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// @file oid.cpp
/* Copyright 2009 10gen Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "mongo/pch.h"
#include <boost/functional/hash.hpp>
#include "mongo/platform/atomic_word.h"
#include "mongo/platform/random.h"
#include "mongo/bson/bsonobjbuilder.h"
#include "mongo/bson/oid.h"
#include "mongo/bson/util/atomic_int.h"
#define verify MONGO_verify
BOOST_STATIC_ASSERT( sizeof(mongo::OID) == 12 );
namespace mongo {
void OID::hash_combine(size_t &seed) const {
boost::hash_combine(seed, x);
boost::hash_combine(seed, y);
boost::hash_combine(seed, z);
}
// machine # before folding in the process id
OID::MachineAndPid OID::ourMachine;
ostream& operator<<( ostream &s, const OID &o ) {
s << o.str();
return s;
}
unsigned OID::ourPid() {
#ifdef _WIN32
return static_cast<unsigned>( GetCurrentProcessId() );
#else
return static_cast<unsigned>( getpid() );
#endif
}
void OID::foldInPid(OID::MachineAndPid& x) {
unsigned p = ourPid();
x._pid ^= (unsigned short) p;
// when the pid is greater than 16 bits, let the high bits modulate the machine id field.
unsigned short& rest = (unsigned short &) x._machineNumber[1];
rest ^= p >> 16;
}
OID::MachineAndPid OID::genMachineAndPid() {
BOOST_STATIC_ASSERT( sizeof(mongo::OID::MachineAndPid) == 5 );
// we only call this once per process
scoped_ptr<SecureRandom> sr( SecureRandom::create() );
int64_t n = sr->nextInt64();
OID::MachineAndPid x = ourMachine = reinterpret_cast<OID::MachineAndPid&>(n);
foldInPid(x);
return x;
}
// after folding in the process id
OID::MachineAndPid OID::ourMachineAndPid = OID::genMachineAndPid();
void OID::regenMachineId() {
ourMachineAndPid = genMachineAndPid();
}
inline bool OID::MachineAndPid::operator!=(const OID::MachineAndPid& rhs) const {
return _pid != rhs._pid || _machineNumber != rhs._machineNumber;
}
unsigned OID::getMachineId() {
unsigned char x[4];
x[0] = ourMachineAndPid._machineNumber[0];
x[1] = ourMachineAndPid._machineNumber[1];
x[2] = ourMachineAndPid._machineNumber[2];
x[3] = 0;
return (unsigned&) x[0];
}
void OID::justForked() {
MachineAndPid x = ourMachine;
// we let the random # for machine go into all 5 bytes of MachineAndPid, and then
// xor in the pid into _pid. this reduces the probability of collisions.
foldInPid(x);
ourMachineAndPid = genMachineAndPid();
verify( x != ourMachineAndPid );
ourMachineAndPid = x;
}
void OID::init() {
scoped_ptr<SecureRandom> sr( SecureRandom::create() );
static AtomicUInt inc = static_cast<unsigned>( sr->nextInt64() );
{
unsigned t = (unsigned) time(0);
unsigned char *T = (unsigned char *) &t;
_time[0] = T[3]; // big endian order because we use memcmp() to compare OID's
_time[1] = T[2];
_time[2] = T[1];
_time[3] = T[0];
}
_machineAndPid = ourMachineAndPid;
{
int new_inc = inc++;
unsigned char *T = (unsigned char *) &new_inc;
_inc[0] = T[2];
_inc[1] = T[1];
_inc[2] = T[0];
}
}
static AtomicUInt64 _initSequential_sequence;
void OID::initSequential() {
{
unsigned t = (unsigned) time(0);
unsigned char *T = (unsigned char *) &t;
_time[0] = T[3]; // big endian order because we use memcmp() to compare OID's
_time[1] = T[2];
_time[2] = T[1];
_time[3] = T[0];
}
{
unsigned long long nextNumber = _initSequential_sequence.fetchAndAdd(1);
unsigned char* numberData = reinterpret_cast<unsigned char*>(&nextNumber);
for ( int i=0; i<8; i++ ) {
data[4+i] = numberData[7-i];
}
}
}
void OID::init( const std::string& s ) {
verify( s.size() == 24 );
const char *p = s.c_str();
for( int i = 0; i < 12; i++ ) {
data[i] = fromHex(p);
p += 2;
}
}
void OID::init(Date_t date, bool max) {
int time = (int) (date / 1000);
char* T = (char *) &time;
data[0] = T[3];
data[1] = T[2];
data[2] = T[1];
data[3] = T[0];
if (max)
*(long long*)(data + 4) = 0xFFFFFFFFFFFFFFFFll;
else
*(long long*)(data + 4) = 0x0000000000000000ll;
}
time_t OID::asTimeT() {
int time;
char* T = (char *) &time;
T[0] = data[3];
T[1] = data[2];
T[2] = data[1];
T[3] = data[0];
return time;
}
const string BSONObjBuilder::numStrs[] = {
"0", "1", "2", "3", "4", "5", "6", "7", "8", "9",
"10", "11", "12", "13", "14", "15", "16", "17", "18", "19",
"20", "21", "22", "23", "24", "25", "26", "27", "28", "29",
"30", "31", "32", "33", "34", "35", "36", "37", "38", "39",
"40", "41", "42", "43", "44", "45", "46", "47", "48", "49",
"50", "51", "52", "53", "54", "55", "56", "57", "58", "59",
"60", "61", "62", "63", "64", "65", "66", "67", "68", "69",
"70", "71", "72", "73", "74", "75", "76", "77", "78", "79",
"80", "81", "82", "83", "84", "85", "86", "87", "88", "89",
"90", "91", "92", "93", "94", "95", "96", "97", "98", "99",
};
// This is to ensure that BSONObjBuilder doesn't try to use numStrs before the strings have been constructed
// I've tested just making numStrs a char[][], but the overhead of constructing the strings each time was too high
// numStrsReady will be 0 until after numStrs is initialized because it is a static variable
bool BSONObjBuilder::numStrsReady = (numStrs[0].size() > 0);
}
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