intrusive_ptr<DocumentSource> DocumentSourceGroup::createFromBson(
BSONElement *pBsonElement,
const intrusive_ptr<ExpressionContext> &pCtx) {
uassert(15947, "a group's fields must be specified in an object",
pBsonElement->type() == Object);
intrusive_ptr<DocumentSourceGroup> pGroup(
DocumentSourceGroup::create(pCtx));
bool idSet = false;
BSONObj groupObj(pBsonElement->Obj());
BSONObjIterator groupIterator(groupObj);
while(groupIterator.more()) {
BSONElement groupField(groupIterator.next());
const char *pFieldName = groupField.fieldName();
if (strcmp(pFieldName, Document::idName.c_str()) == 0) {
uassert(15948, "a group's _id may only be specified once",
!idSet);
BSONType groupType = groupField.type();
if (groupType == Object) {
/*
Use the projection-like set of field paths to create the
group-by key.
*/
Expression::ObjectCtx oCtx(
Expression::ObjectCtx::DOCUMENT_OK);
intrusive_ptr<Expression> pId(
Expression::parseObject(&groupField, &oCtx));
pGroup->setIdExpression(pId);
idSet = true;
}
else if (groupType == String) {
string groupString(groupField.String());
const char *pGroupString = groupString.c_str();
if ((groupString.length() == 0) ||
(pGroupString[0] != '$'))
goto StringConstantId;
string pathString(
Expression::removeFieldPrefix(groupString));
intrusive_ptr<ExpressionFieldPath> pFieldPath(
ExpressionFieldPath::create(pathString));
pGroup->setIdExpression(pFieldPath);
idSet = true;
}
else {
/* pick out the constant types that are allowed */
switch(groupType) {
case NumberDouble:
case String:
case Object:
case Array:
case jstOID:
case Bool:
case Date:
case NumberInt:
case Timestamp:
case NumberLong:
case jstNULL:
StringConstantId: // from string case above
{
intrusive_ptr<const Value> pValue(
Value::createFromBsonElement(&groupField));
intrusive_ptr<ExpressionConstant> pConstant(
ExpressionConstant::create(pValue));
pGroup->setIdExpression(pConstant);
idSet = true;
break;
}
default:
uassert(15949, str::stream() <<
"a group's _id may not include fields of BSON type " << groupType,
false);
}
}
}
else {
/*
Treat as a projection field with the additional ability to
add aggregation operators.
*/
uassert(15950, str::stream() <<
"the group aggregate field name " <<
*pFieldName << " cannot be an operator name",
*pFieldName != '$');
uassert(15951, str::stream() <<
"the group aggregate field " << *pFieldName <<
"must be defined as an expression inside an object",
groupField.type() == Object);
BSONObj subField(groupField.Obj());
BSONObjIterator subIterator(subField);
size_t subCount = 0;
for(; subIterator.more(); ++subCount) {
BSONElement subElement(subIterator.next());
/* look for the specified operator */
GroupOpDesc key;
key.pName = subElement.fieldName();
const GroupOpDesc *pOp =
(const GroupOpDesc *)bsearch(
&key, GroupOpTable, NGroupOp, sizeof(GroupOpDesc),
GroupOpDescCmp);
uassert(15952, str::stream() <<
"unknown group operator \"" <<
key.pName << "\"",
pOp);
intrusive_ptr<Expression> pGroupExpr;
BSONType elementType = subElement.type();
if (elementType == Object) {
Expression::ObjectCtx oCtx(
Expression::ObjectCtx::DOCUMENT_OK);
pGroupExpr = Expression::parseObject(
&subElement, &oCtx);
}
else if (elementType == Array) {
uassert(15953, str::stream() <<
"aggregating group operators are unary (" <<
key.pName << ")", false);
}
else { /* assume its an atomic single operand */
pGroupExpr = Expression::parseOperand(&subElement);
}
pGroup->addAccumulator(
pFieldName, pOp->pFactory, pGroupExpr);
}
uassert(15954, str::stream() <<
"the computed aggregate \"" <<
pFieldName << "\" must specify exactly one operator",
subCount == 1);
}
}
uassert(15955, "a group specification must include an _id", idSet);
return pGroup;
}
intrusive_ptr<DocumentSource> DocumentSourceGroup::createFromBson(
BSONElement *pBsonElement,
const intrusive_ptr<ExpressionContext> &pCtx) {
assert(pBsonElement->type() == Object); // CW TODO must be an object
intrusive_ptr<DocumentSourceGroup> pGroup(
DocumentSourceGroup::create(pCtx));
bool idSet = false;
BSONObj groupObj(pBsonElement->Obj());
BSONObjIterator groupIterator(groupObj);
while(groupIterator.more()) {
BSONElement groupField(groupIterator.next());
const char *pFieldName = groupField.fieldName();
if (strcmp(pFieldName, Document::idName.c_str()) == 0) {
assert(!idSet); // CW TODO _id specified multiple times
BSONType groupType = groupField.type();
if (groupType == Object) {
/*
Use the projection-like set of field paths to create the
group-by key.
