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132 lines
4.0 KiB
C++
132 lines
4.0 KiB
C++
// oid.h
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/* Copyright 2009 10gen Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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namespace mongo {
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#pragma pack(1)
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/** Object ID type.
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BSON objects typically have an _id field for the object id. This field should be the first
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member of the object when present. class OID is a special type that is a 12 byte id which
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is likely to be unique to the system. You may also use other types for _id's.
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When _id field is missing from a BSON object, on an insert the database may insert one
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automatically in certain circumstances.
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Warning: You must call OID::newState() after a fork().
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*/
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class OID {
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union {
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struct{
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long long a;
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unsigned b;
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};
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unsigned char data[12];
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};
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static unsigned _machine;
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public:
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/** call this after a fork */
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static void newState();
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/** initialize to 'null' */
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void clear() { a = 0; b = 0; }
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const unsigned char *getData() const { return data; }
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bool operator==(const OID& r) {
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return a==r.a&&b==r.b;
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}
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bool operator!=(const OID& r) {
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return a!=r.a||b!=r.b;
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}
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/** The object ID output as 24 hex digits. */
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string str() const {
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stringstream s;
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s << hex;
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// s.fill( '0' );
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// s.width( 2 );
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// fill wasn't working so doing manually...
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for( int i = 0; i < 8; i++ ) {
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unsigned u = data[i];
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if( u < 16 ) s << '0';
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s << u;
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}
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const unsigned char * raw = (const unsigned char*)&b;
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for( int i = 0; i < 4; i++ ) {
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unsigned u = raw[i];
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if( u < 16 ) s << '0';
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s << u;
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}
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/*
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s.width( 16 );
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s << a;
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s.width( 8 );
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s << b;
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s << dec;
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*/
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return s.str();
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}
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static OID gen() { OID o; o.init(); return o; }
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static unsigned staticMachine(){ return _machine; }
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/**
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sets the contents to a new oid / randomized value
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*/
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void init();
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/** Set to the hex string value specified. */
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void init( string s );
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/** Set to the min/max OID that could be generated at given timestamp. */
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void init( Date_t date, bool max=false );
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time_t asTimeT();
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Date_t asDateT() { return asTimeT() * (long long)1000; }
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bool isSet() const { return a || b; }
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int compare( const OID& other ) const { return memcmp( data , other.data , 12 ); }
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bool operator<( const OID& other ) const { return compare( other ) < 0; }
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};
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#pragma pack()
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ostream& operator<<( ostream &s, const OID &o );
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/** Formatting mode for generating JSON from BSON.
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See <http://mongodb.onconfluence.com/display/DOCS/Mongo+Extended+JSON>
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for details.
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*/
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enum JsonStringFormat {
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/** strict RFC format */
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Strict,
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/** 10gen format, which is close to JS format. This form is understandable by
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javascript running inside the Mongo server via eval() */
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TenGen,
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/** Javascript JSON compatible */
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JS
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};
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inline ostream& operator<<( ostream &s, const OID &o ) {
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s << o.str();
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return s;
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}
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}
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