Feat: store data next to exe when writable (portable mode)

src/app/session.rs

@@ -1,3 +1,4 @@
+use std::fs;
 use std::path::{Path, PathBuf};
 use std::time::{Duration, SystemTime, UNIX_EPOCH};
 
@@ -19,6 +20,7 @@ pub const DEFAULT_WORD_WRAP_ENABLED: bool = true;
 pub const DEFAULT_ALWAYS_ON_TOP: bool = false;
 
 const APP_DIR_NAME: &str = "Rivet";
+const PORTABLE_DATA_DIR_NAME: &str = "data";
 const SESSIONS_DIR_NAME: &str = "sessions";
 const BACKUP_DIR_NAME: &str = "backup";
 const SESSION_FILE_NAME: &str = "session.json";
@@ -198,7 +200,33 @@ pub fn decide_restore_source(input: &RestoreDecisionInput) -> RestoreSource {
     }
 }
 
+/// Data directory next to the executable, used when that location is
+/// writable (i.e. running as a portable build, not installed under a
+/// protected directory like Program Files). Returns `None` if the exe path
+/// can't be resolved or the directory isn't writable, in which case the
+/// caller falls back to the per-user AppData location.
+fn portable_data_dir() -> Option<PathBuf> {
+    if cfg!(test) {
+        // Tests exercise data_dir() via LOCALAPPDATA/APPDATA env overrides;
+        // the test binary's own directory is writable, which would
+        // short-circuit those overrides and scribble into target/.
+        return None;
+    }
+    let exe = std::env::current_exe().ok()?;
+    let exe_dir = exe.parent()?;
+    let candidate = exe_dir.join(PORTABLE_DATA_DIR_NAME);
+    fs::create_dir_all(&candidate).ok()?;
+    let probe = candidate.join(".write_test");
+    fs::write(&probe, b"").ok()?;
+    let _ = fs::remove_file(&probe);
+    Some(candidate)
+}
+
 pub fn data_dir() -> Result<PathBuf> {
+    if let Some(portable) = portable_data_dir() {
+        return Ok(portable);
+    }
+
     if let Ok(local) = std::env::var("LOCALAPPDATA")
         && !local.is_empty()
     {

src/logging.rs

@@ -4,10 +4,7 @@ use std::path::{Path, PathBuf};
 use std::sync::{Mutex, OnceLock};
 use std::time::{SystemTime, UNIX_EPOCH};
 
-use windows::Win32::Foundation::HANDLE;
-use windows::Win32::System::Com::CoTaskMemFree;
-use windows::Win32::UI::Shell::{FOLDERID_LocalAppData, KNOWN_FOLDER_FLAG, SHGetKnownFolderPath};
-
+use crate::app::session;
 use crate::error::{AppError, Result};
 
 const MAX_LOG_SIZE: u64 = 512 * 1024;
@@ -81,26 +78,8 @@ fn open_log_file() -> Result<File> {
 }
 
 fn log_directory() -> Result<PathBuf> {
-    let path = local_appdata_path().unwrap_or_else(std::env::temp_dir);
-    Ok(path.join("Rivet").join("logs"))
-}
-
-fn local_appdata_path() -> Option<PathBuf> {
-    let path =
-        unsafe { SHGetKnownFolderPath(&FOLDERID_LocalAppData, KNOWN_FOLDER_FLAG(0), HANDLE(0)) }
-            .ok()?;
-    let buffer = unsafe {
-        let mut length = 0usize;
-        while *path.0.add(length) != 0 {
-            length += 1;
-        }
-        std::slice::from_raw_parts(path.0, length)
-    };
-    let value = String::from_utf16(buffer).ok().map(PathBuf::from);
-    unsafe {
-        CoTaskMemFree(Some(path.0 as _));
-    }
-    value
+    let path = session::data_dir().unwrap_or_else(|_| std::env::temp_dir().join("Rivet"));
+    Ok(path.join("logs"))
 }
 
 fn rotate_logs(path: &Path) -> Result<()> {