add a CLI flag for specifying config file location (#2666)

8 files changed, 48 insertions, 16 deletions

diff --git a/book/src/configuration.md b/book/src/configuration.md
index 5eb94c4e..e418869f 100644
--- a/book/src/configuration.md
+++ b/book/src/configuration.md
@@ -25,6 +25,9 @@ select = "underline"
 hidden = false
 ```
 
+You may also specify a file to use for configuration with the `-c` or
+`--config` CLI argument: `hx -c path/to/custom-config.toml`.
+
 ## Editor
 
 ### `[editor]` Section
diff --git a/contrib/completion/hx.bash b/contrib/completion/hx.bash
index 87c34028..8a2d9777 100644
--- a/contrib/completion/hx.bash
+++ b/contrib/completion/hx.bash
@@ -16,7 +16,7 @@ _hx() {
 		COMPREPLY=($(compgen -W "$languages" -- $2))
 		;;
 	*)
-		COMPREPLY=($(compgen -fd -W "-h --help --tutor -V --version -v -vv -vvv --health -g --grammar --vsplit --hsplit" -- $2))
+		COMPREPLY=($(compgen -fd -W "-h --help --tutor -V --version -v -vv -vvv --health -g --grammar --vsplit --hsplit -c --config" -- $2))
 		;;
 	esac
 } && complete -F _hx hx
diff --git a/contrib/completion/hx.fish b/contrib/completion/hx.fish
index df2fb500..65f248d4 100644
--- a/contrib/completion/hx.fish
+++ b/contrib/completion/hx.fish
@@ -11,3 +11,4 @@ complete -c hx -s v -o vv -o vvv -d "Increases logging verbosity"
 complete -c hx -s V -l version -d "Prints version information"
 complete -c hx -l vsplit -d "Splits all given files vertically into different windows"
 complete -c hx -l hsplit -d "Splits all given files horizontally into different windows"
+complete -c hx -s c -l config -d "Specifies a file to use for completion"
diff --git a/contrib/completion/hx.zsh b/contrib/completion/hx.zsh
index f9d58d3c..e3375656 100644
--- a/contrib/completion/hx.zsh
+++ b/contrib/completion/hx.zsh
@@ -16,6 +16,8 @@ _hx() {
 		"--grammar[Fetches or builds tree-sitter grammars]:action:->grammar" \
 		"--vsplit[Splits all given files vertically into different windows]" \
 		"--hsplit[Splits all given files horizontally into different windows]" \
+		"-c[Specifies a file to use for configuration]" \
+		"--config[Specifies a file to use for configuration]" \
 		"*:file:_files"
 
 	case "$state" in
diff --git a/helix-loader/src/lib.rs b/helix-loader/src/lib.rs
index 1ba48e7b..015b39a5 100644
--- a/helix-loader/src/lib.rs
+++ b/helix-loader/src/lib.rs
@@ -2,11 +2,28 @@ pub mod config;
 pub mod grammar;
 
 use etcetera::base_strategy::{choose_base_strategy, BaseStrategy};
+use std::path::PathBuf;
 
-pub static RUNTIME_DIR: once_cell::sync::Lazy<std::path::PathBuf> =
-    once_cell::sync::Lazy::new(runtime_dir);
+pub static RUNTIME_DIR: once_cell::sync::Lazy<PathBuf> = once_cell::sync::Lazy::new(runtime_dir);
 
-pub fn runtime_dir() -> std::path::PathBuf {
+static CONFIG_FILE: once_cell::sync::OnceCell<PathBuf> = once_cell::sync::OnceCell::new();
+
+pub fn initialize_config_file(specified_file: Option<PathBuf>) {
+    let config_file = specified_file.unwrap_or_else(|| {
+        let config_dir = config_dir();
+
+        if !config_dir.exists() {
+            std::fs::create_dir_all(&config_dir).ok();
+        }
+
+        config_dir.join("config.toml")
+    });
+
+    // We should only initialize this value once.
