DocumentsStorageProvider: hash the accountName for rootId map

This should handle the fact that accountNames are of arbitrary length

MD5 is fine for this, as it should be quicker than SHA and the chance of collisions here is very low

Signed-off-by: Álvaro Brey <alvaro.brey@nextcloud.com>

app/src/main/java/com/nextcloud/client/utils/HashUtil.kt

@@ -0,0 +1,42 @@
+/*
+ *  Nextcloud Android Library is available under MIT license
+ *
+ *  @author Álvaro Brey Vilas
+ *  Copyright (C) 2022 Álvaro Brey Vilas
+ *  Copyright (C) 2022 Nextcloud GmbH
+ *
+ *  Permission is hereby granted, free of charge, to any person obtaining a copy
+ *  of this software and associated documentation files (the "Software"), to deal
+ *  in the Software without restriction, including without limitation the rights
+ *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ *  copies of the Software, and to permit persons to whom the Software is
+ *  furnished to do so, subject to the following conditions:
+ *
+ *  The above copyright notice and this permission notice shall be included in
+ *  all copies or substantial portions of the Software.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ *  BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ *  ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ *  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ *  THE SOFTWARE.
+ */
+
+package com.nextcloud.client.utils
+
+import org.apache.commons.codec.binary.Hex
+import java.security.MessageDigest
+
+object HashUtil {
+    private const val ALGORITHM_MD5 = "MD5"
+
+    @JvmStatic
+    fun md5Hash(input: String): String {
+        val digest = MessageDigest.getInstance(ALGORITHM_MD5)
+            .digest(input.toByteArray())
+        return String(Hex.encodeHex(digest))
+    }
+}

app/src/main/java/com/owncloud/android/providers/DocumentsStorageProvider.java

@@ -47,6 +47,7 @@ import com.nextcloud.client.account.UserAccountManager;
 import com.nextcloud.client.files.downloader.DownloadTask;
 import com.nextcloud.client.preferences.AppPreferences;
 import com.nextcloud.client.preferences.AppPreferencesImpl;
+import com.nextcloud.client.utils.HashUtil;
 import com.owncloud.android.MainApp;
 import com.owncloud.android.R;
 import com.owncloud.android.datamodel.FileDataStorageManager;
@@ -80,8 +81,6 @@ import org.nextcloud.providers.cursors.RootCursor;
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.IOException;
-import java.io.UnsupportedEncodingException;
-import java.net.URLEncoder;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
@@ -685,12 +684,7 @@ public class DocumentsStorageProvider extends DocumentsProvider {
     }
 
     private String rootIdForUser(User user) {
-        try {
-            return URLEncoder.encode(user.getAccountName(), "UTF-8");
-        } catch (UnsupportedEncodingException e) {
-            // this is a theoretical exception as UTF-8 is a standard required encoding
-            throw new IllegalStateException("UTF-8 encoding unavailable in this environment", e);
-        }
+        return HashUtil.md5Hash(user.getAccountName());
     }
 
     private void initiateStorageMap() {

app/src/test/java/com/nextcloud/client/utils/HashUtilTest.kt

@@ -0,0 +1,53 @@
+/*
+ *  Nextcloud Android Library is available under MIT license
+ *
+ *  @author Álvaro Brey Vilas
+ *  Copyright (C) 2022 Álvaro Brey Vilas
+ *  Copyright (C) 2022 Nextcloud GmbH
+ *
+ *  Permission is hereby granted, free of charge, to any person obtaining a copy
+ *  of this software and associated documentation files (the "Software"), to deal
+ *  in the Software without restriction, including without limitation the rights
+ *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ *  copies of the Software, and to permit persons to whom the Software is
+ *  furnished to do so, subject to the following conditions:
+ *
+ *  The above copyright notice and this permission notice shall be included in
+ *  all copies or substantial portions of the Software.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ *  BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ *  ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ *  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ *  THE SOFTWARE.
+ */
+
+package com.nextcloud.client.utils
+
+import org.junit.Assert
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.Parameterized
+
+@RunWith(Parameterized::class)
+class HashUtilTest(private val input: String, private val expected: String) {
+    companion object {
+        @JvmStatic
+        @Parameterized.Parameters(name = "{0}")
+        fun params(): List<Array<Any>> = listOf(
+            arrayOf("", "d41d8cd98f00b204e9800998ecf8427e"),
+            arrayOf("test", "098f6bcd4621d373cade4e832627b4f6"),
+            arrayOf("test@nextcloud.localhost", "12aa338095d171f307c3e3f724702ab1"),
+            arrayOf("tost@nextcloud.localhost", "e01e5301f90c123a65e872d68e84c4b2")
+        )
+    }
+
+    @Test
+    fun testMd5Hash() {
+        val hash = HashUtil.md5Hash(input)
+        Assert.assertEquals("Wrong hash for input", expected, hash)
+    }
+}