Replace StreamListenSocket with StreamSocket in HttpServer.

net/server/http_connection.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/server/http_connection.h"
 
+#include <queue>
+
+#include "base/bind.h"
+#include "base/location.h"
+#include "base/message_loop/message_loop_proxy.h"
+#include "net/base/net_errors.h"
 #include "net/server/http_server.h"
 #include "net/server/http_server_response_info.h"
 #include "net/server/web_socket.h"
-#include "net/socket/stream_listen_socket.h"
+#include "net/socket/stream_socket.h"
 
 namespace net {
 
-int HttpConnection::last_id_ = 0;
+namespace {
+
+const size_t kInitialReadBufSize = 1024;
+const size_t kMinimumReadBufSize = 128;
+const int kCapacityIncreaseFactor = 2;
+
+const size_t kPendingDataLimit = 1 * 1024 * 1024;  // 1 Mbytes.
+
+}  // namespace
+
+HttpConnection::ReadIOBuffer::ReadIOBuffer()
+    : base_(new GrowableIOBuffer()) {
+  SetCapacity(kInitialReadBufSize);
+}
+
+HttpConnection::ReadIOBuffer::~ReadIOBuffer() {
+  data_ = NULL;  // base_ owns data_.
+}
+
+IOBuffer* HttpConnection::ReadIOBuffer::GetUnusedIOBuffer() const {
+  return base_.get();
+}
+
+size_t HttpConnection::ReadIOBuffer::GetUnusedCapacity() const {
+  return static_cast<size_t>(base_->RemainingCapacity());
+}
+
+size_t HttpConnection::ReadIOBuffer::GetCapacity() const {
+  return static_cast<size_t>(base_->capacity());
+}
+
+void HttpConnection::ReadIOBuffer::SetCapacity(size_t capacity) {
+  base_->SetCapacity(static_cast<int>(capacity));
+  data_ = base_->StartOfBuffer();
+}
+
+size_t HttpConnection::ReadIOBuffer::GetUnconsumedSize() const {
+  DCHECK_GE(base_->data(), data_);
+  return static_cast<size_t>(base_->data() - data_);
+}
+
+void HttpConnection::ReadIOBuffer::DidRead(size_t bytes) {
+  DCHECK_LE(bytes, GetUnusedCapacity());
+  base_->set_offset(base_->offset() + bytes);
+}
+
+void HttpConnection::ReadIOBuffer::DidConsume(size_t bytes) {
+  DCHECK_LE(bytes, GetUnconsumedSize());
+  if (bytes < GetUnconsumedSize()) {
+    data_ += bytes;
+    return;
+  }
+  // No need to keep consumed data because no data will be moved.
+  // If capacity is too big, reduce it.
+  if (base_->capacity() > static_cast<int>(kMinimumReadBufSize)
+      && base_->capacity() > base_->offset() * kCapacityIncreaseFactor) {
+    SetCapacity(base_->capacity() / kCapacityIncreaseFactor);
+  }
+  base_->set_offset(0);
+}
+
+// IOBuffer of pending data which has a queue of pending data. Each pending data
+// is stored in std::string. data() is the data of first std::string stored.
+class HttpConnection::PendingWriteIOBuffer : public IOBuffer {
+ public:
+  PendingWriteIOBuffer();
+
+  // Whether or not pending data exists.
+  bool IsEmpty() const;
+
+  // Appends new pending data. Changes data() if this is the first pending data.
+  void Append(const std::string& data);
+  // Consumes data and changes data() accordingly.
+  void DidConsume(size_t size);
+
+  // Gets size of data to write this time. It is NOT total data size.
+  size_t GetSizeToWrite() const;
+
+  size_t total_size() const { return total_size_; }
+
+ private:
+  virtual ~PendingWriteIOBuffer();
+
+  std::queue<std::string> pending_data_;
+  size_t total_size_;
+
+  DISALLOW_COPY_AND_ASSIGN(PendingWriteIOBuffer);
+};
+
+HttpConnection::PendingWriteIOBuffer::PendingWriteIOBuffer()
+    : total_size_(0) {
+}
+
+HttpConnection::PendingWriteIOBuffer::~PendingWriteIOBuffer() {
+}
+
+bool HttpConnection::PendingWriteIOBuffer::IsEmpty() const {
+  return pending_data_.empty();
+}
+
+void HttpConnection::PendingWriteIOBuffer::Append(const std::string& data) {
+  if (data.empty()) {
+    return;
+  }
+
+  pending_data_.push(data);

[mmenke, 2014/05/23 19:20:58]

Can't we just take IOBuffers instead, to avoid this copy?

