From c4d727cbe684877eaa334fee804b0601e9e4e74c Mon Sep 17 00:00:00 2001
From: An Tao <antao2002@gmail.com>
Date: Fri, 14 Aug 2020 08:10:56 +0800
Subject: [PATCH] Fix compilation warning of sprintf function (#537)

---
 lib/src/HttpRequestImpl.cc  |  2 +-
 lib/src/HttpResponseImpl.cc |  5 +++--
 lib/src/HttpUtils.h         | 30 ++++++++++++++++++++++++++++++
 3 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/lib/src/HttpRequestImpl.cc b/lib/src/HttpRequestImpl.cc
index ed67dbea3f..fe71416c45 100644
--- a/lib/src/HttpRequestImpl.cc
+++ b/lib/src/HttpRequestImpl.cc
@@ -316,7 +316,7 @@ void HttpRequestImpl::appendToBuffer(trantor::MsgBuffer *output) const
         char buf[64];
         auto len = snprintf(buf,
                             sizeof(buf),
-                            "Content-Length: %lu\r\n",
+                            contentLengthFormatString<decltype(content.length())>(),
                             content.length() + content_.length());
         output->append(buf, len);
         if (contentTypeString_.empty())
diff --git a/lib/src/HttpResponseImpl.cc b/lib/src/HttpResponseImpl.cc
index ecebdec3b7..abd8a17240 100644
--- a/lib/src/HttpResponseImpl.cc
+++ b/lib/src/HttpResponseImpl.cc
@@ -30,6 +30,7 @@ using namespace drogon;
 
 namespace drogon
 {
+
 // "Fri, 23 Aug 2019 12:58:03 GMT" length = 29
 static const size_t httpFullDateStringLength = 29;
 static inline void doResponseCreateAdvices(
@@ -272,7 +273,7 @@ void HttpResponseImpl::makeHeaderString(trantor::MsgBuffer &buffer)
             auto bodyLength = bodyPtr_ ? bodyPtr_->length() : 0;
             len = snprintf(buffer.beginWrite(),
                            buffer.writableBytes(),
-                           "Content-Length: %lu\r\n",
+                           contentLengthFormatString<decltype(bodyLength)>(),
                            bodyLength);
         }
         else
@@ -285,7 +286,7 @@ void HttpResponseImpl::makeHeaderString(trantor::MsgBuffer &buffer)
             }
             len = snprintf(buffer.beginWrite(),
                            buffer.writableBytes(),
-                           "Content-Length: %lld\r\n",
+                           contentLengthFormatString<decltype(filestat.st_size)>(),
                            filestat.st_size);
         }
         buffer.hasWritten(len);
diff --git a/lib/src/HttpUtils.h b/lib/src/HttpUtils.h
index 5990048832..26691b97db 100644
--- a/lib/src/HttpUtils.h
+++ b/lib/src/HttpUtils.h
@@ -25,4 +25,34 @@ ContentType parseContentType(const string_view &contentType);
 const string_view &webContentTypeToString(ContentType contenttype);
 const string_view &statusCodeToString(int code);
 ContentType getContentType(const std::string &fileName);
+template <typename T>
+inline constexpr const char *contentLengthFormatString()
+{
+    return "Content-Length: %d\r\n";
+}
+template <>
+inline constexpr const char *contentLengthFormatString<unsigned int>()
+{
+    return "Content-Length: %u\r\n";
+}
+template <>
+inline constexpr const char *contentLengthFormatString<long>()
+{
+    return "Content-Length: %ld\r\n";
+}
+template <>
+inline constexpr const char *contentLengthFormatString<unsigned long>()
+{
+    return "Content-Length: %lu\r\n";
+}
+template <>
+inline constexpr const char *contentLengthFormatString<long long>()
+{
+    return "Content-Length: %lld\r\n";
+}
+template <>
+inline constexpr const char *contentLengthFormatString<unsigned long long>()
+{
+    return "Content-Length: %llu\r\n";
+}
 }  // namespace drogon