base/message_pump_io_ios.h

   1 // Copyright 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef BASE_MESSAGE_PUMP_IO_IOS_H_
   6 #define BASE_MESSAGE_PUMP_IO_IOS_H_
   7
   8 #include "base/base_export.h"
   9 #include "base/mac/scoped_cffiledescriptorref.h"
  10 #include "base/mac/scoped_cftyperef.h"
  11 #include "base/memory/ref_counted.h"
  12 #include "base/message_pump_mac.h"
  13 #include "base/observer_list.h"
  14
  15 namespace base {
  16
  17 // This file introduces a class to monitor sockets and issue callbacks when
  18 // sockets are ready for I/O on iOS.
  19 class BASE_EXPORT MessagePumpIOSForIO : public MessagePumpNSRunLoop {
  20  public:
  21   class IOObserver {
  22    public:
  23     IOObserver() {}
  24
  25     // An IOObserver is an object that receives IO notifications from the
  26     // MessagePump.
  27     //
  28     // NOTE: An IOObserver implementation should be extremely fast!
  29     virtual void WillProcessIOEvent() = 0;
  30     virtual void DidProcessIOEvent() = 0;
  31
  32    protected:
  33     virtual ~IOObserver() {}
  34   };
  35
  36   // Used with WatchFileDescriptor to asynchronously monitor the I/O readiness
  37   // of a file descriptor.
  38   class Watcher {
  39    public:
  40     // Called from MessageLoop::Run when an FD can be read from/written to
  41     // without blocking
  42     virtual void OnFileCanReadWithoutBlocking(int fd) = 0;
  43     virtual void OnFileCanWriteWithoutBlocking(int fd) = 0;
  44
  45    protected:
  46     virtual ~Watcher() {}
  47   };
  48
  49   // Object returned by WatchFileDescriptor to manage further watching.
  50   class FileDescriptorWatcher {
  51    public:
  52     FileDescriptorWatcher();
  53     ~FileDescriptorWatcher();  // Implicitly calls StopWatchingFileDescriptor.
  54
  55     // NOTE: These methods aren't called StartWatching()/StopWatching() to
  56     // avoid confusion with the win32 ObjectWatcher class.
  57
  58     // Stop watching the FD, always safe to call.  No-op if there's nothing
  59     // to do.
  60     bool StopWatchingFileDescriptor();
  61
  62    private:
  63     friend class MessagePumpIOSForIO;
  64     friend class MessagePumpIOSForIOTest;
  65
  66     // Called by MessagePumpIOSForIO, ownership of |fdref| and |fd_source|
  67     // is transferred to this object.
  68     void Init(CFFileDescriptorRef fdref,
  69               CFOptionFlags callback_types,
  70               CFRunLoopSourceRef fd_source,
  71               bool is_persistent);
  72
  73     void set_pump(MessagePumpIOSForIO* pump) { pump_ = pump; }
  74     MessagePumpIOSForIO* pump() const { return pump_; }
  75
  76     void set_watcher(Watcher* watcher) { watcher_ = watcher; }
  77
  78     void OnFileCanReadWithoutBlocking(int fd, MessagePumpIOSForIO* pump);
  79     void OnFileCanWriteWithoutBlocking(int fd, MessagePumpIOSForIO* pump);
  80
  81     bool is_persistent_;  // false if this event is one-shot.
  82     base::mac::ScopedCFFileDescriptorRef fdref_;
  83     CFOptionFlags callback_types_;
  84     base::mac::ScopedCFTypeRef<CFRunLoopSourceRef> fd_source_;
  85     scoped_refptr<MessagePumpIOSForIO> pump_;
  86     Watcher* watcher_;
  87
  88     DISALLOW_COPY_AND_ASSIGN(FileDescriptorWatcher);
  89   };
  90
  91   enum Mode {
  92     WATCH_READ = 1 << 0,
  93     WATCH_WRITE = 1 << 1,
  94     WATCH_READ_WRITE = WATCH_READ | WATCH_WRITE
  95   };
  96
  97   MessagePumpIOSForIO();
  98
  99   // Have the current thread's message loop watch for a a situation in which
 100   // reading/writing to the FD can be performed without blocking.
 101   // Callers must provide a preallocated FileDescriptorWatcher object which
 102   // can later be used to manage the lifetime of this event.
 103   // If a FileDescriptorWatcher is passed in which is already attached to
 104   // an event, then the effect is cumulative i.e. after the call |controller|
 105   // will watch both the previous event and the new one.
 106   // If an error occurs while calling this method in a cumulative fashion, the
 107   // event previously attached to |controller| is aborted.
 108   // Returns true on success.
 109   // Must be called on the same thread the message_pump is running on.
 110   bool WatchFileDescriptor(int fd,
 111                            bool persistent,
 112                            int mode,
 113                            FileDescriptorWatcher *controller,
 114                            Watcher *delegate);
 115
 116   void RemoveRunLoopSource(CFRunLoopSourceRef source);
 117
 118   void AddIOObserver(IOObserver* obs);
 119   void RemoveIOObserver(IOObserver* obs);
 120
 121  protected:
 122   virtual ~MessagePumpIOSForIO();
 123
 124  private:
 125   friend class MessagePumpIOSForIOTest;
 126
 127   void WillProcessIOEvent();
 128   void DidProcessIOEvent();
 129
 130   static void HandleFdIOEvent(CFFileDescriptorRef fdref,
 131                               CFOptionFlags callback_types,
 132                               void* context);
 133
 134   ObserverList<IOObserver> io_observers_;
 135   ThreadChecker watch_file_descriptor_caller_checker_;
 136
 137   DISALLOW_COPY_AND_ASSIGN(MessagePumpIOSForIO);
 138 };
 139
 140 }  // namespace base
 141
 142 #endif  // BASE_MESSAGE_PUMP_IO_IOS_H_