Philip P. Moltmann | 9dcb86a | 2016-03-14 14:31:12 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2016 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.printservice.recommendation.plugin.mdnsFilter; |
| 18 | |
| 19 | import android.annotation.NonNull; |
| 20 | import android.annotation.Nullable; |
| 21 | import android.content.Context; |
| 22 | import android.content.res.XmlResourceParser; |
| 23 | import android.util.ArrayMap; |
| 24 | import com.android.internal.annotations.Immutable; |
| 25 | import com.android.internal.util.Preconditions; |
| 26 | import com.android.printservice.recommendation.R; |
| 27 | import org.xmlpull.v1.XmlPullParser; |
| 28 | import org.xmlpull.v1.XmlPullParserException; |
| 29 | |
| 30 | import java.io.IOException; |
| 31 | import java.util.ArrayList; |
| 32 | import java.util.Collection; |
| 33 | import java.util.Collections; |
| 34 | import java.util.List; |
| 35 | |
| 36 | /** |
| 37 | * Vendor configuration as read from {@link R.xml#vendorconfigs vendorconfigs.xml}. Configuration |
| 38 | * can be read via {@link #getConfig(Context, String)}. |
| 39 | */ |
| 40 | @Immutable |
| 41 | public class VendorConfig { |
| 42 | /** Lock for {@link #sConfigs} */ |
| 43 | private static final Object sLock = new Object(); |
| 44 | |
| 45 | /** Strings used as XML tags */ |
| 46 | private static final String VENDORS_TAG = "vendors"; |
| 47 | private static final String VENDOR_TAG = "vendor"; |
| 48 | private static final String NAME_TAG = "name"; |
| 49 | private static final String PACKAGE_TAG = "package"; |
| 50 | private static final String MDNSNAMES_TAG = "mdns-names"; |
| 51 | private static final String MDNSNAME_TAG = "mdns-name"; |
| 52 | |
| 53 | /** Map from vendor name to config. Initialized on first {@link #getConfig use}. */ |
| 54 | private static @Nullable ArrayMap<String, VendorConfig> sConfigs; |
| 55 | |
| 56 | /** Localized vendor name */ |
| 57 | public final @NonNull String name; |
| 58 | |
| 59 | /** Package name containing the print service for this vendor */ |
| 60 | public final @NonNull String packageName; |
| 61 | |
| 62 | /** mDNS names used by this vendor */ |
| 63 | public final @NonNull List<String> mDNSNames; |
| 64 | |
| 65 | /** |
| 66 | * Create an immutable configuration. |
| 67 | */ |
| 68 | private VendorConfig(@NonNull String name, @NonNull String packageName, |
| 69 | @NonNull List<String> mDNSNames) { |
| 70 | this.name = Preconditions.checkStringNotEmpty(name); |
| 71 | this.packageName = Preconditions.checkStringNotEmpty(packageName); |
| 72 | this.mDNSNames = Preconditions.checkCollectionElementsNotNull(mDNSNames, "mDNSName"); |
| 73 | } |
| 74 | |
| 75 | /** |
| 76 | * Get the configuration for a vendor. |
| 77 | * |
| 78 | * @param context Calling context |
| 79 | * @param name The name of the config to read |
| 80 | * |
| 81 | * @return the config for the vendor or null if not found |
| 82 | * |
| 83 | * @throws IOException |
| 84 | * @throws XmlPullParserException |
| 85 | */ |
| 86 | public static @Nullable VendorConfig getConfig(@NonNull Context context, @NonNull String name) |
| 87 | throws IOException, XmlPullParserException { |
| 88 | synchronized (sLock) { |
| 89 | if (sConfigs == null) { |
| 90 | sConfigs = readVendorConfigs(context); |
| 91 | } |
| 92 | |
| 93 | return sConfigs.get(name); |
| 94 | } |
| 95 | } |
| 96 | |
| 97 | /** |
| 98 | * Get all known vendor configurations. |
| 99 | * |
| 100 | * @param context Calling context |
| 101 | * |
| 102 | * @return The known configurations |
| 103 | * |
| 104 | * @throws IOException |
| 105 | * @throws XmlPullParserException |
| 106 | */ |
| 107 | public static @NonNull Collection<VendorConfig> getAllConfigs(@NonNull Context context) |
| 108 | throws IOException, XmlPullParserException { |
| 109 | synchronized (sLock) { |
