| // 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 <stddef.h> |
| |
| #include <vector> |
| |
| #include "base/macros.h" |
| #include "base/memory/ref_counted.h" |
| #include "build/build_config.h" |
| #include "ipc/ipc_export.h" |
| |
| #if defined(OS_POSIX) |
| #include "base/files/file.h" |
| #endif |
| |
| namespace IPC { |
| |
| class BrokerableAttachment; |
| class MessageAttachment; |
| |
| // ----------------------------------------------------------------------------- |
| // A MessageAttachmentSet is an ordered set of MessageAttachment objects |
| // associated with an IPC message. There are three types of MessageAttachments: |
| // 1) TYPE_PLATFORM_FILE is transmitted over the Channel's underlying |
| // UNIX domain socket |
| // 2) TYPE_MOJO_HANDLE is transmitted over the Mojo MessagePipe. |
| // 3) TYPE_BROKERABLE_ATTACHMENT is transmitted by the Attachment Broker. |
| // Any given IPC Message can have attachments of type (1) or (2), but not both. |
| // These are stored in |attachments_|. Attachments of type (3) are stored in |
| // |brokerable_attachments_|. |
| // |
| // To produce a deterministic ordering, all attachments in |attachments_| are |
| // considered to come before those in |brokerable_attachments_|. These |
| // attachments are transmitted across different communication channels, and |
| // multiplexed by the receiver, so ordering between them cannot be guaranteed. |
| // |
| // ----------------------------------------------------------------------------- |
| class IPC_EXPORT MessageAttachmentSet |
| : public base::RefCountedThreadSafe<MessageAttachmentSet> { |
| public: |
| MessageAttachmentSet(); |
| |
| // Return the number of attachments |
| unsigned size() const; |
| // Return the number of file descriptors |
| unsigned num_descriptors() const; |
| // Return the number of mojo handles in the attachment set |
| unsigned num_mojo_handles() const; |
| // Return the number of brokerable attachments in the attachment set. |
| unsigned num_brokerable_attachments() const; |
| // Return the number of non-brokerable attachments in the attachment set. |
| unsigned num_non_brokerable_attachments() const; |
| |
| // Return true if no unconsumed descriptors remain |
| bool empty() const { return 0 == size(); } |
| |
| // Returns whether the attachment was successfully added. |
| // |index| is an output variable. On success, it contains the index of the |
| // newly added attachment. |
| // |brokerable| is an output variable. On success, it describes which vector |
| // the attachment was added to. |
| bool AddAttachment(scoped_refptr<MessageAttachment> attachment, |
| size_t* index, |
| bool* brokerable); |
| |
| // Similar to the above method, but without output variables. |
| bool AddAttachment(scoped_refptr<MessageAttachment> attachment); |
| |
| // Take the nth non-brokerable attachment 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<MessageAttachment> GetNonBrokerableAttachmentAt(unsigned index); |
| |
| // Similar to GetNonBrokerableAttachmentAt, but there are no ordering |
| // requirements. |
| scoped_refptr<MessageAttachment> GetBrokerableAttachmentAt(unsigned index); |
| |
| // This must be called after transmitting the descriptors returned by |
| // PeekDescriptors. It marks all the non-brokerable descriptors as consumed |
| // and closes those which are auto-close. |
| void CommitAllDescriptors(); |
| |
| // Returns a vector of all brokerable attachments. |
| std::vector<scoped_refptr<IPC::BrokerableAttachment>> |
| GetBrokerableAttachments() const; |
| |
| // Replaces a placeholder brokerable attachment with |attachment|, matching |
| // them by their id. |
| void ReplacePlaceholderWithAttachment( |
| const scoped_refptr<BrokerableAttachment>& attachment); |
| |
| #if defined(OS_POSIX) |
| // 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; |
| |
| // --------------------------------------------------------------------------- |
| // Interfaces for transmission... |
| |
| // Fill an array with file descriptors without 'consuming' them. |
| // CommitAllDescriptors must be called after these descriptors have been |
| // transmitted. |
| // buffer: (output) a buffer of, at least, size() integers. |
| void PeekDescriptors(base::PlatformFile* buffer) const; |
| // Returns true if any contained file descriptors appear to be handles to a |
| // directory. |
| bool ContainsDirectoryDescriptor() const; |
| // Fetch all filedescriptors with the "auto close" property. Used instead of |
| // CommitAllDescriptors() when closing must be handled manually. |
| void ReleaseFDsToClose(std::vector<base::PlatformFile>* fds); |
| |
| // --------------------------------------------------------------------------- |
| |
| // --------------------------------------------------------------------------- |
| // Interfaces for receiving... |
| |
| // Set the contents of the set from the given buffer. This set must be empty |
| // before calling. The auto-close flag is set on all the descriptors so that |
| // unconsumed descriptors are closed on destruction. |
| void AddDescriptorsToOwn(const base::PlatformFile* buffer, unsigned count); |
| |
| #endif // OS_POSIX |
| |
| // --------------------------------------------------------------------------- |
| |
| private: |
| friend class base::RefCountedThreadSafe<MessageAttachmentSet>; |
| |
| ~MessageAttachmentSet(); |
| |
| // All elements either have type TYPE_PLATFORM_FILE or TYPE_MOJO_HANDLE. |
| std::vector<scoped_refptr<MessageAttachment>> attachments_; |
| |
| // All elements have type TYPE_BROKERABLE_ATTACHMENT. |
| std::vector<scoped_refptr<BrokerableAttachment>> brokerable_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. |
| mutable unsigned consumed_descriptor_highwater_; |
| |
| DISALLOW_COPY_AND_ASSIGN(MessageAttachmentSet); |
| }; |
| |
| } // namespace IPC |
| |
| #endif // IPC_IPC_MESSAGE_ATTACHMENT_SET_H_ |