/**

 * vim: set ts=4 :

 * =============================================================================

 * SourceMod

 * Copyright (C) 2004-2007 AlliedModders LLC.  All rights reserved.

 * =============================================================================

 *

 * This program is free software; you can redistribute it and/or modify it under

 * the terms of the GNU General Public License, version 3.0, 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 General Public License for more

 * details.

 *

 * You should have received a copy of the GNU General Public License along with

 * this program.  If not, see <http://www.gnu.org/licenses/>.

 *

 * As a special exception, AlliedModders LLC gives you permission to link the

 * code of this program (as well as its derivative works) to "Half-Life 2," the

 * "Source Engine," the "SourcePawn JIT," and any Game MODs that run on software

 * by the Valve Corporation.  You must obey the GNU General Public License in

 * all respects for all other code used.  Additionally, AlliedModders LLC grants

 * this exception to all derivative works.  AlliedModders LLC defines further

 * exceptions, found in LICENSE.txt (as of this writing, version JULY-31-2007),

 * or <http://www.sourcemod.net/license.php>.

 *

 * Version: $Id$

 */

#ifndef _INCLUDE_SOURCEMOD_HANDLESYSTEM_H_

#define _INCLUDE_SOURCEMOD_HANDLESYSTEM_H_

#include <IHandleSys.h>

#include <stdio.h>

#include "sm_globals.h"

#include "sm_trie.h"

#include "sourcemod.h"

#include "sm_memtable.h"

#define HANDLESYS_MAX_HANDLES		(1<<14)

#define HANDLESYS_MAX_TYPES			(1<<9)

#define HANDLESYS_MAX_SUBTYPES		0xF

#define HANDLESYS_SUBTYPE_MASK		0xF

#define HANDLESYS_TYPEARRAY_SIZE	(HANDLESYS_MAX_TYPES * (HANDLESYS_MAX_SUBTYPES + 1))

#define HANDLESYS_MAX_SERIALS		0xFFFF

#define HANDLESYS_SERIAL_MASK		0xFFFF0000

#define HANDLESYS_HANDLE_MASK		0x0000FFFF

/**

 *   The QHandle is a nasty structure that compacts the handle system into a big vector.

 * The members of the vector each encapsulate one Handle, however, they also act as nodes

 * in an inlined linked list and an inlined vector.

 *

 *   The first of these lists is the 'freeID' list.  Each node from 1 to N (where N

 * is the number of free nodes) has a 'freeID' that specifies a free Handle ID.  This

 * is a quick hack to get around allocating a second base vector.

 *

 *   The second vector is the identity linked list.  An identity has its own handle, so

 * these handles are used as sentinel nodes for index linking.  They point to the first and last

 * index into the handle array.  Each subsequent Handle who is owned by that identity is mapped into

 * that list.  This lets owning identities be unloaded in O(n) time.

 *

 *   Eventually, there may be a third list for type chains.

 */

enum HandleSet

{

	HandleSet_None = 0,

	HandleSet_Used,			/* The Handle is in use */

	HandleSet_Freed,		/* The "master" Handle of a clone chain is freed */

	HandleSet_Identity,		/* The Handle is a special identity */

};

struct QHandle

{

	HandleType_t type;			/* Handle type */

	void *object;				/* Unmaintained object pointer */

	IdentityToken_t *owner;		/* Identity of object which owns this */

	unsigned int serial;		/* Serial no. for sanity checking */

	unsigned int refcount;		/* Reference count for safe destruction */

	unsigned int clone;			/* If non-zero, this is our cloned parent index */

	HandleSet set;				/* Information about the handle's state */

	bool access_special;		/* Whether or not access rules are special or type-derived */

	bool is_destroying;			/* Whether or not the handle is being destroyed */

	HandleAccess sec;			/* Security rules */

	/* The following variables are unrelated to the Handle array, and used 

	 * as an inlined chain of information */

	unsigned int freeID;		/* ID of a free handle in the free handle chain */

	/* Indexes into the handle array for owner membership.

