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