forked from mirrors/gecko-dev
75 lines
1.9 KiB
C++
75 lines
1.9 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2; -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef KeyedStackCapturer_h__
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#define KeyedStackCapturer_h__
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#include "Telemetry.h"
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#include "nsString.h"
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#include "nsClassHashtable.h"
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#include "mozilla/Mutex.h"
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#include "CombinedStacks.h"
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struct JSContext;
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namespace mozilla {
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namespace Telemetry {
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/**
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* Allows taking a snapshot of a call stack on demand. Captured stacks are
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* indexed by a string key in a hash table. The stack is only captured Once
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* for each key. Consequent captures with the same key result in incrementing
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* capture counter without re-capturing the stack.
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*/
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class KeyedStackCapturer
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{
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public:
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KeyedStackCapturer()
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: mStackCapturerMutex("Telemetry::StackCapturerMutex")
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{}
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/**
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* Captures a stack for the given key.
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*/
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void Capture(const nsACString& aKey);
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/**
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* Transforms captured stacks into a JS object.
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*/
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NS_IMETHODIMP ReflectCapturedStacks(
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JSContext *cx, JS::MutableHandle<JS::Value> ret);
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/**
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* Resets captured stacks and the information related to them.
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*/
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void Clear();
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private:
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/**
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* Describes how often a stack was captured.
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*/
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struct StackFrequencyInfo {
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// A number of times the stack was captured.
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uint32_t mCount;
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// Index of the stack inside stacks array.
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uint32_t mIndex;
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StackFrequencyInfo(uint32_t aCount, uint32_t aIndex)
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: mCount(aCount)
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, mIndex(aIndex)
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{}
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};
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typedef nsClassHashtable<nsCStringHashKey, StackFrequencyInfo> FrequencyInfoMapType;
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FrequencyInfoMapType mStackInfos;
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CombinedStacks mStacks;
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Mutex mStackCapturerMutex;
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};
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} // namespace Telemetry
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} // namespace mozilla
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#endif // KeyedStackCapturer_h__
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