nfc: Add native NFC API definitions.

device/nfc/nfc_tag.h

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef DEVICE_NFC_NFC_TAG_H_
+#define DEVICE_NFC_NFC_TAG_H_
+
+#include "device/nfc/nfc_tag_technology.h"
+
+namespace device {
+
+// NfcTag represents a remote NFC tag. An NFC tag is a passive NFC device,
+// powered by the NFC field of the local adapter while it is in range. Tags
+// can come in many forms, such as stickers, key fobs, or even embedded in a
+// more sofisticated device.
+//
+// Tags can have a wide range of capabilities. Simple tags just offer
+// read/write semantics, and contain some one time programmable areas to make
+// read-only. More complex tags offer math operations and per-sector access
+// control and authentication. The most sophisticated tags contain operating
+// environments allowing complex interactions with the code executing on the
+// tag.
+//
+// The NfcTag class facilitates possible interactions with a tag. The most
+// common usage of a tag is to exchange NDEF messages, but different kinds of
+// I/O can be performed using the NfcTagTechnology classes.
+class NfcTag {
+ public:
+  // NFC tag types.
+  enum TagType {
+    kTagType1,
+    kTagType2,
+    kTagType3,
+    kTagType4
+  };
+
+  // NFC protocols that a tag can support. A tag will usually support only one
+  // of these.
+  enum Protocol {
+    kProtocolFelica,
+    kProtocolIsoDep,
+    kProtocolJewel,
+    kProtocolMifare,
+    kProtocolNfcDep
+  };
+
+  // Interface for observing changes from NFC tags.
+  class Observer {
+   public:
+    virtual ~Observer() {}
+
+    // This method will be called when an NDEF message |message|, stored on the
+    // NFC tag |tag| has been read. Although NDEF is the most common record
+    // storage format for NFC tags, not all tags support it. This method won't
+    // be called if there are no records on an NDEF compliant tag or if the tag
+    // doesn't support NDEF.
+    virtual void RecordsReceived(NfcTag* tag, const NfcNdefMessage& message) {}
+  };
+
+  virtual ~NfcTag();
+
+  // Adds and removes observers for events on this NFC tag. If monitoring
+  // multiple tags, check the |tag| parameter of observer methods to determine
+  // which tag is issuing the event.
+  virtual void AddObserver(Observer* observer) = 0;
+  virtual void RemoveObserver(Observer* observer) = 0;
+
+  // Returns the unique identifier assigned to this tag.
+  virtual std::string GetIdentifier() const = 0;
+
+  // Returns the current tag's NFC forum specified "type".
+  virtual TagType GetType() const = 0;
+
+  // Returns true, if this tag is read-only and cannot be written to.
+  virtual bool IsReadOnly() const = 0;
+
+  // Returns the current tag's supported NFC protocol.
+  virtual Protocol GetSupportedProtocol() const = 0;
+
+  // Returns a bitmask of the tag I/O technologies supported by this tag.
+  virtual NfcTagTechnology::TechnologyTypeMask
+      GetSupportedTechnologies() const = 0;
+
+ protected:
+  NfcTag();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(NfcTag);
+};
+
+}  // namespace device
+
+#endif  // DEVICE_NFC_NFC_TAG_H_