content: /*
   * Copyright (C) 2018 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.layoutlib.bridge.resources;
  
  import com.android.layoutlib.bridge.bars.Config;
  import com.android.resources.Density;
  import com.android.resources.LayoutDirection;
  
  import java.io.InputStream;
  
  public class IconLoader {
  
      private final String mIconName;
      private final Density mDesiredDensity;
      private final int mPlatformVersion;
      private final LayoutDirection mDirection;
  
      private Density mCurrentDensity;
      private StringBuilder mCurrentPath;
  
      public IconLoader(String iconName, Density density, int platformVersion, LayoutDirection
              direction) {
          mIconName = iconName;
          mDesiredDensity = density;
          mPlatformVersion = platformVersion;
          mDirection = direction;
          // An upper bound on the length of the path for the icon: /bars/v21/ldrtl-xxxhdpi/
          final int iconPathLength = 24;
          mCurrentPath = new StringBuilder(iconPathLength + iconName.length());
      }
  
      public InputStream getIcon() {
          for (String resourceDir : Config.getResourceDirs(mPlatformVersion)) {
              mCurrentDensity = null;
              InputStream stream = getIcon(resourceDir);
              if (stream != null) {
                  return stream;
              }
          }
          return null;
      }
  
      /**
       * Should only be called after {@link #getIcon()}. Returns the density of the icon, if found by
       * {@code getIcon()}. If no icon was found, then the return value has no meaning.
       */
      public Density getDensity() {
          return mCurrentDensity;
      }
  
      /**
       * Should only be called after {@link #getIcon()}. Returns the path to the icon, if found by
       * {@code getIcon()}. If no icon was found, then the return value has no meaning.
       */
      public String getPath() {
          return mCurrentPath.toString();
      }
  
      /**
       * Search for icon in the resource directory. This iterates over all densities.
       * If a match is found, mCurrentDensity will be set to the icon's density.
       */
      private InputStream getIcon(String resourceDir) {
          // First check for the desired density.
          InputStream stream = getIcon(resourceDir, mDesiredDensity);
          if (stream != null) {
              mCurrentDensity = mDesiredDensity;
              return stream;
          }
          // Didn't find in the desired density. Search in all.
          for (Density density : Density.values()) {
              if (density == mDesiredDensity) {
                  // Skip the desired density since it's already been checked.
                  continue;
              }
              stream = getIcon(resourceDir, density);
              if (stream != null) {
                  mCurrentDensity = density;
                  return stream;
              }
          }
          return null;
      }
  
      /**
       * Returns the icon for given density present in the given resource directory, taking layout
       * direction into consideration.
       */
      private InputStream getIcon(String resourceDir, Density density) {
          mCurrentPath.setLength(0);
          // Currently we don't have any LTR only resources and hence the check is skipped. If they
          // are ever added, change to:
          // if (mDirection == LayoutDirection.RTL || mDirection == LayoutDirection.LTR) {
          if (mDirection == LayoutDirection.RTL) {
              mCurrentPath.append(resourceDir)
                      .append(mDirection.getResourceValue())
                      .append('-')
                      .append(density.getResourceValue())
                      .append('/')
                      .append(mIconName);
              InputStream stream = getClass().getResourceAsStream(mCurrentPath.toString());
              if (stream != null) {
                  return stream;
              }
              mCurrentPath.setLength(0);
          }
          mCurrentPath.append(resourceDir)
                  .append(density.getResourceValue())
                  .append('/')
                  .append(mIconName);
          return getClass().getResourceAsStream(mCurrentPath.toString());
      }
  }
  