Issue mozilla-mobile#494: Add browser-icon module and icons code

buildSrc/src/main/java/Dependencies.kt

@@ -49,6 +49,7 @@ object Deps {
     const val support_fragment = "com.android.support:support-fragment:${Versions.support_libraries}"
     const val support_constraintlayout = "com.android.support.constraint:constraint-layout:${Versions.constraint_layout}"
     const val support_compat = "com.android.support:support-compat:${Versions.support_libraries}"
+    const val support_palette = "com.android.support:palette-v7:${Versions.support_libraries}"
 
     const val arch_workmanager = "android.arch.work:work-runtime:${Versions.workmanager}"
 

components/browser/icons/README.md

@@ -0,0 +1,23 @@
+# [Android Components](../../../README.md) > Browser > Icons
+
+Favicons support for Android browser apps.
+
+## Usage
+
+### Setting up the dependency
+
+Use gradle to download the library from JCenter:
+
+```Groovy
+implementation "org.mozilla.components:browser-icons:{latest-version}"
+```
+### Quick Start
+
+(TBD)
+
+## License
+
+    This Source Code Form is subject to the terms of the Mozilla Public
+    License, v. 2.0. If a copy of the MPL was not distributed with this
+    file, You can obtain one at http://mozilla.org/MPL/2.0/
+

components/browser/icons/build.gradle

@@ -0,0 +1,61 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ *  License, v. 2.0. If a copy of the MPL was not distributed with this
+ *  file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+apply plugin: 'com.android.library'
+apply plugin: 'kotlin-android'
+
+android {
+    compileSdkVersion Config.compileSdkVersion
+
+    defaultConfig {
+        minSdkVersion Config.minSdkVersion
+        targetSdkVersion Config.targetSdkVersion
+
+        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
+    }
+
+    lintOptions {
+        // Lint reports (falsely) a bunch of unused resources for this project. Those resources
+        // are references from Kotlin code and it looks like Android lint can't see those references
+        // yet. Let's disable this check and retry once a newer SDK is available.
+        disable 'UnusedResources'
+    }
+
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+        }
+    }
+
+}
+
+dependencies {
+    implementation project(':support-ktx')
+    implementation project(':support-base')
+    implementation project(':support-utils')
+
+    implementation Deps.support_annotations
+    implementation Deps.kotlin_stdlib
+
+    testImplementation project(':support-test')
+
+    testImplementation Deps.testing_junit
+    testImplementation Deps.testing_robolectric
+    testImplementation Deps.testing_mockito
+}
+
+archivesBaseName = "icons"
+
+apply from: '../../../publish.gradle'
+ext.configurePublish(
+        'org.mozilla.components',
+        'icons',
+        'Favicons support for Android browser apps.')

components/browser/icons/proguard-rules.pro

@@ -0,0 +1,21 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile

components/browser/icons/src/main/AndroidManifest.xml

@@ -0,0 +1,5 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="mozilla.components.browser.icons" />

components/browser/icons/src/main/java/mozilla/components/browser/icons/IconCallback.java

@@ -0,0 +1,25 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ *  License, v. 2.0. If a copy of the MPL was not distributed with this
+ *  file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ *  License, v. 2.0. If a copy of the MPL was not distributed with this
+ *  file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+/* -*- Mode: Java; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package mozilla.components.browser.icons;
+
+/**
+ * Interface for a callback that will be executed once an icon has been loaded successfully.
+ */
+public interface IconCallback {
+    void onIconResponse(IconResponse response);
+}

components/browser/icons/src/main/java/mozilla/components/browser/icons/IconDescriptor.java

