72502cf227
Summary:
This reverts the previous commit 1d7048c598, which broke the build.
Did a `git revert 1d7048c`.
Closes https://github.com/facebook/rocksdb/pull/2627
Differential Revision: D5476473
Pulled By: sagar0
fbshipit-source-id: 4756ff5c0dfc88c17eceb00e02c36176de728d06
118 lines
3.4 KiB
C++
118 lines
3.4 KiB
C++
/**
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* @author Deon Nicholas (dnicholas@fb.com)
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* Copyright 2013 Facebook
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*/
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#include "stringappend2.h"
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#include <memory>
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#include <string>
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#include <assert.h>
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#include "rocksdb/slice.h"
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#include "rocksdb/merge_operator.h"
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#include "utilities/merge_operators.h"
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namespace rocksdb {
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// Constructor: also specify the delimiter character.
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StringAppendTESTOperator::StringAppendTESTOperator(char delim_char)
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: delim_(delim_char) {
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}
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// Implementation for the merge operation (concatenates two strings)
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bool StringAppendTESTOperator::FullMergeV2(
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const MergeOperationInput& merge_in,
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MergeOperationOutput* merge_out) const {
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// Clear the *new_value for writing.
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merge_out->new_value.clear();
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if (merge_in.existing_value == nullptr && merge_in.operand_list.size() == 1) {
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// Only one operand
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merge_out->existing_operand = merge_in.operand_list.back();
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return true;
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}
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// Compute the space needed for the final result.
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size_t numBytes = 0;
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for (auto it = merge_in.operand_list.begin();
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it != merge_in.operand_list.end(); ++it) {
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numBytes += it->size() + 1; // Plus 1 for the delimiter
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}
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// Only print the delimiter after the first entry has been printed
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bool printDelim = false;
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// Prepend the *existing_value if one exists.
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if (merge_in.existing_value) {
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merge_out->new_value.reserve(numBytes + merge_in.existing_value->size());
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merge_out->new_value.append(merge_in.existing_value->data(),
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merge_in.existing_value->size());
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printDelim = true;
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} else if (numBytes) {
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merge_out->new_value.reserve(
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numBytes - 1); // Minus 1 since we have one less delimiter
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}
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// Concatenate the sequence of strings (and add a delimiter between each)
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for (auto it = merge_in.operand_list.begin();
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it != merge_in.operand_list.end(); ++it) {
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if (printDelim) {
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merge_out->new_value.append(1, delim_);
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}
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merge_out->new_value.append(it->data(), it->size());
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printDelim = true;
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}
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return true;
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}
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bool StringAppendTESTOperator::PartialMergeMulti(
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const Slice& key, const std::deque<Slice>& operand_list,
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std::string* new_value, Logger* logger) const {
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return false;
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}
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// A version of PartialMerge that actually performs "partial merging".
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// Use this to simulate the exact behaviour of the StringAppendOperator.
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bool StringAppendTESTOperator::_AssocPartialMergeMulti(
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const Slice& key, const std::deque<Slice>& operand_list,
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std::string* new_value, Logger* logger) const {
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// Clear the *new_value for writing
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assert(new_value);
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new_value->clear();
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assert(operand_list.size() >= 2);
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// Generic append
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// Determine and reserve correct size for *new_value.
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size_t size = 0;
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for (const auto& operand : operand_list) {
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size += operand.size();
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}
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size += operand_list.size() - 1; // Delimiters
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new_value->reserve(size);
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// Apply concatenation
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new_value->assign(operand_list.front().data(), operand_list.front().size());
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for (std::deque<Slice>::const_iterator it = operand_list.begin() + 1;
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it != operand_list.end(); ++it) {
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new_value->append(1, delim_);
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new_value->append(it->data(), it->size());
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}
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return true;
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}
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const char* StringAppendTESTOperator::Name() const {
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return "StringAppendTESTOperator";
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}
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std::shared_ptr<MergeOperator>
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MergeOperators::CreateStringAppendTESTOperator() {
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return std::make_shared<StringAppendTESTOperator>(',');
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}
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} // namespace rocksdb
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