Add GenericPath.bySegment2 and .head2 as fully nogc alternatives.

source/vibe/core/path.d

@@ -1,14 +1,14 @@
 /**
 	Contains routines for high level path handling.
 
-	Copyright: © 2012-2018 Sönke Ludwig
+	Copyright: © 2012-2019 Sönke Ludwig
 	License: Subject to the terms of the MIT license, as written in the included LICENSE.txt file.
 	Authors: Sönke Ludwig
 */
 module vibe.core.path;
 
 import std.algorithm.searching : commonPrefix, endsWith, startsWith;
-import std.algorithm.comparison : min;
+import std.algorithm.comparison : equal, min;
 import std.algorithm.iteration : map;
 import std.exception : enforce;
 import std.range : empty, front, popFront, popFrontExactly, takeExactly;
@@ -27,7 +27,6 @@ import std.traits : isInstanceOf;
 Path relativeTo(Path)(Path path, Path base_path) @safe
 	if (isInstanceOf!(GenericPath, Path))
 {
-	import std.algorithm.comparison : equal;
 	import std.array : array, replicate;
 	import std.range : chain, drop, take;
 
@@ -345,6 +344,201 @@ struct GenericPath(F) {
 			else m_front = Segment.init;
 		}
 
+		private void readFront()
+		nothrow {
+			import std.array : array;
+
+			auto n = Format.getFrontNode(m_path);
+			m_path = m_path[n.length .. $];
+
+			char sep = '\0';
+			if (Format.isSeparator(n[$-1])) {
+				sep = n[$-1];
+				n = n[0 .. $-1];
+			}
+			static if (is(typeof(Format.decodeSingleSegment(n)) == string))
+				string ndec = Format.decodeSingleSegment(n);
+			else
+				string ndec = Format.decodeSingleSegment(n).array;
+			m_front = Segment.fromTrustedString(ndec, sep);
+			assert(m_front != Segment.init);
+		}
+	}
+
+	/** A single path segment.
+	*/
+	static struct Segment2 {
+		@safe:
+
+		private {
+			string m_encodedName;
+			char m_separator = 0;
+		}
+
+		/** Constructs a new path segment including an optional trailing
+			separator.
+
+			Params:
+				name = The raw (unencoded) name of the path segment
+				separator = Optional trailing path separator (e.g. `'/'`)
+
+			Throws:
+				A `PathValidationException` is thrown if the name contains
+				characters that are invalid for the path type. In particular,
+				any path separator characters may not be part of the name.
+		*/
+		this(string name, char separator = '\0')
+		{
+			import std.algorithm.searching : any;
+
+			enforce!PathValidationException(separator == '\0' || Format.isSeparator(separator),
+				"Invalid path separator.");
+			auto err = Format.validateDecodedSegment(name);
+			enforce!PathValidationException(err is null, err);
+
+			m_encodedName = Format.encodeSegment(name);
+			m_separator = separator;
+		}
+
+		/** Constructs a path segment without performing validation.
+
+			Note that in debug builds, there are still assertions in place
+			that verify that the provided values are valid.
+
+			Params:
+				name = The raw (unencoded) name of the path segment
+				separator = Optional trailing path separator (e.g. `'/'`)
+		*/
+		static Segment2 fromTrustedString(string name, char separator = '\0')
+		nothrow pure {
+			import std.algorithm.searching : any;
+			assert(separator == '\0' || Format.isSeparator(separator));
+			assert(Format.validateDecodedSegment(name) is null, "Invalid path segment.");
+			return fromTrustedEncodedString(Format.encodeSegment(name), separator);
+		}
+
+		/** Constructs a path segment without performing validation.
+
+			Note that in debug builds, there are still assertions in place
+			that verify that the provided values are valid.
+
+			Params:
+				name = The encoded name of the path segment
+				separator = Optional trailing path separator (e.g. `'/'`)
+		*/
+		static Segment2 fromTrustedEncodedString(string encoded_name, char separator = '\0')
+		nothrow @nogc pure {
+			import std.algorithm.searching : any;
+			import std.utf : byCodeUnit;
+
+			assert(separator == '\0' || Format.isSeparator(separator));
+			assert(!encoded_name.byCodeUnit.any!(c => Format.isSeparator(c)));
+			assert(Format.validatePath(encoded_name) is null, "Invalid path segment.");
