Remove terminfo dependency

Fixes #4597.

Co-authored-by: Christian Duerr <contact@christianduerr.com>

2 files changed, 49 insertions, 7 deletions

diff --git a/alacritty_terminal/Cargo.toml b/alacritty_terminal/Cargo.toml
index 9bdccf7b..b859185c 100644
--- a/alacritty_terminal/Cargo.toml
+++ b/alacritty_terminal/Cargo.toml
@@ -24,8 +24,8 @@ mio-extras = "2"
 log = "0.4"
 unicode-width = "0.1"
 base64 = "0.12.0"
-terminfo = "0.7.1"
 regex-automata = "0.1.9"
+dirs = "2.0.2"
 
 [target.'cfg(unix)'.dependencies]
 nix = "0.18.0"
diff --git a/alacritty_terminal/src/tty/mod.rs b/alacritty_terminal/src/tty/mod.rs
index 7df4f140..a1c8c0c1 100644
--- a/alacritty_terminal/src/tty/mod.rs
+++ b/alacritty_terminal/src/tty/mod.rs
@@ -1,9 +1,8 @@
 //! TTY related functionality.
 
+use std::path::PathBuf;
 use std::{env, io};
 
-use terminfo::Database;
-
 use crate::config::Config;
 
 #[cfg(not(windows))]
@@ -65,10 +64,8 @@ pub fn setup_env<C>(config: &Config<C>) {
     // Default to 'alacritty' terminfo if it is available, otherwise
     // default to 'xterm-256color'. May be overridden by user's config
     // below.
-    env::set_var(
-        "TERM",
-        if Database::from_name("alacritty").is_ok() { "alacritty" } else { "xterm-256color" },
-    );
+    let terminfo = if terminfo_exists("alacritty") { "alacritty" } else { "xterm-256color" };
+    env::set_var("TERM", terminfo);
 
     // Advertise 24-bit color support.
     env::set_var("COLORTERM", "truecolor");
@@ -81,3 +78,48 @@ pub fn setup_env<C>(config: &Config<C>) {
         env::set_var(key, value);
     }
 }
+
+/// Check if a terminfo entry exists on the system.
+fn terminfo_exists(terminfo: &str) -> bool {
+    // Get first terminfo character for the parent directory.
+    let first = terminfo.get(..1).unwrap_or_default();
+    let first_hex = format!("{:x}", first.chars().next().unwrap_or_default() as usize);
+
+    // Return true if the terminfo file exists at the specified location.
+    macro_rules! check_path {
+        ($path:expr) => {
+            if $path.join(first).join(terminfo).exists()
+                || $path.join(&first_hex).join(terminfo).exists()
+            {
+                return true;
+            }
+        };
+    }
+
+    if let Some(dir) = env::var_os("TERMINFO") {
+        check_path!(PathBuf::from(&dir));
+    } else if let Some(home) = dirs::home_dir() {
+        check_path!(home.join(".terminfo"));
+    }
+
+    if let Ok(dirs) = env::var("TERMINFO_DIRS") {
+        for dir in dirs.split(':') {
+            check_path!(PathBuf::from(dir));
+        }
+    }
+
+    if let Ok(prefix) = env::var("PREFIX") {
+        let path = PathBuf::from(prefix);
+        check_path!(path.join("etc/terminfo"));
+        check_path!(path.join("lib/terminfo"));
+        check_path!(path.join("share/terminfo"));
+    }
+
+    check_path!(PathBuf::from("/etc/terminfo"));
+    check_path!(PathBuf::from("/lib/terminfo"));
+    check_path!(PathBuf::from("/usr/share/terminfo"));
+    check_path!(PathBuf::from("/boot/system/data/terminfo"));
+
+    // No valid terminfo path has been found.
+    false
+}