tools/clang/blink_gc_plugin/NeedsTracing.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 // NeedsTracing is a three-point value ordered by unneeded < unknown < needed.
   6 // Unneeded means that the point definitively does not need to be traced.
   7
   8 #ifndef TOOLS_BLINK_GC_PLUGIN_NEEDS_TRACING_H_
   9 #define TOOLS_BLINK_GC_PLUGIN_NEEDS_TRACING_H_
  10
  11 class NeedsTracing {
  12  public:
  13   static NeedsTracing Unneeded() { return kUnneeded; }
  14   static NeedsTracing Unknown() { return kUnknown; }
  15   static NeedsTracing Needed() { return kNeeded; }
  16   bool IsUnneeded() { return value_ == kUnneeded; }
  17   bool IsUnknown() { return value_ == kUnknown; }
  18   bool IsNeeded() { return value_ == kNeeded; }
  19   NeedsTracing LUB(const NeedsTracing& other) {
  20     return value_ > other.value_ ? value_ : other.value_;
  21   }
  22   bool operator==(const NeedsTracing& other) {
  23     return value_ == other.value_;
  24   }
  25  private:
  26   enum Value { kUnneeded, kUnknown, kNeeded };
  27   NeedsTracing(Value value) : value_(value) {}
  28   Value value_;
  29 };
  30
  31 #endif // TOOLS_BLINK_GC_PLUGIN_NEEDS_TRACING_H_