/*++

Copyright (c) 2005 - 2009, Intel Corporation
All rights reserved. This program and the accompanying materials are licensed and made available
under the terms and conditions of the BSD License which accompanies this
distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php

THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.


Module Name:

  ReadWrite.c

Abstract:

  Functions that perform file read/write

Revision History

--*/

#include "Fat.h"

EFI_STATUS
EFIAPI
FatGetPosition (
  IN  EFI_FILE_PROTOCOL *FHand,
  OUT UINT64            *Position
  )
/*++

Routine Description:

  Get the file's position of the file.

Arguments:

  FHand                 - The handle of file.
  Position              - The file's position of the file.

Returns:

  EFI_SUCCESS           - Get the info successfully.
  EFI_DEVICE_ERROR      - Can not find the OFile for the file.
  EFI_UNSUPPORTED       - The open file is not a file.

--*/
{
  FAT_IFILE *IFile;
  FAT_OFILE *OFile;

  IFile = IFILE_FROM_FHAND (FHand);
  OFile = IFile->OFile;

  if (OFile->Error == EFI_NOT_FOUND) {
    return EFI_DEVICE_ERROR;
  }

  if (OFile->ODir != NULL) {
    return EFI_UNSUPPORTED;
  }

  *Position = IFile->Position;
  return EFI_SUCCESS;
}

EFI_STATUS
EFIAPI
FatSetPosition (
  IN EFI_FILE_PROTOCOL  *FHand,
  IN UINT64             Position
  )
/*++

Routine Description:

  Set the file's position of the file.

Arguments:

  FHand                 - The handle of file.
  Position              - The file's position of the file.

Returns:

  EFI_SUCCESS           - Set the info successfully.
  EFI_DEVICE_ERROR      - Can not find the OFile for the file.
  EFI_UNSUPPORTED       - Set a directory with a not-zero position.

--*/
{
  FAT_IFILE *IFile;
  FAT_OFILE *OFile;

  IFile = IFILE_FROM_FHAND (FHand);
  OFile = IFile->OFile;

  if (OFile->Error == EFI_NOT_FOUND) {
    return EFI_DEVICE_ERROR;
  }
  //
  // If this is a directory, we can only set back to position 0
  //
  if (OFile->ODir != NULL) {
    if (Position != 0) {
      //
      // Reset current directory cursor;
      //
      return EFI_UNSUPPORTED;
    }

    FatResetODirCursor (OFile);
  }
  //
  // Set the position
  //
  if (Position == -1) {
    Position = OFile->FileSize;
  }
  //
  // Set the position
  //
  IFile->Position = Position;
  return EFI_SUCCESS;
}

EFI_STATUS
FatIFileReadDir (
  IN     FAT_IFILE              *IFile,
  IN OUT UINTN                  *BufferSize,
     OUT VOID                   *Buffer
  )
/*++

Routine Description:

  Get the file info from the open file of the IFile into Buffer.

Arguments:

  IFile                 - The instance of the open file.
  BufferSize            - Size of Buffer.
  Buffer                - Buffer containing read data.

Returns:

  EFI_SUCCESS           - Get the file info successfully.
  other                 - An error occurred when operation the disk.

--*/
{
  EFI_STATUS  Status;
  FAT_OFILE   *OFile;
  FAT_ODIR    *ODir;
  FAT_DIRENT  *DirEnt;
  UINT32      CurrentPos;

  OFile       = IFile->OFile;
  ODir        = OFile->ODir;
  CurrentPos  = ((UINT32) IFile->Position) / sizeof (FAT_DIRECTORY_ENTRY);

