Extract duplicate parseLine() function to shared utility header

CMakeLists.txt

@@ -732,6 +732,7 @@ set(DROGON_UTIL_HEADERS
     lib/inc/drogon/utils/FunctionTraits.h
     lib/inc/drogon/utils/HttpConstraint.h
     lib/inc/drogon/utils/OStringStream.h
+    lib/inc/drogon/utils/ParsingUtils.h
     lib/inc/drogon/utils/Utilities.h
     lib/inc/drogon/utils/monitoring.h)
 install(FILES ${DROGON_UTIL_HEADERS}

lib/inc/drogon/utils/ParsingUtils.h

@@ -0,0 +1,100 @@
+/**
+ *
+ *  @file ParsingUtils.h
+ *  Shared parsing utilities for HTTP and multipart parsing
+ *
+ *  Copyright 2024, Drogon.  All rights reserved.
+ *  https://github.com/drogonframework/drogon
+ *  Use of this source code is governed by a MIT license
+ *  that can be found in the License file.
+ *
+ *  Drogon
+ *
+ */
+
+#pragma once
+
+#include <cctype>
+#include <string_view>
+#include <utility>
+
+namespace drogon
+{
+namespace utils
+{
+
+/**
+ * @brief Check if a string_view starts with another string_view
+ */
+inline bool startsWith(const std::string_view &a, const std::string_view &b)
+{
+    if (a.size() < b.size())
+    {
+        return false;
+    }
+    for (size_t i = 0; i < b.size(); i++)
+    {
+        if (a[i] != b[i])
+        {
+            return false;
+        }
+    }
+    return true;
+}
+
+/**
+ * @brief Check if a string_view starts with another string_view
+ * (case-insensitive)
+ */
+inline bool startsWithIgnoreCase(const std::string_view &a,
+                                 const std::string_view &b)
+{
+    if (a.size() < b.size())
+    {
+        return false;
+    }
+    for (size_t i = 0; i < b.size(); i++)
+    {
+        const auto lhs = std::tolower(static_cast<unsigned char>(a[i]));
+        const auto rhs = std::tolower(static_cast<unsigned char>(b[i]));
+        if (lhs != rhs)
+        {
+            return false;
+        }
+    }
+    return true;
+}
+
+/**
+ * @brief Parse a single HTTP header line into name and value
+ * @param begin Pointer to the start of the line
+ * @param end Pointer to the end of the line (not including CRLF)
+ * @return A pair of (header_name, header_value) string_views
+ */
+inline std::pair<std::string_view, std::string_view> parseLine(
+    const char *begin,
+    const char *end)
+{
+    auto p = begin;
+    while (p != end)
+    {
+        if (*p == ':')
+        {
+            if (p + 1 != end && *(p + 1) == ' ')
+            {
+                return std::make_pair(std::string_view(begin, p - begin),
+                                      std::string_view(p + 2, end - p - 2));
+            }
+            else
+            {
+                return std::make_pair(std::string_view(begin, p - begin),
+                                      std::string_view(p + 1, end - p - 1));
+            }
+        }
+        ++p;
+    }
+    return std::make_pair(std::string_view(), std::string_view());
+}
+
+}  // namespace utils
+}  // namespace drogon

lib/src/MultiPart.cc

@@ -18,6 +18,7 @@
 #include "HttpFileImpl.h"
 #include <drogon/MultiPart.h>
 #include <drogon/utils/Utilities.h>
+#include <drogon/utils/ParsingUtils.h>
 #include <drogon/config.h>
 #include <algorithm>
 #include <fcntl.h>
@@ -29,6 +30,7 @@
 #endif
 
 using namespace drogon;
+using drogon::utils::parseLine;
 
 const std::vector<HttpFile> &MultiPartParser::getFiles() const
 {
@@ -87,31 +89,6 @@ int MultiPartParser::parse(const HttpRequestPtr &req)
     return parse(req, contentType.data() + (pos + 9), pos2 - (pos + 9));
 }
 
-static std::pair<std::string_view, std::string_view> parseLine(
-    const char *begin,
-    const char *end)
-{
-    auto p = begin;
-    while (p != end)
-    {
-        if (*p == ':')
-        {
-            if (p + 1 != end && *(p + 1) == ' ')
-            {
-                return std::make_pair(std::string_view(begin, p - begin),
-                                      std::string_view(p + 2, end - p - 2));
-            }
-            else
-            {
-                return std::make_pair(std::string_view(begin, p - begin),
-                                      std::string_view(p + 1, end - p - 1));
-            }
-        }
-        ++p;
-    }
-    return std::make_pair(std::string_view(), std::string_view());
-}
-
 int MultiPartParser::parseEntity(const HttpRequestPtr &req,
                                  const char *begin,
                                  const char *end)

lib/src/MultipartStreamParser.cc

@@ -14,41 +14,12 @@
 
 #include "MultipartStreamParser.h"
 #include <cassert>
+#include <drogon/utils/ParsingUtils.h>
 
 using namespace drogon;
-
-static bool startsWith(const std::string_view &a, const std::string_view &b)
-{
-    if (a.size() < b.size())
-    {
-        return false;
-    }
-    for (size_t i = 0; i < b.size(); i++)
-    {
-        if (a[i] != b[i])
-        {
-            return false;
-        }
-    }
-    return true;
-}
-
-static bool startsWithIgnoreCase(const std::string_view &a,
-                                 const std::string_view &b)
-{
-    if (a.size() < b.size())
-    {
-        return false;
-    }
-    for (size_t i = 0; i < b.size(); i++)
-    {
-        if (::tolower(a[i]) != ::tolower(b[i]))
-        {
-            return false;
-        }
-    }
-    return true;
-}
+using drogon::utils::parseLine;
+using drogon::utils::startsWith;
+using drogon::utils::startsWithIgnoreCase;
 
 MultipartStreamParser::MultipartStreamParser(const std::string &contentType)
 {
@@ -86,32 +57,6 @@ MultipartStreamParser::MultipartStreamParser(const std::string &contentType)
     crlfDashBoundary_ = crlf_ + dash_ + boundary_;
 }
 
-// TODO: same function in HttpRequestParser.cc
-static std::pair<std::string_view, std::string_view> parseLine(
-    const char *begin,
-    const char *end)
-{
-    auto p = begin;
-    while (p != end)
-    {
-        if (*p == ':')
-        {
-            if (p + 1 != end && *(p + 1) == ' ')
-            {
-                return std::make_pair(std::string_view(begin, p - begin),
-                                      std::string_view(p + 2, end - p - 2));
-            }
-            else
-            {
-                return std::make_pair(std::string_view(begin, p - begin),
-                                      std::string_view(p + 1, end - p - 1));
-            }
-        }
-        ++p;
-    }
-    return std::make_pair(std::string_view(), std::string_view());
-}
-
 void drogon::MultipartStreamParser::parse(
     const char *data,
     size_t length,