feat: add sort order to table metadata builder

src/iceberg/table_metadata.cc

@@ -21,9 +21,12 @@
 
 #include <algorithm>
 #include <chrono>
+#include <cstdint>
 #include <format>
+#include <optional>
 #include <ranges>
 #include <string>
+#include <unordered_map>
 
 #include <nlohmann/json.hpp>
 
@@ -39,12 +42,11 @@
 #include "iceberg/util/gzip_internal.h"
 #include "iceberg/util/macros.h"
 #include "iceberg/util/uuid.h"
-
 namespace iceberg {
-
 namespace {
 const TimePointMs kInvalidLastUpdatedMs = TimePointMs::min();
-}
+constexpr int32_t kLastAdded = -1;
+}  // namespace
 
 std::string ToString(const SnapshotLogEntry& entry) {
   return std::format("SnapshotLogEntry[timestampMillis={},snapshotId={}]",
@@ -274,11 +276,19 @@ struct TableMetadataBuilder::Impl {
 
   // Change tracking
   std::vector<std::unique_ptr<TableUpdate>> changes;
+  std::optional<int32_t> last_added_schema_id;
+  std::optional<int32_t> last_added_order_id;
+  std::optional<int32_t> last_added_spec_id;
 
   // Metadata location tracking
   std::optional<std::string> metadata_location;
   std::optional<std::string> previous_metadata_location;
 
+  // indexes for convenience
+  std::unordered_map<int32_t, std::shared_ptr<Schema>> schemas_by_id;
+  std::unordered_map<int32_t, std::shared_ptr<PartitionSpec>> specs_by_id;
+  std::unordered_map<int32_t, std::shared_ptr<SortOrder>> sort_orders_by_id;
+
   // Constructor for new table
   explicit Impl(int8_t format_version) : base(nullptr), metadata{} {
     metadata.format_version = format_version;
@@ -294,7 +304,22 @@ struct TableMetadataBuilder::Impl {
 
   // Constructor from existing metadata
   explicit Impl(const TableMetadata* base_metadata)
-      : base(base_metadata), metadata(*base_metadata) {}
+      : base(base_metadata), metadata(*base_metadata) {
+    // Initialize index maps from base metadata
+    for (const auto& schema : metadata.schemas) {
+      if (schema->schema_id().has_value()) {
+        schemas_by_id.emplace(schema->schema_id().value(), schema);
+      }
+    }
+
+    for (const auto& spec : metadata.partition_specs) {
+      specs_by_id.emplace(spec->spec_id(), spec);
+    }
+
+    for (const auto& order : metadata.sort_orders) {
+      sort_orders_by_id.emplace(order->order_id(), order);
+    }
+  }
 };
 
 TableMetadataBuilder::TableMetadataBuilder(int8_t format_version)
@@ -434,16 +459,95 @@ TableMetadataBuilder& TableMetadataBuilder::RemoveSchemas(
 
 TableMetadataBuilder& TableMetadataBuilder::SetDefaultSortOrder(
     std::shared_ptr<SortOrder> order) {
-  throw IcebergError(std::format("{} not implemented", __FUNCTION__));
+  BUILDER_ASSIGN_OR_RETURN(auto order_id, AddSortOrderInternal(*order));
+  return SetDefaultSortOrder(order_id);
 }
 
