Add fromBytes and fromFile static "make" methods to arrow.io.ipc.RecordBatchStreamReader MATLAB class.

Author: kevingurney

matlab/src/cpp/arrow/matlab/io/ipc/proxy/record_batch_stream_reader.cc

@@ -15,8 +15,10 @@
 // specific language governing permissions and limitations
 // under the License.
 
+#include "arrow/matlab/buffer/matlab_buffer.h"
 #include "arrow/matlab/io/ipc/proxy/record_batch_stream_reader.h"
 #include "arrow/io/file.h"
+#include "arrow/io/memory.h"
 #include "arrow/matlab/error/error.h"
 #include "arrow/matlab/tabular/proxy/record_batch.h"
 #include "arrow/matlab/tabular/proxy/schema.h"
@@ -36,6 +38,35 @@ RecordBatchStreamReader::RecordBatchStreamReader(
   REGISTER_METHOD(RecordBatchStreamReader, readTable);
 }
 
+libmexclass::proxy::MakeResult RecordBatchStreamReader::fromFile(const libmexclass::proxy::FunctionArguments& constructor_arguments) {
+        const mda::StructArray opts = constructor_arguments[0];
+	const mda::StringArray filename_mda = opts[0]["Filename"];
+	const auto filename_utf16 = std::u16string(filename_mda[0]);
+	MATLAB_ASSIGN_OR_ERROR(const auto filename_utf8,
+			arrow::util::UTF16StringToUTF8(filename_utf16),
+			error::UNICODE_CONVERSION_ERROR_ID);
+
+	MATLAB_ASSIGN_OR_ERROR(auto input_stream, arrow::io::ReadableFile::Open(filename_utf8),
+			error::FAILED_TO_OPEN_FILE_FOR_READ);
+
+	MATLAB_ASSIGN_OR_ERROR(auto reader,
+			arrow::ipc::RecordBatchStreamReader::Open(input_stream),
+			error::IPC_RECORD_BATCH_READER_OPEN_FAILED);
+
+	return std::make_shared<RecordBatchStreamReaderProxy>(std::move(reader));
+}
+
+libmexclass::proxy::MakeResult RecordBatchStreamReader::fromBytes(const libmexclass::proxy::FunctionArguments& constructor_arguments) {
+        const mda::StructArray opts = constructor_arguments[0];
+	const ::matlab::data::TypedArray<uint8_t> bytes_mda = opts[0]["Bytes"];
+	const auto matlab_buffer = std::make_shared<matlab::arrow::MatlabBuffer>(bytes_mda);
+	auto buffer_reader = std::make_shared<arrow::io::memory::BufferReader>(matlab_buffer);
+	MATLAB_ASSIGN_OR_ERROR(auto reader,
+			arrow::ipc::RecordBatchStreamReader::Open(buffer_reader),
+			error::IPC_RECORD_BATCH_READER_OPEN_FAILED);
+	return std::make_shared<RecordBatchStreamReaderProxy>(std::move(reader));
+}
+
 libmexclass::proxy::MakeResult RecordBatchStreamReader::make(
     const libmexclass::proxy::FunctionArguments& constructor_arguments) {
   namespace mda = ::matlab::data;
@@ -44,20 +75,18 @@ libmexclass::proxy::MakeResult RecordBatchStreamReader::make(
 
   const mda::StructArray opts = constructor_arguments[0];
 
-  const mda::StringArray filename_mda = opts[0]["Filename"];
-  const auto filename_utf16 = std::u16string(filename_mda[0]);
-  MATLAB_ASSIGN_OR_ERROR(const auto filename_utf8,
-                         arrow::util::UTF16StringToUTF8(filename_utf16),
-                         error::UNICODE_CONVERSION_ERROR_ID);
-
-  MATLAB_ASSIGN_OR_ERROR(auto input_stream, arrow::io::ReadableFile::Open(filename_utf8),
-                         error::FAILED_TO_OPEN_FILE_FOR_READ);
-
-  MATLAB_ASSIGN_OR_ERROR(auto reader,
-                         arrow::ipc::RecordBatchStreamReader::Open(input_stream),
-                         error::IPC_RECORD_BATCH_READER_OPEN_FAILED);
-
-  return std::make_shared<RecordBatchStreamReaderProxy>(std::move(reader));
+  // Dispatch to the appropriate static "make" method depending
+  // on the input type.
+  const mda::StringArray type_mda = opts[0]["Type"];
+  const auto type_utf16 = std::u16string(type_mda[0]);
+  if (type_utf16.equals(u"Bytes")) {
+	  return RecordBatchStreamReader::fromBytes(constructor_arguments);
+  } else if (type_utf16.equals(u"Filename")) {
+	  return RecordBatchStreamReader::fromFile(constructor_arguments);
+  } else {
+	  // TODO: Create static error id string
+	  return libmexclass::error::Error{"arrow:some:test:id", "Invalid construction type for RecordBatchStreamReader."};
+  }
 }
 
 void RecordBatchStreamReader::getSchema(libmexclass::proxy::method::Context& context) {

matlab/src/cpp/arrow/matlab/io/ipc/proxy/record_batch_stream_reader.h

@@ -30,6 +30,10 @@ class RecordBatchStreamReader : public libmexclass::proxy::Proxy {
 
   static libmexclass::proxy::MakeResult make(
       const libmexclass::proxy::FunctionArguments& constructor_arguments);
+  static libmexclass::proxy::MakeResult fromFile(
+      const libmexclass::proxy::FunctionArguments& constructor_arguments);
+  static libmexclass::proxy::MakeResult fromBytes(
+      const libmexclass::proxy::FunctionArguments& constructor_arguments);
 
  protected:
   std::shared_ptr<arrow::ipc::RecordBatchStreamReader> reader;

matlab/src/matlab/+arrow/+io/+ipc/RecordBatchStreamReader.m

@@ -26,14 +26,26 @@
         Schema
     end
 
+    methods (Static)
+	    function obj = fromBytes(bytes)
+                args = struct(Bytes=bytes, Type="Bytes");
+                proxyName = "arrow.io.ipc.proxy.RecordBatchStreamReader";
+                obj.Proxy = arrow.internal.proxy.create(proxyName, args);
+	    end
+
+	    function obj = fromFile(filename)
+                args = struct(Filename=filename, Type="File");
+                proxyName = "arrow.io.ipc.proxy.RecordBatchStreamReader";
+                obj.Proxy = arrow.internal.proxy.create(proxyName, args);
+	    end
+    end
+
     methods
-        function obj = RecordBatchStreamReader(filename)
+        function obj = RecordBatchStreamReader(proxy)
             arguments
-                filename(1, 1) string {mustBeNonzeroLengthText}
+                proxy(1, 1) libmexclass.proxy.Proxy
             end
-            args = struct(Filename=filename);
-            proxyName = "arrow.io.ipc.proxy.RecordBatchStreamReader";
-            obj.Proxy = arrow.internal.proxy.create(proxyName, args);
+            obj.Proxy = proxy;
         end
 
         function schema = get.Schema(obj)