// Copyright (c) 2011 The Chromium Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #ifndef IPC_IPC_MESSAGE_ATTACHMENT_SET_H_ #define IPC_IPC_MESSAGE_ATTACHMENT_SET_H_ #include #include #include "base/memory/ref_counted.h" #include "build/build_config.h" #include "ipc/ipc_message_support_export.h" namespace IPC { class MessageAttachment; // ----------------------------------------------------------------------------- // A MessageAttachmentSet is an ordered set of MessageAttachment objects // associated with an IPC message. All attachments are wrapped in a mojo handle // if necessary and sent over the mojo message pipe. // // For ChannelNacl under SFI NaCl, only Type::PLATFORM_FILE is supported. In // that case, the FD is sent over socket. // ----------------------------------------------------------------------------- class IPC_MESSAGE_SUPPORT_EXPORT MessageAttachmentSet : public base::RefCountedThreadSafe { public: MessageAttachmentSet(); MessageAttachmentSet(const MessageAttachmentSet&) = delete; MessageAttachmentSet& operator=(const MessageAttachmentSet&) = delete; // Return the number of attachments unsigned size() const; // Return true if no unconsumed descriptors remain bool empty() const { return attachments_.empty(); } // Returns whether the attachment was successfully added. // |index| is an output variable. On success, it contains the index of the // newly added attachment. bool AddAttachment(scoped_refptr attachment, size_t* index); // Similar to the above method, but without output variables. bool AddAttachment(scoped_refptr attachment); // Take the nth from the beginning of the vector, Code using this /must/ // access the attachments in order, and must do it at most once. // // This interface is designed for the deserialising code as it doesn't // support close flags. // returns: an attachment, or nullptr on error scoped_refptr GetAttachmentAt(unsigned index); // Marks all the descriptors as consumed and closes those which are // auto-close. void CommitAllDescriptors(); #if BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA) // This is the maximum number of descriptors per message. We need to know this // because the control message kernel interface has to be given a buffer which // is large enough to store all the descriptor numbers. Otherwise the kernel // tells us that it truncated the control data and the extra descriptors are // lost. // // In debugging mode, it's a fatal error to try and add more than this number // of descriptors to a MessageAttachmentSet. static const size_t kMaxDescriptorsPerMessage = 7; #endif // BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA) // --------------------------------------------------------------------------- private: friend class base::RefCountedThreadSafe; ~MessageAttachmentSet(); // Return the number of file descriptors unsigned num_descriptors() const; std::vector> attachments_; // This contains the index of the next descriptor which should be consumed. // It's used in a couple of ways. Firstly, at destruction we can check that // all the descriptors have been read (with GetNthDescriptor). Secondly, we // can check that they are read in order. unsigned consumed_descriptor_highwater_; }; } // namespace IPC #endif // IPC_IPC_MESSAGE_ATTACHMENT_SET_H_