/*
* Copyright (C) 2016 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.printservice.recommendation.plugin.mdnsFilter;
import android.annotation.NonNull;
import android.annotation.Nullable;
import android.content.Context;
import android.content.res.XmlResourceParser;
import android.util.ArrayMap;
import com.android.internal.annotations.Immutable;
import com.android.internal.util.Preconditions;
import com.android.printservice.recommendation.R;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
/**
* Vendor configuration as read from {@link R.xml#vendorconfigs vendorconfigs.xml}. Configuration
* can be read via {@link #getConfig(Context, String)}.
*/
@Immutable
public class VendorConfig {
/** Lock for {@link #sConfigs} */
private static final Object sLock = new Object();
/** Strings used as XML tags */
private static final String VENDORS_TAG = "vendors";
private static final String VENDOR_TAG = "vendor";
private static final String NAME_TAG = "name";
private static final String PACKAGE_TAG = "package";
private static final String MDNSNAMES_TAG = "mdns-names";
private static final String MDNSNAME_TAG = "mdns-name";
/** Map from vendor name to config. Initialized on first {@link #getConfig use}. */
private static @Nullable ArrayMap<String, VendorConfig> sConfigs;
/** Localized vendor name */
public final @NonNull String name;
/** Package name containing the print service for this vendor */
public final @NonNull String packageName;
/** mDNS names used by this vendor */
public final @NonNull List<String> mDNSNames;
/**
* Create an immutable configuration.
*/
private VendorConfig(@NonNull String name, @NonNull String packageName,
@NonNull List<String> mDNSNames) {
this.name = Preconditions.checkStringNotEmpty(name);
this.packageName = Preconditions.checkStringNotEmpty(packageName);
this.mDNSNames = Preconditions.checkCollectionElementsNotNull(mDNSNames, "mDNSName");
}
/**
* Get the configuration for a vendor.
*
* @param context Calling context
* @param name The name of the config to read
*
* @return the config for the vendor or null if not found
*
* @throws IOException
* @throws XmlPullParserException
*/
public static @Nullable VendorConfig getConfig(@NonNull Context context, @NonNull String name)
throws IOException, XmlPullParserException {
synchronized (sLock) {
if (sConfigs == null) {
sConfigs = readVendorConfigs(context);
}
return sConfigs.get(name);
}
}
/**
* Get all known vendor configurations.
*
* @param context Calling context
*
* @return The known configurations
*
* @throws IOException
* @throws XmlPullParserException
*/
public static @NonNull Collection<VendorConfig> getAllConfigs(@NonNull Context context)
throws IOException, XmlPullParserException {
synchronized (sLock) {
if (sConfigs == null) {
sConfigs = readVendorConfigs(context);
}
return sConfigs.values();
}
}
/**
* Read the text from a XML tag.
*
* @param parser XML parser to read from
*
* @return The text or "" if no text was found
*
* @throws IOException
* @throws XmlPullParserException
*/
private static @NonNull String readText(XmlPullParser parser)
throws IOException, XmlPullParserException {
String result = "";
if (parser.next() == XmlPullParser.TEXT) {
result = parser.getText();
parser.nextTag();
}
return result;
}
/**
* Read a tag with a text content from the parser.
*
* @param parser XML parser to read from
* @param tagName The name of the tag to read
*
* @return The text content of the tag
*
* @throws IOException
* @throws XmlPullParserException
*/
private static @NonNull String readSimpleTag(@NonNull Context context,
@NonNull XmlPullParser parser, @NonNull String tagName, boolean resolveReferences)
throws IOException, XmlPullParserException {
parser.require(XmlPullParser.START_TAG, null, tagName);
String text = readText(parser);
parser.require(XmlPullParser.END_TAG, null, tagName);
if (resolveReferences && text.startsWith("@")) {
return context.getResources().getString(
context.getResources().getIdentifier(text, null, context.getPackageName()));
} else {
return text;
}
}
/**
* Read content of a list of tags.
