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/* Copyright (C) 2025 Wildfire Games.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/*
* IO event recording
*/
// traces are useful for determining the optimal ordering of archived files
// and can also serve as a repeatable IO benchmark.
// note: since FileContents are smart pointers, the trace can't easily
// be notified when they are released (relevant for cache simulation).
// we have to assume that users process one file at a time -- as they
// should.
#ifndef INCLUDED_TRACE
#define INCLUDED_TRACE
#include "lib/os_path.h"
#include "lib/path.h"
#include "lib/status.h"
#include <cstddef>
#include <memory>
#include <string>
// stores information about an IO event.
class TraceEntry
{
public:
enum EAction
{
Load = 'L',
Store = 'S'
};
TraceEntry(EAction action, const Path& pathname, size_t size);
TraceEntry(const std::wstring& text);
EAction Action() const
{
return m_action;
}
const Path& Pathname() const
{
return m_pathname;
}
size_t Size() const
{
return m_size;
}
std::wstring EncodeAsText() const;
private:
// note: keep an eye on the class size because all instances are kept
// in memory (see ITrace)
// time (as returned by timer_Time) after the operation completes.
// rationale: when loading, the VFS doesn't know file size until
// querying the cache or retrieving file information.
float m_timestamp;
EAction m_action;
Path m_pathname;
// size of file.
// rationale: other applications using this trace format might not
// have access to the VFS and its file information.
size_t m_size;
};
// note: to avoid interfering with measurements, this trace container
// does not cause any IOs (except of course in Load/Store)
struct ITrace
{
virtual ~ITrace();
virtual void NotifyLoad(const Path& pathname, size_t size) = 0;
virtual void NotifyStore(const Path& pathname, size_t size) = 0;
/**
* store all entries into a file.
*
* @param pathname (native, absolute)
*
* note: the file format is text-based to allow human inspection and
* because storing filename strings in a binary format would be a
* bit awkward.
**/
virtual Status Store(const OsPath& pathname) const = 0;
/**
* load entries from file.
*
* @param pathname (native, absolute)
*
* replaces any existing entries.
**/
virtual Status Load(const OsPath& pathname) = 0;
virtual const TraceEntry* Entries() const = 0;
virtual size_t NumEntries() const = 0;
};
typedef std::shared_ptr<ITrace> PITrace;
extern PITrace CreateDummyTrace(size_t maxSize);
extern PITrace CreateTrace(size_t maxSize);
#endif // #ifndef INCLUDED_TRACE
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