fix(bindings): add SafeHandleWrapper + memory growth checks; bump 0.9.1 (#571)

- Introduce SafeHandleWrapper with gating, short drain wait, and deferred release on last in-flight exit. - Wire Engine/Program/Rvm/CompiledPolicy to wrapper (centralized handle use, interop helper). - Add C# memory growth tests (using/finalizer paths) and extend xtask C# runner options. - Add pooled marshalling utilities, ResultHelpers, and API cleanups; update versions/changelog. Fixes #570. Closes #554 Signed-off-by: Anand Krishnamoorthi <anakrish@microsoft.com>
2026-08-05 02:16:11 +00:00 · 2026-02-09 23:52:05 +05:30
parent 455d2aa588
commit 96360fa9d8
39 changed files with 1496 additions and 1151 deletions
@@ -0,0 +1,272 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System;
+using System.Runtime.InteropServices;
+
+#nullable enable
+namespace Regorus
+{
+    /// <summary>
+    /// Base class for native handle wrappers that coordinates handle usage and disposal.
+    ///
+    /// Behavior summary:
+    /// - UseHandle: blocks Dispose while running; throws ObjectDisposedException if disposal has started or the handle is invalid.
+    /// - Dispose: marks disposing and blocks new calls; waits briefly for in-flight calls to finish, then defers native release to the last exiting call if needed.
+    /// - Handles are never exposed directly; derived classes can only work through UseHandle helpers.
+    ///
+    /// Concurrency model:
+    /// - _state tracks lifecycle transitions (Active -> DisposeRequested -> Released).
+    /// - HandleGate tracks in-flight operations and enforces the "no new calls after Dispose" rule.
+    /// - SafeHandle is pinned per call via DangerousAddRef to prevent use-after-free while native work runs.
+    /// - If Dispose times out, the last in-flight caller performs the release to avoid leaks.
+    /// </summary>
+    public abstract class SafeHandleWrapper : IDisposable
+    {
+        private static readonly TimeSpan DefaultDisposeTimeout = TimeSpan.FromMilliseconds(50);
+        private const int StateActive = 0;
+        private const int StateDisposeRequested = 1;
+        private const int StateReleased = 2;
+        private readonly HandleGate _gate;
+        private readonly string _ownerName;
+        private int _state;
+        private SafeHandle? _handle;
+
+        protected SafeHandleWrapper(SafeHandle handle, string ownerName)
+        {
+            // Cache ownership info and initialize the gate before any use to avoid racing disposal.
+            _handle = handle ?? throw new ArgumentNullException(nameof(handle));
+            _ownerName = ownerName ?? throw new ArgumentNullException(nameof(ownerName));
+            _gate = new HandleGate(ownerName);
+            // Default to a very short wait when in-flight calls exist; release is deferred to the last caller if needed.
+        }
+
+        protected void UseHandle(Action<IntPtr> action)
+        {
+            // Reuse the generic path to keep add/ref/release in one place.
+            UseHandle<object?>(ptr =>
+            {
+                action(ptr);
+                return null;
+            });
+        }
+
+        protected T UseHandle<T>(Func<IntPtr, T> func)
+        {
+            // Fast reject if dispose was requested.
+            if (System.Threading.Volatile.Read(ref _state) != StateActive)
+            {
+                throw new ObjectDisposedException(_ownerName);
+            }
+
+            // Enter gate so Dispose waits for in-flight native calls.
+            _gate.Enter();
+            bool addedRef = false;
+            SafeHandle? handle = null;
+            try
+            {
+                // Race: Dispose could begin after Enter; GetHandleForUse validates the handle again.
+                handle = GetHandleForUse();
+                // DangerousAddRef pins the SafeHandle so Dispose cannot close it mid-call.
+                handle.DangerousAddRef(ref addedRef);
+                var pointer = handle.DangerousGetHandle();
+                // Validate pointer after AddRef in case handle became invalid between checks.
+                if (pointer == IntPtr.Zero)
+                {
+                    throw new ObjectDisposedException(_ownerName);
+                }
+
+                return func(pointer);
+            }
+            finally
+            {
+                // Always release the DangerousAddRef to avoid leaking the native handle.
+                if (addedRef)
+                {
+                    handle?.DangerousRelease();
+                }
+
+                // Leave gate so Dispose can proceed when the last caller exits.
+                var idle = _gate.Exit();
+                // Race: Dispose may have timed out while we were in-flight.
+                // The last exiting caller performs the native release to avoid leaks.
+                if (idle && System.Threading.Volatile.Read(ref _state) == StateDisposeRequested)
+                {
+                    TryReleaseHandle();
+                }
+            }
+        }
+
+        internal T UseHandleForInterop<T>(Func<IntPtr, T> func)
+        {
+            // Explicit alias for interop-specific call sites.
+            return UseHandle(func);
+        }
+
+        internal void UseHandleForInterop(Action<IntPtr> action)
+        {
+            // Explicit alias for interop-specific call sites.