+
+			Segment2 ret;
+			ret.m_encodedName = encoded_name;
+			ret.m_separator = separator;
+			return ret;
+		}
+
+		/** The (file/directory) name of the path segment.
+
+			Note: Depending on the path type, this may return a generic range
+			type instead of `string`. Use `name.to!string` in that
+			case if you need an actual `string`.
+		*/
+		@property auto name() const nothrow @nogc { return Format.decodeSingleSegment(m_encodedName); }
+		/// The encoded representation of the path segment name
+		@property string encodedName() const nothrow @nogc { return m_encodedName; }
+		/// The trailing separator (e.g. `'/'`) or `'\0'`.
+		@property char separator() const nothrow @nogc { return m_separator; }
+		/// ditto
+		@property void separator(char ch) {
+			enforce!PathValidationException(ch == '\0' || Format.isSeparator(ch),
+				"Character is not a valid path separator.");
+			m_separator = ch;
+		}
+		/// Returns `true` $(I iff) the segment has a trailing path separator.
+		@property bool hasSeparator() const nothrow @nogc { return m_separator != '\0'; }
+
+		/** Converts the segment to another path type.
+
+			The segment name will be re-validated during the conversion. The
+			separator, if any, will be adopted or replaced by the default
+			separator of the target path type.
+
+			Throws:
+				A `PathValidationException` is thrown if the segment name cannot
+				be represented in the target path format.
+		*/
+		GenericPath!F.Segment2 opCast(T : GenericPath!F.Segment2, F)()
+		{
+			import std.array : array;
+
+			char dsep = '\0';
+			if (m_separator) {
+				if (F.isSeparator(m_separator)) dsep = m_separator;
+				else dsep = F.defaultSeparator;
+			}
+			static if (is(typeof(this.name) == string))
+				string n = this.name;
+			else
+				string n = this.name.array;
+			return GenericPath!F.Segment2(n, dsep);
+		}
+
+		/// Compares two path segment names
+		bool opEquals(Segment2 other)
+		const nothrow @nogc {
+			try return equal(this.name, other.name) && this.hasSeparator == other.hasSeparator;
+			catch (Exception e) assert(false, e.msg);
+		}
+		/// ditto
+		bool opEquals(string name)
+		const nothrow @nogc {
+			import std.utf : byCodeUnit;
+			try return equal(this.name, name.byCodeUnit);
+			catch (Exception e) assert(false, e.msg);
+		}
+	}
+
+	/** Represents a path as an forward range of `Segment2`s.
+
+		Note that in contrast to `PathRange`, this range allows pure `@nogc`
+		iteration over encoded path segments.
+	*/
+	static struct PathRange2 {
+		import std.traits : ReturnType;
+
+		private {
+			string m_path;
+			Segment2 m_front;
+		}
+
+		private this(string path)
+		{
+			m_path = path;
+			if (m_path.length) {
+				auto ap = Format.getAbsolutePrefix(m_path);
+				if (ap.length && !Format.isSeparator(ap[0]))
+					m_front = Segment2.fromTrustedEncodedString(null, '/');
+				else readFront();
+			}
+		}
+
+		@property bool empty() const nothrow @nogc { return m_path.length == 0 && m_front == Segment2.init; }
+
+		@property PathRange2 save() { return this; }
+
+		@property Segment2 front() { return m_front; }
+
+		void popFront()
+		nothrow {
+			assert(m_front != Segment2.init);
+			if (m_path.length) readFront();
+			else m_front = Segment2.init;
+		}
+
 		private void readFront()
 		{
 			auto n = Format.getFrontNode(m_path);
@@ -355,11 +549,12 @@ struct GenericPath(F) {
 				sep = n[$-1];
 				n = n[0 .. $-1];
 			}
-			m_front = Segment.fromTrustedString(Format.decodeSingleSegment(n), sep);
+			m_front = Segment2.fromTrustedEncodedString(n, sep);
-			assert(m_front != Segment.init);
+			assert(m_front != Segment2.init);
 		}
 	}
 
+
 	private {
 		string m_path;
 	}
@@ -390,6 +585,12 @@ struct GenericPath(F) {
 		import std.range : only;
 		this(only(segment));
 	}
+	/// ditto
+	this(Segment2 segment)
+	{
+		import std.range : only;
+		this(only(segment));
+	}
 
 	/** Constructs a path from an input range of `Segment`s.
 