| 110 | if (sConfigs == null) { |
| 111 | sConfigs = readVendorConfigs(context); |
| 112 | } |
| 113 | |
| 114 | return sConfigs.values(); |
| 115 | } |
| 116 | } |
| 117 | |
| 118 | /** |
| 119 | * Read the text from a XML tag. |
| 120 | * |
| 121 | * @param parser XML parser to read from |
| 122 | * |
| 123 | * @return The text or "" if no text was found |
| 124 | * |
| 125 | * @throws IOException |
| 126 | * @throws XmlPullParserException |
| 127 | */ |
| 128 | private static @NonNull String readText(XmlPullParser parser) |
| 129 | throws IOException, XmlPullParserException { |
| 130 | String result = ""; |
| 131 | |
| 132 | if (parser.next() == XmlPullParser.TEXT) { |
| 133 | result = parser.getText(); |
| 134 | parser.nextTag(); |
| 135 | } |
| 136 | |
| 137 | return result; |
| 138 | } |
| 139 | |
| 140 | /** |
| 141 | * Read a tag with a text content from the parser. |
| 142 | * |
| 143 | * @param parser XML parser to read from |
| 144 | * @param tagName The name of the tag to read |
| 145 | * |
| 146 | * @return The text content of the tag |
| 147 | * |
| 148 | * @throws IOException |
| 149 | * @throws XmlPullParserException |
| 150 | */ |
| 151 | private static @NonNull String readSimpleTag(@NonNull Context context, |
| 152 | @NonNull XmlPullParser parser, @NonNull String tagName, boolean resolveReferences) |
| 153 | throws IOException, XmlPullParserException { |
| 154 | parser.require(XmlPullParser.START_TAG, null, tagName); |
| 155 | String text = readText(parser); |
| 156 | parser.require(XmlPullParser.END_TAG, null, tagName); |
| 157 | |
| 158 | if (resolveReferences && text.startsWith("@")) { |
| 159 | return context.getResources().getString( |
| 160 | context.getResources().getIdentifier(text, null, context.getPackageName())); |
| 161 | } else { |
| 162 | return text; |
| 163 | } |
| 164 | } |
| 165 | |
| 166 | /** |
| 167 | * Read content of a list of tags. |
| 168 | * |
| 169 | * @param parser XML parser to read from |
| 170 | * @param tagName The name of the list tag |
| 171 | * @param subTagName The name of the list-element tags |
| 172 | * @param tagReader The {@link TagReader reader} to use to read the tag content |
| 173 | * @param <T> The type of the parsed tag content |
| 174 | * |
| 175 | * @return A list of {@link T} |
| 176 | * |
| 177 | * @throws XmlPullParserException |
| 178 | * @throws IOException |
| 179 | */ |
| 180 | private static @NonNull <T> ArrayList<T> readTagList(@NonNull XmlPullParser parser, |
| 181 | @NonNull String tagName, @NonNull String subTagName, @NonNull TagReader<T> tagReader) |
| 182 | throws XmlPullParserException, IOException { |
| 183 | ArrayList<T> entries = new ArrayList<>(); |
| 184 | |
| 185 | parser.require(XmlPullParser.START_TAG, null, tagName); |
| 186 | while (parser.next() != XmlPullParser.END_TAG) { |
| 187 | if (parser.getEventType() != XmlPullParser.START_TAG) { |
| 188 | continue; |
| 189 | } |
| 190 | |
| 191 | if (parser.getName().equals(subTagName)) { |
| 192 | entries.add(tagReader.readTag(parser, subTagName)); |
| 193 | } else { |
| 194 | throw new XmlPullParserException( |
| 195 | "Unexpected subtag of " + tagName + ": " + parser.getName()); |
| 196 | } |
| 197 | } |
| 198 | |
| 199 | return entries; |
| 200 | } |
| 201 | |
| 202 | /** |
| 203 | * Read the vendor configuration file. |
| 204 | * |
| 205 | * @param context The content issuing the read |
| 206 | * |
| 207 | * @return An map pointing from vendor name to config |
| 208 | * |
| 209 | * @throws IOException |
| 210 | * @throws XmlPullParserException |
| 211 | */ |
| 212 | private static @NonNull ArrayMap<String, VendorConfig> readVendorConfigs( |
| 213 | @NonNull final Context context) throws IOException, XmlPullParserException { |
| 214 | try (XmlResourceParser parser = context.getResources().getXml(R.xml.vendorconfigs)) { |
