Add a template for ParquetBlockInputStream

dbms/src/DataStreams/FormatFactory.cpp

@@ -29,6 +29,7 @@
 #include <DataStreams/MaterializingBlockOutputStream.h>
 #include <DataStreams/FormatFactory.h>
 #include <DataStreams/SquashingBlockOutputStream.h>
+#include <DataStreams/ParquetBlockInputStream.h>
 #include <DataTypes/FormatSettingsJSON.h>
 #if USE_CAPNP
 #include <DataStreams/CapnProtoRowInputStream.h>
@@ -88,6 +89,10 @@ BlockInputStreamPtr FormatFactory::getInput(const String & name, ReadBuffer & bu
 
         return wrap_row_stream(std::make_shared<CSVRowInputStream>(buf, sample, csv_delimiter, with_names));
     }
+    else if (name == "Parquet")
+    {
+        return std::make_shared<ParquetBlockInputStream>(buf, sample);
+    }
     else if (name == "TSKV")
     {
         return wrap_row_stream(std::make_shared<TSKVRowInputStream>(buf, sample, settings.input_format_skip_unknown_fields));

dbms/src/DataStreams/ParquetBlockInputStream.cpp

@@ -0,0 +1,38 @@
+#include <DataStreams/ParquetBlockInputStream.h>
+
+#include <IO/copyData.h>
+#include <IO/WriteBufferFromString.h>
+
+namespace DB
+{
+
+ParquetBlockInputStream::ParquetBlockInputStream(ReadBuffer & istr_, const Block & header_)
+    : istr(istr_)
+    , header(header_)
+{
+}
+
+Block ParquetBlockInputStream::getHeader() const
+{
+    return header;
+}
+
+Block ParquetBlockInputStream::readImpl()
+{
+    Block res;
+
+    if (istr.eof())
+        return res;
+
+    // TODO: maybe use parquet::RandomAccessSource?
+    std::string file_data;
+
+    {
+        WriteBufferFromString file_buffer(file_data);
+        copyData(istr, file_buffer);
+    }
+
+    return res;
+}
+
+}

dbms/src/DataStreams/ParquetBlockInputStream.h

@@ -0,0 +1,26 @@
+#pragma once
+
+#include <DataStreams/IProfilingBlockInputStream.h>
+/* #include <DataStreams/MarkInCompressedFile.h> */
+/* #include <Common/PODArray.h> */
+
+namespace DB
+{
+
+class ParquetBlockInputStream : public IProfilingBlockInputStream
+{
+public:
+    ParquetBlockInputStream(ReadBuffer & istr_, const Block & header_);
+
+    String getName() const override { return "Parquet"; }
+    Block getHeader() const override;
+
+protected:
+    Block readImpl() override;
+
+private:
+    ReadBuffer & istr;
+    Block header;
+};
+
+}