Add read_dir to mod_util::Mod (#232)

mod_util/src/mod_loader.rs

@@ -5,6 +5,7 @@
     path::{Path, PathBuf},
 };
 
+use zip::read::ZipFile;
 use zip::ZipArchive;
 
 use crate::mod_info::{ModInfo, Version};
@@ -158,12 +159,61 @@
         self.internal.get_file(path)
     }
 
+    // Returns a list of all files/subdirectories that live in `dir`.
+    pub fn read_dir(&self, dir: &str) -> Result<Vec<ModEntry>> {
+        self.internal.read_dir(dir)
+    }
+
     #[must_use]
     pub const fn wube_mods() -> [&'static str; 5] {
         ["core", "base", "elevated-rails", "quality", "space-age"]
     }
 }
 
+/// An object which represents a file or folder inside of a Mod, like `fs::DirEntry`.
+#[derive(Debug)]
+pub struct ModEntry {
+    path: PathBuf,
+    is_file: bool,
+    // Can add all sorts of fancy info as we like
+}
+
+impl ModEntry {
+    pub fn path(&self) -> &PathBuf {
+        &self.path
+    }
+    pub fn is_file(&self) -> bool {
+        self.is_file
+    }
+    pub fn is_dir(&self) -> bool {
+        !self.is_file
+    }
+    // I don't think we have to worry about symlinks...
+}
+
+impl TryFrom<std::fs::DirEntry> for ModEntry {
+    type Error = ModError;
+
+    fn try_from(item: std::fs::DirEntry) -> Result<ModEntry> {
+        let metadata = item.metadata()?;
+        Ok(ModEntry {
+            path: item.path(),
+            is_file: metadata.is_file(),
+        })
+    }
+}
+
+impl TryFrom<&ZipFile<'_, File>> for ModEntry {
+    type Error = ModError;
+
+    fn try_from(item: &ZipFile<'_, File>) -> Result<ModEntry> {
+        Ok(ModEntry {
+            path: item.name().into(),
+            is_file: item.is_file(),
+        })
+    }
+}
+
 #[derive(Debug)]
 enum ModType {
     Folder {
@@ -258,6 +308,47 @@
             }
         }
     }
+
+    fn read_dir(&self, dir: &str) -> Result<Vec<ModEntry>> {
+        match self {
+            Self::Folder { path } => {
+                let path = path.join(dir);
+                if !path.exists() {
+                    return Err(ModError::PathDoesNotExist(path));
+                }
+
+                return std::fs::read_dir(&path)?
+                    .filter_map(|x| x.ok())
+                    .map(|x| ModEntry::try_from(x))
+                    .collect();
+            }
+            Self::Zip {
+                internal_prefix,
+                zip,
+                ..
+            } => {
+                let path = internal_prefix.clone() + dir;
+                let mut zip = zip.try_borrow_mut()?;
+
+                if let Err(_) = &zip.by_name(&path) {
+                    return Err(ModError::PathDoesNotExist(path.into()));
+                }
+
+                // We need to copy all of the `&str`s to `String`s so we don't
+                // keep the immutable ref to `zip` alive and trigger a double borrow
+                let entries: Vec<String> = zip
+                    .file_names()
+                    .filter(|&x| x.starts_with(&path) && x != path)
+                    .map(|x| x.into())
+                    .collect();
+
+                return entries
+                    .iter()
+                    .map(|x| ModEntry::try_from(&zip.by_name(x)?))
+                    .collect();
+            }
+        }
+    }
 }
 
 fn get_zip_internal_folder(path: impl AsRef<Path>, zip: &ZipArchive<File>) -> Result<String> {