  //
  // We need to relocate the directory
  //
  if (CurrentPos < ODir->CurrentPos) {
    //
    // The directory cursor has been modified by another IFile, we reset the cursor
    //
    FatResetODirCursor (OFile);
  }
  //
  // We seek the next directory entry's position
  //
  do {
    Status = FatGetNextDirEnt (OFile, &DirEnt);
    if (EFI_ERROR (Status) || DirEnt == NULL) {
      //
      // Something error occurred or reach the end of directory,
      // return 0 buffersize
      //
      *BufferSize = 0;
      goto Done;
    }
  } while (ODir->CurrentPos <= CurrentPos);
  Status = FatGetDirEntInfo (OFile->Volume, DirEnt, BufferSize, Buffer);

Done:
  //
  // Update IFile's Position
  //
  if (!EFI_ERROR (Status)) {
    //
    // Update IFile->Position, if everything is all right
    //
    CurrentPos      = ODir->CurrentPos;
    IFile->Position = (UINT64) (CurrentPos * sizeof (FAT_DIRECTORY_ENTRY));
  }

  return Status;
}

EFI_STATUS
FatIFileAccess (
  IN     EFI_FILE_PROTOCOL     *FHand,
  IN     IO_MODE               IoMode,
  IN OUT UINTN                 *BufferSize,
  IN OUT VOID                  *Buffer
  )
/*++

Routine Description:

  Get the file info from the open file of the IFile into Buffer.

Arguments:

  FHand                 - The file handle to access.
  IoMode                - Indicate whether the access mode is reading or writing.
  BufferSize            - Size of Buffer.
  Buffer                - Buffer containing read data.

Returns:

  EFI_SUCCESS           - Get the file info successfully.
  EFI_DEVICE_ERROR      - Can not find the OFile for the file.
  EFI_VOLUME_CORRUPTED  - The file type of open file is error.
  EFI_WRITE_PROTECTED   - The disk is write protect.
  EFI_ACCESS_DENIED     - The file is read-only.
  other                 - An error occurred when operating on the disk.

--*/
{
  EFI_STATUS  Status;
  FAT_IFILE   *IFile;
  FAT_OFILE   *OFile;
  FAT_VOLUME  *Volume;
  UINT64      EndPosition;

  IFile  = IFILE_FROM_FHAND (FHand);
  OFile  = IFile->OFile;
  Volume = OFile->Volume;

  if (OFile->Error == EFI_NOT_FOUND) {
    return EFI_DEVICE_ERROR;
  }

  if (IoMode == READ_DATA) {
    //
    // If position is at EOF, then return device error
    //
    if (IFile->Position > OFile->FileSize) {
      return EFI_DEVICE_ERROR;
    }
  } else {
    //
    // Check if the we can write data
    //
    if (Volume->ReadOnly) {
      return EFI_WRITE_PROTECTED;
    }

    if (IFile->ReadOnly) {
      return EFI_ACCESS_DENIED;
    }
  }

  FatAcquireLock ();

  Status = OFile->Error;
  if (!EFI_ERROR (Status)) {
    if (OFile->ODir != NULL) {
      //
      // Access a directory
      //
      Status = EFI_UNSUPPORTED;
      if (IoMode == READ_DATA) {
        //
        // Read a directory is supported
        //
        Status = FatIFileReadDir (IFile, BufferSize, Buffer);
      }

      OFile = NULL;
    } else {
      //
      // Access a file
      //
      EndPosition = IFile->Position + *BufferSize;
      if (EndPosition > OFile->FileSize) {
        //
        // The position goes beyond the end of file
        //
        if (IoMode == READ_DATA) {
          //
          // Adjust the actual size read
          //
          *BufferSize -= (UINTN) EndPosition - OFile->FileSize;
        } else {
          //
          // We expand the file size of OFile
          //
          Status = FatGrowEof (OFile, EndPosition);
          if (EFI_ERROR (Status)) {
            //
            // Must update the file's info into the file's Directory Entry
            // and then flush the dirty cache info into disk.
            //
            *BufferSize = 0;
            FatOFileFlush (OFile);
            OFile = NULL;
            goto Done;
          }

