implement IO.(bin)read which accept :all

IO.(bin)read(dev, `:all`) reads all contents from device

Signed-off-by: José Valim <jose.valim@plataformatec.com.br>

lib/elixir/lib/io.ex

@@ -44,7 +44,9 @@ defmodule IO do
 
   @doc """
   Reads `count` characters from the IO device or until
-  the end of the line if `:line` is given. It returns:
+  the end of the line if `:line` is given. If `:all` is
+  given, returns empty string instead of `:eof`.
+  It returns:
 
     * `data` - the input characters
 
@@ -54,9 +56,21 @@ defmodule IO do
       for instance, `{:error, :estale}` if reading from an
       NFS volume
   """
-  @spec read(device, :line | non_neg_integer) :: chardata | nodata
+  @spec read(device, :all | :line | non_neg_integer) :: chardata | nodata
   def read(device \\ group_leader, chars_or_line)
 
+  def read(device, :all) do
+    do_read_all(map_dev(device), "")
+  end
+
+  defp do_read_all(mapped_dev, acc) do
+    case :io.get_line(mapped_dev, "") do
+      line when is_binary(line) -> do_read_all(mapped_dev, acc <> line)
+      :eof -> acc
+      other -> other
+    end
+  end
+
   def read(device, :line) do
     :io.get_line(map_dev(device), '')
   end
@@ -67,7 +81,9 @@ defmodule IO do
 
   @doc """
   Reads `count` bytes from the IO device or until
-  the end of the line if `:line` is given. It returns:
+  the end of the line if `:line` is given. If `:all` is
+  given, returns empty string instead of `:eof`.
+  It returns:
 
     * `data` - the input characters
 
@@ -80,9 +96,21 @@ defmodule IO do
   Note: do not use this function on IO devices in unicode mode
   as it will return the wrong result.
   """
-  @spec binread(device, :line | non_neg_integer) :: iodata | nodata
+  @spec binread(device, :all | :line | non_neg_integer) :: iodata | nodata
   def binread(device \\ group_leader, chars_or_line)
 
+  def binread(device, :all) do
+    do_binread_all(map_dev(device), "")
+  end
+
+  defp do_binread_all(mapped_dev, acc) do
+    case :file.read_line(mapped_dev) do
+      {:ok, data} -> do_binread_all(mapped_dev, acc <> data)
+      :eof -> acc
+      other -> other
+    end
+  end
+
   def binread(device, :line) do
     case :file.read_line(map_dev(device)) do
       {:ok, data} -> data

lib/elixir/test/elixir/io_test.exs

@@ -58,6 +58,20 @@ defmodule IOTest do
     assert File.close(file) == :ok
   end
 
+  test :readall do
+    {:ok, file} = File.open(Path.expand('fixtures/file.txt', __DIR__))
+    assert "FOO\n" == IO.read(file, :all)
+    assert "" == IO.read(file, :all)
+    assert File.close(file) == :ok
+  end
+
+  test :readall_with_utf8_and_binary do
+    {:ok, file} = File.open(Path.expand('fixtures/utf8.txt', __DIR__), [:utf8])
+    assert "Русский\n日\n" == IO.read(file, :all)
+    assert "" == IO.read(file, :all)
+    assert File.close(file) == :ok
+  end
+
   test :readline do
     {:ok, file} = File.open(Path.expand('fixtures/file.txt', __DIR__))
     assert "FOO\n" == IO.read(file, :line)
@@ -72,6 +86,13 @@ defmodule IOTest do
     assert File.close(file) == :ok
   end
 
+  test :binreadall do
+    {:ok, file} = File.open(Path.expand('fixtures/utf8.txt', __DIR__))
+    assert "Русский\n日\n" == IO.binread(file, :all)
+    assert "" == IO.binread(file, :all)
+    assert File.close(file) == :ok
+  end
+
   test :binreadline do
     {:ok, file} = File.open(Path.expand('fixtures/utf8.txt', __DIR__))
     assert "Русский\n" == IO.binread(file, :line)