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https://issues.apache.org/jira/browse/AVRO-2597?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Marcel Pfütze updated AVRO-2597:
--------------------------------
Description:
In version 1.9.0 GenricDatum.hh was expanded by functionality that was formerly
just in the GenricUnion class.
The following was added:
* isUnion()
* selectBranch()
* unionBranch()
Additionally the methods to access type and value were overwritten to have a
special if case for the union data type:
{code:c++}
inline Type GenericDatum::type() const {
return (type_ == AVRO_UNION) ?
#if __cplusplus >= 201703L
std::any_cast<GenericUnion>(&value_)->datum().type() :
#else
boost::any_cast<GenericUnion>(&value_)->datum().type() :
#endif
type_;
}
template<typename T> T& GenericDatum::value() {
return (type_ == AVRO_UNION) ?
#if __cplusplus >= 201703L
std::any_cast<GenericUnion>(&value_)->datum().value<T>() :
*std::any_cast<T>(&value_);
#else
boost::any_cast<GenericUnion>(&value_)->datum().value<T>() :
*boost::any_cast<T>(&value_);
#endif
}
{code}
The result of this is, that it's impossible to access the GenericUnion from a
GenricDatum as the code always points to the branch of the union.
Currently the only way to get the number of branches this union has, is by
calling selectbranch() in a for-loop until the underlying leafAt() throws an
exception.
In avro 1.8.2 the following code could be used to select a unionbranch of a
specific type.
{code:c++}
inline avro::GenericDatum & select_union_branch(avro::GenericDatum & datum,
const avro::Type type)
{
auto & un = datum.value<avro::GenericUnion>();
auto & schema = un.schema();
auto leaves = schema->leaves();
for(std::size_t i=0; i < leaves; i++) {
if(schema->leafAt(i)->type() == type) {
un.selectBranch(i);
return un.datum();
}
}
throw std::runtime_error(
"select_union_branch: can't find branch with type=" +
std::to_string(type));
}
{code}
My proposals:
# Revert changes to make GenericDatum reflect methods of GenericUnion.
## A Union is a normal data type of Avro like Records or Lists. What is the
point of hiding the type?
## The getters don't just return their value but do an extra check or even cast
before returning. This is counterintuitive.
# Add the schema() method to the GenericDatum class. At least the full
functionality of the GenricUnion should be accessible if you can't access the
GenericUnion itself.
was:
In version 1.9.0 GenricDatum.hh was expanded by functionality that was formerly
just in the GenricUnion class.
The following was added:
* isUnion()
* selectBranch()
* unionBranch()
Additionally the methods to access access type and value were overwritten to
have a special if case for the union data type:
{code:c++}
inline Type GenericDatum::type() const {
return (type_ == AVRO_UNION) ?
#if __cplusplus >= 201703L
std::any_cast<GenericUnion>(&value_)->datum().type() :
#else
boost::any_cast<GenericUnion>(&value_)->datum().type() :
#endif
type_;
}
template<typename T> T& GenericDatum::value() {
return (type_ == AVRO_UNION) ?
#if __cplusplus >= 201703L
std::any_cast<GenericUnion>(&value_)->datum().value<T>() :
*std::any_cast<T>(&value_);
#else
boost::any_cast<GenericUnion>(&value_)->datum().value<T>() :
*boost::any_cast<T>(&value_);
#endif
}
{code}
The result of this is, that it's impossible to access the GenericUnion from a
GenricDatum as the code always points to the branch of the union.
Currently the only way to get the number of branches this union has, is by
calling selectbranch() in a for-loop until the underlying leafAt() throws an
exception.
In avro 1.8.2 the following code could be used to select a unionbranch of a
specific type.
{code:c++}
inline avro::GenericDatum & select_union_branch(avro::GenericDatum & datum,
const avro::Type type)
{
auto & un = datum.value<avro::GenericUnion>();
auto & schema = un.schema();
auto leaves = schema->leaves();
for(std::size_t i=0; i < leaves; i++) {
if(schema->leafAt(i)->type() == type) {
un.selectBranch(i);
return un.datum();
}
}
throw std::runtime_error(
"select_union_branch: can't find branch with type=" +
std::to_string(type));
}
{code}
My proposals:
# Revert changes to make GenericDatum reflect methods of GenericUnion.
## A Union is a normal data type of Avro like Records or Lists. What is the
point of hiding the type?
## The getters don't just return their value but do an extra check or even cast
before returning. This is counterintuitive.
# Add the schema() method to the GenericDatum class. At least the full
functionality of the GenricUnion should be accessible if you can't access the
GenericUnion itself.
> GenricUnion not accessible
> --------------------------
>
> Key: AVRO-2597
> URL: https://issues.apache.org/jira/browse/AVRO-2597
> Project: Apache Avro
> Issue Type: Bug
> Components: c++
> Affects Versions: 1.9.0, 1.9.1
> Reporter: Marcel Pfütze
> Priority: Major
>
> In version 1.9.0 GenricDatum.hh was expanded by functionality that was
> formerly just in the GenricUnion class.
> The following was added:
> * isUnion()
> * selectBranch()
> * unionBranch()
> Additionally the methods to access type and value were overwritten to have a
> special if case for the union data type:
> {code:c++}
> inline Type GenericDatum::type() const {
> return (type_ == AVRO_UNION) ?
> #if __cplusplus >= 201703L
> std::any_cast<GenericUnion>(&value_)->datum().type() :
> #else
> boost::any_cast<GenericUnion>(&value_)->datum().type() :
> #endif
> type_;
> }
> template<typename T> T& GenericDatum::value() {
> return (type_ == AVRO_UNION) ?
> #if __cplusplus >= 201703L
> std::any_cast<GenericUnion>(&value_)->datum().value<T>() :
> *std::any_cast<T>(&value_);
> #else
> boost::any_cast<GenericUnion>(&value_)->datum().value<T>() :
> *boost::any_cast<T>(&value_);
> #endif
> }
> {code}
> The result of this is, that it's impossible to access the GenericUnion from a
> GenricDatum as the code always points to the branch of the union.
> Currently the only way to get the number of branches this union has, is by
> calling selectbranch() in a for-loop until the underlying leafAt() throws an
> exception.
> In avro 1.8.2 the following code could be used to select a unionbranch of a
> specific type.
> {code:c++}
> inline avro::GenericDatum & select_union_branch(avro::GenericDatum & datum,
> const avro::Type type)
> {
> auto & un = datum.value<avro::GenericUnion>();
> auto & schema = un.schema();
> auto leaves = schema->leaves();
> for(std::size_t i=0; i < leaves; i++) {
> if(schema->leafAt(i)->type() == type) {
> un.selectBranch(i);
> return un.datum();
> }
> }
> throw std::runtime_error(
> "select_union_branch: can't find branch with type=" +
> std::to_string(type));
> }
> {code}
> My proposals:
> # Revert changes to make GenericDatum reflect methods of GenericUnion.
> ## A Union is a normal data type of Avro like Records or Lists. What is the
> point of hiding the type?
> ## The getters don't just return their value but do an extra check or even
> cast before returning. This is counterintuitive.
> # Add the schema() method to the GenericDatum class. At least the full
> functionality of the GenricUnion should be accessible if you can't access the
> GenericUnion itself.
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