2385 Only allow very limited set of characters in file names

app/src/androidTest/java/de/test/antennapod/util/FilenameGeneratorTest.java

@@ -34,6 +34,16 @@ public class FilenameGeneratorTest extends AndroidTestCase {
 		createFiles(result);
 	}
 
+	public void testFeedTitleContainsApostrophe() {
+		String result = FileNameGenerator.generateFileName("Feed's Title ...");
+		assertEquals("Feeds Title", result);
+	}
+
+	public void testFeedTitleContainsDash() {
+		String result = FileNameGenerator.generateFileName("Left - Right");
+		assertEquals("Left Right", result);
+	}
+
 	/**
 	 * Tests if files can be created.
 	 * 

core/src/main/java/de/danoeh/antennapod/core/storage/DownloadRequester.java

@@ -345,9 +345,7 @@ public class DownloadRequester {
         // Try to generate the filename by the item title
         if (media.getItem() != null && media.getItem().getTitle() != null) {
             String title = media.getItem().getTitle();
-            // Delete reserved characters
-            titleBaseFilename = title.replaceAll("[^a-zA-Z0-9 ._()-]", "");
-            titleBaseFilename = titleBaseFilename.trim();
+            titleBaseFilename = FileNameGenerator.generateFileName(title);
         }
 
         String URLBaseFilename = URLUtil.guessFileName(media.getDownload_url(),

core/src/main/java/de/danoeh/antennapod/core/util/FileNameGenerator.java

@@ -1,18 +1,21 @@
 package de.danoeh.antennapod.core.util;
 
+import org.apache.commons.lang3.ArrayUtils;
+
 import java.util.Arrays;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 /** Generates valid filenames for a given string. */
 public class FileNameGenerator {
 	
-	private static final char[] ILLEGAL_CHARACTERS = { '/', '\\', '?', '%',
-			'*', ':', '|', '"', '<', '>', '\n' };
-	static {
-		Arrays.sort(ILLEGAL_CHARACTERS);
-	}
+	private static final char[] validChars = (
+			"abcdefghijklmnopqrstuvwxyz" +
+			"ABCDEFGHIJKLMNOPQRSTUVWXYZ" +
+			"0123456789" +
+			" _-").toCharArray();
 	
 	private FileNameGenerator() {
-
 	}
 
 	/**
@@ -20,17 +23,17 @@ public class FileNameGenerator {
 	 * characters of the given string.
 	 */
 	public static String generateFileName(String string) {
-		StringBuilder builder = new StringBuilder();
+		StringBuilder buf = new StringBuilder();
 		for (int i = 0; i < string.length(); i++) {
 			char c = string.charAt(i);
-			if (Arrays.binarySearch(ILLEGAL_CHARACTERS, c) < 0) {
-				builder.append(c);
+			if(Character.isSpaceChar(c) && (buf.length() == 0 || Character.isSpaceChar(buf.charAt(buf.length()-1)))) {
+				continue;
+			}
+			if (ArrayUtils.contains(validChars, c)) {
+				buf.append(c);
 			}
 		}
-		return builder.toString().replaceFirst("  *$","");
+		return buf.toString().trim();
 	}
 
-	public static long generateLong(final String str) {
-		return str.hashCode();
-	}
 }