feat(inspect): Add base class for metadata table support

src/iceberg/CMakeLists.txt

@@ -41,6 +41,9 @@ set(ICEBERG_SOURCES
     file_io_registry.cc
     file_reader.cc
     file_writer.cc
+    inspect/history_table.cc
+    inspect/metadata_table.cc
+    inspect/snapshots_table.cc
     inheritable_metadata.cc
     json_serde.cc
     location_provider.cc

src/iceberg/inspect/CMakeLists.txt

@@ -0,0 +1,18 @@
+# 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.
+
+iceberg_install_all_headers(iceberg/inspect)

src/iceberg/inspect/history_table.cc

@@ -0,0 +1,56 @@
+/*
+ * 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.
+ */
+
+#include "iceberg/inspect/history_table.h"
+
+#include <memory>
+#include <utility>
+
+#include "iceberg/inspect/metadata_table.h"
+#include "iceberg/schema.h"
+#include "iceberg/schema_field.h"
+#include "iceberg/table_identifier.h"
+#include "iceberg/type.h"
+
+namespace iceberg {
+
+HistoryTable::HistoryTable(std::shared_ptr<Table> table)
+    : MetadataTable(table, CreateName(table->name())) {}
+
+HistoryTable::~HistoryTable() = default;
+
+std::shared_ptr<Schema> HistoryTable::GetSchema() const {
+  return std::make_shared<Schema>(
+      std::vector<SchemaField>{
+          SchemaField::MakeRequired(1, "made_current_at", timestamp_tz()),
+          SchemaField::MakeRequired(2, "snapshot_id", int64()),
+          SchemaField::MakeOptional(3, "parent_id", int64()),
+          SchemaField::MakeRequired(4, "is_current_ancestor", boolean())},
+      1);
+}
+
+TableIdentifier HistoryTable::CreateName(const TableIdentifier& source_name) {
+  return TableIdentifier{source_name.ns, source_name.name + ".history"};
+}
+
+Result<std::unique_ptr<HistoryTable>> HistoryTable::Make(std::shared_ptr<Table> table) {
+  return std::unique_ptr<HistoryTable>(new HistoryTable(table));
+}
+
+}  // namespace iceberg

src/iceberg/inspect/history_table.h

@@ -0,0 +1,59 @@
+/*
+ * 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 <memory>
+
+#include "iceberg/iceberg_export.h"
+#include "iceberg/inspect/metadata_table.h"
+#include "iceberg/result.h"
+#include "iceberg/table.h"
+
+namespace iceberg {
+
+/// \brief History metadata table
+///
+/// History is based on the table's snapshot log, which logs each update
+/// to the table's current snapshot. Each row has columns:
+/// - made_current_at (long, timestamp)
+/// - snapshot_id (long)
+/// - parent_id (long, optional)
+/// - is_current_ancestor (bool)
+class ICEBERG_EXPORT HistoryTable : public MetadataTable {
+ public:
+  /// \brief Create a HistoryTable from table metadata
+  ///
+  /// \param[in] table The source table
+  /// \return A HistoryTable instance or error status
+  static Result<std::unique_ptr<HistoryTable>> Make(std::shared_ptr<Table> table);
+
+  ~HistoryTable() override;
+
+  MetadataTableType type() const noexcept override { return MetadataTableType::kHistory; }
+
+  std::shared_ptr<Schema> GetSchema() const override;
+
+ private:
+  explicit HistoryTable(std::shared_ptr<Table> table);
+
+  TableIdentifier CreateName(const TableIdentifier& source_name);
+};
+
+}  // namespace iceberg

src/iceberg/inspect/meson.build

@@ -0,0 +1,25 @@
+# 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.
+
+install_headers(
+    [
+        'history_table.h',
+        'metadata_table.h',
+        'snapshots_table.h',
+    ],
+    subdir: 'iceberg/inspect',
+)

src/iceberg/inspect/metadata_table.cc

@@ -0,0 +1,95 @@
+/*
+ * 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.
+ */
+
+#include "iceberg/inspect/metadata_table.h"
+
+#include <memory>
+#include <string>
+#include <utility>
+
+#include "iceberg/file_io.h"
+#include "iceberg/inspect/history_table.h"
+#include "iceberg/inspect/snapshots_table.h"
+#include "iceberg/partition_spec.h"
+#include "iceberg/schema.h"
+#include "iceberg/schema_field.h"
+#include "iceberg/sort_order.h"
+#include "iceberg/table_identifier.h"
+#include "iceberg/table_metadata.h"
+#include "iceberg/table_properties.h"
+#include "iceberg/table_scan.h"
+#include "iceberg/type.h"
+#include "iceberg/type_fwd.h"
+#include "iceberg/util/uuid.h"
+
+namespace iceberg {
+
+MetadataTable::MetadataTable(std::shared_ptr<Table> source_table,
+                             TableIdentifier identifier)
+    : StaticTable(identifier, source_table->metadata(),
+                  std::string(source_table->metadata_file_location()), source_table->io(),
+                  source_table->catalog()),
+      source_table_(std::move(source_table)) {
+  auto schema = GetSchema();
+  if (!schema) {
+    schema = std::make_shared<Schema>(std::vector<SchemaField>{}, 1);
+  }
+
+  auto builder =
+      TableMetadataBuilder::BuildFromEmpty(TableMetadata::kDefaultTableFormatVersion);
+  auto result = builder->AssignUUID(Uuid::GenerateV4().ToString())
+                    .SetLocation(std::string(source_table_->location()))
+                    .SetCurrentSchema(schema, schema->schema_id())
+                    .SetDefaultSortOrder(SortOrder::Unsorted())
+                    .SetDefaultPartitionSpec(PartitionSpec::Unpartitioned())
+                    .SetProperties({})
+                    .Build();
+
+  if (!result.has_value()) {
+    // If metadata building fails, keep the original metadata from source_table
+    return;
+  }
+
+  std::shared_ptr<TableMetadata> built_metadata = std::move(result.value());
+
+  metadata_ = built_metadata;
+  metadata_cache_ = std::make_unique<TableMetadataCache>(metadata_.get());
+}
+
+MetadataTable::~MetadataTable() = default;
+
+Status MetadataTable::Refresh() { return source_table_->Refresh(); }
+
+Result<std::unique_ptr<TableScanBuilder>> MetadataTable::NewScan() const {
+  return NotSupported("TODO: Scanning metadata tables is not yet supported");
+};
+
+Result<std::unique_ptr<MetadataTable>> MetadataTableFactory::CreateMetadataTable(
+    std::shared_ptr<Table> table, MetadataTableType type) {
+  switch (type) {
+    case MetadataTableType::kSnapshots:
+      return SnapshotsTable::Make(table);
+    case MetadataTableType::kHistory:
+      return HistoryTable::Make(table);
+  }
+
+  return Invalid("Unsupported metadata table type");
+}
+
+}  // namespace iceberg