How to Create a Direct File Store

Article Metadata

---

Article

Created: vasant21 (18 May 2007)

Last edited: hamishwillee (23 Jul 2012)

#include <s32file.h>
Link Againts : estor.lib

Creating a Persistent Direct File Store

// The call to ReplaceLC() will create the file if it does not exist, otherwise
//it will replace any existing file.
 
CFileStore* store = CDirectFileStore::ReplaceLC(aFs,aFileName,EFileWrite);
 
//set the store’s type 
 
store->SetTypeL(TUidType(KDirectFileStoreLayoutUid,KUidAppDllDoc,aAppUid));
 
// Create a stream dictionarary
 
CStreamDictionary* dictionary = CStreamDictionary::NewLC();
 
// We then Create, write and close a stream 
 
RStoreWriteStream stream;
 
TStreamId id = stream.CreateLC(*store);
 
TInt16 i = 0x1234;
 
stream << i;
 
stream.CommitL();
 
CleanupStack::PopAndDestroy(); // stream
 
// you must use an instance of RStoreWriteStream, whose CreateL() and
// CreateLC() functions return a TStreamId. Once writing the stream is
// complete, you need to add an entry to the stream dictionary, making an
// association between the stream ID and an externally known UID:
 
 
dictionary->AssignL(aAppUid,id);
 
// create a stream to contain the stream dictionary,
// and mark it as being the root stream
 
RStoreWriteStream rootStream;
 
TStreamId rootId = rootStream.CreateLC(*store);
 
rootStream << *dictionary;
 
// commit all the changes made to the store and then to free its resource
// rootStream.CommitL();
 
 
CleanupStack::PopAndDestroy(); // rootStream
 
CleanupStack::PopAndDestroy(); // dictionary
 
store->SetRootL(rootId);
 
store->CommitL();
 
CleanupStack::PopAndDestroy(); // store

Reading a Persistent Store

CFileStore* store = CDirectFileStore::OpenLC(aFs,aFileName,EFileRead);
 
CStreamDictionary* dictionary = CStreamDictionary::NewLC();
 
RStoreReadStream rootStream;
 
rootStream.OpenLC(*store, store->Root());
 
rootStream >> *dictionary;
 
CleanupStack::PopAndDestroy(); // rootStream
 
TStreamId id = dictionary->At(aAppUid);
 
CleanupStack::PopAndDestroy(); // dictionary
 
RStoreReadStream stream;
 
stream.OpenLC(*store, id);
 
TInt16 j;
 
stream >> j;
 
CleanupStack::PopAndDestroy(); // stream
 
CleanupStack::PopAndDestroy(); // store