Issue 5931 - Create tests for util package

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

Index: adblockplussbrowser/src/main/java/org/adblockplus/sbrowser/contentblocker/engine/Subscription.java
===================================================================
new file mode 100644
--- /dev/null
+++ b/adblockplussbrowser/src/main/java/org/adblockplus/sbrowser/contentblocker/engine/Subscription.java
@@ -0,0 +1,609 @@
+/*
+ * This file is part of Adblock Plus <https://adblockplus.org/>,
+ * Copyright (C) 2006-present 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
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.adblockplus.sbrowser.contentblocker.engine;
+
+import java.io.BufferedInputStream;
+import java.io.BufferedOutputStream;
+import java.io.BufferedReader;
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.StringReader;
+import java.net.URL;
+import java.nio.charset.StandardCharsets;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+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_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_META_HASH = "_meta_hash";
+
+  private static final long MINIMAL_DOWNLOAD_INTERVAL = DateUtils.HOUR_IN_MILLIS / 4;
+  private static final long DOWNLOAD_RETRY_INTERVAL = DateUtils.HOUR_IN_MILLIS;
+
+  /**
+   * 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 static final HashSet<String> ALLOWED_META_KEYS =
+      new HashSet<>(Arrays.asList(ALLOWED_META_KEYS_ARRAY));
+
+  private static final Locale LOCALE_EN = Locale.ENGLISH;
+
+  private final long updateInterval = DateUtils.DAY_IN_MILLIS
+      + (long) (DateUtils.HOUR_IN_MILLIS * 8. * Math.random());
+
+  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;
+
+  /**
+   * Subscription type.
+   *
+   * @author René Jeschke &lt;rene@adblockplus.org&gt;
+   */
+  public enum Type
+  {
+    /**
+     * Initiated from an URL, can be automatically downloaded.
+     */
+    DOWNLOADABLE,
+    /**
+     * User defined filters or exceptions.
+     */
+    USER
+  }
+
+  /**
+   * Creates a subscription. The type gets determined by {@code url} being
+   * {@code null} or not.
+   *
+   * @param url
+   * @see Subscription.Type
+   */
+  private Subscription(final URL url)
+  {
+    this.url = url;
+    this.type = url != null ? Type.DOWNLOADABLE : Type.USER;
+  }
+
+  /**
+   * Creates a {@code USER} subscription.
+   *
+   * @see Subscription.Type
+   */
+  private Subscription()
+  {
+    this.url = null;
+    this.type = Type.USER;
+  }
+
+  public boolean isMetaDataValid()
+  {
+    return this.metaDataValid;
+  }
+
+  public boolean isFiltersValid()
+  {
+    return this.filtersValid;
+  }
+
+  static long parseLong(final String number)
+  {
+    try
+    {
+      return Long.parseLong(number);
+    }
+    catch (final NumberFormatException nfe)
+    {
+      return 0;
+    }
+  }
+
+  public long getVersion()
+  {
+    return parseLong(this.getMeta(KEY_VERSION, "0"));
+  }
+
+  public long getDownloadCount()
+  {
+    return parseLong(this.getMeta(KEY_DOWNLOAD_COUNT, "0"));
+  }
+
+  public long getLastUpdateTimestamp()
+  {
+    return parseLong(this.getMeta(KEY_UPDATE_TIMESTAMP, "0"));
+  }
+
+  public long getLastTriedUpdateTimestamp()
+  {
+    return parseLong(this.getMeta(KEY_TRIED_UPDATE_TIMESTAMP, "0"));
+  }
+
+  public boolean shouldUpdate(final boolean forced)
+  {
+    final long now = System.currentTimeMillis();
+    final long lastUpdate = this.getLastUpdateTimestamp();
+    final long lastTry = this.getLastTriedUpdateTimestamp();
+
+    if (forced)
+    {
+      return now - Math.max(lastUpdate, lastTry) > MINIMAL_DOWNLOAD_INTERVAL;
+    }
+
+    if (lastTry > lastUpdate)
+    {
+      return now - lastTry > DOWNLOAD_RETRY_INTERVAL;
+    }
+    else
+    {
+      return now - lastUpdate > this.updateInterval;
+    }
+  }
+
+  /**
+   * @return the download URL, null for a {@code USER} subscription.
