Use libevent, second try. Changes this time:

- remove bogus include of base/completion_callback.h
- add DEPS rules to allow including third_party/libevent

Review URL: http://codereview.chromium.org/2964

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@2371 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 345 insertions, 19 deletions

diff --git a/net/DEPS b/net/DEPS
index d048ba2..8883069 100644
--- a/net/DEPS
+++ b/net/DEPS
@@ -1,3 +1,4 @@
 include_rules = [
   "+third_party/modp_b64",
+  "+third_party/libevent",
 ]
diff --git a/net/SConscript b/net/SConscript
index fe95094..4bd5ef7 100644
--- a/net/SConscript
+++ b/net/SConscript
@@ -133,6 +133,7 @@ if env['PLATFORM'] == 'posix':
   input_files.extend([
       # TODO(tc): gnome-vfs? xdgmime? /etc/mime.types?
       'base/platform_mime_util_linux.cc',
+      'base/tcp_client_socket_libevent.cc',
   ])
 
 if env['PLATFORM'] in ('darwin', 'posix'):
@@ -169,6 +170,7 @@ env_tests.Prepend(
         'net',        # net must come before base and modp_b64
         'bzip2',      # bzip2 must come before base
         'base',
+        'event',
         'googleurl',
         'gtest',
         'icuuc',
@@ -224,6 +226,7 @@ unittest_files = [
     'base/net_util_unittest.cc',
     'base/registry_controlled_domain_unittest.cc',
     'base/run_all_unittests.cc',
+    'base/tcp_client_socket_unittest.cc',
     'base/test_completion_callback_unittest.cc',
     'disk_cache/addr_unittest.cc',
     'disk_cache/block_files_unittest.cc',
@@ -242,7 +245,6 @@ if env['PLATFORM'] == 'win32':
       'base/directory_lister_unittest.cc',
       'base/ssl_config_service_unittest.cc',
       'base/ssl_client_socket_unittest.cc',
-      'base/tcp_client_socket_unittest.cc',
       'base/wininet_util_unittest.cc',
       'disk_cache/backend_unittest.cc',
       'http/http_cache_unittest.cc',
diff --git a/net/base/tcp_client_socket.h b/net/base/tcp_client_socket.h
index 06a57fe..96589464 100644
--- a/net/base/tcp_client_socket.h
+++ b/net/base/tcp_client_socket.h
@@ -5,11 +5,21 @@
 #ifndef NET_BASE_TCP_CLIENT_SOCKET_H_
 #define NET_BASE_TCP_CLIENT_SOCKET_H_
 
-#include <ws2tcpip.h>
+#include "build/build_config.h"
 
+#if defined(OS_WIN)
+#include <ws2tcpip.h>
 #include "base/object_watcher.h"
+#elif defined(OS_POSIX)
+struct event;  // From libevent
+#define SOCKET int
+#include "base/message_pump_libevent.h"
+#endif
+
+#include "base/scoped_ptr.h"
 #include "net/base/address_list.h"
 #include "net/base/client_socket.h"
+#include "net/base/completion_callback.h"
 
 namespace net {
 
@@ -18,7 +28,12 @@ namespace net {
 // NOTE: The implementation supports half duplex only.  Read and Write calls
 // must not be in progress at the same time.
 class TCPClientSocket : public ClientSocket,
-                        public base::ObjectWatcher::Delegate {
+#if defined(OS_WIN)
+                        public base::ObjectWatcher::Delegate 
+#elif defined(OS_POSIX)
+                        public base::MessagePumpLibevent::Watcher
+#endif
+{
  public:
   // The IP address(es) and port number to connect to.  The TCP socket will try
   // each IP address in the list until it succeeds in establishing a
@@ -34,31 +49,23 @@ class TCPClientSocket : public ClientSocket,
   virtual bool IsConnected() const;
 
