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