Use manifest URL sha1 hash as the content id.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=130293908

library/src/androidTest/java/com/google/android/exoplayer2/util/UtilTest.java

@@ -15,6 +15,7 @@
  */
  */
 package com.google.android.exoplayer2.util;
 package com.google.android.exoplayer2.util;
 
 
+import android.test.MoreAsserts;
 import com.google.android.exoplayer2.testutil.TestUtil;
 import com.google.android.exoplayer2.testutil.TestUtil;
 import java.text.ParseException;
 import java.text.ParseException;
 import java.util.ArrayList;
 import java.util.ArrayList;
@@ -145,6 +146,20 @@ public class UtilTest extends TestCase {
     assertEquals(1407322800000L, Util.parseXsDateTime("2014-08-06T11:00:00Z"));
     assertEquals(1407322800000L, Util.parseXsDateTime("2014-08-06T11:00:00Z"));
   }
   }
 
 
+  public void testGetHexStringByteArray() throws Exception {
+    assertHexStringByteArray("", new byte[] {});
+    assertHexStringByteArray("01", new byte[] {1});
+    assertHexStringByteArray("FF", new byte[] {(byte) 255});
+    assertHexStringByteArray("01020304", new byte[] {1, 2, 3, 4});
+    assertHexStringByteArray("0123456789ABCDEF",
+        new byte[] {1, 0x23, 0x45, 0x67, (byte) 0x89, (byte) 0xAB, (byte) 0xCD, (byte) 0xEF});
+  }
+
+  private void assertHexStringByteArray(String hex, byte[] array) {
+    assertEquals(hex, Util.getHexString(array));
+    MoreAsserts.assertEquals(array, Util.getBytesFromHexString(hex));
+  }
+
   public void testUnescapeInvalidFileName() {
   public void testUnescapeInvalidFileName() {
     assertNull(Util.unescapeFileName("%a"));
     assertNull(Util.unescapeFileName("%a"));
     assertNull(Util.unescapeFileName("%xyz"));
     assertNull(Util.unescapeFileName("%xyz"));

library/src/main/java/com/google/android/exoplayer2/source/dash/DashMediaSource.java

@@ -109,7 +109,7 @@ public final class DashMediaSource implements MediaSource {
     this.chunkSourceFactory = chunkSourceFactory;
     this.chunkSourceFactory = chunkSourceFactory;
     this.minLoadableRetryCount = minLoadableRetryCount;
     this.minLoadableRetryCount = minLoadableRetryCount;
     eventDispatcher = new EventDispatcher(eventHandler, eventListener);
     eventDispatcher = new EventDispatcher(eventHandler, eventListener);
-    manifestParser = new DashManifestParser();
+    manifestParser = new DashManifestParser(generateContentId());
     manifestCallback = new ManifestCallback();
     manifestCallback = new ManifestCallback();
     manifestUriLock = new Object();
     manifestUriLock = new Object();
     periodsById = new SparseArray<>();
     periodsById = new SparseArray<>();
@@ -441,6 +441,10 @@ public final class DashMediaSource implements MediaSource {
     }
     }
   }
   }
 
 
+  private String generateContentId() {
+    return Util.sha1(manifestUri.toString());
+  }
+
   private static final class PeriodSeekInfo {
   private static final class PeriodSeekInfo {
 
 
     public static PeriodSeekInfo createPeriodSeekInfo(Period period, long durationUs) {
     public static PeriodSeekInfo createPeriodSeekInfo(Period period, long durationUs) {

library/src/main/java/com/google/android/exoplayer2/util/Util.java

@@ -33,8 +33,11 @@ import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.io.OutputStream;
+import java.io.UnsupportedEncodingException;
 import java.math.BigDecimal;
 import java.math.BigDecimal;
 import java.nio.charset.Charset;
 import java.nio.charset.Charset;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
 import java.text.ParseException;
 import java.text.ParseException;
 import java.util.Arrays;
 import java.util.Arrays;
 import java.util.Calendar;
 import java.util.Calendar;
@@ -112,6 +115,8 @@ public final class Util {
 
 
   private static final Pattern ESCAPED_CHARACTER_PATTERN = Pattern.compile("%([A-Fa-f0-9]{2})");
   private static final Pattern ESCAPED_CHARACTER_PATTERN = Pattern.compile("%([A-Fa-f0-9]{2})");
 
 
+  private static final char[] HEX_DIGITS = "0123456789ABCDEF".toCharArray();
+
   private Util() {}
   private Util() {}
 
 
   /**
   /**
@@ -636,6 +641,17 @@ public final class Util {
     return data;
     return data;
   }
   }
 
 
+  /** Returns a hex string representation of the given byte array. */
+  public static String getHexString(byte[] bytes) {
+    char[] hexChars = new char[bytes.length * 2];
+    int i = 0;
+    for (byte v : bytes) {
+      hexChars[i++] = HEX_DIGITS[(v >> 4) & 0xf];
+      hexChars[i++] = HEX_DIGITS[v & 0xf];
+    }
+    return new String(hexChars);
+  }
+
   /**
   /**
    * Returns a string with comma delimited simple names of each object's class.
    * Returns a string with comma delimited simple names of each object's class.
    *
    *
@@ -839,4 +855,17 @@ public final class Util {
     }
     }
     return builder.toString();
     return builder.toString();
   }
   }
+
+  /** Returns the SHA-1 digest of input as a hex string. */
+  public static String sha1(String input) {
+    try {
+      MessageDigest digest = MessageDigest.getInstance("SHA-1");
+      byte[] bytes = input.getBytes("UTF-8");
+      digest.update(bytes, 0, bytes.length);
+      return getHexString(digest.digest());
+    } catch (NoSuchAlgorithmException | UnsupportedEncodingException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
 }
 }