Crash guard: prevent loading of preset if it has caused crashes.

src/CrashGuard.cpp

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+/*
+ *   Copyright (c) 2025 Robin E. R. Davies
+ *   All rights reserved.
+
+ *   Permission is hereby granted, free of charge, to any person obtaining a copy
+ *   of this software and associated documentation files (the "Software"), to deal
+ *   in the Software without restriction, including without limitation the rights
+ *   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ *   copies of the Software, and to permit persons to whom the Software is
+ *   furnished to do so, subject to the following conditions:
+
+ *   The above copyright notice and this permission notice shall be included in all
+ *   copies or substantial portions of the Software.
+
+ *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ *   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ *   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ *   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ *   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ *   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ *   SOFTWARE.
+ */
+
+#include "CrashGuard.hpp"
+#include "ofstream_synced.hpp"
+#include <fstream>
+#include <Lv2Log.hpp>
+
+using namespace pipedal;
+namespace fs = std::filesystem;
+
+int CrashGuard::crashCount = 0;
+std::mutex CrashGuard::mutex;
+std::filesystem::path CrashGuard::fileName;
+int64_t CrashGuard::depth = 0;
+
+void CrashGuard::SetCrashGuardFileName(const std::filesystem::path &path)
+{
+    CrashGuard::fileName = path;
+
+    {
+        std::ifstream f{path};
+        if (f.is_open())
+        {
+            f >> crashCount;
+        }
+        if (crashCount > 0) {
+            Lv2Log::info("CrashGuard: Detected previous crash, count = %d", (int)crashCount);
+        }
+    }
+}
+bool CrashGuard::HasCrashed()
+{
+    return crashCount > 4;
+}
+void CrashGuard::ClearCrashFlag()
+{
+    crashCount = 0;
+    try
+    {
+        if (fs::exists(fileName))
+        {
+            fs::remove(fileName);
+        }
+    }
+    catch (const std::exception &ignored)
+    {
+    }
+}
+
+void CrashGuard::EnterCrashGuardZone()
+{
+    std::lock_guard lock{mutex};
+
+    if (depth++ == 0)
+    {
+        if (!fileName.empty()) {
+            ofstream_synced f{fileName};
+            f << (crashCount + 1) << std::endl;
+        }
+    }
+}
+void CrashGuard::LeaveCrashGuardZone()
+{
+    std::lock_guard lock{mutex};
+    if (--depth == 0)
+    {
+        try
+        {
+            if (!fileName.empty() && fs::exists(fileName))
+            {
+                fs::remove(fileName);
+            }
+        }
+        catch (const std::exception &ignored)
+        {
+        }
+    }
+}