[Nearby] Implement missing cancel functionality

Follow up bug for unit-tests: https://crbug.com/1148598

Fixed: 1145752
Change-Id: Ie9ee724f03498264b75b9f2ff31e5f4517ceb9d3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2534293
Commit-Queue: James Vecore <vecore@google.com>
Reviewed-by: Josh Nohle <nohle@chromium.org>
Cr-Commit-Position: refs/heads/master@{#827174}

chrome/browser/nearby_sharing/constants.h

@@ -28,6 +28,12 @@ constexpr base::TimeDelta kOutgoingDisconnectionDelay =
 constexpr base::TimeDelta kIncomingRejectionDelay =
     base::TimeDelta::FromSeconds(2);
 
+// The delay before the receiver will disconnect from the sender after canceling
+// an in progress share. The sender is expected to disconnect immediately after
+// reading the rejection frame.
+constexpr base::TimeDelta kIncomingCancelDelay =
+    base::TimeDelta::FromSeconds(5);
+
 // Timeout for reading a frame from remote device.
 constexpr base::TimeDelta kReadFramesTimeout = base::TimeDelta::FromSeconds(15);
 

chrome/browser/nearby_sharing/nearby_sharing_service_impl.cc

@@ -748,6 +748,43 @@ void NearbySharingServiceImpl::Reject(
 void NearbySharingServiceImpl::Cancel(
     const ShareTarget& share_target,
     StatusCodesCallback status_codes_callback) {
+  ShareTargetInfo* info = GetShareTargetInfo(share_target);
+
+  if (!info || !info->connection() || !info->endpoint_id()) {
+    NS_LOG(ERROR) << __func__
+                  << ": Cancel invoked for unknown share target, returning "
+                     "kOutOfOrderApiCall";
+    // Make sure to clean up files just in case.
+    OnPayloadsFailed(share_target);
+    std::move(status_codes_callback).Run(StatusCodes::kOutOfOrderApiCall);
+    return;
+  }
+
+  base::SequencedTaskRunnerHandle::Get()->PostDelayedTask(
+      FROM_HERE,
+      base::BindOnce(&NearbySharingServiceImpl::CloseConnection,
+                     weak_ptr_factory_.GetWeakPtr(), share_target),
+      kIncomingCancelDelay);
+
+  info->connection()->SetDisconnectionListener(
+      base::BindOnce(&NearbySharingServiceImpl::UnregisterShareTarget,
+                     weak_ptr_factory_.GetWeakPtr(), share_target));
+
+  NS_LOG(INFO) << __func__
+               << ": User canceled transfer, write cancel frame and generating "
+                  "local status update.";
+
+  WriteCancel(*info->connection());
+
+  if (info->transfer_update_callback()) {
+    info->transfer_update_callback()->OnTransferUpdate(
+        share_target, TransferMetadataBuilder()
+                          .set_status(TransferMetadata::Status::kCancelled)
+                          .build());
+  }
+
+  // Make sure to clean up files if necessary
+  OnPayloadsFailed(share_target);
   std::move(status_codes_callback).Run(StatusCodes::kOk);
 }
 
@@ -2194,6 +2231,18 @@ void NearbySharingServiceImpl::WriteResponse(
   connection.Write(std::move(data));
 }
 
+void NearbySharingServiceImpl::WriteCancel(NearbyConnection& connection) {
+  sharing::nearby::Frame frame;
+  frame.set_version(sharing::nearby::Frame::V1);
+  sharing::nearby::V1Frame* v1_frame = frame.mutable_v1();
+  v1_frame->set_type(sharing::nearby::V1Frame::CANCEL);
+
+  std::vector<uint8_t> data(frame.ByteSize());
+  frame.SerializeToArray(data.data(), frame.ByteSize());
+
+  connection.Write(std::move(data));
+}
+
 void NearbySharingServiceImpl::Fail(const ShareTarget& share_target,
                                     TransferMetadata::Status status) {
   ShareTargetInfo* info = GetShareTargetInfo(share_target);

chrome/browser/nearby_sharing/nearby_sharing_service_impl.h

@@ -228,6 +228,7 @@ class NearbySharingServiceImpl
   void WriteResponse(
       NearbyConnection& connection,
       sharing::nearby::ConnectionResponseFrame::Status reponse_status);
+  void WriteCancel(NearbyConnection& connection);
   void Fail(const ShareTarget& share_target, TransferMetadata::Status status);
   void OnIncomingAdvertisementDecoded(
       const std::string& endpoint_id,