leveldb::Table Class Reference

#include <table.h>

Collaboration diagram for leveldb::Table:

Classes
struct	Rep

Public Member Functions
	~Table ()
Iterator *	NewIterator (const ReadOptions &) const
uint64_t	ApproximateOffsetOf (const Slice &key) const

Static Public Member Functions
static Status	Open (const Options &options, RandomAccessFile *file, uint64_t file_size, Table **table)

Private Member Functions
	Table (Rep *rep)
Status	InternalGet (const ReadOptions &, const Slice &key, void *arg, void(*handle_result)(void *arg, const Slice &k, const Slice &v))
void	ReadMeta (const Footer &footer)
void	ReadFilter (const Slice &filter_handle_value)
	Table (const Table &)
void	operator= (const Table &)

Static Private Member Functions
static Iterator *	BlockReader (void *, const ReadOptions &, const Slice &)

Private Attributes
Rep *	rep_

Friends
class	TableCache

Detailed Description

Definition at line 24 of file table.h.

Constructor & Destructor Documentation

~Table()

leveldb::Table::~Table

(

)

Definition at line 143 of file table.cc.

              {
  delete rep_;
}

Table() [1/2]

leveldb::Table::Table ( Rep *  rep )

inlineexplicitprivate

Definition at line 62 of file table.h.

{ rep_ = rep; }

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Table() [2/2]

leveldb::Table::Table ( const Table &  )

private

Member Function Documentation

ApproximateOffsetOf()

uint64_t leveldb::Table::ApproximateOffsetOf

(

const Slice &

key

)

const

Definition at line 258 of file table.cc.

                                                          {
  Iterator* index_iter =
      rep_->index_block->NewIterator(rep_->options.comparator);
  index_iter->Seek(key);
  uint64_t result;
  if (index_iter->Valid()) {
    BlockHandle handle;
    Slice input = index_iter->value();
    Status s = handle.DecodeFrom(&input);
    if (s.ok()) {
      result = handle.offset();
    } else {
      // Strange: we can't decode the block handle in the index block.
      // We'll just return the offset of the metaindex block, which is
      // close to the whole file size for this case.
      result = rep_->metaindex_handle.offset();
    }
  } else {
    // key is past the last key in the file.  Approximate the offset
    // by returning the offset of the metaindex block (which is
    // right near the end of the file).
    result = rep_->metaindex_handle.offset();
  }
  delete index_iter;
  return result;
}

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BlockReader()

Iterator * leveldb::Table::BlockReader ( void *  arg, const ReadOptions &  options, const Slice &  index_value  )

staticprivate

Definition at line 164 of file table.cc.

                                                       {
  Table* table = reinterpret_cast<Table*>(arg);
  Cache* block_cache = table->rep_->options.block_cache;
  Block* block = NULL;
  Cache::Handle* cache_handle = NULL;

  BlockHandle handle;
  Slice input = index_value;
  Status s = handle.DecodeFrom(&input);
  // We intentionally allow extra stuff in index_value so that we
  // can add more features in the future.

  if (s.ok()) {
    BlockContents contents;
    if (block_cache != NULL) {
      char cache_key_buffer[16];
      EncodeFixed64(cache_key_buffer, table->rep_->cache_id);
      EncodeFixed64(cache_key_buffer+8, handle.offset());
      Slice key(cache_key_buffer, sizeof(cache_key_buffer));
      cache_handle = block_cache->Lookup(key);
      if (cache_handle != NULL) {
        block = reinterpret_cast<Block*>(block_cache->Value(cache_handle));
      } else {
        s = ReadBlock(table->rep_->file, options, handle, &contents);
        if (s.ok()) {
          block = new Block(contents);
          if (contents.cachable && options.fill_cache) {
            cache_handle = block_cache->Insert(
                key, block, block->size(), &DeleteCachedBlock);
          }
        }
      }
    } else {
      s = ReadBlock(table->rep_->file, options, handle, &contents);
      if (s.ok()) {
        block = new Block(contents);
      }
    }
  }

  Iterator* iter;
  if (block != NULL) {
    iter = block->NewIterator(table->rep_->options.comparator);
    if (cache_handle == NULL) {
      iter->RegisterCleanup(&DeleteBlock, block, NULL);
    } else {
      iter->RegisterCleanup(&ReleaseBlock, block_cache, cache_handle);
    }
  } else {
    iter = NewErrorIterator(s);
  }
  return iter;
}

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InternalGet()

Status leveldb::Table::InternalGet ( const ReadOptions &  , const Slice &  key, void *  arg, void(*)(void *arg, const Slice &k, const Slice &v)  handle_result  )

private

Definition at line 226 of file table.cc.

