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|
/**
* Copyright (c) 2011 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/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#pragma once
#include "mongo/pch.h"
#include "mongo/db/pipeline/dependencies.h"
#include "mongo/db/pipeline/document.h"
#include "mongo/db/pipeline/field_path.h"
#include "mongo/db/pipeline/value.h"
#include "mongo/util/intrusive_counter.h"
#include "mongo/util/mongoutils/str.h"
#include "mongo/util/string_map.h"
namespace mongo {
class BSONArrayBuilder;
class BSONElement;
class BSONObjBuilder;
class DocumentSource;
// TODO: Look into merging with ExpressionContext and possibly ObjectCtx.
/// The state used as input and working space for Expressions.
class Variables {
MONGO_DISALLOW_COPYING(Variables);
public:
/**
* Each unique variable is assigned a unique id of this type
*/
typedef size_t Id;
// This is only for expressions that use no variables (even ROOT).
Variables() :_numVars(0) {}
explicit Variables(size_t numVars, const Document& root = Document())
: _root(root)
, _rest(numVars == 0 ? NULL : new Value[numVars])
, _numVars(numVars)
{}
static void uassertValidNameForUserWrite(StringData varName);
static void uassertValidNameForUserRead(StringData varName);
static const Id ROOT_ID = Id(-1);
/**
* Use this instead of setValue for setting ROOT
*/
void setRoot(const Document& root) { _root = root; }
void clearRoot() { _root = Document(); }
const Document& getRoot() const { return _root; }
void setValue(Id id, const Value& value);
Value getValue(Id id) const;
/**
* returns Document() for non-document values.
*/
Document getDocument(Id id) const;
private:
Document _root;
const boost::scoped_array<Value> _rest;
const size_t _numVars;
};
/**
* Generates Variables::Ids and keeps track of the number of Ids handed out.
*/
class VariablesIdGenerator {
public:
VariablesIdGenerator() : _nextId(0) {}
Variables::Id generateId() { return _nextId++; }
/**
* Returns the number of Ids handed out by this Generator.
* Return value is intended to be passed to Variables constructor.
*/
Variables::Id getIdCount() const { return _nextId; }
private:
Variables::Id _nextId;
};
/**
* This class represents the Variables that are defined in an Expression tree.
*
* All copies from a given instance share enough information to ensure unique Ids are assigned
* and to propagate back to the original instance enough information to correctly construct a
* Variables instance.
*/
class VariablesParseState {
public:
explicit VariablesParseState(VariablesIdGenerator* idGenerator)
: _idGenerator(idGenerator)
{}
/**
* Assigns a named variable a unique Id. This differs from all other variables, even
* others with the same name.
*
* The special variables ROOT and CURRENT are always implicitly defined with CURRENT
* equivalent to ROOT. If CURRENT is explicitly defined by a call to this function, it
* breaks that equivalence.
*
* NOTE: Name validation is responsibility of caller.
*/
Variables::Id defineVariable(const StringData& name);
/**
* Returns the current Id for a variable. uasserts if the variable isn't defined.
*/
Variables::Id getVariable(const StringData& name) const;
private:
StringMap<Variables::Id> _variables;
VariablesIdGenerator* _idGenerator;
};
class Expression :
public IntrusiveCounterUnsigned {
public:
virtual ~Expression() {};
/*
Optimize the Expression.
This provides an opportunity to do constant folding, or to
collapse nested operators that have the same precedence, such as
$add, $and, or $or.
The Expression should be replaced with the return value, which may
or may not be the same object. In the case of constant folding,
a computed expression may be replaced by a constant.
@returns the optimized Expression
*/
virtual intrusive_ptr<Expression> optimize() { return this; }
/**
* Add this expression's field dependencies to the set
*
* Expressions are trees, so this is often recursive.
*
* @param deps Fully qualified paths to depended-on fields are added to this set.
* Empty string means need full document.
* @param path path to self if all ancestors are ExpressionObjects.
* Top-level ExpressionObject gets pointer to empty vector.
* If any other Expression is an ancestor, or in other cases
* where {a:1} inclusion objects aren't allowed, they get
* NULL.
*/
virtual void addDependencies(DepsTracker* deps, vector<string>* path=NULL) const = 0;
/** simple expressions are just inclusion exclusion as supported by ExpressionObject */
virtual bool isSimple() { return false; }
/**
* Serialize the Expression tree recursively.
* If explain is false, returns a Value parsable by parseOperand().
