/**

  * vim: set ts=4 sw=4 tw=99 noet :

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

  * SourceMod

  * Copyright (C) 2004-2008 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_namehashset.h>

 #include <am-string.h>

 #include "common_logic.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

 #define HANDLESYS_MEMUSAGE_MIN_VERSION		3

 /**

  *   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;

 	ke::AutoPtr<ke::AString> name;

 	static inline bool matches(const char *key, const QHandleType *type)

 	{

 		return type->name && type->name->compare(key) == 0;

 	}

 };

 typedef void (HANDLE_REPORTER)(const char *str, ...);

 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(HANDLE_REPORTER rep);

 	/* Bypasses security checks. */

 	Handle_t FastCloneHandle(Handle_t hndl);

 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);

 	Handle_t FastCloneHandle(QHandle *pHandle, unsigned int index);

 	void GetHandleUnchecked(Handle_t hndl, QHandle *& pHandle, unsigned int &index);

 	/**

 	 * 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;

 	NameHashSet<QHandleType *> m_TypeLookup;

 	unsigned int m_TypeTail;

 	unsigned int m_FreeTypes;

 	unsigned int m_HandleTail;

 	unsigned int m_FreeHandles;

 	unsigned int m_HSerial;

 };

 extern HandleSystem g_HandleSys;

 struct AutoHandleRooter

 {

 public:

 	AutoHandleRooter(Handle_t hndl)

 	{

 		if (hndl != BAD_HANDLE)

 			this->hndl = g_HandleSys.FastCloneHandle(hndl);

 		else

 			this->hndl = BAD_HANDLE;

 	}

 	~AutoHandleRooter()

 	{

 		if (hndl != BAD_HANDLE)

 		{

 			HandleSecurity sec(g_pCoreIdent, g_pCoreIdent);

 			g_HandleSys.FreeHandle(hndl, &sec);

 		}

 	}

 private:

 	Handle_t hndl;

 };

 #endif //_INCLUDE_SOURCEMOD_HANDLESYSTEM_H_