/*++

Copyright (c) 1999  Microsoft Corporation

Abstract:

    @doc
    @module Writer.h | Declaration of Writer
    @end

Author:

    Adi Oltean  [aoltean]  08/18/1999

TBD:

    Add comments.

Revision History:

    Name        Date        Comments
    aoltean     08/18/1999  Created
    brianb      05/03/2000  Changed for new security model
    brianb      05/09/2000  fix problem with autolocks
    mikejohn    06/23/2000  Add connection for SetWriterFailure()
--*/


#ifndef __CVSS_WRITER_IMPL_H_
#define __CVSS_WRITER_IMPL_H_


// forward declarations
class CVssWriterImplStateMachine;
class CVssCreateWriterMetadata;
class CVssWriterComponents;
class IVssWriterComponentsInt;

////////////////////////////////////////////////////////////////////////
//  Standard foo for file name aliasing.  This code block must be after
//  all includes of VSS header files.
//
#ifdef VSS_FILE_ALIAS
#undef VSS_FILE_ALIAS
#endif
#define VSS_FILE_ALIAS "INCWRMPH"
//
////////////////////////////////////////////////////////////////////////


// implementation class for writers
class IVssWriterImpl : public IVssWriter
    {
public:
    // initialize writer
    virtual void Initialize
        (
        VSS_ID writerId,
        LPCWSTR wszWriterName,
        VSS_USAGE_TYPE ut,
        VSS_SOURCE_TYPE st,
        VSS_APPLICATION_LEVEL nLevel,
        DWORD dwTimeout
        ) = 0;

    // subscribe to events
    virtual void Subscribe
        (
        ) = 0;

    // unsubscribe from events
    virtual void Unsubscribe
        (
        ) = 0;

    virtual void Uninitialize
        (
        ) = 0;

    // get array of volume names
    virtual LPCWSTR *GetCurrentVolumeArray() const = 0;

    // get # of volumes in volume array
    virtual UINT GetCurrentVolumeCount() const = 0;

    // get the snapshot device name for a particular volume
    virtual HRESULT GetSnapshotDeviceName
        (
        LPCWSTR wszOriginalVolume,
        LPCWSTR* ppwszSnapshotDevice
        ) const = 0;

    // get id of snapshot set
    virtual VSS_ID GetCurrentSnapshotSetId() const = 0;

    // get the current backup context
    virtual LONG GetContext() const = 0;
	
    // determine which Freeze event writer responds to
    virtual VSS_APPLICATION_LEVEL GetCurrentLevel() const = 0;

    // determine if path is included in the snapshot
    virtual bool IsPathAffected(IN LPCWSTR wszPath) const = 0;

    // determine if bootable state is backed up
    virtual bool IsBootableSystemStateBackedUp() const = 0;

    // determine if the backup application is selecting components
    virtual bool AreComponentsSelected() const = 0;

    // determine the backup type for the backup
    virtual VSS_BACKUP_TYPE GetBackupType() const = 0;

    // determine the type of restore
    virtual VSS_RESTORE_TYPE GetRestoreType() const = 0;
	
    // let writer pass back indication of reason for failure
    virtual HRESULT SetWriterFailure(HRESULT hr) = 0;

    // determine if requestor support partial file backups
    virtual bool IsPartialFileSupportEnabled() const = 0;
    };


// writer state structure.  encapsulates state of this writer for a
// specific snapshot set
typedef struct _VSWRITER_STATE
    {
    // snapshot id
    VSS_ID m_idSnapshotSet;

    // writer state
    volatile VSS_WRITER_STATE m_state;

    // reason for writer failure
    volatile HRESULT m_hrWriterFailure;

    // are we currently in an operation
    volatile bool m_bInOperation;

    // current operation
    volatile VSS_OPERATION m_currentOperation;

    } VSWRITER_STATE;






class CVssWriterState;


//////////////////////////////////////////////////////////////////////////
// Auto diag class


class CVssAutoDiagLogger
{
public:

	// Constructor
	CVssAutoDiagLogger( 
		IN CVssWriterState & state,
		IN DWORD dwEventID,
		IN VSS_ID ssid = GUID_NULL,
		IN DWORD dwEventFlags = 0
		);
	
