CompanionDeviceManager

This introduces an API for apps that support companion devices to provide a
more streamlined flow for pairing and setting up the device

Bug: 30932767
Test: Using a toy app, invoke the newly introduced API (CompanionDeviceManager),
 and go through the flow. Ensure filtering works, and device is returned to
 the calling app. Ensure the calling app can pair to the selected device.
Change-Id: I0aeb653afd65e4adead13ea9c7248ec20971b04a

1 files changed, 174 insertions, 0 deletions

diff --git a/core/java/android/provider/SettingsStringUtil.java b/core/java/android/provider/SettingsStringUtil.java
new file mode 100644
index 000000000000..f242d7936776
--- /dev/null
+++ b/core/java/android/provider/SettingsStringUtil.java
@@ -0,0 +1,174 @@
+/*
+ * 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 android.provider;
+
+import android.content.ComponentName;
+import android.content.ContentResolver;
+import android.text.TextUtils;
+
+import com.android.internal.util.ArrayUtils;
+
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.function.Function;
+
+/**
+ * Utilities for dealing with {@link String} values in {@link Settings}
+ *
+ * @hide
+ */
+public class SettingsStringUtil {
+    private SettingsStringUtil() {}
+
+    public static final String DELIMITER = ":";
+
+    /**
+     * A {@link HashSet} of items, that uses a common convention of setting string
+     * serialization/deserialization of separating multiple items with {@link #DELIMITER}
+     */
+    public static abstract class ColonDelimitedSet<T> extends HashSet<T> {
+
+        public ColonDelimitedSet(String colonSeparatedItems) {
+            for (String cn :
+                    TextUtils.split(TextUtils.emptyIfNull(colonSeparatedItems), DELIMITER)) {
+                add(itemFromString(cn));
+            }
+        }
+
+        protected abstract T itemFromString(String s);
+        protected String itemToString(T item) {
+            return String.valueOf(item);
+        }
+
+        @Override
+        public String toString() {
+            StringBuilder sb = new StringBuilder();
+            Iterator<T> it = iterator();
+            if (it.hasNext()) {
+                sb.append(it.next());
+                while (it.hasNext()) {
+                    sb.append(DELIMITER);
+                    sb.append(itemToString(it.next()));
+                }
+            }
+            return sb.toString();
+        }
+
+
+        public static class OfStrings extends ColonDelimitedSet<String> {
+            public OfStrings(String colonSeparatedItems) {
+                super(colonSeparatedItems);
+            }
+
+            @Override
+            protected String itemFromString(String s) {
+                return s;
+            }
+
+            public static String add(String delimitedElements, String element) {
+                final ColonDelimitedSet<String> set
+                        = new ColonDelimitedSet.OfStrings(delimitedElements);
+                if (set.contains(element)) {
+                    return delimitedElements;
+                }
+                set.add(element);
+                return set.toString();
+            }
+
+            public static String remove(String delimitedElements, String element) {
+                final ColonDelimitedSet<String> set
+                        = new ColonDelimitedSet.OfStrings(delimitedElements);
+                if (!set.contains(element)) {
+                    return delimitedElements;
+                }
+                set.remove(element);
+                return set.toString();
+            }
+
+            public static boolean contains(String delimitedElements, String element) {
+                final String[] elements = TextUtils.split(delimitedElements, DELIMITER);
+                return ArrayUtils.indexOf(elements, element) != -1;
+            }
+        }
+    }
+
+    public static class ComponentNameSet extends ColonDelimitedSet<ComponentName> {
+        public ComponentNameSet(String colonSeparatedPackageNames) {
+            super(colonSeparatedPackageNames);
+        }
+
+        @Override
+        protected ComponentName itemFromString(String s) {
+            return ComponentName.unflattenFromString(s);
+        }
+
+        @Override
+        protected String itemToString(ComponentName item) {
+            return item.flattenToString();
+        }
+
+        public static String add(String delimitedElements, ComponentName element) {
+            final ComponentNameSet set = new ComponentNameSet(delimitedElements);
+            if (set.contains(element)) {
+                return delimitedElements;
+            }
+            set.add(element);
+            return set.toString();
+        }
+
+        public static String remove(String delimitedElements, ComponentName element) {
+            final ComponentNameSet set = new ComponentNameSet(delimitedElements);
+            if (!set.contains(element)) {
+                return delimitedElements;
+            }
+            set.remove(element);
+            return set.toString();
+        }
+
+        public static boolean contains(String delimitedElements, ComponentName element) {
+            return ColonDelimitedSet.OfStrings.contains(
+                    delimitedElements, element.flattenToString());
+        }
+    }
+
+    public static class SettingStringHelper {
+        private final ContentResolver mContentResolver;
+        private final String mSettingName;
+        private final int mUserId;
+
+        public SettingStringHelper(ContentResolver contentResolver, String name, int userId) {
+            mContentResolver = contentResolver;
+            mUserId = userId;
+            mSettingName = name;
+        }
+
+        public String read() {
+            return Settings.Secure.getStringForUser(
+                    mContentResolver, mSettingName, mUserId);
+        }
+
+        public boolean write(String value) {
+            return Settings.Secure.putStringForUser(
+                    mContentResolver, mSettingName, value, mUserId);
+        }
+
+        public boolean modify(Function<String, String> change) {
+            return write(change.apply(read()));
+        }
+    }
+}