From f3ebf77ed21d2c9ab4b65f8bd4fba2815119943b Mon Sep 17 00:00:00 2001
From: Anay Wadhera <awadhera@google.com>
Date: Thu, 23 Feb 2023 12:52:57 -0800
Subject: [PATCH] Add GattClient#SetCharacteristicNotification for subscribing
 to a GATT characteristic

PiperOrigin-RevId: 511862183
---
 internal/platform/implementation/apple/ble.h  |  3 +++
 internal/platform/implementation/apple/ble.mm |  6 ++++++
 internal/platform/implementation/ble_v2.h     | 11 +++++++++++
 internal/platform/implementation/g3/ble_v2.cc |  7 +++++++
 internal/platform/implementation/g3/ble_v2.h  |  4 ++++
 5 files changed, 31 insertions(+)

diff --git a/internal/platform/implementation/apple/ble.h b/internal/platform/implementation/apple/ble.h
index ca734824..a2b7c5ae 100644
--- a/internal/platform/implementation/apple/ble.h
+++ b/internal/platform/implementation/apple/ble.h
@@ -184,6 +184,9 @@ class BleMedium : public api::ble_v2::BleMedium {
     bool WriteCharacteristic(const api::ble_v2::GattCharacteristic &characteristic,
                              const ByteArray &value) override;
 
+    bool SetCharacteristicNotification(const api::ble_v2::GattCharacteristic &characteristic,
+                                       bool enable) override;
+
     void Disconnect() override;
 
    private:
diff --git a/internal/platform/implementation/apple/ble.mm b/internal/platform/implementation/apple/ble.mm
index 8fb5c74b..ee388125 100644
--- a/internal/platform/implementation/apple/ble.mm
+++ b/internal/platform/implementation/apple/ble.mm
@@ -585,6 +585,12 @@ bool BleMedium::GattClient::WriteCharacteristic(
   return false;
 }
 
+bool BleMedium::GattClient::SetCharacteristicNotification(
+    const api::ble_v2::GattCharacteristic& characteristic, bool enable) {
+  // No op since we can't write characteristics.
+  return false;
+}
+
 void BleMedium::GattClient::Disconnect() {
   [central_ disconnectGattServiceWithPeripheralID:ObjCStringFromCppString(peripheral_id_)];
 }
diff --git a/internal/platform/implementation/ble_v2.h b/internal/platform/implementation/ble_v2.h
index fa128220..d7a41098 100644
--- a/internal/platform/implementation/ble_v2.h
+++ b/internal/platform/implementation/ble_v2.h
@@ -25,6 +25,7 @@
 #include <vector>
 
 #include "absl/container/flat_hash_map.h"
+#include "absl/functional/any_invocable.h"
 #include "absl/status/status.h"
 #include "absl/strings/string_view.h"
 #include "internal/platform/byte_array.h"
@@ -180,6 +181,12 @@ class GattClient {
   virtual bool WriteCharacteristic(const GattCharacteristic& characteristic,
                                    const ByteArray& value) = 0;
 
+  // https://developer.android.com/reference/android/bluetooth/BluetoothGatt.html#setCharacteristicNotification(android.bluetooth.BluetoothGattCharacteristic,%20boolean)
+  //
+  // Enable or disable notifications/indications for a given characteristic.
+  virtual bool SetCharacteristicNotification(
+      const GattCharacteristic& characteristic, bool enable) = 0;
+
   // https://developer.android.com/reference/android/bluetooth/BluetoothGatt.html#disconnect()
   virtual void Disconnect() = 0;
 };
@@ -223,6 +230,10 @@ class GattServer {
 // Callback for asynchronous events on the client side of a GATT connection.
 struct ClientGattConnectionCallback {
  public:
+  // Called when the characteristic is changed
+  absl::AnyInvocable<void(const GattCharacteristic& characteristic)>
+      on_characteristic_changed_cb = [](const GattCharacteristic&) {};
+
   // Called when the client is disconnected from the GATT server.
   absl::AnyInvocable<void()> disconnected_cb = []() {};
 };
diff --git a/internal/platform/implementation/g3/ble_v2.cc b/internal/platform/implementation/g3/ble_v2.cc
index 1689f8d2..80b92d85 100644
--- a/internal/platform/implementation/g3/ble_v2.cc
+++ b/internal/platform/implementation/g3/ble_v2.cc
@@ -20,6 +20,7 @@
 #include <optional>
 #include <string>
 #include <utility>
+#include <vector>
 
 #include "absl/status/status.h"
 #include "absl/strings/escaping.h"
@@ -452,6 +453,12 @@ bool BleV2Medium::GattClient::WriteCharacteristic(
   return false;
 }
 
+bool BleV2Medium::GattClient::SetCharacteristicNotification(
+    const api::ble_v2::GattCharacteristic& characteristic, bool enable) {
+  // No op since we can't write characteristics.
+  return false;
+}
+
 void BleV2Medium::GattClient::Disconnect() {
   absl::MutexLock lock(&mutex_);
   NEARBY_LOGS(INFO) << "G3 Ble GattClient Disconnect";
diff --git a/internal/platform/implementation/g3/ble_v2.h b/internal/platform/implementation/g3/ble_v2.h
index 6e9e79f6..ccf86551 100644
--- a/internal/platform/implementation/g3/ble_v2.h
+++ b/internal/platform/implementation/g3/ble_v2.h
@@ -240,6 +240,10 @@ class BleV2Medium : public api::ble_v2::BleMedium {
         const api::ble_v2::GattCharacteristic& characteristic,
         const ByteArray& value) override;
 
+    bool SetCharacteristicNotification(
+        const api::ble_v2::GattCharacteristic& characteristic,
+        bool enable) override;
+
     void Disconnect() override;
 
    private: