src/sqlite3.hxx

   1 /*
   2     Copyright 2013 Karel Matas
   3
   4     This program is free software: you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation, either version 3 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16 */
  17
  18
  19 /*! \file sqlite3.hxx
  20 * \date 2013/06/10
  21 */
  22
  23 #ifndef _SQLITE3_HXX
  24 #define _SQLITE3_HXX
  25
  26 #include "3rdparty/sqlite3.h"
  27 #include <exception>
  28 #include <vector>
  29 #include <string>
  30 #include <sstream>
  31 #include <cstring>
  32 #include <stdexcept>
  33
  34 using std::vector;
  35 using std::string;
  36
  37 namespace SQLite3 {
  38
  39 //////////////////////////////////////////////////////////////////////////
  40 // EXCEPTIONS
  41
  42 class CantOpenDatabase : public std::exception {
  43   private:
  44     string msg_;
  45   public:
  46     CantOpenDatabase(const string &filename): msg_(filename) {};
  47     const char *what() const noexcept {return msg_.c_str();};
  48 };
  49
  50
  51 class DatabaseError : public std::exception {
  52   private:
  53     string msg_;
  54     string query_;
  55   public:
  56     DatabaseError(const string &msg, const string &query)
  57       : msg_(msg.c_str()), query_(query){};
  58     const char *what() const noexcept {return msg_.c_str();};
  59     //! Returns details about executed query.
  60     const char *query() const {return query_.c_str();};
  61 };
  62
  63
  64 //////////////////////////////////////////////////////////////////////////
  65 // FUNCTIONS
  66
  67 /*!
  68 * Replaces ' with '' and " with \".
  69 */
  70 inline string escape ( const char *s )
  71 {
  72   if ( !strlen(s) )
  73     return "";
  74
  75   std::stringstream ss;
  76   for ( size_t i=0; i<strlen(s); i++ ){
  77     ss << s[i];
  78     if ( s[i] == '\'' )
  79       ss << "'";
  80     else if ( s[i] == '"' )
  81       ss << "\"";
  82   }
  83   return ss.str();
  84 }
  85
  86 // overloaded inline function must be placed after base inline function
  87 inline string escape ( const string &s ){ return escape(s.c_str()); }
  88
  89
  90 //////////////////////////////////////////////////////////////////////////
  91 // class SQLite3
  92
  93 class SQLite3
  94 {
  95   private:
  96     sqlite3 *db_ = nullptr;
  97     vector<string> data_ = {};
  98     vector<string> columns_ = {};
  99
 100   public:
 101     /*!
 102     * Constructor. Calls open().
 103     * \param filename Name of the sqlite3 database file.
 104     */
 105     SQLite3 ( const char *filename ) {  open( filename );  }
 106
 107     //! Destructor. Calls close().
 108     ~SQLite3 () { close(); }
 109
 110     /*!
 111     * Opens sqlite3 database.
 112     * \exception CantOpenDatabase
 113     * \param filename NAme of the sqlite3 database.
 114     */
 115           void open( const char *filename ){
 116             if( sqlite3_open(filename, &db_) != SQLITE_OK ) {
 117         close();
 118         throw CantOpenDatabase(filename);
 119       }
 120     }
 121
 122     //! Closes database.
 123           void close() { sqlite3_close(db_); }
 124
 125     //! sqlite3_exec calls this function for each row
 126     static int callback(void *parent, int argc, char **argv, char **column) {
 127       // put column names into vector<string> columns_
 128       if ( ((SQLite3*)parent)->data_.empty() ) {
 129         for( int i=0; i<argc; i++ )
 130           ((SQLite3*)parent)->columns_.push_back( column[i] );
 131       }
 132       // put row data into vector<string> data_
 133       for( int i=0; i<argc; i++ )
 134         ((SQLite3*)parent)->data_.push_back( argv[i] ? argv[i] : "" );
 135       return 0;
 136     }
 137
 138     //! Returns all data (same data as query() ).
 139     inline vector<string> data () const { return data_; };
 140
 141     //! Returns column names
 142     inline vector<string> columns () const { return columns_; };
 143
 144     //! Returns # of returned rows ( data().size()/columns().size() )
 145     inline size_t result_rows () const
 146       { return data_.empty() ? 0:data_.size()/columns_.size(); };
 147
 148     /*!
 149     * Executes SQLite query.
 150     * Query can contain more commands separated with semicolon.
 151     * \exception CantOpenDatabase
 152     * \exception DatabaseError
 153     * \param query  SQLite query
 154     * \return Vector of strings with query results. Order of elements is: row1_col1, row1_col2, .. row1_colN, row2_col1, .. row2_colN, .. , rowM_col1, .., rowM_colN
 155     * \sa script()
 156     */
 157           vector<string> query( const char *query ){
 158       if ( !db_ )
 159         throw CantOpenDatabase("SQLite3::query(): db_ is NULL");
 160       char *err = nullptr;
 161       if ( !data_.empty() )       data_.clear();
 162       if ( !columns_.empty() )    columns_.clear();
 163       int rc = sqlite3_exec( db_, query, SQLite3::callback, (void*)this, &err);
 164       string s(err?err:"");
 165       sqlite3_free(err);
 166       if ( rc != SQLITE_OK )
 167         throw DatabaseError(s,query);
 168       return data_;
 169     };
 170
 171   /*!
 172   * Loads and executes file containing SQLite script.
 173   * \exception std::runtime_error
 174   * \param path path to script file
 175   * \sa query()
 176   */
 177   void script ( const char *path ){
 178     std::ifstream f(path);
 179     if ( f.is_open() ){
 180       f.seekg( 0, f.end );
 181       size_t size = f.tellg();
 182       f.seekg( 0, f.beg );
 183       if ( size > 0 ){
 184         char buff[ size+1 ];
 185         f.read( buff, size );
 186         f.close();
 187         query( buff );
 188       }
 189       else
 190         throw std::runtime_error("File has zero length: " + string(path));
 191     }
 192     else
 193       throw std::runtime_error("Can't open file: " + string(path));
 194   }
 195 };
 196
 197 } // namespace sqlite3
 198 #endif //_SQLITE3_HXX