| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 1 | # Emacs |
| 2 | |
| 3 | [TOC] |
| 4 | |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 5 | ## Debugging |
| 6 | |
| Tom Anderson | 93e49e49 | 2019-12-23 19:55:37 | [diff] [blame] | 7 | [LinuxDebugging](linux/debugging.md) has someEmacs-specific debugging tips. |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 8 | |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 9 | ## Syntax-error Highlighting |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 10 | |
| 11 | [Ninja](ninja_build.md) usersgetin-line highlighting of syntax errorsusing |
| 12 | `flymake.el` on each buffer-save: |
| 13 | |
| 14 | |
| 15 | (load-file"src/tools/emacs/flymake-chromium.el") |
| 16 | |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 17 | ## [ycmd](https://github.com/Valloric/ycmd) (YouCompleteMe) + flycheck |
| 18 | |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 19 | [emacs-ycmd](https://github.com/abingham/emacs-ycmd) in combination with |
| 20 | flycheck provides: |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 21 | |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 22 | * advanced code completion |
| 23 | * syntax checking |
| 24 | * navigation to declarationsand definitions(using`ycmd-goto`) based on |
| 25 | on-the-fly processingusing clang. A quick demo video showing code |
| 26 | completionand flycheck highlighting a missing semicolon syntax error: |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 27 | |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 28 | [![video preview][img]][video] |
| 29 | |
| 30 | [img]: http://img.youtube.com/vi/a0zMbm4jACk/0.jpg |
| 31 | [video]: http://www.youtube.com/watch?feature=player_embedded&v=a0zMbm4jACk |
| 32 | |
| 33 | ### Requirements |
| 34 | |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 35 | *Your build systemisset upfor buildingwith clangor wrapper+clang |
| 36 | |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 37 | ### Setup |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 38 | |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 39 | 1.Clone, update external git repositoriesand build.sh ycmdfrom |
| Benoit Lize | e27b674 | 2020-07-30 14:43:15 | [diff] [blame] | 40 | https://github.com/ycm-core/YouCompleteMe into a directory, e.g. `~/dev/ycmd` |
| 41 | *The ycmd packaging changed, the serverisin a different location.To |
| 42 | build it, run: |
| 43 | ```shell |
| 44 | cd ~/dev/ycmd |
| 45 | git submodule update --init --recursive |
| 46 | python3 install.py --clang-completer |
| 47 | ``` |
| 48 | 1.Test`ycmd`by running`~/dev/ycmd$ python third_party/ycmd/__main__.py --options_file /tmp/test.json`.The options file can be createdwith e.g.`echo '{"hmac_secret": "1234567812345678"}' > /tmp/test.json`.The server should start normally. |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 49 | 1.Install the following packages to emacs,for examplefrom melpa: |
| 50 | *`ycmd` |
| 51 | *`company-ycmd` |
| 52 | *`flycheck-ycmd` |
| 53 | 1.[More info on configuring emacs-ycmd](https://github.com/abingham/emacs-ycmd#quickstart) |
| 54 | 1.Assuming your checkout ofChromiumisin`~/dev/blink`, i.e.thisis the |
| 55 | directoryin which you find the`src`folder, create a symbolic linkas |
| 56 | follows: |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 57 | |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 58 | ```shell |
| 59 | cd ~/dev/blink |
| 60 | ln -s src/tools/vim/chromium.ycm_extra_conf.py .ycm_extra_conf.py |
| 61 | ``` |
| 62 | |
| 63 | 1.Add something like the following to your`init.el` |
| 64 | |
| 65 | ```el |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 66 | ;; ycmd |
| 67 | |
| 68 | ;;; Googlers can replace a lot of this with (require 'google-ycmd). |
| 69 | |
| 70 | (require 'ycmd) |
| 71 | (require 'company-ycmd) |
| 72 | (require 'flycheck-ycmd) |
| 73 | |
| 74 | (company-ycmd-setup) |
| 75 | (flycheck-ycmd-setup) |
| 76 | |
| 77 | ;; Show completions after 0.15 seconds |
| 78 | (setq company-idle-delay 0.15) |
| 79 | |
| 80 | ;; Activate for editing C++ files |
| 81 | (add-hook 'c++-mode-hook 'ycmd-mode) |
| 82 | (add-hook 'c++-mode-hook 'company-mode) |
| 83 | (add-hook 'c++-mode-hook 'flycheck-mode) |
| 84 | |
| 85 | ;; Replace the directory information with where you downloaded ycmd to |