   // Socket methods:
+  // Try to transfer buf_len bytes to/from socket.
+  // If a result is available now, return it; else call back later with one.
+  // Do not call again until a result is returned!
+  // If any bytes were transferred, the result is the byte count.
+  // On error, result is a negative error code; see net/base/net_error_list.h 
+  // TODO: what would a zero return value indicate?
+  // TODO: support multiple outstanding requests?
   virtual int Read(char* buf, int buf_len, CompletionCallback* callback);
   virtual int Write(const char* buf, int buf_len, CompletionCallback* callback);
 
  private:
-  int CreateSocket(const struct addrinfo* ai);
-  void DoCallback(int rv);
-  void DidCompleteConnect();
-  void DidCompleteIO();
-
-  // base::ObjectWatcher::Delegate methods:
-  virtual void OnObjectSignaled(HANDLE object);
-
   SOCKET socket_;
-  OVERLAPPED overlapped_;
-  WSABUF buffer_;
-
-  base::ObjectWatcher watcher_;
-
-  CompletionCallback* callback_;
 
   // The list of addresses we should try in order to establish a connection.
   AddressList addresses_;
 
-  // The addrinfo that we are attempting to use or NULL if all addrinfos have
-  // been tried.
+  // Where we are in above list, or NULL if all addrinfos have been tried.
   const struct addrinfo* current_ai_;
 
   enum WaitState {
@@ -68,6 +75,34 @@ class TCPClientSocket : public ClientSocket,
     WAITING_WRITE
   };
   WaitState wait_state_;
+
+#if defined(OS_WIN)
+  // base::ObjectWatcher::Delegate methods:
+  virtual void OnObjectSignaled(HANDLE object);
+
+  OVERLAPPED overlapped_;
+  WSABUF buffer_;
+
+  base::ObjectWatcher watcher_;
+#elif defined(OS_POSIX)
+  // The socket's libevent wrapper
+  scoped_ptr<event> event_;
+
+  // Called by MessagePumpLibevent when the socket is ready to do I/O
+  void OnSocketReady(short flags);
+
+  // The buffer used by OnSocketReady to retry Read and Write requests
+  char* buf_;
+  int buf_len_;
+#endif
+
+  // External callback; called when read or write is complete.
+  CompletionCallback* callback_;
+
+  int CreateSocket(const struct addrinfo* ai);
+  void DoCallback(int rv);
+  void DidCompleteConnect();
+  void DidCompleteIO();
 };
 
