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.

1 files changed, 9 insertions, 0 deletions

diff --git a/alacritty/src/ipc.rs b/alacritty/src/ipc.rs
index d4c807ba..e229a048 100644
--- a/alacritty/src/ipc.rs
+++ b/alacritty/src/ipc.rs
@@ -7,6 +7,7 @@ use std::path::PathBuf;
 use std::{env, fs, process};
 
 use glutin::event_loop::EventLoopProxy;
+use glutin::window::WindowId;
 use log::warn;
 
 use alacritty_terminal::thread;
@@ -62,6 +63,14 @@ pub fn spawn_ipc_socket(options: &Options, event_proxy: EventLoopProxy<Event>) -
                     let event = Event::new(EventType::CreateWindow(options), None);
                     let _ = event_proxy.send_event(event);
                 },
+                SocketMessage::Config(ipc_config) => {
+                    let window_id = ipc_config
+                        .window_id
+                        .and_then(|id| u64::try_from(id).ok())
+                        .map(WindowId::from);
+                    let event = Event::new(EventType::IpcConfig(ipc_config), window_id);
+                    let _ = event_proxy.send_event(event);
+                },
             }
         }
     });