each config stores protobuf message from classpaths.proto
in a proto binary format. Exact merging algorithm that determines the order of the classpath entries is described in derive_classpath.cpp
and may change over time.
An extension is a way to group a set of modules so that they are versioned together. We currently define a new extension for every Android SDK level that introduces new modules. Every module shipped in previous versions are also part of the new extension. For example, all the R modules are part of both the R extensions and the S extensions.
The steps to define a new extension are:
derive_sdk.cpp
by:GetSdkLevel
with the new enum setderive_sdk_test.cpp
verifying the new extensions workSdkExtensions.getExtensionVersion
API support the new extensions.