notification ranking infrastructure

Added an ordered list of notifications (n.b. a complete ordering).
Added a mechanism for ranking to be updated asynchronously
Added onNotificationRankingUpdate to NotificationListeners
Added an opaque order update object and a convenience comparator that
  uses it to sort notifications for listeners

Repurpose scorers to be ranking preprocessors.  The preprocessors will
perform heavy-weight validation of the notification object and memoize
the results to improve efficiency of the ranking comparator.

Current internal comparator implements status quo ordering, except
that notes with a valid contact sort to the top of their priority
bucket.

Change-Id: I7244c65944a9657df41fb313b3cb5a52e149709d
diff --git a/services/core/java/com/android/server/notification/ValidateNotificationPeople.java b/services/core/java/com/android/server/notification/ValidateNotificationPeople.java
new file mode 100644
index 0000000..8cd2f9b2
--- /dev/null
+++ b/services/core/java/com/android/server/notification/ValidateNotificationPeople.java
@@ -0,0 +1,298 @@
+/*
+* Copyright (C) 2014 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.server.notification;
+
+import android.app.Notification;
+import android.content.Context;
+import android.database.Cursor;
+import android.net.Uri;
+import android.os.Bundle;
+import android.provider.ContactsContract;
+import android.provider.ContactsContract.Contacts;
+import android.provider.Settings;
+import android.text.TextUtils;
+import android.util.LruCache;
+import android.util.Slog;
+
+import com.android.server.notification.NotificationManagerService.NotificationRecord;
+
+import java.util.ArrayList;
+import java.util.LinkedList;
+
+/**
+ * This {@link NotificationSignalExtractor} attempts to validate
+ * people references. Also elevates the priority of real people.
+ */
+public class ValidateNotificationPeople implements NotificationSignalExtractor {
+    private static final String TAG = "ValidateNotificationPeople";
+    private static final boolean INFO = true;
+    private static final boolean DEBUG = false;
+
+    private static final boolean ENABLE_PEOPLE_VALIDATOR = true;
+    private static final String SETTING_ENABLE_PEOPLE_VALIDATOR =
+            "validate_notification_people_enabled";
+    private static final String[] LOOKUP_PROJECTION = { Contacts._ID };
+    private static final int MAX_PEOPLE = 10;
+    private static final int PEOPLE_CACHE_SIZE = 200;
+
+    private static final float NONE = 0f;
+    private static final float VALID_CONTACT = 0.5f;
+    // TODO private static final float STARRED_CONTACT = 1f;
+
+    protected boolean mEnabled;
+    private Context mContext;
+
+    // maps raw person handle to resolved person object
+    private LruCache<String, LookupResult> mPeopleCache;
+
+    private RankingFuture validatePeople(NotificationRecord record) {
+        float affinity = NONE;
+        Bundle extras = record.getNotification().extras;
+        if (extras == null) {
+            return null;
+        }
+
+        final String[] people = getExtraPeople(extras);
+        if (people == null || people.length == 0) {
+            return null;
+        }
+
+        if (INFO) Slog.i(TAG, "Validating: " + record.sbn.getKey());
+        final LinkedList<String> pendingLookups = new LinkedList<String>();
+        for (int personIdx = 0; personIdx < people.length && personIdx < MAX_PEOPLE; personIdx++) {
+            final String handle = people[personIdx];
+            if (TextUtils.isEmpty(handle)) continue;
+
+            synchronized (mPeopleCache) {
+                LookupResult lookupResult = mPeopleCache.get(handle);
+                if (lookupResult == null || lookupResult.isExpired()) {
+                    pendingLookups.add(handle);
+                } else {
+                    if (DEBUG) Slog.d(TAG, "using cached lookupResult: " + lookupResult.mId);
+                }
+                if (lookupResult != null) {
+                    affinity = Math.max(affinity, lookupResult.getAffinity());
+                }
+            }
+        }
+
+        // record the best available data, so far:
+        record.setContactAffinity(affinity);
+
+        if (pendingLookups.isEmpty()) {
+            if (INFO) Slog.i(TAG, "final affinity: " + affinity);
+            return null;
+        }
+
+        if (DEBUG) Slog.d(TAG, "Pending: future work scheduled for: " + record.sbn.getKey());
+        return new RankingFuture(record) {
+            @Override
+            public void work() {
+                if (INFO) Slog.i(TAG, "Executing: validation for: " + mRecord.sbn.getKey());
+                float affinity = NONE;
+                LookupResult lookupResult = null;
+                for (final String handle: pendingLookups) {
+                    final Uri uri = Uri.parse(handle);
+                    if ("tel".equals(uri.getScheme())) {
+                        if (DEBUG) Slog.d(TAG, "checking telephone URI: " + handle);
+                        lookupResult = resolvePhoneContact(handle, uri.getSchemeSpecificPart());
+                    } else if (handle.startsWith(Contacts.CONTENT_LOOKUP_URI.toString())) {
+                        if (DEBUG) Slog.d(TAG, "checking lookup URI: " + handle);
+                        lookupResult = resolveContactsUri(handle, uri);
+                    } else {
+                        Slog.w(TAG, "unsupported URI " + handle);
+                    }
+                }
+                if (lookupResult != null) {
+                    affinity = Math.max(affinity, lookupResult.getAffinity());
+                }
+
+                float affinityBound = mRecord.getContactAffinity();
+                affinity = Math.max(affinity, affinityBound);
+                mRecord.setContactAffinity(affinity);
+                if (INFO) Slog.i(TAG, "final affinity: " + affinity);
+            }
+        };
+    }
+
+    private String[] getExtraPeople(Bundle extras) {
