Update feather factories

feather_table_reader -> FeatherTableReader
feather_table_writer -> FeatherTableWriter

Author: romainfrancois

r/NAMESPACE

@@ -8,6 +8,12 @@ S3method("==","arrow::RecordBatch")
 S3method("==","arrow::ipc::Message")
 S3method(BufferReader,"arrow::Buffer")
 S3method(BufferReader,default)
+S3method(FeatherTableReader,"arrow::io::RandomAccessFile")
+S3method(FeatherTableReader,"arrow::ipc::feather::TableReader")
+S3method(FeatherTableReader,character)
+S3method(FeatherTableReader,default)
+S3method(FeatherTableReader,fs_path)
+S3method(FeatherTableWriter,"arrow::io::OutputStream")
 S3method(FixedSizeBufferWriter,"arrow::Buffer")
 S3method(FixedSizeBufferWriter,default)
 S3method(MessageReader,"arrow::io::InputStream")
@@ -33,12 +39,6 @@ S3method(buffer,default)
 S3method(buffer,integer)
 S3method(buffer,numeric)
 S3method(buffer,raw)
-S3method(feather_table_reader,"arrow::io::RandomAccessFile")
-S3method(feather_table_reader,"arrow::ipc::feather::TableReader")
-S3method(feather_table_reader,character)
-S3method(feather_table_reader,default)
-S3method(feather_table_reader,fs_path)
-S3method(feather_table_writer,"arrow::io::OutputStream")
 S3method(length,"arrow::Array")
 S3method(names,"arrow::RecordBatch")
 S3method(print,"arrow-enum")
@@ -70,6 +70,8 @@ S3method(write_feather_RecordBatch,fs_path)
 export(BufferOutputStream)
 export(BufferReader)
 export(DateUnit)
+export(FeatherTableReader)
+export(FeatherTableWriter)
 export(FileMode)
 export(FileOutputStream)
 export(FixedSizeBufferWriter)
@@ -95,8 +97,6 @@ export(date64)
 export(decimal)
 export(default_memory_pool)
 export(dictionary)
-export(feather_table_reader)
-export(feather_table_writer)
 export(field)
 export(float16)
 export(float32)

r/R/feather.R

@@ -35,7 +35,11 @@
     num_columns = function() ipc___feather___TableReader__num_columns(self),
     GetColumnName = function(i) ipc___feather___TableReader__GetColumnName(self, i),
     GetColumn = function(i) shared_ptr(`arrow::Column`, ipc___feather___TableReader__GetColumn(self, i)),
-    Read = function() shared_ptr(`arrow::Table`, ipc___feather___TableReader__Read(self))
+    Read = function(columns) {
+      if (is.null(columns)) {
+        shared_ptr(`arrow::Table`, ipc___feather___TableReader__Read(self))
+      }
+    }
   )
 )
 
@@ -44,12 +48,12 @@
 #' @param stream an OutputStream
 #'
 #' @export
-feather_table_writer <- function(stream) {
-  UseMethod("feather_table_writer")
+FeatherTableWriter <- function(stream) {
+  UseMethod("FeatherTableWriter")
 }
 
 #' @export
-`feather_table_writer.arrow::io::OutputStream` <- function(stream){
+`FeatherTableWriter.arrow::io::OutputStream` <- function(stream){
   unique_ptr(`arrow::ipc::feather::TableWriter`, ipc___feather___TableWriter__Open(stream))
 }
 
@@ -107,7 +111,7 @@ write_feather_RecordBatch <- function(data, stream) {
 #' @export
 #' @method write_feather_RecordBatch arrow::io::OutputStream
 `write_feather_RecordBatch.arrow::io::OutputStream` <- function(data, stream) {
-  ipc___TableWriter__RecordBatch__WriteFeather(feather_table_writer(stream), data)
+  ipc___TableWriter__RecordBatch__WriteFeather(FeatherTableWriter(stream), data)
 }
 
 #' A arrow::ipc::feather::TableReader to read from a file
@@ -117,44 +121,45 @@ write_feather_RecordBatch <- function(data, stream) {
 #' @param ... extra parameters
 #'
 #' @export
-feather_table_reader <- function(file, mmap = TRUE, ...){
-  UseMethod("feather_table_reader")
+FeatherTableReader <- function(file, mmap = TRUE, ...){
+  UseMethod("FeatherTableReader")
 }
 
 #' @export
-feather_table_reader.default <- function(file, mmap = TRUE, ...) {
+FeatherTableReader.default <- function(file, mmap = TRUE, ...) {
   stop("unsupported")
 }
 
 #' @export
-feather_table_reader.character <- function(file, mmap = TRUE, ...) {
-  feather_table_reader(fs::path_abs(file), mmap = mmap, ...)
+FeatherTableReader.character <- function(file, mmap = TRUE, ...) {
+  FeatherTableReader(fs::path_abs(file), mmap = mmap, ...)
 }
 
 #' @export
-feather_table_reader.fs_path <- function(file, mmap = TRUE, ...) {
+FeatherTableReader.fs_path <- function(file, mmap = TRUE, ...) {
   stream <- if(isTRUE(mmap)) mmap_open(file, ...) else ReadableFile(file, ...)
-  feather_table_reader(stream)
+  FeatherTableReader(stream)
 }
 
 #' @export
-`feather_table_reader.arrow::io::RandomAccessFile` <- function(file, mmap = TRUE, ...){
+`FeatherTableReader.arrow::io::RandomAccessFile` <- function(file, mmap = TRUE, ...){
   unique_ptr(`arrow::ipc::feather::TableReader`, ipc___feather___TableReader__Open(file))
 }
 
 #' @export
-`feather_table_reader.arrow::ipc::feather::TableReader` <- function(file, mmap = TRUE, ...){
+`FeatherTableReader.arrow::ipc::feather::TableReader` <- function(file, mmap = TRUE, ...){
   file
 }
 
 #' Read a feather file
 #'
 #' @param file a arrow::ipc::feather::TableReader or whatever the [feather_table_reader()] function can handle
+#' @param columns names if the columns to read. The default `NULL` means all columns
 #' @param ... additional parameters
 #'
 #' @return an arrow::Table
 #'
 #' @export
-read_feather <- function(file, ...){
-  feather_table_reader(file, ...)$Read()
+read_feather <- function(file, columns = NULL, ...){
+  FeatherTableReader(file, ...)$Read(columns)
 }