Using wostringstream only on Windows (#21938)

### Description
Using wostringstream only on Windows



### Motivation and Context
From line
[62](https://github.com/microsoft/onnxruntime/pull/21938/files#diff-47776d020ac08134de4059eab473550237f4999c598ab56afad3676d2f193edcR62),
currently, `stream_` can be either `wostringstream` or `ostringstream`
depending on the OS, however, for Unix like system, `stream_` should be
`ostringstream`, instead of.

onnxruntime/core/common/logging/sinks/file_sink.h

@@ -8,6 +8,7 @@
 
 namespace onnxruntime {
 namespace logging {
+#ifndef _WIN32
 /// <summary>
 /// ISink that writes to a file.
 /// </summary>
@@ -47,5 +48,47 @@ class FileSink : public OStreamSink {
   std::unique_ptr<std::ofstream> file_;
   bool filter_user_data_;
 };
+
+#else
+/// <summary>
+/// ISink that writes to a file.
+/// </summary>
+/// <seealso cref="ISink" />
+class FileSink : public WOStreamSink {
+ public:
+  /// <summary>
+  /// Initializes a new instance of the <see cref="FileSink" /> class.
+  /// </summary>
+  /// <param name="filename">The filename to write to.</param>
+  /// <param name="append">If set to <c>true</c> [append to file]. Otherwise truncate.</param>
+  /// <param name="filter_user_data">If set to <c>true</c> [removes user data].</param>
+  /// <remarks>Filtering of user data can alternatively be done at the <see cref="LoggingManager" /> level.</remarks>
+  FileSink(std::unique_ptr<std::wofstream> file, bool filter_user_data)
+      : WOStreamSink(*file, /*flush*/ true), file_(std::move(file)), filter_user_data_{filter_user_data} {
+  }
+
+  /// <summary>
+  /// Initializes a new instance of the <see cref="FileSink" /> class.
+  /// </summary>
+  /// <param name="filename">The filename to write to.</param>
+  /// <param name="append">If set to <c>true</c> [append to file]. Otherwise truncate.</param>
+  /// <param name="filter_user_data">If set to <c>true</c> [removes user data].</param>
+  /// <remarks>Filtering of user data can alternatively be done at the <see cref="LoggingManager" /> level.</remarks>
+  FileSink(const std::wstring& filename, bool append, bool filter_user_data)
+      : FileSink{std::make_unique<std::wofstream>(filename, std::ios::out | (append ? std::ios::app : std::ios::trunc)),
+                 filter_user_data} {
+  }
+
+ private:
+  void SendImpl(const Timestamp& timestamp, const std::string& logger_id, const Capture& message) override {
+    if (!filter_user_data_ || message.DataType() != DataType::USER) {
+      WOStreamSink::SendImpl(timestamp, logger_id, message);
+    }
+  }
+
+  std::unique_ptr<std::wofstream> file_;
+  bool filter_user_data_;
+};
+#endif
 }  // namespace logging
 }  // namespace onnxruntime

onnxruntime/core/common/logging/sinks/ostream_sink.cc

@@ -21,6 +21,7 @@ struct Color {
 };
 #endif
 
+#ifndef _WIN32
 void OStreamSink::SendImpl(const Timestamp& timestamp, const std::string& logger_id, const Capture& message) {
   // operator for formatting of timestamp in ISO8601 format including microseconds
   using timestamp_ns::operator<<;
@@ -62,7 +63,7 @@ void OStreamSink::SendImpl(const Timestamp& timestamp, const std::string& logger
     stream_->flush();
   }
 }
-#ifdef _WIN32
+#else
 void WOStreamSink::SendImpl(const Timestamp& timestamp, const std::string& logger_id, const Capture& message) {
   // operator for formatting of timestamp in ISO8601 format including microseconds
   using date::operator<<;

onnxruntime/core/common/logging/sinks/ostream_sink.h

@@ -12,6 +12,7 @@
 
 namespace onnxruntime {
 namespace logging {
+#ifndef _WIN32
 /// <summary>
 /// A std::ostream based ISink
 /// </summary>
@@ -29,7 +30,7 @@ class OStreamSink : public ISink {
   std::ostream* stream_;
   const bool flush_;
 };
-#ifdef _WIN32
+#else
 /// <summary>
 /// A std::wostream based ISink
 /// </summary>

onnxruntime/test/common/logging/logging_test.cc

@@ -240,18 +240,30 @@ TEST_F(LoggingTestsFixture, TestVLog) {
 #endif
 }
 
+#ifdef _WIN32
+class CTestSink : public WOStreamSink {
+ public:
+  CTestSink(std::wostringstream& stream) : WOStreamSink(stream, /*flush*/ true) {
+  }
+};
+#else
 class CTestSink : public OStreamSink {
  public:
   CTestSink(std::ostringstream& stream) : OStreamSink(stream, /*flush*/ true) {
   }
 };
+#endif
 
 TEST_F(LoggingTestsFixture, TestTruncation) {
   const std::string logger_id{"TestTruncation"};
   const Severity min_log_level = Severity::kVERBOSE;
   constexpr bool filter_user_data = false;
 
+#ifdef _WIN32
+  std::wostringstream out;
+#else
   std::ostringstream out;
+#endif
   auto* sink_ptr = new CTestSink{out};
 
   LoggingManager manager{std::unique_ptr<ISink>(sink_ptr), min_log_level, filter_user_data,
@@ -261,8 +273,11 @@ TEST_F(LoggingTestsFixture, TestTruncation) {
 
   // attempt to print string longer than hard-coded 2K buffer limit
   LOGF(*logger, ERROR, "%s", std::string(4096, 'a').c_str());
-
+#ifdef _WIN32
+  EXPECT_THAT(out.str(), HasSubstr(L"[...truncated...]"));
+#else
   EXPECT_THAT(out.str(), HasSubstr("[...truncated...]"));
+#endif
 }
 
 TEST_F(LoggingTestsFixture, TestStreamMacroFromConditionalWithoutCompoundStatement) {

onnxruntime/test/common/logging/sinks_test.cc

@@ -1,6 +1,6 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
-
+#include "core/common/common.h"
 #include "core/common/logging/capture.h"
 #include "core/common/logging/logging.h"
 #include "core/common/logging/sinks/cerr_sink.h"
@@ -126,9 +126,13 @@ TEST(LoggingTests, TestFileSink) {
 
   // create scoped manager so sink gets destroyed once done
   {
+#ifdef _WIN32
+    LoggingManager manager{std::make_unique<FileSink>(onnxruntime::ToWideString(filename), false, false),
+                           min_log_level, false, InstanceType::Temporal};
+#else
     LoggingManager manager{std::unique_ptr<ISink>{new FileSink{filename, false, false}},
                            min_log_level, false, InstanceType::Temporal};
-
+#endif
     auto logger = manager.CreateLogger(logid);
 
     LOGS(*logger, WARNING) << message;