Convert mdns Builder classes to use PacketBufferHandle (#4094)

* Convert mdns Builder classes to use PacketBufferHandle #### Problem Code should use `PacketBufferHandle` rather than `PacketBuffer` directly. #### Summary of Changes Convert mdns::Minimal::QueryBuilder and mdns::Minimal::ResponseBuilder to take and hold PacketBufferHandle. Part of issue #2707 - Figure out a way to express PacketBuffer ownership in the type system * Review: make QueryBuilder take const& * WIP * Revise to match ResponseBuilder in #4102 * Restyled by clang-format * remove PacketReporter.cpp change Co-authored-by: Restyled.io <[email protected]>
project-chip · Jan 8, 2021 · f77bebf · f77bebf
1 parent f9748f3
commit f77bebf
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Showing 2 changed files with 22 additions and 10 deletions.
diff --git a/examples/minimal-mdns/client.cpp b/examples/minimal-mdns/client.cpp
@@ -261,7 +261,7 @@ void BroadcastPacket(mdns::Minimal::ServerBase * server)
     QuerySplitter query;
     query.Split(gOptions.query);
 
-    mdns::Minimal::QueryBuilder builder(buffer.Get_ForNow());
+    mdns::Minimal::QueryBuilder builder(std::move(buffer));
 
     builder.Header().SetMessageId(kTestMessageId);
     builder.AddQuery(query
@@ -277,7 +277,7 @@ void BroadcastPacket(mdns::Minimal::ServerBase * server)
         return;
     }
 
-    if (server->BroadcastSend(std::move(buffer), gOptions.querySendPort) != CHIP_NO_ERROR)
+    if (server->BroadcastSend(builder.ReleasePacket, gOptions.querySendPort) != CHIP_NO_ERROR)
     {
         printf("Error sending\n");
         return;

diff --git a/src/lib/mdns/minimal/QueryBuilder.h b/src/lib/mdns/minimal/QueryBuilder.h
@@ -28,27 +28,39 @@ namespace Minimal {
 class QueryBuilder
 {
 public:
-    QueryBuilder(chip::System::PacketBuffer * packet) : mPacket(packet), mHeader(mPacket->Start())
-    {
+    QueryBuilder() : mHeader(nullptr) {}
+    QueryBuilder(chip::System::PacketBufferHandle && packet) : mHeader(nullptr) { Reset(std::move(packet)); }
 
+    QueryBuilder & Reset(chip::System::PacketBufferHandle && packet)
+    {
+        mPacket = std::move(packet);
         if (mPacket->AvailableDataLength() >= HeaderRef::kSizeBytes)
         {
             mPacket->SetDataLength(HeaderRef::kSizeBytes);
             mHeader.Clear();
         }
         else
         {
-            mQueryBuidOk = false;
+            mQueryBuildOk = false;
         }
 
         mHeader.SetFlags(mHeader.GetFlags().SetQuery());
+        return *this;
+    }
+
+    CHECK_RETURN_VALUE
+    chip::System::PacketBufferHandle && ReleasePacket()
+    {
+        mHeader       = HeaderRef(nullptr);
+        mQueryBuildOk = false;
+        return std::move(mPacket);
     }
 
     HeaderRef & Header() { return mHeader; }
 
     QueryBuilder & AddQuery(const Query & query)
     {
-        if (!mQueryBuidOk)
+        if (!mQueryBuildOk)
         {
             return *this;
         }
@@ -57,7 +69,7 @@ class QueryBuilder
 
         if (!query.Append(mHeader, out))
         {
-            mQueryBuidOk = false;
+            mQueryBuildOk = false;
         }
         else
         {
@@ -66,12 +78,12 @@ class QueryBuilder
         return *this;
     }
 
-    bool Ok() const { return mQueryBuidOk; }
+    bool Ok() const { return mQueryBuildOk; }
 
 private:
-    chip::System::PacketBuffer * mPacket;
+    chip::System::PacketBufferHandle mPacket;
     HeaderRef mHeader;
-    bool mQueryBuidOk = true;
+    bool mQueryBuildOk = true;
 };
 
 } // namespace Minimal