1 | // Copyright 2011 Google Inc. All Rights Reserved. |
2 | // |
3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
4 | // you may not use this file except in compliance with the License. |
5 | // You may obtain a copy of the License at |
6 | // |
7 | // http://www.apache.org/licenses/LICENSE-2.0 |
8 | // |
9 | // Unless required by applicable law or agreed to in writing, software |
10 | // distributed under the License is distributed on an "AS IS" BASIS, |
11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
12 | // See the License for the specific language governing permissions and |
13 | // limitations under the License. |
14 | |
15 | #ifndef NINJA_EVAL_ENV_H_ |
16 | #define NINJA_EVAL_ENV_H_ |
17 | |
18 | #include <map> |
19 | #include <string> |
20 | #include <vector> |
21 | |
22 | #include "string_piece.h" |
23 | |
24 | struct Rule; |
25 | |
26 | /// An interface for a scope for variable (e.g. "$foo") lookups. |
27 | struct Env { |
28 | virtual ~Env() {} |
29 | virtual std::string LookupVariable(const std::string& var) = 0; |
30 | }; |
31 | |
32 | /// A tokenized string that contains variable references. |
33 | /// Can be evaluated relative to an Env. |
34 | struct EvalString { |
35 | /// @return The evaluated string with variable expanded using value found in |
36 | /// environment @a env. |
37 | std::string Evaluate(Env* env) const; |
38 | |
39 | /// @return The string with variables not expanded. |
40 | std::string Unparse() const; |
41 | |
42 | void Clear() { parsed_.clear(); } |
43 | bool empty() const { return parsed_.empty(); } |
44 | |
45 | void AddText(StringPiece text); |
46 | void AddSpecial(StringPiece text); |
47 | |
48 | /// Construct a human-readable representation of the parsed state, |
49 | /// for use in tests. |
50 | std::string Serialize() const; |
51 | |
52 | private: |
53 | enum TokenType { RAW, SPECIAL }; |
54 | typedef std::vector<std::pair<std::string, TokenType> > TokenList; |
55 | TokenList parsed_; |
56 | }; |
57 | |
58 | /// An invocable build command and associated metadata (description, etc.). |
59 | struct Rule { |
60 | explicit Rule(const std::string& name) : name_(name) {} |
61 | |
62 | const std::string& name() const { return name_; } |
63 | |
64 | void AddBinding(const std::string& key, const EvalString& val); |
65 | |
66 | static bool IsReservedBinding(const std::string& var); |
67 | |
68 | const EvalString* GetBinding(const std::string& key) const; |
69 | |
70 | private: |
71 | // Allow the parsers to reach into this object and fill out its fields. |
72 | friend struct ManifestParser; |
73 | |
74 | std::string name_; |
75 | typedef std::map<std::string, EvalString> Bindings; |
76 | Bindings bindings_; |
77 | }; |
78 | |
79 | /// An Env which contains a mapping of variables to values |
80 | /// as well as a pointer to a parent scope. |
81 | struct BindingEnv : public Env { |
82 | BindingEnv() : parent_(NULL) {} |
83 | explicit BindingEnv(BindingEnv* parent) : parent_(parent) {} |
84 | |
85 | virtual ~BindingEnv() {} |
86 | virtual std::string LookupVariable(const std::string& var); |
87 | |
88 | void AddRule(const Rule* rule); |
89 | const Rule* LookupRule(const std::string& rule_name); |
90 | const Rule* LookupRuleCurrentScope(const std::string& rule_name); |
91 | const std::map<std::string, const Rule*>& GetRules() const; |
92 | |
93 | void AddBinding(const std::string& key, const std::string& val); |
94 | |
95 | /// This is tricky. Edges want lookup scope to go in this order: |
96 | /// 1) value set on edge itself (edge_->env_) |
97 | /// 2) value set on rule, with expansion in the edge's scope |
98 | /// 3) value set on enclosing scope of edge (edge_->env_->parent_) |
99 | /// This function takes as parameters the necessary info to do (2). |
100 | std::string LookupWithFallback(const std::string& var, const EvalString* eval, |
101 | Env* env); |
102 | |
103 | private: |
104 | std::map<std::string, std::string> bindings_; |
105 | std::map<std::string, const Rule*> rules_; |
106 | BindingEnv* parent_; |
107 | }; |
108 | |
109 | #endif // NINJA_EVAL_ENV_H_ |
110 | |