1 //
2 // Copyright (C) 2017 The Android Open Source Project
3 //
4 // Licensed under the Apache License, Version 2.0 (the "License");
5 // you may not use this file except in compliance with the License.
6 // You may obtain a copy of the License at
7 //
8 //      http://www.apache.org/licenses/LICENSE-2.0
9 //
10 // Unless required by applicable law or agreed to in writing, software
11 // distributed under the License is distributed on an "AS IS" BASIS,
12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 // See the License for the specific language governing permissions and
14 // limitations under the License.
15 //
16 
17 #ifndef PROPERTY_INFO_SERIALIZER_TRIE_BUILDER_H
18 #define PROPERTY_INFO_SERIALIZER_TRIE_BUILDER_H
19 
20 #include <memory>
21 #include <set>
22 #include <string>
23 #include <vector>
24 
25 namespace android {
26 namespace properties {
27 
28 struct PropertyEntryBuilder {
PropertyEntryBuilderPropertyEntryBuilder29   PropertyEntryBuilder() : context(nullptr), type(nullptr) {}
PropertyEntryBuilderPropertyEntryBuilder30   PropertyEntryBuilder(const std::string& name, const std::string* context, const std::string* type)
31       : name(name), context(context), type(type) {}
32   std::string name;
33   const std::string* context;
34   const std::string* type;
35 };
36 
37 class TrieBuilderNode {
38  public:
TrieBuilderNode(const std::string & name)39   TrieBuilderNode(const std::string& name) : property_entry_(name, nullptr, nullptr) {}
40 
FindChild(const std::string & name)41   TrieBuilderNode* FindChild(const std::string& name) {
42     for (auto& child : children_) {
43       if (child.name() == name) return &child;
44     }
45     return nullptr;
46   }
47 
FindChild(const std::string & name)48   const TrieBuilderNode* FindChild(const std::string& name) const {
49     for (const auto& child : children_) {
50       if (child.name() == name) return &child;
51     }
52     return nullptr;
53   }
54 
AddChild(const std::string & name)55   TrieBuilderNode* AddChild(const std::string& name) { return &children_.emplace_back(name); }
56 
AddPrefixContext(const std::string & prefix,const std::string * context,const std::string * type)57   bool AddPrefixContext(const std::string& prefix, const std::string* context,
58                         const std::string* type) {
59     if (std::find_if(prefixes_.begin(), prefixes_.end(),
60                      [&prefix](const auto& t) { return t.name == prefix; }) != prefixes_.end()) {
61       return false;
62     }
63 
64     prefixes_.emplace_back(prefix, context, type);
65     return true;
66   }
67 
AddExactMatchContext(const std::string & exact_match,const std::string * context,const std::string * type)68   bool AddExactMatchContext(const std::string& exact_match, const std::string* context,
69                             const std::string* type) {
70     if (std::find_if(exact_matches_.begin(), exact_matches_.end(), [&exact_match](const auto& t) {
71           return t.name == exact_match;
72         }) != exact_matches_.end()) {
73       return false;
74     }
75 
76     exact_matches_.emplace_back(exact_match, context, type);
77     return true;
78   }
79 
name()80   const std::string& name() const { return property_entry_.name; }
context()81   const std::string* context() const { return property_entry_.context; }
set_context(const std::string * context)82   void set_context(const std::string* context) { property_entry_.context = context; }
type()83   const std::string* type() const { return property_entry_.type; }
set_type(const std::string * type)84   void set_type(const std::string* type) { property_entry_.type = type; }
85 
property_entry()86   const PropertyEntryBuilder property_entry() const { return property_entry_; }
87 
children()88   const std::vector<TrieBuilderNode>& children() const { return children_; }
prefixes()89   const std::vector<PropertyEntryBuilder>& prefixes() const { return prefixes_; }
exact_matches()90   const std::vector<PropertyEntryBuilder>& exact_matches() const { return exact_matches_; }
91 
92  private:
93   PropertyEntryBuilder property_entry_;
94   std::vector<TrieBuilderNode> children_;
95   std::vector<PropertyEntryBuilder> prefixes_;
96   std::vector<PropertyEntryBuilder> exact_matches_;
97 };
98 
99 class TrieBuilder {
100  public:
101   TrieBuilder(const std::string& default_context, const std::string& default_type);
102   bool AddToTrie(const std::string& name, const std::string& context, const std::string& type,
103                  bool exact, std::string* error);
104 
builder_root()105   const TrieBuilderNode builder_root() const { return builder_root_; }
contexts()106   const std::set<std::string>& contexts() const { return contexts_; }
types()107   const std::set<std::string>& types() const { return types_; }
108 
109  private:
110   bool AddToTrie(const std::string& name, const std::string* context, const std::string* type,
111                  bool exact, std::string* error);
112   const std::string* StringPointerFromContainer(const std::string& string,
113                                                 std::set<std::string>* container);
114 
115   TrieBuilderNode builder_root_;
116   std::set<std::string> contexts_;
117   std::set<std::string> types_;
118 };
119 
120 }  // namespace properties
121 }  // namespace android
122 
123 #endif
124