+        String[] people = extras.getStringArray(Notification.EXTRA_PEOPLE);
+        if (people != null) {
+            return people;
+        }
+
+        ArrayList<String> stringArray = extras.getStringArrayList(Notification.EXTRA_PEOPLE);
+        if (stringArray != null) {
+            return (String[]) stringArray.toArray();
+        }
+
+        String string = extras.getString(Notification.EXTRA_PEOPLE);
+        if (string != null) {
+            people = new String[1];
+            people[0] = string;
+            return people;
+        }
+        char[] charArray = extras.getCharArray(Notification.EXTRA_PEOPLE);
+        if (charArray != null) {
+            people = new String[1];
+            people[0] = new String(charArray);
+            return people;
+        }
+
+        CharSequence charSeq = extras.getCharSequence(Notification.EXTRA_PEOPLE);
+        if (charSeq != null) {
+            people = new String[1];
+            people[0] = charSeq.toString();
+            return people;
+        }
+
+        CharSequence[] charSeqArray = extras.getCharSequenceArray(Notification.EXTRA_PEOPLE);
+        if (charSeqArray != null) {
+            final int N = charSeqArray.length;
+            people = new String[N];
+            for (int i = 0; i < N; i++) {
+                people[i] = charSeqArray[i].toString();
+            }
+            return people;
+        }
+
+        ArrayList<CharSequence> charSeqList =
+                extras.getCharSequenceArrayList(Notification.EXTRA_PEOPLE);
+        if (charSeqList != null) {
+            final int N = charSeqList.size();
+            people = new String[N];
+            for (int i = 0; i < N; i++) {
+                people[i] = charSeqList.get(i).toString();
+            }
+            return people;
+        }
+        return null;
+    }
+
+    private LookupResult resolvePhoneContact(final String handle, final String number) {
+        LookupResult lookupResult = null;
+        Cursor c = null;
+        try {
+            Uri numberUri = Uri.withAppendedPath(ContactsContract.PhoneLookup.CONTENT_FILTER_URI,
+                    Uri.encode(number));
+            c = mContext.getContentResolver().query(numberUri, LOOKUP_PROJECTION, null, null, null);
+            if (c != null && c.getCount() > 0) {
+                c.moveToFirst();
+                final int idIdx = c.getColumnIndex(Contacts._ID);
+                final int id = c.getInt(idIdx);
+                if (DEBUG) Slog.d(TAG, "is valid: " + id);
+                lookupResult = new LookupResult(id);
+            }
+        } catch(Throwable t) {
+            Slog.w(TAG, "Problem getting content resolver or performing contacts query.", t);
+        } finally {
+            if (c != null) {
+                c.close();
+            }
+        }
+        if (lookupResult == null) {
+            lookupResult = new LookupResult(LookupResult.INVALID_ID);
+        }
+        synchronized (mPeopleCache) {
+            mPeopleCache.put(handle, lookupResult);
+        }
+        return lookupResult;
+    }
+
+    private LookupResult resolveContactsUri(String handle, final Uri personUri) {
+        LookupResult lookupResult = null;
+        Cursor c = null;
+        try {
+            c = mContext.getContentResolver().query(personUri, LOOKUP_PROJECTION, null, null, null);
+            if (c != null && c.getCount() > 0) {
+                c.moveToFirst();
+                final int idIdx = c.getColumnIndex(Contacts._ID);
+                final int id = c.getInt(idIdx);
+                if (DEBUG) Slog.d(TAG, "is valid: " + id);
+                lookupResult = new LookupResult(id);
+            }
+        } catch(Throwable t) {
+            Slog.w(TAG, "Problem getting content resolver or performing contacts query.", t);
+        } finally {
+            if (c != null) {
+                c.close();
+            }
+        }
+        if (lookupResult == null) {
+            lookupResult = new LookupResult(LookupResult.INVALID_ID);
+        }
+        synchronized (mPeopleCache) {
+            mPeopleCache.put(handle, lookupResult);
+        }
+        return lookupResult;
+    }
+
+    public void initialize(Context context) {
+        if (DEBUG) Slog.d(TAG, "Initializing  " + getClass().getSimpleName() + ".");
+        mContext = context;
+        mPeopleCache = new LruCache<String, LookupResult>(PEOPLE_CACHE_SIZE);
+        mEnabled = ENABLE_PEOPLE_VALIDATOR && 1 == Settings.Global.getInt(
+                mContext.getContentResolver(), SETTING_ENABLE_PEOPLE_VALIDATOR, 1);
+    }
+
+    public RankingFuture process(NotificationManagerService.NotificationRecord record) {
+        if (!mEnabled) {
+            if (INFO) Slog.i(TAG, "disabled");
+            return null;
+        }
+        if (record == null || record.getNotification() == null) {
+            if (INFO) Slog.i(TAG, "skipping empty notification");
+            return null;
+        }
+        return validatePeople(record);
+    }
+
+    private static class LookupResult {
+        private static final long CONTACT_REFRESH_MILLIS = 60 * 60 * 1000;  // 1hr
+        public static final int INVALID_ID = -1;
+
+        private final long mExpireMillis;
+        private int mId;
+
+        public LookupResult(int id) {
+            mId = id;
+            mExpireMillis = System.currentTimeMillis() + CONTACT_REFRESH_MILLIS;
+        }
+
+        public boolean isExpired() {
+            return mExpireMillis < System.currentTimeMillis();
+        }
+
+        public boolean isInvalid() {
+            return mId == INVALID_ID || isExpired();
+        }
+
+        public float getAffinity() {
+            if (isInvalid()) {
+                return NONE;
+            } else {
+                return VALID_CONTACT;  // TODO: finer grained result: stars
+            }
+        }
+
+        public LookupResult setId(int id) {
+            mId = id;
+            return this;
+        }
+    }
+}
+