          FatUpdateDirEntClusterSizeInfo (OFile);
        }
      }

      Status = FatAccessOFile (OFile, IoMode, (UINTN) IFile->Position, BufferSize, Buffer);
      IFile->Position += *BufferSize;
    }
  }

Done:
  if (EFI_ERROR (Status)) {
    Status = FatCleanupVolume (Volume, OFile, Status);
  }
  //
  // On EFI_SUCCESS case, not calling FatCleanupVolume():
  // 1) The Cache flush operation is avoided to enhance
  // performance. Caller is responsible to call Flush() when necessary.
  // 2) The volume dirty bit is probably set already, and is expected to be
  // cleaned in subsequent Flush() or other operations.
  // 3) Write operation doesn't affect OFile/IFile structure, so
  // Reference checking is not necessary.
  //
  FatReleaseLock ();
  return Status;
}

EFI_STATUS
EFIAPI
FatRead (
  IN     EFI_FILE_PROTOCOL  *FHand,
  IN OUT UINTN              *BufferSize,
     OUT VOID               *Buffer
  )
/*++

Routine Description:

  Get the file info.

Arguments:

  FHand                 - The handle of the file.
  BufferSize            - Size of Buffer.
  Buffer                - Buffer containing read data.

Returns:

  EFI_SUCCESS           - Get the file info successfully.
  EFI_DEVICE_ERROR      - Can not find the OFile for the file.
  EFI_VOLUME_CORRUPTED  - The file type of open file is error.
  other                 - An error occurred when operation the disk.

--*/
{
  return FatIFileAccess (FHand, READ_DATA, BufferSize, Buffer);
}

EFI_STATUS
EFIAPI
FatWrite (
  IN     EFI_FILE_PROTOCOL  *FHand,
  IN OUT UINTN              *BufferSize,
  IN     VOID               *Buffer
  )
/*++

Routine Description:

  Write the content of buffer into files.

Arguments:

  FHand                 - The handle of the file.
  BufferSize            - Size of Buffer.
  Buffer                - Buffer containing write data.

Returns:

  EFI_SUCCESS           - Set the file info successfully.
  EFI_WRITE_PROTECTED   - The disk is write protect.
  EFI_ACCESS_DENIED     - The file is read-only.
  EFI_DEVICE_ERROR      - The OFile is not valid.
  EFI_UNSUPPORTED       - The open file is not a file.
                        - The writing file size is larger than 4GB.
  other                 - An error occurred when operation the disk.

--*/
{
  return FatIFileAccess (FHand, WRITE_DATA, BufferSize, Buffer);
}

EFI_STATUS
FatAccessOFile (
  IN     FAT_OFILE      *OFile,
  IN     IO_MODE        IoMode,
  IN     UINTN          Position,
  IN OUT UINTN          *DataBufferSize,
  IN OUT UINT8          *UserBuffer
  )
/*++

Routine Description:

  This function reads data from a file or writes data to a file.
  It uses OFile->PosRem to determine how much data can be accessed in one time.

Arguments:

  OFile                 - The open file.
  IoMode                - Indicate whether the access mode is reading or writing.
  Position              - The position where data will be accessed.
  DataBufferSize        - Size of Buffer.
  UserBuffer            - Buffer containing data.

Returns:

  EFI_SUCCESS           - Access the data successfully.
  other                 - An error occurred when operating on the disk.

--*/
{
  FAT_VOLUME  *Volume;
  UINTN       Len;
  EFI_STATUS  Status;
  UINTN       BufferSize;

  BufferSize  = *DataBufferSize;
  Volume      = OFile->Volume;
  ASSERT_VOLUME_LOCKED (Volume);

  Status = EFI_SUCCESS;
  while (BufferSize > 0) {
    //
    // Seek the OFile to the file position
    //
    Status = FatOFilePosition (OFile, Position, BufferSize);
    if (EFI_ERROR (Status)) {
      break;
    }
    //
    // Clip length to block run
    //
    Len = BufferSize > OFile->PosRem ? OFile->PosRem : BufferSize;

