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mongodb/db/jsobj.h

642 lines
16 KiB
C++

/* jsobj.h
BSONObj and its helpers
"BSON" stands for "binary JSON" -- ie a binary way to represent objects that would be
represented in JSON (plus a few extensions useful for databases & other languages).
*/
/**
* Copyright (C) 2008 10gen Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include "../stdafx.h"
#include "../util/builder.h"
#include "boost/utility.hpp"
#include <set>
class BSONObj;
class Record;
class BSONObjBuilder;
#pragma pack(push,1)
/* BinData = binary data types.
EOO = end of object
*/
enum BSONType {MinKey=-1, EOO=0, NumberDouble=1, String=2, Object=3, Array=4, BinData=5,
Undefined=6, jstOID=7, Bool=8, Date=9 , jstNULL=10, RegEx=11 ,
DBRef=12, Code=13, Symbol=14, CodeWScope=15 ,
NumberInt = 16,
JSTypeMax=16,
MaxKey=127
};
/* subtypes of BinData.
bdtCustom and above are ones that the JS compiler understands, but are
opaque to the database.
*/
enum BinDataType { Function=1, ByteArray=2, bdtCustom=128 };
/* Object id's are optional for BSONObjects.
When present they should be the first object member added.
*/
struct OID {
long long a;
unsigned b;
bool operator==(const OID& r) { return a==r.a&&b==r.b; }
void out(){ cout << hex << a << hex << b << endl; };
};
/* marshalled js object format:
<unsigned totalSize> {<byte BSONType><cstring FieldName><Data>}* EOO
totalSize includes itself.
Data:
Bool: <byte>
EOO: nothing follows
Undefined: nothing follows
OID: an OID object
NumberDouble: <double>
NumberInt: <int32>
String: <unsigned32 strsizewithnull><cstring>
Date: <8bytes>
Regex: <cstring regex><cstring options>
Object: a nested object, leading with its entire size, which terminates with EOO.
Array: same as object
DBRef: <strlen> <cstring ns> <oid>
DBRef is a database reference: basically a collection name plus an Object ID
BinData: <int len> <byte subtype> <byte[len] data>
Code: a function (not a closure): same format as String.
Symbol: a language symbol (say a python symbol). same format as String.
Code With Scope: <total size><String><Object>
*/
#pragma pack(pop)
/* <type><fieldName ><value>
-------- size() ------------
-fieldNameSize-
value()
type()
*/
class BSONElement {
friend class BSONObjIterator;
friend class BSONObj;
public:
string toString();
BSONType type() const { return (BSONType) *data; }
bool eoo() const { return type() == EOO; }
int size() const;
// wrap this element up as a singleton object.
BSONObj wrap();
const char * fieldName() const {
if( eoo() ) return ""; // no fieldname for it.
return data + 1;
}
// raw data be careful:
const char * value() const { return (data + fieldNameSize + 1); }
int valuesize() const { return size() - fieldNameSize - 1; }
bool boolean() { return *value() ? true : false; }
unsigned long long date() const { return *((unsigned long long*) value()); }
//double& number() { return *((double *) value()); }
bool isNumber() const { return type() == NumberDouble || type() == NumberInt; }
void setNumber(double d) {
if( type() == NumberDouble ) *((double *) value()) = d;
else if( type() == NumberInt ) *((int *) value()) = (int) d;
}
double number() const {
if( type() == NumberDouble ) return *((double *) value());
if( type() == NumberInt ) return *((int *) value());
return 0;
}
OID& oid() { return *((OID*) value()); }
// for strings
int valuestrsize() const {
return *((int *) value());
}
// for objects the size *includes* the size of the size field
int objsize() const {
return *((int *) value());
}
// for strings. also gives you start of the real data for an embedded object
const char * valuestr() const { return value() + 4; }
const char *valuestrsafe() const {
return type() == String ? valuestr() : "";
}
const char * codeWScopeCode() const { return value() + 8; }
const char * codeWScopeScopeData() const {
// TODO fix
return codeWScopeCode() + strlen( codeWScopeCode() ) + 1;
}
BSONObj embeddedObject();
/* uassert if not an object */
BSONObj embeddedObjectUserCheck();
const char *regex() { assert(type() == RegEx); return value(); }
const char *regexFlags() {
const char *p = regex();
return p + strlen(p) + 1;
}
/* like operator== but doesn't check the fieldname,
just the value.
