Fix issue with reference code lens not working with UNC paths (PowerShell#908)

* Fix issue with reference code lens not working with UNC paths

* Refactor to avoid extra Insert ops. Simplifies macOS/Linux code path.

* Still need to unescape / on macOs & Linux

* Replace compile-time check for .NET Core with runtime check

Author: rkeithhill

src/PowerShellEditorServices/Workspace/Workspace.cs

@@ -639,7 +639,7 @@ private static string UnescapeDriveColon(string fileUri)
         /// <returns>The file system path encoded as a DocumentUri.</returns>
         public static string ConvertPathToDocumentUri(string path)
         {
-            const string fileUriPrefix = "file:///";
+            const string fileUriPrefix = "file:";
             const string untitledUriPrefix = "untitled:";
 
             // If path is already in document uri form, there is nothing to convert.
@@ -650,42 +650,78 @@ public static string ConvertPathToDocumentUri(string path)
             }
 
             string escapedPath = Uri.EscapeDataString(path);
-            var docUriStrBld = new StringBuilder(escapedPath);
+
+            // Max capacity of the StringBuilder will be the current escapedPath length
+            // plus extra chars for file:///.
+            var docUriStrBld = new StringBuilder(escapedPath.Length + fileUriPrefix.Length + 3);
+            docUriStrBld.Append(fileUriPrefix).Append("//");
 
             if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
             {
-                // VSCode file URIs on Windows need the drive letter lowercase.
-                // Search original path for colon since a char search (no string culture involved)
-                // is faster than a string search.
+                // VSCode file URIs on Windows need the drive letter to be lowercase. Search the
+                // original path for colon since a char search (no string culture involved) is
+                // faster than a string search.  If found, then lowercase the associated drive letter.
                 if (path.Contains(':'))
                 {
-                    // Start at index 1 to avoid an index out of range check when accessing index - 1.
-                    // Also, if the colon is at index 0 there is no drive letter before it to lower case.
-                    for (int i = 1; i < docUriStrBld.Length - 2; i++)
+                    // A valid, drive-letter based path converted to URI form needs to be prefixed
+                    // with a / to indicate the path is an absolute path.
+                    docUriStrBld.Append("/");
+                    int prefixLen = docUriStrBld.Length;
+
+                    docUriStrBld.Append(escapedPath);
+
+                    // Uri.EscapeDataString goes a bit far, encoding \ chars. Also, VSCode wants / instead of \.
+                    docUriStrBld.Replace("%5C", "/");
+
+                    // Find the first colon after the "file:///" prefix, skipping the first char after
+                    // the prefix since a Windows path cannot start with a colon. End the check at
+                    // less than docUriStrBld.Length - 2 since we need to look-ahead two characters.
+                    for (int i = prefixLen + 1; i < docUriStrBld.Length - 2; i++)
                     {
                         if ((docUriStrBld[i] == '%') && (docUriStrBld[i + 1] == '3') && (docUriStrBld[i + 2] == 'A'))
                         {
                             int driveLetterIndex = i - 1;
                             char driveLetter = char.ToLowerInvariant(docUriStrBld[driveLetterIndex]);
-                            docUriStrBld.Replace(path[driveLetterIndex], driveLetter, driveLetterIndex, 1);
+                            docUriStrBld.Replace(docUriStrBld[driveLetterIndex], driveLetter, driveLetterIndex, 1);
                             break;
                         }
                     }
                 }
+                else
+                {
+                    // This is a Windows path without a drive specifier, must be either a relative or UNC path.
+                    int prefixLen = docUriStrBld.Length;
+
+                    docUriStrBld.Append(escapedPath);
+
+                    // Uri.EscapeDataString goes a bit far, encoding \ chars. Also, VSCode wants / instead of \.
+                    docUriStrBld.Replace("%5C", "/");
 