 }  // namespace net
diff --git a/net/base/tcp_client_socket_libevent.cc b/net/base/tcp_client_socket_libevent.cc
new file mode 100644
index 0000000..7f815c3
--- /dev/null
+++ b/net/base/tcp_client_socket_libevent.cc
@@ -0,0 +1,288 @@
+// Copyright (c) 2006-2008 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/base/tcp_client_socket.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <netdb.h>
+#include <sys/socket.h>
+
+#include "base/message_loop.h"
+#include "net/base/net_errors.h"
+#include "third_party/libevent/event.h"
+
+
+namespace net {
+
+const int kInvalidSocket = -1;
+
+// Return 0 on success
+// Too small a function to bother putting in a library?
+static int SetNonBlocking(int fd)
+{
+    int flags = fcntl(fd, F_GETFL, 0);
+    if (-1 == flags)
+      flags = 0;
+    return fcntl(fd, F_SETFL, flags | O_NONBLOCK);
+}
+
+// Convert values from <errno.h> to values from "net/base/net_errors.h"
+static int MapPosixError(int err) {
+  // There are numerous posix error codes, but these are the ones we thus far
+  // find interesting.
+  // TODO(port): fill this with a real conversion table
+  switch (err) {
+    case EWOULDBLOCK: return ERR_IO_PENDING;
+    default:
+      return ERR_FAILED;
+  }
+}
+
+//-----------------------------------------------------------------------------
+
+TCPClientSocket::TCPClientSocket(const AddressList& addresses)
+  : socket_(kInvalidSocket),
+    addresses_(addresses),
+    current_ai_(addresses_.head()),
+    wait_state_(NOT_WAITING),
+    event_(new event) {
+}
+
+TCPClientSocket::~TCPClientSocket() {
+  Disconnect();
+}
+
+int TCPClientSocket::Connect(CompletionCallback* callback) {
+
+  // If already connected, then just return OK.
+  if (socket_ != kInvalidSocket)
+    return OK;
+
+  DCHECK(wait_state_ == NOT_WAITING);
+
+  const addrinfo* ai = current_ai_;
+  DCHECK(ai);
+
+  int rv = CreateSocket(ai);
+  if (rv != OK)
+    return rv;
+
+  if (!connect(socket_, ai->ai_addr, static_cast<int>(ai->ai_addrlen))) {
+    // Connected without waiting!
+    return OK;
+  }
+
+  // Synchronous operation not supported
+  DCHECK(callback);
+
+  if (errno != EINPROGRESS && errno != EWOULDBLOCK) {
+    LOG(ERROR) << "connect failed: " << errno;
+    return MapPosixError(errno);
+  }
+
+  // Initialize event_ and link it to our MessagePump.
+  // POLLOUT is set if the connection is established.
+  // POLLIN is set if the connection fails,
+  // so select for both read and write.
+  MessageLoopForIO::current()->WatchSocket(
+     socket_, EV_READ|EV_WRITE|EV_PERSIST, event_.get(), this);
+
+  wait_state_ = WAITING_CONNECT;
+  callback_ = callback;
+  return ERR_IO_PENDING;
+}
+
+int TCPClientSocket::ReconnectIgnoringLastError(CompletionCallback* callback) {
+  // No ignorable errors!
+  return ERR_FAILED;
+}
+
+void TCPClientSocket::Disconnect() {
+  if (socket_ == kInvalidSocket)
+    return;
+
+  MessageLoopForIO::current()->UnwatchSocket(event_.get());
+  close(socket_);
+  socket_ = kInvalidSocket;
+
+  // Reset for next time.
+  current_ai_ = addresses_.head();
+}
+
+bool TCPClientSocket::IsConnected() const {
+  if (socket_ == kInvalidSocket || wait_state_ == WAITING_CONNECT)
+    return false;
+
+  // Check if connection is alive.
+  char c;
+  int rv = recv(socket_, &c, 1, MSG_PEEK);
+  if (rv == 0)
+    return false;
+
+  return true;
+}
+
+int TCPClientSocket::Read(char* buf,
+                          int buf_len,
+                          CompletionCallback* callback) {
+  DCHECK(socket_ != kInvalidSocket);
+  DCHECK(wait_state_ == NOT_WAITING);
+  DCHECK(!callback_);
+  // Synchronous operation not supported
+  DCHECK(callback);
+  DCHECK(buf_len > 0);
+
+  int nread = read(socket_, buf, buf_len);
+  if (nread > 0) {
+    return nread;
+  }
+  if (nread == -1 && errno != EWOULDBLOCK)
+    return MapPosixError(errno);
+
+  MessageLoopForIO::current()->WatchSocket(
