Noissue - Lint adjustments and optimizations

adblockplussbrowser/src/org/adblockplus/sbrowser/contentblocker/engine/Subscription.java

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 26 matching lines @@
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.zip.GZIPInputStream;
 import java.util.zip.GZIPOutputStream;
 
 import android.text.TextUtils;
+import android.text.format.DateUtils;
 import android.util.Log;
 
 /**
  * Simple subscription representation.
  */
 final class Subscription
 {
   private static final String TAG = Subscription.class.getSimpleName();
   public static final String KEY_TITLE = "title";
   public static final String KEY_VERSION = "version";
   public static final String KEY_FORCED_TITLE = "_title";
   public static final String KEY_HTTP_ETAG = "_etag";
   public static final String KEY_HTTP_LAST_MODIFIED = "_last_modified";
   public static final String KEY_UPDATE_TIMESTAMP = "_update_timestamp";
   public static final String KEY_TRIED_UPDATE_TIMESTAMP = "_tried_update_timestamp";
   public static final String KEY_DOWNLOAD_COUNT = "_download_count";
   public static final String KEY_ENABLED = "_enabled";
   public static final String KEY_HAS_FILTERS = "_has_filters";
   public static final String KEY_META_HASH = "_meta_hash";
 
-  public static final long MINIMAL_DOWNLOAD_INTERVAL = Engine.MILLIS_PER_HOUR / 4;
-  public static final long DOWNLOAD_RETRY_INTERVAL = Engine.MILLIS_PER_HOUR;
+  private static final long MINIMAL_DOWNLOAD_INTERVAL = DateUtils.HOUR_IN_MILLIS / 4;
+  private static final long DOWNLOAD_RETRY_INTERVAL = DateUtils.HOUR_IN_MILLIS;
 
   private static final HashSet<String> ALLOWED_META_KEYS = new HashSet<>();
   private static final Locale LOCALE_EN = Locale.ENGLISH;
 
-  private final long updateInterval = Engine.MILLIS_PER_DAY
-      + (long) (Engine.MILLIS_PER_HOUR * 8. * Math.random());
+  private final long updateInterval = DateUtils.DAY_IN_MILLIS
+      + (long) (DateUtils.HOUR_IN_MILLIS * 8. * Math.random());
 
   /**
    * List of meta keys that are allowed to import from a downloaded
    * subscription.
    */
   private static final String[] ALLOWED_META_KEYS_ARRAY =
   {
       "checksum", KEY_VERSION, KEY_TITLE, "last modified", "expires", "homepage", "licence"
   };
 
   private final URL url;
   private final Type type;
   private final HashMap<String, String> meta = new HashMap<>();
   private final HashSet<String> filters = new HashSet<>();
 
   private boolean metaDataValid = true;
   private boolean filtersValid = true;
 
   static
   {
-    for (final String s : ALLOWED_META_KEYS_ARRAY)
-    {
-      ALLOWED_META_KEYS.add(s);
-    }
+    Collections.addAll(ALLOWED_META_KEYS, ALLOWED_META_KEYS_ARRAY);
   }
 
   /**
    * Subscription type.
    *
    * @author René Jeschke &lt;rene@adblockplus.org&gt;
    */
   public enum Type
   {
     /**
@@ skipping 242 matching lines @@
         return "url:" + subscription.url.toString();
       case USER:
         return "user:" + subscription.getMeta(KEY_TITLE);
     }
     return "";
   }
 
   private static String byteArrayToHexString(final byte[] array)
   {
     final StringBuilder sb = new StringBuilder(array.length * 2);
-    for (int i = 0; i < array.length; i++)
+    for (final byte b : array)
     {
-      final int value = array[i] & 255;
+      final int value = b & 255;
       if (value < 16)
       {
         sb.append('0');
       }
       sb.append(Integer.toHexString(value));
     }
     return sb.toString();
   }
 
   private static String createMetaDataHash(final HashMap<String, String> meta) throws IOException
@@ skipping 23 matching lines @@
     }
     catch (final NoSuchAlgorithmException e)
     {
       throw new IOException("MD5 is unavailable: " + e.getMessage(), e);
     }
   }
 
   public void serializeMetaData(final File metaFile) throws IOException
   {
     this.putMeta(KEY_META_HASH, createMetaDataHash(this.meta));
-    try (final DataOutputStream metaOut = new DataOutputStream(new GZIPOutputStream(
-        new BufferedOutputStream(new FileOutputStream(metaFile)))))
+    try (final DataOutputStream metaOut = new DataOutputStream(new BufferedOutputStream(

[anton, 2017/06/02 07:39:56]

here and below: what's the purpose of buffering before gzipping?
As for me it seems reasonable to buffer before writing to file to eliminate file
io routines (as it was before).
What am i missing?