*/
virtual Value serialize(bool explain) const = 0;
/// Evaluate expression with specified inputs and return result. (only used by tests)
Value evaluate(const Document& root) const {
Variables vars(0, root);
return evaluate(&vars);
}
/**
* Evaluate expression with specified inputs and return result.
*
* While vars is non-const, if properly constructed, subexpressions modifications to it
* should not effect outer expressions due to unique variable Ids.
*/
Value evaluate(Variables* vars) const { return evaluateInternal(vars); }
/*
Utility class for parseObject() below.
DOCUMENT_OK indicates that it is OK to use a Document in the current
context.
*/
class ObjectCtx {
public:
ObjectCtx(int options);
static const int DOCUMENT_OK = 0x0001;
static const int TOP_LEVEL = 0x0002;
static const int INCLUSION_OK = 0x0004;
bool documentOk() const;
bool topLevel() const;
bool inclusionOk() const;
private:
int options;
};
//
// Diagram of relationship between parse functions when parsing a $op:
//
// { someFieldOrArrayIndex: { $op: [ARGS] } }
// ^ parseExpression on inner $op BSONElement
// ^ parseObject on BSONObject
// ^ parseOperand on outer BSONElement wrapping the $op Object
//
/**
* Parses a BSON Object that could represent a functional expression or a Document
* expression.
*/
static intrusive_ptr<Expression> parseObject(
BSONObj obj,
ObjectCtx *pCtx,
const VariablesParseState& vps);
/**
* Parses a BSONElement which has already been determined to be functional expression.
*
* exprElement should be the only element inside the expression object. That is the
* field name should be the $op for the expression.
*/
static intrusive_ptr<Expression> parseExpression(
BSONElement exprElement,
const VariablesParseState& vps);
/**
* Parses a BSONElement which is an operand in an Expression.
*
* This is the most generic parser and can parse ExpressionFieldPath, a literal, or a $op.
* If it is a $op, exprElement should be the outer element whose value is an Object
* containing the $op.
*/
static intrusive_ptr<Expression> parseOperand(
BSONElement exprElement,
const VariablesParseState& vps);
/*
Produce a field path string with the field prefix removed.
Throws an error if the field prefix is not present.
@param prefixedField the prefixed field
@returns the field path with the prefix removed
*/
static string removeFieldPrefix(const string &prefixedField);
/** Evaluate the subclass Expression using the given Variables as context and return result.
*
* Should only be called by subclasses, but can't be protected because they need to call
* this function on each other.
*/
virtual Value evaluateInternal(Variables* vars) const = 0;
protected:
typedef vector<intrusive_ptr<Expression> > ExpressionVector;
};
/// Inherit from ExpressionVariadic or ExpressionFixedArity instead of directly from this class.
class ExpressionNary :
public Expression {
public:
// virtuals from Expression
virtual intrusive_ptr<Expression> optimize();
virtual Value serialize(bool explain) const;
virtual void addDependencies(DepsTracker* deps, vector<string>* path=NULL) const;
/*
Add an operand to the n-ary expression.
@param pExpression the expression to add
*/
virtual void addOperand(const intrusive_ptr<Expression> &pExpression);
// TODO split this into two functions
virtual bool isAssociativeAndCommutative() const { return false; }
/*
Get the name of the operator.
@returns the name of the operator; this string belongs to the class
implementation, and should not be deleted
and should not
*/
virtual const char *getOpName() const = 0;
/// Allow subclasses the opportunity to validate arguments at parse time.
virtual void validateArguments(const ExpressionVector& args) const {}
static ExpressionVector parseArguments(
BSONElement bsonExpr,
const VariablesParseState& vps);
protected:
ExpressionNary() {}
ExpressionVector vpOperand;
};
/// Inherit from ExpressionVariadic or ExpressionFixedArity instead of directly from this class.
template <typename SubClass>
class ExpressionNaryBase : public ExpressionNary {
public:
static intrusive_ptr<Expression> parse(BSONElement bsonExpr,
const VariablesParseState& vps) {
intrusive_ptr<ExpressionNaryBase> expr = new SubClass();
ExpressionVector args = parseArguments(bsonExpr, vps);
expr->validateArguments(args);
expr->vpOperand = args;
return expr;
}
};
/// Inherit from this class if your expression takes a variable number of arguments.
template <typename SubClass>
class ExpressionVariadic : public ExpressionNaryBase<SubClass> {
};
/// Inherit from this class if your expression takes a fixed number of arguments.