| Benoit Lize | e27b674 | 2020-07-30 14:43:15 | [diff] [blame] | 86 | (set-variable 'ycmd-server-command (list "python3" (substitute-in-file-name "$HOME/dev/ycmd/third_party/ycmd/ycmd/__main__.py"))) |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 87 | |
| 88 | ;; Edit according to where you have your Chromium/Blink checkout |
| 89 | (add-to-list 'ycmd-extra-conf-whitelist (substitute-in-file-name "$HOME/dev/blink/.ycm_extra_conf.py")) |
| 90 | |
| 91 | ;; Show flycheck errors in idle-mode as well |
| 92 | (setq ycmd-parse-conditions '(save new-line mode-enabled idle-change)) |
| 93 | |
| 94 | ;; Makes emacs-ycmd less verbose |
| 95 | (setq url-show-status nil) |
| 96 | ``` |
| 97 | |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 98 | ### Troubleshooting |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 99 | |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 100 | *Ifno completions show upor emacs reports errors, you can check the |
| 101 | `*ycmd-server*` bufferfor errors.See thenext bullet pointfor how to |
| 102 | handle"OS Error: No such file or directory" |
| 103 | *Launching emacsfrom an OS menu might resultin a different environment so |
| 104 | that`ycmd` doesnot find ninja.In thatcase, you canuse apackage like |
| 105 | [exec-pathfrom shell](https://github.com/purcell/exec-path-from-shell) and |
| 106 | add the following to your`init.el`: |
| 107 | |
| 108 | ```el |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 109 | (require 'exec-path-from-shell) |
| 110 | (when (memq window-system '(mac ns x)) |
| 111 | (exec-path-from-shell-initialize)) |
| 112 | ``` |
| Benoit Lize | e27b674 | 2020-07-30 14:43:15 | [diff] [blame] | 113 | * ycmd depends on the installed version of python.For googlers running gLinux, |
| 114 | a system update may have changed the python version.Inthiscase, you need to |
| 115 | recompile ycmd first. |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 116 | |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 117 | ## ff-get-other-file |
| 118 | |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 119 | There's a builtin function called `ff-get-other-file` which will get the "other |
| 120 | file" based on file extension. I have this bound to C-o in c-mode |
| 121 | (`(local-set-key "\C-o" 'ff-get-other-file)`). While "other file" is per-mode |
| 122 | defined, in c-like languages it means jumping between the header and the source |
| 123 | file. So I switch back and forth between the header and the source with C-o. If |
| 124 | we had separate include/ and src/ directories, this would be a pain to setup, |
| 125 | but this might just work out of the box for you. See the documentation for the |
| 126 | variable `cc-other-file-alist` for more information. |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 127 | |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 128 | One drawback of ff-get-other-file is that it will always switch to a matching |
| 129 | buffer, even if the other file is in a different directory, so if you have |
| 130 | A.cc,A.h,A.cc(2) then ff-get-other-file will switch to A.h from A.cc(2) rather |
| 131 | than load A.h(2) from the appropriate directory. If you prefer something (C |
| 132 | specific) that always finds, try this: |
| 133 | |
| 134 | ```el |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 135 | (defun cc-other-file() |
| 136 | "Toggles source/header file" |
| 137 | (interactive) |
| 138 | (let((buf(current-buffer)) |
| 139 | (name(file-name-sans-extension(buffer-file-name))) |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 140 | (other-extens |
| 141 | (cadr(assoc(concat"\\." |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 142 | (file-name-extension(buffer-file-name)) |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 143 | "\\'") |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 144 | cc-other-file-alist)))) |
| 145 | (dolist(e other-extens) |
| 146 | (if(let((f(concat name e))) |
| 147 | (and(file-exists-p f)(find-file f))) |
| 148 | (return))) |
| 149 | ) |
| 150 | ) |
| 151 | ``` |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 152 | |
| 153 | _Note: if you know an easy way to change the ff-get-other-file behavior, please |
| 154 | replace this hack with that solution! - stevenjb@chromium.org_ |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 155 | |
