1 files changed, 104 insertions, 0 deletions
diff --git a/chromium/third_party/nearby/src/connections/implementation/mediums/ble_v2/advertisement_read_result.h b/chromium/third_party/nearby/src/connections/implementation/mediums/ble_v2/advertisement_read_result.h
new file mode 100644
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+++ b/chromium/third_party/nearby/src/connections/implementation/mediums/ble_v2/advertisement_read_result.h
@@ -0,0 +1,104 @@
+// Copyright 2020 Google LLC
+//
+// 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
+//
+//     https://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.
+
+#ifndef CORE_INTERNAL_MEDIUMS_BLE_V2_ADVERTISEMENT_READ_RESULT_H_
+#define CORE_INTERNAL_MEDIUMS_BLE_V2_ADVERTISEMENT_READ_RESULT_H_
+
+#include <cstdint>
+#include <vector>
+
+#include "absl/container/flat_hash_map.h"
+#include "absl/container/flat_hash_set.h"
+#include "absl/time/clock.h"
+#include "internal/platform/byte_array.h"
+#include "internal/platform/mutex.h"
+#include "internal/platform/system_clock.h"
+
+namespace location {
+namespace nearby {
+namespace connections {
+namespace mediums {
+
+// Representation of a GATT advertisement read result. This object helps us
+// determine whether or not we need to retry GATT reads.
+class AdvertisementReadResult {
+ public:
+  // We need a long enough duration such that we always trigger a read
+  // retry AND we always connect to it without delay. The former case
+  // helps us initialize an AdvertisementReadResult so that we
+  // unconditionally try reading on the first sighting. And the latter
+  // case helps us connect immediately when we initialize a dummy read
+  // result for fast advertisements (which don't use the GATT server).
+
+  struct Config {
+    // How much to multiply the backoff duration by with every failure to read
+    // from the advertisement GATT server. This should never be below 1!
+    float backoff_multiplier;
+    // The initial backoff duration when we fail to read from an advertisement
+    // GATT server.
+    absl::Duration base_backoff_duration;
+    // The maximum backoff duration allowed between advertisement GATT server
+    // reads.
+    absl::Duration max_backoff_duration;
+  };
+
+  static const Config kDefaultConfig;
+  explicit AdvertisementReadResult(const Config& config = kDefaultConfig)
+      : config_(config) {}
+  ~AdvertisementReadResult() = default;
+
+  enum class RetryStatus {
+    kUnknown = 0,
+    kRetry = 1,
+    kPreviouslySucceeded = 2,
+    kTooSoon = 3,
+  };
+
+  void AddAdvertisement(std::int32_t slot, const ByteArray& advertisement)
+      ABSL_LOCKS_EXCLUDED(mutex_);
+  bool HasAdvertisement(std::int32_t slot) const ABSL_LOCKS_EXCLUDED(mutex_);
+  std::vector<const ByteArray*> GetAdvertisements() const
+      ABSL_LOCKS_EXCLUDED(mutex_);
+  RetryStatus EvaluateRetryStatus() const ABSL_LOCKS_EXCLUDED(mutex_);
+  void RecordLastReadStatus(bool is_success) ABSL_LOCKS_EXCLUDED(mutex_);
+  absl::Duration GetDurationSinceRead() const ABSL_LOCKS_EXCLUDED(mutex_);
+
+ private:
+  enum class Status {
+    kUnknown = 0,
+    kSuccess = 1,
+    kFailure = 2,
+  };
+
+  absl::Duration GetDurationSinceReadLocked() const
+      ABSL_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+
+  mutable Mutex mutex_;
+
+  // Maps slot numbers to the GATT advertisement found in that slot.
+  absl::flat_hash_map<std::int32_t, ByteArray> advertisements_
+      ABSL_GUARDED_BY(mutex_);
+
+  Config config_;
+  absl::Duration backoff_duration_ ABSL_GUARDED_BY(mutex_);
+  absl::Time last_read_timestamp_ ABSL_GUARDED_BY(mutex_);
+  Status status_ ABSL_GUARDED_BY(mutex_) = Status::kUnknown;
+};
+
+}  // namespace mediums
+}  // namespace connections
+}  // namespace nearby
+}  // namespace location
+
+#endif  // CORE_INTERNAL_MEDIUMS_BLE_V2_ADVERTISEMENT_READ_RESULT_H_