From 6d2db6dbadfffe4ff09c2d8e4ce60941adc933fe Mon Sep 17 00:00:00 2001
From: John Kerl <kerl.john.r@gmail.com>
Date: Tue, 24 Sep 2024 21:11:37 -0400
Subject: [PATCH] [r] Push `ndim` down to C++

---
 apis/r/R/RcppExports.R     |  4 ++++
 apis/r/R/TileDBArray.R     |  3 +--
 apis/r/src/RcppExports.cpp | 13 +++++++++++++
 apis/r/src/rinterface.cpp  | 10 ++++++++++
 4 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/apis/r/R/RcppExports.R b/apis/r/R/RcppExports.R
index 8e1a938bf9..ad37c6402e 100644
--- a/apis/r/R/RcppExports.R
+++ b/apis/r/R/RcppExports.R
@@ -192,6 +192,10 @@ has_current_domain <- function(uri, ctxxp) {
     .Call(`_tiledbsoma_has_current_domain`, uri, ctxxp)
 }
 
+ndim <- function(uri, ctxxp) {
+    .Call(`_tiledbsoma_ndim`, uri, ctxxp)
+}
+
 resize <- function(uri, new_shape, ctxxp) {
     invisible(.Call(`_tiledbsoma_resize`, uri, new_shape, ctxxp))
 }
diff --git a/apis/r/R/TileDBArray.R b/apis/r/R/TileDBArray.R
index 64923c82b0..f974022b7a 100644
--- a/apis/r/R/TileDBArray.R
+++ b/apis/r/R/TileDBArray.R
@@ -248,8 +248,7 @@ TileDBArray <- R6::R6Class(
     #' @description Retrieve number of dimensions (lifecycle: maturing)
     #' @return A scalar with the number of dimensions
     ndim = function() {
-      dims <- tiledb::dimensions(self$tiledb_schema())
-      length(dims)
+      ndim(self$uri, private$.soma_context)
     },
 
     #' @description Retrieve the array attributes (lifecycle: maturing)
diff --git a/apis/r/src/RcppExports.cpp b/apis/r/src/RcppExports.cpp
index 7de387a80c..dceab26f3e 100644
--- a/apis/r/src/RcppExports.cpp
+++ b/apis/r/src/RcppExports.cpp
@@ -416,6 +416,18 @@ BEGIN_RCPP
     return rcpp_result_gen;
 END_RCPP
 }
+// ndim
+Rcpp::NumericVector ndim(const std::string& uri, Rcpp::XPtr<somactx_wrap_t> ctxxp);
+RcppExport SEXP _tiledbsoma_ndim(SEXP uriSEXP, SEXP ctxxpSEXP) {
+BEGIN_RCPP
+    Rcpp::RObject rcpp_result_gen;
+    Rcpp::RNGScope rcpp_rngScope_gen;
+    Rcpp::traits::input_parameter< const std::string& >::type uri(uriSEXP);
+    Rcpp::traits::input_parameter< Rcpp::XPtr<somactx_wrap_t> >::type ctxxp(ctxxpSEXP);
+    rcpp_result_gen = Rcpp::wrap(ndim(uri, ctxxp));
+    return rcpp_result_gen;
+END_RCPP
+}
 // resize
 void resize(const std::string& uri, Rcpp::NumericVector new_shape, Rcpp::XPtr<somactx_wrap_t> ctxxp);
 RcppExport SEXP _tiledbsoma_resize(SEXP uriSEXP, SEXP new_shapeSEXP, SEXP ctxxpSEXP) {
@@ -642,6 +654,7 @@ static const R_CallMethodDef CallEntries[] = {
     {"_tiledbsoma_maybe_soma_joinid_shape", (DL_FUNC) &_tiledbsoma_maybe_soma_joinid_shape, 2},
     {"_tiledbsoma_maybe_soma_joinid_maxshape", (DL_FUNC) &_tiledbsoma_maybe_soma_joinid_maxshape, 2},
     {"_tiledbsoma_has_current_domain", (DL_FUNC) &_tiledbsoma_has_current_domain, 2},
+    {"_tiledbsoma_ndim", (DL_FUNC) &_tiledbsoma_ndim, 2},
     {"_tiledbsoma_resize", (DL_FUNC) &_tiledbsoma_resize, 3},
     {"_tiledbsoma_tiledbsoma_upgrade_shape", (DL_FUNC) &_tiledbsoma_tiledbsoma_upgrade_shape, 3},
     {"_tiledbsoma_sr_setup", (DL_FUNC) &_tiledbsoma_sr_setup, 10},
diff --git a/apis/r/src/rinterface.cpp b/apis/r/src/rinterface.cpp
index ca34e14356..4123dd3775 100644
--- a/apis/r/src/rinterface.cpp
+++ b/apis/r/src/rinterface.cpp
@@ -285,6 +285,16 @@ Rcpp::LogicalVector has_current_domain(const std::string& uri, Rcpp::XPtr<somact
     return retval;
 }
 
+// [[Rcpp::export]]
+Rcpp::NumericVector ndim(
+    const std::string& uri, Rcpp::XPtr<somactx_wrap_t> ctxxp) {
+    auto sr = tdbs::SOMAArray::open(OpenMode::read, uri, ctxxp->ctxptr);
+    auto lib_retval = sr->ndim();
+    sr->close();
+
+    return Rcpp::NumericVector::create(lib_retval);
+}
+
 // [[Rcpp::export]]
 void resize(const std::string& uri,
             Rcpp::NumericVector new_shape,