+   */
+  public URL getURL()
+  {
+    return this.url;
+  }
+
+  /**
+   * @return the type of this subscription
+   * @see Subscription.Type
+   */
+  public Type getType()
+  {
+    return this.type;
+  }
+
+  /**
+   * Retrieves a meta data entry
+   *
+   * @param key
+   *          gets converted to all lower case
+   * @param defaultValue
+   * @return the meta data or {@code defaultValue} if not defined
+   */
+  public String getMeta(final String key, final String defaultValue)
+  {
+    final String value = this.meta.get(key.toLowerCase(LOCALE_EN));
+    return value != null ? value : defaultValue;
+  }
+
+  /**
+   * Retrieves a meta data entry
+   *
+   * @param key
+   *          gets converted to all lower case
+   * @return the meta data or {@code null} if not defined
+   */
+  public String getMeta(final String key)
+  {
+    return this.meta.get(key.toLowerCase(LOCALE_EN));
+  }
+
+  public String putMeta(final String key, final String value)
+  {
+    return this.meta.put(key, value);
+  }
+
+  public String getTitle()
+  {
+    final String title = this.getMeta(KEY_TITLE);
+    return title != null ? title : this.url.toString();
+  }
+
+  /**
+   * Creates a {@code DOWNLOADABLE} subscription.
+   *
+   * @param url
+   *          the update URL
+   * @param lines
+   * @return the subscription
+   * @see Subscription.Type
+   */
+  public static Subscription create(final URL url, final List<String> lines)
+  {
+    final Subscription sub = new Subscription(url);
+    sub.parseLines(lines);
+    return sub;
+  }
+
+  /**
+   * Creates a {@code DOWNLOADABLE} subscription.
+   *
+   * @param url
+   *          the update URL
+   * @return the subscription
+   * @see Subscription.Type
+   */
+  public static Subscription create(final URL url)
+  {
+    return new Subscription(url);
+  }
+
+  public static Subscription create(final String urlString) throws IOException
+  {
+    try
+    {
+      return new Subscription(new URL(urlString));
+    }
+    catch (final IOException e)
+    {
+      Log.d(TAG, "Creation failed for: '" + urlString + "'");
+      throw e;
+    }
+  }
+
+  /**
+   * Creates a {@code USER} subscription.
+   *
+   * @param title
+   * @return the subscription
+   * @see Subscription.Type
+   */
+  public static Subscription createUserSubscription(final String title)
+  {
+    final Subscription sub = new Subscription();
+    sub.meta.put(KEY_TITLE, title);
+    return sub;
+  }
+
+  public boolean isEnabled()
+  {
+    return "true".equals(this.getMeta(KEY_ENABLED));
+  }
+
+  public void setEnabled(boolean enable)
+  {
+    this.putMeta(KEY_ENABLED, Boolean.toString(enable));
+  }
+
+  public void copyFilters(Collection<String> filters)
+  {
+    if (filters != null)
+    {
+      filters.addAll(this.filters);
+    }
+  }
+
+  public void clearFilters()
+  {
+    this.filters.clear();
+  }
+
+  /**
+   * @return an internal management ID
+   */
+  public String getId()
+  {
+    return getId(this);
+  }
+
+  public static String getId(final Subscription subscription)
+  {
+    switch (subscription.type)
+    {
+      case DOWNLOADABLE:
+        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 (final byte b : array)
+    {
+      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
+  {
+    final ArrayList<String> keyValues = new ArrayList<>();
+    for (final Entry<String, String> e : meta.entrySet())
+    {
+      if (!KEY_META_HASH.equals(e.getKey()))
+      {
+        keyValues.add(e.getKey() + ":" + e.getValue());
+      }
+    }
+    return createFilterHash(keyValues);
+  }
+
+  private static String createFilterHash(List<String> filters) throws IOException
+  {
+    try
+    {
+      final MessageDigest md5 = MessageDigest.getInstance("MD5");
+      Collections.sort(filters);
+      for (final String filter : filters)
+      {
+        md5.update(filter.getBytes(StandardCharsets.UTF_8));
+      }
+      return byteArrayToHexString(md5.digest());
+    }
+    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 BufferedOutputStream(
+        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 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 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 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));
+      }
+      this.filtersValid = createFilterHash(new ArrayList<>(this.filters)).equals(
+          filtersHash);
+      Log.d(TAG, "Filters valid: " + this.filtersValid);
+    }
+    catch (Throwable t)
+    {
+      // We catch Throwable here in order to load whatever we could retrieve from the filters file
+    }
+  }
+
+  /**
+   * Adds the given string, which should be a single filter to this
+   * subscription.