-                // Uri.EscapeDataString goes a bit far, encoding \ chars. Also, VSCode wants / instead of \.
-                docUriStrBld.Replace("%5C", "/");
+                    // The proper URI form for a UNC path is file://server/share.  In the case of a UNC
+                    // path, remove the path's leading // because the file:// prefix already provides it.
+                    if ((docUriStrBld.Length > prefixLen + 1) &&
+                        (docUriStrBld[prefixLen] == '/') &&
+                        (docUriStrBld[prefixLen + 1] == '/'))
+                    {
+                        docUriStrBld.Remove(prefixLen, 2);
+                    }
+                }
             }
             else
             {
-                // Because we will prefix later with file:///, remove the initial encoded / if this is an absolute path.
-                // See https://docs.microsoft.com/en-us/dotnet/api/system.uri?view=netframework-4.7.2#implicit-file-path-support
-                // Uri.EscapeDataString goes a bit far, encoding / chars.
-                docUriStrBld.Replace("%2F", string.Empty, 0, 3).Replace("%2F", "/");
+                // On non-Windows systems, append the escapedPath and undo the over-aggressive
+                // escaping of / done by Uri.EscapeDataString.
+                docUriStrBld.Append(escapedPath).Replace("%2F", "/");
+            }
+
+            if (!Utils.IsNetCore)
+            {
+                // ' is not encoded by Uri.EscapeDataString in Windows PowerShell 5.x.
+                // This is apparently a difference between .NET Framework and .NET Core.
+                docUriStrBld.Replace("'", "%27");
             }
 
-            // ' is not always encoded.  I've seen this in Windows PowerShell.
-            return docUriStrBld.Replace("'", "%27").Insert(0, fileUriPrefix).ToString();
+            return docUriStrBld.ToString();
         }
 
         #endregion

test/PowerShellEditorServices.Test/Session/ScriptFileTests.cs

@@ -593,9 +593,14 @@ public void DocumentUriRetunsCorrectStringForAbsolutePath()
                 scriptFile = new ScriptFile(path, path, emptyStringReader, PowerShellVersion);
                 Assert.Equal("file:///c%3A/Users/AmosBurton/projects/Rocinate/ProtoMolecule.ps1", scriptFile.DocumentUri);
 
-                path = @"c:\Users\BobbyDraper\projects\Rocinate\foo's_~#-[@] +,;=%.ps1";
+                path = @"c:\Users\BobbieDraper\projects\Rocinate\foo's_~#-[@] +,;=%.ps1";
                 scriptFile = new ScriptFile(path, path, emptyStringReader, PowerShellVersion);
-                Assert.Equal("file:///c%3A/Users/BobbyDraper/projects/Rocinate/foo%27s_~%23-%5B%40%5D%20%2B%2C%3B%3D%25.ps1", scriptFile.DocumentUri);
+                Assert.Equal("file:///c%3A/Users/BobbieDraper/projects/Rocinate/foo%27s_~%23-%5B%40%5D%20%2B%2C%3B%3D%25.ps1", scriptFile.DocumentUri);
+
+                // Test UNC path
+                path = @"\\ClarissaMao\projects\Rocinate\foo's_~#-[@] +,;=%.ps1";
+                scriptFile = new ScriptFile(path, path, emptyStringReader, PowerShellVersion);
+                Assert.Equal("file://ClarissaMao/projects/Rocinate/foo%27s_~%23-%5B%40%5D%20%2B%2C%3B%3D%25.ps1", scriptFile.DocumentUri);
             }
             else
             {
@@ -604,9 +609,9 @@ public void DocumentUriRetunsCorrectStringForAbsolutePath()
                 scriptFile = new ScriptFile(path, path, emptyStringReader, PowerShellVersion);
                 Assert.Equal("file:///home/AlexKamal/projects/Rocinate/ProtoMolecule.ps1", scriptFile.DocumentUri);
 
-                path = "/home/BobbyDraper/projects/Rocinate/foo's_~#-[@] +,;=%.ps1";
+                path = "/home/BobbieDraper/projects/Rocinate/foo's_~#-[@] +,;=%.ps1";
                 scriptFile = new ScriptFile(path, path, emptyStringReader, PowerShellVersion);
-                Assert.Equal("file:///home/BobbyDraper/projects/Rocinate/foo%27s_~%23-%5B%40%5D%20%2B%2C%3B%3D%25.ps1", scriptFile.DocumentUri);
+                Assert.Equal("file:///home/BobbieDraper/projects/Rocinate/foo%27s_~%23-%5B%40%5D%20%2B%2C%3B%3D%25.ps1", scriptFile.DocumentUri);
 
                 path = "/home/NaomiNagata/projects/Rocinate/Proto:Mole:cule.ps1";
                 scriptFile = new ScriptFile(path, path, emptyStringReader, PowerShellVersion);