    //
    // Write the data
    //
    Status = FatDiskIo (Volume, IoMode, OFile->PosDisk, Len, UserBuffer);
    if (EFI_ERROR (Status)) {
      break;
    }
    //
    // Data was successfully accessed
    //
    Position   += Len;
    UserBuffer += Len;
    BufferSize -= Len;
    if (IoMode == WRITE_DATA) {
      OFile->Dirty    = TRUE;
      OFile->Archive  = TRUE;
    }
    //
    // Make sure no outbound occurred
    //
    ASSERT (Position <= OFile->FileSize);
  }
  //
  // Update the number of bytes accessed
  //
  *DataBufferSize -= BufferSize;
  return Status;
}

EFI_STATUS
FatExpandOFile (
  IN FAT_OFILE          *OFile,
  IN UINT64             ExpandedSize
  )
/*++

Routine Description:

  Expand OFile by appending zero bytes at the end of OFile.

Arguments:

  OFile                 - The open file.
  ExpandedSize          - The number of zero bytes appended at the end of the file.

Returns:

  EFI_SUCCESS           - The file is expanded successfully.
  other                 - An error occurred when expanding file.

--*/
{
  EFI_STATUS  Status;
  UINTN       WritePos;

  WritePos  = OFile->FileSize;
  Status    = FatGrowEof (OFile, ExpandedSize);
  if (!EFI_ERROR (Status)) {
    Status = FatWriteZeroPool (OFile, WritePos);
  }

  return Status;
}

EFI_STATUS
FatWriteZeroPool (
  IN FAT_OFILE  *OFile,
  IN UINTN      WritePos
  )
/*++

Routine Description:

  Write zero pool from the WritePos to the end of OFile.

Arguments:

  OFile                 - The open file to write zero pool.
  WritePos              - The number of zero bytes written.

Returns:

  EFI_SUCCESS           - Write the zero pool successfully.
  EFI_OUT_OF_RESOURCES  - Not enough memory to perform the operation.
  other                 - An error occurred when writing disk.

--*/
{
  EFI_STATUS  Status;
  VOID        *ZeroBuffer;
  UINTN       AppendedSize;
  UINTN       BufferSize;
  UINTN       WriteSize;

  AppendedSize  = OFile->FileSize - WritePos;
  BufferSize    = AppendedSize;
  if (AppendedSize > FAT_MAX_ALLOCATE_SIZE) {
    //
    // If the appended size is larger, maybe we can not allocate the whole
    // memory once. So if the growed size is larger than 10M, we just
    // allocate 10M memory (one healthy system should have 10M available
    // memory), and then write the zerobuffer to the file several times.
    //
    BufferSize = FAT_MAX_ALLOCATE_SIZE;
  }

  ZeroBuffer = AllocateZeroPool (BufferSize);
  if (ZeroBuffer == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  do {
    WriteSize     = AppendedSize > BufferSize ? BufferSize : (UINTN) AppendedSize;
    AppendedSize -= WriteSize;
    Status = FatAccessOFile (OFile, WRITE_DATA, WritePos, &WriteSize, ZeroBuffer);
    if (EFI_ERROR (Status)) {
      break;
    }

    WritePos += WriteSize;
  } while (AppendedSize > 0);

  FreePool (ZeroBuffer);
  return Status;
}

EFI_STATUS
FatTruncateOFile (
  IN FAT_OFILE          *OFile,
  IN UINTN              TruncatedSize
  )
/*++

Routine Description:

  Truncate the OFile to smaller file size.

Arguments:

  OFile                 - The open file.
  TruncatedSize         - The new file size.

Returns:

  EFI_SUCCESS           - The file is truncated successfully.
  other                 - An error occurred when truncating file.

--*/
{
  OFile->FileSize = TruncatedSize;
  return FatShrinkEof (OFile);
}