tcpiputils/dnd/src/cache.cpp
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     1 // Copyright (c) 2004-2009 Nokia Corporation and/or its subsidiary(-ies).
       
     2 // All rights reserved.
       
     3 // This component and the accompanying materials are made available
       
     4 // under the terms of "Eclipse Public License v1.0"
       
     5 // which accompanies this distribution, and is available
       
     6 // at the URL "http://www.eclipse.org/legal/epl-v10.html".
       
     7 //
       
     8 // Initial Contributors:
       
     9 // Nokia Corporation - initial contribution.
       
    10 //
       
    11 // Contributors:
       
    12 //
       
    13 // Description:
       
    14 // cache.cpp - the record cache
       
    15 //
       
    16 
       
    17 // This file contains the implementations of the CDndCache object.
       
    18 #include "engine.h"
       
    19 #include "node.h"
       
    20 #include "cache.h"
       
    21 #include <networking/dnd_err.h>
       
    22 #include "inet6log.h"
       
    23 
       
    24 // Cache root node for a specific name space
       
    25 class CDndNameSpace : public CDndNode
       
    26 	{
       
    27 public:
       
    28 	CDndNameSpace(TUint32 aNameSpaceId) : CDndNode(NULL, 0, _L8("")), iNameSpaceId(aNameSpaceId), iState(1) {}
       
    29 	~CDndNameSpace();
       
    30 	const TUint32 iNameSpaceId;	//< The name space ID
       
    31 	TInt iState;				//< Address state (initially = 1)
       
    32 	TInetAddr iAddr;			//< Server Address and port (if any)
       
    33 	CDndNameSpace *iNext;		//< Next name space root
       
    34 	};
       
    35 
       
    36 /**
       
    37 // The destructor has really nothing functional to do.
       
    38 // The precondition for destruct is that ALL nodes and
       
    39 // records under the root node have already been destroyed.
       
    40 */
       
    41 CDndNameSpace::~CDndNameSpace()
       
    42 	{
       
    43 	ASSERT(IsEmpty());
       
    44 	}
       
    45 
       
    46 
       
    47 // CDndCache::CDndCache
       
    48 // ********************
       
    49 CDndCache::CDndCache()
       
    50 	{}
       
    51 
       
    52 
       
    53 // CDndCache::ContstructL
       
    54 // **********************
       
    55 void CDndCache::ConstructL()
       
    56 	{
       
    57 	LOG(Log::Printf(_L("CDndCache::ConstructL() size=%d\r\n"), (TInt)sizeof(*this)));
       
    58 	}
       
    59 
       
    60 
       
    61 // CDndCache::~CDndCache
       
    62 // *********************
       
    63 /**
       
    64 // Delete ALL records, and as a side effect all nodes
       
    65 // (except the roots are freed). And, then delete all
       
    66 // root nodes.
       
    67 //
       
    68 // If there are locked records, which prevent deletion
       
    69 // of all nodes, then cache destructor has been called
       
    70 // incorrectly! (=> ~CDndNameSpace() will panic)
       
    71 */
       
    72 CDndCache::~CDndCache()
       
    73 	{
       
    74 	iRecordList.Cleanup(0);		// Delete all unlocked records
       
    75 	//
       
    76 	// Delete (now supposedly empty) root nodes
       
    77 	//
       
    78 	while (iRootList)
       
    79 		{
       
    80 		CDndNameSpace *ns = iRootList;
       
    81 		iRootList = iRootList->iNext;
       
    82 		delete ns;
       
    83 		}
       
    84 	}
       
    85 
       
    86 // CDndCache::Flush
       
    87 // ****************
       
    88 /**
       
    89 // Empty the cache.
       
    90 */
       
    91 void CDndCache::Flush()
       
    92 	{
       
    93 	iRecordList.Cleanup(0);
       
    94 	}
       
    95 
       
    96 // CDndCache::GetServerAddress
       
    97 // ***************************
       
    98 /**
       
    99 // Get currently known server address for the name space.
       
   100 //
       
   101 // The address state is inially 1 (> 0). It is only changed by the
       
   102 // CDndCache::SetServerAddress .
       
   103 //
       
   104 // If the name-space does not have a root node, the root node
       
   105 // is created by this call (CDndCache::GetNameSpaceL).
       
   106 //
       
   107 // @param	aNameSpace	the name space id
       
   108 // @retval	aAddr		the server address currently associated with the name space
       
   109 // @returns	the state of the returned address as:
       
   110 //	@li	> 0, no address has been set
       
   111 //	@li	= 0, address set
       
   112 //	@li < 0, address set with error state, or
       
   113 //	@li	KErrNoMemory, if needed to create the root node and failed
       
   114 */
       
   115 TInt CDndCache::GetServerAddress(const TUint32 aNameSpace, TInetAddr &aAddr)
       
   116 	{
       
   117 	CDndNameSpace *const ns = GetNameSpace(aNameSpace);
       
   118 	if (ns == NULL)
       
   119 		return KErrNoMemory;
       
   120 
       
   121 	aAddr = ns->iAddr;
       
   122 	return ns->iState;
       
   123 	}
       
   124 
       
   125 // CDndCache::SetServerAddress
       
   126 // ***************************
       
   127 /**
       
   128 // Set the server address/state for the name space.
       
   129 //
       
   130 // If the name-space does not have a root node, the root node
       
   131 // is created by this call (CDndCache::GetNameSpaceL).
       
