1 files changed, 131 insertions, 0 deletions
diff --git a/dom/indexedDB/FileManagerBase.h b/dom/indexedDB/FileManagerBase.h
new file mode 100644
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+++ b/dom/indexedDB/FileManagerBase.h
@@ -0,0 +1,131 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_indexeddb_filemanagerbase_h__
+#define mozilla_dom_indexeddb_filemanagerbase_h__
+
+#include "mozilla/Attributes.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/StaticMutex.h"
+#include "nsDataHashtable.h"
+#include "nsHashKeys.h"
+#include "nsISupportsImpl.h"
+#include "FileInfoT.h"
+#include "FlippedOnce.h"
+
+namespace mozilla {
+namespace dom {
+namespace indexedDB {
+
+template <typename FileManager>
+class FileManagerBase {
+ public:
+  using FileInfo = FileInfoT<FileManager>;
+  using MutexType = StaticMutex;
+  using AutoLock = mozilla::detail::BaseAutoLock<MutexType&>;
+
+  [[nodiscard]] SafeRefPtr<FileInfo> GetFileInfo(int64_t aId) const {
+    return AcquireFileInfo([this, aId] { return mFileInfos.Get(aId); });
+  }
+
+  [[nodiscard]] SafeRefPtr<FileInfo> CreateFileInfo() {
+    return AcquireFileInfo([this] {
+      const int64_t id = ++mLastFileId;
+
+      FileInfo* fileInfo =
+          new FileInfo(FileManagerGuard{},
+                       SafeRefPtr{static_cast<FileManager*>(this),
+                                  AcquireStrongRefFromRawPtr{}},
+                       id);
+
+      mFileInfos.Put(id, fileInfo);
+      return fileInfo;
+    });
+  }
+
+  void RemoveFileInfo(const int64_t aId, const AutoLock& aFileMutexLock) {
+#ifdef DEBUG
+    aFileMutexLock.AssertOwns(FileManager::Mutex());
+#endif
+    mFileInfos.Remove(aId);
+  }
+
+  nsresult Invalidate() {
+    AutoLock lock(FileManager::Mutex());
+
+    mInvalidated.Flip();
+
+    mFileInfos.RemoveIf([](const auto& iter) {
+      FileInfo* info = iter.Data();
+      MOZ_ASSERT(info);
+
+      return !info->LockedClearDBRefs(FileManagerGuard{});
+    });
+
+    return NS_OK;
+  }
+
+  bool Invalidated() const { return mInvalidated; }
+
+  class FileManagerGuard {
+    FileManagerGuard() = default;
+  };
+
+ private:
+  // Runs the given aFileInfoTableOp operation, which must return a FileInfo*,
+  // under the file manager lock, acquires a strong reference to the returned
+  // object under the lock, and returns the strong reference.
+  template <typename FileInfoTableOp>
+  [[nodiscard]] SafeRefPtr<FileInfo> AcquireFileInfo(
+      const FileInfoTableOp& aFileInfoTableOp) const {
+    if (!AssertValid()) {
+      // In release, the assertions are disabled.
+      return nullptr;
+    }
+
+    // We cannot simply change this to SafeRefPtr<FileInfo>, because
+    // FileInfo::AddRef also acquires the FileManager::Mutex.
+    already_AddRefed<FileInfo> fileInfo = [&aFileInfoTableOp] {
+      AutoLock lock(FileManager::Mutex());
+      FileInfo* fileInfo = aFileInfoTableOp();
+      if (fileInfo) {
+        fileInfo->LockedAddRef();
+      }
+      return dont_AddRef(fileInfo);
+    }();
+
+    return SafeRefPtr{RefPtr<FileInfo>{fileInfo}};
+  }
+
+ protected:
+  bool AssertValid() const {
+    if (NS_WARN_IF(static_cast<const FileManager*>(this)->Invalidated())) {
+      MOZ_ASSERT(false);
+      return false;
+    }
+
+    return true;
+  }
+
+#ifdef DEBUG
+  ~FileManagerBase() { MOZ_ASSERT(mFileInfos.IsEmpty()); }
+#else
+  ~FileManagerBase() = default;
+#endif
+
+  // Access to the following fields must be protected by
+  // FileManager::Mutex()
+  int64_t mLastFileId = 0;
+  nsDataHashtable<nsUint64HashKey, FileInfo*> mFileInfos;
+
+  FlippedOnce<false> mInvalidated;
+};
+
+}  // namespace indexedDB
+}  // namespace dom
+}  // namespace mozilla
+
+#endif  // mozilla_dom_indexeddb_filemanagerbase_h__