kopano-core/common/ECMemStream.h

/*
 * Copyright 2005 - 2016 Zarafa and its licensors
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef ECMEMSTREAM_H
#define ECMEMSTREAM_H

#include <kopano/zcdefs.h>
#include <kopano/ECUnknown.h>
#include <kopano/Util.h>

namespace KC {

/* The ECMemBlock class is basically a random-access block of data that can be
 * read from and written to, expanded and contracted, and has a Commit and Revert
 * function to save and reload data.
 *
 * The commit and revert functions use memory sparingly, as only changed blocks
 * are held in memory.
 */
class ECMemBlock _kc_final : public ECUnknown {
private:
	ECMemBlock(const char *buffer, ULONG len, ULONG flags);
	~ECMemBlock();

public:
	static HRESULT Create(const char *buffer, ULONG len, ULONG flags, ECMemBlock **out);
	virtual HRESULT QueryInterface(REFIID refiid, void **iface) _kc_override;
	virtual HRESULT	ReadAt(ULONG ulPos, ULONG ulLen, char *buffer, ULONG *ulBytesRead);
	virtual HRESULT WriteAt(ULONG ulPos, ULONG ulLen, const char *buffer, ULONG *ulBytesWritten);
	virtual HRESULT Commit();
	virtual HRESULT Revert();
	virtual HRESULT SetSize(ULONG ulSize);
	virtual HRESULT GetSize(ULONG *size) const;

	virtual char *GetBuffer(void) { return lpCurrent; }

private:
	char *lpCurrent = nullptr, *lpOriginal = nullptr;
	ULONG cbCurrent = 0, cbOriginal = 0, cbTotal = 0;
	ULONG	ulFlags;
	ALLOC_WRAP_FRIEND;
};

/* 
 * This is an IStream-compatible wrapper for ECMemBlock
 */
class _kc_export ECMemStream _kc_final : public ECUnknown {
public:
	typedef HRESULT (*CommitFunc)(IStream *lpStream, void *lpParam);
	typedef HRESULT (*DeleteFunc)(void *lpParam); /* Caller's function to remove lpParam data from memory */

private:
	_kc_hidden ECMemStream(char *buffer, ULONG data_len, ULONG flags, CommitFunc, DeleteFunc, void *param);
	_kc_hidden ECMemStream(ECMemBlock *, ULONG flags, CommitFunc, DeleteFunc, void *param);
	_kc_hidden ~ECMemStream(void);

public:
	static  HRESULT	Create(char *buffer, ULONG ulDataLen, ULONG ulFlags, CommitFunc lpCommitFunc, DeleteFunc lpDeleteFunc, void *lpParam, ECMemStream **lppStream);
	_kc_hidden static HRESULT Create(ECMemBlock *, ULONG flags, CommitFunc, DeleteFunc, void *param, ECMemStream **ret);
	virtual ULONG Release(void) _kc_override;
	virtual HRESULT QueryInterface(REFIID refiid, void **iface) _kc_override;
	_kc_hidden virtual HRESULT Read(void *buf, ULONG bytes, ULONG *have_read);
	_kc_hidden virtual HRESULT Write(const void *buf, ULONG bytes, ULONG *have_written);
	_kc_hidden virtual HRESULT Seek(LARGE_INTEGER pos, DWORD origin, ULARGE_INTEGER *newpos);
	_kc_hidden virtual HRESULT SetSize(ULARGE_INTEGER size);
	_kc_hidden virtual HRESULT CopyTo(IStream *, ULARGE_INTEGER cb, ULARGE_INTEGER *have_read, ULARGE_INTEGER *have_written);
	_kc_hidden virtual HRESULT Commit(DWORD commit_flags);
	_kc_hidden virtual HRESULT Revert(void);
	_kc_hidden virtual HRESULT LockRegion(ULARGE_INTEGER offset, ULARGE_INTEGER size, DWORD lock_type);
	_kc_hidden virtual HRESULT UnlockRegion(ULARGE_INTEGER offset, ULARGE_INTEGER size, DWORD lock_type);
	_kc_hidden virtual HRESULT Stat(STATSTG *, DWORD stat_flag);
	_kc_hidden virtual HRESULT Clone(IStream **);
	virtual ULONG GetSize();
	virtual char* GetBuffer();

	class _kc_hidden xStream _kc_final : public IStream {
		#include <kopano/xclsfrag/IUnknown.hpp>
		#include <kopano/xclsfrag/ISequentialStream.hpp>
		#include <kopano/xclsfrag/IStream.hpp>
	} m_xStream;

private:
	ULARGE_INTEGER	liPos;
	ECMemBlock		*lpMemBlock;
	CommitFunc		lpCommitFunc;
	DeleteFunc		lpDeleteFunc;
	void *			lpParam;
	BOOL fDirty = false;
	ULONG			ulFlags;
	ALLOC_WRAP_FRIEND;
};

} /* namespace */

#endif // ECMEMSTREAM_H