ClickHouse/programs/disks/CommandWrite.cpp

#include <Interpreters/Context.h>
#include "ICommand.h"

#include <IO/ReadBufferFromEmptyFile.h>
#include <IO/ReadBufferFromFile.h>
#include <IO/WriteBufferFromFile.h>
#include <IO/copyData.h>
#include <Common/TerminalSize.h>

namespace DB
{

class CommandWrite final : public ICommand
{
public:
    CommandWrite()
    {
        command_name = "write";
        description = "Write a file from `path-from` to `path-to`";
        options_description.add_options()("path-from", po::value<String>(), "file from which we are reading, defaults to `stdin` (input from `stdin` is finished by Ctrl+D)")(
            "path-to", po::value<String>(), "file to which we are writing (mandatory, positional)");
        positional_options_description.add("path-to", 1);
    }


    void executeImpl(const CommandLineOptions & options, DisksClient & client) override
    {
        auto disk = client.getCurrentDiskWithPath();

        std::optional<String> path_from = getValueFromCommandLineOptionsWithOptional<String>(options, "path-from");

        String path_to = disk.getRelativeFromRoot(getValueFromCommandLineOptionsThrow<String>(options, "path-to"));

        auto in = [&]() -> std::unique_ptr<ReadBufferFromFileBase>
        {
            if (!path_from.has_value())
                return std::make_unique<ReadBufferFromFileDescriptor>(STDIN_FILENO);

            String relative_path_from = disk.getRelativeFromRoot(path_from.value());
            auto res = disk.getDisk()->readFileIfExists(relative_path_from, getReadSettings());
            if (res)
                return res;
            /// For backward compatibility.
            return std::make_unique<ReadBufferFromEmptyFile>();
        }();

        auto out = disk.getDisk()->writeFile(path_to);
        copyData(*in, *out);
        out->finalize();
    }
};

CommandPtr makeCommandWrite()
{
    return std::make_shared<DB::CommandWrite>();
}

}