src/docs/android_accessing_cpp_switches_in_java.md

Accessing C++ Switches In Java

[TOC]

Introduction

Accessing C++ switches in Java is implemented via a Python script which analyzes the C++ switches file and spits out the corresponding Java class. The generated class name will be based upon the switch file name, and the path must be specified in a comment within the switch file itself.

Usage

1. Add directives to your C++ switch file

   // GENERATED_JAVA_PACKAGE: org.chromium.chrome
   
   // ...snip...
   
   // Documentation for the following switch.
   const char kSomeSwitch[] = "some-switch";
   
   // ...snip...
   

2. Create a template file

    // Copyright {YEAR} The Chromium Authors. All rights reserved.
    // Use of this source code is governed by a BSD-style license that can be
    // found in the LICENSE file.
   
    // This file is autogenerated by
    //     {SCRIPT_NAME}
    // From
    //     {SOURCE_PATH}, and
    //     {TEMPLATE_PATH}
   
    package my.java.package
   
    // Be sure to escape any curly braces in your template by doubling as
    // follows.
    public abstract class MySwitches {{
   
    {NATIVE_SWITCHES}
   
    }}
   

3. Add a new build target

   import("//build/config/android/rules.gni")
   
   java_cpp_strings("foo_generated_switch") {
     sources = [
       "//base/android/native_foo_switches.cc",
     ]
     template = "//base/android/java_templates/MySwitches.java.tmpl"
   }
   

4. Add the new target to the desired android_library targets srcjar_deps:

   android_library("base_java") {
     srcjar_deps = [
       ":foo_generated_switches",
     ]
   }
   

5. The generated file org/chromium/chrome/NativeFooSwitches.java would contain:

   package org.chromium.chrome;
   
   public final class NativeFooSwitches {
       // ...snip...
   
       public static final String SOME_SWITCH = "some-switch";
   
       // ...snip...
   }
   

Code

• Generator code and Tests
• GN template