Add file utility:

* ToAbsolutePath method added; not very well tested, since I don't know the environment the code will run on and the test code would be to prone to errors.

util/files/files.go

@@ -0,0 +1,43 @@
+package files
+
+import (
+	"net/url"
+	"os/user"
+	"path/filepath"
+	"strings"
+)
+
+// ToAbsolutePath handles different kind of paths and makes an absolute path
+// out of them. Consider the following three inputs:
+// 	   file:///home/marcel/test.txt%C3%A4
+//     ./test.txtä
+//     ~/test.txtä
+// Those will be turned into  (assuming that our current working directory
+// is /home/marcel:
+//     /home/marcel/test.txtä
+// However, this method doesn't check for file existence.
+func ToAbsolutePath(input string) (string, error) {
+	var resolvedPath string
+	if strings.HasPrefix(input, "~") {
+		currentUser, userResolveError := user.Current()
+		if userResolveError != nil {
+			return "", userResolveError
+		}
+
+		resolvedPath = filepath.Join(currentUser.HomeDir, strings.TrimPrefix(input, "~"))
+	} else {
+		resolvedPath = strings.TrimPrefix(input, "file://")
+		var unescapeError error
+		resolvedPath, unescapeError = url.PathUnescape(resolvedPath)
+		if unescapeError != nil {
+			return "", unescapeError
+		}
+	}
+
+	resolvedPath, resolveError := filepath.Abs(resolvedPath)
+	if resolveError != nil {
+		return "", resolveError
+	}
+
+	return resolvedPath, nil
+}

util/files/files_test.go

@@ -0,0 +1,45 @@
+//+build !windows
+
+package files
+
+import (
+	"testing"
+)
+
+func TestToAbsolutePath(t *testing.T) {
+	tests := []struct {
+		name    string
+		input   string
+		want    string
+		wantErr bool
+	}{
+		{
+			name:    "absolute path",
+			input:   "/test.txt",
+			want:    "/test.txt",
+			wantErr: false,
+		}, {
+			name:    "absolute path; file uri",
+			input:   "file:///te%20st.txt",
+			want:   "/te st.txt",
+			wantErr: false,
+		}, {
+			name:    "absolute path; contains Escaped characters",
+			input:   "/te%20st.txt",
+			want:   "/te st.txt",
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := ToAbsolutePath(tt.input)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("ToAbsolutePath() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if got != tt.want {
+				t.Errorf("ToAbsolutePath() got = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

util/files/files_windows_test.go

@@ -0,0 +1,43 @@
+package files
+
+import (
+	"testing"
+)
+
+func TestToAbsolutePath(t *testing.T) {
+	tests := []struct {
+		name    string
+		input   string
+		want    string
+		wantErr bool
+	}{
+		{
+			name:    "absolute path",
+			input:   "C:/test.txt",
+			want:    "C:/test.txt",
+			wantErr: false,
+		}, {
+			name:    "absolute path; file uri",
+			input:   "file://C:/te%20st.txt",
+			want:    "C:/te st.txt",
+			wantErr: false,
+		}, {
+			name:    "absolute path; contains Escaped characters",
+			input:   "C:/te%20st.txt",
+			want:    "C:/te st.txt",
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := ToAbsolutePath(tt.input)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("ToAbsolutePath() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if got != tt.want {
+				t.Errorf("ToAbsolutePath() got = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}