Initial work for UDP Pepper API

ppapi/proxy/ppb_flash_udp_socket_proxy.cc

+// Copyright (c) 2011 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 "ppapi/proxy/ppb_flash_udp_socket_proxy.h"
+
+#include <algorithm>
+#include <cstring>
+#include <map>
+
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/message_loop.h"
+#include "base/task.h"
+#include "ppapi/c/pp_errors.h"
+#include "ppapi/proxy/plugin_dispatcher.h"
+#include "ppapi/proxy/plugin_resource_tracker.h"
+#include "ppapi/proxy/ppapi_messages.h"
+#include "ppapi/shared_impl/resource.h"
+#include "ppapi/thunk/ppb_flash_udp_socket_api.h"
+#include "ppapi/thunk/thunk.h"
+
+using ppapi::thunk::PPB_Flash_UDPSocket_API;
+
+namespace ppapi {
+namespace proxy {
+
+const int32_t kFlashUDPSocketMaxReadSize = 1024 * 1024;
+const int32_t kFlashUDPSocketMaxWriteSize = 1024 * 1024;
+
+class FlashUDPSocket;
+
+namespace {
+
+typedef std::map<uint32, FlashUDPSocket*> IDToSocketMap;
+IDToSocketMap* g_id_to_socket = NULL;
+
+class AbortCallbackTask : public Task {
+ public:
+  explicit AbortCallbackTask(PP_CompletionCallback callback)
+      : callback_(callback) {}
+  virtual ~AbortCallbackTask() {}
+  virtual void Run() {
+    if (callback_.func)
+      PP_RunCompletionCallback(&callback_, PP_ERROR_ABORTED);
+  }
+
+ private:
+  PP_CompletionCallback callback_;
+};
+
+InterfaceProxy* CreateFlashUDPSocketProxy(Dispatcher* dispatcher) {
+  return new PPB_Flash_UDPSocket_Proxy(dispatcher);
+}
+
+}  // namespace
+
+class FlashUDPSocket : public PPB_Flash_UDPSocket_API,

[brettw, 2011/09/22 20:03:30]

I think this class can be in the anonymous namespace since it's only used in
this .cc file.

[mtilburg, 2011/09/23 17:30:28]

Done.

