mojo/system/constants.h

   1 // Copyright 2013 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 MOJO_SYSTEM_CONSTANTS_H_
   6 #define MOJO_SYSTEM_CONSTANTS_H_
   7
   8 #include <stddef.h>
   9
  10 namespace mojo {
  11 namespace system {
  12
  13 // Maximum number of open (Mojo) handles.
  14 // TODO(vtl): This doesn't count "live" handles, some of which may live in
  15 // messages.
  16 const size_t kMaxHandleTableSize = 1000000;
  17
  18 // Maximum number of active memory mappings.
  19 const size_t kMaxMappingTableSize = 1000000;
  20
  21 const size_t kMaxWaitManyNumHandles = kMaxHandleTableSize;
  22
  23 const size_t kMaxMessageNumBytes = 4 * 1024 * 1024;
  24
  25 const size_t kMaxMessageNumHandles = 10000;
  26
  27 // Maximum capacity of a data pipe, in bytes. This value must fit into a
  28 // |uint32_t|.
  29 // WARNING: If you bump it closer to 2^32, you must audit all the code to check
  30 // that we don't overflow (2^31 would definitely be risky; up to 2^30 is
  31 // probably okay).
  32 const size_t kMaxDataPipeCapacityBytes = 256 * 1024 * 1024;  // 256 MB.
  33
  34 const size_t kDefaultDataPipeCapacityBytes = 1024 * 1024;  // 1 MB.
  35
  36 // Alignment for the "start" of the data buffer used by data pipes. (The
  37 // alignment of elements will depend on this and the element size.)
  38 const size_t kDataPipeBufferAlignmentBytes = 16;
  39
  40 // TODO(vtl): Set this hard limit appropriately (e.g., higher on 64-bit). (This
  41 // will also entail some auditing to make sure I'm not messing up my checks
  42 // anywhere.)
  43 const size_t kMaxSharedMemoryNumBytes = 1024 * 1024 * 1024;  // 1 GB.
  44
  45 }  // namespace system
  46 }  // namespace mojo
  47
  48 #endif  // MOJO_SYSTEM_CONSTANTS_H_