diff --git a/src/fs/AllocatedPath.hxx b/src/fs/AllocatedPath.hxx
index 097217c7b..5988acb79 100644
--- a/src/fs/AllocatedPath.hxx
+++ b/src/fs/AllocatedPath.hxx
@@ -56,10 +56,6 @@ class AllocatedPath {
 	AllocatedPath(string &&_value) noexcept
 		:value(std::move(_value)) {}
 
-	static AllocatedPath Build(const_pointer a, size_t a_size,
-				   const_pointer b, size_t b_size) noexcept {
-		return AllocatedPath(Traits::Build(a, a_size, b, b_size));
-	}
 public:
 	/**
 	 * Construct a "nulled" instance.  Its IsNull() method will
@@ -93,14 +89,13 @@ public:
 	/**
 	 * Join two path components with the path separator.
 	 */
-	gcc_pure gcc_nonnull_all
-	static AllocatedPath Build(const_pointer a, const_pointer b) noexcept {
-		return Build(a, Traits::GetLength(a),
-			     b, Traits::GetLength(b));
+	gcc_pure
+	static AllocatedPath Build(string_view a, string_view b) noexcept {
+		return AllocatedPath(Traits::Build(a, b));
 	}
 
 	gcc_pure gcc_nonnull_all
-	static AllocatedPath Build(Path a, const_pointer b) noexcept {
+	static AllocatedPath Build(Path a, string_view b) noexcept {
 		return Build(a.c_str(), b);
 	}
 
@@ -110,24 +105,21 @@ public:
 	}
 
 	gcc_pure gcc_nonnull_all
-	static AllocatedPath Build(const_pointer a,
+	static AllocatedPath Build(string_view a,
 				   const AllocatedPath &b) noexcept {
-		return Build(a, Traits::GetLength(a),
-			     b.value.c_str(), b.value.size());
+		return Build(a, b.value);
 	}
 
 	gcc_pure gcc_nonnull_all
 	static AllocatedPath Build(const AllocatedPath &a,
-				   const_pointer b) noexcept {
-		return Build(a.value.c_str(), a.value.size(),
-			     b, Traits::GetLength(b));
+				   string_view b) noexcept {
+		return Build(a.value, b);
 	}
 
 	gcc_pure
 	static AllocatedPath Build(const AllocatedPath &a,
 				   const AllocatedPath &b) noexcept {
-		return Build(a.value.c_str(), a.value.size(),
-			     b.value.c_str(), b.value.size());
+		return Build(a.value, b.value);
 	}
 
 	gcc_pure
diff --git a/src/fs/Traits.cxx b/src/fs/Traits.cxx
index 25d0b48c6..555e6d72d 100644
--- a/src/fs/Traits.cxx
+++ b/src/fs/Traits.cxx
@@ -24,29 +24,26 @@
 
 template<typename Traits>
 typename Traits::string
-BuildPathImpl(typename Traits::const_pointer a, size_t a_size,
-	      typename Traits::const_pointer b, size_t b_size) noexcept
+BuildPathImpl(typename Traits::string_view a,
+	      typename Traits::string_view b) noexcept
 {
-	assert(a != nullptr);
-	assert(b != nullptr);
-
-	if (a_size == 0)
-		return typename Traits::string(b, b_size);
-	if (b_size == 0)
-		return typename Traits::string(a, a_size);
+	if (a.empty())
+		return typename Traits::string(b);
+	if (b.empty())
+		return typename Traits::string(a);
 
 	typename Traits::string result;
-	result.reserve(a_size + 1 + b_size);
+	result.reserve(a.length() + 1 + b.length());
 
-	result.append(a, a_size);
+	result.append(a);
 
-	if (!Traits::IsSeparator(a[a_size - 1]))
+	if (!Traits::IsSeparator(a.back()))
 		result.push_back(Traits::SEPARATOR);
 
-	if (Traits::IsSeparator(b[0]))
-		result.append(b + 1, b_size - 1);
+	if (Traits::IsSeparator(b.front()))
+		result.append(b.substr(1));
 	else
-		result.append(b, b_size);
+		result.append(b);
 
 	return result;
 }
@@ -122,10 +119,9 @@ RelativePathImpl(typename Traits::const_pointer base,
 }
 
 PathTraitsFS::string
-PathTraitsFS::Build(const_pointer a, size_t a_size,
-		    const_pointer b, size_t b_size) noexcept
+PathTraitsFS::Build(string_view a, string_view b) noexcept
 {
-	return BuildPathImpl<PathTraitsFS>(a, a_size, b, b_size);
+	return BuildPathImpl<PathTraitsFS>(a, b);
 }
 
 PathTraitsFS::const_pointer
@@ -161,10 +157,9 @@ PathTraitsFS::Apply(const_pointer base, const_pointer path) noexcept
 }
 
 PathTraitsUTF8::string
-PathTraitsUTF8::Build(const_pointer a, size_t a_size,
-		      const_pointer b, size_t b_size) noexcept
+PathTraitsUTF8::Build(string_view a, string_view b) noexcept
 {
-	return BuildPathImpl<PathTraitsUTF8>(a, a_size, b, b_size);
+	return BuildPathImpl<PathTraitsUTF8>(a, b);
 }
 
 PathTraitsUTF8::const_pointer
diff --git a/src/fs/Traits.hxx b/src/fs/Traits.hxx
index 72cdc0ba2..c604110bc 100644
--- a/src/fs/Traits.hxx
+++ b/src/fs/Traits.hxx
@@ -156,14 +156,8 @@ struct PathTraitsFS {
 	 * remaining component is returned unchanged.
 	 * If both components are empty strings, empty string is returned.
 	 */
-	gcc_pure gcc_nonnull_all
-	static string Build(const_pointer a, size_t a_size,
-			    const_pointer b, size_t b_size) noexcept;
-
-	gcc_pure gcc_nonnull_all
-	static string Build(const_pointer a, const_pointer b) noexcept {
-		return Build(a, GetLength(a), b, GetLength(b));
-	}
+	gcc_pure
+	static string Build(string_view a, string_view b) noexcept;
 
 	/**
 	 * Interpret the given path as being relative to the given
@@ -271,14 +265,8 @@ struct PathTraitsUTF8 {
 	 * remaining component is returned unchanged.
 	 * If both components are empty strings, empty string is returned.
 	 */
-	gcc_pure gcc_nonnull_all
-	static string Build(const_pointer a, size_t a_size,
-			    const_pointer b, size_t b_size) noexcept;
-
-	gcc_pure gcc_nonnull_all
-	static string Build(const_pointer a, const_pointer b) noexcept {
-		return Build(a, GetLength(a), b, GetLength(b));
-	}
+	gcc_pure
+	static string Build(string_view a, string_view b) noexcept;
 };
 
 #endif