/*

 * Copyright (c) 2020 Red Hat, Inc.

 *

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

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2

 * of the License, or (at your option) any later version.

 * 

 * 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, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

 * 02110-1301, USA. 

 *

 * $Id: //eng/uds-releases/jasper/src/uds/indexState.h#5 $

 */

#ifndef INDEX_STATE_H

#define INDEX_STATE_H 1

#include "buffer.h"

#include "indexComponent.h"

/**

 * Used here and in SingleFileLayout.

 **/

typedef enum {

  IS_SAVE,

  IS_CHECKPOINT,

  NO_SAVE = 9999,

} IndexSaveType;

/*

 * Used in getStateIndexStateBuffer to identify whether the index state buffer

 * is for the index being loaded or the index being saved.

 */

typedef enum {

  IO_READ  = 0x1,

  IO_WRITE = 0x2,

} IOAccessMode;

/**

 * The index state structure controls the loading and saving of the index

 * state.

 **/

typedef struct indexState {

  struct indexLayout *layout;

  unsigned int        zoneCount;  // number of index zones to use

  unsigned int        loadZones;

  unsigned int        loadSlot;

  unsigned int        saveSlot;

  unsigned int        count;     // count of registered entries (<= length)

  unsigned int        length;    // total span of array allocation

  bool                saving;    // incremental save in progress

  IndexComponent     *entries[]; // array of index component entries

} IndexState;

/**

 * Make an index state object,

 *

 * @param [in]  layout         The index layout.

 * @param [in]  numZones       The number of zones to use.

 * @param [in]  maxComponents  The maximum number of components to be handled.

 * @param [out] statePtr       Where to store the index state object.

 *

 * @return UDS_SUCCESS or an error code

 **/

int makeIndexState(struct indexLayout  *layout,

                   unsigned int         numZones,

                   unsigned int         maxComponents,

                   IndexState         **statePtr)

  __attribute__((warn_unused_result));

/**

 * Free an index state (generically).

 *

 * @param statePtr      The pointer to the index state to be freed and

 *                      set to NULL.

 **/

void freeIndexState(IndexState **statePtr);

/**

 * Add an index component to an index state.

 *

 * @param state     The index directory in which to add this component.

 * @param info      The index component file specification.

 * @param data      The per-component data structure.

 * @param context   The load/save context of the component.

 *

 * @return          UDS_SUCCESS or an error code.

 **/

int addIndexStateComponent(IndexState               *state,

                           const IndexComponentInfo *info,

                           void                     *data,

                           void                     *context)

  __attribute__((warn_unused_result));

/**

 * Load index state

 *

 * @param state      The index state.

 * @param replayPtr  If set, the place to hold whether a replay is required.

 *

 * @return           UDS_SUCCESS or error

 **/

int loadIndexState(IndexState *state, bool *replayPtr)

  __attribute__((warn_unused_result));

/**

 * Save the current index state, including the open chapter.

 *

 * @param state         The index state.

 *

 * @return              UDS_SUCCESS or error

 **/

int saveIndexState(IndexState *state) __attribute__((warn_unused_result));

/**

 *  Prepare to save the index state.

 *

 *  @param state     the index state

 *  @param saveType  whether a checkpoint or save

 *

 *  @return UDS_SUCCESS or an error code

 **/

int prepareToSaveIndexState(IndexState *state, IndexSaveType saveType)

  __attribute__((warn_unused_result));

/**

 * Write index checkpoint non-incrementally (for testing).

 *

 * @param state         The index state.

 *

 * @return              UDS_SUCCESS or error

 **/

int writeIndexStateCheckpoint(IndexState *state)

  __attribute__((warn_unused_result));

/**

 * Sets up an index state checkpoint which will proceed incrementally.

 * May create the directory but does not actually write any data.

 *

 * @param state         The index state.

 *

 * @return              UDS_SUCCESS or an error code.

 **/

int startIndexStateCheckpoint(IndexState *state)

  __attribute__((warn_unused_result));

/**

 * Perform operations on index state checkpoints that are synchronized to

 * the chapter writer thread.

 *

 * @param state         The index state.

 *

 * @return              UDS_SUCCESS or an error code.

 **/

int performIndexStateCheckpointChapterSynchronizedSaves(IndexState *state)

  __attribute__((warn_unused_result));

/**

 * Performs zone-specific (and, for zone 0, general) incremental checkpointing.

