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Visual Studio Code Dev

Visual Studio Code is a free, lightweight and powerful code editor for Windows, Mac and Linux, based on Electron/Chromium. It has built-in support for JavaScript, TypeScript and Node.js and a rich extension ecosystem that adds intellisense, debugging, syntax highlighting etc. for many languages (C++, Python, Go). It works without too much setup. Get started here.

It is NOT a full-fledged IDE like Visual Studio. The two are completely separate products. The only commonality with Visual Studio is that both are from Microsoft.

Here's what works well:

  • Editing code works well especially when you get used to the keyboard shortcuts. VS Code is very responsive and can handle even big code bases like Chromium.
  • Git integration is a blast. Built-in side-by-side view, local commit and even extensions for history and blame view.
  • Debugging works well, even though startup times can be fairly high (~40 seconds with gdb on Linux, much lower on Windows). You can step through code, inspect variables, view call stacks for multiple threads etc.
  • Opening files and searching solution-wide works well now after having problems in earlier versions.
  • Building works well. Build tools are easy to integrate. Warnings and errors are displayed on a separate page and you can click to jump to the corresponding line of code.

[TOC]

Updating This Page

Please keep this doc up-to-date. VS Code is still in active development and subject to changes. This doc is checked into the Chromium git repo, so if you make changes, read the documentation guidelines and submit a change list.

All file paths and commands have been tested on Linux. Windows and Mac might require a slightly different setup (e.g. Ctrl -> Cmd). Please update this page accordingly.

Setup

Installation

Follow the steps on https://code.visualstudio.com/docs/setup/setup-overview. To run it on Linux, just navigate to chromium/src folder and type code . in a terminal. The argument to code is the base directory of the workspace. VS Code does not require project or solution files. However, it does store workspace settings in a .vscode folder in your base directory.

Useful Extensions

Up to now, you have a basic version of VS Code without much language support. Next, we will install some useful extensions. Jump to the extensions window (Ctrl+Shift+X) and install these extensions, you will most likely use them every day:

  • C/C++ - Code formatting, debugging, Intellisense.
  • Python - Linting, intellisense, code formatting, refactoring, debugging, snippets.
  • Toggle Header/Source - Toggles between .cc and .h with F4. The C/C++ extension supports this as well through Alt+O but sometimes chooses the wrong file when there are multiple files in the workspace that have the same name.
  • Protobuf support - Syntax highlighting for .proto files.
  • you-complete-me - YouCompleteMe code completion for VS Code. It works fairly well in Chromium.
  • Rewrap - Wrap lines at 80 characters with Alt+Q.

To install You-Complete-Me, enter these commands in a terminal:

$ git clone https://github.com/Valloric/ycmd.git ~/.ycmd
$ cd ~/.ycmd
$ git submodule update --init --recursive
$ ./build.py --clang-completer

If it fails with "Your C++ compiler does NOT fully support C++11." but you know you have a good compiler, hack cpp/CMakeLists.txt to set CPP11_AVAILABLE true.

On Mac, replace the last command above with the following.

$ ./build.py --clang-completer --system-libclang

The following extensions might be useful for you as well:

  • Annotator - Git blame view.
  • Git History (git log) - Git history view.
  • chromium-codesearch - Code search (CS) integration, see Chromium Code Search, in particular open current line in CS, show references and go to definition. Very useful for existing code. By design, won't work for code not checked in yet. Overrides default C/C++ functionality. Had some issues last time I tried (extensions stopped working), so use with care.
  • change-case - Quickly change the case of the current selection or current word.
  • Instant Markdown - Instant markdown (.md) preview in your browser as you type. This document was written with this extension!
  • Clang-Format - Format your code using clang-format. The C/C++ extension already supports format-on-save (see C_Cpp.clang_format_formatOnSave setting). This extension adds the ability to format a document or the current selection on demand.

Also be sure to take a look at the VS Code marketplace to check out other useful extensions.

Color Scheme

Press Ctrl+Shift+P, color, Enter to pick a color scheme for the editor. There are also tons of color schemes available for download on the marketplace.