| 156 | ## Use Google's C++ style! |
| 157 | |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 158 | We have an emacs module, |
| 159 | [google-c-style.el](http://google-styleguide.googlecode.com/svn/trunk/google-c-style.el), |
| 160 | which adds c-mode formatting. Then add to your .emacs: |
| 161 | |
| 162 | ```el |
| Joanna Wang | 3aafdb2 | 2023-05-26 15:03:31 | [diff] [blame] | 163 | (load"/<path/to/chromium>/src/third_party/clang-format/script/clang-format.el") |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 164 | (add-hook'c-mode-common-hook |
| 165 | (function (lambda () (local-set-key (kbd "TAB") 'clang-format-region)))) |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 166 | ``` |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 167 | |
| 168 | Now, you can use the |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 169 | |
| 170 | <Tab> |
| 171 | |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 172 | key to format the current line (even a long line) or region. |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 173 | |
| Daniel Bratell | ad5d099 | 2018-09-21 16:35:18 | [diff] [blame] | 174 | ## BUILD.gn and .gni files |
| 175 | |
| 176 | BUILD.gn and gni files are supported by the official gn-mode which can |
| 177 | be enabled with: |
| 178 | |
| 179 | (load-file "src/tools/emacs/gn.el") |
| 180 | |
| Dan McArdle | 50bc621f0 | 2023-11-29 10:32:30 | [diff] [blame] | 181 | ## Mojom IDL (.mojom files) |
| 182 | |
| 183 | [Mojom](/mojo/public/tools/bindings/README.md) |
| 184 | files are supported by mojom-mode, which can be enabled with: |
| 185 | |
| 186 | ```el |
| 187 | (load-file"/<path/to/chromium>/src/tools/emacs/mojom-mode.el") |
| 188 | ``` |
| 189 | |
| 190 | Alternatively, you can `require` the feature. |
| 191 | (See emacs documentation on |
| 192 | [Named Features](https://www.gnu.org/software/emacs/manual/html_node/elisp/Named-Features.html).) |
| 193 | |
| 194 | ```el |
| 195 | (add-to-list'load-path "/<path/to/chromium>/src/tools/emacs/") |
| 196 | (require 'mojom-mode) |
| 197 | ``` |
| 198 | |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 199 | ## Highlight long lines |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 200 | |
| 201 | One nice way to highlight long lines and other style issues: |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 202 | |
| 203 | ```el |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 204 | (require'whitespace) |
| 205 | (setq whitespace-style '(face indentation trailing empty lines-tail)) |
| 206 | (setq whitespace-line-columnnil) |
| 207 | (set-face-attribute'whitespace-line nil |
| 208 | :background "purple" |
| 209 | :foreground "white" |
| 210 | :weight 'bold) |
| 211 | (global-whitespace-mode1) |
| 212 | ``` |
| 213 | |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 214 | Note: You might need to grab the latest version of |
| 215 | [whitespace.el](http://www.emacswiki.org/emacs-en/download/whitespace.el). |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 216 | |
| Daniel Bratell | f73f0df | 2018-09-24 13:52:49 | [diff] [blame] | 217 | ## deep nesting |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 218 | |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 219 | A couple of helpers that show a summary of where you are; the first by tracing |
| 220 | the indentation hierarchy upwards, the second by only showing `#if`s and |
| 221 | `#else`s that are relevant to the current line: |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 222 | |
| 223 | ```el |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 224 | (defun ami-summarize-indentation-at-point () |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 225 | "Echo a summary of how one gets from the left-most column to |
| 226 | POINT in terms of indentation changes." |
| 227 | (interactive) |
| 228 | (save-excursion |
| 229 | (let ((cur-indent most-positive-fixnum) |
| 230 | (trace '())) |
| 231 | (while (not (bobp)) |
| 232 | (let ((current-line (buffer-substring (line-beginning-position) |
| 233 | (line-end-position)))) |
| 234 | (when (and (not (string-match "^\\s-*$" current-line)) |
| 235 | (< (current-indentation) cur-indent)) |
| 236 | (setq cur-indent (current-indentation)) |
| 237 | (setq trace (cons current-line trace)) |
| 238 | (if (or (string-match "^\\s-*}" current-line) |
