config_values_extractors.h revision 0f1bc08d4cfcc34181b0b5cbf065c40f687bf740 
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
16struct 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());
29class 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
74template<typename T, class Writer>
75inline 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.
88template<typename T, class Writer>
89inline 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.
99void 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