diff options
Diffstat (limited to 'lib/backupclient/BackupStoreFileCombine.cpp')
| -rwxr-xr-x | lib/backupclient/BackupStoreFileCombine.cpp | 410 |
1 files changed, 410 insertions, 0 deletions
diff --git a/lib/backupclient/BackupStoreFileCombine.cpp b/lib/backupclient/BackupStoreFileCombine.cpp new file mode 100755 index 00000000..562a32d9 --- /dev/null +++ b/lib/backupclient/BackupStoreFileCombine.cpp @@ -0,0 +1,410 @@ +// -------------------------------------------------------------------------- +// +// File +// Name: BackupStoreFileCombine.cpp +// Purpose: File combining for BackupStoreFile +// Created: 16/1/04 +// +// -------------------------------------------------------------------------- + +#include "Box.h" + +#include <new> + +#include "BackupStoreFile.h" +#include "BackupStoreFileWire.h" +#include "BackupStoreObjectMagic.h" +#include "BackupStoreException.h" +#include "BackupStoreConstants.h" +#include "BackupStoreFilename.h" +#include "FileStream.h" + +#include "MemLeakFindOn.h" + +typedef struct +{ + int64_t mFilePosition; +} FromIndexEntry; + +static void LoadFromIndex(IOStream &rFrom, FromIndexEntry *pIndex, int64_t NumEntries); +static void CopyData(IOStream &rDiffData, IOStream &rDiffIndex, int64_t DiffNumBlocks, IOStream &rFrom, FromIndexEntry *pFromIndex, int64_t FromNumBlocks, IOStream &rOut); +static void WriteNewIndex(IOStream &rDiff, int64_t DiffNumBlocks, FromIndexEntry *pFromIndex, int64_t FromNumBlocks, IOStream &rOut); + +// -------------------------------------------------------------------------- +// +// Function +// Name: BackupStoreFile::CombineFile(IOStream &, IOStream &, IOStream &) +// Purpose: Where rDiff is a store file which is incomplete as a result of a +// diffing operation, rFrom is the file it is diffed from, and +// rOut is the stream in which to place the result, the old file +// and new file are combined into a file containing all the data. +// rDiff2 is the same file as rDiff, opened again to get two +// independent streams to the same file. +// Created: 16/1/04 +// +// -------------------------------------------------------------------------- +void BackupStoreFile::CombineFile(IOStream &rDiff, IOStream &rDiff2, IOStream &rFrom, IOStream &rOut) +{ + // Read and copy the header. + file_StreamFormat hdr; + if(!rDiff.ReadFullBuffer(&hdr, sizeof(hdr), 0)) + { + THROW_EXCEPTION(BackupStoreException, FailedToReadBlockOnCombine) + } + if(ntohl(hdr.mMagicValue) != OBJECTMAGIC_FILE_MAGIC_VALUE_V1) + { + THROW_EXCEPTION(BackupStoreException, BadBackupStoreFile) + } + // Copy + rOut.Write(&hdr, sizeof(hdr)); + // Copy over filename and attributes + // BLOCK + { + BackupStoreFilename filename; + filename.ReadFromStream(rDiff, IOStream::TimeOutInfinite); + filename.WriteToStream(rOut); + StreamableMemBlock attr; + attr.ReadFromStream(rDiff, IOStream::TimeOutInfinite); + attr.WriteToStream(rOut); + } + + // Read the header for the From file + file_StreamFormat fromHdr; + if(!rFrom.ReadFullBuffer(&fromHdr, sizeof(fromHdr), 0)) + { + THROW_EXCEPTION(BackupStoreException, FailedToReadBlockOnCombine) + } + if(ntohl(fromHdr.mMagicValue) != OBJECTMAGIC_FILE_MAGIC_VALUE_V1) + { + THROW_EXCEPTION(BackupStoreException, BadBackupStoreFile) + } + // Skip over the filename and attributes of the From file + // BLOCK + { + BackupStoreFilename filename2; + filename2.ReadFromStream(rFrom, IOStream::TimeOutInfinite); + int32_t size_s; + if(!rFrom.ReadFullBuffer(&size_s, sizeof(size_s), 0 /* not interested in bytes read if this fails */)) + { + THROW_EXCEPTION(CommonException, StreamableMemBlockIncompleteRead) + } + int size = ntohl(size_s); + // Skip forward the size + rFrom.Seek(size, IOStream::SeekType_Relative); + } + + // Allocate memory for the block index of the From file + int64_t fromNumBlocks = ntoh64(fromHdr.mNumBlocks); + // NOTE: An extra entry is required so that the length of the last block can be calculated + FromIndexEntry *pFromIndex = (FromIndexEntry*)::malloc((fromNumBlocks+1) * sizeof(FromIndexEntry)); + if(pFromIndex == 0) + { + throw std::bad_alloc(); + } + + try + { + // Load the index from the From file, calculating the offsets in the + // file as we go along, and enforce that everything should be present. + LoadFromIndex(rFrom, pFromIndex, fromNumBlocks); + + // Read