Usage Tips

  • Ctrl+P opens a search box to find and open a file.
  • F1 or Ctrl+Shift+P opens a search box to find a command (e.g. Tasks: Run Task).
  • Ctrl+K, Ctrl+S opens the key bindings editor.
  • Ctrl+` toggles the built-in terminal.
  • Ctrl+Shift+M toggles the problems view (linter warnings, compile errors and warnings). You'll swicth a lot between terminal and problem view during compilation.
  • Alt+O switches between the source/header file.
  • Ctrl+G jumps to a line.
  • F12 jumps to the definition of the symbol at the cursor (also available on right-click context menu).
  • Shift+F12 or F1, CodeSearchReferences, Return shows all references of the symbol at the cursor.
  • F1, CodeSearchOpen, Return opens the current file in Code Search.
  • Ctrl+D selects the word at the cursor. Pressing it multiple times multi-selects the next occurrences, so typing in one types in all of them, and Ctrl+U deselects the last occurrence.
  • Ctrl+K, Z enters Zen Mode, a fullscreen editing mode with nothing but the current editor visible.
  • Ctrl+X without anything selected cuts the current line. Ctrl+V pastes the line.

Setup For Chromium

VS Code is configured via JSON files. This paragraph contains JSON configuration files that are useful for Chromium development, in particular. See VS Code documentation for an introduction to VS Code customization.

Workspace Settings

Open the file chromium/src/.vscode/settings.json and add the following settings. Remember to replace <full_path_to_your_home>!

{
  // Default tab size of 2.
  "editor.tabSize": 2,
  // Do not figure out tab size from opening a file.
  "editor.detectIndentation": false,
  // Add a line at 80 characters.
  "editor.rulers": [80],
  // Optional: Highlight current line at the left of the editor.
  "editor.renderLineHighlight": "gutter",
  // Optional: Don't automatically add closing brackets. It gets in the way.
  "editor.autoClosingBrackets": false,
  // Optional: Enable a tiny 30k feet view of your doc.
  "editor.minimap.enabled": true,
  "editor.minimap.maxColumn": 80,
  "editor.minimap.renderCharacters": false,
  // Trim tailing whitespace on save.
  "files.trimTrailingWhitespace": true,
  // Optional: Do not open files in 'preview' mode. Opening a new file in can
  //           replace an existing one in preview mode, which can be confusing.
  "workbench.editor.enablePreview": false,
  // Optional: Same for files opened from quick open (Ctrl+P).
  "workbench.editor.enablePreviewFromQuickOpen": false,
  // Optional: Don't continuously fetch remote changes.
  "git.autofetch": false,

  "files.associations": {
    // Adds xml syntax highlighting for grd files.
    "*.grd" : "xml",
    // Optional: .gn and .gni are not JavaScript, but at least it gives some
    // approximate syntax highlighting. Ignore the linter warnings!
    "*.gni" : "javascript",
    "*.gn" : "javascript"
  },

  "files.exclude": {
    // Ignore build output folders.
    "out*/**": true
  },

  "files.watcherExclude": {
    // Don't watch out*/ and third_party/ for changes to fix an issue
    // where vscode doesn't notice that files have changed.
    // https://github.com/Microsoft/vscode/issues/3998
    // There is currently another issue that requires a leading **/ for
    // watcherExlude. Beware that this pattern might affect other out* folders
    // like src/cc/output/.
    "**/out*/**": true,
    "**/third_party/**": true
  },

  // Wider author column for annotator extension.
  "annotator.annotationColumnWidth": "24em",

  // C++ clang format settings.
  "C_Cpp.clang_format_path": "${workspaceRoot}/third_party/depot_tools/clang-format",
  "C_Cpp.clang_format_sortIncludes": true,
  "C_Cpp.clang_format_formatOnSave": true,

  // YouCompleteMe
  "ycmd.path": "<full_path_to_your_home>/.ycmd",
  "ycmd.global_extra_config": "${workspaceRoot}/tools/vim/chromium.ycm_extra_conf.py",
  "ycmd.confirm_extra_conf": false,
}

Tasks

Next, we'll tell VS Code how to compile our code and how to read warnings and errors from the build output. Copy the code below to chromium/src/.vscode/tasks.json. This will provide 5 tasks to do basic things. You might have to adjust the commands to your situation and needs.