	// Constructor
	CVssAutoDiagLogger( 
		IN CVssWriterState & state,
		IN DWORD dwEventID,
		IN WCHAR* pwszSSID,
		IN DWORD dwEventFlags = 0
		);

	// Destructor
	~CVssAutoDiagLogger();

	
private:
	CVssAutoDiagLogger( const CVssAutoDiagLogger& );
	void operator = ( const CVssAutoDiagLogger& );

	CVssWriterState &		m_state;
	DWORD					m_dwEventID;
	DWORD					m_dwEventFlags;
	VSS_ID					m_ssid;
};



//////////////////////////////////////////////////////////////////////////
// writer state class.  encapsulates all aspects of a writer's state


class CVssWriterState
    {
private:
    CVssWriterState();
	CVssWriterState(const CVssWriterState&);
    
public:
    // constructors and destructors
    CVssWriterState( IN	CVssDiag& diag );

    // initialization function
    void Initialize()
        {
        m_cs.Init();
        }


    // get state for a snapshot set
    void GetStateForSnapshot
        (
        IN const VSS_ID &idSnapshot,
        OUT VSWRITER_STATE &state
        );

    // initialize a snapshot
    void InitializeCurrentState(IN const VSS_ID &idSnapshot);

    // indicate we are in an operation
    void SetInOperation(VSS_OPERATION operation)
        {
	    CVssSafeAutomaticLock lock(m_cs);
	    
        m_currentState.m_bInOperation = true;
        m_currentState.m_currentOperation = operation;
        }

    // are we in a restore operation
    bool IsInRestore()
        {
        return (m_currentState.m_currentOperation == VSS_IN_PRERESTORE ||
                     m_currentState.m_currentOperation == VSS_IN_POSTRESTORE);
        }

    // indicate that we are leaving an operation
    void ExitOperation()
        {
		CVssSafeAutomaticLock lock(m_cs);
		
        m_currentState.m_bInOperation = false;
        }

    // push the current state onto the recent snapshot set stack
    void PushCurrentState();

    // set the current state
    void SetCurrentState(IN VSS_WRITER_STATE state)
        {
		CVssSafeAutomaticLock lock(m_cs);
		
		CVssAutoDiagLogger	logger(*this, state, 
			GetCurrentSnapshotSet(),
			CVssDiag::VSS_DIAG_IGNORE_LEAVE
			   	| CVssDiag::VSS_DIAG_IS_STATE);
		
        m_currentState.m_state = state;
        }

    // get current state
    VSS_WRITER_STATE GetCurrentState()
        {
        return m_currentState.m_state;
        }

    // set current failure
    void SetCurrentFailure(IN HRESULT hrWriterFailure)
        {
		CVssSafeAutomaticLock lock(m_cs);

		// Make sure S_OK is translated
		CVssAutoDiagLogger	logger(*this, 
			hrWriterFailure? hrWriterFailure: VSS_S_OK, 
			GetCurrentSnapshotSet(),
			CVssDiag::VSS_DIAG_IGNORE_LEAVE 
				| CVssDiag::VSS_DIAG_IS_HRESULT);
		
        m_currentState.m_hrWriterFailure = hrWriterFailure;
        }

    // obtain the current failure
    HRESULT GetCurrentFailure()
        {
        return m_currentState.m_hrWriterFailure;
        }


    // obtain the snapshot set for the current state
    VSS_ID GetCurrentSnapshotSet()
    	{
    	return m_currentState.m_idSnapshotSet;
    	}
    
    // handle backup complete state transition to being stable
    void FinishBackupComplete(const VSS_ID &id);

    // indicate that backup complete failed
    void SetBackupCompleteStatus(const VSS_ID &id, HRESULT hr);


    // determine if a snapshot set id is in the cache of previous
    // snapshot sets
    bool CVssWriterState::IsSnapshotSetIdValid(VSS_ID &id)
        {
	    CVssSafeAutomaticLock lock(m_cs);
        INT nPrevious = SearchForPreviousSequence(id);

        return nPrevious != INVALID_SEQUENCE_INDEX;
        }

    // set a failure in the case where a writer is returning a
    // no response error.  It first checks to see if we are still
    // in the operation.  If not, then we need to retry obtaining
    // the writer's state
    bool SetNoResponseFailure(
    	IN const VSS_ID &id, 
    	IN const VSWRITER_STATE &state
    	);

