From 3ac3efe92c892e7144a7490bcc11d5cdfea54898 Mon Sep 17 00:00:00 2001
From: Edontin <1924446+Edontin@users.noreply.github.com>
Date: Sat, 22 Feb 2020 18:47:01 +1000
Subject: [PATCH] Fix playlist path resolution for symlinked paths. (#1016)

Change path resolution to remove parent directories without following
symbolic links.

When resolving relative paths such as `../../storage/emulated/0/`
the symlinks will be read and parent paths removed, in that order.
This results in paths from an `/sdcard` symlink producing unexpected
relative paths e.g.`/sdcard/../storage/emulated/0/test.mp3` resolves to
`/storage/emulated/storage/emulated/0/test.mp3` instead of
`/storage/emulated/0/test.mp3`.
---
 .../android/vanilla/FileUtils.java            | 26 ++++++++++++++++---
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/app/src/main/java/ch/blinkenlights/android/vanilla/FileUtils.java b/app/src/main/java/ch/blinkenlights/android/vanilla/FileUtils.java
index a6812bb5..c2cf644f 100644
--- a/app/src/main/java/ch/blinkenlights/android/vanilla/FileUtils.java
+++ b/app/src/main/java/ch/blinkenlights/android/vanilla/FileUtils.java
@@ -20,10 +20,11 @@ package ch.blinkenlights.android.vanilla;
 import ch.blinkenlights.android.medialibrary.MediaLibrary;
 
 import java.io.File;
-import java.io.IOException;
 import java.net.URI;
 import java.net.URLConnection;
 import java.net.URISyntaxException;
+import java.util.ArrayList;
+import java.util.StringTokenizer;
 
 import android.content.Context;
 import android.content.Intent;
@@ -31,6 +32,7 @@ import android.content.SharedPreferences;
 import android.net.Uri;
 import android.os.Build;
 import android.os.Environment;
+import android.text.TextUtils;
 import android.util.Log;
 
 
@@ -144,12 +146,28 @@ public class FileUtils {
 
 		try {
 			if (!destination.isAbsolute()) {
-				path = new File(base, path).getCanonicalPath();
+				path = new File(base, path).getAbsolutePath();
+				final ArrayList<String> pathComponents = new ArrayList<>();
+				final StringTokenizer pathTokenizer = new StringTokenizer(path, File.separator);
+
+				while (pathTokenizer.hasMoreTokens()) {
+					final String pathComponent = pathTokenizer.nextToken();
+
+					if (NAME_PARENT_FOLDER.equals(pathComponent)) {
+						final int lastComponentPosition = pathComponents.size() - 1;
+
+						if (lastComponentPosition >= 0
+							&& !NAME_PARENT_FOLDER.equals(pathComponents.get(lastComponentPosition))) {
+							pathComponents.remove(lastComponentPosition);
+						}
+					} else {
+						pathComponents.add(pathComponent);
+					}
+				}
+				path = File.separator + TextUtils.join(File.separator, pathComponents);
 			}
 		} catch (SecurityException ex) {
 			// Ignore.
-		}catch (IOException ex){
-			// Ignore
 		}
 		return path;
 	}