{
  "version": "0.1.0",
  "runner": "terminal",
  "showOutput": "always",
  "echoCommand": true,
  "tasks": [
  {
    "taskName": "1-build_chrome_debug",
    "command": "ninja -C out/Debug -j 2000 chrome",
    "isShellCommand": true,
    "isTestCommand": true,
    "problemMatcher": [
    {
      "owner": "cpp",
      "fileLocation": ["relative", "${workspaceRoot}"],
      "pattern": {
        "regexp": "^../../(.*):(\\d+):(\\d+):\\s+(warning|\\w*\\s?error):\\s+(.*)$",
        "file": 1, "line": 2, "column": 3, "severity": 4, "message": 5
      }
    },
    {
      "owner": "cpp",
      "fileLocation": ["relative", "${workspaceRoot}"],
      "pattern": {
        "regexp": "^../../(.*?):(.*):\\s+(warning|\\w*\\s?error):\\s+(.*)$",
        "file": 1, "severity": 3, "message": 4
      }
    }]
  },
  {
    "taskName": "2-build_chrome_release",
    "command": "ninja -C out/Release -j 2000 chrome",
    "isShellCommand": true,
    "isBuildCommand": true,
    "problemMatcher": [
    {
      "owner": "cpp",
      "fileLocation": ["relative", "${workspaceRoot}"],
      "pattern": {
        "regexp": "^../../(.*):(\\d+):(\\d+):\\s+(warning|\\w*\\s?error):\\s+(.*)$",
        "file": 1, "line": 2, "column": 3, "severity": 4, "message": 5
      }
    },
    {
      "owner": "cpp",
      "fileLocation": ["relative", "${workspaceRoot}"],
      "pattern": {
        "regexp": "^../../(.*?):(.*):\\s+(warning|\\w*\\s?error):\\s+(.*)$",
        "file": 1, "severity": 3, "message": 4
      }
    }]
  },
  {
    "taskName": "3-build_all_debug",
    "command": "ninja -C out/Debug -j 2000",
    "isShellCommand": true,
    "problemMatcher": [
    {
      "owner": "cpp",
      "fileLocation": ["relative", "${workspaceRoot}"],
      "pattern": {
        "regexp": "^../../(.*):(\\d+):(\\d+):\\s+(warning|\\w*\\s?error):\\s+(.*)$",
        "file": 1, "line": 2, "column": 3, "severity": 4, "message": 5
      }
    },
    {
      "owner": "cpp",
      "fileLocation": ["relative", "${workspaceRoot}"],
      "pattern": {
        "regexp": "^../../(.*?):(.*):\\s+(warning|\\w*\\s?error):\\s+(.*)$",
        "file": 1, "severity": 3, "message": 4
      }
    }]
  },
  {
    "taskName": "4-build_all_release",
    "command": "ninja -C out/Release -j 2000",
    "isShellCommand": true,
    "problemMatcher": [
    {
      "owner": "cpp",
      "fileLocation": ["relative", "${workspaceRoot}"],
      "pattern": {
        "regexp": "^../../(.*):(\\d+):(\\d+):\\s+(warning|\\w*\\s?error):\\s+(.*)$",
        "file": 1, "line": 2, "column": 3, "severity": 4, "message": 5
      }
    },
    {
      "owner": "cpp",
      "fileLocation": ["relative", "${workspaceRoot}"],
      "pattern": {
        "regexp": "^../../(.*?):(.*):\\s+(warning|\\w*\\s?error):\\s+(.*)$",
        "file": 1, "severity": 3, "message": 4
      }
    }]
  },
  {
    "taskName": "5-build_test_debug",
    "command": "ninja -C out/Debug -j 2000 unit_tests components_unittests browser_tests",
    "isShellCommand": true,
    "problemMatcher": [
    {
      "owner": "cpp",
      "fileLocation": ["relative", "${workspaceRoot}"],
      "pattern": {
        "regexp": "^../../(.*):(\\d+):(\\d+):\\s+(warning|\\w*\\s?error):\\s+(.*)$",
        "file": 1, "line": 2, "column": 3, "severity": 4, "message": 5
      }
    },
    {
      "owner": "cpp",
      "fileLocation": ["relative", "${workspaceRoot}"],
      "pattern": {
        "regexp": "^../../(.*?):(.*):\\s+(warning|\\w*\\s?error):\\s+(.*)$",
        "file": 1, "severity": 3, "message": 4
      }
    }]
  },
  {
    "taskName": "6-build_current_file",
    "command": "compile_single_file --build-dir=out/Debug --file-path=${file}",
    "isShellCommand": true,
    "problemMatcher": [
    {
      "owner": "cpp",
      "fileLocation": ["relative", "${workspaceRoot}"],
      "pattern": {
        "regexp": "^../../(.*):(\\d+):(\\d+):\\s+(warning|\\w*\\s?error):\\s+(.*)$",
        "file": 1, "line": 2, "column": 3, "severity": 4, "message": 5
      }
    },
    {
      "owner": "cpp",
      "fileLocation": ["relative", "${workspaceRoot}"],
      "pattern": {
        "regexp": "^../../(.*?):(.*):\\s+(warning|\\w*\\s?error):\\s+(.*)$",
        "file": 1, "severity": 3, "message": 4
      }
    }]
  }]
}

