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      1 /*
      2  * Copyright (C) 2010 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 _INIT_INIT_PARSER_H_
     18 #define _INIT_INIT_PARSER_H_
     19 
     20 #include <map>
     21 #include <memory>
     22 #include <string>
     23 #include <vector>
     24 
     25 //  SectionParser is an interface that can parse a given 'section' in init.
     26 //
     27 //  You can implement up to 4 functions below, with ParseSection() being mandatory.
     28 //  The first two function return bool with false indicating a failure and has a std::string* err
     29 //  parameter into which an error string can be written.  It will be reported along with the
     30 //  filename and line number of where the error occurred.
     31 //
     32 //  1) bool ParseSection(std::vector<std::string>&& args, const std::string& filename,
     33 //                       int line, std::string* err)
     34 //    This function is called when a section is first encountered.
     35 //
     36 //  2) bool ParseLineSection(std::vector<std::string>&& args, int line, std::string* err)
     37 //    This function is called on each subsequent line until the next section is encountered.
     38 //
     39 //  3) bool EndSection()
     40 //    This function is called either when a new section is found or at the end of the file.
     41 //    It indicates that parsing of the current section is complete and any relevant objects should
     42 //    be committed.
     43 //
     44 //  4) bool EndFile()
     45 //    This function is called at the end of the file.
     46 //    It indicates that the parsing has completed and any relevant objects should be committed.
     47 
     48 namespace android {
     49 namespace init {
     50 
     51 class SectionParser {
     52   public:
     53     virtual ~SectionParser() {}
     54     virtual bool ParseSection(std::vector<std::string>&& args, const std::string& filename,
     55                               int line, std::string* err) = 0;
     56     virtual bool ParseLineSection(std::vector<std::string>&&, int, std::string*) { return true; };
     57     virtual void EndSection(){};
     58     virtual void EndFile(){};
     59 };
     60 
     61 class Parser {
     62   public:
     63     //  LineCallback is the type for callbacks that can parse a line starting with a given prefix.
     64     //
     65     //  They take the form of bool Callback(std::vector<std::string>&& args, std::string* err)
     66     //
     67     //  Similar to ParseSection() and ParseLineSection(), this function returns bool with false
     68     //  indicating a failure and has an std::string* err parameter into which an error string can
     69     //  be written.
     70     using LineCallback = std::function<bool(std::vector<std::string>&&, std::string*)>;
     71 
     72     // TODO: init is the only user of this as a singleton; remove it.
     73     static Parser& GetInstance();
     74 
     75     Parser();
     76 
     77     bool ParseConfig(const std::string& path);
     78     void AddSectionParser(const std::string& name, std::unique_ptr<SectionParser> parser);
     79     void AddSingleLineParser(const std::string& prefix, LineCallback callback);
     80     void set_is_system_etc_init_loaded(bool loaded) { is_system_etc_init_loaded_ = loaded; }
     81     void set_is_vendor_etc_init_loaded(bool loaded) { is_vendor_etc_init_loaded_ = loaded; }
     82     void set_is_odm_etc_init_loaded(bool loaded) { is_odm_etc_init_loaded_ = loaded; }
     83     bool is_system_etc_init_loaded() { return is_system_etc_init_loaded_; }
     84     bool is_vendor_etc_init_loaded() { return is_vendor_etc_init_loaded_; }
     85     bool is_odm_etc_init_loaded() { return is_odm_etc_init_loaded_; }
     86 
     87   private:
     88     void ParseData(const std::string& filename, const std::string& data);
     89     bool ParseConfigFile(const std::string& path);
     90     bool ParseConfigDir(const std::string& path);
     91 
     92     std::map<std::string, std::unique_ptr<SectionParser>> section_parsers_;
     93     std::vector<std::pair<std::string, LineCallback>> line_callbacks_;
     94     bool is_system_etc_init_loaded_ = false;
     95     bool is_vendor_etc_init_loaded_ = false;
     96     bool is_odm_etc_init_loaded_ = false;
     97 };
     98 
     99 }  // namespace init
    100 }  // namespace android
    101 
    102 #endif
    103