Make PacketReader/PacketWriter interfaces async-only.

blimp/net/stream_packet_reader.cc

Index: blimp/net/stream_packet_reader.cc
diff --git a/blimp/net/stream_packet_reader.cc b/blimp/net/stream_packet_reader.cc
index 8da613020feaf66b7a840a186121379cbe6647cc..e50074865076abb84b88230070557093e2839f5e 100644
--- a/blimp/net/stream_packet_reader.cc
+++ b/blimp/net/stream_packet_reader.cc
@@ -9,6 +9,7 @@
 #include "base/callback_helpers.h"
 #include "base/logging.h"
 #include "base/memory/weak_ptr.h"
+#include "base/message_loop/message_loop.h"
 #include "base/sys_byteorder.h"
 #include "blimp/net/common.h"
 #include "net/base/io_buffer.h"
@@ -42,7 +43,7 @@ StreamPacketReader::StreamPacketReader(net::StreamSocket* socket)
 
 StreamPacketReader::~StreamPacketReader() {}
 
-int StreamPacketReader::ReadPacket(
+void StreamPacketReader::ReadPacket(
     const scoped_refptr<net::GrowableIOBuffer>& buf,
     const net::CompletionCallback& callback) {
   DCHECK_EQ(ReadState::IDLE, read_state_);
@@ -54,17 +55,17 @@ int StreamPacketReader::ReadPacket(
   read_state_ = ReadState::HEADER;
 
   int result = DoReadLoop(net::OK);
-  if (result == net::ERR_IO_PENDING) {
-    // Store the completion callback to invoke when read completes
-    // asynchronously.
-    callback_ = callback;
-  } else {
+  if (result != net::ERR_IO_PENDING) {
     // Release the payload buffer, since the read operation has completed
     // synchronously.
     payload_buffer_ = nullptr;
-  }
 
-  return result;
+    // Adapt synchronous completion to an asynchronous style.
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::Bind(callback, result));

[Wez, 2015/12/01 22:34:45]

What happens if |this| is deleted by the caller before this task is run?

[Kevin M, 2015/12/02 02:02:37]

Seems fine to me - |callback| is supplied by the caller and doesn't refer to
anything in StreamPacketReader?

In practice, the caller is BlimpMessagePump, which will be destroyed before
StreamPacketReader and uses a CancelableCallback for its read cb.

+  } else {
+    callback_ = callback;
+  }
 }
 
 int StreamPacketReader::DoReadLoop(int result) {
@@ -134,7 +135,7 @@ int StreamPacketReader::DoReadPayload(int result) {
 
   // Finished reading the payload.
   read_state_ = ReadState::IDLE;
-  return payload_size_;
+  return net::OK;
 }
 
 void StreamPacketReader::OnReadComplete(int result) {