您最多选择25个主题
主题必须以字母或数字开头，可以包含连字符 (-)，并且长度不得超过35个字符
152 行
4.7 KiB
152 行
4.7 KiB
// 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 += user_key.ToString();
|
|
result += buf;
|
|
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 (user_comparator_->Compare(*start, tmp) < 0) {
|
|
// User key has become larger. 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 (user_comparator_->Compare(user_key, tmp) < 0) {
|
|
// User key has become larger. 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);
|
|
}
|
|
}
|
|
|
|
LargeValueRef LargeValueRef::Make(const Slice& value, CompressionType ctype) {
|
|
LargeValueRef result;
|
|
port::SHA1_Hash(value.data(), value.size(), &result.data[0]);
|
|
EncodeFixed64(&result.data[20], value.size());
|
|
result.data[28] = static_cast<unsigned char>(ctype);
|
|
return result;
|
|
}
|
|
|
|
std::string LargeValueRefToFilenameString(const LargeValueRef& h) {
|
|
assert(sizeof(h.data) == LargeValueRef::ByteSize());
|
|
assert(sizeof(h.data) == 29); // So we can hardcode the array size of buf
|
|
static const char tohex[] = "0123456789abcdef";
|
|
char buf[20*2];
|
|
for (int i = 0; i < 20; i++) {
|
|
buf[2*i] = tohex[(h.data[i] >> 4) & 0xf];
|
|
buf[2*i+1] = tohex[h.data[i] & 0xf];
|
|
}
|
|
std::string result = std::string(buf, sizeof(buf));
|
|
result += "-";
|
|
result += NumberToString(h.ValueSize());
|
|
result += "-";
|
|
result += NumberToString(static_cast<uint64_t>(h.compression_type()));
|
|
return result;
|
|
}
|
|
|
|
static uint32_t hexvalue(char c) {
|
|
if (c >= '0' && c <= '9') {
|
|
return c - '0';
|
|
} else if (c >= 'A' && c <= 'F') {
|
|
return 10 + c - 'A';
|
|
} else {
|
|
assert(c >= 'a' && c <= 'f');
|
|
return 10 + c - 'a';
|
|
}
|
|
}
|
|
|
|
bool FilenameStringToLargeValueRef(const Slice& s, LargeValueRef* h) {
|
|
Slice in = s;
|
|
if (in.size() < 40) {
|
|
return false;
|
|
}
|
|
for (int i = 0; i < 20; i++) {
|
|
if (!isxdigit(in[i*2]) || !isxdigit(in[i*2+1])) {
|
|
return false;
|
|
}
|
|
unsigned char c = (hexvalue(in[i*2])<<4) | hexvalue(in[i*2+1]);
|
|
h->data[i] = c;
|
|
}
|
|
in.remove_prefix(40);
|
|
uint64_t value_size, ctype;
|
|
|
|
if (ConsumeChar(&in, '-') &&
|
|
ConsumeDecimalNumber(&in, &value_size) &&
|
|
ConsumeChar(&in, '-') &&
|
|
ConsumeDecimalNumber(&in, &ctype) &&
|
|
in.empty() &&
|
|
(ctype <= kLightweightCompression)) {
|
|
EncodeFixed64(&h->data[20], value_size);
|
|
h->data[28] = static_cast<unsigned char>(ctype);
|
|
return true;
|
|
} else {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
}
|