ipc/brokerable_attachment.h

   1 // Copyright 2015 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_BROKERABLE_ATTACHMENT_H_
   6 #define IPC_BROKERABLE_ATTACHMENT_H_
   7
   8 #include <stdint.h>
   9
  10 #include "base/macros.h"
  11 #include "ipc/ipc_export.h"
  12 #include "ipc/ipc_message_attachment.h"
  13
  14 namespace IPC {
  15
  16 // This subclass of MessageAttachment requires an AttachmentBroker to be
  17 // attached to a Chrome IPC message.
  18 class IPC_EXPORT BrokerableAttachment : public MessageAttachment {
  19  public:
  20   static const size_t kNonceSize = 16;
  21   // An id uniquely identifies an attachment sent via a broker.
  22   struct IPC_EXPORT AttachmentId {
  23     uint8_t nonce[kNonceSize];
  24
  25     // Default constructor returns an unguessable random nonce.
  26     AttachmentId();
  27
  28     // Constructs an AttachmentId from a buffer.
  29     AttachmentId(const char* start_address, size_t size);
  30
  31     // Writes the nonce into a buffer.
  32     void SerializeToBuffer(char* start_address, size_t size);
  33
  34     bool operator==(const AttachmentId& rhs) const {
  35       for (size_t i = 0; i < kNonceSize; ++i) {
  36         if (nonce[i] != rhs.nonce[i])
  37           return false;
  38       }
  39       return true;
  40     }
  41
  42     bool operator<(const AttachmentId& rhs) const {
  43       for (size_t i = 0; i < kNonceSize; ++i) {
  44         if (nonce[i] < rhs.nonce[i])
  45           return true;
  46         if (nonce[i] > rhs.nonce[i])
  47           return false;
  48       }
  49       return false;
  50     }
  51   };
  52
  53   enum BrokerableType {
  54     WIN_HANDLE,
  55   };
  56
  57   // The identifier is unique across all Chrome processes.
  58   AttachmentId GetIdentifier() const;
  59
  60   // Whether the attachment still needs information from the broker before it
  61   // can be used.
  62   bool NeedsBrokering() const;
  63
  64   // Fills in the data of this instance with the data from |attachment|.
  65   // This instance must require brokering, |attachment| must be brokered, and
  66   // both instances must have the same identifier.
  67   virtual void PopulateWithAttachment(
  68       const BrokerableAttachment* attachment) = 0;
  69
  70   // Returns TYPE_BROKERABLE_ATTACHMENT
  71   Type GetType() const override;
  72
  73   virtual BrokerableType GetBrokerableType() const = 0;
  74
  75  protected:
  76   BrokerableAttachment();
  77   BrokerableAttachment(const AttachmentId& id, bool needs_brokering);
  78   ~BrokerableAttachment() override;
  79
  80   void SetNeedsBrokering(bool needs_brokering);
  81
  82  private:
  83   // This member uniquely identifies a BrokerableAttachment across all Chrome
  84   // processes.
  85   const AttachmentId id_;
  86
  87   // Whether the attachment still needs to be filled in by an AttachmentBroker.
  88   bool needs_brokering_;
  89   DISALLOW_COPY_AND_ASSIGN(BrokerableAttachment);
  90 };
  91
  92 }  // namespace IPC
  93
  94 #endif  // IPC_BROKERABLE_ATTACHMENT_H_