tools/gn/label_ptr.h

   1 // Copyright (c) 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 TOOLS_GN_LABEL_PTR_H_
   6 #define TOOLS_GN_LABEL_PTR_H_
   7
   8 #include <functional>
   9
  10 class ParseNode;
  11
  12 // Structure that holds a labeled "thing". This is used for various places
  13 // where we need to store lists of targets or configs. We sometimes populate
  14 // the pointers on another thread from where we compute the labels, so this
  15 // structure lets us save them separately. This also allows us to store the
  16 // location of the thing that added this dependency.
  17 template<typename T>
  18 struct LabelPtrPair {
  19   typedef T DestType;
  20
  21   LabelPtrPair() : label(), ptr(NULL), origin(NULL) {}
  22
  23   // This contructor is typically used in unit tests, it extracts the label
  24   // automatically from a given pointer.
  25   explicit LabelPtrPair(const T* p) : label(p->label()), ptr(p), origin(NULL) {
  26   }
  27
  28   ~LabelPtrPair() {}
  29
  30   Label label;
  31   const T* ptr;  // May be NULL.
  32   const ParseNode* origin;  // May be NULL.
  33 };
  34
  35 typedef LabelPtrPair<Config> LabelConfigPair;
  36 typedef LabelPtrPair<Target> LabelTargetPair;
  37
  38 typedef std::vector<LabelConfigPair> LabelConfigVector;
  39 typedef std::vector<LabelTargetPair> LabelTargetVector;
  40
  41 // Comparison and search functions ---------------------------------------------
  42
  43 // To do a brute-force search by label:
  44 // std::find_if(vect.begin(), vect.end(), LabelPtrLabelEquals<Config>(label));
  45 template<typename T>
  46 struct LabelPtrLabelEquals : public std::unary_function<Label, bool> {
  47   explicit LabelPtrLabelEquals(const Label& l) : label(l) {}
  48
  49   bool operator()(const LabelPtrPair<T>& arg) const {
  50     return arg.label == label;
  51   }
  52
  53   const Label& label;
  54 };
  55
  56 // To do a brute-force search by object pointer:
  57 // std::find_if(vect.begin(), vect.end(), LabelPtrLabelEquals<Config>(config));
  58 template<typename T>
  59 struct LabelPtrPtrEquals : public std::unary_function<T, bool> {
  60   explicit LabelPtrPtrEquals(const T* p) : ptr(p) {}
  61
  62   bool operator()(const LabelPtrPair<T>& arg) const {
  63     return arg.ptr == ptr;
  64   }
  65
  66   const T* ptr;
  67 };
  68
  69 // To sort by label:
  70 // std::sort(vect.begin(), vect.end(), LabelPtrLabelLess<Config>());
  71 template<typename T>
  72 struct LabelPtrLabelLess : public std::binary_function<LabelPtrPair<T>,
  73                                                        LabelPtrPair<T>,
  74                                                        bool> {
  75   bool operator()(const LabelPtrPair<T>& a, const LabelPtrPair<T>& b) const {
  76     return a.label < b.label;
  77   }
  78 };
  79
  80 #endif  // TOOLS_GN_LABEL_PTR_H_