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// optime.h - OpTime class
/* 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.
*/
#pragma once
#include <boost/thread/condition.hpp>
namespace mongo {
struct ClockSkewException : public DBException {
ClockSkewException() : DBException( "clock skew exception" , 20001 ) {}
};
/* replsets used to use RSOpTime.
M/S uses OpTime.
But this is useable from both.
*/
typedef unsigned long long ReplTime;
/* Operation sequence #. A combination of current second plus an ordinal value.
*/
#pragma pack(4)
class OpTime {
unsigned i; // ordinal comes first so we can do a single 64 bit compare on little endian
unsigned secs;
static OpTime last;
static OpTime skewed();
public:
static void setLast(const Date_t &date) {
mutex::scoped_lock lk(m);
notifier.notify_all(); // won't really do anything until write-lock released
last = OpTime(date);
}
unsigned getSecs() const {
return secs;
}
unsigned getInc() const {
return i;
}
OpTime(Date_t date) {
reinterpret_cast<unsigned long long&>(*this) = date.millis;
dassert( (int)secs >= 0 );
}
OpTime(ReplTime x) {
reinterpret_cast<unsigned long long&>(*this) = x;
dassert( (int)secs >= 0 );
}
OpTime(unsigned a, unsigned b) {
secs = a;
i = b;
dassert( (int)secs >= 0 );
}
OpTime( const OpTime& other ) {
secs = other.secs;
i = other.i;
dassert( (int)secs >= 0 );
}
OpTime() {
secs = 0;
i = 0;
}
// it isn't generally safe to not be locked for this. so use now(). some tests use this.
static OpTime _now();
static mongo::mutex m;
static OpTime now(const mongo::mutex::scoped_lock&);
static OpTime getLast(const mongo::mutex::scoped_lock&);
// Waits for global OpTime to be different from *this
void waitForDifferent(unsigned millis);
/* We store OpTime's in the database as BSON Date datatype -- we needed some sort of
64 bit "container" for these values. While these are not really "Dates", that seems a
better choice for now than say, Number, which is floating point. Note the BinData type
is perhaps the cleanest choice, lacking a true unsigned64 datatype, but BinData has 5
bytes of overhead.
*/
unsigned long long asDate() const {
return reinterpret_cast<const unsigned long long*>(&i)[0];
}
long long asLL() const {
return reinterpret_cast<const long long*>(&i)[0];
}
bool isNull() const { return secs == 0; }
string toStringLong() const {
char buf[64];
time_t_to_String(secs, buf);
stringstream ss;
ss << time_t_to_String_short(secs) << ' ';
ss << hex << secs << ':' << i;
return ss.str();
}
string toStringPretty() const {
stringstream ss;
ss << time_t_to_String_short(secs) << ':' << hex << i;
return ss.str();
}
string toString() const {
stringstream ss;
ss << hex << secs << ':' << i;
return ss.str();
}
bool operator==(const OpTime& r) const {
return i == r.i && secs == r.secs;
}
bool operator!=(const OpTime& r) const {
return !(*this == r);
}
bool operator<(const OpTime& r) const {
if ( secs != r.secs )
return secs < r.secs;
return i < r.i;
}
bool operator<=(const OpTime& r) const {
return *this < r || *this == r;
}
bool operator>(const OpTime& r) const {
return !(*this <= r);
}
bool operator>=(const OpTime& r) const {
return !(*this < r);
}
private:
static boost::condition notifier;
};
#pragma pack()
} // namespace mongo
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