ARROW-3760: [R] Support Arrow CSV reader

The main entry point is the `csv_read()` function, all it does is create a `csv::TableReader` with the `csv_table_reader()` generic and then `$Read()` from it.

as in the apache#2947 for feather format, `csv_table_reader` is generic with the methods:
 - arrow::io::InputStream: calls the TableReader actor with the other options
 - character and fs_path: depending on the `mmap` option (TRUE by default) it opens the file with `mmap_open()` of `file_open()` and then calls the other method.

``` r
library(arrow)
tf <- tempfile()
readr::write_csv(iris, tf)

tab1 <- csv_read(tf)
tab1
#> arrow::Table
as_tibble(tab1)
#> # A tibble: 150 x 5
#>    Sepal.Length Sepal.Width Petal.Length Petal.Width Species
#>           <dbl>       <dbl>        <dbl>       <dbl> <chr>
#>  1          5.1         3.5          1.4         0.2 setosa
#>  2          4.9         3            1.4         0.2 setosa
#>  3          4.7         3.2          1.3         0.2 setosa
#>  4          4.6         3.1          1.5         0.2 setosa
#>  5          5           3.6          1.4         0.2 setosa
#>  6          5.4         3.9          1.7         0.4 setosa
#>  7          4.6         3.4          1.4         0.3 setosa
#>  8          5           3.4          1.5         0.2 setosa
#>  9          4.4         2.9          1.4         0.2 setosa
#> 10          4.9         3.1          1.5         0.1 setosa
#> # … with 140 more rows
```

<sup>Created on 2018-11-13 by the [reprex package](https://reprex.tidyverse.org) (v0.2.1.9000)</sup>

Author: Romain Francois <romain@purrple.cat>

Closes apache#2949 from romainfrancois/ARROW-3760/csv_reader and squashes the following commits:

951e9f5 <Romain Francois> s/csv_read/read_csv_arrow/
7770ec5 <Romain Francois> not using readr:: at this point
bb13a76 <Romain Francois> rebase
83b5162 <Romain Francois> s/file_open/ReadableFile/
959020c <Romain Francois> No need to special use mmap for file path method
6e74003 <Romain Francois> going through CharacterVector makes sure this is a character vector
2585501 <Romain Francois> line breaks for readability
0ab8397 <Romain Francois> linting
09187e6 <Romain Francois> Expose arrow::csv::TableReader, functions csv_table_reader() + csv_read()

Author: romainfrancois

r/DESCRIPTION

@@ -55,6 +55,7 @@ Collate:
     'array.R'
     'buffer.R'
     'compute.R'
+    'csv.R'
     'dictionary.R'
     'feather.R'
     'io.R'

r/NAMESPACE

@@ -39,6 +39,11 @@ S3method(buffer,default)
 S3method(buffer,integer)
 S3method(buffer,numeric)
 S3method(buffer,raw)
+S3method(csv_table_reader,"arrow::csv::TableReader")
+S3method(csv_table_reader,"arrow::io::InputStream")
+S3method(csv_table_reader,character)
+S3method(csv_table_reader,default)
+S3method(csv_table_reader,fs_path)
 S3method(length,"arrow::Array")
 S3method(names,"arrow::RecordBatch")
 S3method(print,"arrow-enum")
@@ -92,6 +97,10 @@ export(boolean)
 export(buffer)
 export(cast_options)
 export(chunked_array)
+export(csv_convert_options)
+export(csv_parse_options)
+export(csv_read_options)
+export(csv_table_reader)
 export(date32)
 export(date64)
 export(decimal)
@@ -111,6 +120,7 @@ export(mmap_open)
 export(null)
 export(print.integer64)
 export(read_arrow)
+export(read_csv_arrow)
 export(read_feather)
 export(read_message)
 export(read_record_batch)
@@ -141,6 +151,7 @@ importFrom(glue,glue)
 importFrom(purrr,map)
 importFrom(purrr,map2)
 importFrom(purrr,map_int)
+importFrom(rlang,abort)
 importFrom(rlang,dots_n)
 importFrom(rlang,list2)
 importFrom(rlang,warn)

