Respect XDG_CACHE_HOME on Linux and Mac (zed-extensions#168)

Address zed-extensions#167

When the environmental variable XDG_CACHE_HOME is set, it takes
precedence over the cache path rooted at HOME

Author: tartarughina

src/java.rs

@@ -288,7 +288,7 @@ impl Extension for Java {
                 self.lombok_jar_path(language_server_id, &configuration, worktree)?;
             let canonical_lombok_jar_path = path_to_string(current_dir.join(lombok_jar_path))?;
 
-            Some(format!("-javaagent:{}", canonical_lombok_jar_path))
+            Some(format!("-javaagent:{canonical_lombok_jar_path}"))
         } else {
             None
         };

src/jdtls.rs

@@ -317,15 +317,28 @@ fn get_jdtls_data_path(worktree: &Worktree) -> zed::Result<PathBuf> {
     // we fall back to the the extension's workdir, which may never get cleaned up.
     // In future we may want to deliberately manage caches to be able to force-clean them.
 
-    let mut env_iter = worktree.shell_env().into_iter();
+    let env = worktree.shell_env();
     let base_cachedir = match current_platform().0 {
-        Os::Mac => env_iter
-            .find(|(k, _)| k == "HOME")
-            .map(|(_, v)| PathBuf::from(v).join("Library").join("Caches")),
-        Os::Linux => env_iter
-            .find(|(k, _)| k == "HOME")
-            .map(|(_, v)| PathBuf::from(v).join(".cache")),
-        Os::Windows => env_iter
+        Os::Mac => env
+            .iter()
+            .find(|(k, _)| k == "XDG_CACHE_HOME")
+            .map(|(_, v)| PathBuf::from(v))
+            .or_else(|| {
+                env.iter()
+                    .find(|(k, _)| k == "HOME")
+                    .map(|(_, v)| PathBuf::from(v).join("Library").join("Caches"))
+            }),
+        Os::Linux => env
+            .iter()
+            .find(|(k, _)| k == "XDG_CACHE_HOME")
+            .map(|(_, v)| PathBuf::from(v))
+            .or_else(|| {
+                env.iter()
+                    .find(|(k, _)| k == "HOME")
+                    .map(|(_, v)| PathBuf::from(v).join(".cache"))
+            }),
+        Os::Windows => env
+            .iter()
             .find(|(k, _)| k == "APPDATA")
             .map(|(_, v)| PathBuf::from(v)),
     }