	CVssDiag &	GetDiag() { return m_diag; };

private:
    // search for a previous state
    INT SearchForPreviousSequence(IN const VSS_ID& idSnapshotSet);

    // critical section protecting class
    CVssSafeCriticalSection m_cs;

    // current state
    VSWRITER_STATE m_currentState;

    // structures to keep track of writer status from previous snapshots
    enum
        {
        MAX_PREVIOUS_SNAPSHOTS = 8,
        INVALID_SEQUENCE_INDEX = -1
        };

    // previous states
    VSWRITER_STATE m_rgPreviousStates[MAX_PREVIOUS_SNAPSHOTS];

    // current slot for dumping a previous snapshots result
    volatile UINT m_iPreviousSnapshots;

    // are we currently in a sequence
    volatile bool m_bSequenceInProgress;

    CVssDiag &	  m_diag;
    };



/////////////////////////////////////////////////////////////////////////////
// CVssWriterImpl


class ATL_NO_VTABLE CVssWriterImpl :
    public CComObjectRootEx<CComMultiThreadModel>,
    public IVssWriterImpl
    {

public:
    friend class CVssWriterImplLock;

    // Constructors & Destructors
    CVssWriterImpl();

    ~CVssWriterImpl();

// Exposed operations
public:
    // create a writer implementation for a specific writer
    static void CreateWriter
        (
        CVssWriter *pWriter,
        IVssWriterImpl **ppImpl
        );

    // set external writer object
    void SetWriter(CVssWriter *pWriter)
        {
        BS_ASSERT(pWriter);
        m_pWriter = pWriter;
        }

    // initialize class
    void Initialize
        (
        IN VSS_ID WriterID,
        IN LPCWSTR wszWriterName,
        IN VSS_USAGE_TYPE ut,
        IN VSS_SOURCE_TYPE st,
        IN VSS_APPLICATION_LEVEL nLevel,
        IN DWORD dwTimeoutFreeze
        );

    // subscribe to writer events
    void Subscribe
        (
        );

    // unsubscribe from writer events
    void Unsubscribe();

    // uninitialize the writer
    void Uninitialize();

    // get array of volume names
    LPCWSTR* GetCurrentVolumeArray() const { return (LPCWSTR *) m_ppwszVolumesArray; };

    // get count of volumes in array
    UINT GetCurrentVolumeCount() const { return m_nVolumesCount; };

    // get the snapshot device name for a particular volume
    HRESULT GetSnapshotDeviceName
        (
        LPCWSTR wszOriginalVolume,
        LPCWSTR* ppwszSnapshotDevice
        ) const;

    // get id of snapshot
    VSS_ID GetCurrentSnapshotSetId() const { return m_CurrentSnapshotSetId; };

    // get the current backup context
    LONG GetContext() const { return m_lContext; }
	
    // get level at which freeze takes place
    VSS_APPLICATION_LEVEL GetCurrentLevel() const { return m_nLevel; };

    // determine if path is included in the snapshot
    bool IsPathAffected(IN  LPCWSTR wszPath) const;

    // determine if the backup is including bootable system state
    bool IsBootableSystemStateBackedUp() const
        { return m_bBootableSystemStateBackup ? true : false; }

    // determine if the backup selects components
    bool AreComponentsSelected() const
        { return m_bComponentsSelected ? true : false; }

    // return the type of backup
    VSS_BACKUP_TYPE GetBackupType() const { return m_backupType; }

    VSS_RESTORE_TYPE GetRestoreType() const { return m_restoreType; }

    // indicate why the writer failed
    HRESULT SetWriterFailure(HRESULT hr);

    // does requestor support partial file backups and restores
    bool IsPartialFileSupportEnabled() const
        {
        return m_bPartialFileSupport ? true : false;
        }

// IVssWriter ovverides
public:

BEGIN_COM_MAP(CVssWriterImpl)
    COM_INTERFACE_ENTRY(IVssWriter)
END_COM_MAP()

    // request WRITER_METADATA or writer state
    STDMETHOD(RequestWriterInfo)(
        IN      BSTR bstrSnapshotSetId,
        IN      BOOL bWriterMetadata,
        IN      BOOL bWriterState,
        IN      IDispatch* pWriterCallback
        );