| 239 | (string-match "^\\s-*else " current-line) |
| 240 | (string-match "^\\s-*elif " current-line)) |
| 241 | (setq cur-indent (1+ cur-indent))))) |
| 242 | (forward-line -1)) |
| 243 | (message "%s" (mapconcat 'identity trace "\n"))))) |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 244 | |
| 245 | (require 'cl) |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 246 | (defun ami-summarize-preprocessor-branches-at-point () |
| 247 | "Summarize the C preprocessor branches needed to get to point." |
| 248 | (interactive) |
| 249 | (flet ((current-line-text () |
| 250 | (buffer-substring (line-beginning-position) (line-end-position)))) |
| 251 | (save-excursion |
| 252 | (let ((eol (or (end-of-line) (point))) |
| 253 | deactivate-mark directives-stack) |
| 254 | (goto-char (point-min)) |
| 255 | (while (re-search-forward "^#\\(if\\|else\\|endif\\)" eol t) |
| 256 | (if (or (string-prefix-p "#if" (match-string 0)) |
| 257 | (string-prefix-p "#else" (match-string 0))) |
| 258 | (push (current-line-text) directives-stack) |
| 259 | (if (string-prefix-p "#endif" (match-string 0)) |
| 260 | (while (string-prefix-p "#else" (pop directives-stack)) t)))) |
| 261 | (message "%s" (mapconcat 'identity (reverse directives-stack) "\n")))))) |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 262 | ``` |
| 263 | |
| 264 | ## find-things-fast |
| 265 | |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 266 | erg wrote a suite of tools thatdo common operationsfrom the root of your |
| 267 | repository, called |
| 268 | [FindThingsFast](https://github.com/eglaysher/find-things-fast). It contains |
| 269 | ido completion over`git ls-files`(or the svn find equivalent)and`grepsource` |
| 270 | that only git greps fileswith extensions we care about(or the equivalent the |
| 271 | `find | xargs grep` statementin non-git repos.) |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 272 | |
| 273 | ## vc-mode and find-file performance |
| 274 | |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 275 | When you first open a file under git control, vc mode kicksinand does a high |
| 276 | level stat of your git repo.For huge repos, especiallyWebKitandChromium, |
| 277 | this makes opening a file take literally seconds.This snippet disables VC git |
| 278 | for chrome directories: |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 279 | |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 280 | ```el |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 281 | ; Turn off VC git for chrome |
| 282 | (when (locate-library "vc") |
| 283 | (defadvice vc-registered (around nochrome-vc-registered (file)) |
| 284 | (message (format "nochrome-vc-registered %s" file)) |
| 285 | (if (string-match ".*chrome/src.*" file) |
| 286 | (progn |
| 287 | (message (format "Skipping VC mode for %s" % file)) |
| 288 | (setq ad-return-value nil) |
| 289 | ) |
| 290 | ad-do-it) |
| 291 | ) |
| 292 | (ad-activate 'vc-registered) |
| 293 | ) |
| 294 | ``` |
| 295 | |
| 296 | ## git tools |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 297 | |
| andybons | 22afb31 | 2015-08-31 02:24:51 | [diff] [blame] | 298 | We're collecting Chrome-specific tools under `tools/emacs`. See the files there |
| 299 | for details. |
| 300 | |
| 301 | * `trybot.el`: import Windows trybot output into a `compilation-mode` buffer. |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 302 | |
| 303 | ## ERC for IRC |
| 304 | |
| asargent | 4adb811 | 2015-12-07 19:42:02 | [diff] [blame] | 305 | See [ErcIrc](erc_irc.md). |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 306 | |
| Junichi Uekawa | 75d91cad | 2021-06-15 05:54:42 | [diff] [blame] | 307 | ## Compilation with M-x compile |
| andybons | 3322f76 | 2015-08-24 21:37:09 | [diff] [blame] | 308 | |
| Junichi Uekawa | 75d91cad | 2021-06-15 05:54:42 | [diff] [blame] | 309 | It's usually useful to first find the top directorywith locate-dominating-file, |
| 310 | and run`M-x compile` |
| 311 | |
| 312 | ```lisp |
| 313 | (defun chromium-compile () |
| 314 | "Run compile for chromium." |
| 315 | (interactive) |
| 316 | (let ((chrome-dir (locate-dominating-file "." "chrome/BUILD.gn"))) |
| 317 | (when chrome-dir |
| 318 | (let* ((default-directory chrome-dir)) |
| 319 | (compile "ninja -C out/Debug chrome chrome_sandbox "))))) |
| 320 | ``` |