@@ -405,6 +606,15 @@ struct GenericPath(F) {
 		Format.toString(segments, dst);
 		m_path = dst.data;
 	}
+	/// ditto
+	this(R)(R segments)
+		if (isInputRange!R && is(ElementType!R : Segment2))
+	{
+		import std.array : appender;
+		auto dst = appender!string;
+		Format.toString(segments, dst);
+		m_path = dst.data;
+	}
 
 	/** Constructs a path from its string representation.
 
@@ -451,16 +661,39 @@ struct GenericPath(F) {
 	/// Iterates over the path by `Segment`.
 	@property PathRange bySegment() const { return PathRange(m_path); }
 
+	/// Iterates over the path by `Segment`.
+	@property PathRange2 bySegment2() const { return PathRange2(m_path); }
+
 	/// Returns the trailing segment of the path.
 	@property Segment head()
 	const {
+		import std.array : array;
+
 		auto n = Format.getBackNode(m_path);
 		char sep = '\0';
 		if (n.length > 0 && Format.isSeparator(n[$-1])) {
 			sep = n[$-1];
 			n = n[0 .. $-1];
 		}
-		return Segment.fromTrustedString(Format.decodeSingleSegment(n), sep);
+
+		static if (is(typeof(Format.decodeSingleSegment(n)) == string))
+			string ndec = Format.decodeSingleSegment(n);
+		else
+			string ndec = Format.decodeSingleSegment(n).array;
+
+		return Segment.fromTrustedString(ndec, sep);
+	}
+
+	/// Returns the trailing segment of the path.
+	@property Segment2 head2()
+	const @nogc {
+		auto n = Format.getBackNode(m_path);
+		char sep = '\0';
+		if (n.length > 0 && Format.isSeparator(n[$-1])) {
+			sep = n[$-1];
+			n = n[0 .. $-1];
+		}
+		return Segment2.fromTrustedEncodedString(n, sep);
 	}
 
 	/** Determines if the `parentPath` property is valid.
@@ -580,8 +813,12 @@ struct GenericPath(F) {
 	/// ditto
 	GenericPath opBinary(string op : "~")(Segment subpath) const { return this ~ GenericPath(subpath); }
 	/// ditto
+	GenericPath opBinary(string op : "~")(Segment2 subpath) const { return this ~ GenericPath(subpath); }
+	/// ditto
 	GenericPath opBinary(string op : "~", F)(GenericPath!F.Segment subpath) const { return this ~ cast(Segment)(subpath); }
 	/// ditto
+	GenericPath opBinary(string op : "~", F)(GenericPath!F.Segment2 subpath) const { return this ~ cast(Segment2)(subpath); }
+	/// ditto
 	GenericPath opBinary(string op : "~")(GenericPath subpath) const nothrow {
 		assert(!subpath.absolute || m_path.length == 0, "Cannot append absolute path.");
 		if (endsWithSlash || empty) return GenericPath.fromTrustedString(m_path ~ subpath.m_path);
@@ -595,6 +832,12 @@ struct GenericPath(F) {
 	{
 		return this ~ GenericPath(entries);
 	}
+	/// ditto
+	GenericPath opBinary(string op : "~", R)(R entries) const nothrow
+		if (isInputRange!R && is(ElementType!R : Segment2))
+	{
+		return this ~ GenericPath(entries);
+	}
 
 	/// Appends a relative path to this path.
 	void opOpAssign(string op : "~", T)(T op) { this = this ~ op; }
@@ -610,8 +853,6 @@ struct GenericPath(F) {
 }
 
 unittest {
-	import std.algorithm.comparison : equal;
-
 	assert(PosixPath("hello/world").bySegment.equal([PosixPath.Segment("hello",'/'), PosixPath.Segment("world")]));
 	assert(PosixPath("/hello/world/").bySegment.equal([PosixPath.Segment("",'/'), PosixPath.Segment("hello",'/'), PosixPath.Segment("world",'/')]));
 	assert(PosixPath("hello\\world").bySegment.equal([PosixPath.Segment("hello\\world")]));
@@ -621,10 +862,18 @@ unittest {
 	assert(WindowsPath("hello/w\\orld").bySegment.equal([WindowsPath.Segment("hello",'/'), WindowsPath.Segment("w",'\\'), WindowsPath.Segment("orld")]));
 }
 
