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 #pragma once
   8
   9 #include <string>
  10
  11 #include "base/basictypes.h"
  12 #include "base/pickle.h"
  13 #include "ipc/ipc_export.h"
  14
  15 // Ipc logging adds a dependency from the 'chrome' target on all ipc message
  16 // classes. In a component build, this would require exporting all message
  17 // classes, so don't support ipc logging in the components build.
  18 #if !defined(NDEBUG) && !defined(COMPONENT_BUILD)
  19 #define IPC_MESSAGE_LOG_ENABLED
  20 #endif
  21
  22 #if defined(OS_POSIX)
  23 #include "base/memory/ref_counted.h"
  24 #endif
  25
  26 namespace base {
  27 struct FileDescriptor;
  28 }
  29
  30 class FileDescriptorSet;
  31
  32 namespace IPC {
  33
  34 //------------------------------------------------------------------------------
  35
  36 class Channel;
  37 class Message;
  38 struct LogData;
  39
  40 class IPC_EXPORT Message : public Pickle {
  41  public:
  42   // Implemented by objects that can send IPC messages across a channel.
  43   class IPC_EXPORT Sender {
  44    public:
  45     virtual ~Sender() {}
  46
  47     // Sends the given IPC message.  The implementor takes ownership of the
  48     // given Message regardless of whether or not this method succeeds.  This
  49     // is done to make this method easier to use.  Returns true on success and
  50     // false otherwise.
  51     virtual bool Send(Message* msg) = 0;
  52   };
  53
  54   enum PriorityValue {
  55     PRIORITY_LOW = 1,
  56     PRIORITY_NORMAL,
  57     PRIORITY_HIGH
  58   };
  59
  60   virtual ~Message();
  61
  62   Message();
  63
  64   // Initialize a message with a user-defined type, priority value, and
  65   // destination WebView ID.
  66   Message(int32 routing_id, uint32 type, PriorityValue priority);
  67
  68   // Initializes a message from a const block of data.  The data is not copied;
  69   // instead the data is merely referenced by this message.  Only const methods
  70   // should be used on the message when initialized this way.
  71   Message(const char* data, int data_len);
  72
  73   Message(const Message& other);
  74   Message& operator=(const Message& other);
  75
  76   PriorityValue priority() const {
  77     return static_cast<PriorityValue>(header()->flags & PRIORITY_MASK);
  78   }
  79
  80   // True if this is a synchronous message.
  81   bool is_sync() const {
  82     return (header()->flags & SYNC_BIT) != 0;
  83   }
  84
  85   // Set this on a reply to a synchronous message.
  86   void set_reply() {
  87     header()->flags |= REPLY_BIT;
  88   }
  89
  90   bool is_reply() const {
  91     return (header()->flags & REPLY_BIT) != 0;
  92   }
  93
  94   // Set this on a reply to a synchronous message to indicate that no receiver
  95   // was found.
  96   void set_reply_error() {
  97     header()->flags |= REPLY_ERROR_BIT;
  98   }
  99
 100   bool is_reply_error() const {
 101     return (header()->flags & REPLY_ERROR_BIT) != 0;
 102   }
 103
 104   // Normally when a receiver gets a message and they're blocked on a
 105   // synchronous message Send, they buffer a message.  Setting this flag causes
 106   // the receiver to be unblocked and the message to be dispatched immediately.
 107   void set_unblock(bool unblock) {
 108     if (unblock) {
 109       header()->flags |= UNBLOCK_BIT;
 110     } else {
 111       header()->flags &= ~UNBLOCK_BIT;
 112     }
 113   }
 114
 115   bool should_unblock() const {
 116     return (header()->flags & UNBLOCK_BIT) != 0;
 117   }
 118
 119   // Tells the receiver that the caller is pumping messages while waiting
 120   // for the result.
 121   bool is_caller_pumping_messages() const {
 122     return (header()->flags & PUMPING_MSGS_BIT) != 0;
 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   template<class T, class S>
 138   static bool Dispatch(const Message* msg, T* obj, S* sender,
 139                        void (T::*func)()) {
 140     (obj->*func)();
 141     return true;
 142   }
 143
 144   template<class T, class S>
 145   static bool Dispatch(const Message* msg, T* obj, S* sender,
 146                        void (T::*func)() const) {
 147     (obj->*func)();
 148     return true;
 149   }
 150
 151   template<class T, class S>
 152   static bool Dispatch(const Message* msg, T* obj, S* sender,
 153                        void (T::*func)(const Message&)) {
 154     (obj->*func)(*msg);
 155     return true;
 156   }
 157
 158   template<class T, class S>
 159   static bool Dispatch(const Message* msg, T* obj, S* sender,
 160                        void (T::*func)(const Message&) const) {
 161     (obj->*func)(*msg);
 162     return true;
 163   }
 164
 165   // Used for async messages with no parameters.
