cc/surfaces/surface_sequence.h

   1 // Copyright 2014 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 CC_SURFACES_SURFACE_SEQUENCE_H_
   6 #define CC_SURFACES_SURFACE_SEQUENCE_H_
   7
   8 #include "base/containers/hash_tables.h"
   9
  10 namespace cc {
  11
  12 // A per-surface-namespace sequence number that's used to coordinate
  13 // dependencies between frames. A sequence number may be satisfied once, and
  14 // may be depended on once.
  15 struct SurfaceSequence {
  16   SurfaceSequence() : id_namespace(0u), sequence(0u) {}
  17   SurfaceSequence(uint32_t id_namespace, uint32_t sequence)
  18       : id_namespace(id_namespace), sequence(sequence) {}
  19   bool is_null() const { return id_namespace == 0u && sequence == 0u; }
  20
  21   uint32_t id_namespace;
  22   uint32_t sequence;
  23 };
  24
  25 inline bool operator==(const SurfaceSequence& a, const SurfaceSequence& b) {
  26   return a.id_namespace == b.id_namespace && a.sequence == b.sequence;
  27 }
  28
  29 inline bool operator!=(const SurfaceSequence& a, const SurfaceSequence& b) {
  30   return !(a == b);
  31 }
  32
  33 inline bool operator<(const SurfaceSequence& a, const SurfaceSequence& b) {
  34   if (a.id_namespace != b.id_namespace)
  35     return a.id_namespace < b.id_namespace;
  36   return a.sequence < b.sequence;
  37 }
  38
  39 }  // namespace cc
  40
  41 namespace BASE_HASH_NAMESPACE {
  42 template <>
  43 struct hash<cc::SurfaceSequence> {
  44   size_t operator()(cc::SurfaceSequence key) const {
  45     return base::HashPair(key.id_namespace, key.sequence);
  46   }
  47 };
  48 }  // namespace BASE_HASH_NAMESPACE
  49
  50 #endif  // CC_SURFACES_SURFACE_SEQUENCE_H_