michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: package org.mozilla.gecko.favicons.cache;
michael@0: 
michael@0: import android.graphics.Bitmap;
michael@0: import android.util.Log;
michael@0: import org.mozilla.gecko.gfx.BitmapUtils;
michael@0: 
michael@0: import java.util.ArrayList;
michael@0: import java.util.Collections;
michael@0: 
michael@0: public class FaviconsForURL {
michael@0:     private static final String LOGTAG = "FaviconForURL";
michael@0: 
michael@0:     private volatile int dominantColor = -1;
michael@0: 
michael@0:     final long downloadTimestamp;
michael@0:     final ArrayList<FaviconCacheElement> favicons;
michael@0: 
michael@0:     public final boolean hasFailed;
michael@0: 
michael@0:     public FaviconsForURL(int size) {
michael@0:         this(size, false);
michael@0:     }
michael@0: 
michael@0:     public FaviconsForURL(int size, boolean failed) {
michael@0:         hasFailed = failed;
michael@0:         downloadTimestamp = System.currentTimeMillis();
michael@0:         favicons = new ArrayList<FaviconCacheElement>(size);
michael@0:     }
michael@0: 
michael@0:     public FaviconCacheElement addSecondary(Bitmap favicon, int imageSize) {
michael@0:         return addInternal(favicon, false, imageSize);
michael@0:     }
michael@0: 
michael@0:     public FaviconCacheElement addPrimary(Bitmap favicon) {
michael@0:         return addInternal(favicon, true, favicon.getWidth());
michael@0:     }
michael@0: 
michael@0:     private FaviconCacheElement addInternal(Bitmap favicon, boolean isPrimary, int imageSize) {
michael@0:         FaviconCacheElement c = new FaviconCacheElement(favicon, isPrimary, imageSize, this);
michael@0: 
michael@0:         int index = Collections.binarySearch(favicons, c);
michael@0: 
michael@0:         // We've already got an equivalent one. We don't care about this new one. This only occurs in certain obscure
michael@0:         // case conditions.
michael@0:         if (index >= 0) {
michael@0:             return favicons.get(index);
michael@0:         }
michael@0: 
michael@0:         // binarySearch returns -x - 1 where x is the insertion point of the element. Convert
michael@0:         // this to the actual insertion point..
michael@0:         index++;
michael@0:         index = -index;
michael@0:         favicons.add(index, c);
michael@0: 
michael@0:         return c;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Get the index of the smallest image in this collection larger than or equal to
michael@0:      * the given target size.
michael@0:      *
michael@0:      * @param targetSize Minimum size for the desired result.
michael@0:      * @return The index of the smallest image larger than the target size, or -1 if none exists.
michael@0:      */
michael@0:     public int getNextHighestIndex(int targetSize) {
michael@0:         // Create a dummy object to hold the target value for comparable.
michael@0:         FaviconCacheElement dummy = new FaviconCacheElement(null, false, targetSize, null);
michael@0: 
michael@0:         int index = Collections.binarySearch(favicons, dummy);
michael@0: 
michael@0:         // The search routine returns the index of an element equal to dummy, if present.
michael@0:         // Otherwise, it returns -x - 1, where x is the index in the ArrayList where dummy would be
michael@0:         // inserted if the list were to remain sorted.
michael@0:         if (index < 0) {
michael@0:             index++;
michael@0:             index = -index;
michael@0:         }
michael@0: 
michael@0:         // index is now 'x', as described above.
michael@0: 
michael@0:         // The routine will return favicons.size() as the index iff dummy is larger than all elements
michael@0:         // present (So the "index at which it should be inserted" is the index after the end.
michael@0:         // In this case, we set the sentinel value -1 to indicate that we just requested something
michael@0:         // larger than all primaries.
michael@0:         if (index == favicons.size()) {
michael@0:             index = -1;
michael@0:         }
michael@0: 
michael@0:         return index;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Get the next valid primary icon from this collection, starting at the given index.
michael@0:      * If the appropriate icon is found, but is invalid, we return null - the proper response is to
michael@0:      * reacquire the primary from the database.
michael@0:      * If no icon is found, the search is repeated going backwards from the start index to find any
michael@0:      * primary at all (The input index may be a secondary which is larger than the actual available
michael@0:      * primary.)
michael@0:      *
michael@0:      * @param fromIndex The index into favicons from which to start the search.
michael@0:      * @return The FaviconCacheElement of the next valid primary from the given index. If none exists,
michael@0:      *         then returns the previous valid primary. If none exists, returns null (Insanity.).
michael@0:      */
michael@0:     public FaviconCacheElement getNextPrimary(final int fromIndex) {
michael@0:         final int numIcons = favicons.size();
michael@0: 
michael@0:         int searchIndex = fromIndex;
michael@0:         while (searchIndex < numIcons) {
michael@0:             FaviconCacheElement element = favicons.get(searchIndex);
michael@0: 
michael@0:             if (element.isPrimary) {
michael@0:                 if (element.invalidated) {
michael@0:                     // We return null here, despite the possible existence of other primaries,
michael@0:                     // because we know the most suitable primary for this request exists, but is
michael@0:                     // no longer in the cache. By returning null, we cause the caller to load the
michael@0:                     // missing primary from the database and call again.
michael@0:                     return null;
michael@0:                 }
michael@0:                 return element;
michael@0:             }
michael@0:             searchIndex++;
michael@0:         }
michael@0: 
michael@0:         // No larger primary available. Let's look for smaller ones...
michael@0:         searchIndex = fromIndex - 1;
michael@0:         while (searchIndex >= 0) {
michael@0:             FaviconCacheElement element = favicons.get(searchIndex);
michael@0: 
michael@0:             if (element.isPrimary) {
michael@0:                 if (element.invalidated) {
michael@0:                     return null;
michael@0:                 }
michael@0:                 return element;
michael@0:             }
michael@0:             searchIndex--;
michael@0:         }
michael@0: 
michael@0:         Log.e(LOGTAG, "No primaries found in Favicon cache structure. This is madness!");
michael@0: 
michael@0:         return null;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Ensure the dominant colour field is populated for this favicon.
michael@0:      */
michael@0:     public int ensureDominantColor() {
michael@0:         if (dominantColor == -1) {
michael@0:             // Find a payload, any payload, that is not invalidated.
michael@0:             for (FaviconCacheElement element : favicons) {
michael@0:                 if (!element.invalidated) {
michael@0:                     dominantColor = BitmapUtils.getDominantColor(element.faviconPayload);
michael@0:                     return dominantColor;
michael@0:                 }
michael@0:             }
michael@0:             dominantColor = 0xFFFFFF;
michael@0:         }
michael@0: 
michael@0:         return dominantColor;
michael@0:     }
michael@0: }