[byungchul, 2014/05/28 01:19:35]

To construct IOBuffer from std::string in any point before here, it must be
StringIOBuffer() which also uses std::string's ctor internally. So, same
behavior unless HttpServer::Send() signature changes.
And, no copy if std::string implements copy-on-write.
And, t

[Ryan Sleevi, 2014/05/28 01:36:26]

Copy-on-write is forbidden behaviour in C++11, and was never reliable behaviour
before.

I think the goal (of IOBuffer) is that IOBuffer is viral all the layers up. That
is, changing multiple layers to take either a net::IOBuffer or (if a copy is
absolutely necessary), base::StringPiece. Preferably though, IOBuffer through
and through.

[byungchul, 2014/05/30 00:19:02]

Now, HttpServer uses this buffer directly. Building IOBuffer() just make an
overhead.

+  total_size_ += data.size();
+
+  // If new data is the first pending data, updates data_.
+  if (pending_data_.size() == 1) {
+    data_ = const_cast<char*>(pending_data_.front().data());
+  }
+}
+
+void HttpConnection::PendingWriteIOBuffer::DidConsume(size_t size) {
+  DCHECK_LE(size, total_size_);
+  DCHECK_LE(size, GetSizeToWrite());
+  if (size == 0) {
+    return;
+  }
+
+  if (size < GetSizeToWrite()) {
+    data_ += size;
+  } else {  // size == GetSizeToWrite(). Updates data_ to next pending data.
+    pending_data_.pop();
+    data_ = IsEmpty() ? NULL : const_cast<char*>(pending_data_.front().data());
+  }
+  total_size_ -= size;
+}
+
+size_t HttpConnection::PendingWriteIOBuffer::GetSizeToWrite() const {
+  if (IsEmpty()) {
+    DCHECK_EQ(total_size_, 0U);
+    return 0;
+  }
+  DCHECK_GE(data_, pending_data_.front().data());
+  size_t consumed = static_cast<size_t>(data_ - pending_data_.front().data());
+  DCHECK_GT(pending_data_.front().size(), consumed);

[mmenke, 2014/05/23 19:20:58]

This class may be may effort than it's worth, as-is, it works it fairly
non-obvious ways.  One option would just be to have the HttpConnection directly
manage the item at the top of the queue, and have this class manage everything
else.

[mmenke, 2014/05/23 19:20:58]

Actually...Why don't we do something simpler, like just not supporting
pipelining, and only having one send call until the previous one completes?

[byungchul, 2014/05/28 01:19:35]

Any one needs to store date to write anyway. My implementation is here. Do you
mean http server, or http connection?

[Ryan Sleevi, 2014/05/28 01:36:26]

Normally, in net/ code, we leave buffering up to the highest layer possible, so
that it can adapt the most reasonable backoff metrics.

[byungchul, 2014/05/28 05:01:33]

While keeping current HttpServer apis, I will try to do:
1) move read/write function to HttpServer and handle callbacks directly which
will remove necessity of delegate and/so weak ptr.
2) HttpConnection is still useful as a container of information of each http
connection including id, underlying socket, and pending buffer for read and
write.

Make sense?

[byungchul, 2014/05/30 00:19:02]

Done.