[diegocarloslima, 2017/06/02 21:03:42]

Basically, it's because GZIP Streams already hold a buffer inside them, but they
don't expose this buffer. More info here:
https://stackoverflow.com/questions/4438085/seeking-out-the-optimum-size-for-...

+        new GZIPOutputStream(new FileOutputStream(metaFile)))))
     {
       metaOut.writeUTF(this.url != null ? this.url.toString() : "");
       metaOut.writeInt(this.meta.size());
       for (final Entry<String, String> e : this.meta.entrySet())
       {
         metaOut.writeUTF(e.getKey());
         metaOut.writeUTF(e.getValue());
       }
     }
   }
 
   public void serializeFilters(final File filtersFile) throws IOException
   {
-    try (final DataOutputStream filtersOut = new DataOutputStream(new GZIPOutputStream(
-        new BufferedOutputStream(new FileOutputStream(filtersFile)))))
+    try (final DataOutputStream filtersOut = new DataOutputStream(new BufferedOutputStream(
+        new GZIPOutputStream(new FileOutputStream(filtersFile)))))
     {
       filtersOut.writeInt(this.filters.size());
       filtersOut.writeUTF(createFilterHash(new ArrayList<>(this.filters)));
       for (final String s : this.filters)
       {
         final byte[] b = s.getBytes(StandardCharsets.UTF_8);
         filtersOut.writeInt(b.length);
         filtersOut.write(b);
       }
     }
   }
 
   public void serializeSubscription(final File metaFile, final File filtersFile) throws IOException
   {
     this.serializeMetaData(metaFile);
     this.serializeFilters(filtersFile);
   }
 
   public static Subscription deserializeSubscription(final File metaFile)
   {
     Subscription sub = null;
-    try (final DataInputStream in = new DataInputStream(new GZIPInputStream(new BufferedInputStream(
+    try (final DataInputStream in = new DataInputStream(new BufferedInputStream(new GZIPInputStream(
         new FileInputStream(metaFile)))))
     {
       final String urlString = in.readUTF();
       sub = new Subscription(!TextUtils.isEmpty(urlString) ? new URL(urlString) : null);
       sub.metaDataValid = false;
       final int numMetaEntries = in.readInt();
       for (int i = 0; i < numMetaEntries; i++)
       {
         final String key = in.readUTF();
         final String value = in.readUTF();
         sub.meta.put(key, value);
       }
       sub.metaDataValid = createMetaDataHash(sub.meta).equals(sub.getMeta(KEY_META_HASH));
     }
     catch (Throwable t)
     {
       // We catch Throwable here in order to return whatever we could retrieve from the meta file
     }
     return sub;
   }
 
   public void deserializeFilters(final File filtersFile)
   {
     this.clearFilters();
     this.filtersValid = false;
-    try (final DataInputStream in = new DataInputStream(new GZIPInputStream(new BufferedInputStream(
+    try (final DataInputStream in = new DataInputStream(new BufferedInputStream(new GZIPInputStream(
         new FileInputStream(filtersFile)))))
     {
       final int numFilters = in.readInt();
       final String filtersHash = in.readUTF();
       for (int i = 0; i < numFilters; i++)
       {
         final int length = in.readInt();
         final byte[] b = new byte[length];
         in.readFully(b);
         this.filters.add(new String(b, StandardCharsets.UTF_8));
@@ skipping 125 matching lines @@
     this.serializeMetaData(metaFile);
     if (filtersChanged)
     {
       this.serializeFilters(filtersFile);
       this.clearFilters();
     }
 
     return filtersChanged;
   }
 }