Improve reading with use_stream = TRUE

DESCRIPTION

@@ -107,7 +107,7 @@ Suggests:
     tidyselect (>= 1.0.0),
     tmap (>= 2.0),
     vctrs,
-    wk
+    wk (>= 0.9.0)
 LinkingTo: 
     Rcpp
 VignetteBuilder: 

R/read.R

@@ -218,44 +218,49 @@ default_st_read_use_stream = function() {
 	)
 }
 
-process_cpl_read_ogr_stream = function(x, default_crs, num_features, fid_column_name,
-                                       crs = NULL, ...) {
-    is_geometry_column = vapply(
+process_cpl_read_ogr_stream = function(x, geom_column_info, num_features, fid_column_name,
+                                       crs = NULL, promote_to_multi = TRUE, ...) {
+	is_geometry_column = vapply(
 		x$get_schema()$children,
 		function(s) identical(s$metadata[["ARROW:extension:name"]], "ogc.wkb"),
 		logical(1)
 	)
-
-    crs = if (is.null(crs)) st_crs(default_crs) else st_crs(crs)
-	if (num_features == -1) {
+
+    geom_column_info$index = which(is_geometry_column)
+
+    if (num_features == -1) {
 		num_features = NULL
 	}
+
+    # Suppress warnings about extension type conversion (since we want the
+    # default behaviour of converting the storage type)
 	df = suppressWarnings(nanoarrow::convert_array_stream(x, size = num_features))
-
-	df[is_geometry_column] = lapply(df[is_geometry_column], function(x) {
-		class(x) <- "WKB"
-		x <- st_as_sfc(x)
-		st_set_crs(x, crs)	
-	})
-
-#	# Prefer "geometry" as the geometry column name
-#	if (any(is_geometry_column) && !("geometry" %in% names(df))) {
-#		names(df)[which(is_geometry_column)[1]] = "geometry"
-#	}
+
+	for (i in seq_len(nrow(geom_column_info))) {
+		crs = if (is.null(crs)) st_crs(geom_column_info$crs[[i]]) else st_crs(crs)
+		name = geom_column_info$name[[i]]
+		index = geom_column_info$index[[i]]
+
+		column_wkb = df[[index]]
+		attributes(column_wkb) = NULL
+		column_sfc = wk::wk_handle(
+			wk::new_wk_wkb(column_wkb),
+			wk::sfc_writer(promote_multi = promote_to_multi)
+		)
+
+		df[[index]] = st_set_crs(column_sfc, crs)
+		names(df)[index] = name
+	}
 
 	# Rename OGC_FID to fid_column_name and move to end
 	if (length(fid_column_name) == 1 && "OGC_FID" %in% names(df)) {
-		df <- df[c(setdiff(names(df), "OGC_FID"), "OGC_FID")]
+		df = df[c(setdiff(names(df), "OGC_FID"), "OGC_FID")]
 		names(df)[names(df) == "OGC_FID"] = fid_column_name
 	}
 
-	# Move geometry to the end
-#	if ("geometry" %in% names(df)) {
-#		df <- df[c(setdiff(names(df), "geometry"), "geometry")]
-#	}
-	gc1 = which(is_geometry_column)[1]
-	df = df[c(setdiff(seq_along(df), gc1), gc1)]
-
+	# All geometry columns to the end
+	df = df[c(setdiff(seq_along(df), geom_column_info$index), geom_column_info$index)]
+
 	process_cpl_read_ogr(df, ...)
 }
 
@@ -296,8 +301,10 @@ st_read.character = function(dsn, layer, ..., query = NA, options = NULL, quiet
 		stream = nanoarrow::nanoarrow_allocate_array_stream()
 		info = CPL_read_gdal_stream(stream, dsn, layer, query, as.character(options), quiet,
 		    drivers, wkt_filter, dsn_exists, dsn_isdb, fid_column_name, getOption("width"))
-		process_cpl_read_ogr_stream(stream, default_crs = info[[1]], num_features = info[[2]],
-			fid_column_name = fid_column_name, stringsAsFactors = stringsAsFactors, quiet = quiet, ...)
+		geom_column_info = data.frame(name = info[[1]], crs = info[[2]], stringsAsFactors = FALSE)
+		process_cpl_read_ogr_stream(stream, geom_column_info, num_features = info[[3]],
+			fid_column_name = fid_column_name, stringsAsFactors = stringsAsFactors, quiet = quiet,
+			promote_to_multi = promote_to_multi, ...)
 	} else {
 		x = CPL_read_ogr(dsn, layer, query, as.character(options), quiet, type, fid_column_name,
 		    drivers, wkt_filter, promote_to_multi, int64_as_string, dsn_exists, dsn_isdb, getOption("width"))

src/gdal_read_stream.cpp

@@ -97,14 +97,32 @@ Rcpp::List CPL_read_gdal_stream(
     auto stream_out = reinterpret_cast<struct ArrowArrayStream*>(
         R_ExternalPtrAddr(stream_xptr));
 
-    OGRSpatialReference* crs = poLayer->GetSpatialRef();
-
-    Rcpp::String wkt_str = NA_STRING;
-    if (crs != nullptr) {
-        char* wkt_out;
-        crs->exportToWkt(&wkt_out);
-        wkt_str = wkt_out;
-        CPLFree(wkt_out);
+    OGRFeatureDefn* poFDefn = poLayer->GetLayerDefn();
+    Rcpp::CharacterVector geom_field_name(poFDefn->GetGeomFieldCount());
+    Rcpp::CharacterVector geom_field_crs(poFDefn->GetGeomFieldCount());
+
+    for (int i = 0; i < poFDefn->GetGeomFieldCount(); i++) {
+        OGRGeomFieldDefn* poGFDefn = poFDefn->GetGeomFieldDefn(i);
+		if (poGFDefn == nullptr) {
+			Rcpp::stop("GeomFieldDefn error"); // #nocov
+        }
+
+        const char* name = poGFDefn->GetNameRef();
+        if (strlen(name) == 0) {
+            name = "geometry";
+        }
+
+        const OGRSpatialReference* crs = poGFDefn->GetSpatialRef();
+        Rcpp::String wkt_str = NA_STRING;
+        if (crs != nullptr) {
+            char* wkt_out;
+            crs->exportToWkt(&wkt_out);
+            wkt_str = wkt_out;
+            CPLFree(wkt_out);
+        }
+
+        geom_field_name[i] = name;
+        geom_field_crs[i] = wkt_str;
     }
 
     struct ArrowArrayStream stream_temp;
@@ -122,7 +140,10 @@ Rcpp::List CPL_read_gdal_stream(
         num_features = -1;
     }
 
-    return Rcpp::List::create(wkt_str, Rcpp::NumericVector::create(num_features));
+    return Rcpp::List::create(
+        geom_field_name,
+        geom_field_crs,
+        Rcpp::NumericVector::create(num_features));
 
 #else