From 95cd8762176663b1971f24bc69e4cb28f936c99f Mon Sep 17 00:00:00 2001
From: John Kerl <kerl.john.r@gmail.com>
Date: Mon, 19 Aug 2024 11:13:37 -0400
Subject: [PATCH] [c++] Methodize timestamped-schema-evolution factory (#2909)

---
 libtiledbsoma/src/soma/soma_array.cc | 21 +++++++++++++--------
 libtiledbsoma/src/soma/soma_array.h  |  7 +++++++
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/libtiledbsoma/src/soma/soma_array.cc b/libtiledbsoma/src/soma/soma_array.cc
index ccda688494..32d415aa38 100644
--- a/libtiledbsoma/src/soma/soma_array.cc
+++ b/libtiledbsoma/src/soma/soma_array.cc
@@ -471,6 +471,18 @@ uint64_t SOMAArray::_get_max_capacity(tiledb_datatype_t index_type) {
     }
 }
 
+ArraySchemaEvolution SOMAArray::_make_se() {
+    ArraySchemaEvolution se(*ctx_->tiledb_ctx());
+    if (timestamp_.has_value()) {
+        // ArraySchemaEvolution requires us to pair (t2, t2) even if our range
+        // is (t1, t2).
+        auto v = timestamp_.value();
+        TimestampRange tr(v.second, v.second);
+        se.set_timestamp_range(tr);
+    }
+    return se;
+}
+
 void SOMAArray::set_column_data(
     std::string_view name,
     uint64_t num_elems,
@@ -738,14 +750,7 @@ ArrowTable SOMAArray::_cast_table(
 
     // Go through all columns in the ArrowTable and cast the values to what is
     // in the ArraySchema on disk
-    ArraySchemaEvolution se(*ctx_->tiledb_ctx());
-    if (timestamp_.has_value()) {
-        // ArraySchemaEvolution requires us to pair (t2, t2) even if our range
-        // is (t1, t2).
-        auto v = timestamp_.value();
-        TimestampRange tr(v.second, v.second);
-        se.set_timestamp_range(tr);
-    }
+    ArraySchemaEvolution se = _make_se();
     bool evolve_schema = false;
     for (auto i = 0; i < arrow_schema->n_children; ++i) {
         auto orig_arrow_sch_ = arrow_schema->children[i];
diff --git a/libtiledbsoma/src/soma/soma_array.h b/libtiledbsoma/src/soma/soma_array.h
index d3a57987f2..a4bdffa9d3 100644
--- a/libtiledbsoma/src/soma/soma_array.h
+++ b/libtiledbsoma/src/soma/soma_array.h
@@ -762,6 +762,13 @@ class SOMAArray : public SOMAObject {
 
     uint64_t _get_max_capacity(tiledb_datatype_t index_type);
 
+    /**
+     * Convenience function for creating an ArraySchemaEvolution object
+     * referencing this array's context pointer, along with its open-at
+     * timestamp (if any).
+     */
+    ArraySchemaEvolution _make_se();
+
     bool _extend_enumeration(
         ArrowSchema* value_schema,
         ArrowArray* value_array,