From ea7aa00e0cd99a0fab900ae55e727fd5acf672fd Mon Sep 17 00:00:00 2001
From: Guogang Li <guogang@google.com>
Date: Mon, 21 Aug 2023 17:22:37 -0700
Subject: [PATCH] Avoid reading GATT server for same advertisement

PiperOrigin-RevId: 558944228
---
 .../implementation/mediums/ble_v2/BUILD       |  1 +
 .../ble_v2/discovered_peripheral_tracker.cc   | 26 ++++++++++++++++++-
 .../ble_v2/discovered_peripheral_tracker.h    |  7 +++++
 3 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/connections/implementation/mediums/ble_v2/BUILD b/connections/implementation/mediums/ble_v2/BUILD
index cd9321e8..17241f9e 100644
--- a/connections/implementation/mediums/ble_v2/BUILD
+++ b/connections/implementation/mediums/ble_v2/BUILD
@@ -50,6 +50,7 @@ cc_library(
         "//internal/platform:uuid",
         "//proto/mediums:ble_frames_cc_proto",
         "@aappleby_smhasher//:libmurmur3",
+        "@com_google_absl//absl/base:core_headers",
         "@com_google_absl//absl/container:flat_hash_map",
         "@com_google_absl//absl/container:flat_hash_set",
         "@com_google_absl//absl/numeric:int128",
diff --git a/connections/implementation/mediums/ble_v2/discovered_peripheral_tracker.cc b/connections/implementation/mediums/ble_v2/discovered_peripheral_tracker.cc
index 3153ca1f..806cf3dc 100644
--- a/connections/implementation/mediums/ble_v2/discovered_peripheral_tracker.cc
+++ b/connections/implementation/mediums/ble_v2/discovered_peripheral_tracker.cc
@@ -30,6 +30,7 @@
 #include "connections/implementation/mediums/ble_v2/bloom_filter.h"
 #include "internal/flags/nearby_flags.h"
 #include "internal/platform/ble_v2.h"
+#include "internal/platform/byte_array.h"
 #include "internal/platform/logging.h"
 #include "internal/platform/multi_thread_executor.h"
 #include "internal/platform/mutex_lock.h"
@@ -521,13 +522,35 @@ void DiscoveredPeripheralTracker::HandleAdvertisementHeader(
                            << absl::BytesToHexString(
                                   ByteArray(advertisement_header).data())
                            << " in thread";
+      ByteArray advertisement_data{advertisement_header};
+      if (fetching_advertisements_.contains(advertisement_data)) {
+        NEARBY_LOGS(VERBOSE) << ": Ignore the advertisement header due to it "
+                              "is already in fetcing.";
+        return;
+      }
+
+      fetching_advertisements_.insert(advertisement_data);
+
       if (executor_ == nullptr) {
         // The situation happens when flag value changed
         executor_ = std::make_unique<MultiThreadExecutor>(kGattThreadCount);
       }
       executor_->Execute([this, peripheral, advertisement_header,
                           advertisement_fetcher =
-                              std::move(advertisement_fetcher)]() {
+                              std::move(advertisement_fetcher),
+                          advertisement_data =
+                              std::move(advertisement_data)]() {
+        {
+          MutexLock lock(&mutex_);
+          if (!IsInterestingAdvertisementHeader(advertisement_header)) {
+            NEARBY_LOGS(INFO)
+                << ": Ignore to read raw advertisement from server due to it "
+                   "is not interesting header now.";
+            fetching_advertisements_.erase(advertisement_data);
+            return;
+          }
+        }
+
         std::vector<const ByteArray*> gatt_advertisement_bytes_list =
             FetchRawAdvertisementsInThread(peripheral, advertisement_header,
                                            std::move(advertisement_fetcher));
@@ -537,6 +560,7 @@ void DiscoveredPeripheralTracker::HandleAdvertisementHeader(
                                       gatt_advertisement_bytes_list,
                                       /*service_uuid=*/{});
           UpdateCommonStateForFoundBleAdvertisement(advertisement_header);
+          fetching_advertisements_.erase(advertisement_data);
           NEARBY_LOGS(VERBOSE)
               << ": Completed to handle GATT advertisement "
               << absl::BytesToHexString(ByteArray(advertisement_header).data())
diff --git a/connections/implementation/mediums/ble_v2/discovered_peripheral_tracker.h b/connections/implementation/mediums/ble_v2/discovered_peripheral_tracker.h
index 423514cb..fcd59951 100644
--- a/connections/implementation/mediums/ble_v2/discovered_peripheral_tracker.h
+++ b/connections/implementation/mediums/ble_v2/discovered_peripheral_tracker.h
@@ -20,6 +20,9 @@
 #include <string>
 #include <vector>
 
+#include "absl/base/thread_annotations.h"
+#include "absl/container/flat_hash_map.h"
+#include "absl/container/flat_hash_set.h"
 #include "connections/implementation/mediums//lost_entity_tracker.h"
 #include "connections/implementation/mediums/ble_v2/advertisement_read_result.h"
 #include "connections/implementation/mediums/ble_v2/ble_advertisement.h"
@@ -289,6 +292,10 @@ class DiscoveredPeripheralTracker {
   absl::flat_hash_map<BleAdvertisement, GattAdvertisementInfo>
       gatt_advertisement_infos_ ABSL_GUARDED_BY(mutex_);
 
+  // Tracks the advertisements in GATT fetching.
+  absl::flat_hash_set<ByteArray> fetching_advertisements_
+      ABSL_GUARDED_BY(mutex_);
+
   std::unique_ptr<MultiThreadExecutor> executor_ ABSL_GUARDED_BY(mutex_) =
       nullptr;
 };