template <typename SubClass, int NArgs>
class ExpressionFixedArity : public ExpressionNaryBase<SubClass> {
public:
virtual void validateArguments(const Expression::ExpressionVector& args) const {
uassert(16020, mongoutils::str::stream()
<< "Expression " << this->getOpName() << " takes exactly " << NArgs
<< " arguments. " << args.size() << " were passed in.",
args.size() == NArgs);
}
};
class ExpressionAdd : public ExpressionVariadic<ExpressionAdd> {
public:
// virtuals from Expression
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
virtual bool isAssociativeAndCommutative() const { return true; }
};
class ExpressionAllElementsTrue : public ExpressionFixedArity<ExpressionAllElementsTrue, 1> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionAnd : public ExpressionVariadic<ExpressionAnd> {
public:
// virtuals from Expression
virtual intrusive_ptr<Expression> optimize();
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
virtual bool isAssociativeAndCommutative() const { return true; }
};
class ExpressionAnyElementTrue : public ExpressionFixedArity<ExpressionAnyElementTrue, 1> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionCoerceToBool : public Expression {
public:
// virtuals from ExpressionNary
virtual intrusive_ptr<Expression> optimize();
virtual void addDependencies(DepsTracker* deps, vector<string>* path=NULL) const;
virtual Value evaluateInternal(Variables* vars) const;
virtual Value serialize(bool explain) const;
static intrusive_ptr<ExpressionCoerceToBool> create(
const intrusive_ptr<Expression> &pExpression);
private:
ExpressionCoerceToBool(const intrusive_ptr<Expression> &pExpression);
intrusive_ptr<Expression> pExpression;
};
class ExpressionCompare : public ExpressionFixedArity<ExpressionCompare, 2> {
public:
/** Enumeration of comparison operators. Any changes to these values require adjustment of
* the lookup table in the implementation.
*/
enum CmpOp {
EQ = 0, // return true for a == b, false otherwise
NE = 1, // return true for a != b, false otherwise
GT = 2, // return true for a > b, false otherwise
GTE = 3, // return true for a >= b, false otherwise
LT = 4, // return true for a < b, false otherwise
LTE = 5, // return true for a <= b, false otherwise
CMP = 6, // return -1, 0, 1 for a < b, a == b, a > b
};
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
static intrusive_ptr<Expression> parse(
BSONElement bsonExpr,
const VariablesParseState& vps,
CmpOp cmpOp);
ExpressionCompare(CmpOp cmpOp);
private:
CmpOp cmpOp;
};
class ExpressionConcat : public ExpressionVariadic<ExpressionConcat> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionCond : public ExpressionFixedArity<ExpressionCond, 3> {
typedef ExpressionFixedArity<ExpressionCond, 3> Base;
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
static intrusive_ptr<Expression> parse(
BSONElement expr,
const VariablesParseState& vps);
};
class ExpressionConstant : public Expression {
public:
// virtuals from Expression
virtual intrusive_ptr<Expression> optimize();
virtual void addDependencies(DepsTracker* deps, vector<string>* path=NULL) const;
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
virtual Value serialize(bool explain) const;
static intrusive_ptr<ExpressionConstant> create(const Value& pValue);
static intrusive_ptr<Expression> parse(
BSONElement bsonExpr,
const VariablesParseState& vps);
/*
Get the constant value represented by this Expression.
@returns the value
*/
Value getValue() const;
private:
ExpressionConstant(const Value& pValue);
Value pValue;
};
class ExpressionDayOfMonth : public ExpressionFixedArity<ExpressionDayOfMonth, 1> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionDayOfWeek : public ExpressionFixedArity<ExpressionDayOfWeek, 1> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionDayOfYear : public ExpressionFixedArity<ExpressionDayOfYear, 1> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionDivide : public ExpressionFixedArity<ExpressionDivide, 2> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionFieldPath : public Expression {
public:
// virtuals from Expression
virtual intrusive_ptr<Expression> optimize();
virtual void addDependencies(DepsTracker* deps, vector<string>* path=NULL) const;
virtual Value evaluateInternal(Variables* vars) const;
virtual Value serialize(bool explain) const;
/*
Create a field path expression using old semantics (rooted off of CURRENT).
// NOTE: this method is deprecated and only used by tests
// TODO remove this method in favor of parse()
Evaluation will extract the value associated with the given field
path from the source document.
