ipc/ipc_message.h

   1 // Copyright (c) 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 IPC_IPC_MESSAGE_H_
   6 #define IPC_IPC_MESSAGE_H_
   7
   8 #include <string>
   9
  10 #include "base/basictypes.h"
  11 #include "base/debug/trace_event.h"
  12 #include "base/files/file.h"
  13 #include "base/pickle.h"
  14 #include "ipc/ipc_export.h"
  15
  16 #if !defined(NDEBUG)
  17 #define IPC_MESSAGE_LOG_ENABLED
  18 #endif
  19
  20 #if defined(OS_POSIX)
  21 #include "base/memory/ref_counted.h"
  22 #endif
  23
  24 class FileDescriptorSet;
  25
  26 namespace IPC {
  27
  28 //------------------------------------------------------------------------------
  29
  30 struct LogData;
  31
  32 class IPC_EXPORT Message : public Pickle {
  33  public:
  34   enum PriorityValue {
  35     PRIORITY_LOW = 1,
  36     PRIORITY_NORMAL,
  37     PRIORITY_HIGH
  38   };
  39
  40   // Bit values used in the flags field.
  41   // Upper 24 bits of flags store a reference number, so this enum is limited to
  42   // 8 bits.
  43   enum {
  44     PRIORITY_MASK     = 0x03,  // Low 2 bits of store the priority value.
  45     SYNC_BIT          = 0x04,
  46     REPLY_BIT         = 0x08,
  47     REPLY_ERROR_BIT   = 0x10,
  48     UNBLOCK_BIT       = 0x20,
  49     PUMPING_MSGS_BIT  = 0x40,
  50     HAS_SENT_TIME_BIT = 0x80,
  51   };
  52
  53   virtual ~Message();
  54
  55   Message();
  56
  57   // Initialize a message with a user-defined type, priority value, and
  58   // destination WebView ID.
  59   Message(int32 routing_id, uint32 type, PriorityValue priority);
  60
  61   // Initializes a message from a const block of data.  The data is not copied;
  62   // instead the data is merely referenced by this message.  Only const methods
  63   // should be used on the message when initialized this way.
  64   Message(const char* data, int data_len);
  65
  66   Message(const Message& other);
  67   Message& operator=(const Message& other);
  68
  69   PriorityValue priority() const {
  70     return static_cast<PriorityValue>(header()->flags & PRIORITY_MASK);
  71   }
  72
  73   // True if this is a synchronous message.
  74   void set_sync() {
  75     header()->flags |= SYNC_BIT;
  76   }
  77   bool is_sync() const {
  78     return (header()->flags & SYNC_BIT) != 0;
  79   }
  80
  81   // Set this on a reply to a synchronous message.
  82   void set_reply() {
  83     header()->flags |= REPLY_BIT;
  84   }
  85
  86   bool is_reply() const {
  87     return (header()->flags & REPLY_BIT) != 0;
  88   }
  89
  90   // Set this on a reply to a synchronous message to indicate that no receiver
  91   // was found.
  92   void set_reply_error() {
  93     header()->flags |= REPLY_ERROR_BIT;
  94   }
  95
  96   bool is_reply_error() const {
  97     return (header()->flags & REPLY_ERROR_BIT) != 0;
  98   }
  99
 100   // Normally when a receiver gets a message and they're blocked on a
 101   // synchronous message Send, they buffer a message.  Setting this flag causes
 102   // the receiver to be unblocked and the message to be dispatched immediately.
 103   void set_unblock(bool unblock) {
 104     if (unblock) {
 105       header()->flags |= UNBLOCK_BIT;
 106     } else {
 107       header()->flags &= ~UNBLOCK_BIT;
 108     }
 109   }
 110
 111   bool should_unblock() const {
 112     return (header()->flags & UNBLOCK_BIT) != 0;
 113   }
 114
 115   // Tells the receiver that the caller is pumping messages while waiting
 116   // for the result.
 117   bool is_caller_pumping_messages() const {
 118     return (header()->flags & PUMPING_MSGS_BIT) != 0;
 119   }
 120
 121   void set_dispatch_error() const {
 122     dispatch_error_ = true;
 123   }
 124
 125   bool dispatch_error() const {
 126     return dispatch_error_;
 127   }
 128
 129   uint32 type() const {
 130     return header()->type;
 131   }
 132
 133   int32 routing_id() const {
 134     return header()->routing;
 135   }
 136
 137   void set_routing_id(int32 new_id) {
 138     header()->routing = new_id;
 139   }
 140
 141   uint32 flags() const {
 142     return header()->flags;
 143   }
 144
 145   // Sets all the given header values. The message should be empty at this
 146   // call.
 147   void SetHeaderValues(int32 routing, uint32 type, uint32 flags);
 148
 149   template<class T, class S, class P>
 150   static bool Dispatch(const Message* msg, T* obj, S* sender, P* parameter,
 151                        void (T::*func)()) {
 152     (obj->*func)();
 153     return true;
 154   }
 155
 156   template<class T, class S, class P>
 157   static bool Dispatch(const Message* msg, T* obj, S* sender, P* parameter,
 158                        void (T::*func)(P*)) {
 159     (obj->*func)(parameter);
 160     return true;
 161   }
 162
 163   // Used for async messages with no parameters.