+  return pending_data_.front().size() - consumed;
+}
+
+HttpConnection::HttpConnection(int id,
+                               scoped_ptr<StreamSocket> socket,
+                               Delegate* delegate)
+    : id_(id),
+      socket_(socket.Pass()),
+      delegate_(delegate),
+      read_buf_(new ReadIOBuffer()),
+      pending_write_buf_(new PendingWriteIOBuffer()) {
+  DoReadLoop(OK);
+}
+
+HttpConnection::~HttpConnection() {
+}
+
+void HttpConnection::DoReadLoop(int rv) {

[mmenke, 2014/05/23 19:20:58]

Taking in an "rv" that's always OK seems a little odd.  Should either get rid of
the parameter, or restructure the loop so it takes the rv of the last read as
input (The latter is a little complicated, because on the first call, it will be
0, which is the same value we get on EOF).

[byungchul, 2014/05/30 00:19:02]

Done and moved to HttpServer.

+  while (rv == OK) {
+    if (read_buf_->GetUnusedCapacity() == 0) {
+      if (read_buf_->GetCapacity() > kPendingDataLimit) {
+        LOG(ERROR) << "Too large read data is pending: capacity="
+                   << read_buf_->GetCapacity()
+                   << ", consumed="
+                   << read_buf_->GetCapacity() - read_buf_->GetUnconsumedSize();
+        Close();
+        return;
+      }
+      read_buf_->SetCapacity(read_buf_->GetCapacity() * kMinimumReadBufSize);
+    }
+    rv = socket_->Read(read_buf_->GetUnusedIOBuffer(),
+                       read_buf_->GetUnusedCapacity(),
+                       base::Bind(&HttpConnection::OnReadCompleted,
+                                  AsWeakPtr()));

[mmenke, 2014/05/23 19:20:58]

We don't need weak pointers here - we own the socket, and it won't call us after
we delete it.

[byungchul, 2014/05/30 00:19:02]

Replaced with connection id in http server.

+    if (rv == ERR_IO_PENDING) {
+      break;
+    }
+    rv = DidRead(rv);
+  }
+}
+
+void HttpConnection::OnReadCompleted(int rv) {
+  if (DidRead(rv) == OK) {
+    DoReadLoop(OK);
+  }
+}
+
+int HttpConnection::DidRead(int rv) {
+  if (rv <= 0) {
+    Close();
+    return rv == 0 ? ERR_CONNECTION_CLOSED : rv;
+  }
+
+  read_buf_->DidRead(static_cast<size_t>(rv));
+  delegate_->DidRead(this);
+  return OK;
+}
 
 void HttpConnection::Send(const std::string& data) {
-  if (!socket_.get())
-    return;
-  socket_->Send(data);
+  if (pending_write_buf_->total_size() + data.size() > kPendingDataLimit) {

[pfeldman, 2014/05/26 09:21:31]

Before we go further, could you elaborate on this limitation though? DevTools is
sending 100Mb payloads using this method.

[mmenke, 2014/05/27 14:32:08]

It's buffering 100 MB payloads in RAM?  That just seems a bad idea.

[byungchul, 2014/05/30 00:19:02]

Increased websocket buffer to 100Mb in cast of devtools websocket.

+    LOG(ERROR) << "Too large write data is pending: size="
+               << pending_write_buf_->total_size() + data.size();
+    Close();
+    return;
+  }
+  bool writing_in_progress = !pending_write_buf_->IsEmpty();
+  pending_write_buf_->Append(data);
+  if (!writing_in_progress) {
+    DoWriteLoop(OK);
+  }
 }
 
 void HttpConnection::Send(const char* bytes, int len) {
-  if (!socket_.get())
-    return;
-  socket_->Send(bytes, len);
+  Send(std::string(bytes, len));

[mmenke, 2014/05/23 19:20:58]

This copy really shouldn't be needed.

[byungchul, 2014/05/30 00:19:02]

This is used only by net/server/web_socket.cc. One for header(16 bytes), one for
framing (2 bytes). Remove this function, and copy happens in websocket.cc (or
caller) which can optimize if necessary while keeping http server api simple.

