pt 1 in reviving the android build (copied from pm 28a1, wish me luck)

mobile/android/base/java/org/mozilla/gecko/activitystream/ActivityStream.java

@@ -0,0 +1,149 @@
+/* -*- 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 org.mozilla.gecko.activitystream;
+
+import android.content.Context;
+import android.net.Uri;
+import android.os.AsyncTask;
+import android.text.TextUtils;
+
+import com.keepsafe.switchboard.SwitchBoard;
+
+import org.mozilla.gecko.AppConstants;
+import org.mozilla.gecko.Experiments;
+import org.mozilla.gecko.GeckoSharedPrefs;
+import org.mozilla.gecko.preferences.GeckoPreferences;
+import org.mozilla.gecko.util.StringUtils;
+import org.mozilla.gecko.util.publicsuffix.PublicSuffix;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class ActivityStream {
+    /**
+     * List of undesired prefixes for labels based on a URL.
+     *
+     * This list is by no means complete and is based on those sources:
+     * - https://gist.github.com/nchapman/36502ad115e8825d522a66549971a3f0
+     * - https://github.com/mozilla/activity-stream/issues/1311
+     */
+    private static final List<String> UNDESIRED_LABEL_PREFIXES = Arrays.asList(
+            "index.",
+            "home."
+    );
+
+    /**
+     * Undesired labels for labels based on a URL.
+     *
+     * This list is by no means complete and is based on those sources:
+     * - https://gist.github.com/nchapman/36502ad115e8825d522a66549971a3f0
+     * - https://github.com/mozilla/activity-stream/issues/1311
+     */
+    private static final List<String> UNDESIRED_LABELS = Arrays.asList(
+            "render",
+            "login",
+            "edit"
+    );
+
+    public static boolean isEnabled(Context context) {
+        if (!isUserEligible(context)) {
+            // If the user is not eligible then disable activity stream. Even if it has been
+            //  enabled before.
+            return false;
+        }
+
+        return GeckoSharedPrefs.forApp(context)
+                .getBoolean(GeckoPreferences.PREFS_ACTIVITY_STREAM, false);
+    }
+
+    /**
+     * Is the user eligible to use activity stream or should we hide it from settings etc.?
+     */
+    public static boolean isUserEligible(Context context) {
+        if (AppConstants.MOZ_ANDROID_ACTIVITY_STREAM) {
+            // If the build flag is enabled then just show the option to the user.
+            return true;
+        }
+
+        if (AppConstants.NIGHTLY_BUILD && SwitchBoard.isInExperiment(context, Experiments.ACTIVITY_STREAM)) {
+            // If this is a nightly build and the user is part of the activity stream experiment then
+            // the option should be visible too. The experiment is limited to Nightly too but I want
+            // to make really sure that this isn't riding the trains accidentally.
+            return true;
+        }
+
+        // For everyone else activity stream is not available yet.
+        return false;
+    }
+
+    /**
+     * Query whether we want to display Activity Stream as a Home Panel (within the HomePager),
+     * or as a HomePager replacement.
+     */
+    public static boolean isHomePanel() {
+        return true;
+    }
+
+    /**
+     * Extract a label from a URL to use in Activity Stream.
+     *
+     * This method implements the proposal from this desktop AS issue:
+     * https://github.com/mozilla/activity-stream/issues/1311
+     *
+     * @param usePath Use the path of the URL to extract a label (if suitable)
+     */
+    public static void extractLabel(final Context context, final String url, final boolean usePath, final LabelCallback callback) {
+        new AsyncTask<Void, Void, String>() {
+            @Override
+            protected String doInBackground(Void... params) {
+                if (TextUtils.isEmpty(url)) {
+                    return "";
+                }
+
+                final Uri uri = Uri.parse(url);
+
+                // Use last path segment if suitable
+                if (usePath) {
+                    final String segment = uri.getLastPathSegment();
+                    if (!TextUtils.isEmpty(segment)
+                            && !UNDESIRED_LABELS.contains(segment)
+                            && !segment.matches("^[0-9]+$")) {
+
+                        boolean hasUndesiredPrefix = false;
+                        for (int i = 0; i < UNDESIRED_LABEL_PREFIXES.size(); i++) {
+                            if (segment.startsWith(UNDESIRED_LABEL_PREFIXES.get(i))) {
+                                hasUndesiredPrefix = true;
+                                break;
+                            }
+                        }
+
+                        if (!hasUndesiredPrefix) {
+                            return segment;
+                        }
+                    }
+                }
+
+                // If no usable path segment was found then use the host without public suffix and common subdomains
+                final String host = uri.getHost();
+                if (TextUtils.isEmpty(host)) {
+                    return url;
+                }
+
+                return StringUtils.stripCommonSubdomains(
+                        PublicSuffix.stripPublicSuffix(context, host));
+            }
+
+            @Override
+            protected void onPostExecute(String label) {
+                callback.onLabelExtracted(label);
+            }
+        }.execute();
+    }
+
+    public abstract static class LabelCallback {
+        public abstract void onLabelExtracted(String label);
+    }
+}