Tackle some Windows issues, again

Author: fzhinkin

core/common/test/files/SmokeFileTest.kt

@@ -168,7 +168,6 @@ class SmokeFileTest {
     @Test
     fun trailingSeparatorsTrimming() {
         assertEquals(Path(".").toString(), Path(".///").toString())
-        assertEquals(Path("/").toString(), Path("///").toString())
         assertEquals(Path("/").toString(), Path("/").toString())
         assertEquals(Path("/..").toString(), Path("/../").toString())
         assertEquals(Path("/a/b/c").toString(), Path("/a/b/c").toString())

core/js/src/files/PathsJs.kt

@@ -156,10 +156,27 @@ internal class FileSink(private val path: Path, private var append: Boolean) : R
     }
 }
 
+private fun isUnc(path: String): Boolean {
+    if (path.length < 2) return false
+    if (path.startsWith("$WindowsPathSeparator$WindowsPathSeparator")) return true
+    if (path.startsWith("$UnixPathSeparator$UnixPathSeparator")) return true
+    return false
+}
+
 internal fun removeTrailingSeparators(path: String): String {
     if (isWindows) {
         // don't trim the path separator right after the drive name
-        val limit = if (path.length > 1 && path[1] == ':') 3 else 1
+        val limit = if (path.length > 1) {
+            if (path[1] == ':') {
+                3
+            } else if (isUnc(path)) {
+                2
+            } else {
+                1
+            }
+        } else {
+            1
+        }
         return removeTrailingSeparators(limit, path, UnixPathSeparator, WindowsPathSeparator)
     }
     return removeTrailingSeparators(path, SystemPathSeparator)

core/mingw/src/files/FileSystemMingw.kt

@@ -58,10 +58,23 @@ internal actual fun realpathImpl(path: String): String {
     }
 }
 
+private fun isUnc(path: String): Boolean {
+    if (path.length < 2) return false
+    if (path.startsWith("$WindowsPathSeparator$WindowsPathSeparator")) return true
+    if (path.startsWith("$SystemPathSeparator$SystemPathSeparator")) return true
+    return false
+}
+
 internal actual fun removeTrailingSeparators(path: String): String {
     // Don't trim path separator following the drive name
-    val limit = if (path.length > 1 && path[1] == ':') {
-        3
+    val limit = if (path.length > 1) {
+        if (path[1] == ':') {
+            3
+        } else if (isUnc(path)) {
+            2
+        } else {
+            1
+        }
     } else {
         1
     }

core/mingw/test/files/SmokeFileTestWindows.kt

@@ -33,6 +33,8 @@ class SmokeFileTestWindows {
         assertEquals(".", Path(".\\").toString())
         assertEquals("C:\\", Path("C:\\").toString())
         assertEquals("C:\\", Path("C:\\\\").toString())
+        assertEquals("\\\\", Path("\\\\").toString())
+        assertEquals("//", Path("//").toString())
         assertEquals(".\\a", Path(".\\a\\//\\//\\\\////").toString())
     }
 }