Hands-on

AOSP source tour

Learn to read the real source, with ten guided quests.

5 pages60 min5 interactive8400 words

01How to read AOSPAOSP is tens of millions of lines across thousands of repositories. Reading it is a skill with a method: find the entry point, follow the Binder boundary, read the build file, and ignore the generated code. This page teaches the method.intermediate13 mininteractive
02The directory mapWhere everything lives, top to bottom: what frameworks/base actually contains, why packages/apps is not the framework, what system/core owns, and which directories are reference targets rather than platform code.intermediate12 mininteractive
03Ten reading questsTen source-reading quests, each with a question and a place to look: the zygote fork, the init language, a system service's birth, the framework facade, an IPC call, package install, the frame loop, permissions, intent resolution, and a Mainline boundary.nerd11 mininteractive
04Building AOSPWhat a build actually involves: repo and the manifest, envsetup and lunch, Soong and Ninja, and why a full build is measured in hours and hundreds of gigabytes. This page explains the pipeline rather than pretending you can follow along on a laptop.nerd12 mininteractive
05ContributingHow a change actually gets into AOSP: the Gerrit review flow, the CLA, repo upload, and the fact that approval requires a code owner — almost all of whom work at Google. What an outside contributor can realistically expect.nerd12 mininteractive

Test yourself

Test yourself: AOSP source tour

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Put these steps of the reading method for a subsystem in the order the page recommends.

Drag, or use the arrows to reorder.

1The state: what data structures hold the truth, and who mutates them
2The concurrency: which lock protects the state
3The service's main loop and initialisation
4The interface: the AIDL or public API
5The failure paths: timeouts, death, invalid arguments