Add RecommendationPlugin for Cloud Print

Reuses already existing infrastructure. The mMDNSFilteredDiscovery lambda
is called for every network service that supports #PRIVET_SERVICE. Then
the plugin checks the txt fields to make sure the printer is valid. The
check is not complete but good enough to make sure this is either a
cloud print capable printer or something that tries really hard.

Test: Connected to network with three printers, 2 GCP capable. Found the
      two printers
Fixes: 35766193
Change-Id: I7c9180c8c154fa092fec5b943a94bad77da74c86

2 files changed, 178 insertions, 0 deletions

diff --git a/packages/PrintRecommendationService/src/com/android/printservice/recommendation/RecommendationServiceImpl.java b/packages/PrintRecommendationService/src/com/android/printservice/recommendation/RecommendationServiceImpl.java
index 1fe5a2a4d40b..8edd0eccf742 100644
--- a/packages/PrintRecommendationService/src/com/android/printservice/recommendation/RecommendationServiceImpl.java
+++ b/packages/PrintRecommendationService/src/com/android/printservice/recommendation/RecommendationServiceImpl.java
@@ -21,6 +21,8 @@ import android.printservice.recommendation.RecommendationInfo;
 import android.printservice.recommendation.RecommendationService;
 import android.printservice.PrintService;
 import android.util.Log;
+
+import com.android.printservice.recommendation.plugin.google.CloudPrintPlugin;
 import com.android.printservice.recommendation.plugin.hp.HPRecommendationPlugin;
 import com.android.printservice.recommendation.plugin.mdnsFilter.MDNSFilterPlugin;
 import com.android.printservice.recommendation.plugin.mdnsFilter.VendorConfig;
@@ -61,6 +63,14 @@ public class RecommendationServiceImpl extends RecommendationService
         }
 
