dom/indexedDB/FileInfoManager.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef DOM_INDEXEDDB_FILEINFOMANAGER_H_
   8 #define DOM_INDEXEDDB_FILEINFOMANAGER_H_
   9
  10 #include "mozilla/Attributes.h"
  11 #include "mozilla/Mutex.h"
  12 #include "mozilla/StaticMutex.h"
  13 #include "nsTHashMap.h"
  14 #include "nsHashKeys.h"
  15 #include "nsISupportsImpl.h"
  16 #include "FileInfo.h"
  17 #include "FlippedOnce.h"
  18
  19 namespace mozilla::dom::indexedDB {
  20
  21 class FileInfoManagerBase {
  22  public:
  23   bool Invalidated() const { return mInvalidated; }
  24
  25  protected:
  26   bool AssertValid() const {
  27     if (NS_WARN_IF(Invalidated())) {
  28       MOZ_ASSERT(false);
  29       return false;
  30     }
  31
  32     return true;
  33   }
  34
  35   void Invalidate() { mInvalidated.Flip(); }
  36
  37  private:
  38   FlippedOnce<false> mInvalidated;
  39 };
  40
  41 template <typename FileManager>
  42 class FileInfoManager : public FileInfoManagerBase {
  43  public:
  44   using FileInfoType = FileInfo<FileManager>;
  45   using MutexType = StaticMutex;
  46   using AutoLockType = mozilla::detail::BaseAutoLock<MutexType&>;
  47
  48   [[nodiscard]] SafeRefPtr<FileInfoType> GetFileInfo(int64_t aId) const {
  49     return AcquireFileInfo([this, aId] { return mFileInfos.MaybeGet(aId); });
  50   }
  51
  52   [[nodiscard]] SafeRefPtr<FileInfoType> CreateFileInfo() {
  53     return AcquireFileInfo([this] {
  54       const int64_t id = ++mLastFileId;
  55
  56       auto fileInfo =
  57           MakeNotNull<FileInfoType*>(FileInfoManagerGuard{},
  58                                      SafeRefPtr{static_cast<FileManager*>(this),
  59                                                 AcquireStrongRefFromRawPtr{}},
  60                                      id);
  61
  62       mFileInfos.InsertOrUpdate(id, fileInfo);
  63       return Some(fileInfo);
  64     });
  65   }
  66
  67   void RemoveFileInfo(const int64_t aId, const AutoLockType& aFileMutexLock) {
  68 #ifdef DEBUG
  69     aFileMutexLock.AssertOwns(FileManager::Mutex());
  70 #endif
  71     mFileInfos.Remove(aId);
  72   }
  73
  74   // After calling this method, callers should not call any more methods on this
  75   // class.
  76   virtual nsresult Invalidate() {
  77     AutoLockType lock(FileManager::Mutex());
  78
  79     FileInfoManagerBase::Invalidate();
  80
  81     mFileInfos.RemoveIf([](const auto& iter) {
  82       FileInfoType* info = iter.Data();
  83       MOZ_ASSERT(info);
  84
  85       return !info->LockedClearDBRefs(FileInfoManagerGuard{});
  86     });
  87
  88     return NS_OK;
  89   }
  90
  91   struct FileInfoManagerGuard {
  92     FileInfoManagerGuard() = default;
  93   };
  94
  95  private:
  96   // Runs the given aFileInfoTableOp operation, which must return a FileInfo*,
  97   // under the FileManager lock, acquires a strong reference to the returned
  98   // object under the lock, and returns the strong reference.
  99   template <typename FileInfoTableOp>
 100   [[nodiscard]] SafeRefPtr<FileInfoType> AcquireFileInfo(
 101       const FileInfoTableOp& aFileInfoTableOp) const {
 102     if (!AssertValid()) {
 103       // In release, the assertions are disabled.
 104       return nullptr;
 105     }
 106
 107     // We cannot simply change this to SafeRefPtr<FileInfo>, because
 108     // FileInfo::AddRef also acquires the FileManager::Mutex.
 109     auto fileInfo = [&aFileInfoTableOp]() -> RefPtr<FileInfoType> {
 110       AutoLockType lock(FileManager::Mutex());
 111
 112       const auto maybeFileInfo = aFileInfoTableOp();
 113       if (maybeFileInfo) {
 114         const auto& fileInfo = maybeFileInfo.ref();
 115         fileInfo->LockedAddRef();
 116         return dont_AddRef(fileInfo.get());
 117       }
 118
 119       return {};
 120     }();
 121
 122     return SafeRefPtr{std::move(fileInfo)};
 123   }
 124
 125  protected:
 126 #ifdef DEBUG
 127   ~FileInfoManager() { MOZ_ASSERT(mFileInfos.IsEmpty()); }
 128 #else
 129   ~FileInfoManager() = default;
 130 #endif
 131
 132   // Access to the following fields must be protected by
 133   // FileManager::Mutex()
 134   int64_t mLastFileId = 0;
 135   nsTHashMap<nsUint64HashKey, NotNull<FileInfoType*>> mFileInfos;
 136 };
 137
 138 }  // namespace mozilla::dom::indexedDB
 139
 140 #endif  // DOM_INDEXEDDB_FILEINFOMANAGER_H_