0ad/source/lib/file/common/trace.h
janwas a859562ea7 improvements and fixes:
- properly differentiate between buffer/offset alignment and length
alignment (relevant since block size has been increased to 256k)
- use VfsPath for most game paths instead of CStr
- clean up timer interface and implementation
- self-tests no longer crash
- file_cache.cpp: fix for the case where allocation fails (prevent
deleter from seeing a null pointer)
- allocators: move all shared_ptr-related stuff to its own component;
add DummySharedPtr
- codec: disable checksums (important for performance at work)
- File: made into an interface class to avoid export problems. not
entirely sure about this..
- vfs_path.h, path.h, os_path.h: proper fix for using
fs::change_extension and similar utility functions with derivatives of
basic_path
- lib_api: automatically link against import lib if building lib/ as a
DLL
- path_util: remove unused functions (this component is deprecated)
- compiler.h: add INLINE
- Xeromyces.cpp: pass PIVFS so that GetXMBPath works in self-test
(should do this mostly everywhere rather than have one singleton g_VFS)

This was SVN commit r5537.
2008-01-07 20:03:19 +00:00

112 lines
2.8 KiB
C++

/**
* =========================================================================
* File : trace.h
* Project : 0 A.D.
* Description : IO event recording
* =========================================================================
*/
// license: GPL; see lib/license.txt
// 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
// stores information about an IO event.
class TraceEntry
{
public:
enum EAction
{
Load = 'L',
Store = 'S',
};
TraceEntry(EAction action, const char* pathname, size_t size);
TraceEntry(const char* textualRepresentation);
~TraceEntry();
EAction Action() const
{
return m_action;
}
const char* Pathname() const
{
return m_pathname;
}
size_t Size() const
{
return m_size;
}
void EncodeAsText(char* text, size_t maxTextChars) 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;
const char* 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 char* pathname, size_t size) = 0;
virtual void NotifyStore(const char* pathname, size_t size) = 0;
/**
* store all entries into a file.
*
* @param osPathname native (absolute) pathname
*
* 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 LibError Store(const char* osPathname) const = 0;
/**
* load entries from file.
*
* @param osPathname native (absolute) pathname
*
* replaces any existing entries.
**/
virtual LibError Load(const char* osPathname) = 0;
virtual const TraceEntry* Entries() const = 0;
virtual size_t NumEntries() const = 0;
};
typedef shared_ptr<ITrace> PITrace;
extern PITrace CreateDummyTrace(size_t maxSize);
extern PITrace CreateTrace(size_t maxSize);
#endif // #ifndef INCLUDED_TRACE