add config for the mux socket path

src/config.rs

@@ -3,7 +3,7 @@
 use crate::font::FontSystemSelection;
 use crate::frontend::FrontEndSelection;
 use crate::{get_shell, Command};
-use directories::UserDirs;
+use directories::{ProjectDirs, UserDirs};
 use failure::{err_msg, Error};
 use std;
 use std::ffi::OsStr;
@@ -65,6 +65,10 @@ pub struct Config {
 
     #[serde(default)]
     pub front_end: FrontEndSelection,
+
+    /// When using the MuxServer, this specifies the path to the unix
+    /// domain socket to use to communicate with the mux server.
+    pub mux_server_unix_domain_socket_path: Option<String>,
 }
 
 fn default_hyperlink_rules() -> Vec<hyperlink::Rule> {
@@ -102,6 +106,7 @@ impl Default for Config {
             hyperlink_rules: default_hyperlink_rules(),
             term: default_term(),
             default_prog: None,
+            mux_server_unix_domain_socket_path: None,
         }
     }
 }
@@ -283,15 +288,23 @@ pub struct StyleRule {
     pub font: TextStyle,
 }
 
+fn project_dirs() -> Result<ProjectDirs, Error> {
+    ProjectDirs::from("org", "wez", "wezterm").ok_or_else(|| err_msg("can't find project dirs"))
+}
+
 impl Config {
     pub fn load() -> Result<Self, Error> {
+        let project_dirs = project_dirs()?;
         let dirs = UserDirs::new().ok_or_else(|| err_msg("can't find home dir"))?;
         let home = dirs.home_dir();
 
         // Note that the directories crate has methods for locating project
         // specific config directories, but only returns one of them, not
-        // multiple.  Not sure how feel about that.
+        // multiple, so we use it for one of the paths, and fill in the fallbacks
+        // manually here.  This will likely result in trying the same path
+        // a couple of times, but that's harmless.
         let paths = [
+            project_dirs.config_dir().join("wezterm.toml"),
             home.join(".config").join("wezterm").join("wezterm.toml"),
             home.join(".wezterm.toml"),
         ];
@@ -310,21 +323,31 @@ impl Config {
 
             let cfg: Self = toml::from_str(&s)
                 .map_err(|e| format_err!("Error parsing TOML from {}: {:?}", p.display(), e))?;
-            return Ok(cfg.compute_extra_defaults());
+            return Ok(cfg.compute_extra_defaults(project_dirs));
         }
 
-        Ok(Self::default_config())
+        Ok(Self::default().compute_extra_defaults(project_dirs))
     }
 
     pub fn default_config() -> Self {
-        Self::default().compute_extra_defaults()
+        let project_dirs = project_dirs().unwrap();
+        Self::default().compute_extra_defaults(project_dirs)
     }
 
     /// In some cases we need to compute expanded values based
     /// on those provided by the user.  This is where we do that.
-    fn compute_extra_defaults(&self) -> Self {
+    fn compute_extra_defaults(&self, project_dirs: ProjectDirs) -> Self {
         let mut cfg = self.clone();
 
+        if cfg.mux_server_unix_domain_socket_path.is_none() {
+            cfg.mux_server_unix_domain_socket_path = match project_dirs.runtime_dir() {
+                Some(path) => path.join("sock"),
+                None => project_dirs.data_local_dir().join("sock"),
+            }
+            .to_str()
+            .map(str::to_owned);
+        }
+
         if cfg.font_rules.is_empty() {
             // Expand out some reasonable default font rules
             let bold = self.font.make_bold();