From 2f05054dd38352ac1969b09b7378289f0d3b4253 Mon Sep 17 00:00:00 2001
From: Victor Zverovich <viz@fb.com>
Date: Wed, 6 May 2020 18:29:04 -0700
Subject: [PATCH] Purge basic_writer

---
 include/fmt/compile.h    |  2 +-
 include/fmt/format-inl.h | 16 +++++-----------
 include/fmt/format.h     |  2 --
 src/os.cc                |  5 +----
 test/format-test.cc      | 15 +++------------
 5 files changed, 10 insertions(+), 30 deletions(-)

diff --git a/include/fmt/compile.h b/include/fmt/compile.h
index 75b33313..215f50bc 100644
--- a/include/fmt/compile.h
+++ b/include/fmt/compile.h
@@ -383,7 +383,7 @@ OutputIt format_default(OutputIt out, T value) {
 
 template <typename Char, typename OutputIt>
 OutputIt format_default(OutputIt out, double value) {
-  writer w(out);
+  basic_writer<buffer_range<char>> w(out);
   w.write(value);
   return w.out();
 }
diff --git a/include/fmt/format-inl.h b/include/fmt/format-inl.h
index 7836255f..4472768b 100644
--- a/include/fmt/format-inl.h
+++ b/include/fmt/format-inl.h
@@ -152,13 +152,10 @@ FMT_FUNC void format_error_code(internal::buffer<char>& out, int error_code,
     ++error_code_size;
   }
   error_code_size += internal::to_unsigned(internal::count_digits(abs_value));
-  internal::writer w(out);
-  if (message.size() <= inline_buffer_size - error_code_size) {
-    w.write(message);
-    w.write(SEP);
-  }
-  w.write(ERROR_STR);
-  w.write(error_code);
+  auto it = std::back_inserter(out);
+  if (message.size() <= inline_buffer_size - error_code_size)
+    format_to(it, "{}{}", message, SEP);
+  format_to(it, "{}{}", ERROR_STR, error_code);
   assert(out.size() <= inline_buffer_size);
 }
 
@@ -1348,10 +1345,7 @@ FMT_FUNC void format_system_error(internal::buffer<char>& out, int error_code,
       int result =
           internal::safe_strerror(error_code, system_message, buf.size());
       if (result == 0) {
-        internal::writer w(out);
-        w.write(message);
-        w.write(": ");
-        w.write(system_message);
+        format_to(std::back_inserter(out), "{}: {}", message, system_message);
         return;
       }
       if (result != ERANGE)
diff --git a/include/fmt/format.h b/include/fmt/format.h
index d9b3d8c2..8395d32e 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -1751,8 +1751,6 @@ template <typename Range> class basic_writer {
   }
 };
 
-using writer = basic_writer<buffer_range<char>>;
-
 template <typename T> struct is_integral : std::is_integral<T> {};
 template <> struct is_integral<int128_t> : std::true_type {};
 template <> struct is_integral<uint128_t> : std::true_type {};
diff --git a/src/os.cc b/src/os.cc
index 10a372a4..328abcee 100644
--- a/src/os.cc
+++ b/src/os.cc
@@ -124,10 +124,7 @@ void internal::format_windows_error(internal::buffer<char>& out, int error_code,
       if (result != 0) {
         utf16_to_utf8 utf8_message;
         if (utf8_message.convert(system_message) == ERROR_SUCCESS) {
-          internal::writer w(out);
-          w.write(message);
-          w.write(": ");
-          w.write(utf8_message);
+          format_to(std::back_inserter(out), "{}: {}", message, utf8_message);
           return;
         }
         break;
diff --git a/test/format-test.cc b/test/format-test.cc
index 66622d7e..46629d1d 100644
--- a/test/format-test.cc
+++ b/test/format-test.cc
@@ -479,13 +479,6 @@ TEST(StringViewTest, Ctor) {
   EXPECT_EQ(4u, string_view(std::string("defg")).size());
 }
 
-TEST(WriterTest, Data) {
-  memory_buffer buf;
-  fmt::internal::writer w(buf);
-  w.write(42);
-  EXPECT_EQ("42", to_string(buf));
-}
-
 TEST(WriterTest, WriteInt) {
   CHECK_WRITE(42);
   CHECK_WRITE(-42);
@@ -548,16 +541,14 @@ TEST(WriterTest, WriteLongDouble) {
 
 TEST(WriterTest, WriteDoubleAtBufferBoundary) {
   memory_buffer buf;
-  fmt::internal::writer writer(buf);
-  for (int i = 0; i < 100; ++i) writer.write(1.23456789);
+  for (int i = 0; i < 100; ++i) fmt::format_to(buf, "{}", 1.23456789);
 }
 
 TEST(WriterTest, WriteDoubleWithFilledBuffer) {
   memory_buffer buf;
-  fmt::internal::writer writer(buf);
   // Fill the buffer.
-  for (int i = 0; i < fmt::inline_buffer_size; ++i) writer.write(' ');
-  writer.write(1.2);
+  for (int i = 0; i < fmt::inline_buffer_size; ++i) fmt::format_to(buf, " ");
+  fmt::format_to(buf, "{}", 1.2);
   fmt::string_view sv(buf.data(), buf.size());
   sv.remove_prefix(fmt::inline_buffer_size);
   EXPECT_EQ("1.2", sv);