dom/quota/UsageInfo.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 file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_dom_quota_usageinfo_h__
   8 #define mozilla_dom_quota_usageinfo_h__
   9
  10 #include <cstdint>
  11 #include <utility>
  12 #include "mozilla/CheckedInt.h"
  13 #include "mozilla/Maybe.h"
  14
  15 namespace mozilla::dom::quota {
  16
  17 enum struct UsageKind { Database, File };
  18
  19 namespace detail {
  20 inline void AddCapped(Maybe<uint64_t>& aValue, const Maybe<uint64_t> aDelta) {
  21   if (aDelta.isSome()) {
  22     CheckedUint64 value = aValue.valueOr(0);
  23
  24     value += aDelta.value();
  25
  26     aValue = Some(value.isValid() ? value.value() : UINT64_MAX);
  27   }
  28 }
  29
  30 template <UsageKind Kind>
  31 struct Usage {
  32   explicit Usage(Maybe<uint64_t> aValue = Nothing{}) : mValue(aValue) {}
  33
  34   Maybe<uint64_t> GetValue() const { return mValue; }
  35
  36   Usage& operator+=(const Usage aDelta) {
  37     AddCapped(mValue, aDelta.mValue);
  38
  39     return *this;
  40   }
  41
  42   Usage operator+(const Usage aDelta) const {
  43     Usage res = *this;
  44     res += aDelta;
  45     return res;
  46   }
  47
  48  private:
  49   Maybe<uint64_t> mValue;
  50 };
  51 }  // namespace detail
  52
  53 using DatabaseUsageType = detail::Usage<UsageKind::Database>;
  54 using FileUsageType = detail::Usage<UsageKind::File>;
  55
  56 class UsageInfo final {
  57  public:
  58   UsageInfo() = default;
  59
  60   explicit UsageInfo(const DatabaseUsageType aUsage) : mDatabaseUsage(aUsage) {}
  61
  62   explicit UsageInfo(const FileUsageType aUsage) : mFileUsage(aUsage) {}
  63
  64   UsageInfo operator+(const UsageInfo& aUsageInfo) {
  65     UsageInfo res = *this;
  66     res += aUsageInfo;
  67     return res;
  68   }
  69
  70   UsageInfo& operator+=(const UsageInfo& aUsageInfo) {
  71     mDatabaseUsage += aUsageInfo.mDatabaseUsage;
  72     mFileUsage += aUsageInfo.mFileUsage;
  73     return *this;
  74   }
  75
  76   UsageInfo& operator+=(const DatabaseUsageType aUsage) {
  77     mDatabaseUsage += aUsage;
  78     return *this;
  79   }
  80
  81   UsageInfo& operator+=(const FileUsageType aUsage) {
  82     mFileUsage += aUsage;
  83     return *this;
  84   }
  85
  86   Maybe<uint64_t> DatabaseUsage() const { return mDatabaseUsage.GetValue(); }
  87
  88   Maybe<uint64_t> FileUsage() const { return mFileUsage.GetValue(); }
  89
  90   Maybe<uint64_t> TotalUsage() const {
  91     Maybe<uint64_t> res = mDatabaseUsage.GetValue();
  92     detail::AddCapped(res, FileUsage());
  93     return res;
  94   }
  95
  96  private:
  97   DatabaseUsageType mDatabaseUsage;
  98   FileUsageType mFileUsage;
  99 };
 100
 101 }  // namespace mozilla::dom::quota
 102
 103 #endif  // mozilla_dom_quota_usageinfo_h__