@param fieldPath the field path string, without any leading document
indicator
@returns the newly created field path expression
*/
static intrusive_ptr<ExpressionFieldPath> create(const string& fieldPath);
/// Like create(), but works with the raw string from the user with the "$" prefixes.
static intrusive_ptr<ExpressionFieldPath> parse(
const string& raw,
const VariablesParseState& vps);
const FieldPath& getFieldPath() const { return _fieldPath; }
private:
ExpressionFieldPath(const string& fieldPath, Variables::Id variable);
/*
Internal implementation of evaluateInternal(), used recursively.
The internal implementation doesn't just use a loop because of
the possibility that we need to skip over an array. If the path
is "a.b.c", and a is an array, then we fan out from there, and
traverse "b.c" for each element of a:[...]. This requires that
a be an array of objects in order to navigate more deeply.
@param index current path field index to extract
@param input current document traversed to (not the top-level one)
@returns the field found; could be an array
*/
Value evaluatePath(size_t index, const Document& input) const;
// Helper for evaluatePath to handle Array case
Value evaluatePathArray(size_t index, const Value& input) const;
const FieldPath _fieldPath;
const Variables::Id _variable;
};
class ExpressionHour : public ExpressionFixedArity<ExpressionHour, 1> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionIfNull : public ExpressionFixedArity<ExpressionIfNull, 2> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionLet : public Expression {
public:
// virtuals from Expression
virtual intrusive_ptr<Expression> optimize();
virtual Value serialize(bool explain) const;
virtual Value evaluateInternal(Variables* vars) const;
virtual void addDependencies(DepsTracker* deps, vector<string>* path=NULL) const;
static intrusive_ptr<Expression> parse(
BSONElement expr,
const VariablesParseState& vps);
struct NameAndExpression {
NameAndExpression() {}
NameAndExpression(string name, intrusive_ptr<Expression> expression)
: name(name)
, expression(expression)
{}
string name;
intrusive_ptr<Expression> expression;
};
typedef map<Variables::Id, NameAndExpression> VariableMap;
private:
ExpressionLet(const VariableMap& vars,
intrusive_ptr<Expression> subExpression);
VariableMap _variables;
intrusive_ptr<Expression> _subExpression;
};
class ExpressionMap : public Expression {
public:
// virtuals from Expression
virtual intrusive_ptr<Expression> optimize();
virtual Value serialize(bool explain) const;
virtual Value evaluateInternal(Variables* vars) const;
virtual void addDependencies(DepsTracker* deps, vector<string>* path=NULL) const;
static intrusive_ptr<Expression> parse(
BSONElement expr,
const VariablesParseState& vps);
private:
ExpressionMap(const string& varName, // name of variable to set
Variables::Id varId, // id of variable to set
intrusive_ptr<Expression> input, // yields array to iterate
intrusive_ptr<Expression> each); // yields results to be added to output array
string _varName;
Variables::Id _varId;
intrusive_ptr<Expression> _input;
intrusive_ptr<Expression> _each;
};
class ExpressionMeta : public Expression {
public:
// virtuals from Expression
virtual Value serialize(bool explain) const;
virtual Value evaluateInternal(Variables* vars) const;
virtual void addDependencies(DepsTracker* deps, vector<string>* path=NULL) const;
static intrusive_ptr<Expression> parse(
BSONElement expr,
const VariablesParseState& vps);
};
class ExpressionMillisecond : public ExpressionFixedArity<ExpressionMillisecond, 1> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char* getOpName() const;
};
class ExpressionMinute : public ExpressionFixedArity<ExpressionMinute, 1> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionMod : public ExpressionFixedArity<ExpressionMod, 2> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionMultiply : public ExpressionVariadic<ExpressionMultiply> {
public:
// virtuals from Expression
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
virtual bool isAssociativeAndCommutative() const { return true; }
};
class ExpressionMonth : public ExpressionFixedArity<ExpressionMonth, 1> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionNot : public ExpressionFixedArity<ExpressionNot, 1> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionObject : public Expression {
public:
// virtuals from Expression
virtual intrusive_ptr<Expression> optimize();
virtual bool isSimple();
virtual void addDependencies(DepsTracker* deps, vector<string>* path=NULL) const;
/** Only evaluates non inclusion expressions. For inclusions, use addToDocument(). */
virtual Value evaluateInternal(Variables* vars) const;
virtual Value serialize(bool explain) const;
/// like evaluate(), but return a Document instead of a Value-wrapped Document.