+unittest {
+	assert(PosixPath("hello/world").bySegment2.equal([PosixPath.Segment2("hello",'/'), PosixPath.Segment2("world")]));
+	assert(PosixPath("/hello/world/").bySegment2.equal([PosixPath.Segment2("",'/'), PosixPath.Segment2("hello",'/'), PosixPath.Segment2("world",'/')]));
+	assert(PosixPath("hello\\world").bySegment2.equal([PosixPath.Segment2("hello\\world")]));
+	assert(WindowsPath("hello/world").bySegment2.equal([WindowsPath.Segment2("hello",'/'), WindowsPath.Segment2("world")]));
+	assert(WindowsPath("/hello/world/").bySegment2.equal([WindowsPath.Segment2("",'/'), WindowsPath.Segment2("hello",'/'), WindowsPath.Segment2("world",'/')]));
+	assert(WindowsPath("hello\\w/orld").bySegment2.equal([WindowsPath.Segment2("hello",'\\'), WindowsPath.Segment2("w",'/'), WindowsPath.Segment2("orld")]));
+	assert(WindowsPath("hello/w\\orld").bySegment2.equal([WindowsPath.Segment2("hello",'/'), WindowsPath.Segment2("w",'\\'), WindowsPath.Segment2("orld")]));
+}
+
 unittest
 {
-	import std.algorithm.comparison : equal;
-
 	{
 		auto unc = "\\\\server\\share\\path";
 		auto uncp = WindowsPath(unc);
@@ -704,6 +953,55 @@ unittest
 	assert(PosixPath("foo/") ~ NativePath("bar") == PosixPath("foo/bar"));
 }
 
+unittest
+{
+	{
+		auto unc = "\\\\server\\share\\path";
+		auto uncp = WindowsPath(unc);
+		assert(uncp.absolute);
+		uncp.normalize();
+		version(Windows) assert(uncp.toNativeString() == unc);
+		assert(uncp.absolute);
+		assert(!uncp.endsWithSlash);
+	}
+
+	{
+		auto abspath = "/test/path/";
+		auto abspathp = PosixPath(abspath);
+		assert(abspathp.toString() == abspath);
+		version(Windows) {} else assert(abspathp.toNativeString() == abspath);
+		assert(abspathp.absolute);
+		assert(abspathp.endsWithSlash);
+		alias S = PosixPath.Segment2;
+		assert(abspathp.bySegment2.equal([S("", '/'), S("test", '/'), S("path", '/')]));
+	}
+
+	{
+		auto relpath = "test/path/";
+		auto relpathp = PosixPath(relpath);
+		assert(relpathp.toString() == relpath);
+		version(Windows) assert(relpathp.toNativeString() == "test/path/");
+		else assert(relpathp.toNativeString() == relpath);
+		assert(!relpathp.absolute);
+		assert(relpathp.endsWithSlash);
+		alias S = PosixPath.Segment2;
+		assert(relpathp.bySegment2.equal([S("test", '/'), S("path", '/')]));
+	}
+
+	{
+		auto winpath = "C:\\windows\\test";
+		auto winpathp = WindowsPath(winpath);
+		assert(winpathp.toString() == "C:\\windows\\test");
+		assert((cast(PosixPath)winpathp).toString() == "/C:/windows/test", (cast(PosixPath)winpathp).toString());
+		version(Windows) assert(winpathp.toNativeString() == winpath);
+		else assert(winpathp.toNativeString() == "/C:/windows/test");
+		assert(winpathp.absolute);
+		assert(!winpathp.endsWithSlash);
+		alias S = WindowsPath.Segment2;
+		assert(winpathp.bySegment2.equal([S("", '/'), S("C:", '\\'), S("windows", '\\'), S("test")]));
+	}
+}
+
 @safe unittest {
 	import std.array : appender;
 	auto app = appender!(PosixPath[]);
@@ -714,7 +1012,6 @@ unittest
 }
 
 unittest {
-	import std.algorithm.comparison : equal;
 	import std.exception : assertThrown, assertNotThrown;
 
 	assertThrown!PathValidationException(WindowsPath.Segment("foo/bar"));
@@ -727,6 +1024,20 @@ unittest {
 	assert(p.toString() == "/foo%2fbar/baz%2Fbam", p.toString);
 }
 
