1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/ipc/chromium/src/chrome/common/file_descriptor_set_posix.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,108 @@
1.4 +// Copyright (c) 2006-2009 The Chromium Authors. All rights reserved.
1.5 +// Use of this source code is governed by a BSD-style license that can be
1.6 +// found in the LICENSE file.
1.7 +
1.8 +#ifndef CHROME_COMMON_FILE_DESCRIPTOR_SET_POSIX_H_
1.9 +#define CHROME_COMMON_FILE_DESCRIPTOR_SET_POSIX_H_
1.10 +
1.11 +#include <vector>
1.12 +
1.13 +#include "base/basictypes.h"
1.14 +#include "base/file_descriptor_posix.h"
1.15 +#include "base/ref_counted.h"
1.16 +
1.17 +// -----------------------------------------------------------------------------
1.18 +// A FileDescriptorSet is an ordered set of POSIX file descriptors. These are
1.19 +// associated with IPC messages so that descriptors can be transmitted over a
1.20 +// UNIX domain socket.
1.21 +// -----------------------------------------------------------------------------
1.22 +class FileDescriptorSet : public base::RefCountedThreadSafe<FileDescriptorSet> {
1.23 + public:
1.24 + FileDescriptorSet();
1.25 + ~FileDescriptorSet();
1.26 +
1.27 + // This is the maximum number of descriptors per message. We need to know this
1.28 + // because the control message kernel interface has to be given a buffer which
1.29 + // is large enough to store all the descriptor numbers. Otherwise the kernel
1.30 + // tells us that it truncated the control data and the extra descriptors are
1.31 + // lost.
1.32 + //
1.33 + // In debugging mode, it's a fatal error to try and add more than this number
1.34 + // of descriptors to a FileDescriptorSet.
1.35 + enum {
1.36 + MAX_DESCRIPTORS_PER_MESSAGE = 4
1.37 + };
1.38 +
1.39 + // ---------------------------------------------------------------------------
1.40 + // Interfaces for building during message serialisation...
1.41 +
1.42 + // Add a descriptor to the end of the set. Returns false iff the set is full.
1.43 + bool Add(int fd);
1.44 + // Add a descriptor to the end of the set and automatically close it after
1.45 + // transmission. Returns false iff the set is full.
1.46 + bool AddAndAutoClose(int fd);
1.47 +
1.48 + // ---------------------------------------------------------------------------
1.49 +
1.50 +
1.51 + // ---------------------------------------------------------------------------
1.52 + // Interfaces for accessing during message deserialisation...
1.53 +
1.54 + // Return the number of descriptors
1.55 + unsigned size() const { return descriptors_.size(); }
1.56 + // Return true if no unconsumed descriptors remain
1.57 + bool empty() const { return descriptors_.empty(); }
1.58 + // Fetch the nth descriptor from the beginning of the set. Code using this
1.59 + // /must/ access the descriptors in order, except that it may wrap from the
1.60 + // end to index 0 again.
1.61 + //
1.62 + // This interface is designed for the deserialising code as it doesn't
1.63 + // support close flags.
1.64 + // returns: file descriptor, or -1 on error
1.65 + int GetDescriptorAt(unsigned n) const;
1.66 +
1.67 + // ---------------------------------------------------------------------------
1.68 +
1.69 +
1.70 + // ---------------------------------------------------------------------------
1.71 + // Interfaces for transmission...
1.72 +
1.73 + // Fill an array with file descriptors without 'consuming' them. CommitAll
1.74 + // must be called after these descriptors have been transmitted.
1.75 + // buffer: (output) a buffer of, at least, size() integers.
1.76 + void GetDescriptors(int* buffer) const;
1.77 + // This must be called after transmitting the descriptors returned by
1.78 + // GetDescriptors. It marks all the descriptors as consumed and closes those
1.79 + // which are auto-close.
1.80 + void CommitAll();
1.81 +
1.82 + // ---------------------------------------------------------------------------
1.83 +
1.84 +
1.85 + // ---------------------------------------------------------------------------
1.86 + // Interfaces for receiving...
1.87 +
1.88 + // Set the contents of the set from the given buffer. This set must be empty
1.89 + // before calling. The auto-close flag is set on all the descriptors so that
1.90 + // unconsumed descriptors are closed on destruction.
1.91 + void SetDescriptors(const int* buffer, unsigned count);
1.92 +
1.93 + // ---------------------------------------------------------------------------
1.94 +
1.95 + private:
1.96 + // A vector of descriptors and close flags. If this message is sent, then
1.97 + // these descriptors are sent as control data. After sending, any descriptors
1.98 + // with a true flag are closed. If this message has been received, then these
1.99 + // are the descriptors which were received and all close flags are true.
1.100 + std::vector<base::FileDescriptor> descriptors_;
1.101 +
1.102 + // This contains the index of the next descriptor which should be consumed.
1.103 + // It's used in a couple of ways. Firstly, at destruction we can check that
1.104 + // all the descriptors have been read (with GetNthDescriptor). Secondly, we
1.105 + // can check that they are read in order.
1.106 + mutable unsigned consumed_descriptor_highwater_;
1.107 +
1.108 + DISALLOW_COPY_AND_ASSIGN(FileDescriptorSet);
1.109 +};
1.110 +
1.111 +#endif // CHROME_COMMON_FILE_DESCRIPTOR_SET_POSIX_H_
