1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/mobile/android/base/favicons/cache/FaviconCacheElement.java Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,115 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +package org.mozilla.gecko.favicons.cache;
1.9 +
1.10 +import android.graphics.Bitmap;
1.11 +
1.12 +/**
1.13 + * Objects stored in the Favicon cache - allow for the bitmap to be tagged to indicate if it has
1.14 + * been scaled. Unscaled bitmaps are not included in the scaled-bitmap cache's size calculation.
1.15 + */
1.16 +public class FaviconCacheElement implements Comparable<FaviconCacheElement> {
1.17 + // Was this Favicon computed via scaling another primary Favicon, or is this a primary Favicon?
1.18 + final boolean isPrimary;
1.19 +
1.20 + // The Favicon bitmap.
1.21 + Bitmap faviconPayload;
1.22 +
1.23 + // If set, faviconPayload is absent. Since the underlying ICO may contain multiple primary
1.24 + // payloads, primary payloads are never truly deleted from the cache, but instead have their
1.25 + // payload deleted and this flag set on their FaviconCacheElement. That way, the cache always
1.26 + // has a record of the existence of a primary payload, even if it is no longer in the cache.
1.27 + // This means that when a request comes in that will be best served using a primary that is in
1.28 + // the database but no longer cached, we know that it exists and can go get it (Useful when ICO
1.29 + // support is added).
1.30 + volatile boolean invalidated;
1.31 +
1.32 + final int imageSize;
1.33 +
1.34 + // Used for LRU pruning.
1.35 + final FaviconsForURL backpointer;
1.36 +
1.37 + public FaviconCacheElement(Bitmap payload, boolean primary, int size, FaviconsForURL backpointer) {
1.38 + this.faviconPayload = payload;
1.39 + this.isPrimary = primary;
1.40 + this.imageSize = size;
1.41 + this.backpointer = backpointer;
1.42 + }
1.43 +
1.44 + public FaviconCacheElement(Bitmap faviconPayload, boolean isPrimary, FaviconsForURL backpointer) {
1.45 + this.faviconPayload = faviconPayload;
1.46 + this.isPrimary = isPrimary;
1.47 + this.backpointer = backpointer;
1.48 +
1.49 + if (faviconPayload != null) {
1.50 + imageSize = faviconPayload.getWidth();
1.51 + } else {
1.52 + imageSize = 0;
1.53 + }
1.54 + }
1.55 +
1.56 + public int sizeOf() {
1.57 + if (invalidated) {
1.58 + return 0;
1.59 + }
1.60 + return faviconPayload.getRowBytes() * faviconPayload.getHeight();
1.61 + }
1.62 +
1.63 + /**
1.64 + * Establish an ordering on FaviconCacheElements based on size and validity. An element is
1.65 + * considered "greater than" another if it is valid and the other is not, or if it contains a
1.66 + * larger payload.
1.67 + *
1.68 + * @param another The FaviconCacheElement to compare to this one.
1.69 + * @return -1 if this element is less than the given one, 1 if the other one is larger than this
1.70 + * and 0 if both are of equal value.
1.71 + */
1.72 + @Override
1.73 + public int compareTo(FaviconCacheElement another) {
1.74 + if (invalidated && !another.invalidated) {
1.75 + return -1;
1.76 + }
1.77 +
1.78 + if (!invalidated && another.invalidated) {
1.79 + return 1;
1.80 + }
1.81 +
1.82 + if (invalidated) {
1.83 + return 0;
1.84 + }
1.85 +
1.86 + final int w1 = imageSize;
1.87 + final int w2 = another.imageSize;
1.88 + if (w1 > w2) {
1.89 + return 1;
1.90 + } else if (w2 > w1) {
1.91 + return -1;
1.92 + }
1.93 + return 0;
1.94 + }
1.95 +
1.96 + /**
1.97 + * Called when this element is evicted from the cache.
1.98 + *
1.99 + * If primary, drop the payload and set invalid. If secondary, just unlink from parent node.
1.100 + */
1.101 + public void onEvictedFromCache() {
1.102 + if (isPrimary) {
1.103 + // So we keep a record of which primaries exist in the database for this URL, we
1.104 + // don't actually delete the entry for primaries. Instead, we delete their payload
1.105 + // and flag them as invalid. This way, we can later figure out that what a request
1.106 + // really want is one of the primaries that have been dropped from the cache, and we
1.107 + // can go get it.
1.108 + invalidated = true;
1.109 + faviconPayload = null;
1.110 + } else {
1.111 + // Secondaries don't matter - just delete them.
1.112 + if (backpointer == null) {
1.113 + return;
1.114 + }
1.115 + backpointer.favicons.remove(this);
1.116 + }
1.117 + }
1.118 +}
