store/imap/ImapList.java

/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.voicemail.impl.mail.store.imap;

import java.util.ArrayList;

/** Class represents an IMAP list. */
public class ImapList extends ImapElement {
  /** {@link ImapList} representing an empty list. */
  public static final ImapList EMPTY =
      new ImapList() {
        @Override
        public void destroy() {
          // Don't call super.destroy().
          // It's a shared object.  We don't want the mDestroyed to be set on this.
        }

        @Override
        void add(ImapElement e) {
          throw new RuntimeException();
        }
      };

  private ArrayList<ImapElement> mList = new ArrayList<ImapElement>();

  /* package */ void add(ImapElement e) {
    if (e == null) {
      throw new RuntimeException("Can't add null");
    }
    mList.add(e);
  }

  @Override
  public final boolean isString() {
    return false;
  }

  @Override
  public final boolean isList() {
    return true;
  }

  public final int size() {
    return mList.size();
  }

  public final boolean isEmpty() {
    return size() == 0;
  }

  /**
   * Return true if the element at {@code index} exists, is string, and equals to {@code s}. (case
   * insensitive)
   */
  public final boolean is(int index, String s) {
    return is(index, s, false);
  }

  /** Same as {@link #is(int, String)}, but does the prefix match if {@code prefixMatch}. */
  public final boolean is(int index, String s, boolean prefixMatch) {
    if (!prefixMatch) {
      return getStringOrEmpty(index).is(s);
    } else {
      return getStringOrEmpty(index).startsWith(s);
    }
  }

  /**
   * Return the element at {@code index}. If {@code index} is out of range, returns {@link
   * ImapElement#NONE}.
   */
  public final ImapElement getElementOrNone(int index) {
    return (index >= mList.size()) ? ImapElement.NONE : mList.get(index);
  }

  /**
   * Return the element at {@code index} if it's a list. If {@code index} is out of range or not a
   * list, returns {@link ImapList#EMPTY}.
   */
  public final ImapList getListOrEmpty(int index) {
    ImapElement el = getElementOrNone(index);
    return el.isList() ? (ImapList) el : EMPTY;
  }

  /**
   * Return the element at {@code index} if it's a string. If {@code index} is out of range or not a
   * string, returns {@link ImapString#EMPTY}.
   */
  public final ImapString getStringOrEmpty(int index) {
    ImapElement el = getElementOrNone(index);
    return el.isString() ? (ImapString) el : ImapString.EMPTY;
  }

  /**
   * Return an element keyed by {@code key}. Return null if not found. {@code key} has to be at an
   * even index.
   */
  /* package */ final ImapElement getKeyedElementOrNull(String key, boolean prefixMatch) {
    for (int i = 1; i < size(); i += 2) {
      if (is(i - 1, key, prefixMatch)) {
        return mList.get(i);
      }
    }
    return null;
  }

  /**
   * Return an {@link ImapList} keyed by {@code key}. Return {@link ImapList#EMPTY} if not found.
   */
  public final ImapList getKeyedListOrEmpty(String key) {
    return getKeyedListOrEmpty(key, false);
  }

  /**
   * Return an {@link ImapList} keyed by {@code key}. Return {@link ImapList#EMPTY} if not found.
   */
  public final ImapList getKeyedListOrEmpty(String key, boolean prefixMatch) {
    ImapElement e = getKeyedElementOrNull(key, prefixMatch);
    return (e != null) ? ((ImapList) e) : ImapList.EMPTY;
  }

  /**
   * Return an {@link ImapString} keyed by {@code key}. Return {@link ImapString#EMPTY} if not
   * found.
   */
  public final ImapString getKeyedStringOrEmpty(String key) {
    return getKeyedStringOrEmpty(key, false);
  }

  /**
   * Return an {@link ImapString} keyed by {@code key}. Return {@link ImapString#EMPTY} if not
   * found.
   */
  public final ImapString getKeyedStringOrEmpty(String key, boolean prefixMatch) {
    ImapElement e = getKeyedElementOrNull(key, prefixMatch);
    return (e != null) ? ((ImapString) e) : ImapString.EMPTY;
  }

  /** Return true if it contains {@code s}. */
  public final boolean contains(String s) {
    for (int i = 0; i < size(); i++) {
      if (getStringOrEmpty(i).is(s)) {
        return true;
      }
    }
    return false;
  }

  @Override
  public void destroy() {
    if (mList != null) {
      for (ImapElement e : mList) {
        e.destroy();
      }
      mList = null;
    }
    super.destroy();
  }

  @Override
  public String toString() {
    return mList.toString();
  }

  /** Return the text representations of the contents concatenated with ",". */
  public final String flatten() {
    return flatten(new StringBuilder()).toString();
  }

  /**
   * Returns text representations (i.e. getString()) of contents joined together with "," as the
   * separator.
   *
   * <p>Only used for building the capability string passed to vendor policies.
   *
   * <p>We can't use toString(), because it's for debugging (meaning the format may change any
   * time), and it won't expand literals.
   */
  private final StringBuilder flatten(StringBuilder sb) {
    sb.append('[');
    for (int i = 0; i < mList.size(); i++) {
      if (i > 0) {
        sb.append(',');
      }
      final ImapElement e = getElementOrNone(i);
      if (e.isList()) {
        getListOrEmpty(i).flatten(sb);
      } else if (e.isString()) {
        sb.append(getStringOrEmpty(i).getString());
      }
    }
    sb.append(']');
    return sb;
  }

  @Override
  public boolean equalsForTest(ImapElement that) {
    if (!super.equalsForTest(that)) {
      return false;
    }
    ImapList thatList = (ImapList) that;
    if (size() != thatList.size()) {
      return false;
    }
    for (int i = 0; i < size(); i++) {
      if (!mList.get(i).equalsForTest(thatList.getElementOrNone(i))) {
        return false;
      }
    }
    return true;
  }
}