potter: import some cmhw features

Change-Id: I20278917c6016e102ed8ef8d9b043c5ac4159274

cmhw/org/cyanogenmod/hardware/UniqueDeviceId.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2016 The CyanogenMod 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 org.cyanogenmod.hardware;
+
+import android.util.Log;
+
+import org.cyanogenmod.internal.util.FileUtils;
+
+/**
+ * Generate a unique but deterministic ID for this hardware, based on unchangeable
+ * hardware serial numbers.
+ */
+public class UniqueDeviceId {
+
+    private static final String TAG = "UniqueDeviceId";
+
+    private static final int TYPE_MMC0_CID = 0;
+
+    private static String sUniqueId = null;
+
+    private static final String MMC_TYPE = "/sys/block/mmcblk0/device/type";
+    private static final String MMC_CID  = "/sys/block/mmcblk0/device/cid";
+
+    /**
+     * Whether device supports reporting a unique device id.
+     *
+     * @return boolean Supported devices must return always true
+     */
+    public static boolean isSupported() {
+        return FileUtils.isFileReadable(MMC_TYPE) &&
+               FileUtils.isFileReadable(MMC_CID) &&
+               getUniqueDeviceIdInternal() != null;
+    }
+
+    /**
+     * This method retreives a unique ID for the device.
+     *
+     * @return String The unique device ID
+     */
+    public static String getUniqueDeviceId() {
+        return getUniqueDeviceIdInternal();
+    }
+
+    private static String getUniqueDeviceIdInternal() {
+        if (sUniqueId != null) {
+            return sUniqueId;
+        }
+
+        try {
+            String sMmcType = FileUtils.readOneLine(MMC_TYPE);
+            String sCid = FileUtils.readOneLine(MMC_CID);
+            if ("MMC".equals(sMmcType) && sCid != null) {
+                sCid = sCid.trim();
+                if (sCid.length() == 32) {
+                    sUniqueId = String.format("%03x00000%32s", TYPE_MMC0_CID, sCid);
+                    return sUniqueId;
+                }
+            }
+        } catch (Exception e) {
+            Log.e(TAG, "Failed to get unique device ID: " + e.getMessage());
+            return null;
+        }
+
+        /* Any additional types should be added here. */
+
+        return null;
+    }
+}