 TableMetadataBuilder& TableMetadataBuilder::SetDefaultSortOrder(int32_t order_id) {
-  throw IcebergError(std::format("{} not implemented", __FUNCTION__));
+  if (order_id == -1) {
+    if (!impl_->last_added_order_id.has_value()) {
+      return AddError(ErrorKind::kInvalidArgument,
+                      "Cannot set last added sort order: no sort order has been added");
+    }
+    return SetDefaultSortOrder(impl_->last_added_order_id.value());
+  }
+
+  if (order_id == impl_->metadata.default_sort_order_id) {
+    return *this;
+  }
+
+  impl_->metadata.default_sort_order_id = order_id;
+
+  if (impl_->last_added_order_id == std::make_optional(order_id)) {
+    impl_->changes.push_back(std::make_unique<table::SetDefaultSortOrder>(kLastAdded));
+  } else {
+    impl_->changes.push_back(std::make_unique<table::SetDefaultSortOrder>(order_id));
+  }
+  return *this;
+}
+
+Result<int32_t> TableMetadataBuilder::AddSortOrderInternal(const SortOrder& order) {
+  int32_t new_order_id = ReuseOrCreateNewSortOrderId(order);
+
+  if (impl_->sort_orders_by_id.find(new_order_id) != impl_->sort_orders_by_id.end()) {
+    // update last_added_order_id if the order was added in this set of changes (since it
+    // is now the last)
+    bool is_new_order =
+        impl_->last_added_order_id.has_value() &&
+        std::ranges::find_if(impl_->changes, [new_order_id](const auto& change) {
+          auto* add_sort_order = dynamic_cast<table::AddSortOrder*>(change.get());
+          return add_sort_order &&
+                 add_sort_order->sort_order()->order_id() == new_order_id;
+        }) != impl_->changes.cend();
+    impl_->last_added_order_id =
+        is_new_order ? std::make_optional(new_order_id) : std::nullopt;
+    return new_order_id;
+  }
+
+  // Get current schema and validate the sort order against it
+  ICEBERG_ASSIGN_OR_RAISE(auto schema, impl_->metadata.Schema());
+  ICEBERG_RETURN_UNEXPECTED(order.Validate(*schema));
+
+  std::shared_ptr<SortOrder> new_order;
+  if (order.is_unsorted()) {
+    new_order = SortOrder::Unsorted();
+  } else {
+    // Unlike freshSortOrder from Java impl, we don't use field name from old bound
+    // schema to rebuild the sort order.
+    ICEBERG_ASSIGN_OR_RAISE(
+        new_order,
+        SortOrder::Make(new_order_id, std::vector<SortField>(order.fields().begin(),
+                                                             order.fields().end())));
+  }
+
+  impl_->metadata.sort_orders.push_back(new_order);
+  impl_->sort_orders_by_id.emplace(new_order_id, new_order);
+
+  impl_->changes.push_back(std::make_unique<table::AddSortOrder>(new_order));
+  impl_->last_added_order_id = new_order_id;
+  return new_order_id;
 }
 
 TableMetadataBuilder& TableMetadataBuilder::AddSortOrder(
     std::shared_ptr<SortOrder> order) {
-  throw IcebergError(std::format("{} not implemented", __FUNCTION__));
+  BUILDER_ASSIGN_OR_RETURN(auto order_id, AddSortOrderInternal(*order));
+  return *this;
+}
+
+int32_t TableMetadataBuilder::ReuseOrCreateNewSortOrderId(const SortOrder& new_order) {
+  if (new_order.is_unsorted()) {
+    return SortOrder::kUnsortedOrderId;
+  }
+  // determine the next order id
+  int32_t new_order_id = SortOrder::kInitialSortOrderId;
+  for (const auto& order : impl_->metadata.sort_orders) {
+    if (order->SameOrder(new_order)) {
+      return order->order_id();
+    } else if (new_order_id <= order->order_id()) {
+      new_order_id = order->order_id() + 1;
+    }
+  }
+  return new_order_id;
 }
 
 TableMetadataBuilder& TableMetadataBuilder::AddSnapshot(

src/iceberg/table_metadata.h

@@ -436,6 +436,17 @@ class ICEBERG_EXPORT TableMetadataBuilder : public ErrorCollector {
   /// \brief Private constructor for building from existing metadata
   explicit TableMetadataBuilder(const TableMetadata* base);
 
+  /// \brief Internal method to add a sort order and return its ID
+  /// \param order The sort order to add
+  /// \return The ID of the added or reused sort order
+  Result<int32_t> AddSortOrderInternal(const SortOrder& order);
+
+  /// \brief Internal method to check for existing sort order and reuse its ID or create a
+  /// new one
+  /// \param new_order The sort order to check
+  /// \return The ID to use for this sort order (reused if exists, new otherwise)
+  int32_t ReuseOrCreateNewSortOrderId(const SortOrder& new_order);
+
   /// Internal state members
   struct Impl;
   std::unique_ptr<Impl> impl_;