fix(persisted-scope): Prevent out-of-memory issues, fixes #274 (#328)

* fix(persisted-scope): Unescape paths before saving to disk.

* fix cfg flags

* dedupe code

* unescape when reading to try to fix existing files

* add more patterns. only fix pattern on app start. don't check if pattern is allowed already.

* remove dbg log

* typo

* remove unused imports

* clippy

* fix compilation with asset-protocol feature flag enabled

* update patterns

* manually re-save state once

* add changefile

* remove dbg print

.changes/persisted-scope-fix-oom.md

@@ -0,0 +1,5 @@
+---
+persisted-scope: patch
+---
+
+Recursively unescape saved patterns before allowing/forbidding them. This effectively prevents `.persisted-scope` files from blowing up, which caused Out-Of-Memory issues, while automatically fixing existing broken files seamlessly.

plugins/persisted-scope/Cargo.toml

@@ -15,6 +15,7 @@ serde_json.workspace = true
 tauri.workspace = true
 log.workspace = true
 thiserror.workspace = true
+aho-corasick = "0.7"
 bincode = "1"
 
 [features]

plugins/persisted-scope/src/lib.rs

@@ -2,19 +2,34 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-License-Identifier: MIT
 
+use aho_corasick::AhoCorasick;
 use serde::{Deserialize, Serialize};
 use tauri::{
     plugin::{Builder, TauriPlugin},
-    FsScopeEvent, Manager, Runtime,
+    AppHandle, FsScopeEvent, Manager, Runtime,
 };
 
 use std::{
     fs::{create_dir_all, File},
     io::Write,
+    path::Path,
 };
 
 const SCOPE_STATE_FILENAME: &str = ".persisted-scope";
 
+// Most of these patterns are just added to try to fix broken files in the wild.
+// After a while we can hopefully reduce it to something like [r"[?]", r"[*]", r"\\?\\\?\"]
+const PATTERNS: &[&str] = &[
+    r"[[]",
+    r"[]]",
+    r"[?]",
+    r"[*]",
+    r"\?\?",
+    r"\\?\\?\",
+    r"\\?\\\?\",
+];
+const REPLACE_WITH: &[&str] = &[r"[", r"]", r"?", r"*", r"\?", r"\\?\", r"\\?\"];
+
 #[derive(Debug, thiserror::Error)]
 enum Error {
     #[error(transparent)]
@@ -33,6 +48,41 @@ struct Scope {
     forbidden_patterns: Vec<String>,
 }
 
+fn fix_pattern(ac: &AhoCorasick, s: &str) -> String {
+    let s = ac.replace_all(s, REPLACE_WITH);
+
+    if ac.find(&s).is_some() {
+        return fix_pattern(ac, &s);
+    }
+
+    s
+}
+
+fn save_scopes<R: Runtime>(app: &AppHandle<R>, app_dir: &Path, scope_state_path: &Path) {
+    let fs_scope = app.fs_scope();
+
+    let scope = Scope {
+        allowed_paths: fs_scope
+            .allowed_patterns()
+            .into_iter()
+            .map(|p| p.to_string())
+            .collect(),
+        forbidden_patterns: fs_scope
+            .forbidden_patterns()
+            .into_iter()
+            .map(|p| p.to_string())
+            .collect(),
+    };
+
+    let _ = create_dir_all(app_dir)
+        .and_then(|_| File::create(scope_state_path))
+        .map_err(Error::Io)
+        .and_then(|mut f| {
+            f.write_all(&bincode::serialize(&scope).map_err(Error::from)?)
+                .map_err(Into::into)
+        });
+}
+
 pub fn init<R: Runtime>() -> TauriPlugin<R> {
     Builder::new("persisted-scope")
         .setup(|app| {
@@ -49,49 +99,38 @@ pub fn init<R: Runtime>() -> TauriPlugin<R> {
                 #[cfg(feature = "protocol-asset")]
                 let _ = asset_protocol_scope.forbid_file(&scope_state_path);
 
+                // We're trying to fix broken .persisted-scope files seamlessly, so we'll be running this on the values read on the saved file.
+                // We will still save some semi-broken values because the scope events are quite spammy and we don't want to reduce runtime performance any further.
+                let ac = AhoCorasick::new_auto_configured(PATTERNS);
+
                 if scope_state_path.exists() {
                     let scope: Scope = tauri::api::file::read_binary(&scope_state_path)
                         .map_err(Error::from)
                         .and_then(|scope| bincode::deserialize(&scope).map_err(Into::into))
                         .unwrap_or_default();
                     for allowed in &scope.allowed_paths {
-                        // allows the path as is
-                        let _ = fs_scope.allow_file(allowed);
+                        let allowed = fix_pattern(&ac, allowed);
+
+                        let _ = fs_scope.allow_file(&allowed);
                         #[cfg(feature = "protocol-asset")]
-                        let _ = asset_protocol_scope.allow_file(allowed);
+                        let _ = asset_protocol_scope.allow_file(&allowed);
                     }
                     for forbidden in &scope.forbidden_patterns {
-                        // forbid the path as is
-                        let _ = fs_scope.forbid_file(forbidden);
+                        let forbidden = fix_pattern(&ac, forbidden);
+
+                        let _ = fs_scope.forbid_file(&forbidden);
                         #[cfg(feature = "protocol-asset")]
-                        let _ = asset_protocol_scope.forbid_file(forbidden);
+                        let _ = asset_protocol_scope.forbid_file(&forbidden);
                     }
+
+                    // Manually save the fixed scopes to disk once.
+                    // This is needed to fix broken .peristed-scope files in case the app doesn't update the scope itself.
+                    save_scopes(&app, &app_dir, &scope_state_path);
                 }
 
                 fs_scope.listen(move |event| {
-                    let fs_scope = app.fs_scope();
                     if let FsScopeEvent::PathAllowed(_) = event {
-                        let scope = Scope {
-                            allowed_paths: fs_scope
-                                .allowed_patterns()
-                                .into_iter()
-                                .map(|p| p.to_string())
-                                .collect(),
-                            forbidden_patterns: fs_scope
-                                .forbidden_patterns()
-                                .into_iter()
-                                .map(|p| p.to_string())
-                                .collect(),
-                        };
-                        let scope_state_path = scope_state_path.clone();
-
-                        let _ = create_dir_all(&app_dir)
-                            .and_then(|_| File::create(scope_state_path))
-                            .map_err(Error::Io)
-                            .and_then(|mut f| {
-                                f.write_all(&bincode::serialize(&scope).map_err(Error::from)?)
-                                    .map_err(Into::into)
-                            });
+                        save_scopes(&app, &app_dir, &scope_state_path);
                     }
                 });
             }