+unittest {
+	import std.exception : assertThrown, assertNotThrown;
+
+	assertThrown!PathValidationException(WindowsPath.Segment2("foo/bar"));
+	assertThrown!PathValidationException(PosixPath.Segment2("foo/bar"));
+	assertNotThrown!PathValidationException(InetPath.Segment2("foo/bar"));
+
+	auto p = InetPath("/foo%2fbar/");
+	import std.conv : to;
+	assert(p.bySegment2.equal([InetPath.Segment2("",'/'), InetPath.Segment2("foo/bar",'/')]), p.bySegment2.to!string);
+	p ~= InetPath.Segment2("baz/bam");
+	assert(p.toString() == "/foo%2fbar/baz%2Fbam", p.toString);
+}
+
 unittest {
 	assert(!PosixPath("").hasParentPath);
 	assert(!PosixPath("/").hasParentPath);
@@ -754,6 +1065,10 @@ unittest {
 	assert(WindowsPath([WindowsPath.Segment("foo"), WindowsPath.Segment("bar")]).toString() == "foo\\bar");
 }
 
+unittest {
+	assert(WindowsPath([WindowsPath.Segment2("foo"), WindowsPath.Segment2("bar")]).toString() == "foo\\bar");
+}
+
 /// Thrown when an invalid string representation of a path is detected.
 class PathValidationException : Exception {
 	this(string text, string file = __FILE__, size_t line = cast(size_t)__LINE__, Throwable next = null)
@@ -925,7 +1240,6 @@ struct WindowsPathFormat {
 	}
 
 	unittest {
-		import std.algorithm.comparison : equal;
 		struct Segment { string name; char separator = 0; static Segment fromTrustedString(string str, char sep = 0) pure nothrow @nogc { return Segment(str, sep); }}
 		assert(decodeSegment!Segment("foo").equal([Segment("foo")]));
 		assert(decodeSegment!Segment("foo/").equal([Segment("foo", '/')]));
@@ -935,13 +1249,12 @@ struct WindowsPathFormat {
 	}
 
 	static string decodeSingleSegment(string segment)
-	{
+	@nogc {
 		assert(segment.length == 0 || segment[$-1] != '/');
 		return segment;
 	}
 
 	unittest {
-		import std.algorithm.comparison : equal;
 		struct Segment { string name; char separator = 0; static Segment fromTrustedString(string str, char sep = 0) pure nothrow @nogc { return Segment(str, sep); }}
 		assert(decodeSingleSegment("foo") == "foo");
 		assert(decodeSingleSegment("fo%20o") == "fo%20o");
@@ -1002,8 +1315,7 @@ struct WindowsPathFormat {
 
 	static string encodeSegment(string segment)
 	{
-		assert(segment.length > 0, "Path segment string must not be empty.");
+		assert(segment.length == 0 || segment[$-1] != '/');
-		assert(segment[$-1] != '/');
 		return segment;
 	}
 }
@@ -1132,7 +1444,6 @@ struct PosixPathFormat {
 	}
 
 	unittest {
-		import std.algorithm.comparison : equal;
 		struct Segment { string name; char separator = 0; static Segment fromTrustedString(string str, char sep = 0) pure nothrow @nogc { return Segment(str, sep); }}
 		assert(decodeSegment!Segment("foo").equal([Segment("foo")]));
 		assert(decodeSegment!Segment("foo/").equal([Segment("foo", '/')]));
@@ -1140,13 +1451,12 @@ struct PosixPathFormat {
 	}
 
 	static string decodeSingleSegment(string segment)
-	{
+	@nogc {
 		assert(segment.length == 0 || segment[$-1] != '/');
 		return segment;
 	}
 
 	unittest {
-		import std.algorithm.comparison : equal;
 		struct Segment { string name; char separator = 0; static Segment fromTrustedString(string str, char sep = 0) pure nothrow @nogc { return Segment(str, sep); }}
 		assert(decodeSingleSegment("foo") == "foo");
 		assert(decodeSingleSegment("fo%20o\\") == "fo%20o\\");
@@ -1154,8 +1464,7 @@ struct PosixPathFormat {
 
