Add IPC config subcommand

This patch adds a new mechanism for changing configuration options
without editing the configuration file, by sending options to running
instances through `alacritty msg`.

Each window will load Alacritty's configuration file by default and then
accept IPC messages for config updates using the `alacritty msg config`
subcommand. By default all windows will be updated, individual windows
can be addressed using `alacritty msg config --window-id
"$ALACRITTY_WINDOW_ID"`.

Each option will replace the config's current value and cannot be reset
until Alacritty is restarted or the option is overwritten with a new
value.

Configuration options are passed in the format `field.subfield=value`,
where `value` is interpreted as yaml.

Closes #472.

3 files changed, 51 insertions, 5 deletions

diff --git a/extra/completions/_alacritty b/extra/completions/_alacritty
index 50a5c00d..6b80a797 100644
--- a/extra/completions/_alacritty
+++ b/extra/completions/_alacritty
@@ -73,6 +73,17 @@ _arguments "${_arguments_options[@]}" \
 '--help[Print help information]' \
 && ret=0
 ;;
+(config)
+_arguments "${_arguments_options[@]}" \
+'-w+[Window ID for the new config]:WINDOW_ID: ' \
+'--window-id=[Window ID for the new config]:WINDOW_ID: ' \
+'()-r[Clear all runtime configuration changes]' \
+'()--reset[Clear all runtime configuration changes]' \
+'-h[Print help information]' \
+'--help[Print help information]' \
+'*::options -- Configuration file options \[example\: cursor.style=Beam\]:' \
+&& ret=0
+;;
 (help)
 _arguments "${_arguments_options[@]}" \
 '*::subcommand -- The subcommand whose help message to display:' \
@@ -100,6 +111,11 @@ _alacritty_commands() {
     )
     _describe -t commands 'alacritty commands' commands "$@"
 }
+(( $+functions[_alacritty__msg__config_commands] )) ||
+_alacritty__msg__config_commands() {
+    local commands; commands=()
+    _describe -t commands 'alacritty msg config commands' commands "$@"
+}
 (( $+functions[_alacritty__msg__create-window_commands] )) ||
 _alacritty__msg__create-window_commands() {
     local commands; commands=()
@@ -119,6 +135,7 @@ _alacritty__msg__help_commands() {
 _alacritty__msg_commands() {
     local commands; commands=(
 'create-window:Create a new window in the same Alacritty process' \
+'config:Update the Alacritty configuration' \
 'help:Print this message or the help of the given subcommand(s)' \
     )
     _describe -t commands 'alacritty msg commands' commands "$@"
diff --git a/extra/completions/alacritty.bash b/extra/completions/alacritty.bash
index 428e9583..5cca6466 100644
--- a/extra/completions/alacritty.bash
+++ b/extra/completions/alacritty.bash
@@ -12,6 +12,9 @@ _alacritty() {
             "$1")
                 cmd="alacritty"
                 ;;
+            config)
+                cmd+="__config"
+                ;;
             create-window)
                 cmd+="__create__window"
                 ;;
@@ -100,7 +103,7 @@ _alacritty() {
             return 0
             ;;
         alacritty__msg)
-            opts="-s -h --socket --help create-window help"
+            opts="-s -h --socket --help create-window config help"
             if [[ ${cur} == -* || ${COMP_CWORD} -eq 2 ]] ; then
                 COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
                 return 0
@@ -121,6 +124,28 @@ _alacritty() {
             COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
             return 0
             ;;
+        alacritty__msg__config)
+            opts="-w -r -h --window-id --reset --help <CONFIG_OPTIONS>..."
+            if [[ ${cur} == -* || ${COMP_CWORD} -eq 3 ]] ; then
+                COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
+                return 0
+            fi
+            case "${prev}" in
+                --window-id)
+                    COMPREPLY=($(compgen -f "${cur}"))
+                    return 0
+                    ;;
+                -w)
+                    COMPREPLY=($(compgen -f "${cur}"))
+                    return 0
+                    ;;
+                *)
+                    COMPREPLY=()
+                    ;;
+            esac
+            COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
+            return 0
+            ;;
         alacritty__msg__create__window)
             opts="-e -t -h --working-directory --hold --command --title --class --help"
