feat: add row delta update

Implements the RowDelta update builder, table and transaction factory methods, and focused tests for row-level add/delete flows.

Co-authored-by: Codex <codex@openai.com>

Author: manuzhang

src/iceberg/CMakeLists.txt

@@ -105,6 +105,7 @@ set(ICEBERG_SOURCES
     update/merge_append.cc
     update/merging_snapshot_update.cc
     update/pending_update.cc
+    update/row_delta.cc
     update/set_snapshot.cc
     update/snapshot_manager.cc
     update/snapshot_update.cc

src/iceberg/meson.build

@@ -130,6 +130,7 @@ iceberg_sources = files(
     'update/merge_append.cc',
     'update/merging_snapshot_update.cc',
     'update/pending_update.cc',
+    'update/row_delta.cc',
     'update/set_snapshot.cc',
     'update/snapshot_manager.cc',
     'update/snapshot_update.cc',

src/iceberg/table.cc

@@ -35,6 +35,7 @@
 #include "iceberg/update/expire_snapshots.h"
 #include "iceberg/update/fast_append.h"
 #include "iceberg/update/merge_append.h"
+#include "iceberg/update/row_delta.h"
 #include "iceberg/update/set_snapshot.h"
 #include "iceberg/update/snapshot_manager.h"
 #include "iceberg/update/update_location.h"
@@ -231,6 +232,12 @@ Result<std::shared_ptr<DeleteFiles>> Table::NewDeleteFiles() {
   return DeleteFiles::Make(name().name, std::move(ctx));
 }
 
+Result<std::shared_ptr<RowDelta>> Table::NewRowDelta() {
+  ICEBERG_ASSIGN_OR_RAISE(
+      auto ctx, TransactionContext::Make(shared_from_this(), TransactionKind::kUpdate));
+  return RowDelta::Make(name().name, std::move(ctx));
+}
+
 Result<std::shared_ptr<UpdateStatistics>> Table::NewUpdateStatistics() {
   ICEBERG_ASSIGN_OR_RAISE(
       auto ctx, TransactionContext::Make(shared_from_this(), TransactionKind::kUpdate));

src/iceberg/table.h

@@ -182,6 +182,9 @@ class ICEBERG_EXPORT Table : public std::enable_shared_from_this<Table> {
   /// \brief Create a new DeleteFiles to delete data files and commit the changes.
   virtual Result<std::shared_ptr<DeleteFiles>> NewDeleteFiles();
 
+  /// \brief Create a new RowDelta to add rows and row-level deletes.
+  virtual Result<std::shared_ptr<RowDelta>> NewRowDelta();
+
   /// \brief Create a new SnapshotManager to manage snapshots and snapshot references.
   virtual Result<std::shared_ptr<SnapshotManager>> NewSnapshotManager();
 

src/iceberg/test/CMakeLists.txt

@@ -229,6 +229,7 @@ if(ICEBERG_BUILD_BUNDLE)
                    merge_append_test.cc
                    merging_snapshot_update_test.cc
                    name_mapping_update_test.cc
+                   row_delta_test.cc
                    snapshot_manager_test.cc
                    transaction_test.cc
                    update_location_test.cc