Use drogon::OStringStream instead of std::stringstream in text template (#322)

CMakeLists.txt

@@ -425,7 +425,8 @@ set(DROGON_UTIL_HEADERS
     lib/inc/drogon/utils/Utilities.h
     lib/inc/drogon/utils/any.h
     lib/inc/drogon/utils/string_view.h
-    lib/inc/drogon/utils/HttpConstraint.h)
+    lib/inc/drogon/utils/HttpConstraint.h
+    lib/inc/drogon/utils/OStringStream.h)
 install(FILES ${DROGON_UTIL_HEADERS}
         DESTINATION ${INSTALL_INCLUDE_DIR}/drogon/utils)
 

drogon_ctl/create_view.cc

@@ -330,8 +330,8 @@ void create_view::newViewSourceFile(std::ofstream &file,
     file << "//this file is generated by program(drogon_ctl) "
             "automatically,don't modify it!\n";
     file << "#include \"" << className << ".h\"\n";
+    file << "#include <drogon/utils/OStringStream.h>\n";
     file << "#include <string>\n";
-    file << "#include <sstream>\n";
     file << "#include <map>\n";
     file << "#include <vector>\n";
     file << "#include <set>\n";
@@ -416,7 +416,7 @@ void create_view::newViewSourceFile(std::ofstream &file,
     std::string streamName = className + "_tmp_stream";
 
     // oSrcFile <<"\tstd::string "<<bodyName<<";\n";
-    file << "\tstd::stringstream " << streamName << ";\n";
+    file << "\tdrogon::OStringStream " << streamName << ";\n";
     int cxx_flag = 0;
     while (infile.getline(line, sizeof(line)))
     {
@@ -428,6 +428,6 @@ void create_view::newViewSourceFile(std::ofstream &file,
         }
         parseLine(file, buffer, streamName, viewDataName, cxx_flag);
     }
-
-    file << "return " << streamName << ".str();\n}\n";
+    file << "std::string ret{std::move(" << streamName << ".str())};\n";
+    file << "return ret;\n}\n";
 }

lib/inc/drogon/utils/OStringStream.h

@@ -0,0 +1,140 @@
+/**
+ *
+ *  OStringStream.h
+ *  An Tao
+ *
+ *  Copyright 2018, An Tao.  All rights reserved.
+ *  https://github.com/an-tao/drogon
+ *  Use of this source code is governed by a MIT license
+ *  that can be found in the License file.
+ *
+ *  Drogon
+ *
+ */
+
+#pragma once
+#include <string>
+#include <sstream>
+#include <drogon/utils/string_view.h>
+
+namespace drogon
+{
+namespace internal
+{
+template <typename T>
+struct CanConvertToString
+{
+    using Type = std::remove_reference_t<std::remove_cv_t<T>>;
+
+  private:
+    using yes = std::true_type;
+    using no = std::false_type;
+
+    template <typename U>
+    static auto test(int) -> decltype(std::to_string(U{}), yes());
+
+    template <typename>
+    static no test(...);
+
+  public:
+    static constexpr bool value =
+        std::is_same<decltype(test<Type>(0)), yes>::value;
+};
+}  // namespace internal
+class OStringStream
+{
+  public:
+    OStringStream() = default;
+    void reserve(size_t size)
+    {
+        buffer_.reserve(size);
+    }
+    template <typename T>
+    std::enable_if_t<!internal::CanConvertToString<T>::value, OStringStream&>
+    operator<<(T&& value)
+    {
+        std::stringstream ss;
+        ss << std::forward<T>(value);
+        buffer_.append(ss.str());
+        return *this;
+    }
+    template <typename T>
+    std::enable_if_t<internal::CanConvertToString<T>::value, OStringStream&>
+    operator<<(T&& value)
+    {
+        buffer_.append(std::to_string(std::forward<T>(value)));
+        return *this;
+    }
+    template <int N>
+    OStringStream& operator<<(const char (&buf)[N])
+    {
+        buffer_.append(buf, N - 1);
+        return *this;
+    }
+    OStringStream& operator<<(const string_view& str)
+    {
+        buffer_.append(str.data(), str.length());
+        return *this;
+    }
+    OStringStream& operator<<(string_view&& str)
+    {
+        buffer_.append(str.data(), str.length());
+        return *this;
+    }
+
+    OStringStream& operator<<(const std::string& str)
+    {
+        buffer_.append(str);
+        return *this;
+    }
+    OStringStream& operator<<(std::string&& str)
+    {
+        buffer_.append(std::move(str));
+        return *this;
+    }
+
+    OStringStream& operator<<(const double& d)
+    {
+        std::stringstream ss;
+        ss << d;
+        buffer_.append(ss.str());
+        return *this;
+    }
+
+    OStringStream& operator<<(const float& f)
+    {
+        std::stringstream ss;
+        ss << f;
+        buffer_.append(ss.str());
+        return *this;
+    }
+
+    OStringStream& operator<<(double&& d)
+    {
+        std::stringstream ss;
+        ss << d;
+        buffer_.append(ss.str());
+        return *this;
+    }
+
+    OStringStream& operator<<(float&& f)
+    {
+        std::stringstream ss;
+        ss << f;
+        buffer_.append(ss.str());
+        return *this;
+    }
+
+    std::string& str()
+    {
+        return buffer_;
+    }
+    const std::string& str() const
+    {
+        return buffer_;
+    }
+
+  private:
+    std::string buffer_;
+};
+}  // namespace drogon

