mirror of https://github.com/facebook/rocksdb.git
122 lines
4.5 KiB
C++
122 lines
4.5 KiB
C++
// Copyright (c) 2013, 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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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#pragma once
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#include <string>
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#include "db/dbformat.h"
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#include "rocksdb/env.h"
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#include "rocksdb/slice.h"
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#include "util/random.h"
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namespace rocksdb {
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namespace test {
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// Store in *dst a random string of length "len" and return a Slice that
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// references the generated data.
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extern Slice RandomString(Random* rnd, int len, std::string* dst);
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extern std::string RandomHumanReadableString(Random* rnd, int len);
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// Return a random key with the specified length that may contain interesting
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// characters (e.g. \x00, \xff, etc.).
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extern std::string RandomKey(Random* rnd, int len);
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// Store in *dst a string of length "len" that will compress to
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// "N*compressed_fraction" bytes and return a Slice that references
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// the generated data.
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extern Slice CompressibleString(Random* rnd, double compressed_fraction,
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int len, std::string* dst);
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// A wrapper that allows injection of errors.
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class ErrorEnv : public EnvWrapper {
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public:
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bool writable_file_error_;
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int num_writable_file_errors_;
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ErrorEnv() : EnvWrapper(Env::Default()),
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writable_file_error_(false),
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num_writable_file_errors_(0) { }
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virtual Status NewWritableFile(const std::string& fname,
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unique_ptr<WritableFile>* result,
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const EnvOptions& soptions) override {
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result->reset();
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if (writable_file_error_) {
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++num_writable_file_errors_;
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return Status::IOError(fname, "fake error");
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}
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return target()->NewWritableFile(fname, result, soptions);
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}
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};
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// An internal comparator that just forward comparing results from the
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// user comparator in it. Can be used to test entities that have no dependency
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// on internal key structure but consumes InternalKeyComparator, like
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// BlockBasedTable.
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class PlainInternalKeyComparator : public InternalKeyComparator {
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public:
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explicit PlainInternalKeyComparator(const Comparator* c)
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: InternalKeyComparator(c) {}
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virtual ~PlainInternalKeyComparator() {}
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virtual int Compare(const Slice& a, const Slice& b) const override {
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return user_comparator()->Compare(a, b);
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}
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virtual void FindShortestSeparator(std::string* start,
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const Slice& limit) const override {
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user_comparator()->FindShortestSeparator(start, limit);
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}
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virtual void FindShortSuccessor(std::string* key) const override {
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user_comparator()->FindShortSuccessor(key);
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}
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};
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// A test comparator which compare two strings in this way:
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// (1) first compare prefix of 8 bytes in alphabet order,
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// (2) if two strings share the same prefix, sort the other part of the string
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// in the reverse alphabet order.
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// This helps simulate the case of compounded key of [entity][timestamp] and
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// latest timestamp first.
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class SimpleSuffixReverseComparator : public Comparator {
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public:
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SimpleSuffixReverseComparator() {}
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virtual const char* Name() const override {
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return "SimpleSuffixReverseComparator";
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}
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virtual int Compare(const Slice& a, const Slice& b) const override {
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Slice prefix_a = Slice(a.data(), 8);
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Slice prefix_b = Slice(b.data(), 8);
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int prefix_comp = prefix_a.compare(prefix_b);
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if (prefix_comp != 0) {
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return prefix_comp;
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} else {
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Slice suffix_a = Slice(a.data() + 8, a.size() - 8);
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Slice suffix_b = Slice(b.data() + 8, b.size() - 8);
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return -(suffix_a.compare(suffix_b));
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}
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}
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virtual void FindShortestSeparator(std::string* start,
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const Slice& limit) const override {}
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virtual void FindShortSuccessor(std::string* key) const override {}
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};
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// Returns a user key comparator that can be used for comparing two uint64_t
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// slices. Instead of comparing slices byte-wise, it compares all the 8 bytes
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// at once. Assumes same endian-ness is used though the database's lifetime.
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// Symantics of comparison would differ from Bytewise comparator in little
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// endian machines.
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extern const Comparator* Uint64Comparator();
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} // namespace test
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} // namespace rocksdb
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