 *

 * @param [in]  state           The index state.

 * @param [in]  zone            The zone number.

 * @param [out] completed       Set to whether the checkpoint has completed

 *                              for this zone.

 *

 * @return              UDS_SUCCESS or an error code.

 **/

int performIndexStateCheckpointInZone(IndexState       *state,

                                      unsigned int      zone,

                                      CompletionStatus *completed)

  __attribute__((warn_unused_result));

/**

 * Force the completion of an incremental index state checkpoint

 * for a particular zone.

 *

 * @param [in] state    The index state.

 * @param [in]  zone            The zone number.

 * @param [out] completed       Set to whether the checkpoint has completed

 *                              for this zone.

 *

 * @return              UDS_SUCCESS or an error code.

 **/

int finishIndexStateCheckpointInZone(IndexState       *state,

                                     unsigned int      zone,

                                     CompletionStatus *completed)

  __attribute__((warn_unused_result));

/**

 * Force the completion of an incremental index state checkpoint once

 * all zones are completed.

 *

 * @param [in] state    The index state.

 *

 * @return              UDS_SUCCESS or an error code.

 **/

int finishIndexStateCheckpoint(IndexState *state)

  __attribute__((warn_unused_result));

/**

 * Aborts an index state checkpoint which is proceeding incrementally

 * for a particular zone.

 *

 * @param [in]  state           The index state.

 * @param [in]  zone            The zone number.

 * @param [out] completed       Set to whether the checkpoint has completed or

 *                              aborted for this zone.

 *

 * @return              UDS_SUCCESS or an error code.

 **/

int abortIndexStateCheckpointInZone(IndexState       *state,

                                    unsigned int      zone,

                                    CompletionStatus *completed);

/**

 * Aborts an index state checkpoint which is proceeding incrementally,

 * once all the zones are aborted.

 *

 * @param [in]  state   The index state.

 *

 * @return              UDS_SUCCESS or an error code.

 **/

int abortIndexStateCheckpoint(IndexState *state);

/**

 * Remove or disable the index state data, for testing.

 *

 * @param state         The index state

 *

 * @return UDS_SUCCESS or an error code

 *

 * @note the return value of this function is frequently ignored

 **/

int discardIndexStateData(IndexState *state);

/**

 * Discard the last index state save, for testing.

 *

 * @param state         The index state

 *

 * @return UDS_SUCCESS or an error code

 *

 * @note the return value of this function is frequently ignored

 **/

int discardLastIndexStateSave(IndexState *state);

/**

 * Find index component, for testing.

 *

 * @param state The index state

 * @param info  The index component file specification

 *

 * @return      The index component, or NULL if not found

 **/

IndexComponent *findIndexComponent(const IndexState         *state,

                                   const IndexComponentInfo *info)

  __attribute__((warn_unused_result));

/**

 * Get the indexStateBuffer for a specified mode.

 *

 * @param state      The index state.

 * @param mode       One of IO_READ or IO_WRITE.

 *

 * @return the index state buffer

 **/

Buffer *getStateIndexStateBuffer(IndexState *state, IOAccessMode mode)

  __attribute__((warn_unused_result));

/**

 * Open a BufferedReader for a specified state, kind, and zone.

 * This helper function is used by IndexComponent.

 *

 * @param state      The index state.

 * @param kind       The kind if index save region to open.

 * @param zone       The zone number for the region.

 * @param readerPtr  Where to store the BufferedReader.

 *

 * @return UDS_SUCCESS or an error code.

 **/

int openStateBufferedReader(IndexState      *state,

                            RegionKind       kind,

                            unsigned int     zone,

                            BufferedReader **readerPtr)

  __attribute__((warn_unused_result));

/**

 * Open a BufferedWriter for a specified state, kind, and zone.

 * This helper function is used by IndexComponent.

 *

 * @param state      The index state.

 * @param kind       The kind if index save region to open.

 * @param zone       The zone number for the region.

 * @param writerPtr  Where to store the BufferedWriter.

 *

 * @return UDS_SUCCESS or an error code.

 **/

int openStateBufferedWriter(IndexState      *state,

                            RegionKind       kind,

                            unsigned int     zone,

                            BufferedWriter **writerPtr)

  __attribute__((warn_unused_result));

#endif // INDEX_STATE_H