*
* @param parser XML parser to read from
* @param tagName The name of the list tag
* @param subTagName The name of the list-element tags
* @param tagReader The {@link TagReader reader} to use to read the tag content
* @param <T> The type of the parsed tag content
*
* @return A list of {@link T}
*
* @throws XmlPullParserException
* @throws IOException
*/
private static @NonNull <T> ArrayList<T> readTagList(@NonNull XmlPullParser parser,
@NonNull String tagName, @NonNull String subTagName, @NonNull TagReader<T> tagReader)
throws XmlPullParserException, IOException {
ArrayList<T> entries = new ArrayList<>();
parser.require(XmlPullParser.START_TAG, null, tagName);
while (parser.next() != XmlPullParser.END_TAG) {
if (parser.getEventType() != XmlPullParser.START_TAG) {
continue;
}
if (parser.getName().equals(subTagName)) {
entries.add(tagReader.readTag(parser, subTagName));
} else {
throw new XmlPullParserException(
"Unexpected subtag of " + tagName + ": " + parser.getName());
}
}
return entries;
}
/**
* Read the vendor configuration file.
*
* @param context The content issuing the read
*
* @return An map pointing from vendor name to config
*
* @throws IOException
* @throws XmlPullParserException
*/
private static @NonNull ArrayMap<String, VendorConfig> readVendorConfigs(
@NonNull final Context context) throws IOException, XmlPullParserException {
try (XmlResourceParser parser = context.getResources().getXml(R.xml.vendorconfigs)) {
// Skip header
int parsingEvent;
do {
parsingEvent = parser.next();
} while (parsingEvent != XmlResourceParser.START_TAG);
ArrayList<VendorConfig> configs = readTagList(parser, VENDORS_TAG, VENDOR_TAG,
new TagReader<VendorConfig>() {
public VendorConfig readTag(XmlPullParser parser, String tagName)
throws XmlPullParserException, IOException {
return readVendorConfig(context, parser, tagName);
}
});
ArrayMap<String, VendorConfig> configMap = new ArrayMap<>(configs.size());
final int numConfigs = configs.size();
for (int i = 0; i < numConfigs; i++) {
VendorConfig config = configs.get(i);
configMap.put(config.name, config);
}
return configMap;
}
}
/**
* Read a single vendor configuration.
*
* @param parser XML parser to read from
* @param tagName The vendor tag
* @param context Calling context
*
* @return A config
*
* @throws XmlPullParserException
* @throws IOException
*/
private static VendorConfig readVendorConfig(@NonNull final Context context,
@NonNull XmlPullParser parser, @NonNull String tagName) throws XmlPullParserException,
IOException {
parser.require(XmlPullParser.START_TAG, null, tagName);
String name = null;
String packageName = null;
List<String> mDNSNames = null;
while (parser.next() != XmlPullParser.END_TAG) {
if (parser.getEventType() != XmlPullParser.START_TAG) {
continue;
}
String subTagName = parser.getName();
switch (subTagName) {
case NAME_TAG:
name = readSimpleTag(context, parser, NAME_TAG, false);
break;
case PACKAGE_TAG:
packageName = readSimpleTag(context, parser, PACKAGE_TAG, true);
break;
case MDNSNAMES_TAG:
mDNSNames = readTagList(parser, MDNSNAMES_TAG, MDNSNAME_TAG,
new TagReader<String>() {
public String readTag(XmlPullParser parser, String tagName)
throws XmlPullParserException, IOException {
return readSimpleTag(context, parser, tagName, true);
}
}
);
break;
default:
throw new XmlPullParserException("Unexpected subtag of " + tagName + ": "
+ subTagName);
}
}
if (name == null) {
throw new XmlPullParserException("name is required");
}
if (packageName == null) {
throw new XmlPullParserException("package is required");
}
if (mDNSNames == null) {
mDNSNames = Collections.emptyList();
}
// A vendor config should be immutable
mDNSNames = Collections.unmodifiableList(mDNSNames);
return new VendorConfig(name, packageName, mDNSNames);
}
@Override
public String toString() {
return name + " -> " + packageName + ", " + mDNSNames;
}
/**
* Used a a "function pointer" when reading a tag in {@link #readTagList(XmlPullParser, String,
* String, TagReader)}.
*
* @param <T> The type of content to read
*/
private interface TagReader<T> {
T readTag(XmlPullParser parser, String tagName) throws XmlPullParserException, IOException;
}
}