wgtmac commented on code in PR #61:
URL: https://github.com/apache/iceberg-cpp/pull/61#discussion_r2032494097
##########
src/iceberg/transform.h:
##########
@@ -56,14 +56,45 @@ enum class TransformType {
kVoid,
};
+/// \brief Get the relative transform name
+constexpr std::string_view ToString(TransformType type) {
+ switch (type) {
+ case TransformType::kUnknown:
+ return "unknown";
+ case TransformType::kIdentity:
+ return "identity";
+ case TransformType::kBucket:
+ return "bucket";
+ case TransformType::kTruncate:
+ return "truncate";
+ case TransformType::kYear:
+ return "year";
+ case TransformType::kMonth:
+ return "month";
+ case TransformType::kDay:
+ return "day";
+ case TransformType::kHour:
+ return "hour";
+ case TransformType::kVoid:
+ return "void";
+ default:
+ return "invalid";
+ }
+}
+
/// \brief A transform function used for partitioning.
class ICEBERG_EXPORT TransformFunction : public util::Formattable {
public:
- explicit TransformFunction(TransformType type);
+ explicit TransformFunction(TransformType transform_type,
Review Comment:
We can remove `explicit` now
##########
src/iceberg/transform.h:
##########
@@ -56,14 +56,45 @@ enum class TransformType {
kVoid,
};
+/// \brief Get the relative transform name
+constexpr std::string_view ToString(TransformType type) {
+ switch (type) {
+ case TransformType::kUnknown:
+ return "unknown";
+ case TransformType::kIdentity:
+ return "identity";
+ case TransformType::kBucket:
+ return "bucket";
+ case TransformType::kTruncate:
+ return "truncate";
+ case TransformType::kYear:
+ return "year";
+ case TransformType::kMonth:
+ return "month";
+ case TransformType::kDay:
+ return "day";
+ case TransformType::kHour:
+ return "hour";
+ case TransformType::kVoid:
+ return "void";
+ default:
Review Comment:
It seems that we can remove the `default` branch
##########
src/iceberg/transform/transform_spec.h:
##########
@@ -0,0 +1,117 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#pragma once
+
+/// \file iceberg/transform/transform_spec.h
+
+#include <memory>
+#include <optional>
+
+#include "iceberg/arrow_c_data.h"
+#include "iceberg/type_fwd.h"
+
+namespace iceberg {
+/// \brief A specification for creating a TransformFunction instance.
+///
+/// This struct encapsulates all necessary information to describe a transform,
+/// including the type of the transform and any optional parameters it may
require.
+/// It is used by the TransformFactory to instantiate the corresponding
transform
+/// implementation.
+///
+/// For example:
+/// - A Bucket transform with 10 buckets: TransformType::kBucket, params = [10]
+/// - An Identity transform: TransformType::kIdentity, no parameters
+struct TransformSpec {
+ /// \brief The type of the transform (e.g., kBucket, kTruncate, kIdentity,
etc.)
+ TransformType transform_type;
+
+ /// \brief Optional parameter values passed to the transform, represented as
an
+ /// ArrowArray.
+ ///
+ /// For transforms that require parameters (e.g., Bucket(N)), this holds the
arguments
+ /// as a primitive ArrowArray (e.g., INT32 for num_buckets or width).
+ /// If the transform does not require parameters, this will be std::nullopt.
+ std::optional<ArrowArray> params_opt;
Review Comment:
I was thinking about the following approach:
```cpp
struct TransformUtil {
// TODO: source and result types may be required here
static expected<ArrowArray, Error> Copy(const ArrowArray& input);
static expected<ArrowArray, Error> Bucket(const ArrowArray& input, int32_t
num_buckets);
static expected<ArrowArray, Error> Truncate(const ArrowArray& input,
int32_t width);
};
class Transform {
public:
virtual ~Transform() = default;
expected<ArrowArray, Error> Apply(const ArrowArray& input) const {
return transform_function_(input);
}
protected:
Transform(
TransformType transform_type, std::shared_ptr<Type> source_type,
std::shared_ptr<Type> result_type,
std::function<expected<ArrowArray, Error>(const ArrowArray&)>
transform_function)
: Transform(transform_type,
std::vector<std::shared_ptr<Type>>{std::move(source_type)},
std::move(result_type), std::move(transform_function)) {}
Transform(
TransformType transform_type, std::vector<std::shared_ptr<Type>>
source_types,
std::shared_ptr<Type> result_type,
std::function<expected<ArrowArray, Error>(const ArrowArray&)>
transform_function)
: transform_type_(transform_type),
source_types_(std::move(source_types)),
result_type_(std::move(result_type)),
transform_function_(std::move(transform_function)) {}
private:
TransformType transform_type_;
std::vector<std::shared_ptr<Type>> source_types_;
std::shared_ptr<Type> result_type_;
std::function<expected<ArrowArray, Error>(const ArrowArray&)>
transform_function_;
};
class IdentityTransform : public Transform {
public:
explicit IdentityTransform(std::shared_ptr<Type> source_type)
: Transform(TransformType::kIdentity, source_type, source_type,
[](const ArrowArray& input) -> expected<ArrowArray, Error>
{
return TransformUtil::Copy(input);
}) {}
};
class BucketTransform : public Transform {
public:
BucketTransform(std::shared_ptr<Type> source_type, int32_t num_buckets)
:
BucketTransform(std::vector<std::shared_ptr<Type>>{std::move(source_type)},
num_buckets) {}
BucketTransform(std::vector<std::shared_ptr<Type>> source_types, int32_t
num_buckets)
: Transform(TransformType::kBucket, std::move(source_types),
std::make_shared<IntType>(),
[num_buckets](const ArrowArray& input) ->
expected<ArrowArray, Error> {
return TransformUtil::Bucket(input, num_buckets);
}),
num_buckets_{num_buckets} {}
int32_t num_buckets() const { return num_buckets_; }
private:
int32_t num_buckets_;
};
```
WDYT? @gty404 @lidavidm @yingcai-cy
##########
src/iceberg/arrow_c_data.h:
##########
@@ -73,4 +73,44 @@ struct ArrowArray {
#endif // ARROW_C_DATA_INTERFACE
+#ifndef ARROW_C_STREAM_INTERFACE
+# define ARROW_C_STREAM_INTERFACE
+
+struct ArrowArrayStream {
Review Comment:
Why do we need this?
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