r/R/RcppExports.R

@@ -0,0 +1,182 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+#' @include R6.R
+
+`arrow::csv::TableReader` <- R6Class("arrow::csv::TableReader", inherit = `arrow::Object`,
+  public = list(
+    Read = function() shared_ptr(`arrow::Table`, csv___TableReader__Read(self))
+  )
+)
+
+`arrow::csv::ReadOptions` <- R6Class("arrow::csv::ReadOptions", inherit = `arrow::Object`)
+`arrow::csv::ParseOptions` <- R6Class("arrow::csv::ParseOptions", inherit = `arrow::Object`)
+`arrow::csv::ConvertOptions` <- R6Class("arrow::csv::ConvertOptions", inherit = `arrow::Object`)
+
+#' read options for the csv reader
+#'
+#' @param use_threads Whether to use the global CPU thread pool
+#' @param block_size Block size we request from the IO layer; also determines the size of chunks when use_threads is `TRUE`
+#'
+#' @export
+csv_read_options <- function(use_threads = TRUE, block_size = 1048576L) {
+  shared_ptr(`arrow::csv::ReadOptions`, csv___ReadOptions__initialize(
+    list(
+      use_threads = use_threads,
+      block_size = block_size
+    )
+  ))
+}
+
+#' Parsing options
+#'
+#' @param delimiter Field delimiter
+#' @param quoting Whether quoting is used
+#' @param quote_char Quoting character (if `quoting` is `TRUE`)
+#' @param double_quote Whether a quote inside a value is double-quoted
+#' @param escaping Whether escaping is used
+#' @param escape_char Escaping character (if `escaping` is `TRUE`)
+#' @param newlines_in_values Whether values are allowed to contain CR (`0x0d``) and LF (`0x0a``) characters
+#' @param ignore_empty_lines Whether empty lines are ignored.  If false, an empty line represents
+#' @param header_rows Number of header rows to skip (including the first row containing column names)
+#'
+#' @export
+csv_parse_options <- function(
+  delimiter = ",", quoting = TRUE, quote_char = '"',
+  double_quote = TRUE, escaping = FALSE, escape_char = '\\',
+  newlines_in_values = FALSE, ignore_empty_lines = TRUE,
+  header_rows = 1L
+){
+  shared_ptr(`arrow::csv::ParseOptions`, csv___ParseOptions__initialize(
+    list(
+      delimiter = delimiter,
+      quoting = quoting,
+      quote_char = quote_char,
+      double_quote = double_quote,
+      escaping = escaping,
+      escape_char = escape_char,
+      newlines_in_values = newlines_in_values,
+      ignore_empty_lines = ignore_empty_lines,
+      header_rows = header_rows
+    )
+  ))
+}
+
+#' Conversion Options for the csv reader
+#'
+#' @param check_utf8 Whether to check UTF8 validity of string columns
+#'
+#' @export
+csv_convert_options <- function(check_utf8 = TRUE){
+  shared_ptr(`arrow::csv::ConvertOptions`, csv___ConvertOptions__initialize(
+    list(
+      check_utf8 = check_utf8
+    )
+  ))
+}
+
+#' CSV table reader
+#'
+#' @param file file
+#' @param read_options, see [csv_read_options()]
+#' @param parse_options, see [csv_parse_options()]
+#' @param convert_options, see [csv_convert_options()]
+#' @param ... additional parameters.
+#'
+#' @export
+csv_table_reader <- function(file,
+  read_options = csv_read_options(),
+  parse_options = csv_parse_options(),
+  convert_options = csv_convert_options(),
+  ...
+){
+  UseMethod("csv_table_reader")
+}
+
+#' @importFrom rlang abort
+#' @export
+csv_table_reader.default <- function(file,
+  read_options = csv_read_options(),
+  parse_options = csv_parse_options(),
+  convert_options = csv_convert_options(),
+  ...
+) {
+  abort("unsupported")
+}
+
+#' @export
+`csv_table_reader.character` <- function(file,
+  read_options = csv_read_options(),
+  parse_options = csv_parse_options(),
+  convert_options = csv_convert_options(),
+  ...
+){
+  csv_table_reader(fs::path_abs(file),
+    read_options = read_options,
+    parse_options = parse_options,
+    convert_options = convert_options,
+    ...
+  )
+}
+
+#' @export
+`csv_table_reader.fs_path` <- function(file,
+  read_options = csv_read_options(),
+  parse_options = csv_parse_options(),
+  convert_options = csv_convert_options(),
+  ...
+){
+  csv_table_reader(ReadableFile(file),
+    read_options = read_options,
+    parse_options = parse_options,
+    convert_options = convert_options,
+    ...
+  )
+}
+
+#' @export
+`csv_table_reader.arrow::io::InputStream` <- function(file,
+  read_options = csv_read_options(),
+  parse_options = csv_parse_options(),
+  convert_options = csv_convert_options(),
+  ...
+){
+  shared_ptr(`arrow::csv::TableReader`,
+    csv___TableReader__Make(file, read_options, parse_options, convert_options)
+  )
+}
+
+#' @export
+`csv_table_reader.arrow::csv::TableReader` <- function(file,
+  read_options = csv_read_options(),
+  parse_options = csv_parse_options(),
+  convert_options = csv_convert_options(),
+  ...
+){
+  file
+}
+
+#' Read csv file into an arrow::Table
+#'
+#' Use arrow::csv::TableReader from [csv_table_reader()]
+#'
+#' @param ... Used to construct an arrow::csv::TableReader
+#' @export
+read_csv_arrow <- function(...) {
+  csv_table_reader(...)$Read()
+}
+