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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_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 NULL;
     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 NULL;
     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_
    106