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https://github.com/facebook/rocksdb.git
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102 lines
3.3 KiB
C++
102 lines
3.3 KiB
C++
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// Copyright (c) 2014, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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#include "table/get_context.h"
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#include "rocksdb/merge_operator.h"
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#include "rocksdb/statistics.h"
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#include "util/statistics.h"
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namespace rocksdb {
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GetContext::GetContext(const Comparator* ucmp,
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const MergeOperator* merge_operator,
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Logger* logger, Statistics* statistics,
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GetState init_state, const Slice& user_key, std::string* ret_value,
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bool* value_found, MergeContext* merge_context)
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: ucmp_(ucmp),
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merge_operator_(merge_operator),
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logger_(logger),
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statistics_(statistics),
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state_(init_state),
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user_key_(user_key),
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value_(ret_value),
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value_found_(value_found),
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merge_context_(merge_context) {
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}
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// Called from TableCache::Get and Table::Get when file/block in which
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// key may exist are not there in TableCache/BlockCache respectively. In this
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// case we can't guarantee that key does not exist and are not permitted to do
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// IO to be certain.Set the status=kFound and value_found=false to let the
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// caller know that key may exist but is not there in memory
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void GetContext::MarkKeyMayExist() {
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state_ = kFound;
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if (value_found_ != nullptr) {
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*value_found_ = false;
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}
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}
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void GetContext::SaveValue(const Slice& value) {
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state_ = kFound;
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value_->assign(value.data(), value.size());
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}
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bool GetContext::SaveValue(const ParsedInternalKey& parsed_key,
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const Slice& value) {
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assert((state_ != kMerge && parsed_key.type != kTypeMerge) ||
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merge_context_ != nullptr);
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if (ucmp_->Compare(parsed_key.user_key, user_key_) == 0) {
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// Key matches. Process it
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switch (parsed_key.type) {
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case kTypeValue:
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assert(state_ == kNotFound || state_ == kMerge);
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if (kNotFound == state_) {
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state_ = kFound;
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value_->assign(value.data(), value.size());
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} else if (kMerge == state_) {
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assert(merge_operator_ != nullptr);
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state_ = kFound;
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if (!merge_operator_->FullMerge(user_key_, &value,
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merge_context_->GetOperands(),
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value_, logger_)) {
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RecordTick(statistics_, NUMBER_MERGE_FAILURES);
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state_ = kCorrupt;
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}
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}
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return false;
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case kTypeDeletion:
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assert(state_ == kNotFound || state_ == kMerge);
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if (kNotFound == state_) {
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state_ = kDeleted;
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} else if (kMerge == state_) {
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state_ = kFound;
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if (!merge_operator_->FullMerge(user_key_, nullptr,
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merge_context_->GetOperands(),
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value_, logger_)) {
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RecordTick(statistics_, NUMBER_MERGE_FAILURES);
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state_ = kCorrupt;
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}
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}
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return false;
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case kTypeMerge:
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assert(state_ == kNotFound || state_ == kMerge);
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state_ = kMerge;
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merge_context_->PushOperand(value);
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return true;
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default:
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assert(false);
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break;
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}
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}
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// state_ could be Corrupt, merge or notfound
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return false;
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}
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} // namespace rocksdb
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