+                       public Resource {
+ public:
+  FlashUDPSocket(const HostResource& resource, uint32 socket_id);
+  virtual ~FlashUDPSocket();
+
+  // ResourceObjectBase overrides.
+  virtual PPB_Flash_UDPSocket_API* AsPPB_Flash_UDPSocket_API() OVERRIDE;
+
+  // PPB_Flash_UDPSocket_API implementation.
+  virtual int32_t Bind(const PP_Flash_NetAddress* addr,
+                       PP_CompletionCallback callback) OVERRIDE;
+  virtual int32_t RecvFrom(char* buffer,
+                           int32_t num_bytes,
+                           PP_CompletionCallback callback) OVERRIDE;
+  virtual PP_Bool GetRecvFromAddress(PP_Flash_NetAddress* addr) OVERRIDE;
+
+  virtual int32_t SendTo(const char* buffer,
+                         int32_t num_bytes,
+                         const PP_Flash_NetAddress* addr,
+                         PP_CompletionCallback callback) OVERRIDE;
+  virtual void Close() OVERRIDE;
+
+  // Notifications from the proxy.
+  void OnBindCompleted(bool succeeded);
+  void OnRecvFromCompleted(bool succeeded,
+                           const std::string& data,
+                           const PP_Flash_NetAddress& addr);
+  void OnSendToCompleted(bool succeeded,
+                         int32_t bytes_written);
+
+ private:
+  void PostAbortAndClearIfNecessary(PP_CompletionCallback* callback);
+
+  PluginDispatcher* GetDispatcher() const {
+    return PluginDispatcher::GetForResource(this);
+  }
+
+  uint32 socket_id_;
+
+  bool binded_;
+
+  PP_CompletionCallback bind_callback_;
+  PP_CompletionCallback recvfrom_callback_;
+  PP_CompletionCallback sendto_callback_;
+
+  char* read_buffer_;
+  int32_t bytes_to_read_;
+
+  PP_Flash_NetAddress recvfrom_addr_;
+
+  DISALLOW_COPY_AND_ASSIGN(FlashUDPSocket);
+};
+
+FlashUDPSocket::FlashUDPSocket(const HostResource& resource,
+                               uint32 socket_id)
+    : Resource(resource),
+      socket_id_(socket_id),
+      binded_(false),
+      bind_callback_(PP_BlockUntilComplete()),
+      recvfrom_callback_(PP_BlockUntilComplete()),
+      sendto_callback_(PP_BlockUntilComplete()),
+      read_buffer_(NULL),
+      bytes_to_read_(-1) {
+  DCHECK(socket_id != 0);
+
+  recvfrom_addr_.size = 0;
+  memset(recvfrom_addr_.data, 0, sizeof(recvfrom_addr_.data));
+
+  if (!g_id_to_socket)
+    g_id_to_socket = new IDToSocketMap();
+  DCHECK(g_id_to_socket->find(socket_id) == g_id_to_socket->end());
+  (*g_id_to_socket)[socket_id] = this;
+}
+
+FlashUDPSocket::~FlashUDPSocket() {
+  Close();
+}
+
+PPB_Flash_UDPSocket_API* FlashUDPSocket::AsPPB_Flash_UDPSocket_API() {
+  return this;
+}
+
+int32_t FlashUDPSocket::Bind(const PP_Flash_NetAddress* addr,
+                             PP_CompletionCallback callback) {
+  if (!addr || !callback.func)
+    return PP_ERROR_BADARGUMENT;
+  if (binded_)
+    return PP_ERROR_FAILED;
+  if (bind_callback_.func)
+    return PP_ERROR_INPROGRESS;
+
+  bind_callback_ = callback;
+
+  GetDispatcher()->SendToBrowser(
+      new PpapiHostMsg_PPBFlashUDPSocket_Bind(socket_id_, *addr));
+
+  return PP_OK_COMPLETIONPENDING;
+}
+
+int32_t FlashUDPSocket::RecvFrom(char* buffer,
+                                 int32_t num_bytes,
+                                 PP_CompletionCallback callback) {
+  if (!buffer || num_bytes <= 0 || !callback.func)
+    return PP_ERROR_BADARGUMENT;
+
+  if (recvfrom_callback_.func)
+    return PP_ERROR_INPROGRESS;
+
+  read_buffer_ = buffer;
+  bytes_to_read_ = std::min(num_bytes, kFlashUDPSocketMaxReadSize);
+  recvfrom_callback_ = callback;
+
+  // Send the request, the browser will call us back via RecvFromACK.
+  GetDispatcher()->SendToBrowser(
+      new PpapiHostMsg_PPBFlashUDPSocket_RecvFrom(
+          socket_id_, num_bytes));
+  return PP_OK_COMPLETIONPENDING;
+}
+
+PP_Bool FlashUDPSocket::GetRecvFromAddress(PP_Flash_NetAddress* addr) {
+  if (!addr)
+    return PP_FALSE;
+
+  *addr = recvfrom_addr_;
+  return PP_TRUE;
+}
+
+int32_t FlashUDPSocket::SendTo(const char* buffer,
+                               int32_t num_bytes,
+                               const PP_Flash_NetAddress* addr,
+                               PP_CompletionCallback callback) {
+  if (!buffer || num_bytes <= 0 || !addr || !callback.func)
+    return PP_ERROR_BADARGUMENT;
+  if (sendto_callback_.func)
+    return PP_ERROR_INPROGRESS;
+
+  if (num_bytes > kFlashUDPSocketMaxWriteSize)
+    num_bytes = kFlashUDPSocketMaxWriteSize;
+
+  sendto_callback_ = callback;
+
+  // Send the request, the browser will call us back via SendToACK.
+  GetDispatcher()->SendToBrowser(
+      new PpapiHostMsg_PPBFlashUDPSocket_SendTo(
+          socket_id_, std::string(buffer, num_bytes), *addr));
+
+  return PP_OK_COMPLETIONPENDING;
+}
+
+void FlashUDPSocket::Close() {
+  if (!binded_)

[yzshen1, 2011/09/22 20:07:04]

It is not right to use binded_ to decide whether Close should be executed or
not. According to the current implementation, Close line 214 and below needs to
be run exactly once for an FlashUDPSocket.

Let's consider the following examples:
1) create a FlashUDPSocket object, and then destruct it directly: you leave an
invalid entry in g_id_to_socket.
2) create a FlashUDPSocket object, call Bind, before the bind finishes you
destruct the object -> you leave an invalid entry in g_id_to_socket and an
uncalled completion callback.