*/
bool valuesEqual(const BSONElement& r) const {
if( isNumber() )
return number() == r.number() && r.isNumber();
bool match= valuesize() == r.valuesize() &&
memcmp(value(),r.value(),valuesize()) == 0;
return match;
// todo: make "0" == 0.0, undefined==null
}
bool operator==(const BSONElement& r) const {
if( strcmp(fieldName(), r.fieldName()) != 0 )
return false;
return valuesEqual(r);
/*
int sz = size();
return sz == r.size() &&
memcmp(data, r.data, sz) == 0;
*/
}
const char * rawdata() { return data; }
BSONElement();
private:
BSONElement(const char *d) : data(d) {
fieldNameSize = eoo() ? 0 : strlen(fieldName()) + 1;
totalSize = -1;
}
const char *data;
int fieldNameSize;
int totalSize; /* caches the computed size */
};
/* l and r MUST have same type when called: check that first. */
int compareElementValues(const BSONElement& l, const BSONElement& r);
int getGtLtOp(BSONElement& e);
class BSONObj {
friend class BSONObjIterator;
class Details {
public:
~Details() {
// note refCount means two different things (thus the assert here)
assert(refCount <= 0);
if (owned()) {
free((void *)_objdata);
}
_objdata = 0;
}
const char *_objdata;
int _objsize;
int refCount; // -1 == don't free (we don't "own" the buffer)
bool owned() { return refCount >= 0; }
} *details;
void init(const char *data, bool ifree) {
details = new Details();
details->_objdata = data;
details->_objsize = *((int*) data);
assert( details->_objsize > 0 );
assert( details->_objsize <= 1024 * 1024 * 16 );
details->refCount = ifree ? 1 : -1;
}
public:
explicit BSONObj(const char *msgdata, bool ifree = false) {
init(msgdata, ifree);
}
BSONObj(Record *r);
BSONObj() : details(0) { }
~BSONObj() {
if( details ) {
if( --details->refCount <= 0 )
delete details;
details = 0;
}
}
void appendSelfToBufBuilder(BufBuilder& b) {
assert( objsize() );
b.append((void *) objdata(), objsize());
}
/* switch the buffer's ownership to us. */
void iWillFree() {
assert( !details->owned() );
details->refCount = 1;
}
string toString() const;
/* note: addFields always adds _id even if not specified */
int addFields(BSONObj& from, set<string>& fields); /* returns n added */
/* returns # of top level fields in the object
note: iterates to count the fields
*/
int nFields();
/* adds the field names to the fields set. does NOT clear it (appends). */
int getFieldNames(set<string>& fields);
/* return has eoo() true if no match
supports "." notation to reach into embedded objects
*/
BSONElement getFieldDotted(const char *name) const;
BSONElement getField(const char *name) const; /* return has eoo() true if no match */
// returns "" if DNE or wrong type
const char * getStringField(const char *name);
BSONObj getObjectField(const char *name) const;
int getIntField(const char *name); // INT_MIN if not present
bool getBoolField(const char *name);
/* makes a new BSONObj with the fields specified in pattern.
fields returned in the order they appear in pattern.
if any field missing, you get back an empty object overall.
*/
BSONObj extractFieldsDotted(BSONObj pattern, BSONObjBuilder& b); // this version, builder owns the returned obj buffer
BSONObj extractFieldsUnDotted(BSONObj pattern);
BSONObj extractFields(BSONObj &pattern);
const char *objdata() const { return details->_objdata; }
int objsize() const { return details ? details->_objsize : 0; } // includes the embedded size field
bool isEmpty() const { return objsize() <= 5; }
/* sigh...details == 0 is such a pain we have to eliminate that possibility */
void validateEmpty();
void dump() {
cout << hex;
const char *p = objdata();
for( int i = 0; i < objsize(); i++ ) {
cout << i << '\t' << (unsigned) *p;
if( *p >= 'A' && *p <= 'z' )
cout << '\t' << *p;
cout << endl;
p++;
}
}
bool operator<(const BSONObj& r) const { return woCompare(r) < 0; }
/* <0: l<r. 0:l==r. >0:l>r
wo='well ordered'. fields must be in same order in each object.