| 215 | // Skip header |
| 216 | int parsingEvent; |
| 217 | do { |
| 218 | parsingEvent = parser.next(); |
| 219 | } while (parsingEvent != XmlResourceParser.START_TAG); |
| 220 | |
| 221 | ArrayList<VendorConfig> configs = readTagList(parser, VENDORS_TAG, VENDOR_TAG, |
| 222 | new TagReader<VendorConfig>() { |
| 223 | public VendorConfig readTag(XmlPullParser parser, String tagName) |
| 224 | throws XmlPullParserException, IOException { |
| 225 | return readVendorConfig(context, parser, tagName); |
| 226 | } |
| 227 | }); |
| 228 | |
| 229 | ArrayMap<String, VendorConfig> configMap = new ArrayMap<>(configs.size()); |
| 230 | final int numConfigs = configs.size(); |
| 231 | for (int i = 0; i < numConfigs; i++) { |
| 232 | VendorConfig config = configs.get(i); |
| 233 | |
| 234 | configMap.put(config.name, config); |
| 235 | } |
| 236 | |
| 237 | return configMap; |
| 238 | } |
| 239 | } |
| 240 | |
| 241 | /** |
| 242 | * Read a single vendor configuration. |
| 243 | * |
| 244 | * @param parser XML parser to read from |
| 245 | * @param tagName The vendor tag |
| 246 | * @param context Calling context |
| 247 | * |
| 248 | * @return A config |
| 249 | * |
| 250 | * @throws XmlPullParserException |
| 251 | * @throws IOException |
| 252 | */ |
| 253 | private static VendorConfig readVendorConfig(@NonNull final Context context, |
| 254 | @NonNull XmlPullParser parser, @NonNull String tagName) throws XmlPullParserException, |
| 255 | IOException { |
| 256 | parser.require(XmlPullParser.START_TAG, null, tagName); |
| 257 | |
| 258 | String name = null; |
| 259 | String packageName = null; |
| 260 | List<String> mDNSNames = null; |
| 261 | |
| 262 | while (parser.next() != XmlPullParser.END_TAG) { |
| 263 | if (parser.getEventType() != XmlPullParser.START_TAG) { |
| 264 | continue; |
| 265 | } |
| 266 | |
| 267 | String subTagName = parser.getName(); |
| 268 | |
| 269 | switch (subTagName) { |
| 270 | case NAME_TAG: |
| 271 | name = readSimpleTag(context, parser, NAME_TAG, false); |
| 272 | break; |
| 273 | case PACKAGE_TAG: |
| 274 | packageName = readSimpleTag(context, parser, PACKAGE_TAG, true); |
| 275 | break; |
| 276 | case MDNSNAMES_TAG: |
| 277 | mDNSNames = readTagList(parser, MDNSNAMES_TAG, MDNSNAME_TAG, |
| 278 | new TagReader<String>() { |
| 279 | public String readTag(XmlPullParser parser, String tagName) |
| 280 | throws XmlPullParserException, IOException { |
| 281 | return readSimpleTag(context, parser, tagName, true); |
| 282 | } |
| 283 | } |
| 284 | ); |
| 285 | break; |
| 286 | default: |
| 287 | throw new XmlPullParserException("Unexpected subtag of " + tagName + ": " |
| 288 | + subTagName); |
| 289 | |
| 290 | } |
| 291 | } |
| 292 | |
| 293 | if (name == null) { |
| 294 | throw new XmlPullParserException("name is required"); |
| 295 | } |
| 296 | |
| 297 | if (packageName == null) { |
| 298 | throw new XmlPullParserException("package is required"); |
| 299 | } |
| 300 | |
| 301 | if (mDNSNames == null) { |
| 302 | mDNSNames = Collections.emptyList(); |
| 303 | } |
| 304 | |
| 305 | // A vendor config should be immutable |
| 306 | mDNSNames = Collections.unmodifiableList(mDNSNames); |
| 307 | |
| 308 | return new VendorConfig(name, packageName, mDNSNames); |
| 309 | } |
| 310 | |
| 311 | @Override |
| 312 | public String toString() { |
| 313 | return name + " -> " + packageName + ", " + mDNSNames; |
| 314 | } |
| 315 | |
| 316 | /** |
| 317 | * Used a a "function pointer" when reading a tag in {@link #readTagList(XmlPullParser, String, |
| 318 | * String, TagReader)}. |
| 319 | * |
| 320 | * @param <T> The type of content to read |
| 321 | */ |
| 322 | private interface TagReader<T> { |
| 323 | T readTag(XmlPullParser parser, String tagName) throws XmlPullParserException, IOException; |
| 324 | } |
| 325 | } |