@@ -0,0 +1,125 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ *  License, v. 2.0. If a copy of the MPL was not distributed with this
+ *  file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ *  License, v. 2.0. If a copy of the MPL was not distributed with this
+ *  file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+/* -*- Mode: Java; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package mozilla.components.browser.icons;
+
+import android.support.annotation.IntDef;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.support.annotation.VisibleForTesting;
+
+/**
+ * A class describing the location and properties of an icon that can be loaded.
+ */
+public class IconDescriptor {
+    @IntDef({ TYPE_GENERIC, TYPE_FAVICON, TYPE_TOUCHICON, TYPE_LOOKUP, TYPE_BUNDLED_TILE })
+    @interface IconType {}
+
+    // The type values are used for ranking icons (higher values = try to load first).
+    @VisibleForTesting
+    static final int TYPE_GENERIC = 0;
+    @VisibleForTesting
+    static final int TYPE_LOOKUP = 1;
+    @VisibleForTesting
+    static final int TYPE_FAVICON = 5;
+    @VisibleForTesting
+    static final int TYPE_TOUCHICON = 10;
+    @VisibleForTesting
+    static final int TYPE_BUNDLED_TILE = 15;
+
+    private final String url;
+    private final int size;
+    private final String mimeType;
+    private final int type;
+
+    /**
+     * Create a generic icon located at the given URL. No MIME type or size is known.
+     */
+    public static IconDescriptor createGenericIcon(@NonNull String url) {
+        return new IconDescriptor(TYPE_GENERIC, url, 0, null);
+    }
+
+    /**
+     * Create a favicon located at the given URL and with a known size and MIME type.
+     */
+    public static IconDescriptor createFavicon(@NonNull String url, int size, String mimeType) {
+        return new IconDescriptor(TYPE_FAVICON, url, size, mimeType);
+    }
+
+    /**
+     * Create a touch icon located at the given URL and with a known MIME type and size.
+     */
+    public static IconDescriptor createTouchicon(@NonNull String url, int size, String mimeType) {
+        return new IconDescriptor(TYPE_TOUCHICON, url, size, mimeType);
+    }
+
+    /**
+     * Create an icon located at an URL that has been returned from a disk or memory storage. This
+     * is an icon with an URL we loaded an icon from previously. Therefore we give it a little higher
+     * ranking than a generic icon - even though we do not know the MIME type or size of the icon.
+     */
+    public static IconDescriptor createLookupIcon(@NonNull String url) {
+        return new IconDescriptor(TYPE_LOOKUP, url, 0, null);
+    }
+
+    /**
+     * Create a bundled tile icon at the given URL. MIME type or size is not known until we load
+     * the icons, but we know these icons are high fidelity. (Although the icons are png's at time
+     * of writing, they could be changed to webp or VectorDrawable in future.)
+     */
+    public static IconDescriptor createBundledTileIcon(@NonNull String url) {
+        return new IconDescriptor(TYPE_BUNDLED_TILE, url, 0, null);
+    }
+
+
+    private IconDescriptor(@IconType int type, @NonNull String url, int size, String mimeType) {
+        this.type = type;
+        this.url = url;
+        this.size = size;
+        this.mimeType = mimeType;
+    }
+
+    /**
+     * Get the URL of the icon.
+     */
+    public String getUrl() {
+        return url;
+    }
+
+    /**
+     * Get the (assumed) size of the icon. Returns 0 if no size is known.
+     */
+    public int getSize() {
+        return size;
+    }
+
+    /**
+     * Get the type of the icon (favicon, touch icon, generic, lookup).
+     */
+    @IconType
+    public int getType() {
+        return type;
+    }
+
+    /**
+     * Get the (assumed) MIME type of the icon. Returns null if no MIME type is known.
+     */
+    @Nullable
+    public String getMimeType() {
+        return mimeType;
+    }
+}

components/browser/icons/src/main/java/mozilla/components/browser/icons/IconDescriptorComparator.java

@@ -0,0 +1,79 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ *  License, v. 2.0. If a copy of the MPL was not distributed with this
+ *  file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ *  License, v. 2.0. If a copy of the MPL was not distributed with this
+ *  file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+/* -*- Mode: Java; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package mozilla.components.browser.icons;
+
+import java.util.Comparator;
+
+/**
+ * This comparator implementation compares IconDescriptor objects in order to determine which icon
+ * to load first.
+ *
+ * In general this comparator will try touch icons before favicons (they usually have a higher resolution)
+ * and prefers larger icons over smaller ones.
+ */
+/* package-private */ class IconDescriptorComparator implements Comparator<IconDescriptor> {
+    @Override
+    public int compare(final IconDescriptor lhs, final IconDescriptor rhs) {
+        if (lhs.getUrl().equals(rhs.getUrl())) {
+            // Two descriptors pointing to the same URL are always referencing the same icon. So treat
+            // them as equal.
+            return 0;
+        }
+
+        // First compare the types. We prefer touch icons because they tend to have a higher resolution
+        // than ordinary favicons.
+        if (lhs.getType() != rhs.getType()) {
+            return compareType(lhs, rhs);
+        }
+
+        // If one of them is larger than pick the larger icon.
+        if (lhs.getSize() != rhs.getSize()) {
+            return compareSizes(lhs, rhs);
+        }
+
+        // If there's no other way to choose, we prefer container types. They *might* contain
+        // an image larger than the size given in the <link> tag.
+        final boolean lhsContainer = IconsHelper.isContainerType(lhs.getMimeType());
+        final boolean rhsContainer = IconsHelper.isContainerType(rhs.getMimeType());
+
+        if (lhsContainer != rhsContainer) {
+            return lhsContainer ? -1 : 1;
+        }
+
+        // There's no way to know which icon might be better. However we need to pick a consistent
+        // one to avoid breaking the TreeSet implementation (See Bug 1331808). Therefore we are
+        // picking one by just comparing the URLs.
+        return lhs.getUrl().compareTo(rhs.getUrl());
+    }
+
+    private int compareType(IconDescriptor lhs, IconDescriptor rhs) {
+        if (lhs.getType() > rhs.getType()) {
+            return -1;
+        } else {
+            return 1;
+        }
+    }
+
+    private int compareSizes(IconDescriptor lhs, IconDescriptor rhs) {
+        if (lhs.getSize() > rhs.getSize()) {
+            return -1;
+        } else {
+            return 1;
+        }
+    }
+}