Using Arrow in C++ and R

DESCRIPTION

Package: skytethr
Title: Integration to 'Skytether-singlecell'
Version: 0.1.0
LinkingTo: cpp11, boostfs, arrow
SystemRequirements: C++11

errors.md

Errors when headers are correct

/tmp/RtmpLvPZfE/file7ecb2abfb8d2/src/cpp11.cpp:4:1: error: ‘arrow’ does not name a type
 arrow::Result<BatchStreamRdrPtr> R_GetReaderForKey(cpp11::r_string table_key);
 ^~~~~
/tmp/RtmpLvPZfE/file7ecb2abfb8d2/src/cpp11.cpp: In function ‘SEXPREC* _skyteth_r_R_GetReaderForKey(SEXP)’:
/tmp/RtmpLvPZfE/file7ecb2abfb8d2/src/cpp11.cpp:7:27: error: ‘R_GetReaderForKey’ was not declared in this scope
     return cpp11::as_sexp(R_GetReaderForKey(cpp11::as_cpp<cpp11::decay_t<cpp11::r_string>>(table_key)));
                           ^~~~~~~~~~~~~~~~~
make: *** [/tmp/RtmpLvPZfE/file7ecb2abfb8d2/src/cpp11.o] Error 1
Error: Compilation failed.
Execution halted

Errors when headers are incorrect

/tmp/RtmpHXyYvK/file7eb21ed3dde0/src/skyteth_r.cpp:35:1: error: ‘arrow’ does not name a type
 arrow::Result<BatchStreamRdrPtr>
 ^~~~~
make: *** [/tmp/RtmpHXyYvK/file7eb21ed3dde0/src/skyteth_r.o] Error 1
Error: Compilation failed.
Execution halted

skyteth_r.no_headers.cpp

// ------------------------------
// Dependencies

#include "cpp11.hpp"


// ------------------------------
// Common API

[[cpp11::register]]
arrow::Result<BatchStreamRdrPtr>
R_GetReaderForKey(cpp11::r_string table_key) {
    arrow::Result<BatchStreamRdrPtr> reader_result;

    KineticConn kconn = KineticConn();
    kconn.Connect();

    if (kconn.IsConnected()) {
        reader_result = kconn.GetReaderForKey(static_cast<std::string>(table_key));
        kconn.Disconnect();
    }
    else {
        reader_result = arrow::Result<BatchStreamRdrPtr>(
            arrow::Status::Invalid("Could not connect to kinetic drive")
        );
    }

    return reader_result;
}

skyteth_r.r

library(arrow)
library(cpp11)

cpp_source(file='src/skyteth_r.cpp')

skyteth_r.with_headers.cpp

// ------------------------------
// Dependencies

#include "cpp11.hpp"

// These are included in the skytether headers, but copied here to be explicit
#include <arrow/api.h>
#include <arrow/io/api.h>
#include <arrow/ipc/api.h>
#include <arrow/filesystem/api.h>
#include <arrow/dataset/api.h>

#include <skytether/skytether.hpp>
#include <skytether/skytether_types.hpp>
#include <skytether/connectors/connectors.hpp>


/* Some things from the skytether headers for reference:

typedef std::vector<TablePtr>                                TableVector;
typedef std::shared_ptr<arrow::ipc::RecordBatchStreamReader> BatchStreamRdrPtr;

struct KineticConn {
    int conn_id;

    KineticConn();

    bool IsConnected();

    void Disconnect();
    void Connect();

    KBuffer*      GetKey(std::string key_name);
    arrow::Status PutTableBatches(std::string table_key, TablePtr table_data, int64_t batch_size);

    arrow::Result<BatchStreamRdrPtr>
    GetReaderForKey(std::string table_key);
};
*/

// ------------------------------
// Common API

[[cpp11::register]]
arrow::Result<BatchStreamRdrPtr>
R_GetReaderForKey(cpp11::r_string table_key) {
    arrow::Result<BatchStreamRdrPtr> reader_result;

    KineticConn kconn = KineticConn();
    kconn.Connect();

    if (kconn.IsConnected()) {
        reader_result = kconn.GetReaderForKey(static_cast<std::string>(table_key));
        kconn.Disconnect();
    }
    else {
        reader_result = arrow::Result<BatchStreamRdrPtr>(
            arrow::Status::Invalid("Could not connect to kinetic drive")
        );
    }

    return reader_result;
}