+   *
+   * @param input
+   */
+  public Subscription parseLine(String input)
+  {
+    final String line = input.trim();
+    if (!line.isEmpty())
+    {
+      if (line.startsWith("!"))
+      {
+        // Meta data
+        final int colon = line.indexOf(':');
+        if (colon > 2)
+        {
+          final String key = line.substring(1, colon).trim().toLowerCase(LOCALE_EN);
+          final String value = line.substring(colon + 1).trim();
+          if (!key.isEmpty() && !value.isEmpty() && ALLOWED_META_KEYS.contains(key))
+          {
+            this.meta.put(key, value);
+          }
+        }
+      }
+      else if (line.startsWith("["))
+      {
+        // currently ignored
+      }
+      else
+      {
+        this.filters.add(line);
+      }
+    }
+    return this;
+  }
+
+  public Subscription parseLines(final List<String> lines)
+  {
+    for (String line : lines)
+    {
+      this.parseLine(line);
+    }
+    return this;
+  }
+
+  public Subscription parseText(final String string)
+  {
+    try (final BufferedReader r = new BufferedReader(new StringReader(string)))
+    {
+      for (String line = r.readLine(); line != null; line = r.readLine())
+      {
+        this.parseLine(line);
+      }
+    }
+    catch (final IOException e)
+    {
+      // ignored ... we're reading from a String
+    }
+    return this;
+  }
+
+  boolean updateSubscription(final int responseCode, final String text,
+      final Map<String, String> httpHeaders, final File metaFile, final File filtersFile)
+      throws IOException
+  {
+    boolean filtersChanged = false;
+    if (responseCode == 304)
+    {
+      // Not changed, update update timestamp only
+      this.meta.put(KEY_UPDATE_TIMESTAMP, Long.toString(System.currentTimeMillis()));
+    }
+    else
+    {
+      if (responseCode != 200 || text == null)
+      {
+        // We tried, but we failed
+        this.meta.put(KEY_TRIED_UPDATE_TIMESTAMP, Long.toString(System.currentTimeMillis()));
+      }
+      else
+      {
+        // Update succeeded, update filters
+        filtersChanged = true;
+        this.meta.put(KEY_UPDATE_TIMESTAMP, Long.toString(System.currentTimeMillis()));
+        if (httpHeaders != null)
+        {
+          final String etag = httpHeaders.get("etag");
+          final String lastModified = httpHeaders.get("last-modified");
+
+          if (etag != null)
+          {
+            this.meta.put(KEY_HTTP_ETAG, etag);
+          }
+          else
+          {
+            this.meta.remove(KEY_HTTP_ETAG);
+          }
+
+          if (lastModified != null)
+          {
+            this.meta.put(KEY_HTTP_LAST_MODIFIED, lastModified);
+          }
+          else
+          {
+            this.meta.remove(KEY_HTTP_LAST_MODIFIED);
+          }
+          this.meta.put(KEY_DOWNLOAD_COUNT, Long.toString(this.getDownloadCount() + 1));
+
+          this.clearFilters();
+          this.parseText(text);
+        }
+      }
+    }
+
+    this.serializeMetaData(metaFile);
+    if (filtersChanged)
+    {
+      this.serializeFilters(filtersFile);
+      this.clearFilters();
+    }
+
+    return filtersChanged;
+  }
+}