*/
int woCompare(const BSONObj& r) const;
/* note this is "shallow equality" -- ints and doubles won't match. for a
deep equality test use woCompare (which is slower).
*/
bool woEqual(const BSONObj& r) const {
int os = objsize();
if( os == r.objsize() ) {
return (os == 0 || memcmp(objdata(),r.objdata(),os)==0);
}
return false;
}
bool operator==(const BSONObj& r) const {
return this->woEqual(r);
}
BSONElement firstElement() {
return BSONElement(objdata() + 4);
}
BSONElement findElement(const char *name);
bool hasElement(const char *name);
OID* getOID() {
BSONElement e = firstElement();
if( e.type() != jstOID )
return 0;
return &e.oid();
}
BSONObj(const BSONObj& r) {
if( r.details == 0 )
details = 0;
else if( r.details->owned() ) {
details = r.details;
details->refCount++;
}
else {
details = new Details(*r.details);
}
}
BSONObj& operator=(const BSONObj& r) {
if( details && details->owned() ) {
if( --details->refCount == 0 )
delete details;
}
if( r.details == 0 )
details = 0;
else if( r.details->owned() ) {
details = r.details;
details->refCount++;
}
else {
details = new Details(*r.details);
}
return *this;
}
/* makes a copy of the object. Normally, a jsobj points to data "owned"
by something else. this is a useful way to get your own copy of the buffer
data (which is freed when the new jsobj destructs).
*/
BSONObj copy();
int hash() const {
unsigned x = 0;
const char *p = objdata();
for( int i = 0; i < objsize(); i++ )
x = x * 131 + p[i];
return (x & 0x7fffffff) | 0x8000000; // must be > 0
}
// true unless corrupt
bool valid() const;
};
class BSONObjBuilder {
public:
BSONObjBuilder(int initsize=512) : b(initsize) { b.skip(4); /*leave room for size field*/ }
/* add all the fields from the object specified to this object */
void appendElements(BSONObj x);
void append(BSONElement& e) {
assert( !e.eoo() ); // do not append eoo, that would corrupt us. the builder auto appends when done() is called.
b.append((void*) e.rawdata(), e.size());
}
/* append an element but with a new name */
void appendAs(const BSONElement& e, const char *as) {
b.append((char) e.type());
b.append(as);
b.append((void *) e.value(), e.valuesize());
}
/* add a subobject as a member */
void append(const char *fieldName, BSONObj subObj) {
b.append((char) Object);
b.append(fieldName);
b.append((void *) subObj.objdata(), subObj.objsize());
}
void appendBool(const char *fieldName, int val) {
b.append((char) Bool);
b.append(fieldName);
b.append((char) (val?1:0));
}
void appendInt(const char *fieldName, int n) {
b.append((char) NumberInt);
b.append(fieldName);
b.append(n);
}
void append(const char *fieldName, double n) {
b.append((char) NumberDouble);
b.append(fieldName);
b.append(n);
}
void appendOID(const char *fieldName, OID *oid = 0) {
b.append((char) jstOID);
b.append(fieldName);
b.append((long long) (oid ? oid->a : 0));
b.append((unsigned) (oid ? oid->b : 0));
}
void appendDate(const char *fieldName, unsigned long long dt) {
b.append((char) Date);
b.append(fieldName);
b.append(dt);
}
void append(const char *fieldName, const char *str) {
b.append((char) String);
b.append(fieldName);
b.append((int) strlen(str)+1);
b.append(str);
}
void append(const char *fieldName, string str) {
append(fieldName, str.c_str());
}
// Append an element that is less than all other keys.
void appendMinKey( const char *fieldName ) {
b.append( (char) MinKey );
b.append( fieldName );
}
// Append an element that is greater than all other keys.
void appendMaxKey( const char *fieldName ) {
b.append( (char) MaxKey );
b.append( fieldName );
}
/* BSONObj will free the buffer when it is finished. */
BSONObj doneAndDecouple() {
int l;
return BSONObj(decouple(l), true);
}
/* this version, jsobjbuilder still frees the jsobj
when the builder goes out of scope. use it this way
by default, that's simplest.
