fix: URL path encoding on Windows: C: -> c%3A

uri.go

@@ -11,6 +11,8 @@ import (
 	"net/url"
 	"path/filepath"
 	"regexp"
+	"strings"
+	"unicode"
 
 	"github.com/arduino/go-paths-helper"
 	"go.bug.st/json"
@@ -29,7 +31,11 @@ type DocumentURI struct {
 // NilURI is the empty DocumentURI
 var NilURI = DocumentURI{}
 
-var expDriveID = regexp.MustCompile("^/[a-zA-Z]:")
+// for example, `"/c:"` or `"/A:"`
+var expDriveWithLeadingSlashID = regexp.MustCompile("^/[a-zA-Z]:")
+
+// for example, `"C:"` or `"A:"`
+var expUppercaseDriveID = regexp.MustCompile("^[A-Z]:")
 
 // AsPath convert the DocumentURI to a paths.Path
 func (uri DocumentURI) AsPath() *paths.Path {
@@ -39,12 +45,23 @@ func (uri DocumentURI) AsPath() *paths.Path {
 // unbox convert the DocumentURI to a file path string
 func (uri DocumentURI) unbox() string {
 	path := uri.url.Path
-	if expDriveID.MatchString(path) {
+	if expDriveWithLeadingSlashID.MatchString(path) {
 		return path[1:]
 	}
 	return path
 }
 
+// Converts `"C:"` to `"c:"` to be compatible with VS Code URI's drive letter casing
+// https://github.com/Microsoft/vscode/issues/68325#issuecomment-462239992
+func lowercaseDriveSegment(pathSegment string) string {
+	if expUppercaseDriveID.MatchString(pathSegment) {
+		chars := []rune(pathSegment)
+		chars[0] = unicode.ToLower(chars[0])
+		return string(chars)
+	}
+	return pathSegment
+}
+
 func (uri DocumentURI) String() string {
 	return uri.url.String()
 }
@@ -68,11 +85,23 @@ func NewDocumentURI(path string) DocumentURI {
 	if len(path) == 0 || path[0] != '/' {
 		path = "/" + path
 	}
-	uri, err := NewDocumentURIFromURL("file://")
+	segments := strings.Split(path, "/")
+	encodedSegments := make([]string, len(segments))
+	for i, segment := range segments {
+		if len(segment) == 0 {
+			encodedSegments[i] = segment
+		} else {
+			segment = lowercaseDriveSegment(segment)
+			segment = url.QueryEscape(segment)
+			// Spaces must be turned into `%20`. Otherwise, `url.QueryEscape`` encodes them to `+`.
+			encodedSegments[i] = strings.ReplaceAll(segment, "+", "%20")
+		}
+	}
+	urlPath := strings.Join(encodedSegments, "/")
+	uri, err := NewDocumentURIFromURL("file://" + urlPath)
 	if err != nil {
 		panic(err)
 	}
-	uri.url.Path = path
 	return uri
 }
 
@@ -89,7 +118,7 @@ func NewDocumentURIFromURL(inURL string) (DocumentURI, error) {
 func (uri *DocumentURI) UnmarshalJSON(data []byte) error {
 	var s string
 	if err := json.Unmarshal(data, &s); err != nil {
-		return fmt.Errorf("expoected JSON string for DocumentURI: %s", err)
+		return fmt.Errorf("expected JSON string for DocumentURI: %s", err)
 	}
 
 	newDocURI, err := NewDocumentURIFromURL(s)

uri_test.go

@@ -48,7 +48,9 @@ func TestPathToUri(t *testing.T) {
 	toSlash = windowsToSlash // Emulate windows cases
 
 	d = NewDocumentURI("C:\\Users\\test\\Sketch.ino")
-	require.Equal(t, "file:///C:/Users/test/Sketch.ino", d.String())
+	require.Equal(t, "file:///c%3A/Users/test/Sketch.ino", d.String()) // driver letter is converted to lower case https://github.com/Microsoft/vscode/issues/68325#issuecomment-462239992
+	d = NewDocumentURI("c:\\Users\\test\\Sketch.ino")
+	require.Equal(t, "file:///c%3A/Users/test/Sketch.ino", d.String())
 	d = NewDocumentURI("/Users/test/Sketch.ino")
 	require.Equal(t, "file:///Users/test/Sketch.ino", d.String())
 	d = NewDocumentURI("\U0001F61B")
@@ -70,7 +72,7 @@ func TestJSONMarshalUnmarshal(t *testing.T) {
 	d = NewDocumentURI("C:\\Users\\test\\Sketch.ino")
 	data, err := json.Marshal(d)
 	require.NoError(t, err)
-	require.Equal(t, `"file:///C:/Users/test/Sketch.ino"`, string(data))
+	require.Equal(t, `"file:///c%3A/Users/test/Sketch.ino"`, string(data))
 
 	d = NewDocumentURI("/Users/test/Sketch.ino")
 	data, err = json.Marshal(d)