in the block index of the Diff file in small chunks, and output data + // for each block, either from this file, or the other file. + int64_t diffNumBlocks = ntoh64(hdr.mNumBlocks); + CopyData(rDiff /* positioned at start of data */, rDiff2, diffNumBlocks, rFrom, pFromIndex, fromNumBlocks, rOut); + + // Read in the block index again, and output the new block index, simply + // filling in the sizes of blocks from the old file. + WriteNewIndex(rDiff, diffNumBlocks, pFromIndex, fromNumBlocks, rOut); + + // Free buffers + ::free(pFromIndex); + pFromIndex = 0; + } + catch(...) + { + // Clean up + if(pFromIndex != 0) + { + ::free(pFromIndex); + pFromIndex = 0; + } + throw; + } +} + + +// -------------------------------------------------------------------------- +// +// Function +// Name: static LoadFromIndex(IOStream &, FromIndexEntry *, int64_t) +// Purpose: Static. Load the index from the From file +// Created: 16/1/04 +// +// -------------------------------------------------------------------------- +static void LoadFromIndex(IOStream &rFrom, FromIndexEntry *pIndex, int64_t NumEntries) +{ + ASSERT(pIndex != 0); + ASSERT(NumEntries >= 0); + + // Get the starting point in the file + int64_t filePos = rFrom.GetPosition(); + + // Jump to the end of the file to read the index + rFrom.Seek(0 - ((NumEntries * sizeof(file_BlockIndexEntry)) + sizeof(file_BlockIndexHeader)), IOStream::SeekType_End); + + // Read block index header + file_BlockIndexHeader blkhdr; + if(!rFrom.ReadFullBuffer(&blkhdr, sizeof(blkhdr), 0)) + { + THROW_EXCEPTION(BackupStoreException, FailedToReadBlockOnCombine) + } + if(ntohl(blkhdr.mMagicValue) != OBJECTMAGIC_FILE_BLOCKS_MAGIC_VALUE_V1 + || (int64_t)ntoh64(blkhdr.mNumBlocks) != NumEntries) + { + THROW_EXCEPTION(BackupStoreException, BadBackupStoreFile) + } + + // And then the block entries + for(int64_t b = 0; b < NumEntries; ++b) + { + // Read + file_BlockIndexEntry en; + if(!rFrom.ReadFullBuffer(&en, sizeof(en), 0)) + { + THROW_EXCEPTION(BackupStoreException, FailedToReadBlockOnCombine) + } + + // Add to list + pIndex[b].mFilePosition = filePos; + + // Encoded size? + int64_t encodedSize = ntoh64(en.mEncodedSize); + // Check that the block is actually there + if(encodedSize <= 0) + { + THROW_EXCEPTION(BackupStoreException, OnCombineFromFileIsIncomplete) + } + + // Move file pointer on + filePos += encodedSize; + } + + // Store the position in the very last entry, so the size of the last entry can be calculated + pIndex[NumEntries].mFilePosition = filePos; +} + + +// -------------------------------------------------------------------------- +// +// Function +// Name: static CopyData(IOStream &, IOStream &, int64_t, IOStream &, FromIndexEntry *, int64_t, IOStream &) +// Purpose: Static. Copy data from the Diff and From file to the out file. +// rDiffData is at beginning of data. +// rDiffIndex at any position. +// rFrom is at any position. +// rOut is after the header, ready for data +// Created: 16/1/04 +// +// -------------------------------------------------------------------------- +static void CopyData(IOStream &rDiffData, IOStream &rDiffIndex, int64_t DiffNumBlocks, + IOStream &rFrom, FromIndexEntry *pFromIndex, int64_t FromNumBlocks, IOStream &rOut) +{ + // Jump to the end of the diff file to read the index + rDiffIndex.Seek(0 - ((DiffNumBlocks * sizeof(file_BlockIndexEntry)) + sizeof(file_BlockIndexHeader)), IOStream::SeekType_End); + + // Read block index header + file_BlockIndexHeader diffBlkhdr; + if(!rDiffIndex.ReadFullBuffer(&diffBlkhdr, sizeof(diffBlkhdr), 0)) + { + THROW_EXCEPTION(BackupStoreException, FailedToReadBlockOnCombine) + } + if(ntohl(diffBlkhdr.mMagicValue) != OBJECTMAGIC_FILE_BLOCKS_MAGIC_VALUE_V1 + || (int64_t)ntoh64(diffBlkhdr.mNumBlocks) != DiffNumBlocks) + { + THROW_EXCEPTION(BackupStoreException, BadBackupStoreFile) + } + + // Record where the From file is + int64_t fromPos = rFrom.GetPosition(); + + // Buffer data + void *buffer = 0; + int bufferSize = 0; + + try + { + // Read the blocks in! + for(int64_t b = 0; b < DiffNumBlocks; ++b) + { + // Read + file_BlockIndexEntry en; + if(!rDiffIndex.ReadFullBuffer(&en, sizeof(en), 0)) + { + THROW_EXCEPTION(BackupStoreException, FailedToReadBlockOnCombine) + } + + // What's the size value stored in the entry + int64_t