                                                                            {
  Status s;
  Iterator* iiter = rep_->index_block->NewIterator(rep_->options.comparator);
  iiter->Seek(k);
  if (iiter->Valid()) {
    Slice handle_value = iiter->value();
    FilterBlockReader* filter = rep_->filter;
    BlockHandle handle;
    if (filter != NULL &&
        handle.DecodeFrom(&handle_value).ok() &&
        !filter->KeyMayMatch(handle.offset(), k)) {
      // Not found
    } else {
      Iterator* block_iter = BlockReader(this, options, iiter->value());
      block_iter->Seek(k);
      if (block_iter->Valid()) {
        (*saver)(arg, block_iter->key(), block_iter->value());
      }
      s = block_iter->status();
      delete block_iter;
    }
  }
  if (s.ok()) {
    s = iiter->status();
  }
  delete iiter;
  return s;
}

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NewIterator()

Iterator * leveldb::Table::NewIterator

(

const ReadOptions &

options

)

const

Definition at line 220 of file table.cc.

                                                             {
  return NewTwoLevelIterator(
      rep_->index_block->NewIterator(rep_->options.comparator),
      &Table::BlockReader, const_cast<Table*>(this), options);
}

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Open()

Status leveldb::Table::Open ( const Options &  options, RandomAccessFile *  file, uint64_t  file_size, Table **  table  )

static

Definition at line 38 of file table.cc.

                                  {
  *table = NULL;
  if (size < Footer::kEncodedLength) {
    return Status::Corruption("file is too short to be an sstable");
  }

  char footer_space[Footer::kEncodedLength];
  Slice footer_input;
  Status s = file->Read(size - Footer::kEncodedLength, Footer::kEncodedLength,
                        &footer_input, footer_space);
  if (!s.ok()) return s;

  Footer footer;
  s = footer.DecodeFrom(&footer_input);
  if (!s.ok()) return s;

  // Read the index block
  BlockContents contents;
  Block* index_block = NULL;
  if (s.ok()) {
    ReadOptions opt;
    if (options.paranoid_checks) {
      opt.verify_checksums = true;
    }
    s = ReadBlock(file, opt, footer.index_handle(), &contents);
    if (s.ok()) {
      index_block = new Block(contents);
    }
  }

  if (s.ok()) {
    // We've successfully read the footer and the index block: we're
    // ready to serve requests.
    Rep* rep = new Table::Rep;
    rep->options = options;
    rep->file = file;
    rep->metaindex_handle = footer.metaindex_handle();
    rep->index_block = index_block;
    rep->cache_id = (options.block_cache ? options.block_cache->NewId() : 0);
    rep->filter_data = NULL;
    rep->filter = NULL;
    *table = new Table(rep);
    (*table)->ReadMeta(footer);
  } else {
    delete index_block;
  }

  return s;
}

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operator=()

void leveldb::Table::operator= ( const Table &  )

private

ReadFilter()

void leveldb::Table::ReadFilter ( const Slice &  filter_handle_value )

private

Definition at line 120 of file table.cc.

                                                       {
  Slice v = filter_handle_value;
  BlockHandle filter_handle;
  if (!filter_handle.DecodeFrom(&v).ok()) {
    return;
  }

  // We might want to unify with ReadBlock() if we start
  // requiring checksum verification in Table::Open.
  ReadOptions opt;
  if (rep_->options.paranoid_checks) {
    opt.verify_checksums = true;
  }
  BlockContents block;
  if (!ReadBlock(rep_->file, opt, filter_handle, &block).ok()) {
    return;
  }
  if (block.heap_allocated) {
    rep_->filter_data = block.data.data();     // Will need to delete later
  }
  rep_->filter = new FilterBlockReader(rep_->options.filter_policy, block.data);
}

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ReadMeta()

void leveldb::Table::ReadMeta ( const Footer &  footer )

private

Definition at line 91 of file table.cc.

                                         {
  if (rep_->options.filter_policy == NULL) {
    return;  // Do not need any metadata
  }

  // TODO(sanjay): Skip this if footer.metaindex_handle() size indicates
  // it is an empty block.
  ReadOptions opt;
  if (rep_->options.paranoid_checks) {
    opt.verify_checksums = true;
  }
  BlockContents contents;
  if (!ReadBlock(rep_->file, opt, footer.metaindex_handle(), &contents).ok()) {
    // Do not propagate errors since meta info is not needed for operation
    return;
  }
  Block* meta = new Block(contents);

  Iterator* iter = meta->NewIterator(BytewiseComparator());
  std::string key = "filter.";
  key.append(rep_->options.filter_policy->Name());
  iter->Seek(key);
  if (iter->Valid() && iter->key() == Slice(key)) {
    ReadFilter(iter->value());
  }
  delete iter;
  delete meta;
}

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Friends And Related Function Documentation

TableCache

friend class TableCache

friend

Definition at line 68 of file table.h.

Member Data Documentation

rep_

Rep* leveldb::Table::rep_

private

Definition at line 59 of file table.h.

---

The documentation for this class was generated from the following files:

• include/leveldb/table.h
• table/table.cc