    // prepare for backup event
    STDMETHOD(PrepareForBackup)(
        IN      BSTR bstrSnapshotSetId,
        IN      IDispatch* pWriterCallback
        );

    // prepare for snapshot event
    STDMETHOD(PrepareForSnapshot)(
        IN      BSTR bstrSnapshotSetId,
        IN      BSTR VolumeNamesList
        );

    // freeze event
    STDMETHOD(Freeze)(
        IN      BSTR bstrSnapshotSetId,
        IN      INT nApplicationLevel
        );

    // thaw event
    STDMETHOD(Thaw)(
        IN      BSTR bstrSnapshotSetId
        );

    STDMETHOD(PostSnapshot)(
        IN      BSTR bstrSnapshotSetId,
        IN      IDispatch *pWriterCallback,
        IN      BSTR SnapshotDevicesList
        );

    // backup complete event
    STDMETHOD(BackupComplete)(
        IN      BSTR bstrSnapshotSetId,
        IN      IDispatch* pWriterCallback
        );

    // backup shutdown event
    STDMETHOD(BackupShutdown)(
    	IN 	   BSTR bstrSnapshotSetId
    	);
	
    // abort event
    STDMETHOD(Abort)(
        IN      BSTR bstrSnapshotSetId
        );

    STDMETHOD(PreRestore)(
        IN      IDispatch* pWriterCallback
        );

    STDMETHOD(PostRestore)(
        IN      IDispatch* pWriterCallback
        );



// Implementation - methods
private:
    enum VSS_EVENT_MASK
        {
        VSS_EVENT_PREPAREBACKUP     = 0x00000001,
        VSS_EVENT_PREPARESNAPSHOT   = 0x00000002,
        VSS_EVENT_FREEZE            = 0x00000004,
        VSS_EVENT_THAW              = 0x00000008,
        VSS_EVENT_POST_SNAPSHOT     = 0x00000010,
        VSS_EVENT_ABORT             = 0x00000020,
        VSS_EVENT_BACKUPCOMPLETE    = 0x00000040,
        VSS_EVENT_REQUESTINFO       = 0x00000080,
        VSS_EVENT_PRERESTORE        = 0x00000100,
        VSS_EVENT_POSTRESTORE       = 0x00000200,        
        VSS_EVENT_BACKUPSHUTDOWN = 0x00000400,
        VSS_EVENT_ALL               = 0x7ff,
        };

    // get WRITER callback from IDispatch
    void GetCallback
        (
        IN IDispatch *pWriterCallback,
        OUT IVssWriterCallback **ppCallback,
        IN BOOL bAllowImpersonate = FALSE
        );

    // reset state machine
    void ResetSequence
        (
        IN bool bCalledFromTimerThread
        );

    // abort the current snapshot sequence
    void DoAbort
        (
        IN bool bCalledFromTimerThread,
        IN BSTR strSnapshotSetId = NULL
        );

    // obtain components for this writer
    void InternalGetWriterComponents
        (
        IN IVssWriterCallback *pCallback,
        OUT IVssWriterComponentsInt **ppWriter,
        IN bool bWriteable,
        IN bool bInRestore
        );

    void SaveChangedComponents
        (
        IN IVssWriterCallback *pCallback,
        IN bool bInRestore,
        IN IVssWriterComponentsInt *pComponents
        );

    // create WRITER_METADATA XML document
    CVssCreateWriterMetadata *CreateBasicWriterMetadata();

    // startup routine for timer thread
    static DWORD StartTimerThread(void *pv);

    // function to run in timer thread
    void TimerFunc(VSS_ID id);

    // enter a state
    bool EnterState
        (
        IN const CVssWriterImplStateMachine &vwsm,
        IN BSTR bstrSnapshotSetId
        ) throw(HRESULT);

    // leave a state
    void LeaveState
        (
        IN const CVssWriterImplStateMachine &vwsm,
        IN bool fSuccessful
        );

    // create a Handle to an event
    void SetupEvent
        (
        IN HANDLE *phevt
        ) throw(HRESULT);

