V1 of laucher

src-tauri/src/settings.rs

@@ -41,11 +41,58 @@ fn settings_path(app: &AppHandle) -> Result<PathBuf, String> {
   Ok(dir.join("settings.json"))
 }
 
+/// Is this drive a disk built into the PC, rather than a USB key or a card?
+///
+/// A key plugged into a laptop takes D:, and ODIAN would install itself onto it: the
+/// database restore then stalls on the key's write speed until it gives up, and the
+/// install would vanish the moment someone unplugs it.
+#[cfg(windows)]
+fn is_fixed_drive(root: &str) -> bool {
+  use std::os::windows::ffi::OsStrExt;
+
+  use windows_sys::Win32::Storage::FileSystem::GetDriveTypeW;
+
+  /// GetDriveType's answer for a disk built into the PC (windows-sys does not export it).
+  const DRIVE_FIXED: u32 = 3;
+
+  let wide: Vec<u16> = std::ffi::OsStr::new(root).encode_wide().chain(std::iter::once(0)).collect();
+  unsafe { GetDriveTypeW(wide.as_ptr()) == DRIVE_FIXED }
+}
+
+#[cfg(not(windows))]
+fn is_fixed_drive(_root: &str) -> bool {
+  false
+}
+
+/// Does this path sit on a USB key or a card? Choosing one by hand is allowed, but it is
+/// worth saying out loud before an install spends half an hour failing on it.
+#[cfg(windows)]
+pub fn is_removable_path(path: &Path) -> bool {
+  use std::os::windows::ffi::OsStrExt;
+
+  use windows_sys::Win32::Storage::FileSystem::GetDriveTypeW;
+
+  /// GetDriveType's answer for a USB key or a card reader.
+  const DRIVE_REMOVABLE: u32 = 2;
+
+  let Some(std::path::Component::Prefix(prefix)) = path.components().next() else {
+    return false;
+  };
+  let root = format!("{}\\", prefix.as_os_str().to_string_lossy());
+  let wide: Vec<u16> = std::ffi::OsStr::new(&root).encode_wide().chain(std::iter::once(0)).collect();
+  unsafe { GetDriveTypeW(wide.as_ptr()) == DRIVE_REMOVABLE }
+}
+
+#[cfg(not(windows))]
+pub fn is_removable_path(_path: &Path) -> bool {
+  false
+}
+
 fn default_install_dir() -> String {
   // Operator PCs keep the ~1 TB of data off the system drive when a D: exists.
   // Not %LOCALAPPDATA%\ODIAN: on the release PC that folder holds the release
   // signing key, and deleting a test install must never be able to take it along.
-  if Path::new("D:\\").is_dir() {
+  if Path::new("D:\\").is_dir() && is_fixed_drive("D:\\") {
     "D:\\ODIAN".to_string()
   } else {
     "C:\\ODIAN".to_string()
@@ -56,8 +103,13 @@ fn read_site_file() -> SiteFile {
   let Some(dir) = std::env::current_exe().ok().and_then(|exe| exe.parent().map(Path::to_path_buf)) else {
     return SiteFile::default();
   };
-  std::fs::read(dir.join("site.json"))
-    .ok()
+  // Beside the exe is how a launcher copied onto a USB key is handed out, and where
+  // the NSIS installer puts the site it was built for. Tauri has moved bundled
+  // resources under `resources/` between versions, so look there too rather than
+  // silently starting with no site and asking the operator for an address.
+  ["site.json", "resources/site.json"]
+    .iter()
+    .find_map(|name| std::fs::read(dir.join(name)).ok())
     .and_then(|bytes| serde_json::from_slice(&bytes).ok())
     .unwrap_or_default()
 }