Something else to consider:
What happens if
1) the user calls Bind(), and it succeeds;
2) and then the user calls Close();
3) and then the user calls other operations (Bind/SendTo/RecvFrom).
Do you need to fail those operations directly?
According to the current logic, the browser process will delete the socket stuff
at its side directly when it receives PpapiHostMsg_PPBFlashUDPSocket_Close.

If you allow other operations after Close(), they will never finish. And you
will get assertion in the browser process because it has no idea about the
socket_id any more.

[mtilburg, 2011/09/23 17:30:28]

I've added checks at the beginning of Bind/SendTo/RecvFrom to check the binded_
bool.  for Bind, binded_ must be false(so not to allow a second bind on the same
socket) For SendTo and RecvFrom, binded_ must be true, so these operations will
not be allowed unless bind has been called and succeeded.

As for Close, I will not check the binded_ bool, but I will set it to false, so
that no more operations can occur.

I think this should satisfy all the requirements?
On 2011/09/22 20:07:04, yzshen1 wrote:

[yzshen1, 2011/09/23 18:06:58]

No. Please note that line 212-223 is teardown code that must be executed
*exactly once* for the object. And after that point, no operation
(Bind/SendTo/RecvFrom) will succeed, because the browser has forgotten this
socket_id_. (The code will hit NOTREACHED in pepper_message_filter.cc)

As I said, you could have a |closed_| boolean to guard that the logic is
execuated exactly once. And you need to test |closed_| in Bind() so that we will
not try to store the completion callback of Bind if Close has been called.
(Otherwise, that completion callback will never be called. This should be avoid,
because Pepper requires that if we have returned PP_OK_COMPLETIONPENDING, the
callback must be called exactly once later.)

This is one of the feasible approaches, but seems to be the one with minimal
change.

If you would like to, we could have a dicussion over phone. Hopefully that will
be more clear. I think this change is very close to completion now.

[mtilburg, 2011/09/23 18:36:55]

Okay, I added closed_, and check it before I execute this code so that it is
only executed once...  I also added a check in Bind so that we will not re-bind
the socket if it has already been closed.  The binded_ bool is still necessary
to make sure that sendto and recvfrom are not executed unless bind has been
successful
On 2011/09/23 18:06:58, yzshen1 wrote:

+    return;
+
+  binded_ = false;
+
+  // After removed from the mapping, this object won't receive any notfications
+  // from the proxy.
+  DCHECK(g_id_to_socket->find(socket_id_) != g_id_to_socket->end());
+  g_id_to_socket->erase(socket_id_);
+
+  GetDispatcher()->SendToBrowser(
+      new PpapiHostMsg_PPBFlashUDPSocket_Close(socket_id_));
+  socket_id_ = 0;
+
+  PostAbortAndClearIfNecessary(&bind_callback_);
+  PostAbortAndClearIfNecessary(&recvfrom_callback_);
+  PostAbortAndClearIfNecessary(&sendto_callback_);
+}
+
+void FlashUDPSocket::OnBindCompleted(bool succeeded) {
+  if (!bind_callback_.func) {
+    NOTREACHED();
+    return;
+  }
+
+  if (succeeded)
+    binded_ = true;
+
+  PP_RunAndClearCompletionCallback(&bind_callback_,
+                                   succeeded ? PP_OK : PP_ERROR_FAILED);
+}
+
+void FlashUDPSocket::OnRecvFromCompleted(bool succeeded,
+                                         const std::string& data,
+                                         const PP_Flash_NetAddress& addr) {
+  if (!recvfrom_callback_.func || !read_buffer_) {
+    NOTREACHED();
+    return;
+  }
+
+  if (succeeded) {
+    CHECK_LE(static_cast<int32_t>(data.size()), bytes_to_read_);
+    if (!data.empty())
+      memcpy(read_buffer_, data.c_str(), data.size());
+  }
+  read_buffer_ = NULL;
+  bytes_to_read_ = -1;
+  recvfrom_addr_ = addr;
+
+  PP_RunAndClearCompletionCallback(
+      &recvfrom_callback_,
+      succeeded ? static_cast<int32_t>(data.size()) :
+                  static_cast<int32_t>(PP_ERROR_FAILED));
+}
+
+void FlashUDPSocket::OnSendToCompleted(bool succeeded,
+                                       int32_t bytes_written) {
+  if (!sendto_callback_.func) {
+    NOTREACHED();
+    return;
+  }
+
+  PP_RunAndClearCompletionCallback(
+      &sendto_callback_,
+      succeeded ? bytes_written : static_cast<int32_t>(PP_ERROR_FAILED));
+}
+
+void FlashUDPSocket::PostAbortAndClearIfNecessary(
+    PP_CompletionCallback* callback) {
+  DCHECK(callback);
+
+  if (callback->func) {
+    MessageLoop::current()->PostTask(FROM_HERE,
+                                     new AbortCallbackTask(*callback));
+    *callback = PP_BlockUntilComplete();
+  }
+}
+
+PPB_Flash_UDPSocket_Proxy::PPB_Flash_UDPSocket_Proxy(Dispatcher* dispatcher)
+    : InterfaceProxy(dispatcher) {
+}
+
+PPB_Flash_UDPSocket_Proxy::~PPB_Flash_UDPSocket_Proxy() {
+}
+
+// static
+const InterfaceProxy::Info* PPB_Flash_UDPSocket_Proxy::GetInfo() {
+  static const Info info = {
+    ::ppapi::thunk::GetPPB_Flash_UDPSocket_Thunk(),
+    PPB_FLASH_UDPSOCKET_INTERFACE,
+    INTERFACE_ID_PPB_FLASH_UDPSOCKET,
+    false,
+    &CreateFlashUDPSocketProxy,
+  };
+  return &info;
+}
+
+// static
+PP_Resource PPB_Flash_UDPSocket_Proxy::CreateProxyResource(
+    PP_Instance instance) {
+  PluginDispatcher* dispatcher = PluginDispatcher::GetForInstance(instance);
+  if (!dispatcher)
+    return 0;
+
+  uint32 socket_id = 0;
+  dispatcher->SendToBrowser(new PpapiHostMsg_PPBFlashUDPSocket_Create(
+      INTERFACE_ID_PPB_FLASH_UDPSOCKET, dispatcher->plugin_dispatcher_id(),
+      &socket_id));
+  if (socket_id == 0)
+    return 0;
+
+  return (new FlashUDPSocket(HostResource::MakeInstanceOnly(instance),
+                             socket_id))->GetReference();
+}
+
+bool PPB_Flash_UDPSocket_Proxy::OnMessageReceived(const IPC::Message& msg) {
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP(PPB_Flash_UDPSocket_Proxy, msg)
+    IPC_MESSAGE_HANDLER(PpapiMsg_PPBFlashUDPSocket_BindACK,
+                        OnMsgBindACK)
+    IPC_MESSAGE_HANDLER(PpapiMsg_PPBFlashUDPSocket_RecvFromACK,
+                        OnMsgRecvFromACK)
+    IPC_MESSAGE_HANDLER(PpapiMsg_PPBFlashUDPSocket_SendToACK,
+                        OnMsgSendToACK)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+  return handled;
+}
+
+void PPB_Flash_UDPSocket_Proxy::OnMsgBindACK(
+    uint32 /* plugin_dispatcher_id */,
+    uint32 socket_id,
+    bool succeeded) {
+  if (!g_id_to_socket) {
+    NOTREACHED();
+    return;
+  }
+  IDToSocketMap::iterator iter = g_id_to_socket->find(socket_id);
+  if (iter == g_id_to_socket->end())
+    return;
+  iter->second->OnBindCompleted(succeeded);
+}
+
+void PPB_Flash_UDPSocket_Proxy::OnMsgRecvFromACK(
+    uint32 /* plugin_dispatcher_id */,
+    uint32 socket_id,
+    bool succeeded,
+    const std::string& data,
+    const PP_Flash_NetAddress& addr) {
+  if (!g_id_to_socket) {
+    NOTREACHED();
+    return;
+  }
+  IDToSocketMap::iterator iter = g_id_to_socket->find(socket_id);
+  if (iter == g_id_to_socket->end())
+    return;
+  iter->second->OnRecvFromCompleted(succeeded, data, addr);
+}
+
+void PPB_Flash_UDPSocket_Proxy::OnMsgSendToACK(
+    uint32 /* plugin_dispatcher_id */,
+    uint32 socket_id,
+    bool succeeded,
+    int32_t bytes_written) {
+  if (!g_id_to_socket) {
+    NOTREACHED();
+    return;
+  }
+  IDToSocketMap::iterator iter = g_id_to_socket->find(socket_id);
+  if (iter == g_id_to_socket->end())
+    return;
+  iter->second->OnSendToCompleted(succeeded, bytes_written);
+}
+
+}  // namespace proxy
+}  // namespace ppapi
+