Launch Commands

Launch commands are the equivalent of F5 in Visual Studio: They launch some program or a debugger. Optionally, they can run some task defined in tasks.json. Launch commands can be run from the debug view (Ctrl+Shift+D). Copy the code below to chromium/src/.vscode/launch.json and adjust them to your situation and needs.

{
  "version": "0.2.0",
  "configurations": [
  {
    "name": "Chrome Debug",
    "type": "cppdbg",
    "request": "launch",
    "targetArchitecture": "x64",
    "program": "${workspaceRoot}/out/Debug/chrome",
    "args": [],  // Optional command line args
    "preLaunchTask": "1-build_chrome_debug",
    "stopAtEntry": false,
    "cwd": "${workspaceRoot}/out/Debug/",
    "environment": [],
    "externalConsole": true
  },
  {
    "name": "Chrome Release",
    "type": "cppdbg",
    "request": "launch",
    "targetArchitecture": "x64",
    "program": "${workspaceRoot}/out/Release/chrome",
    "args": [],  // Optional command line args
    "preLaunchTask": "2-build_chrome_release",
    "stopAtEntry": false,
    "cwd": "${workspaceRoot}/out/Release/",
    "environment": [],
    "externalConsole": true
  },
  {
    "name": "Custom Test Debug",
    "type": "cppdbg",
    "request": "launch",
    "targetArchitecture": "x64",
    "program": "${workspaceRoot}/out/Debug/unit_tests",
    "args": ["--gtest_filter=*",
              "--single_process",
              "--ui-test-action-max-timeout=1000000",
              "--test-launcher-timeout=1000000"],
    "preLaunchTask": "5-build_test_debug",
    "stopAtEntry": false,
    "cwd": "${workspaceRoot}/out/Debug/",
    "environment": [],
    "externalConsole": true
  },
  {
    "name": "Attach Debug",
    "type": "cppdbg",
    "request": "launch",
    "targetArchitecture": "x64",
    "program": "${workspaceRoot}/out/Debug/chrome",
    "args": ["--remote-debugging-port=2224"],
    "stopAtEntry": false,
    "cwd": "${workspaceRoot}/out/Debug/",
    "environment": [],
    "externalConsole": false
  }]
}

Key Bindings

To edit key bindings, press Ctrl+K, Ctrl+S. You'll see the defaults on the left and your overrides on the right stored in the file keybindings.json. To change a key binding, copy the corresponding key binding to the right. It's fairly self-explanatory.

You can bind any command to a key, even commands specified by extensions like CodeSearchOpen. For instance, to bind CodeSearchOpen to F2 to , simply add { "key": "F2", "command": "cs.open" },. Note that the command title CodeSearchOpen won't work. You have to get the actual command name from the package.json file of the extension.

If you are used to other editors, you can also install your favorite keymap. For instance, to install eclipse keymaps, install the vscode-eclipse-keybindings extension. More keymaps can be found in the marketplace.

Here are some key bindings that are likely to be useful for you:

