| commit | 1ab82627788f5059406be4e5e165d8dfb776fff1 | [log] [tgz] |
|---|---|---|
| author | Linux Build Service Account <lnxbuild@localhost> | Sun Jan 15 14:59:33 2023 -0800 |
| committer | Linux Build Service Account <lnxbuild@localhost> | Sun Jan 15 14:59:33 2023 -0800 |
| tree | d3f547e4a86665d1cfc14a4caebc65db67b0ffa8 | |
| parent | 07fde6bd0e9df35787081d2daa94a0aff586096e [diff] | |
| parent | 48c754e7c969c04dbf14e8fb8c56f012e1998a65 [diff] |
Merge 48c754e7c969c04dbf14e8fb8c56f012e1998a65 on remote branch Change-Id: Iddd8fc3ad5049a0ee0fce7b0599f3e8f13b1bf6a
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.