*/
BSONObj done() {
return BSONObj(_done());
}
/* assume ownership of the buffer - you must then free it (with free()) */
char* decouple(int& l) {
char *x = _done();
assert( x );
l = b.len();
b.decouple();
return x;
}
void decouple() { b.decouple(); } // post done() call version. be sure jsobj frees...
private:
char* _done() {
b.append((char) EOO);
char *data = b.buf();
*((int*)data) = b.len();
return data;
}
BufBuilder b;
};
/* iterator for a BSONObj
Note each BSONObj ends with an EOO element: so you will get more() on an empty
object, although next().eoo() will be true.
*/
class BSONObjIterator {
public:
BSONObjIterator(const BSONObj& jso) {
int sz = jso.objsize();
if( sz == 0 ) {
pos = theend = 0; return;
}
pos = jso.objdata() + 4;
theend = jso.objdata() + sz;
}
bool more() { return pos < theend; }
BSONElement next() {
BSONElement e(pos);
pos += e.size();
return e;
}
private:
const char *pos;
const char *theend;
};
/* iterator a BSONObj which is an array, in array order.
class JSArrayIter {
public:
BSONObjIterator(const BSONObj& jso) {
...
}
bool more() { return ... }
BSONElement next() {
...
}
};
*/
#include "matcher.h"
extern BSONObj maxKey;
/*- just for testing -- */
#pragma pack(push,1)
struct JSObj1 {
JSObj1() {
totsize=sizeof(JSObj1);
n = NumberDouble; strcpy_s(nname, 5, "abcd"); N = 3.1;
s = String; strcpy_s(sname, 7, "abcdef"); slen = 10;
strcpy_s(sval, 10, "123456789"); eoo = EOO;
}
unsigned totsize;
char n;
char nname[5];
double N;
char s;
char sname[7];
unsigned slen;
char sval[10];
char eoo;
};
#pragma pack(pop)
extern JSObj1 js1;
inline BSONObj BSONElement::embeddedObjectUserCheck() {
uassert( "invalid parameter: expected an object", type()==Object || type()==Array );
return BSONObj(value());
}
inline BSONObj BSONElement::embeddedObject() {
assert( type()==Object || type()==Array );
return BSONObj(value());
}
inline BSONObj BSONObj::copy() {
if( isEmpty() )
return *this;
char *p = (char*) malloc(objsize());
memcpy(p, objdata(), objsize());
return BSONObj(p, true);
}
// wrap this element up as a singleton object.
inline BSONObj BSONElement::wrap() {
BSONObjBuilder b;
b.append(*this);
return b.doneAndDecouple();
}
inline bool BSONObj::hasElement(const char *name) {
if( !isEmpty() ) {
BSONObjIterator it(*this);
while( it.more() ) {
BSONElement e = it.next();
if( strcmp(name, e.fieldName()) == 0 )
return true;
}
}
return false;
}
inline BSONElement BSONObj::findElement(const char *name) {
if( !isEmpty() ) {
BSONObjIterator it(*this);
while( it.more() ) {
BSONElement e = it.next();
if( strcmp(name, e.fieldName()) == 0 )
return e;
}
}
return BSONElement();
}
/* add all the fields from the object specified to this object */
inline void BSONObjBuilder::appendElements(BSONObj x) {
BSONObjIterator it(x);
while( it.more() ) {
BSONElement e = it.next();
if( e.eoo() ) break;
append(e);
}
}
extern BSONObj emptyObj;
inline void BSONObj::validateEmpty() {
if( details == 0 )
*this = emptyObj;
}