tools/gn/config_values_extractors.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_CONFIG_VALUES_EXTRACTORS_H_
   6 #define TOOLS_GN_CONFIG_VALUES_EXTRACTORS_H_
   7
   8 #include <ostream>
   9 #include <string>
  10 #include <vector>
  11
  12 #include "tools/gn/config.h"
  13 #include "tools/gn/config_values.h"
  14 #include "tools/gn/target.h"
  15
  16 struct EscapeOptions;
  17
  18 // Provides a way to iterate through all ConfigValues applying to a given
  19 // target. This is more complicated than normal because the target has a list
  20 // of configs applying to it, and also config values on the target itself.
  21 //
  22 // This iterator allows one to iterate through all of these in a defined order
  23 // in one convenient loop. The order is defined to be the ConfigValues on the
  24 // target itself first, then the applying configs, in order.
  25 //
  26 // Example:
  27 //   for (ConfigValueIterator iter(target); !iter.done(); iter.Next())
  28 //     DoSomething(iter->cur());
  29 class ConfigValuesIterator {
  30  public:
  31   explicit ConfigValuesIterator(const Target* target)
  32       : target_(target),
  33         cur_index_(-1) {
  34   }
  35
  36   bool done() const {
  37     return cur_index_ >= static_cast<int>(target_->configs().size());
  38   }
  39
  40   const ConfigValues& cur() const {
  41     if (cur_index_ == -1)
  42       return target_->config_values();
  43     return target_->configs()[cur_index_].ptr->config_values();
  44   }
  45
  46   // Returns the origin of who added this config, if any. This will alwsya be
  47   // null for the config values of a target itself.
  48   const ParseNode* origin() const {
  49     if (cur_index_ == -1)
  50       return nullptr;
  51     return target_->configs()[cur_index_].origin;
  52   }
  53
  54   void Next() {
  55     cur_index_++;
  56   }
  57
  58   // Returns the config holding the current config values, or NULL for those
  59   // config values associated with the target itself.
  60   const Config* GetCurrentConfig() const {
  61     if (cur_index_ == -1)
  62       return nullptr;
  63     return target_->configs()[cur_index_].ptr;
  64   }
  65
  66  private:
  67   const Target* target_;
  68
  69   // Represents an index into the target_'s configs() or, when -1, the config
  70   // values on the target itself.
  71   int cur_index_;
  72 };
  73
  74 template<typename T, class Writer>
  75 inline void ConfigValuesToStream(
  76     const ConfigValues& values,
  77     const std::vector<T>& (ConfigValues::* getter)() const,
  78     const Writer& writer,
  79     std::ostream& out) {
  80   const std::vector<T>& v = (values.*getter)();
  81   for (size_t i = 0; i < v.size(); i++)
  82     writer(v[i], out);
  83 };
  84
  85 // Writes a given config value that applies to a given target. This collects
  86 // all values from the target itself and all configs that apply, and writes
  87 // then in order.
  88 template<typename T, class Writer>
  89 inline void RecursiveTargetConfigToStream(
  90     const Target* target,
  91     const std::vector<T>& (ConfigValues::* getter)() const,
  92     const Writer& writer,
  93     std::ostream& out) {
  94   for (ConfigValuesIterator iter(target); !iter.done(); iter.Next())
  95     ConfigValuesToStream(iter.cur(), getter, writer, out);
  96 }
  97
  98 // Writes the values out as strings with no transformation.
  99 void RecursiveTargetConfigStringsToStream(
 100     const Target* target,
 101     const std::vector<std::string>& (ConfigValues::* getter)() const,
 102     const EscapeOptions& escape_options,
 103     std::ostream& out);
 104
 105 #endif  // TOOLS_GN_CONFIG_VALUES_EXTRACTORS_H_