lbrycrd/table/iterator_wrapper.h
Pieter Wuille 634ad51703 Squashed 'src/leveldb/' changes from 20ca81f..a31c8aa
a31c8aa Add NewAppendableFile for win32 environment
1913d71 Merge upstream LevelDB 1.19
3080a45 Increase leveldb version to 1.19.
fa6dc01 A zippy change broke test assumptions about the size of compressed output. Fix the tests by allowing more slop in zippy's behavior. ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=123432472
06a191b fix problems in LevelDB's caching code
a7bff69 Fix LevelDB build when asserts are enabled in release builds. (#367)
ea992b4 Change std::uint64_t to uint64_t (#354)
e84b5bd This CL fixes a bug encountered when reading records from leveldb files that have been split, as in a [] input task split.
3211343 Deleted redundant null ptr check prior to delete.
7306ef8 Merge pull request #348 from randomascii/master
6b18316 Fix signed/unsigned mismatch on VC++ builds
adbe3eb Putting build artifacts in subdirectory.
2d0320a Merge pull request #329 from ralphtheninja/travis-badge
dd1c3c3 add travis build badge
43fcf23 Merge pull request #328 from cmumford/master
9fcae61 Added a Travis CI build file.
dac40d2 Merge pull request #284 from ideawu/master
8ec241a Merge pull request #317 from falvojr/patch-1
5d36bed Merge pull request #272 from vapier/master
4753c9b Added a contributors section to README.md
e2446d0 Merge pull request #275 from paulirish/patch-1
706b7f8 Resolve race when getting approximate-memory-usage property
3c9ff3c Only compiling TrimSpace on linux.
f8d205c Including atomic_pointer.h in port_posix
889de31 Let LevelDB use xcrun to determine Xcode.app path instead of using a hardcoded path.
528c2bc Add "approximate-memory-usage" property to leveldb::DB::GetProperty
359b6bc Add leveldb::Cache::Prune
50e77a8 Fix size_t/int comparison/conversion issues in leveldb.
5208e79 Added leveldb::Status::IsInvalidArgument() method.
ce45404 Suppress error reporting after seeking but before a valid First or Full record is encountered.
b9afa1f include <assert> -> <cassert>
edf2939 Update README.md
65190ac Will not reuse manifest if reuse_logs options is false.
ac1d69d LevelDB now attempts to reuse the preceding MANIFEST and log file when re-opened.
76bba13 fix indent
8fcceb2 log compaction output file's level along with number
0e0f074 documentation. improved link
c85addc readme: improved documentation link
ceff6f1 Fix Android/MIPS build.
77948e7 Add benchmark that measures cost of repeatedly opening the database.
34ad72e Move header guard below copyright banner.
a75d435 Clean up layering of storage/leveldb/...
b234f65 Added a new fault injection test.
c4c38f9 Add arm64 support to leveldb.
cea9b10 Fixed incorrect comment wording for Iterator::Seek.
c00c569 Deleted old README file.

git-subtree-dir: src/leveldb
git-subtree-split: a31c8aa408d5594830f7cb20ead1ef1dff51b79e
2016-12-01 16:14:45 -08:00

66 lines
2 KiB
C++

// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_TABLE_ITERATOR_WRAPPER_H_
#define STORAGE_LEVELDB_TABLE_ITERATOR_WRAPPER_H_
#include "leveldb/iterator.h"
#include "leveldb/slice.h"
namespace leveldb {
// A internal wrapper class with an interface similar to Iterator that
// caches the valid() and key() results for an underlying iterator.
// This can help avoid virtual function calls and also gives better
// cache locality.
class IteratorWrapper {
public:
IteratorWrapper(): iter_(NULL), valid_(false) { }
explicit IteratorWrapper(Iterator* iter): iter_(NULL) {
Set(iter);
}
~IteratorWrapper() { delete iter_; }
Iterator* iter() const { return iter_; }
// Takes ownership of "iter" and will delete it when destroyed, or
// when Set() is invoked again.
void Set(Iterator* iter) {
delete iter_;
iter_ = iter;
if (iter_ == NULL) {
valid_ = false;
} else {
Update();
}
}
// Iterator interface methods
bool Valid() const { return valid_; }
Slice key() const { assert(Valid()); return key_; }
Slice value() const { assert(Valid()); return iter_->value(); }
// Methods below require iter() != NULL
Status status() const { assert(iter_); return iter_->status(); }
void Next() { assert(iter_); iter_->Next(); Update(); }
void Prev() { assert(iter_); iter_->Prev(); Update(); }
void Seek(const Slice& k) { assert(iter_); iter_->Seek(k); Update(); }
void SeekToFirst() { assert(iter_); iter_->SeekToFirst(); Update(); }
void SeekToLast() { assert(iter_); iter_->SeekToLast(); Update(); }
private:
void Update() {
valid_ = iter_->Valid();
if (valid_) {
key_ = iter_->key();
}
}
Iterator* iter_;
bool valid_;
Slice key_;
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_TABLE_ITERATOR_WRAPPER_H_