Touch up etcetera cache dir code

Cargo.toml

@@ -37,7 +37,7 @@ termcolor = "1.0"
 toml = "0.8"
 toolchain_find = "0.4"
 
-[target.'cfg(windows)'.dependencies]
+[target.'cfg(all(windows, not(target_vendor = "uwp")))'.dependencies]
 windows-sys = { version = "0.59", features = ["Win32_Foundation", "Win32_System_Com", "Win32_UI_Shell"] }
 
 [package.metadata.docs.rs]

src/assets.rs

@@ -32,96 +32,70 @@ pub fn cache_dir() -> Result<PathBuf> {
 
 #[cfg(windows)]
 mod windows {
+    use std::env;
     use std::path::{Path, PathBuf};
 
-    fn dir_inner(env: &'static str) -> Option<PathBuf> {
+    pub fn cache_dir(home_dir: &Path) -> PathBuf {
-        std::env::var_os(env)
+        env::var_os("LOCALAPPDATA")
             .filter(|s| !s.is_empty())
             .map(PathBuf::from)
-            .or_else(|| dir_crt(env))
+            .or_else(dir_crt)
+            .unwrap_or_else(|| home_dir.join("AppData").join("Local"))
     }
 
     // Ref: https://github.com/rust-lang/cargo/blob/home-0.5.11/crates/home/src/windows.rs
     // We should keep this code in sync with the above.
     #[cfg(not(target_vendor = "uwp"))]
-    fn dir_crt(env: &'static str) -> Option<PathBuf> {
+    fn dir_crt() -> Option<PathBuf> {
         use std::ffi::OsString;
         use std::os::windows::ffi::OsStringExt;
         use std::ptr;
         use std::slice;
-
         use windows_sys::Win32::Foundation::S_OK;
         use windows_sys::Win32::System::Com::CoTaskMemFree;
         use windows_sys::Win32::UI::Shell::{
-            FOLDERID_LocalAppData, FOLDERID_RoamingAppData, SHGetKnownFolderPath,
+            FOLDERID_LocalAppData, SHGetKnownFolderPath, KF_FLAG_DONT_VERIFY,
-            KF_FLAG_DONT_VERIFY,
         };
 
         extern "C" {
             fn wcslen(buf: *const u16) -> usize;
         }
 
-        let folder_id = match env {
+        let mut path = ptr::null_mut();
-            "APPDATA" => FOLDERID_RoamingAppData,
+        let S_OK = (unsafe {
-            "LOCALAPPDATA" => FOLDERID_LocalAppData,
+            SHGetKnownFolderPath(
-            _ => return None,
+                &FOLDERID_LocalAppData,
+                KF_FLAG_DONT_VERIFY as u32,
+                ptr::null_mut(),
+                &mut path,
+            )
+        }) else {
+            // Free any allocated memory even on failure. A null ptr is a no-op for `CoTaskMemFree`.
+            unsafe { CoTaskMemFree(path.cast()) };
+            return None;
         };
 
-        unsafe {
+        let path_slice = unsafe { slice::from_raw_parts(path, wcslen(path)) };
-            let mut path = ptr::null_mut();
+        let s = OsString::from_wide(path_slice);
-            match SHGetKnownFolderPath(
+        unsafe { CoTaskMemFree(path.cast()) };
-                &folder_id,
+        Some(PathBuf::from(s))
-                KF_FLAG_DONT_VERIFY as u32,
-                std::ptr::null_mut(),
-                &mut path,
-            ) {
-                S_OK => {
-                    let path_slice = slice::from_raw_parts(path, wcslen(path));
-                    let s = OsString::from_wide(path_slice);
-                    CoTaskMemFree(path.cast());
-                    Some(PathBuf::from(s))
-                }
-                _ => {
-                    // Free any allocated memory even on failure. A null ptr is a no-op for `CoTaskMemFree`.
-                    CoTaskMemFree(path.cast());
-                    None
-                }
-            }
-        }
     }
 
     #[cfg(target_vendor = "uwp")]
-    fn dir_crt(_env: &'static str) -> Option<PathBuf> {
+    fn dir_crt() -> Option<PathBuf> {
         None
     }
-
-    pub fn cache_dir(home_dir: &Path) -> PathBuf {
-        dir_inner("LOCALAPPDATA").unwrap_or_else(|| home_dir.join("AppData").join("Local"))
-    }
 }
 
 #[cfg(not(windows))]
 mod xdg {
+    use std::env;
     use std::path::{Path, PathBuf};
 
-    fn env_var_or_none(env_var: &str) -> Option<PathBuf> {
-        std::env::var(env_var).ok().and_then(|path| {
-            let path = PathBuf::from(path);
-
-            // Return None if the path obtained from the environment variable isn’t absolute.
-            if path.is_absolute() {
-                Some(path)
-            } else {
-                None
-            }
-        })
-    }
-
-    fn env_var_or_default(home_dir: &Path, env_var: &str, default: impl AsRef<Path>) -> PathBuf {
-        env_var_or_none(env_var).unwrap_or_else(|| home_dir.join(default))
-    }
-
     pub fn cache_dir(home_dir: &Path) -> PathBuf {
-        env_var_or_default(home_dir, "XDG_CACHE_HOME", ".cache/")
+        env::var_os("XDG_CACHE_HOME")
+            .map(PathBuf::from)
+            .filter(|path| path.is_absolute())
+            .unwrap_or_else(|| home_dir.join(".cache/"))
     }
 }