    // begin a sequence to create a snapshot
    void BeginSequence
        (
        IN CVssID &SnapshotSetId
        ) throw(HRESULT);


    // terminate timer thread
    void TerminateTimerThread();

    // lock critical section
    inline void Lock()
        {
        m_cs.Lock();
        m_bLocked = true;
        }

    // unlock critical section
    inline void Unlock()
        {
        m_bLocked = false;
        m_cs.Unlock();
        }

    // assert that critical section is locked
    inline void AssertLocked()
        {
        BS_ASSERT(m_bLocked);
        }

// Implementation - members
private:
    enum VSS_TIMER_COMMAND
        {
        VSS_TC_UNDEFINED,
        VSS_TC_ABORT_CURRENT_SEQUENCE,
        VSS_TC_TERMINATE_THREAD,
        VSS_TIMEOUT_FREEZE = 120*1000,      // two minutes
        VSS_STACK_SIZE = 256 * 1024         // 256K
        };

    enum
        {
        x_MAX_SUBSCRIPTIONS = 32
        };



    // data related to writer

    // writer class id
    VSS_ID m_WriterID;

    // writer instance id
    VSS_ID m_InstanceID;

    // usage type for writer
    VSS_USAGE_TYPE m_usage;

    // data source type for writer
    VSS_SOURCE_TYPE m_source;

    // writer name
    LPWSTR m_wszWriterName;

    // Data related to the current sequence

    // snapshot set id
    VSS_ID m_CurrentSnapshotSetId;

    // context
    LONG m_lContext;
	
    // volume array list passed in as a string
    LPWSTR m_pwszLocalVolumeNameList;

    // # of volumes in volume array
    INT m_nVolumesCount;

    // volume array
    LPWSTR* m_ppwszVolumesArray;

    // Subscription-related data
    CComBSTR m_bstrSubscriptionName;

    // actual subscription ids
    CComBSTR m_rgbstrSubscriptionId[x_MAX_SUBSCRIPTIONS];

    // number of allocated subscription ids
    UINT m_cbstrSubscriptionId;

    // Data related with the Writer object

    // which freeze event is handled
    VSS_APPLICATION_LEVEL m_nLevel;

    // what events are subscribed to
    DWORD m_dwEventMask;

    // Critical section or avoiding race between tasks
    CVssSafeCriticalSection             m_cs;

    // was critical section initialized
    bool m_bLockCreated;

    // flag indicating if critical section is locked
    bool m_bLocked;

    // timeout and queuing mechanisms
    HANDLE m_hevtTimerThread;       // event used to signal timer thread if timer is aborted
    HANDLE m_hmtxTimerThread;       // mutex used to guarantee only one timer thread exists at a time
    HANDLE m_hThreadTimerThread;    // handle to timer thread
    VSS_TIMER_COMMAND m_command;    // timer command when it exits the wait
    DWORD m_dwTimeoutFreeze;        // timeout for freeze

    // actual writer implementation
    CVssWriter *m_pWriter;


    // state of backup components
    BOOL m_bBootableSystemStateBackup;
    BOOL m_bComponentsSelected;
    VSS_BACKUP_TYPE m_backupType;
    VSS_RESTORE_TYPE m_restoreType;
	
    BOOL m_bPartialFileSupport;


    // state of writer
    CVssWriterState m_writerstate;

    // TRUE if an OnPrepareForBackup/Freeze/Thaw
    // was sent and without a corresponding OnAbort
    bool m_bOnAbortPermitted;

    // is a sequence in progress
    bool m_bSequenceInProgress;

    // current state
    CVssSidCollection m_SidCollection;

	// Initialization flag
	bool m_bInitialized;

	// This flags are TRUE only during Setup/SafeMode 
	bool m_bInSafeMode;
	bool m_bInSetup;

	// Diagnose tool
	CVssDiag	m_diag;
    };


// auto class for locks
class CVssWriterImplLock
    {
public:
    CVssWriterImplLock(CVssWriterImpl *pImpl) :
        m_pImpl(pImpl)
        {
        m_pImpl->Lock();
        }

    ~CVssWriterImplLock()
        {
        m_pImpl->Unlock();
        }

private:
    CVssWriterImpl *m_pImpl;
    };







#endif //__CVSS_WRITER_IMPL_H_