Move internal details from one source file to another more appropriate source

file.

PiperOrigin-RevId: 484419458
Change-Id: Ic2c1afa1a3434ac071c01ae2e6c75dee41b1f069

CMake/AbseilDll.cmake

@@ -243,6 +243,7 @@ set(ABSL_INTERNAL_DLL_FILES
   "strings/internal/stl_type_traits.h"
   "strings/internal/string_constant.h"
   "strings/internal/stringify_sink.h"
+  "strings/internal/stringify_sink.cc"
   "strings/match.cc"
   "strings/match.h"
   "strings/numbers.cc"

absl/strings/BUILD.bazel

@@ -43,6 +43,7 @@ cc_library(
         "internal/stl_type_traits.h",
         "internal/str_join_internal.h",
         "internal/str_split_internal.h",
+        "internal/stringify_sink.cc",
         "internal/stringify_sink.h",
         "match.cc",
         "numbers.cc",

absl/strings/CMakeLists.txt

@@ -44,6 +44,7 @@ absl_cc_library(
     "internal/memutil.cc"
     "internal/memutil.h"
     "internal/stringify_sink.h"
+    "internal/stringify_sink.cc"
     "internal/stl_type_traits.h"
     "internal/str_join_internal.h"
     "internal/str_split_internal.h"

absl/strings/internal/stringify_sink.cc

@@ -0,0 +1,28 @@
+// Copyright 2022 The Abseil Authors
+//
+// Licensed 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
+//
+//     https://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 "absl/strings/internal/stringify_sink.h"
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace strings_internal {
+
+void StringifySink::Append(size_t count, char ch) { buffer_.append(count, ch); }
+
+void StringifySink::Append(string_view v) {
+  buffer_.append(v.data(), v.size());
+}
+
+}  // namespace strings_internal
+ABSL_NAMESPACE_END
+}  // namespace absl

absl/strings/str_cat.cc

@@ -30,15 +30,6 @@
 namespace absl {
 ABSL_NAMESPACE_BEGIN
 
-namespace strings_internal {
-void StringifySink::Append(size_t count, char ch) { buffer_.append(count, ch); }
-
-void StringifySink::Append(string_view v) {
-  buffer_.append(v.data(), v.size());
-}
-
-}  // namespace strings_internal
-
 AlphaNum::AlphaNum(Hex hex) {
   static_assert(numbers_internal::kFastToBufferSize >= 32,
                 "This function only works when output buffer >= 32 bytes long");