ClickHouse/dbms/src/DataStreams/InputStreamFromASTInsertQuery.cpp

#include <IO/ReadBufferFromMemory.h>
#include <DataStreams/InputStreamFromASTInsertQuery.h>


namespace DB
{

InputStreamFromASTInsertQuery::InputStreamFromASTInsertQuery(
    const ASTPtr & ast, ReadBuffer & input_buffer_tail_part, const BlockIO & streams, Context & context)
{
    const ASTInsertQuery * ast_insert_query = dynamic_cast<const ASTInsertQuery *>(ast.get());

    if (!ast_insert_query)
        throw Exception("Logical error: query requires data to insert, but it is not INSERT query", ErrorCodes::LOGICAL_ERROR);

    String format = ast_insert_query->format;
    if (format.empty())
        format = "Values";

    /// Data could be in parsed (ast_insert_query.data) and in not parsed yet (input_buffer_tail_part) part of query.

    input_buffer_ast_part = std::make_unique<ReadBufferFromMemory>(
        ast_insert_query->data, ast_insert_query->data ? ast_insert_query->end - ast_insert_query->data : 0);

    ConcatReadBuffer::ReadBuffers buffers;
    if (ast_insert_query->data)
        buffers.push_back(input_buffer_ast_part.get());
    buffers.push_back(&input_buffer_tail_part);

    /** NOTE Must not read from 'input_buffer_tail_part' before read all between 'ast_insert_query.data' and 'ast_insert_query.end'.
        * - because 'query.data' could refer to memory piece, used as buffer for 'input_buffer_tail_part'.
        */

    input_buffer_contacenated = std::make_unique<ConcatReadBuffer>(buffers);

    res_stream = context.getInputFormat(format, *input_buffer_contacenated, streams.out_sample, context.getSettings().max_insert_block_size);
}

}