 	static string encodeSegment(string segment)
 	{
-		assert(segment.length > 0, "Path segment string must not be empty.");
+		assert(segment.length == 0 || segment[$-1] != '/');
-		assert(segment[$-1] != '/');
 		return segment;
 	}
 }
@@ -1173,7 +1482,9 @@ struct InetPathFormat {
 		foreach (e; segments) {
 			if (!first || lastsep) dst.put('/');
 			else first = false;
-			encodeSegment(dst, e.name);
+			static if (is(typeof(e.encodedName)))
+				dst.put(e.encodedName);
+			else encodeSegment(dst, e.name);
 			lastsep = e.separator;
 		}
 		if (lastsep) dst.put('/');
@@ -1309,18 +1620,26 @@ struct InetPathFormat {
 	deprecated("Use decodeSingleSegment instead.")
 	static auto decodeSegment(S)(string segment)
 	{
+		import std.algorithm.searching : any;
+		import std.array : array;
+		import std.exception : assumeUnique;
 		import std.range : only;
+		import std.utf : byCodeUnit;
+
 		if (!segment.length) return only(S.fromTrustedString(null));
 		char sep = '\0';
 		if (segment[$-1] == '/') {
 			sep = '/';
 			segment = segment[0 .. $-1];
 		}
-		return only(S(decodeSingleSegment(segment), sep));
+
+		if (!segment.byCodeUnit.any!(c => c == '%'))
+			return only(S(segment, sep));
+		string n = decodeSingleSegment(segment).array;
+		return only(S(n, sep));
 	}
 
 	unittest {
-		import std.algorithm.comparison : equal;
 		struct Segment { string name; char separator = 0; static Segment fromTrustedString(string str, char sep = 0) pure nothrow @nogc { return Segment(str, sep); }}
 		assert(decodeSegment!Segment("foo").equal([Segment("foo")]));
 		assert(decodeSegment!Segment("foo/").equal([Segment("foo", '/')]));
@@ -1328,9 +1647,8 @@ struct InetPathFormat {
 		assert(decodeSegment!Segment("foo%20").equal([Segment("foo ")]));
 	}
 
-	static string decodeSingleSegment(string segment)
+	static auto decodeSingleSegment(string segment)
-	{
+	@nogc {
-		import std.array : appender;
 		import std.string : indexOf;
 
 		static int hexDigit(char ch) @safe nothrow @nogc {
@@ -1340,32 +1658,48 @@ struct InetPathFormat {
 			else return ch - 'A' + 10;
 		}
 
-		static string urlDecode(string s) @safe nothrow {
+		static struct R {
-			auto idx = s.indexOf('%');
+			@safe pure nothrow @nogc:
-			if (idx < 0) return s;
 
-			auto ret = appender!string;
+			private {
-			ret.put(s[0 .. idx]);
+				string m_str;
-
+				size_t m_index;
-			for (size_t i = idx; i < s.length; i++) {
-				if (s[i] == '%') {
-					assert(i+2 < s.length, "segment string not validated!?");
-					ret.put(cast(char)(hexDigit(s[i+1]) << 4 | hexDigit(s[i+2])));
-					i += 2;
-				} else ret.put(s[i]);
 			}
 
-			return ret.data;
+			this(string s)
+			{
+				m_str = s;
 			}
 
-		assert(segment.length == 0 || segment[$-1] != '/');
+			@property bool empty() const { return m_index >= m_str.length; }
-		return urlDecode(segment);
+
+			@property char front()
+			const {
+				auto ch = m_str[m_index];
+				if (ch != '%') return ch;
+
+				auto a = m_str[m_index+1];
+				auto b = m_str[m_index+2];
+				return cast(char)(16 * hexDigit(a) + hexDigit(b));
+			}
+
+			@property void popFront()
+			{
+				assert(!empty);
+				if (m_str[m_index] == '%') m_index += 3;
+				else m_index++;
+			}
+		}
+
+		return R(segment);
 	}
 
 	unittest {
-		assert(decodeSingleSegment("foo") == "foo");
+		scope (failure) assert(false);
-		assert(decodeSingleSegment("fo%20o\\") == "fo o\\");
+
-		assert(decodeSingleSegment("foo%20") == "foo ");
+		assert(decodeSingleSegment("foo").equal("foo"));
+		assert(decodeSingleSegment("fo%20o\\").equal("fo o\\"));
+		assert(decodeSingleSegment("foo%20").equal("foo "));
 	}
 
 
@@ -1424,4 +1758,5 @@ struct InetPathFormat {
 
 unittest { // regression tests
 	assert(NativePath("").bySegment.empty);
+	assert(NativePath("").bySegment2.empty);
 }