   132 //
       
   133 // @param	aNameSpace	the name space id
       
   134 // @param	aAddr		the server address to be set
       
   135 // @param	aState		the state of the address
       
   136 */
       
   137 void CDndCache::SetServerAddress(const TUint32 aNameSpace, const TInetAddr &aAddr, const TInt aState)
       
   138 	{
       
   139 	CDndNameSpace *const ns = GetNameSpace(aNameSpace);
       
   140 	if (ns != NULL)
       
   141 		{
       
   142 		ns->iAddr = aAddr;
       
   143 		ns->iState = aState;
       
   144 		}
       
   145 	}
       
   146 
       
   147 // CDndCache::GetNameSpace
       
   148 // ***********************
       
   149 /**
       
   150 // Locate the name space root or try to create it if not found.
       
   151 //
       
   152 // @param	aNameSpace	the name-space id
       
   153 // @returns	the name-space root or NULL, if not found and create
       
   154 //			failed.
       
   155 */
       
   156 CDndNameSpace *CDndCache::GetNameSpace(const TUint32 aNameSpace)
       
   157 	{
       
   158 	CDndNameSpace *ns = iRootList;
       
   159 
       
   160 	// Does a request namespace already exist?
       
   161 	for ( ; ns != NULL; ns = ns->iNext)
       
   162 		if (ns->iNameSpaceId == aNameSpace)
       
   163 			return ns;
       
   164 
       
   165 	// Does not exist, a new namespace needed, create a new root
       
   166 	ns = new CDndNameSpace(aNameSpace);
       
   167 	if (ns)
       
   168 		{
       
   169 		ns->iNext = iRootList;
       
   170 		iRootList = ns;
       
   171 		}
       
   172 	return ns;
       
   173 	}
       
   174 
       
   175 
       
   176 // CDndCache::FindL
       
   177 // ****************
       
   178 /**
       
   179 // Find record from the cache.
       
   180 //
       
   181 // Finds the record from the cache which 
       
   182 // matches the name, type and class. If it has expired, it is invalidated
       
   183 // and returned. If no such record exists, one new record is inserted and
       
   184 // returned.
       
   185 //
       
   186 // If the name-space does not have a root node, the root node
       
   187 // is created by this call (CDndCache::GetNameSpaceL).
       
   188 //
       
   189 // @param	aNameSpace
       
   190 //		the name-space id. If ZERO, only search is performed
       
   191 //		across all currently existing name-spaces. No new
       
   192 //		state is created.
       
   193 // @param	aName
       
   194 //		the fully qualified domain-name which owns the record (dotted format)			
       
   195 // @param	aType
       
   196 //		the record type
       
   197 // @param	aClass
       
   198 //		the record class
       
   199 // @param	aReqTime
       
   200 //		the time of the request. This is used to detect records whose TTL
       
   201 //		is expired
       
   202 // @returns
       
   203 //		always a non-NULL pointer to the record matching (aNameSpace,aName,aType,aClass). The FindL
       
   204 //		will create the necessary node structures, if they do not exist before the call. If the
       
   205 //		record didn't exist before, the initial state of the new record is "Invalid".
       
   206 // @exception	KErrNoMemory
       
   207 //		the main potential reason for FindL to fail (not enough memory to create the objects)
       
   208 // @exception	KErrDndNoRecord
       
   209 //		can occur only when called with aNameSpace == 0, and the record does not exist.
       
   210 */
       
   211 CDndRecord * CDndCache::FindL(const TUint32 aNameSpace, const TDesC8 &aName, const EDnsQType aType, const EDnsQClass aClass, 
       
   212 								const TTime &aReqTime)
       
   213 	{
       
   214 	CDndRecord *record = NULL;
       
   215 
       
   216 	if (aNameSpace == 0)
       
   217 		{
       
   218 		// If no name space is specified, then just search for match, never add record
       
   219 		for (CDndNameSpace *ns = iRootList; ; ns = ns->iNext)
       
   220 			{
       
   221 			if (ns == NULL)
       
   222 				User::Leave(KErrDndNoRecord);
       
   223 			record = ns->FindL(aName, FALSE, aType, aClass, iRecordList, aReqTime);
       
   224 			if (record)
       
   225 				break;
       
   226 			}
       
   227 		// record != NULL here, ALWAYS!
       
   228 		}
       
   229 	else
       
   230 		{
       
   231 		// When namespace is defined, always create the record and other necessary structures
       
   232 		// if neeeded.
       
   233 		//
       
   234 		iRecordList.Cleanup(KDndMaxRecords);
       
   235 		// Locate or create the name-space root
       
   236 		CDndNameSpace *const ns = GetNameSpace(aNameSpace);
       
   237 		if (ns == NULL)
       
   238 			User::Leave(KErrNoMemory);
       
   239 		// Locate (or create) the matching record
       
   240 		record = ns->FindL(aName, TRUE, aType, aClass, iRecordList, aReqTime);
       
   241 		// record != NULL here ALWAYS!
       
   242 		}
       
   243 
       
   244 	record->HitLRU();
       
   245 	return record;
       
   246 	}
       
   247 
       
   248 
       
   249 #ifdef _LOG
       
   250 // CDndCache::Dump
       
   251 // ***************
       
   252 /**
       
   253 // Print out the entire cache (for DEBUG only)
       
   254 */
       
   255 void CDndCache::Dump(CDndEngine &aControl)
       
   256 	{
       
   257 	if (!iRootList)
       
   258 		aControl.ShowText(_L("No cache in the system"));
       
   259 	else
       
   260 		for (CDndNameSpace *ns = iRootList; ns != NULL; ns = ns->iNext)
       
   261 			ns->Print(aControl);
       
   262 	}
       
   263 #endif