 }
 
 void HttpConnection::Send(const HttpServerResponseInfo& response) {
   Send(response.Serialize());
 }
 
-HttpConnection::HttpConnection(HttpServer* server,
-                               scoped_ptr<StreamListenSocket> sock)
-    : server_(server),
-      socket_(sock.Pass()) {
-  id_ = last_id_++;
-}
-
-HttpConnection::~HttpConnection() {
-  server_->delegate_->OnClose(id_);
-}
-
-void HttpConnection::Shift(int num_bytes) {
-  recv_data_ = recv_data_.substr(num_bytes);
+void HttpConnection::DoWriteLoop(int rv) {

[mmenke, 2014/05/23 19:20:58]

Again, rv is always "OK", so doesn't seem like it should be needed.

[byungchul, 2014/05/30 00:19:02]

Done.

+  while (rv == OK && pending_write_buf_->GetSizeToWrite() > 0) {
+    rv = socket_->Write(pending_write_buf_.get(),
+                        pending_write_buf_->GetSizeToWrite(),
+                        base::Bind(&HttpConnection::OnWriteCompleted,
+                                   AsWeakPtr()));

[mmenke, 2014/05/23 19:20:58]

WeakPtr not needed.

[byungchul, 2014/05/30 00:19:02]

Done.

+    if (rv == ERR_IO_PENDING || rv == OK) {
+      break;
+    }
+    rv = DidWrite(rv);
+  }
+}
+
+void HttpConnection::OnWriteCompleted(int rv) {
+  if (DidWrite(rv) == OK) {
+    DoWriteLoop(OK);
+  }
+}
+
+int HttpConnection::DidWrite(int rv) {
+  if (rv < 0) {
+    Close();
+    return rv;
+  }
+
+  pending_write_buf_->DidConsume(rv);
+  return OK;
+}
+
+void HttpConnection::Close() {

[mmenke, 2014/05/23 19:20:58]

This function can end up being called twice:  Once on read error, once on write
error, which could result in calling into the delegate twice, which seems like a
potential problem.

[byungchul, 2014/05/28 01:19:35]

That's why I use a weak ptr.

[Ryan Sleevi, 2014/05/28 01:36:26]

I don't really think that's an ideal solution.

Note that in net, we use the (spiritual equivalent, sometimes literal) of
base::ResetAndReturn(cb_).Run(value) as the terminal call in the callstack, so
that everything is unwound in the socket. Even if cb_ deletes the socket, it's
safe, because it was stack allocated in the processing.

eg: See
https://code.google.com/p/chromium/codesearch#chromium/src/net/socket/tcp_soc...
or
https://code.google.com/p/chromium/codesearch#chromium/src/net/socket/ssl_cli...

[byungchul, 2014/05/30 00:19:02]

HttpServer handles it and/so never calls Close() twice because it removes it
from id_connection_map.

+  // DidClose() may delete this object. Call it in next run loop to make sure
+  // any DidRead()/DidWrite() callbacks in the stack return.
+  base::MessageLoopProxy::current()->PostTask(
+      FROM_HERE,
+      base::Bind(&HttpConnection::CloseInNextRunLoop, AsWeakPtr()));

[mmenke, 2014/05/23 19:20:58]

So we always call back Delegate::DidClose asynchronously, but we may call
Delegate::DidRead synchronously?  That seems like a bad idea.  Always calling
DidRead asynchronously doesn't seem like a great idea, either.

[byungchul, 2014/05/28 01:19:35]

They are different. DidClose() could be called for Close(), but DidRead()
doesn't have a corresponding api. So, hard to say it is synchronous.

+}
+
+void HttpConnection::CloseInNextRunLoop() {

[mmenke, 2014/05/23 19:20:58]

I think this and Close() are misnamed.  Close() should be named
CloseInNextRunLoop (Or better yet, CloseAsync), and this should be called close.

[byungchul, 2014/05/30 00:19:02]

Not necessary. Removed.

+  socket_->Disconnect();
+  delegate_->DidClose(this);
+}
+
+void HttpConnection::UpgradeToWebSocket(const HttpServerRequestInfo& request,
+                                        size_t* pos) {
+  DCHECK(!web_socket_);
+  web_socket_.reset(WebSocket::CreateWebSocket(this, request, pos));
 }
 
 }  // namespace net