Support for rustup category home mode

Cargo.toml

@@ -118,6 +118,7 @@ features = [
   "Win32_Foundation",
   "Win32_Security",
   "Win32_Storage_FileSystem",
+  "Win32_System_Com",
   "Win32_System_Console",
   "Win32_System_Diagnostics_ToolHelp",
   "Win32_System_IO",
@@ -130,6 +131,7 @@ features = [
   "Win32_System_Threading",
   "Win32_System_WindowsProgramming",
   "Win32_UI",
+  "Win32_UI_Shell",
   "Win32_UI_WindowsAndMessaging",
 ]
 version = "0.61"

src/cli/proxy_mode.rs

@@ -14,7 +14,7 @@ pub async fn main(
     current_dir: PathBuf,
     process: &Process,
 ) -> anyhow::Result<ExitStatus> {
-    self_update::cleanup_self_updater(process, &process.cargo_home()?.join("bin"))?;
+    self_update::cleanup_self_updater(process, &process.bin_home()?)?;
 
     let _setup = job::setup();
     let mut args = process.args_os().skip(1);

src/cli/rustup_mode.rs

@@ -385,7 +385,7 @@ enum ShowSubcmd {
         verbose: bool,
     },
 
-    /// Display the computed value of RUSTUP_HOME
+    /// Display resolved Rustup home directories
     Home,
 
     /// Show the default profile used for the `rustup install` command
@@ -700,7 +700,7 @@ pub async fn main(
         .bin("rustup")
         .complete();
 
-    self_update::cleanup_self_updater(process, &process.cargo_home()?.join("bin"))?;
+    self_update::cleanup_self_updater(process, &cfg.bin_dir)?;
 
     use clap::error::ErrorKind::*;
     let matches = match Rustup::try_parse_from(process.args_os()) {
@@ -1318,14 +1318,27 @@ async fn show(cfg: &Cfg<'_>, verbose: bool) -> anyhow::Result<ExitCode> {
         cfg.default_host_tuple()?
     )?;
 
-    // Print rustup home directory
     {
         let mut t = t.lock();
-        writeln!(
-            t,
-            "{HEADER}rustup home:  {HEADER:#}{}",
-            cfg.rustup_dir.display()
-        )?;
+        if cfg.process.use_category_home() {
+            writeln!(t, "{HEADER}rustup homes:{HEADER:#}")?;
+            for (name, home) in [
+                ("config", &cfg.config_dir),
+                ("state", &cfg.state_dir),
+                ("data", &cfg.data_dir),
+                ("cache", &cfg.cache_dir),
+                ("bin", &cfg.bin_dir),
+            ] {
+                writeln!(t, "  {name}: {}", home.display())?;
+            }
+        } else {
+            // In legacy mode, all four category homes equal the resolved RUSTUP_HOME.
+            writeln!(
+                t,
+                "{HEADER}rustup home:  {HEADER:#}{}",
+                cfg.data_dir.display()
+            )?;
+        }
         writeln!(t)?;
     }
 
@@ -1473,7 +1486,21 @@ async fn show_active_toolchain(cfg: &Cfg<'_>, verbose: bool) -> anyhow::Result<E
 
 #[tracing::instrument(level = "trace", skip_all)]
 fn show_rustup_home(cfg: &Cfg<'_>) -> anyhow::Result<ExitCode> {
-    writeln!(cfg.process.stdout().lock(), "{}", cfg.rustup_dir.display())?;
+    let mut stdout = cfg.process.stdout().lock();
+    if !cfg.process.use_category_home() {
+        // In legacy mode, all four category homes equal the resolved RUSTUP_HOME.
+        writeln!(stdout, "{}", cfg.data_dir.display())?;
+        return Ok(ExitCode::SUCCESS);
+    }
+
+    for (name, home) in [
+        ("config", &cfg.config_dir),
+        ("state", &cfg.state_dir),
+        ("data", &cfg.data_dir),
+        ("cache", &cfg.cache_dir),
+    ] {
+        writeln!(stdout, "{name}: {}", home.display())?;
+    }
     Ok(ExitCode::SUCCESS)
 }
 
@@ -2191,6 +2218,10 @@ date = "2025-01-01"
                 "RUSTUP_HOME".to_owned(),
                 rustup_home.path().display().to_string(),
             ),
+            (
+                "CARGO_HOME".to_owned(),
+                rustup_home.path().display().to_string(),
+            ),
             (
                 "RUSTUP_OVERRIDE_UNIX_FALLBACK_SETTINGS".to_owned(),
                 rustup_home