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Diffstat (limited to 'src/leveldb/db/table_cache.cc')
-rw-r--r-- | src/leveldb/db/table_cache.cc | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/src/leveldb/db/table_cache.cc b/src/leveldb/db/table_cache.cc new file mode 100644 index 0000000000..e3d82cd3ea --- /dev/null +++ b/src/leveldb/db/table_cache.cc @@ -0,0 +1,127 @@ +// 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. + +#include "db/table_cache.h" + +#include "db/filename.h" +#include "leveldb/env.h" +#include "leveldb/table.h" +#include "util/coding.h" + +namespace leveldb { + +struct TableAndFile { + RandomAccessFile* file; + Table* table; +}; + +static void DeleteEntry(const Slice& key, void* value) { + TableAndFile* tf = reinterpret_cast<TableAndFile*>(value); + delete tf->table; + delete tf->file; + delete tf; +} + +static void UnrefEntry(void* arg1, void* arg2) { + Cache* cache = reinterpret_cast<Cache*>(arg1); + Cache::Handle* h = reinterpret_cast<Cache::Handle*>(arg2); + cache->Release(h); +} + +TableCache::TableCache(const std::string& dbname, + const Options* options, + int entries) + : env_(options->env), + dbname_(dbname), + options_(options), + cache_(NewLRUCache(entries)) { +} + +TableCache::~TableCache() { + delete cache_; +} + +Status TableCache::FindTable(uint64_t file_number, uint64_t file_size, + Cache::Handle** handle) { + Status s; + char buf[sizeof(file_number)]; + EncodeFixed64(buf, file_number); + Slice key(buf, sizeof(buf)); + *handle = cache_->Lookup(key); + if (*handle == NULL) { + std::string fname = TableFileName(dbname_, file_number); + RandomAccessFile* file = NULL; + Table* table = NULL; + s = env_->NewRandomAccessFile(fname, &file); + if (!s.ok()) { + std::string old_fname = SSTTableFileName(dbname_, file_number); + if (env_->NewRandomAccessFile(old_fname, &file).ok()) { + s = Status::OK(); + } + } + if (s.ok()) { + s = Table::Open(*options_, file, file_size, &table); + } + + if (!s.ok()) { + assert(table == NULL); + delete file; + // We do not cache error results so that if the error is transient, + // or somebody repairs the file, we recover automatically. + } else { + TableAndFile* tf = new TableAndFile; + tf->file = file; + tf->table = table; + *handle = cache_->Insert(key, tf, 1, &DeleteEntry); + } + } + return s; +} + +Iterator* TableCache::NewIterator(const ReadOptions& options, + uint64_t file_number, + uint64_t file_size, + Table** tableptr) { + if (tableptr != NULL) { + *tableptr = NULL; + } + + Cache::Handle* handle = NULL; + Status s = FindTable(file_number, file_size, &handle); + if (!s.ok()) { + return NewErrorIterator(s); + } + + Table* table = reinterpret_cast<TableAndFile*>(cache_->Value(handle))->table; + Iterator* result = table->NewIterator(options); + result->RegisterCleanup(&UnrefEntry, cache_, handle); + if (tableptr != NULL) { + *tableptr = table; + } + return result; +} + +Status TableCache::Get(const ReadOptions& options, + uint64_t file_number, + uint64_t file_size, + const Slice& k, + void* arg, + void (*saver)(void*, const Slice&, const Slice&)) { + Cache::Handle* handle = NULL; + Status s = FindTable(file_number, file_size, &handle); + if (s.ok()) { + Table* t = reinterpret_cast<TableAndFile*>(cache_->Value(handle))->table; + s = t->InternalGet(options, k, arg, saver); + cache_->Release(handle); + } + return s; +} + +void TableCache::Evict(uint64_t file_number) { + char buf[sizeof(file_number)]; + EncodeFixed64(buf, file_number); + cache_->Erase(Slice(buf, sizeof(buf))); +} + +} // namespace leveldb |