 166   static void Log(std::string* name, const Message* msg, std::string* l) {
 167   }
 168
 169   // Find the end of the message data that starts at range_start.  Returns NULL
 170   // if the entire message is not found in the given data range.
 171   static const char* FindNext(const char* range_start, const char* range_end) {
 172     return Pickle::FindNext(sizeof(Header), range_start, range_end);
 173   }
 174
 175 #if defined(OS_POSIX)
 176   // On POSIX, a message supports reading / writing FileDescriptor objects.
 177   // This is used to pass a file descriptor to the peer of an IPC channel.
 178
 179   // Add a descriptor to the end of the set. Returns false iff the set is full.
 180   bool WriteFileDescriptor(const base::FileDescriptor& descriptor);
 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 ReadFileDescriptor(PickleIterator* iter,
 184                           base::FileDescriptor* descriptor) const;
 185 #endif
 186
 187 #ifdef IPC_MESSAGE_LOG_ENABLED
 188   // Adds the outgoing time from Time::Now() at the end of the message and sets
 189   // a bit to indicate that it's been added.
 190   void set_sent_time(int64 time);
 191   int64 sent_time() const;
 192
 193   void set_received_time(int64 time) const;
 194   int64 received_time() const { return received_time_; }
 195   void set_output_params(const std::string& op) const { output_params_ = op; }
 196   const std::string& output_params() const { return output_params_; }
 197   // The following four functions are needed so we can log sync messages with
 198   // delayed replies.  We stick the log data from the sent message into the
 199   // reply message, so that when it's sent and we have the output parameters
 200   // we can log it.  As such, we set a flag on the sent message to not log it.
 201   void set_sync_log_data(LogData* data) const { log_data_ = data; }
 202   LogData* sync_log_data() const { return log_data_; }
 203   void set_dont_log() const { dont_log_ = true; }
 204   bool dont_log() const { return dont_log_; }
 205 #endif
 206
 207  protected:
 208   friend class Channel;
 209   friend class MessageReplyDeserializer;
 210   friend class SyncMessage;
 211
 212   void set_sync() {
 213     header()->flags |= SYNC_BIT;
 214   }
 215
 216   // flags
 217   enum {
 218     PRIORITY_MASK   = 0x0003,
 219     SYNC_BIT        = 0x0004,
 220     REPLY_BIT       = 0x0008,
 221     REPLY_ERROR_BIT = 0x0010,
 222     UNBLOCK_BIT     = 0x0020,
 223     PUMPING_MSGS_BIT= 0x0040,
 224     HAS_SENT_TIME_BIT = 0x0080,
 225   };
 226
 227 #pragma pack(push, 4)
 228   struct Header : Pickle::Header {
 229     int32 routing;  // ID of the view that this message is destined for
 230     uint32 type;    // specifies the user-defined message type
 231     uint32 flags;   // specifies control flags for the message
 232 #if defined(OS_POSIX)
 233     uint16 num_fds; // the number of descriptors included with this message
 234     uint16 pad;     // explicitly initialize this to appease valgrind
 235 #endif
 236   };
 237 #pragma pack(pop)
 238
 239   Header* header() {
 240     return headerT<Header>();
 241   }
 242   const Header* header() const {
 243     return headerT<Header>();
 244   }
 245
 246   void InitLoggingVariables();
 247
 248 #if defined(OS_POSIX)
 249   // The set of file descriptors associated with this message.
 250   scoped_refptr<FileDescriptorSet> file_descriptor_set_;
 251
 252   // Ensure that a FileDescriptorSet is allocated
 253   void EnsureFileDescriptorSet();
 254
 255   FileDescriptorSet* file_descriptor_set() {
 256     EnsureFileDescriptorSet();
 257     return file_descriptor_set_.get();
 258   }
 259   const FileDescriptorSet* file_descriptor_set() const {
 260     return file_descriptor_set_.get();
 261   }
 262 #endif
 263
 264 #ifdef IPC_MESSAGE_LOG_ENABLED
 265   // Used for logging.
 266   mutable int64 received_time_;
 267   mutable std::string output_params_;
 268   mutable LogData* log_data_;
 269   mutable bool dont_log_;
 270 #endif
 271 };
 272
 273 //------------------------------------------------------------------------------
 274
 275 }  // namespace IPC
 276
 277 enum SpecialRoutingIDs {
 278   // indicates that we don't have a routing ID yet.
 279   MSG_ROUTING_NONE = -2,
 280
 281   // indicates a general message not sent to a particular tab.
 282   MSG_ROUTING_CONTROL = kint32max,
 283 };
 284
 285 #define IPC_REPLY_ID 0xFFFFFFF0  // Special message id for replies
 286 #define IPC_LOGGING_ID 0xFFFFFFF1  // Special message id for logging
 287
 288 #endif  // IPC_IPC_MESSAGE_H_