*/
Expression::ObjectCtx oCtx(
Expression::ObjectCtx::DOCUMENT_OK);
intrusive_ptr<Expression> pId(
Expression::parseObject(&groupField, &oCtx));
pGroup->setIdExpression(pId);
idSet = true;
}
else if (groupType == String) {
string groupString(groupField.String());
const char *pGroupString = groupString.c_str();
if ((groupString.length() == 0) ||
(pGroupString[0] != '$'))
goto StringConstantId;
string pathString(
Expression::removeFieldPrefix(groupString));
intrusive_ptr<ExpressionFieldPath> pFieldPath(
ExpressionFieldPath::create(pathString));
pGroup->setIdExpression(pFieldPath);
idSet = true;
}
else {
/* pick out the constant types that are allowed */
switch(groupType) {
case NumberDouble:
case String:
case Object:
case Array:
case jstOID:
case Bool:
case Date:
case NumberInt:
case Timestamp:
case NumberLong:
case jstNULL:
StringConstantId: // from string case above
{
intrusive_ptr<const Value> pValue(
Value::createFromBsonElement(&groupField));
intrusive_ptr<ExpressionConstant> pConstant(
ExpressionConstant::create(pValue));
pGroup->setIdExpression(pConstant);
idSet = true;
break;
}
default:
assert(false);
// CW TODO disallowed constant group key
}
}
}
else {
/*
Treat as a projection field with the additional ability to
add aggregation operators.
*/
assert(*pFieldName != '$');
// CW TODO error: field name can't be an operator
assert(groupField.type() == Object);
// CW TODO error: must be an operator expression
BSONObj subField(groupField.Obj());
BSONObjIterator subIterator(subField);
size_t subCount = 0;
for(; subIterator.more(); ++subCount) {
BSONElement subElement(subIterator.next());
/* look for the specified operator */
GroupOpDesc key;
key.pName = subElement.fieldName();
const GroupOpDesc *pOp =
(const GroupOpDesc *)bsearch(
&key, GroupOpTable, NGroupOp, sizeof(GroupOpDesc),
GroupOpDescCmp);
assert(pOp); // CW TODO error: operator not found
intrusive_ptr<Expression> pGroupExpr;
BSONType elementType = subElement.type();
if (elementType == Object) {
Expression::ObjectCtx oCtx(
Expression::ObjectCtx::DOCUMENT_OK);
pGroupExpr = Expression::parseObject(
&subElement, &oCtx);
}
else if (elementType == Array) {
assert(false); // CW TODO group operators are unary
}
else { /* assume its an atomic single operand */
pGroupExpr = Expression::parseOperand(&subElement);
}
pGroup->addAccumulator(
pFieldName, pOp->pFactory, pGroupExpr);
}
assert(subCount == 1);
// CW TODO error: only one operator allowed
}
}
assert(idSet); // CW TODO error: missing _id specification
return pGroup;
}