             if [[ ${cur} == -* || ${COMP_CWORD} -eq 3 ]] ; then
diff --git a/extra/completions/alacritty.fish b/extra/completions/alacritty.fish
index 69b3d777..fdc24ab2 100644
--- a/extra/completions/alacritty.fish
+++ b/extra/completions/alacritty.fish
@@ -15,13 +15,17 @@ complete -c alacritty -n "__fish_use_subcommand" -s v -d 'Increases the level of
 complete -c alacritty -n "__fish_use_subcommand" -l hold -d 'Remain open after child process exit'
 complete -c alacritty -n "__fish_use_subcommand" -f -a "msg" -d 'Send a message to the Alacritty socket'
 complete -c alacritty -n "__fish_use_subcommand" -f -a "help" -d 'Print this message or the help of the given subcommand(s)'
-complete -c alacritty -n "__fish_seen_subcommand_from msg; and not __fish_seen_subcommand_from create-window; and not __fish_seen_subcommand_from help" -s s -l socket -d 'IPC socket connection path override' -r -F
-complete -c alacritty -n "__fish_seen_subcommand_from msg; and not __fish_seen_subcommand_from create-window; and not __fish_seen_subcommand_from help" -s h -l help -d 'Print help information'
-complete -c alacritty -n "__fish_seen_subcommand_from msg; and not __fish_seen_subcommand_from create-window; and not __fish_seen_subcommand_from help" -f -a "create-window" -d 'Create a new window in the same Alacritty process'
-complete -c alacritty -n "__fish_seen_subcommand_from msg; and not __fish_seen_subcommand_from create-window; and not __fish_seen_subcommand_from help" -f -a "help" -d 'Print this message or the help of the given subcommand(s)'
+complete -c alacritty -n "__fish_seen_subcommand_from msg; and not __fish_seen_subcommand_from create-window; and not __fish_seen_subcommand_from config; and not __fish_seen_subcommand_from help" -s s -l socket -d 'IPC socket connection path override' -r -F
+complete -c alacritty -n "__fish_seen_subcommand_from msg; and not __fish_seen_subcommand_from create-window; and not __fish_seen_subcommand_from config; and not __fish_seen_subcommand_from help" -s h -l help -d 'Print help information'
+complete -c alacritty -n "__fish_seen_subcommand_from msg; and not __fish_seen_subcommand_from create-window; and not __fish_seen_subcommand_from config; and not __fish_seen_subcommand_from help" -f -a "create-window" -d 'Create a new window in the same Alacritty process'
+complete -c alacritty -n "__fish_seen_subcommand_from msg; and not __fish_seen_subcommand_from create-window; and not __fish_seen_subcommand_from config; and not __fish_seen_subcommand_from help" -f -a "config" -d 'Update the Alacritty configuration'
+complete -c alacritty -n "__fish_seen_subcommand_from msg; and not __fish_seen_subcommand_from create-window; and not __fish_seen_subcommand_from config; and not __fish_seen_subcommand_from help" -f -a "help" -d 'Print this message or the help of the given subcommand(s)'
 complete -c alacritty -n "__fish_seen_subcommand_from msg; and __fish_seen_subcommand_from create-window" -l working-directory -d 'Start the shell in the specified working directory' -r -F
 complete -c alacritty -n "__fish_seen_subcommand_from msg; and __fish_seen_subcommand_from create-window" -s e -l command -d 'Command and args to execute (must be last argument)' -r
 complete -c alacritty -n "__fish_seen_subcommand_from msg; and __fish_seen_subcommand_from create-window" -s t -l title -d 'Defines the window title [default: Alacritty]' -r
 complete -c alacritty -n "__fish_seen_subcommand_from msg; and __fish_seen_subcommand_from create-window" -l class -d 'Defines window class/app_id on X11/Wayland [default: Alacritty]' -r
 complete -c alacritty -n "__fish_seen_subcommand_from msg; and __fish_seen_subcommand_from create-window" -l hold -d 'Remain open after child process exit'
 complete -c alacritty -n "__fish_seen_subcommand_from msg; and __fish_seen_subcommand_from create-window" -s h -l help -d 'Print help information'
+complete -c alacritty -n "__fish_seen_subcommand_from msg; and __fish_seen_subcommand_from config" -s w -l window-id -d 'Window ID for the new config' -r
+complete -c alacritty -n "__fish_seen_subcommand_from msg; and __fish_seen_subcommand_from config" -s r -l reset -d 'Clear all runtime configuration changes'
+complete -c alacritty -n "__fish_seen_subcommand_from msg; and __fish_seen_subcommand_from config" -s h -l help -d 'Print help information'