toolkit/components/telemetry/other/CombinedStacks.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef CombinedStacks_h__
   7 #define CombinedStacks_h__
   8
   9 #include <vector>
  10
  11 #include "ipc/IPCMessageUtils.h"
  12 #include "ProcessedStack.h"
  13
  14 class JSObject;
  15 struct JSContext;
  16
  17 namespace mozilla {
  18 namespace Telemetry {
  19
  20 /**
  21  * This class is conceptually a list of ProcessedStack objects, but it
  22  * represents them more efficiently by keeping a single global list of modules.
  23  */
  24 class CombinedStacks {
  25  public:
  26   explicit CombinedStacks();
  27   explicit CombinedStacks(size_t aMaxStacksCount);
  28
  29   CombinedStacks(CombinedStacks&&) = default;
  30   CombinedStacks& operator=(CombinedStacks&&) = default;
  31
  32   void Swap(CombinedStacks& aOther);
  33
  34   typedef std::vector<Telemetry::ProcessedStack::Frame> Stack;
  35   const Telemetry::ProcessedStack::Module& GetModule(unsigned aIndex) const;
  36   size_t GetModuleCount() const;
  37   const Stack& GetStack(unsigned aIndex) const;
  38   size_t AddStack(const Telemetry::ProcessedStack& aStack);
  39   void AddStacks(const CombinedStacks& aStacks);
  40   size_t GetStackCount() const;
  41   size_t SizeOfExcludingThis() const;
  42   void RemoveStack(unsigned aIndex);
  43   size_t GetMaxStacksCount() const;
  44
  45   /** Clears the contents of vectors and resets the index. */
  46   void Clear();
  47
  48  private:
  49   std::vector<Telemetry::ProcessedStack::Module> mModules;
  50   // A circular buffer to hold the stacks.
  51   std::vector<Stack> mStacks;
  52   // The index of the next buffer element to write to in mStacks.
  53   size_t mNextIndex;
  54   // The maximum number of stacks to keep in the CombinedStacks object.
  55   size_t mMaxStacksCount;
  56
  57   void AddFrame(
  58       size_t aStackIndex, const ProcessedStack::Frame& aFrame,
  59       const std::function<const ProcessedStack::Module&(int)>& aModuleGetter);
  60
  61   friend struct ::IPC::ParamTraits<CombinedStacks>;
  62 };
  63
  64 /**
  65  * Creates a JSON representation of given combined stacks object.
  66  */
  67 JSObject* CreateJSStackObject(JSContext* cx, const CombinedStacks& stacks);
  68
  69 }  // namespace Telemetry
  70 }  // namespace mozilla
  71
  72 namespace IPC {
  73
  74 template <>
  75 struct ParamTraits<mozilla::Telemetry::CombinedStacks> {
  76   typedef mozilla::Telemetry::CombinedStacks paramType;
  77
  78   static void Write(MessageWriter* aWriter, const paramType& aParam) {
  79     WriteParam(aWriter, aParam.mModules);
  80     WriteParam(aWriter, aParam.mStacks);
  81     WriteParam(aWriter, aParam.mNextIndex);
  82     WriteParam(aWriter, aParam.mMaxStacksCount);
  83   }
  84
  85   static bool Read(MessageReader* aReader, paramType* aResult) {
  86     if (!ReadParam(aReader, &aResult->mModules)) {
  87       return false;
  88     }
  89
  90     if (!ReadParam(aReader, &aResult->mStacks)) {
  91       return false;
  92     }
  93
  94     if (!ReadParam(aReader, &aResult->mNextIndex)) {
  95       return false;
  96     }
  97
  98     if (!ReadParam(aReader, &aResult->mMaxStacksCount)) {
  99       return false;
 100     }
 101
 102     return true;
 103   }
 104 };
 105
 106 }  // namespace IPC
 107
 108 #endif  // CombinedStacks_h__