Webrtc native M96 version opening trip -- a reading code download and compilation (Ninja GN depot_tools)

Welcome to the bitter WebRTC download 、 Compile the world .

depot_tools

depot_tools It's a toolkit （depot Warehouse means ）, It contains gclient、gcl、gn and ninja Tools such as , These tools are all used python Written . Its main function is to git The enhancement of , Make code management and compilation easier , The premise of learning this is to be able to use git.

obtain DEPOT TOOLS
LINUX / MAC System ：

git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git
export PATH=/path/to/depot_tools:$PATH

WINDOWS System ：

https://storage.googleapis.com/chrome-infra/depot_tools.zip

Add to system environment variable , for example ：

C:\depot_tools

After decompression , stay cmd In the implementation of gclient command , Download some windows Specific software and libraries . Such as git And python
If appear fail, It's going to continue gclient

depot_tools function gclient The tool will be updated automatically . To disable automatic updates , Please set environment variable DEPOT_TOOLS_UPDATE=0

To configure git

Omit , If you haven't used it git, Then you don't deserve to play WebRTC

visit Google

Do this by yourself ！

Visual Studio 2019 as well as Windowns 10 SDK

Personal Edition Community version is ok , Install everything you can

Configure environment variables

Permanent variables – Set to the system environment variable ：

DEPOT_TOOLS_WIN_TOOLCHAIN=0
GYP_MSVS_VERSION=2019
WINDOWSSDKDIR=C:\Program Files (x86)\Windows Kits\10\
GYP_MSVS_OVERRIDE_PATH=C:\Program Files (x86)\Microsoft Visual Studio\2019\Community

Temporary variable – Every time you execute

set DEPOT_TOOLS_WIN_TOOLCHAIN=0
set GYP_MSVS_VERSION=2019
set WINDOWSSDKDIR=C:\Program Files (x86)\Windows Kits\10\
set GYP_MSVS_OVERRIDE_PATH=C:\Program Files (x86)\Microsoft Visual Studio\2019\Community

set DEPOT_TOOLS_WIN_TOOLCHAIN=0
tell depot_tools Use our native VS Compile

Download the source code

Find a disk with large space , Catalog

mkdir webrtc-m96
cd webrtc-m96
fetch --nohooks webrtc
gclient sync

Then there is the long wait , There are many things to be done .
If it is interrupted due to network and other reasons , Don't panic. ：
We'll do it again

gclient sync

If it gets stuck , Don't panic. ：

ctrl+c
gclient sync.

After downloading successfully , Switch branches m96

git checkout branch-heads/4664
gclient sync -D

Generate sln Solution

cd src
gn gen --ide=vs out\Default

Compile code

A command line compilation ：

ninja -C out/Default
ninja

A kind of vs2019 compile ：
Omit
There will be some mistakes , Some project generation compilation failed , But it doesn't matter ,example It can be used normally .

Common mistakes

Exception: No supported Visual Studio can be found. Supported versions are: 16.0 (2019), 15.0 (2017).
ERROR at //build/config/win/visual_studio_version.gni:27:7: Script returned non-zero exit code.
exec_script("…/…/vs_toolchain.py", [ “get_toolchain_dir” ], “scope”)

This is because python Script is looking for vs There is an error in the installation path of , The default is C Disk to find , But if vs2019 Not installed in C disc , That would have to be revised vs_toolchain.py This file , route src/build, The original code is as follows , Probably 176 That's ok ：

path = os.path.expandvars('D:/Program Files (x86)/Microsoft Visual Studio/%s' % version)

os.path.expandvars('D:\Program Files (x86)\Microsoft Visual Studio/%s/Community' %version_as_year),

gn Ninja Introduce

Ninja It's the excuse Google Chrome A construction tool born out of the project , It was born for speed .

gn It solves the problem of cross platform compilation , But the code editing of each platform , It doesn't belong to the bottom C++ Scope of cross platform construction tools （ Whole frame C++ Process Qt exception ）. One way is to , adopt gn Generate projects for each platform （xcode engineering 、vs engineering ） Then code , The modification of source files and engineering modules needs to be synchronized to gn In engineering documents ; Another way is to use vscode.

gn Documentation ：

executable("hello") {
sources = [ "hello.cc" ]

deps = [
":hello_shared",
":hello_static",
]
}

shared_library("hello_shared") {
sources = [
"hello_shared.cc",
"hello_shared.h",
]

defines = [ "HELLO_SHARED_IMPLEMENTATION" ]
}

static_library("hello_static") {
sources = [
"hello_static.cc",
"hello_static.h",
]
}