[Chromecast] Make FakeStreamSocket more realistic

 * Don't allow pending reads to complete within a write call.
 * Signal EOS when the other end of the socket disconnects.

Merge-With: eureka-internal/381432
Change-Id: Ia091361fc0c72da52c76c9fcf98b7c24a04d9f13
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2129996Reviewed-by: Yuchen Liu <yucliu@chromium.org>
Commit-Queue: Kenneth MacKay <kmackay@chromium.org>
Cr-Commit-Position: refs/heads/master@{#755031}

chromecast/net/fake_stream_socket.cc

@@ -8,8 +8,12 @@
 #include <cstring>
 #include <vector>
 
+#include "base/bind.h"
 #include "base/callback_helpers.h"
+#include "base/location.h"
 #include "base/logging.h"
+#include "base/memory/weak_ptr.h"
+#include "base/threading/sequenced_task_runner_handle.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
 #include "net/socket/next_proto.h"
@@ -31,8 +35,11 @@ class SocketBuffer {
   int Read(char* data, size_t len, net::CompletionOnceCallback callback) {
     DCHECK(data);
     DCHECK_GT(len, 0u);
-    DCHECK(!callback.is_null());
+    DCHECK(callback);
     if (data_.empty()) {
+      if (eos_) {
+        return 0;
+      }
       pending_read_data_ = data;
       pending_read_len_ = len;
       pending_read_callback_ = std::move(callback);
@@ -51,7 +58,15 @@ class SocketBuffer {
       int result = ReadInternal(pending_read_data_, pending_read_len_);
       pending_read_data_ = nullptr;
       pending_read_len_ = 0;
-      std::move(pending_read_callback_).Run(result);
+      PostReadCallback(std::move(pending_read_callback_), result);
+    }
+  }
+
+  // Called when the remote end of the fake connection disconnects.
+  void ReceiveEOS() {
+    eos_ = true;
+    if (pending_read_callback_ && data_.empty()) {
+      PostReadCallback(std::move(pending_read_callback_), 0);
     }
   }
 
@@ -65,10 +80,25 @@ class SocketBuffer {
     return len;
   }
 
+  void PostReadCallback(net::CompletionOnceCallback callback, int result) {
+    base::SequencedTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE, base::BindOnce(&SocketBuffer::CallReadCallback,
+                                  weak_factory_.GetWeakPtr(),
+                                  std::move(callback), result));
+  }
+
+  // Need a member function to asynchronously call the read callback, so we
+  // can use weak ptr.
+  void CallReadCallback(net::CompletionOnceCallback callback, int result) {
+    std::move(callback).Run(result);
+  }
+
   std::vector<char> data_;
   char* pending_read_data_;
   size_t pending_read_len_;
   net::CompletionOnceCallback pending_read_callback_;
+  bool eos_ = false;
+  base::WeakPtrFactory<SocketBuffer> weak_factory_{this};
 
   DISALLOW_COPY_AND_ASSIGN(SocketBuffer);
 };
@@ -82,7 +112,7 @@ FakeStreamSocket::FakeStreamSocket(const net::IPEndPoint& local_address)
 
 FakeStreamSocket::~FakeStreamSocket() {
   if (peer_) {
-    peer_->peer_ = nullptr;
+    peer_->RemoteDisconnected();
   }
 }
 
@@ -91,6 +121,11 @@ void FakeStreamSocket::SetPeer(FakeStreamSocket* peer) {
   peer_ = peer;
 }
 
+void FakeStreamSocket::RemoteDisconnected() {
+  peer_ = nullptr;
+  buffer_->ReceiveEOS();
+}
+
 void FakeStreamSocket::SetBadSenderMode(bool bad_sender) {
   bad_sender_mode_ = bad_sender;
 }

chromecast/net/fake_stream_socket.h

@@ -61,6 +61,8 @@ class FakeStreamSocket : public net::StreamSocket {
   void ApplySocketTag(const net::SocketTag& tag) override;
 
  private:
+  void RemoteDisconnected();
+
   const net::IPEndPoint local_address_;
   const std::unique_ptr<SocketBuffer> buffer_;
   FakeStreamSocket* peer_;

chromecast/net/fake_stream_socket_unittest.cc

@@ -10,6 +10,7 @@
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
+#include "base/test/task_environment.h"
 #include "chromecast/net/fake_stream_socket.h"
 #include "net/base/io_buffer.h"
 #include "net/base/ip_endpoint.h"
@@ -45,6 +46,7 @@ class FakeStreamSocketTest : public ::testing::Test {
         socket_2_(endpoint_2_) {}
   ~FakeStreamSocketTest() override {}
 
+  base::test::TaskEnvironment task_environment_;
   net::IPEndPoint endpoint_1_;
   FakeStreamSocket socket_1_;
   net::IPEndPoint endpoint_2_;
@@ -65,6 +67,7 @@ TEST_F(FakeStreamSocketTest, GetPeerAddressWithoutPeer) {
 
 TEST_F(FakeStreamSocketTest, GetPeerAddressWithPeer) {
   socket_1_.SetPeer(&socket_2_);
+  socket_2_.SetPeer(&socket_1_);
   net::IPEndPoint peer_address;
   ASSERT_EQ(net::OK, socket_1_.GetPeerAddress(&peer_address));
   EXPECT_EQ(endpoint_2_, peer_address);