// Place your key bindings in this file to overwrite the defaults
[
// Run the task marked as "isTestCommand": true, see tasks.json.
{ "key": "ctrl+shift+t",       "command": "workbench.action.tasks.test" },
// Jump to the previous change in the built-in diff tool.
{ "key": "ctrl+up",            "command": "workbench.action.compareEditor.previousChange" },
// Jump to the next change in the built-in diff tool.
{ "key": "ctrl+down",          "command": "workbench.action.compareEditor.nextChange" },
// Jump to previous location in the editor (useful to get back from viewing a symbol definition).
{ "key": "alt+left",           "command": "workbench.action.navigateBack" },
// Jump to next location in the editor.
{ "key": "alt+right",          "command": "workbench.action.navigateForward" },
// Get a blame view of the current file. Requires the annotator extension.
{ "key": "ctrl+alt+a",         "command": "annotator.annotate" },
// Toggle header/source with the Toggle Header/Source extension (overrides the
// key binding from the C/C++ extension as I found it to be slow).
{ "key": "alt+o",              "command": "togglehs.toggleHS" },
// Quickly run a task, see tasks.json. Since we named them 1-, 2- etc., it is
// suffucient to press the corresponding number.
{ "key": "ctrl+r",             "command": "workbench.action.tasks.runTask",
                                  "when": "!inDebugMode" },
// The following keybindings are useful on laptops with small keyboards such as
// Chromebooks that don't provide all keys.
{ "key": "shift+alt+down",     "command": "cursorColumnSelectDown",
                                  "when": "editorTextFocus" },
{ "key": "shift+alt+left",     "command": "cursorColumnSelectLeft",
                                  "when": "editorTextFocus" },
{ "key": "shift+alt+pagedown", "command": "cursorColumnSelectPageDown",
                                  "when": "editorTextFocus" },
{ "key": "shift+alt+pageup",   "command": "cursorColumnSelectPageUp",
                                  "when": "editorTextFocus" },
{ "key": "shift+alt+right",    "command": "cursorColumnSelectRight",
                                  "when": "editorTextFocus" },
{ "key": "shift+alt+up",       "command": "cursorColumnSelectUp",
                                  "when": "editorTextFocus" },
{ "key": "alt+down",           "command": "scrollPageDown",
                                  "when": "editorTextFocus" },
{ "key": "alt+up",             "command": "scrollPageUp",
                                  "when": "editorTextFocus" },
{ "key": "alt+backspace",      "command": "deleteRight",
                                  "when": "editorTextFocus && !editorReadonly" },
{ "key": "ctrl+right",         "command": "cursorEnd",
                                  "when": "editorTextFocus" },
{ "key": "ctrl+shift+right",   "command": "cursorEndSelect",
                                  "when": "editorTextFocus" },
{ "key": "ctrl+left",          "command": "cursorHome",
                                  "when": "editorTextFocus" },
{ "key": "ctrl+shift+left",    "command": "cursorHomeSelect",
                                  "when": "editorTextFocus" },
]

Tips

The out folder

Automatically generated code is put into a subfolder of out/, which means that these files are ignored by VS Code (see files.exclude above) and cannot be opened e.g. from quick-open (Ctrl+P). As of version 1.21, VS Code does not support negated glob commands, but you can define a set of exclude pattern to include only out/Debug/gen:

"files.exclude": {
  // Ignore build output folders. Except out/Debug/gen/
  "out/[^D]*/": true,
  "out/Debug/[^g]*": true,
  "out/Debug/g[^e]*": true,
  "out_*/**": true,
},

Once it does, you can use

"!out/Debug/gen/**": true

in files.exclude instead of the symlink.

Using VS Code as git editor

Add [core] editor = "code --wait" to your ~/.gitconfig file in order to use VS Code as editor for git commit messages etc. Note that the editor starts up significantly slower than nano or vim. To use VS Code as merge tool, add [merge] tool = code.

Task Names

Note that we named the tasks 1-build_chrome_debug, 2-build_chrome_release etc. This allows you to quickly execute tasks by pressing their number: Press Ctrl+P and enter task <n>, where <n> is the number of the task. You can also create a keyboard shortcut for running a task. File > Preferences > Keyboard Shortcuts and add { "key": "ctrl+r", "command": "workbench.action.tasks.runTask", "when": "!inDebugMode" }. Then it's sufficient to press Ctrl+R and enter <n>.

Working on Laptop

Because autocomplete is provided by the You-Complete-Me extension, consider disabling C/C++ autocomplete and indexing to save battery. In addition, you might want to disable git status autorefresh as well.

"git.autorefresh": false,
"C_Cpp.autocomplete": "Disabled",
"C_Cpp.addWorkspaceRootToIncludePath": false

Unable to open $File resource is not available when debugging Chromium on Linux

Chromium recently changed the file path to be relative to the output dir. Check gn args out/$dir --list if strip_absolute_paths_from_debug_symbols is true (which is the default), set cwd to the output dir. otherwise, set cwd to ${workspaceRoot}.

More

More tips and tricks can be found here.