Document evaluateDocument(Variables* vars) const;
/** Evaluates with inclusions and adds results to passed in Mutable document
*
* @param output the MutableDocument to add the evaluated expressions to
* @param currentDoc the input Document for this level (for inclusions)
* @param vars the variables for use in subexpressions
*/
void addToDocument(MutableDocument& ouput,
const Document& currentDoc,
Variables* vars
) const;
// estimated number of fields that will be output
size_t getSizeHint() const;
/** Create an empty expression.
* Until fields are added, this will evaluate to an empty document.
*/
static intrusive_ptr<ExpressionObject> create();
/// Like create but uses special handling of _id for root object of $project.
static intrusive_ptr<ExpressionObject> createRoot();
/*
Add a field to the document expression.
@param fieldPath the path the evaluated expression will have in the
result Document
@param pExpression the expression to evaluate obtain this field's
Value in the result Document
*/
void addField(const FieldPath &fieldPath,
const intrusive_ptr<Expression> &pExpression);
/*
Add a field path to the set of those to be included.
Note that including a nested field implies including everything on
the path leading down to it.
@param fieldPath the name of the field to be included
*/
void includePath(const string &fieldPath);
/*
Get a count of the added fields.
@returns how many fields have been added
*/
size_t getFieldCount() const;
/*
Specialized BSON conversion that allows for writing out a
$project specification. This creates a standalone object, which must
be added to a containing object with a name
@param pBuilder where to write the object to
@param requireExpression see Expression::addToBsonObj
*/
void documentToBson(BSONObjBuilder *pBuilder,
bool requireExpression) const;
/*
Visitor abstraction used by emitPaths(). Each path is recorded by
calling path().
*/
class PathSink {
public:
virtual ~PathSink() {};
/**
Record a path.
@param path the dotted path string
@param include if true, the path is included; if false, the path
is excluded
*/
virtual void path(const string &path, bool include) = 0;
};
void excludeId(bool b) { _excludeId = b; }
private:
ExpressionObject(bool atRoot);
// Mapping from fieldname to the Expression that generates its value.
// NULL expression means inclusion from source document.
typedef map<string, intrusive_ptr<Expression> > FieldMap;
FieldMap _expressions;
// this is used to maintain order for generated fields not in the source document
vector<string> _order;
bool _excludeId;
bool _atRoot;
};
class ExpressionOr : public ExpressionVariadic<ExpressionOr> {
public:
// virtuals from Expression
virtual intrusive_ptr<Expression> optimize();
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
virtual bool isAssociativeAndCommutative() const { return true; }
};
class ExpressionSecond : public ExpressionFixedArity<ExpressionSecond, 1> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionSetDifference : public ExpressionFixedArity<ExpressionSetDifference, 2> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionSetEquals : public ExpressionVariadic<ExpressionSetEquals> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
virtual void validateArguments(const ExpressionVector& args) const;
};
class ExpressionSetIntersection : public ExpressionVariadic<ExpressionSetIntersection> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
virtual bool isAssociativeAndCommutative() const { return true; }
};
class ExpressionSetIsSubset : public ExpressionFixedArity<ExpressionSetIsSubset, 2> {
public:
// virtuals from ExpressionNary
virtual intrusive_ptr<Expression> optimize();
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
private:
class Optimized;
};
class ExpressionSetUnion : public ExpressionVariadic<ExpressionSetUnion> {
public:
// virtuals from ExpressionNary
// virtual intrusive_ptr<Expression> optimize();
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
virtual bool isAssociativeAndCommutative() const { return true; }
};
class ExpressionSize : public ExpressionFixedArity<ExpressionSize, 1> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionStrcasecmp : public ExpressionFixedArity<ExpressionStrcasecmp, 2> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionSubstr : public ExpressionFixedArity<ExpressionSubstr, 3> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionSubtract : public ExpressionFixedArity<ExpressionSubtract, 2> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionToLower : public ExpressionFixedArity<ExpressionToLower, 1> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionToUpper : public ExpressionFixedArity<ExpressionToUpper, 1> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionWeek : public ExpressionFixedArity<ExpressionWeek, 1> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
class ExpressionYear : public ExpressionFixedArity<ExpressionYear, 1> {
public:
// virtuals from ExpressionNary
virtual Value evaluateInternal(Variables* vars) const;
virtual const char *getOpName() const;
};
}
/* ======================= INLINED IMPLEMENTATIONS ========================== */
namespace mongo {
inline Value ExpressionConstant::getValue() const {
return pValue;
}
inline size_t ExpressionObject::getFieldCount() const {
return _expressions.size();
}
}
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