From e6f2cae62404d8f3be44667157387f1e0908f661 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Thu, 9 Sep 2021 20:53:22 +0100
Subject: Introduce MaybeString

Allows at least a string_view, but maybe a string... used when input might need decoding,
but removes the need for a copy when it doesn't.
---
 icespider/common/maybeString.h        | 65 +++++++++++++++++++++++++++++++++++
 icespider/core/xwwwFormUrlEncoded.cpp | 12 ++++---
 icespider/core/xwwwFormUrlEncoded.h   |  5 +--
 icespider/fcgi/cgiRequestBase.h       |  3 +-
 4 files changed, 78 insertions(+), 7 deletions(-)
 create mode 100644 icespider/common/maybeString.h

diff --git a/icespider/common/maybeString.h b/icespider/common/maybeString.h
new file mode 100644
index 0000000..b760faa
--- /dev/null
+++ b/icespider/common/maybeString.h
@@ -0,0 +1,65 @@
+#ifndef ICESPIDER_COMMON_MAYBESTRING_H
+#define ICESPIDER_COMMON_MAYBESTRING_H
+
+#include <string>
+#include <string_view>
+#include <variant>
+
+namespace IceSpider {
+	class MaybeString {
+	public:
+		MaybeString() { }
+
+		// NOLINTNEXTLINE(hicpp-explicit-conversions)
+		inline MaybeString(std::string s) : value_ {std::move(s)} { }
+
+		// NOLINTNEXTLINE(hicpp-explicit-conversions)
+		inline MaybeString(std::string_view s) : value_ {std::move(s)} { }
+
+		[[nodiscard]] inline operator std::string_view() const
+		{
+			if (value_.index() == 0) {
+				return std::get<0>(value_);
+			}
+			return std::get<1>(value_);
+		}
+
+		[[nodiscard]] inline std::string_view
+		value() const
+		{
+			return *this;
+		}
+
+		[[nodiscard]] inline bool
+		isString() const
+		{
+			return value_.index() > 0;
+		}
+
+		[[nodiscard]] inline bool
+		operator<(const MaybeString & o) const
+		{
+			return value() < o.value();
+		}
+
+		[[nodiscard]] inline bool
+		operator<(const std::string_view & o) const
+		{
+			return value() < o;
+		}
+
+	private:
+		using value_type = std::variant<std::string_view, std::string>;
+		value_type value_;
+	};
+};
+
+namespace std {
+	inline std::ostream &
+	operator<<(std::ostream & s, const IceSpider::MaybeString & ms)
+	{
+		return s << ms.value();
+	}
+}
+
+#endif
diff --git a/icespider/core/xwwwFormUrlEncoded.cpp b/icespider/core/xwwwFormUrlEncoded.cpp
index e594bb0..7a785bd 100644
--- a/icespider/core/xwwwFormUrlEncoded.cpp
+++ b/icespider/core/xwwwFormUrlEncoded.cpp
@@ -108,6 +108,7 @@ namespace IceSpider {
 	static constexpr const std::string_view FALSE = "false";
 	static constexpr const std::string_view KEY = "key";
 	static constexpr const std::string_view VALUE = "value";
+	static constexpr const std::string_view URL_ESCAPES = "%+";
 
 	XWwwFormUrlEncoded::XWwwFormUrlEncoded(std::istream & in) :
 		input(std::istreambuf_iterator<char>(in), std::istreambuf_iterator<char>())
@@ -139,7 +140,7 @@ namespace IceSpider {
 
 	class SetFromString : public Slicer::ValueSource {
 	public:
-		explicit SetFromString(const std::string & v) : s(v) { }
+		explicit SetFromString(const MaybeString & v) : s(v) { }
 
 		void
 		set(bool & t) const override
@@ -176,7 +177,7 @@ namespace IceSpider {
 		SET(Ice::Double);
 
 	private:
-		const std::string & s;
+		const MaybeString & s;
 	};
 
 	std::string
@@ -219,9 +220,12 @@ namespace IceSpider {
 		urlencoderange(std::ostream_iterator<decltype(*i)>(o), i, e);
 	}
 
-	std::string
+	MaybeString
 	XWwwFormUrlEncoded::urldecode(std::string_view::const_iterator i, std::string_view::const_iterator e)
 	{
+		if (std::find_first_of(i, e, URL_ESCAPES.begin(), URL_ESCAPES.end()) == e) {
+			return std::string_view {i, e};
+		}
 		std::string t;
 		t.reserve(static_cast<std::string::size_type>(std::distance(i, e)));
 		while (i != e) {
@@ -252,7 +256,7 @@ namespace IceSpider {
 		for (; pi != decltype(pi)(); ++pi) {
 			auto eq = std::find(pi->begin(), pi->end(), '=');
 			if (eq == pi->end()) {
-				h(urldecode(pi->begin(), pi->end()), std::string());
+				h(urldecode(pi->begin(), pi->end()), {});
 			}
 			else {
 				h(urldecode(pi->begin(), eq), urldecode(eq + 1, pi->end()));
diff --git a/icespider/core/xwwwFormUrlEncoded.h b/icespider/core/xwwwFormUrlEncoded.h
index e0f8053..6c266b6 100644
--- a/icespider/core/xwwwFormUrlEncoded.h
+++ b/icespider/core/xwwwFormUrlEncoded.h
@@ -2,13 +2,14 @@
 #define ICESPIDER_CGI_XWWWFORMURLENCODED_H
 
 #include <boost/algorithm/string/split.hpp>
+#include <maybeString.h>
 #include <slicer/serializer.h>
 #include <visibility.h>
 
 namespace IceSpider {
 	class XWwwFormUrlEncoded : public Slicer::Deserializer {
 	public:
-		using KVh = std::function<void(std::string &&, std::string &&)>;
+		using KVh = std::function<void(MaybeString &&, MaybeString &&)>;
 
 		explicit XWwwFormUrlEncoded(std::istream & in);
 
@@ -16,7 +17,7 @@ namespace IceSpider {
 		DLL_PUBLIC static void iterateVars(
 				const std::string_view & input, const KVh & h, const std::string_view & split);
 
-		DLL_PUBLIC static std::string urldecode(std::string_view::const_iterator s, std::string_view::const_iterator);
+		DLL_PUBLIC static MaybeString urldecode(std::string_view::const_iterator s, std::string_view::const_iterator);
 		DLL_PUBLIC static std::string urlencode(std::string_view::const_iterator s, std::string_view::const_iterator);
 		DLL_PUBLIC static void urlencodeto(
 				std::ostream &, std::string_view::const_iterator s, std::string_view::const_iterator);
diff --git a/icespider/fcgi/cgiRequestBase.h b/icespider/fcgi/cgiRequestBase.h
index 774f06d..fdc82d7 100644
--- a/icespider/fcgi/cgiRequestBase.h
+++ b/icespider/fcgi/cgiRequestBase.h
@@ -5,6 +5,7 @@
 #include <core.h>
 #include <flatMap.h>
 #include <ihttpRequest.h>
+#include <maybeString.h>
 #include <string_view>
 
 namespace IceSpider {
@@ -17,7 +18,7 @@ namespace IceSpider {
 	public:
 		using VarMap = flatmap<std::string_view, std::string_view>;
 		using HdrMap = flatmap<std::string_view, std::string_view, AdHoc::case_less>;
-		using StrMap = flatmap<std::string, std::string>;
+		using StrMap = flatmap<MaybeString, MaybeString>;
 
 		[[nodiscard]] const PathElements & getRequestPath() const override;
 		[[nodiscard]] PathElements & getRequestPath() override;
-- 
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