Asaf Rosenfeld | a5dfba1 | 2017-03-23 13:18:34 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2017 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package com.android.car; |
| 18 | |
| 19 | import android.car.annotation.FutureFeature; |
| 20 | import android.car.vms.VmsLayer; |
| 21 | import android.car.vms.VmsLayerDependency; |
| 22 | import android.car.vms.VmsLayersOffering; |
| 23 | import android.util.Log; |
| 24 | import com.android.internal.annotations.GuardedBy; |
| 25 | import java.util.ArrayList; |
| 26 | import java.util.Collection; |
| 27 | import java.util.Collections; |
| 28 | import java.util.HashMap; |
| 29 | import java.util.HashSet; |
| 30 | import java.util.List; |
| 31 | import java.util.Map; |
| 32 | import java.util.Set; |
| 33 | import java.util.stream.Collectors; |
| 34 | |
| 35 | /** |
| 36 | * Manages VMS availability for layers. |
| 37 | * |
| 38 | * Each VMS publisher sets its layers offering which are a list of layers the publisher claims |
| 39 | * it might publish. VmsLayersAvailability calculates from all the offering what are the |
| 40 | * available layers. |
| 41 | */ |
| 42 | |
| 43 | @FutureFeature |
| 44 | public class VmsLayersAvailability { |
| 45 | |
| 46 | private static final boolean DBG = true; |
| 47 | private static final String TAG = "VmsLayersAvailability"; |
| 48 | |
| 49 | private final Object mLock = new Object(); |
| 50 | @GuardedBy("mLock") |
| 51 | private final Map<VmsLayer, Set<Set<VmsLayer>>> mPotentialLayersAndDependencies = |
| 52 | new HashMap<>(); |
| 53 | @GuardedBy("mLock") |
| 54 | private final Set<VmsLayer> mCyclicAvoidanceSet = new HashSet<>(); |
| 55 | @GuardedBy("mLock") |
| 56 | private Set<VmsLayer> mAvailableLayers = Collections.EMPTY_SET; |
| 57 | @GuardedBy("mLock") |
| 58 | private Set<VmsLayer> mUnavailableLayers = Collections.EMPTY_SET; |
| 59 | |
| 60 | /** |
| 61 | * Setting the current layers offerings as reported by publishers. |
| 62 | */ |
| 63 | public void setPublishersOffering(Collection<VmsLayersOffering> publishersLayersOfferings) { |
| 64 | synchronized (mLock) { |
| 65 | reset(); |
| 66 | |
| 67 | for (VmsLayersOffering offering : publishersLayersOfferings) { |
| 68 | for (VmsLayerDependency dependency : offering.getDependencies()) { |
| 69 | VmsLayer layer = dependency.getLayer(); |
| 70 | Set<Set<VmsLayer>> curDependencies = |
| 71 | mPotentialLayersAndDependencies.get(layer); |
| 72 | if (curDependencies == null) { |
| 73 | curDependencies = new HashSet<>(); |
| 74 | mPotentialLayersAndDependencies.put(layer, curDependencies); |
| 75 | } |
| 76 | curDependencies.add(dependency.getDependencies()); |
| 77 | } |
| 78 | } |
| 79 | calculateLayers(); |
| 80 | } |
| 81 | } |
| 82 | |
| 83 | /** |
| 84 | * Returns a collection of all the layers which may be published. |
| 85 | */ |
| 86 | public Collection<VmsLayer> getAvailableLayers() { |
| 87 | synchronized (mLock) { |
| 88 | return mAvailableLayers; |
| 89 | } |
| 90 | } |
| 91 | |
| 92 | /** |
| 93 | * Returns a collection of all the layers which publishers could have published if the |
| 94 | * dependencies were satisfied. |
| 95 | */ |
| 96 | public Collection<VmsLayer> getUnavailableLayers() { |
| 97 | synchronized (mLock) { |
| 98 | return mUnavailableLayers; |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | private void reset() { |
| 103 | synchronized (mLock) { |
| 104 | mCyclicAvoidanceSet.clear(); |
| 105 | mPotentialLayersAndDependencies.clear(); |
| 106 | mAvailableLayers = Collections.EMPTY_SET; |
| 107 | mUnavailableLayers = Collections.EMPTY_SET; |
| 108 | } |
| 109 | } |
| 110 | |
| 111 | private void calculateLayers() { |
| 112 | synchronized (mLock) { |
| 113 | final Set<VmsLayer> availableLayers = new HashSet<>(); |
| 114 | |
| 115 | availableLayers.addAll( |
| 116 | mPotentialLayersAndDependencies.keySet() |
| 117 | .stream() |
| 118 | .filter(layer -> isLayerSupportedLocked(layer, availableLayers)) |
| 119 | .collect(Collectors.toSet())); |
| 120 | |
| 121 | mAvailableLayers = Collections.unmodifiableSet(availableLayers); |
| 122 | mUnavailableLayers = Collections.unmodifiableSet( |
| 123 | mPotentialLayersAndDependencies.keySet() |
| 124 | .stream() |
| 125 | .filter(layer -> !availableLayers.contains(layer)) |
| 126 | .collect(Collectors.toSet())); |
| 127 | } |
| 128 | } |
| 129 | |
| 130 | private boolean isLayerSupportedLocked(VmsLayer layer, Set<VmsLayer> currentAvailableLayers) { |
| 131 | if (DBG) { |
| 132 | Log.d(TAG, "isLayerSupported: checking layer: " + layer); |
| 133 | } |
| 134 | // If we already know that this layer is supported then we are done. |
| 135 | if (currentAvailableLayers.contains(layer)) { |
| 136 | return true; |
| 137 | } |
| 138 | // If there is no offering for this layer we're done. |
| 139 | if (!mPotentialLayersAndDependencies.containsKey(layer)) { |
| 140 | return false; |
| 141 | } |
| 142 | // Avoid cyclic dependency. |
| 143 | if (mCyclicAvoidanceSet.contains(layer)) { |
| 144 | Log.e(TAG, "Detected a cyclic dependency: " + mCyclicAvoidanceSet + " -> " + layer); |
| 145 | return false; |
| 146 | } |
| 147 | for (Set<VmsLayer> dependencies : mPotentialLayersAndDependencies.get(layer)) { |
| 148 | // If layer does not have any dependencies then add to supported. |
| 149 | if (dependencies == null || dependencies.isEmpty()) { |
| 150 | currentAvailableLayers.add(layer); |
| 151 | return true; |
| 152 | } |
| 153 | // Add the layer to cyclic avoidance set |
| 154 | mCyclicAvoidanceSet.add(layer); |
| 155 | |
| 156 | boolean isSupported = true; |
| 157 | for (VmsLayer dependency : dependencies) { |
| 158 | if (!isLayerSupportedLocked(dependency, currentAvailableLayers)) { |
| 159 | isSupported = false; |
| 160 | break; |
| 161 | } |
| 162 | } |
| 163 | mCyclicAvoidanceSet.remove(layer); |
| 164 | |
| 165 | if (isSupported) { |
| 166 | currentAvailableLayers.add(layer); |
| 167 | return true; |
| 168 | } |
| 169 | } |
| 170 | return false; |
| 171 | } |
| 172 | } |