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// Copyright 2011 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef NINJA_EVAL_ENV_H_
#define NINJA_EVAL_ENV_H_
#include <map>
#include <string>
#include <vector>
using namespace std;
#include "string_piece.h"
struct Rule;
/// An interface for a scope for variable (e.g. "$foo") lookups.
struct Env {
virtual ~Env() {}
virtual string LookupVariable(const string& var) = 0;
};
/// A tokenized string that contains variable references.
/// Can be evaluated relative to an Env.
struct EvalString {
string Evaluate(Env* env) const;
void Clear() { parsed_.clear(); }
bool empty() const { return parsed_.empty(); }
void AddText(StringPiece text);
void AddSpecial(StringPiece text);
/// Construct a human-readable representation of the parsed state,
/// for use in tests.
string Serialize() const;
private:
enum TokenType { RAW, SPECIAL };
typedef vector<pair<string, TokenType> > TokenList;
TokenList parsed_;
};
/// An invokable build command and associated metadata (description, etc.).
struct Rule {
explicit Rule(const string& name) : name_(name) {}
const string& name() const { return name_; }
typedef map<string, EvalString> Bindings;
void AddBinding(const string& key, const EvalString& val);
static bool IsReservedBinding(const string& var);
const EvalString* GetBinding(const string& key) const;
private:
// Allow the parsers to reach into this object and fill out its fields.
friend struct ManifestParser;
string name_;
map<string, EvalString> bindings_;
};
/// An Env which contains a mapping of variables to values
/// as well as a pointer to a parent scope.
struct BindingEnv : public Env {
BindingEnv() : parent_(NULL) {}
explicit BindingEnv(BindingEnv* parent) : parent_(parent) {}
virtual ~BindingEnv() {}
virtual string LookupVariable(const string& var);
void AddRule(const Rule* rule);
const Rule* LookupRule(const string& rule_name);
const Rule* LookupRuleCurrentScope(const string& rule_name);
const map<string, const Rule*>& GetRules() const;
void AddBinding(const string& key, const string& val);
/// This is tricky. Edges want lookup scope to go in this order:
/// 1) value set on edge itself (edge_->env_)
/// 2) value set on rule, with expansion in the edge's scope
/// 3) value set on enclosing scope of edge (edge_->env_->parent_)
/// This function takes as parameters the necessary info to do (2).
string LookupWithFallback(const string& var, const EvalString* eval,
Env* env);
private:
map<string, string> bindings_;
map<string, const Rule*> rules_;
BindingEnv* parent_;
};
#endif // NINJA_EVAL_ENV_H_
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