Fokko commented on code in PR #112: URL: https://github.com/apache/iceberg-cpp/pull/112#discussion_r2182145745
########## src/iceberg/table_scan.h: ########## @@ -0,0 +1,210 @@ +/* + * 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 + +#include <string> +#include <vector> + +#include "iceberg/manifest_entry.h" +#include "iceberg/type_fwd.h" + +namespace iceberg { + +/// \brief An abstract scan task. +class ICEBERG_EXPORT ScanTask { + public: + virtual ~ScanTask() = default; + + /// \brief The number of bytes that should be read by this scan task. + virtual int64_t SizeBytes() const = 0; + + /// \brief The number of files that should be read by this scan task. + virtual int32_t FilesCount() const = 0; + + /// \brief The number of rows that should be read by this scan task. + virtual int64_t EstimatedRowCount() const = 0; +}; + +/// \brief Task representing a data file and its corresponding delete files. +class ICEBERG_EXPORT FileScanTask : public ScanTask { + public: + FileScanTask(std::shared_ptr<DataFile> file, + std::vector<std::shared_ptr<DataFile>> delete_files, int64_t start, + int64_t length, std::shared_ptr<Expression> residual); + + /// \brief The data file that should be read by this scan task. + const std::shared_ptr<DataFile>& data_file() const; + + /// \brief The delete files that should be read by this scan task. + const std::vector<std::shared_ptr<DataFile>>& delete_files() const; + + /// \brief The byte offset in the data file where the scan should start. + int64_t start() const; + + /// \brief The length in bytes to scan from the start offset. + int64_t length() const; + + /// \brief The residual expression to apply after scanning the data file. + const std::shared_ptr<Expression>& residual() const; + + int64_t SizeBytes() const override; + int32_t FilesCount() const override; + int64_t EstimatedRowCount() const override; + + private: + /// \brief Data file metadata. + std::shared_ptr<DataFile> data_file_; + /// \brief Delete files metadata. + std::vector<std::shared_ptr<DataFile>> delete_files_; + /// \brief Start byte offset. + int64_t start_; + /// \brief Length in bytes to scan. + int64_t length_; + /// \brief Residual expression to apply. + std::shared_ptr<Expression> residual_; +}; + +/// \brief Scan context holding snapshot and scan-specific metadata. +struct TableScanContext { + /// \brief Table metadata. + std::shared_ptr<TableMetadata> table_metadata; + /// \brief Snapshot to scan. + std::shared_ptr<Snapshot> snapshot; + /// \brief Projected schema. + std::shared_ptr<Schema> projected_schema; + /// \brief Filter expression to apply. + std::shared_ptr<Expression> filter; + /// \brief Whether the scan is case-sensitive. + bool case_sensitive = false; + /// \brief Additional options for the scan. + std::unordered_map<std::string, std::string> options; + /// \brief Optional limit on the number of rows to scan. + std::optional<int64_t> limit; +}; + +/// \brief Builder class for creating TableScan instances. +class ICEBERG_EXPORT TableScanBuilder { + public: + /// \brief Constructs a TableScanBuilder for the given table. + /// \param table_metadata The metadata of the table to scan. + /// \param file_io The FileIO instance for reading manifests and data files. + explicit TableScanBuilder(std::shared_ptr<TableMetadata> table_metadata, + std::shared_ptr<FileIO> file_io); + + /// \brief Sets the snapshot ID to scan. + /// \param snapshot_id The ID of the snapshot. + /// \return Reference to the builder. + TableScanBuilder& WithSnapshotId(int64_t snapshot_id); + + /// \brief Selects columns to include in the scan. + /// \param column_names A list of column names. If empty, all columns will be selected. + /// \return Reference to the builder. + TableScanBuilder& WithColumnNames(std::vector<std::string> column_names); + + /// \brief Sets the schema to use for the scan. + /// \param schema The schema to use. + /// \return Reference to the builder. + TableScanBuilder& WithProjectedSchema(std::shared_ptr<Schema> schema); + + /// \brief Applies a filter expression to the scan. + /// \param filter Filter expression to use. + /// \return Reference to the builder. + TableScanBuilder& WithFilter(std::shared_ptr<Expression> filter); + + /// \brief Sets whether the scan should be case-sensitive. + /// \param case_sensitive Whether the scan is case-sensitive. + /// /return Reference to the builder. + TableScanBuilder& WithCaseSensitive(bool case_sensitive); + + /// \brief Sets an option for the scan. + /// \param property The name of the option. + /// \param value The value of the option. + /// \return Reference to the builder. + TableScanBuilder& WithOption(std::string property, std::string value); + + /// \brief Sets an optional limit on the number of rows to scan. + /// \param limit Optional limit on the number of rows. + /// \return Reference to the builder. + TableScanBuilder& WithLimit(std::optional<int64_t> limit); + + /// \brief Builds and returns a TableScan instance. + /// \return A Result containing the TableScan or an error. + Result<std::unique_ptr<TableScan>> Build(); + + private: + /// \brief the file I/O instance for reading manifests and data files. + std::shared_ptr<FileIO> file_io_; + /// \brief column names to project in the scan. + std::vector<std::string> column_names_; + /// \brief snapshot ID to scan, if specified. + std::optional<int64_t> snapshot_id_; + /// \brief Context for the scan, including snapshot, schema, and filter. + TableScanContext context_; +}; + +/// \brief Represents a configured scan operation on a table. +class ICEBERG_EXPORT TableScan { + public: + virtual ~TableScan() = default; + + /// \brief Constructs a TableScan with the given context and file I/O. + /// \param context Scan context including snapshot, schema, and filter. + /// \param file_io File I/O instance for reading manifests and data files. + TableScan(TableScanContext context, std::shared_ptr<FileIO> file_io); + + /// \brief Returns the snapshot being scanned. + /// \return A shared pointer to the snapshot. + const std::shared_ptr<Snapshot>& snapshot() const; + + /// \brief Returns the projected schema for the scan. + /// \return A shared pointer to the projected schema. + const std::shared_ptr<Schema>& projection() const; + + /// \brief Returns the scan context. + /// \return A reference to the TableScanContext. + const TableScanContext& context() const; + + /// \brief Returns the file I/O instance used for reading manifests and data files. + /// \return A shared pointer to the FileIO instance. + const std::shared_ptr<FileIO>& io() const; + + /// \brief Plans the scan tasks by resolving manifests and data files. + /// \return A Result containing scan tasks or an error. + virtual Result<std::vector<std::shared_ptr<FileScanTask>>> PlanFiles() const = 0; + + protected: + /// \brief context for the scan, including snapshot, schema, and filter. + const TableScanContext context_; + /// \brief File I/O instance for reading manifests and data files. + std::shared_ptr<FileIO> file_io_; +}; + +/// \brief A scan that reads data files and applies delete files to filter rows. +class ICEBERG_EXPORT DataScan : public TableScan { Review Comment: At PyIceberg we (tried to) copied the Java structure, but in the end I think it is too much OOP for Python. Maybe good to start small in C++ as well. While we can change APIs until 1.0.0, I think it is important to get this one right pretty early on, since this is the main integration point for query engines. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For additional commands, e-mail: issues-h...@iceberg.apache.org
