Opa should be capable of accessing Rego policies from the following i…

…nput sources:

Existing Inputs:
1. Absolute file paths (e.g., /a/b/c/example.rego)
2. Paths with URLs (e.g., file:///path/to/file.json)
3. Paths with drive letters and URLs (e.g., "C:file:///C:/a/b/c")

New Inputs:
1. Paths with drive letters (e.g., C:\a\b\c\example.rego)

This requirement ensures that Opa can handle a variety of input formats, including local file paths, remote URLs, and even mixed formats that include both drive letters and URLs.

open-policy-agent#6910
Signed-off-by: pckvcode <[email protected]>

loader/loader.go

@@ -572,8 +572,10 @@ func SplitPrefix(path string) ([]string, string) {
 		return nil, path
 	}
 	parts := strings.SplitN(path, ":", 2)
-	if len(parts) == 2 && len(parts[0]) > 1 {
-		return strings.Split(parts[0], "."), parts[1]
+	if len(parts) == 2 && len(parts[0]) > 0 {
+		if strings.HasPrefix(parts[1], "file:///") || len(parts[0]) > 1 {
+			return strings.Split(parts[0], "."), parts[1]
+		}
 	}
 	return nil, path
 }

loader/loader_test.go

@@ -827,6 +827,11 @@ func TestSplitPrefix(t *testing.T) {
 			input:    "c:/a/b/c",
 			wantPath: "c:/a/b/c",
 		},
+		{
+			input:     "c:file:///c:/a/b/c",
+			wantParts: []string{"c"},
+			wantPath:  "file:///c:/a/b/c",
+		},
 	}
 
 	for _, tc := range tests {