 164   static void Log(std::string* name, const Message* msg, std::string* l) {
 165   }
 166
 167   // Find the end of the message data that starts at range_start.  Returns NULL
 168   // if the entire message is not found in the given data range.
 169   static const char* FindNext(const char* range_start, const char* range_end) {
 170     return Pickle::FindNext(sizeof(Header), range_start, range_end);
 171   }
 172
 173 #if defined(OS_POSIX)
 174   // On POSIX, a message supports reading / writing FileDescriptor objects.
 175   // This is used to pass a file descriptor to the peer of an IPC channel.
 176
 177   // Add a descriptor to the end of the set. Returns false if the set is full.
 178   bool WriteFile(base::ScopedFD descriptor);
 179   bool WriteBorrowingFile(const base::PlatformFile& descriptor);
 180
 181   // Get a file descriptor from the message. Returns false on error.
 182   //   iter: a Pickle iterator to the current location in the message.
 183   bool ReadFile(PickleIterator* iter, base::ScopedFD* file) const;
 184
 185   // Returns true if there are any file descriptors in this message.
 186   bool HasFileDescriptors() const;
 187 #endif
 188
 189 #ifdef IPC_MESSAGE_LOG_ENABLED
 190   // Adds the outgoing time from Time::Now() at the end of the message and sets
 191   // a bit to indicate that it's been added.
 192   void set_sent_time(int64 time);
 193   int64 sent_time() const;
 194
 195   void set_received_time(int64 time) const;
 196   int64 received_time() const { return received_time_; }
 197   void set_output_params(const std::string& op) const { output_params_ = op; }
 198   const std::string& output_params() const { return output_params_; }
 199   // The following four functions are needed so we can log sync messages with
 200   // delayed replies.  We stick the log data from the sent message into the
 201   // reply message, so that when it's sent and we have the output parameters
 202   // we can log it.  As such, we set a flag on the sent message to not log it.
 203   void set_sync_log_data(LogData* data) const { log_data_ = data; }
 204   LogData* sync_log_data() const { return log_data_; }
 205   void set_dont_log() const { dont_log_ = true; }
 206   bool dont_log() const { return dont_log_; }
 207 #endif
 208
 209   // Called to trace when message is sent.
 210   void TraceMessageBegin() {
 211     TRACE_EVENT_FLOW_BEGIN0(TRACE_DISABLED_BY_DEFAULT("ipc.flow"), "IPC",
 212         header()->flags);
 213   }
 214   // Called to trace when message is received.
 215   void TraceMessageEnd() {
 216     TRACE_EVENT_FLOW_END0(TRACE_DISABLED_BY_DEFAULT("ipc.flow"), "IPC",
 217         header()->flags);
 218   }
 219
 220  protected:
 221   friend class Channel;
 222   friend class ChannelMojo;
 223   friend class ChannelNacl;
 224   friend class ChannelPosix;
 225   friend class ChannelWin;
 226   friend class MessageReplyDeserializer;
 227   friend class SyncMessage;
 228
 229 #pragma pack(push, 4)
 230   struct Header : Pickle::Header {
 231     int32 routing;  // ID of the view that this message is destined for
 232     uint32 type;    // specifies the user-defined message type
 233     uint32 flags;   // specifies control flags for the message
 234 #if defined(OS_POSIX)
 235     uint16 num_fds; // the number of descriptors included with this message
 236     uint16 pad;     // explicitly initialize this to appease valgrind
 237 #endif
 238   };
 239 #pragma pack(pop)
 240
 241   Header* header() {
 242     return headerT<Header>();
 243   }
 244   const Header* header() const {
 245     return headerT<Header>();
 246   }
 247
 248   void Init();
 249
 250   // Used internally to support IPC::Listener::OnBadMessageReceived.
 251   mutable bool dispatch_error_;
 252
 253 #if defined(OS_POSIX)
 254   // The set of file descriptors associated with this message.
 255   scoped_refptr<FileDescriptorSet> file_descriptor_set_;
 256
 257   // Ensure that a FileDescriptorSet is allocated
 258   void EnsureFileDescriptorSet();
 259
 260   FileDescriptorSet* file_descriptor_set() {
 261     EnsureFileDescriptorSet();
 262     return file_descriptor_set_.get();
 263   }
 264   const FileDescriptorSet* file_descriptor_set() const {
 265     return file_descriptor_set_.get();
 266   }
 267 #endif
 268
 269 #ifdef IPC_MESSAGE_LOG_ENABLED
 270   // Used for logging.
 271   mutable int64 received_time_;
 272   mutable std::string output_params_;
 273   mutable LogData* log_data_;
 274   mutable bool dont_log_;
 275 #endif
 276 };
 277
 278 //------------------------------------------------------------------------------
 279
 280 }  // namespace IPC
 281
 282 enum SpecialRoutingIDs {
 283   // indicates that we don't have a routing ID yet.
 284   MSG_ROUTING_NONE = -2,
 285
 286   // indicates a general message not sent to a particular tab.
 287   MSG_ROUTING_CONTROL = kint32max,
 288 };
 289
 290 #define IPC_REPLY_ID 0xFFFFFFF0  // Special message id for replies
 291 #define IPC_LOGGING_ID 0xFFFFFFF1  // Special message id for logging
 292
 293 #endif  // IPC_IPC_MESSAGE_H_