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 #include "tools/gn/label.h"
  11
  12 class Config;
  13 class ParseNode;
  14 class Target;
  15
  16 // Structure that holds a labeled "thing". This is used for various places
  17 // where we need to store lists of targets or configs. We sometimes populate
  18 // the pointers on another thread from where we compute the labels, so this
  19 // structure lets us save them separately. This also allows us to store the
  20 // location of the thing that added this dependency.
  21 template<typename T>
  22 struct LabelPtrPair {
  23   typedef T DestType;
  24
  25   LabelPtrPair() : label(), ptr(NULL), origin(NULL) {}
  26
  27   explicit LabelPtrPair(const Label& l) : label(l), ptr(NULL), origin(NULL) {
  28   }
  29
  30   // This contructor is typically used in unit tests, it extracts the label
  31   // automatically from a given pointer.
  32   explicit LabelPtrPair(const T* p) : label(p->label()), ptr(p), origin(NULL) {
  33   }
  34
  35   ~LabelPtrPair() {}
  36
  37   Label label;
  38   const T* ptr;  // May be NULL.
  39
  40   // The origin of this dependency. This will be null for internally generated
  41   // dependencies. This happens when a group is automatically expanded and that
  42   // group's members are added to the target that depends on that group.
  43   const ParseNode* origin;
  44 };
  45
  46 typedef LabelPtrPair<Config> LabelConfigPair;
  47 typedef LabelPtrPair<Target> LabelTargetPair;
  48
  49 typedef std::vector<LabelConfigPair> LabelConfigVector;
  50 typedef std::vector<LabelTargetPair> LabelTargetVector;
  51
  52 // Comparison and search functions ---------------------------------------------
  53
  54 // To do a brute-force search by label:
  55 // std::find_if(vect.begin(), vect.end(), LabelPtrLabelEquals<Config>(label));
  56 template<typename T>
  57 struct LabelPtrLabelEquals : public std::unary_function<Label, bool> {
  58   explicit LabelPtrLabelEquals(const Label& l) : label(l) {}
  59
  60   bool operator()(const LabelPtrPair<T>& arg) const {
  61     return arg.label == label;
  62   }
  63
  64   const Label& label;
  65 };
  66
  67 // To do a brute-force search by object pointer:
  68 // std::find_if(vect.begin(), vect.end(), LabelPtrPtrEquals<Config>(config));
  69 template<typename T>
  70 struct LabelPtrPtrEquals : public std::unary_function<T, bool> {
  71   explicit LabelPtrPtrEquals(const T* p) : ptr(p) {}
  72
  73   bool operator()(const LabelPtrPair<T>& arg) const {
  74     return arg.ptr == ptr;
  75   }
  76
  77   const T* ptr;
  78 };
  79
  80 // To sort by label:
  81 // std::sort(vect.begin(), vect.end(), LabelPtrLabelLess<Config>());
  82 template<typename T>
  83 struct LabelPtrLabelLess : public std::binary_function<LabelPtrPair<T>,
  84                                                        LabelPtrPair<T>,
  85                                                        bool> {
  86   bool operator()(const LabelPtrPair<T>& a, const LabelPtrPair<T>& b) const {
  87     return a.label < b.label;
  88   }
  89 };
  90
  91 // Default comparison operators -----------------------------------------------
  92 //
  93 // The default hash and comparison operators operate on the label, which should
  94 // always be valid, whereas the pointer is sometimes null.
  95
  96 template<typename T> inline bool operator==(const LabelPtrPair<T>& a,
  97                                             const LabelPtrPair<T>& b) {
  98   return a.label == b.label;
  99 }
 100
 101 template<typename T> inline bool operator<(const LabelPtrPair<T>& a,
 102                                            const LabelPtrPair<T>& b) {
 103   return a.label < b.label;
 104 }
 105
 106 namespace BASE_HASH_NAMESPACE {
 107
 108 template<typename T> struct hash< LabelPtrPair<T> > {
 109   std::size_t operator()(const LabelPtrPair<T>& v) const {
 110     BASE_HASH_NAMESPACE::hash<Label> h;
 111     return h(v.label);
 112   }
 113 };
 114
 115 }  // namespace BASE_HASH_NAMESPACE
 116
 117 #endif  // TOOLS_GN_LABEL_PTR_H_