lib/src/HttpResponseImpl.cc

@@ -37,8 +37,6 @@ static HttpResponsePtr genHttpResponse(std::string viewName,
     if (templ)
     {
         auto res = HttpResponse::newHttpResponse();
-        res->setStatusCode(k200OK);
-        res->setContentTypeCode(CT_TEXT_HTML);
         res->setBody(templ->genText(data));
         return res;
     }
@@ -255,7 +253,7 @@ void HttpResponseImpl::makeHeaderString(
         {
             if (closeConnection_)
             {
-                if(version_ == Version::kHttp11)
+                if (version_ == Version::kHttp11)
                 {
                     headerStringPtr->append("Connection: close\r\n");
                 }

unittest/CMakeLists.txt

@@ -3,13 +3,15 @@ add_executable(drobject_unittest DrObjectUnittest.cpp)
 add_executable(gzip_unittest GzipUnittest.cpp)
 add_executable(md5_unittest MD5Unittest.cpp ../lib/src/ssl_funcs/Md5.cc)
 add_executable(sha1_unittest SHA1Unittest.cpp ../lib/src/ssl_funcs/Sha1.cc)
+add_executable(ostringstream_unittest OStringStreamUnitttest.cpp)
 
 set(UNITTEST_TARGETS
     msgbuffer_unittest
     drobject_unittest
     gzip_unittest
     md5_unittest
-    sha1_unittest)
+    sha1_unittest
+    ostringstream_unittest)
 
 set_property(TARGET ${UNITTEST_TARGETS}
              PROPERTY CXX_STANDARD ${DROGON_CXX_STANDARD})

unittest/OStringStreamUnitttest.cpp

@@ -0,0 +1,62 @@
+#include <gtest/gtest.h>
+#include <drogon/utils/OStringStream.h>
+#include <string>
+#include <iostream>
+
+TEST(OStringStreamTest, interger)
+{
+    drogon::OStringStream ss;
+    ss << 12;
+    ss << 345L;
+    EXPECT_EQ(ss.str(), "12345");
+}
+
+TEST(OStringStreamTest, float_number)
+{
+    drogon::OStringStream ss;
+    ss << 3.14f;
+    ss << 3.1416;
+    EXPECT_EQ(ss.str(), "3.143.1416");
+}
+
+TEST(OStringStreamTest, literal_string)
+{
+    drogon::OStringStream ss;
+    ss << "hello";
+    ss << " world";
+    EXPECT_EQ(ss.str(), "hello world");
+}
+
+TEST(OStringStreamTest, string_view)
+{
+    drogon::OStringStream ss;
+    ss << drogon::string_view("hello");
+    ss << drogon::string_view(" world");
+    EXPECT_EQ(ss.str(), "hello world");
+}
+
+TEST(OStringStreamTest, std_string)
+{
+    drogon::OStringStream ss;
+    ss << std::string("hello");
+    ss << std::string(" world");
+    EXPECT_EQ(ss.str(), "hello world");
+}
+
+TEST(OStringStreamTest, mix)
+{
+    drogon::OStringStream ss;
+    ss << std::string("hello");
+    ss << drogon::string_view(" world");
+    ss << "!";
+    ss << 123;
+    ss << 3.14f;
+
+    EXPECT_EQ(ss.str(), "hello world!1233.14");
+}
+
+int main(int argc, char **argv)
+{
+    testing::InitGoogleTest(&argc, argv);
+    return RUN_ALL_TESTS();
+}