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      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 #if defined(COMPILER_GCC)
    109 template<typename T> struct hash< LabelPtrPair<T> > {
    110   std::size_t operator()(const LabelPtrPair<T>& v) const {
    111     BASE_HASH_NAMESPACE::hash<Label> h;
    112     return h(v.label);
    113   }
    114 };
    115 #elif defined(COMPILER_MSVC)
    116 template<typename T>
    117 inline size_t hash_value(const LabelPtrPair<T>& v) {
    118   return BASE_HASH_NAMESPACE::hash_value(v.label);
    119 }
    120 #endif  // COMPILER...
    121 
    122 }  // namespace BASE_HASH_NAMESPACE
    123 
    124 #endif  // TOOLS_GN_LABEL_PTR_H_
    125