fix dividing by zero while loading empty file (#26)

Author: danikula

library/src/main/java/com/danikula/videocache/HttpProxyCacheServer.java

@@ -91,7 +91,7 @@ private HttpProxyCacheServer(Config config) {
 
     private void makeSureServerWorks() {
         int maxPingAttempts = 3;
-        int delay = 200;
+        int delay = 300;
         int pingAttempts = 0;
         while (pingAttempts < maxPingAttempts) {
             try {
@@ -107,7 +107,7 @@ private void makeSureServerWorks() {
             pingAttempts++;
             delay *= 2;
         }
-        Log.e(LOG_TAG, "Shutdown server… Error pinging server [attempt: " + pingAttempts + ", timeout: " + delay + "]. " +
+        Log.e(LOG_TAG, "Shutdown server… Error pinging server [attempts: " + pingAttempts + ", max timeout: " + delay / 2 + "]. " +
                 "If you see this message, please, email me [email protected]");
         shutdown();
     }

library/src/main/java/com/danikula/videocache/ProxyCache.java

@@ -100,10 +100,11 @@ private void notifyNewCacheDataAvailable(long cacheAvailable, long sourceAvailab
         }
     }
 
-    protected void onCacheAvailable(long cacheAvailable, long sourceAvailable) {
-        int percents = (int) (cacheAvailable * 100 / sourceAvailable);
+    protected void onCacheAvailable(long cacheAvailable, long sourceLength) {
+        boolean zeroLengthSource = sourceLength == 0;
+        int percents = zeroLengthSource ? 100 : (int) (cacheAvailable * 100 / sourceLength);
         boolean percentsChanged = percents != percentsAvailable;
-        boolean sourceLengthKnown = sourceAvailable >= 0;
+        boolean sourceLengthKnown = sourceLength >= 0;
         if (sourceLengthKnown && percentsChanged) {
             onCachePercentsAvailableChanged(percents);
         }

test/src/test/java/com/danikula/videocache/HttpProxyCacheServerTest.java

@@ -211,9 +211,8 @@ public void testMaxFileCacheLimit() throws Exception {
     }
 
     private Pair<File, Response> readProxyData(String url, int offset) throws IOException {
-        File externalCacheDir = RuntimeEnvironment.application.getExternalCacheDir();
-        File file = file(externalCacheDir, url);
-        HttpProxyCacheServer proxy = newProxy(externalCacheDir);
+        File file = file(cacheFolder, url);
+        HttpProxyCacheServer proxy = newProxy(cacheFolder);
 
         Response response = readProxyResponse(proxy, url, offset);
         proxy.shutdown();

test/src/test/java/com/danikula/videocache/HttpProxyCacheTest.java

@@ -12,6 +12,7 @@
 import org.robolectric.annotation.Config;
 
 import java.io.ByteArrayOutputStream;
+import java.io.File;
 import java.net.Socket;
 
 import static com.danikula.videocache.support.ProxyCacheTestUtils.HTTP_DATA_URL;
@@ -20,6 +21,7 @@
 import static org.mockito.Matchers.any;
 import static org.mockito.Matchers.anyInt;
 import static org.mockito.Matchers.anyLong;
+import static org.mockito.Matchers.eq;
 import static org.mockito.Mockito.doThrow;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
@@ -73,4 +75,24 @@ public void testProcessPartialRequestWithoutCache() throws Exception {
         assertThat(response.data).isEqualTo(partialData);
         assertThat(response.code).isEqualTo(206);
     }
+
+    @Test
+    public void testLoadEmptyFile() throws Exception {
+        String zeroSizeUrl = "https://dl.dropboxusercontent.com/u/15506779/persistent/proxycache/empty.txt";
+        HttpUrlSource source = new HttpUrlSource(zeroSizeUrl);
+        HttpProxyCache proxyCache = new HttpProxyCache(source, new FileCache(ProxyCacheTestUtils.newCacheFile()));
+        GetRequest request = new GetRequest("GET /" + HTTP_DATA_URL + " HTTP/1.1");
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        Socket socket = mock(Socket.class);
+        when(socket.getOutputStream()).thenReturn(out);
+
+        CacheListener listener = Mockito.mock(CacheListener.class);
+        proxyCache.registerCacheListener(listener);
+        proxyCache.processRequest(request, socket);
+        proxyCache.registerCacheListener(null);
+        Response response = new Response(out.toByteArray());
+
+        Mockito.verify(listener).onCacheAvailable(Mockito.<File>any(), eq(zeroSizeUrl), eq(100));
+        assertThat(response.data).isEmpty();
+    }
 }

test/src/test/java/com/danikula/videocache/support/ProxyCacheTestUtils.java

@@ -40,7 +40,11 @@ public static Response readProxyResponse(HttpProxyCacheServer proxy, String url)
     }
 
     public static Response readProxyResponse(HttpProxyCacheServer proxy, String url, int offset) throws IOException {
-        URL proxiedUrl = new URL(proxy.getProxyUrl(url));
+        String proxyUrl = proxy.getProxyUrl(url);
+        if (!proxyUrl.startsWith("http://127.0.0.1")) {
+            throw new IllegalStateException("Url " + url + " is not proxied!");
+        }
+        URL proxiedUrl = new URL(proxyUrl);
         HttpURLConnection connection = (HttpURLConnection) proxiedUrl.openConnection();
         try {
             if (offset >= 0) {