encodedSize = ntoh64(en.mEncodedSize); + + // How much data will be read? + int32_t blockSize = 0; + if(encodedSize > 0) + { + // The block is actually in the diff file + blockSize = encodedSize; + } + else + { + // It's in the from file. First, check to see if it's valid + int64_t blockIdx = (0 - encodedSize); + if(blockIdx > FromNumBlocks) + { + // References a block which doesn't actually exist + THROW_EXCEPTION(BackupStoreException, BadBackupStoreFile) + } + // Calculate size. This operation is safe because of the extra entry at the end + blockSize = pFromIndex[blockIdx + 1].mFilePosition - pFromIndex[blockIdx].mFilePosition; + } + ASSERT(blockSize > 0); + + // Make sure there's memory available to copy this + if(bufferSize < blockSize || buffer == 0) + { + // Free old block + if(buffer != 0) + { + ::free(buffer); + buffer = 0; + bufferSize = 0; + } + // Allocate new block + buffer = ::malloc(blockSize); + if(buffer == 0) + { + throw std::bad_alloc(); + } + bufferSize = blockSize; + } + ASSERT(bufferSize >= blockSize); + + // Load in data from one of the files + if(encodedSize > 0) + { + // Load from diff file + if(!rDiffData.ReadFullBuffer(buffer, blockSize, 0)) + { + THROW_EXCEPTION(BackupStoreException, FailedToReadBlockOnCombine) + } + } + else + { + // Locate and read the data from the from file + int64_t blockIdx = (0 - encodedSize); + // Seek if necessary + if(fromPos != pFromIndex[blockIdx].mFilePosition) + { + rFrom.Seek(pFromIndex[blockIdx].mFilePosition, IOStream::SeekType_Absolute); + fromPos = pFromIndex[blockIdx].mFilePosition; + } + // Read + if(!rFrom.ReadFullBuffer(buffer, blockSize, 0)) + { + THROW_EXCEPTION(BackupStoreException, FailedToReadBlockOnCombine) + } + + // Update fromPos to current position + fromPos += blockSize; + } + + // Write data to out file + rOut.Write(buffer, blockSize); + } + + // Free buffer, if allocated + if(buffer != 0) + { + ::free(buffer); + buffer = 0; + } + } + catch(...) + { + if(buffer != 0) + { + ::free(buffer); + buffer = 0; + } + throw; + } +} + + + +// -------------------------------------------------------------------------- +// +// Function +// Name: static WriteNewIndex(IOStream &, int64_t, FromIndexEntry *, int64_t, IOStream &) +// Purpose: Write the index to the out file, just copying from the diff file and +// adjusting the entries. +// Created: 16/1/04 +// +// -------------------------------------------------------------------------- +static void WriteNewIndex(IOStream &rDiff, int64_t DiffNumBlocks, FromIndexEntry *pFromIndex, int64_t FromNumBlocks, IOStream &rOut) +{ + // Jump to the end of the diff file to read the index + rDiff.Seek(0 - ((DiffNumBlocks * sizeof(file_BlockIndexEntry)) + sizeof(file_BlockIndexHeader)), IOStream::SeekType_End); + + // Read block index header + file_BlockIndexHeader diffBlkhdr; + if(!rDiff.ReadFullBuffer(&diffBlkhdr, sizeof(diffBlkhdr), 0)) + { + THROW_EXCEPTION(BackupStoreException, FailedToReadBlockOnCombine) + } + if(ntohl(diffBlkhdr.mMagicValue) != OBJECTMAGIC_FILE_BLOCKS_MAGIC_VALUE_V1 + || (int64_t)ntoh64(diffBlkhdr.mNumBlocks) != DiffNumBlocks) + { + THROW_EXCEPTION(BackupStoreException, BadBackupStoreFile) + } + + // Write it out with a blanked out other file ID + diffBlkhdr.mOtherFileID = hton64(0); + rOut.Write(&diffBlkhdr, sizeof(diffBlkhdr)); + + // Rewrite the index + for(int64_t b = 0; b < DiffNumBlocks; ++b) + { + file_BlockIndexEntry en; + if(!rDiff.ReadFullBuffer(&en, sizeof(en), 0)) + { + THROW_EXCEPTION(BackupStoreException, FailedToReadBlockOnCombine) + } + + // What's the size value stored in the entry + int64_t encodedSize = ntoh64(en.mEncodedSize); + + // Need to adjust it? + if(encodedSize <= 0) + { + // This actually refers to a block in the from file. So rewrite this. + int64_t blockIdx = (0 - encodedSize); + if(blockIdx > FromNumBlocks) + { + // References a block which doesn't actually exist + THROW_EXCEPTION(BackupStoreException, BadBackupStoreFile) + } + // Calculate size. This operation is safe because of the extra entry at the end + int32_t blockSize = pFromIndex[blockIdx + 1].mFilePosition - pFromIndex[blockIdx].mFilePosition; + // Then replace entry + en.mEncodedSize = hton64(((uint64_t)blockSize)); + } + + // Write entry + rOut.Write(&en, sizeof(en)); + } +} + + + + + |