| // 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 <stdio.h> |
| #include "db/dbformat.h" |
| #include "port/port.h" |
| #include "util/coding.h" |
| |
| namespace leveldb { |
| |
| static uint64_t PackSequenceAndType(uint64_t seq, ValueType t) { |
| assert(seq <= kMaxSequenceNumber); |
| assert(t <= kValueTypeForSeek); |
| return (seq << 8) | t; |
| } |
| |
| void AppendInternalKey(std::string* result, const ParsedInternalKey& key) { |
| result->append(key.user_key.data(), key.user_key.size()); |
| PutFixed64(result, PackSequenceAndType(key.sequence, key.type)); |
| } |
| |
| std::string ParsedInternalKey::DebugString() const { |
| char buf[50]; |
| snprintf(buf, sizeof(buf), "' @ %llu : %d", |
| (unsigned long long) sequence, |
| int(type)); |
| std::string result = "'"; |
| result += EscapeString(user_key.ToString()); |
| result += buf; |
| return result; |
| } |
| |
| std::string InternalKey::DebugString() const { |
| std::string result; |
| ParsedInternalKey parsed; |
| if (ParseInternalKey(rep_, &parsed)) { |
| result = parsed.DebugString(); |
| } else { |
| result = "(bad)"; |
| result.append(EscapeString(rep_)); |
| } |
| return result; |
| } |
| |
| const char* InternalKeyComparator::Name() const { |
| return "leveldb.InternalKeyComparator"; |
| } |
| |
| int InternalKeyComparator::Compare(const Slice& akey, const Slice& bkey) const { |
| // Order by: |
| // increasing user key (according to user-supplied comparator) |
| // decreasing sequence number |
| // decreasing type (though sequence# should be enough to disambiguate) |
| int r = user_comparator_->Compare(ExtractUserKey(akey), ExtractUserKey(bkey)); |
| if (r == 0) { |
| const uint64_t anum = DecodeFixed64(akey.data() + akey.size() - 8); |
| const uint64_t bnum = DecodeFixed64(bkey.data() + bkey.size() - 8); |
| if (anum > bnum) { |
| r = -1; |
| } else if (anum < bnum) { |
| r = +1; |
| } |
| } |
| return r; |
| } |
| |
| void InternalKeyComparator::FindShortestSeparator( |
| std::string* start, |
| const Slice& limit) const { |
| // Attempt to shorten the user portion of the key |
| Slice user_start = ExtractUserKey(*start); |
| Slice user_limit = ExtractUserKey(limit); |
| std::string tmp(user_start.data(), user_start.size()); |
| user_comparator_->FindShortestSeparator(&tmp, user_limit); |
| if (tmp.size() < user_start.size() && |
| user_comparator_->Compare(user_start, tmp) < 0) { |
| // User key has become shorter physically, but larger logically. |
| // Tack on the earliest possible number to the shortened user key. |
| PutFixed64(&tmp, PackSequenceAndType(kMaxSequenceNumber,kValueTypeForSeek)); |
| assert(this->Compare(*start, tmp) < 0); |
| assert(this->Compare(tmp, limit) < 0); |
| start->swap(tmp); |
| } |
| } |
| |
| void InternalKeyComparator::FindShortSuccessor(std::string* key) const { |
| Slice user_key = ExtractUserKey(*key); |
| std::string tmp(user_key.data(), user_key.size()); |
| user_comparator_->FindShortSuccessor(&tmp); |
| if (tmp.size() < user_key.size() && |
| user_comparator_->Compare(user_key, tmp) < 0) { |
| // User key has become shorter physically, but larger logically. |
| // Tack on the earliest possible number to the shortened user key. |
| PutFixed64(&tmp, PackSequenceAndType(kMaxSequenceNumber,kValueTypeForSeek)); |
| assert(this->Compare(*key, tmp) < 0); |
| key->swap(tmp); |
| } |
| } |
| |
| const char* InternalFilterPolicy::Name() const { |
| return user_policy_->Name(); |
| } |
| |
| void InternalFilterPolicy::CreateFilter(const Slice* keys, int n, |
| std::string* dst) const { |
| // We rely on the fact that the code in table.cc does not mind us |
| // adjusting keys[]. |
| Slice* mkey = const_cast<Slice*>(keys); |
| for (int i = 0; i < n; i++) { |
| mkey[i] = ExtractUserKey(keys[i]); |
| // TODO(sanjay): Suppress dups? |
| } |
| user_policy_->CreateFilter(keys, n, dst); |
| } |
| |
| bool InternalFilterPolicy::KeyMayMatch(const Slice& key, const Slice& f) const { |
| return user_policy_->KeyMayMatch(ExtractUserKey(key), f); |
| } |
| |
| LookupKey::LookupKey(const Slice& user_key, SequenceNumber s) { |
| size_t usize = user_key.size(); |
| size_t needed = usize + 13; // A conservative estimate |
| char* dst; |
| if (needed <= sizeof(space_)) { |
| dst = space_; |
| } else { |
| dst = new char[needed]; |
| } |
| start_ = dst; |
| dst = EncodeVarint32(dst, usize + 8); |
| kstart_ = dst; |
| memcpy(dst, user_key.data(), usize); |
| dst += usize; |
| EncodeFixed64(dst, PackSequenceAndType(s, kValueTypeForSeek)); |
| dst += 8; |
| end_ = dst; |
| } |
| |
| } // namespace leveldb |