         try {
+            mPlugins.add(new RemotePrintServicePlugin(new CloudPrintPlugin(this), this,
+                    true));
+        } catch (Exception e) {
+            Log.e(LOG_TAG, "Could not initiate "
+                            + getString(R.string.plugin_vendor_google_cloud_print) + " plugin", e);
+        }
+
+        try {
             mPlugins.add(new RemotePrintServicePlugin(new HPRecommendationPlugin(this), this,
                     false));
         } catch (Exception e) {
diff --git a/packages/PrintRecommendationService/src/com/android/printservice/recommendation/plugin/google/CloudPrintPlugin.java b/packages/PrintRecommendationService/src/com/android/printservice/recommendation/plugin/google/CloudPrintPlugin.java
new file mode 100644
index 000000000000..05b0c862ebd5
--- /dev/null
+++ b/packages/PrintRecommendationService/src/com/android/printservice/recommendation/plugin/google/CloudPrintPlugin.java
@@ -0,0 +1,168 @@
+/*
+ * Copyright (C) 2017 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.google;
+
+import static com.android.printservice.recommendation.util.MDNSUtils.ATTRIBUTE_TY;
+
+import android.annotation.NonNull;
+import android.annotation.StringRes;
+import android.content.Context;
+import android.util.ArrayMap;
+import android.util.Log;
+
+import com.android.printservice.recommendation.PrintServicePlugin;
+import com.android.printservice.recommendation.R;
+import com.android.printservice.recommendation.util.MDNSFilteredDiscovery;
+
+import java.net.Inet4Address;
+import java.net.InetAddress;
+import java.nio.charset.StandardCharsets;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Plugin detecting <a href="https://developers.google.com/cloud-print/docs/privet">Google Cloud
+ * Print</a> printers.
+ */
+public class CloudPrintPlugin implements PrintServicePlugin {
+    private static final String LOG_TAG = CloudPrintPlugin.class.getSimpleName();
+    private static final boolean DEBUG = false;
+
+    private static final String ATTRIBUTE_TXTVERS = "txtvers";
+    private static final String ATTRIBUTE_URL = "url";
+    private static final String ATTRIBUTE_TYPE = "type";
+    private static final String ATTRIBUTE_ID = "id";
+    private static final String ATTRIBUTE_CS = "cs";
+
+    private static final String TYPE = "printer";
+
+    private static final String PRIVET_SERVICE = "_privet._tcp";
+
+    /** The required mDNS service types */
+    private static final Set<String> PRINTER_SERVICE_TYPE = new HashSet<String>() {{
+        // Not checking _printer_._sub
+        add(PRIVET_SERVICE);
+    }};
+
+    /** All possible connection states */
+    private static final Set<String> POSSIBLE_CONNECTION_STATES = new HashSet<String>() {{
+        add("online");
+        add("offline");
+        add("connecting");
+        add("not-configured");
+    }};
+
+    private static final byte SUPPORTED_TXTVERS = '1';
+
+    /** The mDNS filtered discovery */
+    private final MDNSFilteredDiscovery mMDNSFilteredDiscovery;
+
+    /**
+     * Create a plugin detecting Google Cloud Print printers.
+     *
+     * @param context The context the plugin runs in
+     */
+    public CloudPrintPlugin(@NonNull Context context) {
+        mMDNSFilteredDiscovery = new MDNSFilteredDiscovery(context, PRINTER_SERVICE_TYPE,
+                nsdServiceInfo -> {
+                    // The attributes are case insensitive. For faster searching create a clone of
+                    // the map with the attribute-keys all in lower case.
+                    ArrayMap<String, byte[]> caseInsensitiveAttributes =
+                            new ArrayMap<>(nsdServiceInfo.getAttributes().size());
+                    for (Map.Entry<String, byte[]> entry : nsdServiceInfo.getAttributes()
+                            .entrySet()) {
+                        caseInsensitiveAttributes.put(entry.getKey().toLowerCase(),
+                                entry.getValue());
+                    }
+
+                    if (DEBUG) {
+                        Log.i(LOG_TAG, nsdServiceInfo.getServiceName() + ":");
+                        Log.i(LOG_TAG, "type:  " + nsdServiceInfo.getServiceType());
+                        Log.i(LOG_TAG, "host:  " + nsdServiceInfo.getHost());
+                        for (Map.Entry<String, byte[]> entry : caseInsensitiveAttributes.entrySet()) {
+                            if (entry.getValue() == null) {
+                                Log.i(LOG_TAG, entry.getKey() + "= null");
+                            } else {
+                                Log.i(LOG_TAG, entry.getKey() + "=" + new String(entry.getValue(),
+                                        StandardCharsets.UTF_8));
+                            }
+                        }
+                    }
+
+                    byte[] txtvers = caseInsensitiveAttributes.get(ATTRIBUTE_TXTVERS);
+                    if (txtvers == null || txtvers.length != 1 || txtvers[0] != SUPPORTED_TXTVERS) {
+                        // The spec requires this to be the first attribute, but at this time we
+                        // lost the order of the attributes
+                        return false;
+                    }
+
+                    if (caseInsensitiveAttributes.get(ATTRIBUTE_TY) == null) {
+                        return false;
+                    }
+
+                    byte[] url = caseInsensitiveAttributes.get(ATTRIBUTE_URL);
+                    if (url == null || url.length == 0) {
+                        return false;
+                    }
+
+                    byte[] type = caseInsensitiveAttributes.get(ATTRIBUTE_TYPE);
+                    if (type == null || !TYPE.equals(
+                            new String(type, StandardCharsets.UTF_8).toLowerCase())) {
+                        return false;
+                    }
+
+                    if (caseInsensitiveAttributes.get(ATTRIBUTE_ID) == null) {
+                        return false;
+                    }
+
+                    byte[] cs = caseInsensitiveAttributes.get(ATTRIBUTE_CS);
+                    if (cs == null || !POSSIBLE_CONNECTION_STATES.contains(
+                            new String(cs, StandardCharsets.UTF_8).toLowerCase())) {
+                        return false;
+                    }
+
+                    InetAddress address = nsdServiceInfo.getHost();
+                    if (!(address instanceof Inet4Address)) {
+                        // Not checking for link local address
+                        return false;
+                    }
+
+                    return true;
+                });
+    }
+
+    @Override
+    @NonNull public CharSequence getPackageName() {
+        return "com.google.android.apps.cloudprint";
+    }
+
+    @Override
+    public void start(@NonNull PrinterDiscoveryCallback callback) throws Exception {
+        mMDNSFilteredDiscovery.start(callback);
+    }
+
+    @Override
+    @StringRes public int getName() {
+        return R.string.plugin_vendor_google_cloud_print;
+    }
+
+    @Override
+    public void stop() throws Exception {
+        mMDNSFilteredDiscovery.stop();
+    }
+}