7b017a99d8
No-Try: true Bug: 1098010 Change-Id: Id44652c3572c46c4ec732b69473fb951749d35eb Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3878321 Commit-Queue: Avi Drissman <avi@chromium.org> Owners-Override: Avi Drissman <avi@chromium.org> Reviewed-by: Mark Mentovai <mark@chromium.org> Auto-Submit: Avi Drissman <avi@chromium.org> Cr-Commit-Position: refs/heads/main@{#1043985}
109 lines
3.2 KiB
Markdown
109 lines
3.2 KiB
Markdown
# 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 generates the corresponding Java class, based on a
|
|
template file. The template file must be specified in the GN target.
|
|
|
|
## Usage
|
|
|
|
1. Create a template file (ex. `FooSwitches.java.tmpl`). Change "Copyright
|
|
2020" to be whatever the year is at the time of writing (as you would for any
|
|
other file).
|
|
```java
|
|
// Copyright 2020 The Chromium Authors
|
|
// Use of this source code is governed by a BSD-style license that can be
|
|
// found in the LICENSE file.
|
|
|
|
package org.chromium.foo;
|
|
|
|
// Be sure to escape any curly braces in your template by doubling as
|
|
// follows.
|
|
/**
|
|
* Contains command line switches that are specific to the foo project.
|
|
*/
|
|
public final class FooSwitches {{
|
|
|
|
{NATIVE_STRINGS}
|
|
|
|
// Prevents instantiation.
|
|
private FooSwitches() {{}}
|
|
}}
|
|
```
|
|
|
|
2. Add a new build target and add it to the `srcjar_deps` of an
|
|
`android_library` target:
|
|
|
|
```gn
|
|
if (is_android) {
|
|
import("//build/config/android/rules.gni")
|
|
}
|
|
|
|
if (is_android) {
|
|
java_cpp_strings("java_switches_srcjar") {
|
|
# External code should depend on ":foo_java" instead.
|
|
visibility = [ ":*" ]
|
|
sources = [
|
|
"//base/android/foo_switches.cc",
|
|
]
|
|
template = "//base/android/java_templates/FooSwitches.java.tmpl"
|
|
}
|
|
|
|
# If there's already an android_library target, you can add
|
|
# java_switches_srcjar to that target's srcjar_deps. Otherwise, the best
|
|
# practice is to create a new android_library just for this target.
|
|
android_library("foo_java") {
|
|
srcjar_deps = [ ":java_switches_srcjar" ]
|
|
}
|
|
}
|
|
```
|
|
|
|
3. The generated file `out/Default/gen/.../org/chromium/foo/FooSwitches.java`
|
|
would contain:
|
|
|
|
```java
|
|
// Copyright $YEAR The Chromium Authors
|
|
// Use of this source code is governed by a BSD-style license that can be
|
|
// found in the LICENSE file.
|
|
|
|
package org.chromium.foo;
|
|
|
|
/**
|
|
* Contains command line switches that are specific to the foo project.
|
|
*/
|
|
public final class FooSwitches {
|
|
|
|
// ...snip...
|
|
|
|
// This following string constants were inserted by
|
|
// java_cpp_strings.py
|
|
// From
|
|
// ../../base/android/foo_switches.cc
|
|
// Into
|
|
// ../../base/android/java_templates/FooSwitches.java.tmpl
|
|
|
|
// Documentation for the C++ switch is copied here.
|
|
public static final String SOME_SWITCH = "some-switch";
|
|
|
|
// ...snip...
|
|
|
|
// Prevents instantiation.
|
|
private FooSwitches() {}
|
|
}
|
|
```
|
|
|
|
## See also
|
|
* [Accessing C++ Enums In Java](android_accessing_cpp_enums_in_java.md)
|
|
* [Accessing C++ Features In Java](android_accessing_cpp_features_in_java.md)
|
|
|
|
## Code
|
|
* [Generator
|
|
code](https://cs.chromium.org/chromium/src/build/android/gyp/java_cpp_strings.py?dr=C&sq=package:chromium)
|
|
and
|
|
[Tests](https://cs.chromium.org/chromium/src/build/android/gyp/java_cpp_strings_tests.py?dr=C&sq=package:chromium)
|
|
* [GN
|
|
template](https://cs.chromium.org/chromium/src/build/config/android/rules.gni?sq=package:chromium&dr=C)
|