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// 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.
#include <stddef.h>
#include <vector>
#include "base/macros.h"
#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<MessageAttachmentSet> {
// 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<MessageAttachment> attachment,
size_t* index);
// Similar to the above method, but without output variables.
bool AddAttachment(scoped_refptr<MessageAttachment> 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<MessageAttachment> GetAttachmentAt(unsigned index);
// Marks all the descriptors as consumed and closes those which are
// auto-close.
void CommitAllDescriptors();
#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;
#endif // OS_POSIX
// ---------------------------------------------------------------------------
friend class base::RefCountedThreadSafe<MessageAttachmentSet>;
// Return the number of file descriptors
unsigned num_descriptors() const;
std::vector<scoped_refptr<MessageAttachment>> 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