net/HostParser: use std::string_view instead of StringView

src/net/HostParser.cxx

@@ -1,5 +1,5 @@
 /*
- * Copyright 2007-2020 CM4all GmbH
+ * Copyright 2007-2022 CM4all GmbH
  * All rights reserved.
  *
  * author: Max Kellermann <mk@cm4all.com>
@@ -83,10 +83,22 @@ FindIPv6End(const char *p) noexcept
 	return p;
 }
 
+static constexpr std::string_view
+SV(const char *begin, const char *end) noexcept
+{
+#if __cplusplus >= 202002 && !defined(__clang__)
+	return {begin, end};
+#else
+	/* kludge for libc++ which does not yet implement the C++20
+	   iterator constructor */
+	return {begin, std::size_t(end - begin)};
+#endif
+}
+
 ExtractHostResult
 ExtractHost(const char *src) noexcept
 {
-	ExtractHostResult result{nullptr, src};
+	ExtractHostResult result{{}, src};
 	const char *hostname;
 
 	if (IsValidHostnameChar(*src)) {
@@ -100,7 +112,7 @@ ExtractHost(const char *src) noexcept
 					/* found a second colon: assume it's an IPv6
 					   address */
 					result.end = FindIPv6End(src + 1);
-					result.host = {hostname, result.end};
+					result.host = SV(hostname, result.end);
 					return result;
 				} else
 					/* remember the position of the first colon */
@@ -115,11 +127,11 @@ ExtractHost(const char *src) noexcept
 			src = colon;
 
 		result.end = src;
-		result.host = {hostname, result.end};
+		result.host = SV(hostname, result.end);
 	} else if (src[0] == ':' && src[1] == ':') {
 		/* IPv6 address beginning with "::" */
 		result.end = FindIPv6End(src + 2);
-		result.host = {src, result.end};
+		result.host = SV(src, result.end);
 	} else if (src[0] == '[') {
 		/* "[hostname]:port" (IPv6?) */
 
@@ -129,7 +141,7 @@ ExtractHost(const char *src) noexcept
 			/* failed, return nullptr */
 			return result;
 
-		result.host = {hostname, end};
+		result.host = SV(hostname, end);
 		result.end = end + 1;
 	} else {
 		/* failed, return nullptr */

src/net/HostParser.hxx

@@ -1,5 +1,5 @@
 /*
- * Copyright 2007-2020 CM4all GmbH
+ * Copyright 2007-2022 CM4all GmbH
  * All rights reserved.
  *
  * author: Max Kellermann <mk@cm4all.com>
@@ -30,10 +30,9 @@
  * OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef NET_HOST_PARSER_HXX
+#pragma once
-#define NET_HOST_PARSER_HXX
 
-#include "util/StringView.hxx"
+#include <string_view>
 
 /**
  * Result type for ExtractHost().
@@ -44,7 +43,7 @@ struct ExtractHostResult {
 	 *
 	 * If nothing was parsed, then this is nullptr.
 	 */
-	StringView host;
+	std::string_view host;
 
 	/**
 	 * Pointer to the first character that was not parsed.  On
@@ -57,7 +56,7 @@ struct ExtractHostResult {
 	const char *end;
 
 	constexpr bool HasFailed() const noexcept {
-		return host == nullptr;
+		return host.data() == nullptr;
 	}
 };
 
@@ -71,5 +70,3 @@ struct ExtractHostResult {
 [[gnu::pure]]
 ExtractHostResult
 ExtractHost(const char *src) noexcept;
-
-#endif

src/net/Resolver.cxx

@@ -108,11 +108,11 @@ Resolve(const char *host_and_port, int default_port,
 		if (eh.HasFailed())
 			throw std::runtime_error("Failed to extract host name");
 
-		if (eh.host.size >= sizeof(buffer))
+		if (eh.host.size() >= sizeof(buffer))
 			throw std::runtime_error("Host name too long");
 
-		memcpy(buffer, eh.host.data, eh.host.size);
+		memcpy(buffer, eh.host.data(), eh.host.size());
-		buffer[eh.host.size] = 0;
+		buffer[eh.host.size()] = 0;
 		host = buffer;
 
 #ifndef _WIN32