	 * For identity roots, these are treated as the head/tail. */

	unsigned int ch_prev;		/* chained previous handle */

	unsigned int ch_next;		/* chained next handle */

};

struct QHandleType

{

	IHandleTypeDispatch *dispatch;

	unsigned int freeID;

	unsigned int children;

	TypeAccess typeSec;

	HandleAccess hndlSec;

	unsigned int opened;

	int nameIdx;

};

class HandleSystem : 

	public IHandleSys

{

	friend HandleError IdentityHandle(IdentityToken_t *token, unsigned int *index);

	friend class ShareSystem;

public:

	HandleSystem();

	~HandleSystem();

public: //IHandleSystem

	HandleType_t CreateType(const char *name,

		IHandleTypeDispatch *dispatch,

		HandleType_t parent,

		const TypeAccess *typeAccess,

		const HandleAccess *hndlAccess,

		IdentityToken_t *ident,

		HandleError *err);

	bool RemoveType(HandleType_t type, IdentityToken_t *ident);

	bool FindHandleType(const char *name, HandleType_t *type);

	Handle_t CreateHandle(HandleType_t type, 

		void *object,

		IdentityToken_t *owner,

		IdentityToken_t *ident,

		HandleError *err);

	HandleError FreeHandle(Handle_t handle, const HandleSecurity *pSecurity);

	HandleError CloneHandle(Handle_t handle, 

		Handle_t *newhandle, 

		IdentityToken_t *newOwner,

		const HandleSecurity *pSecurity);

	HandleError ReadHandle(Handle_t handle, 

		HandleType_t type, 

		const HandleSecurity *pSecurity,

		void **object);

	bool InitAccessDefaults(TypeAccess *pTypeAccess, HandleAccess *pHandleAccess);

	bool TypeCheck(HandleType_t intype, HandleType_t outtype);

	virtual Handle_t CreateHandleEx(HandleType_t type, 

		void *object,

		const HandleSecurity *pSec,

		const HandleAccess *pAccess,

		HandleError *err);

	void Dump(FILE *fp);

protected:

	/**

	 * Decodes a handle with sanity and security checking.

	 */

	HandleError GetHandle(Handle_t handle, 

						  IdentityToken_t *ident, 

						  QHandle **pHandle, 

						  unsigned int *index,

						  bool ignoreFree=false);

	/**

	 * Creates a basic handle and sets its reference count to 1.

	 * Does not do any type or security checking.

	 */

	HandleError MakePrimHandle(HandleType_t type, 

							   QHandle **pHandle, 

							   unsigned int *index, 

							   HandleType_t *handle,

							   IdentityToken_t *owner,

							   bool identity=false);

	/**

	 * Frees a primitive handle.  Does no object freeing, only reference count, bookkeeping, 

	 * and linked list maintenance.

	 * If used on an Identity handle, destroys all Handles under that identity.

	 */

	void ReleasePrimHandle(unsigned int index);

	/**

	 * Sets the security owner of a type.

	 */

	void SetTypeSecurityOwner(HandleType_t type, IdentityToken_t *pToken);

	/**

	 * Helper function to check access rights.

	 */

	bool CheckAccess(QHandle *pHandle, HandleAccessRight right, const HandleSecurity *pSecurity);

	/** 

	 * Some wrappers for internal functions, so we can pass indexes instead of encoded handles.

	 */

	HandleError FreeHandle(QHandle *pHandle, unsigned int index);

	void UnlinkHandleFromOwner(QHandle *pHandle, unsigned int index);

	HandleError CloneHandle(QHandle *pHandle, unsigned int index, Handle_t *newhandle, IdentityToken_t *newOwner);

	Handle_t CreateHandleInt(HandleType_t type, void *object, const HandleSecurity *pSec, HandleError *err, const HandleAccess *pAccess, bool identity);

	bool TryAndFreeSomeHandles();

	HandleError TryAllocHandle(unsigned int *handle);

private:

	QHandle *m_Handles;

	QHandleType *m_Types;

	Trie *m_TypeLookup;

	unsigned int m_TypeTail;

	unsigned int m_FreeTypes;

	unsigned int m_HandleTail;

	unsigned int m_FreeHandles;

	unsigned int m_HSerial;

	BaseStringTable *m_strtab;

};

extern HandleSystem g_HandleSys;

#endif //_INCLUDE_SOURCEMOD_HANDLESYSTEM_H_