+    CONFIG_FILE.set(config_file).ok();
+}
+
+pub fn runtime_dir() -> PathBuf {
     if let Ok(dir) = std::env::var("HELIX_RUNTIME") {
         return dir.into();
     }
@@ -31,7 +48,7 @@ pub fn runtime_dir() -> std::path::PathBuf {
         .unwrap()
 }
 
-pub fn config_dir() -> std::path::PathBuf {
+pub fn config_dir() -> PathBuf {
     // TODO: allow env var override
     let strategy = choose_base_strategy().expect("Unable to find the config directory!");
     let mut path = strategy.config_dir();
@@ -39,7 +56,7 @@ pub fn config_dir() -> std::path::PathBuf {
     path
 }
 
-pub fn local_config_dirs() -> Vec<std::path::PathBuf> {
+pub fn local_config_dirs() -> Vec<PathBuf> {
     let directories = find_root_impl(None, &[".helix".to_string()])
         .into_iter()
         .map(|path| path.join(".helix"))
@@ -48,7 +65,7 @@ pub fn local_config_dirs() -> Vec<std::path::PathBuf> {
     directories
 }
 
-pub fn cache_dir() -> std::path::PathBuf {
+pub fn cache_dir() -> PathBuf {
     // TODO: allow env var override
     let strategy = choose_base_strategy().expect("Unable to find the config directory!");
     let mut path = strategy.cache_dir();
@@ -56,19 +73,22 @@ pub fn cache_dir() -> std::path::PathBuf {
     path
 }
 
-pub fn config_file() -> std::path::PathBuf {
-    config_dir().join("config.toml")
+pub fn config_file() -> PathBuf {
+    CONFIG_FILE
+        .get()
+        .map(|path| path.to_path_buf())
+        .unwrap_or_else(|| config_dir().join("config.toml"))
 }
 
-pub fn lang_config_file() -> std::path::PathBuf {
+pub fn lang_config_file() -> PathBuf {
     config_dir().join("languages.toml")
 }
 
-pub fn log_file() -> std::path::PathBuf {
+pub fn log_file() -> PathBuf {
     cache_dir().join("helix.log")
 }
 
-pub fn find_root_impl(root: Option<&str>, root_markers: &[String]) -> Vec<std::path::PathBuf> {
+pub fn find_root_impl(root: Option<&str>, root_markers: &[String]) -> Vec<PathBuf> {
     let current_dir = std::env::current_dir().expect("unable to determine current directory");
     let mut directories = Vec::new();
 
diff --git a/helix-term/src/application.rs b/helix-term/src/application.rs
index 50e72cf7..527ca1c7 100644
--- a/helix-term/src/application.rs
+++ b/helix-term/src/application.rs
@@ -89,9 +89,8 @@ impl Application {
 
         use helix_view::editor::Action;
 
-        let config_dir = helix_loader::config_dir();
         let theme_loader = std::sync::Arc::new(theme::Loader::new(
-            &config_dir,
+            &helix_loader::config_dir(),
             &helix_loader::runtime_dir(),
         ));
 
diff --git a/helix-term/src/args.rs b/helix-term/src/args.rs
index c3019ea7..d16d7dfd 100644
--- a/helix-term/src/args.rs
+++ b/helix-term/src/args.rs
@@ -14,6 +14,7 @@ pub struct Args {
     pub build_grammars: bool,
     pub split: Option<Layout>,
     pub verbosity: u64,
+    pub config_file: Option<PathBuf>,
     pub files: Vec<(PathBuf, Position)>,
 }
 
@@ -43,6 +44,10 @@ impl Args {
                         anyhow::bail!("--grammar must be followed by either 'fetch' or 'build'")
                     }
                 },
+                "-c" | "--config" => match argv.next().as_deref() {
+                    Some(path) => args.config_file = Some(path.into()),
+                    None => anyhow::bail!("--config must specify a path to read"),
+                },
                 arg if arg.starts_with("--") => {
                     anyhow::bail!("unexpected double dash argument: {}", arg)
                 }
diff --git a/helix-term/src/main.rs b/helix-term/src/main.rs
index 83af7588..7f04f201 100644
--- a/helix-term/src/main.rs
+++ b/helix-term/src/main.rs
@@ -64,6 +64,7 @@ FLAGS:
     --health [LANG]                Checks for potential errors in editor setup
                                    If given, checks for config errors in language LANG
     -g, --grammar {{fetch|build}}    Fetches or builds tree-sitter grammars listed in languages.toml
+    -c, --config <file>            Specifies a file to use for configuration
     -v                             Increases logging verbosity each use for up to 3 times
                                    (default file: {})
     -V, --version                  Prints version information
@@ -119,14 +120,15 @@ FLAGS:
         std::fs::create_dir_all(&config_dir).ok();
     }
 
-    let config = match std::fs::read_to_string(config_dir.join("config.toml")) {
+    helix_loader::initialize_config_file(args.config_file.clone());
+
+    let config = match std::fs::read_to_string(helix_loader::config_file()) {
         Ok(config) => toml::from_str(&config)
             .map(helix_term::keymap::merge_keys)
             .unwrap_or_else(|err| {
                 eprintln!("Bad config: {}", err);
                 eprintln!("Press <ENTER> to continue with default config");
                 use std::io::Read;
-                // This waits for an enter press.
                 let _ = std::io::stdin().read(&mut []);
                 Config::default()
             }),