+     socket_, EV_READ|EV_PERSIST, event_.get(), this);
+
+  buf_ = buf;
+  buf_len_ = buf_len;
+  wait_state_ = WAITING_READ;
+  callback_ = callback;
+  return ERR_IO_PENDING;
+}
+
+int TCPClientSocket::Write(const char* buf,
+                           int buf_len,
+                           CompletionCallback* callback) {
+  DCHECK(socket_ != kInvalidSocket);
+  DCHECK(wait_state_ == NOT_WAITING);
+  DCHECK(!callback_);
+  // Synchronous operation not supported
+  DCHECK(callback);
+  DCHECK(buf_len > 0);
+
+  int nwrite = write(socket_, buf, buf_len);
+  if (nwrite > 0) {
+    return nwrite;
+  }
+  if (nwrite == -1 && errno != EWOULDBLOCK)
+    return MapPosixError(errno);
+
+  MessageLoopForIO::current()->WatchSocket(
+     socket_, EV_WRITE|EV_PERSIST, event_.get(), this);
+
+  buf_ = const_cast<char*>(buf);
+  buf_len_ = buf_len;
+  wait_state_ = WAITING_WRITE;
+  callback_ = callback;
+  return ERR_IO_PENDING;
+}
+
+int TCPClientSocket::CreateSocket(const addrinfo* ai) {
+  socket_ = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
+  if (socket_ == kInvalidSocket)
+    return MapPosixError(errno);
+
+  // All our socket I/O is nonblocking
+  if (SetNonBlocking(socket_))
+    return MapPosixError(errno);
+  
+  return OK;
+}
+
+void TCPClientSocket::DoCallback(int rv) {
+  DCHECK(rv != ERR_IO_PENDING);
+  DCHECK(callback_);
+
+  // since Run may result in Read being called, clear callback_ up front.
+  CompletionCallback* c = callback_;
+  callback_ = NULL;
+  c->Run(rv);
+}
+
+void TCPClientSocket::DidCompleteConnect() {
+  int result = ERR_UNEXPECTED;
+
+  wait_state_ = NOT_WAITING;
+
+  // Check to see if connect succeeded
+  int error_code = -1;
+  socklen_t len = sizeof(error_code);
+  if (getsockopt(socket_, SOL_SOCKET, SO_ERROR, 
+                 reinterpret_cast<char*>(&error_code), &len) < 0) {
+    result = MapPosixError(errno);
+  } else if (error_code == EINPROGRESS) {
+    result = ERR_IO_PENDING;
+    // And await next callback.  Haven't seen this case yet myself.
+  } else if (current_ai_->ai_next && (
+             error_code == EADDRNOTAVAIL ||
+             error_code == EAFNOSUPPORT ||
+             error_code == ECONNREFUSED ||
+             error_code == ENETUNREACH ||
+             error_code == EHOSTUNREACH ||
+             error_code == ETIMEDOUT)) {
+    // This address failed, try next one in list.  
+    const addrinfo* next = current_ai_->ai_next;
+    Disconnect();
+    current_ai_ = next;
+    result = Connect(callback_);
+  } else if (error_code) {
+    result = MapPosixError(error_code);
+  } else {
+    result = 0;
+    MessageLoopForIO::current()->UnwatchSocket(event_.get());
+  }
+
+  if (result != ERR_IO_PENDING)
+    DoCallback(result);
+}
+
+void TCPClientSocket::DidCompleteIO() {
+  int bytes_transferred;
+  switch (wait_state_) {
+    case WAITING_READ:
+      bytes_transferred = read(socket_, buf_, buf_len_);
+      break;
+    case WAITING_WRITE:
+      bytes_transferred = write(socket_, buf_, buf_len_);
+      break;
+    default:
+      NOTREACHED();
+  }
+
+  int result;
+  if (bytes_transferred > 0) {
+    result = bytes_transferred;
+  } else if (bytes_transferred == 0) {
+    // TODO(port): can we tell why it closed, and return a more informative 
+    // message?  And why does the unit test want to see zero?
+    //result = ERR_CONNECTION_CLOSED;
+    result = 0;
+  } else {
+    result = MapPosixError(errno);
+  }
+
+  if (result != ERR_IO_PENDING) {
+    wait_state_ = NOT_WAITING;
+    MessageLoopForIO::current()->UnwatchSocket(event_.get());
+    DoCallback(result);
+  }
+}
+
+void TCPClientSocket::OnSocketReady(short flags) {
+  switch (wait_state_) {
+    case WAITING_CONNECT:
+      DidCompleteConnect();
+      break;
+    case WAITING_READ:
+    case WAITING_WRITE:
+      DidCompleteIO();
+      break;
+    default:
+      NOTREACHED();
+      break;
+  }
+}
+
+}  // namespace net
+