1 files changed, 105 insertions, 0 deletions
diff --git a/src/path.rs b/src/path.rs
new file mode 100644
index 0000000..5fb5875
--- /dev/null
+++ b/src/path.rs
@@ -0,0 +1,105 @@
+use std::env;
+use std::error::Error;
+use std::path::Path;
+
+/// Manager for a list of "search paths" on the filesystem, for the purpose of
+/// resolving the absolute path of data files that have several possible
+/// locations. See the documentation of 'find' for more information on the
+/// default search paths.
+#[derive(Debug)]
+pub struct PathManager {
+    search: Vec<String>,
+}
+
+impl PathManager {
+    // TODO: Implement the following additional search paths:
+    // - The steam paths on GNU/Linux.
+    // - The "standard" paths for OSX (See G_AddSearchPaths)
+    // - The "standard" paths for Windows (See G_AddSearchPaths)
+    // - Those specified on the command-line.
+    //   - See the CommandPaths and CommandGrps globals in common.cpp
+    // - The "app dir" on OSX.
+    // - PROPERLY add the CWD.
+    // - $HOME/apps/rebuild/ (?)
+    // - $HOME/.config/rebuild/
+    // - Those specified via DUKE3DGRP environment variable.
+    //   - See JBF 20031220
+
+    /// Create a new PathManager and initialize the search path list with
+    /// acceptable defaults. See the documentation of 'find' for more
+    /// information on the default search paths.
+    pub fn new() -> PathManager {
+        let mut result = PathManager { search: Vec::new() };
+
+        let directories = vec![
+            ".",
+            "/usr/share/games/jfduke3d",
+            "/usr/local/share/games/jfduke3d",
+            "/usr/share/games/eduke32",
+            "/usr/local/share/games/eduke32",
+            "/usr/share/games/rebuild",
+            "/usr/local/share/games/rebuild",
+        ];
+
+        for directory in directories.iter() {
+            result.add_path(directory).ok();
+        }
+
+        let directories = vec![
+            "$HOME/.rebuild",
+        ];
+
+        if let Some(home) = env::home_dir() {
+            if let Some(home) = home.to_str() {
+                for path in directories.iter() {
+                    let path = String::from(*path).replace("$HOME", home);
+                    result.add_path(&path).ok();
+                }
+            }
+        }
+
+        result
+    }
+
+    /// Add an additional path for searching.
+    ///
+    /// # Errors
+    ///
+    /// A return value of 'Err' indicates that the given path did not exist.
+    pub fn add_path(&mut self, path: &str) -> Result<(), Box<Error>> {
+        if Path::new(&path).exists() {
+            self.search.push(String::from(path));
+        } else {
+            bail!("Path does not exist");
+        }
+
+        Ok(())
+    }
+
+    /// Go through the search path list in order and return the first existing
+    /// path with the the given name, or None if no such file was found. The
+    /// default search path order is:
+    ///
+    /// - ".",
+    /// - "/usr/local/share/games/rebuild",
+    /// - "/usr/share/games/rebuild",
+    /// - "/usr/local/share/games/eduke32",
+    /// - "/usr/share/games/eduke32",
+    /// - "/usr/local/share/games/jfduke3d",
+    /// - "/usr/share/games/jfduke3d",
+    /// - "$HOME/.rebuild",
+    ///
+    /// This is followed by any additional paths in the search path list tha`t
+    /// were added by 'add_path'.
+    pub fn find(&self, name: &str) -> Option<String> {
+        for directory in self.search.iter() {
+            let path = format!("{}/{}", directory, name);
+
+            if Path::new(&path).exists() {
+                return Some(path);
+            }
+        }
+
+        None
+    }
+}