+            UseHandle(action);
+        }
+
+        private void ThrowIfDisposed()
+        {
+            // Fast check for dispose state so callers fail deterministically.
+            if (System.Threading.Volatile.Read(ref _state) != StateActive)
+            {
+                throw new ObjectDisposedException(_ownerName);
+            }
+
+            // Validate the underlying SafeHandle is still usable; avoids races with release.
+            var handle = _handle;
+            if (handle is null || handle.IsClosed || handle.IsInvalid)
+            {
+                throw new ObjectDisposedException(_ownerName);
+            }
+        }
+
+        private SafeHandle GetHandleForUse()
+        {
+            // Centralized gate for derived classes to grab the handle safely.
+            // This is a second line of defense in case disposal began after the initial state check.
+            var handle = _handle;
+            if (handle is null || handle.IsClosed || handle.IsInvalid)
+            {
+                throw new ObjectDisposedException(_ownerName);
+            }
+            return handle;
+        }
+
+        public void Dispose()
+        {
+            // Only the first caller runs disposal; others become no-ops.
+            if (System.Threading.Interlocked.CompareExchange(ref _state, StateDisposeRequested, StateActive) == StateActive)
+            {
+                // Block new calls and wait briefly if there are in-flight operations.
+                var completed = _gate.TryBeginDispose(DefaultDisposeTimeout, out var hadActive);
+                if (completed)
+                {
+                    // Either no active calls or they drained within the short timeout.
+                    TryReleaseHandle();
+                }
+                else
+                {
+                    // Defer release to the last in-flight caller to avoid leaks without blocking indefinitely.
+                    // Race: if the last in-flight caller already exited, there will be no Exit() to trigger release.
+                    // Re-check active state and release immediately in that case.
+                    if (!hadActive || _gate.IsIdle)
+                    {
+                        TryReleaseHandle();
+                    }
+                }
+            }
+
+            GC.SuppressFinalize(this);
+        }
+
+        private void TryReleaseHandle()
+        {
+            if (System.Threading.Interlocked.CompareExchange(ref _state, StateReleased, StateDisposeRequested) != StateDisposeRequested)
+            {
+                return;
+            }
+
+            // Once released, no caller should be able to observe a valid handle.
+            // SafeHandle.Dispose closes the native resource; null to prevent reuse after dispose.
+            _handle?.Dispose();
+            _handle = null;
+            // Release the wait handle resources after disposal completes.
+            _gate.Dispose();
+        }
+
+        /// <summary>
+        /// Tracks in-flight operations and coordinates disposal.
+        /// </summary>
+        private sealed class HandleGate : IDisposable
+        {
+            private readonly string _ownerName;
+            private readonly System.Threading.ManualResetEventSlim _idle = new(initialState: true);
+            private int _active;
+            private int _disposing;
+
+            internal HandleGate(string ownerName)
+            {
+                _ownerName = ownerName;
+            }
+
+            internal void Enter()
+            {
+                // If disposal already started, reject new work immediately.
+                if (System.Threading.Volatile.Read(ref _disposing) != 0)
+                {
+                    ThrowDisposed();
+                }
+
+                // Track active callers; first one resets idle event.
+                var active = System.Threading.Interlocked.Increment(ref _active);
+                if (active == 1)
+                {
+                    _idle.Reset();
+                }
+
+                // Re-check disposing to handle races where Dispose began after increment.
+                if (System.Threading.Volatile.Read(ref _disposing) != 0)
+                {
+                    Exit();
+                    ThrowDisposed();
+                }
+            }
+
+            internal bool Exit()
+            {
+                // Last caller signals idle so Dispose can continue.
+                if (System.Threading.Interlocked.Decrement(ref _active) == 0)
+                {
+                    _idle.Set();
+                    return true;
+                }
+
+                return false;
+            }
+
+            internal bool IsIdle => System.Threading.Volatile.Read(ref _active) == 0;
+
+            internal bool TryBeginDispose(TimeSpan timeout, out bool hadActive)
+            {
+                // Set disposing flag once; subsequent calls treat as already disposing.
+                if (System.Threading.Interlocked.Exchange(ref _disposing, 1) != 0)
+                {
+                    hadActive = System.Threading.Volatile.Read(ref _active) != 0;
+                    return true;
+                }
+
+                hadActive = System.Threading.Volatile.Read(ref _active) != 0;
+                if (!hadActive)
+                {
+                    // No in-flight callers; disposal can proceed without waiting.
+                    return true;
+                }
+
+                // Wait for active callers to drain; optional timeout avoids blocking forever.
+                if (timeout == System.Threading.Timeout.InfiniteTimeSpan)
+                {
+                    _idle.Wait();
+                    return true;
+                }
+
+                // Race note: callers may finish between the timeout decision and Wait call; Wait handles that safely.
+                return _idle.Wait(timeout);
+            }
+
+            private void ThrowDisposed()
+            {
+                throw new ObjectDisposedException(_ownerName);
+            }
+
+            public void Dispose()
+            {
+                _idle.Dispose();
+            }
+        }
+    }
+}