sysio::chain::istream_snapshot_reader Class Reference

#include <snapshot.hpp>

Inheritance diagram for sysio::chain::istream_snapshot_reader:

Collaboration diagram for sysio::chain::istream_snapshot_reader:

Public Member Functions
	istream_snapshot_reader (std::istream &snapshot)
void	validate () const override
bool	has_section (const string &section_name) override
void	set_section (const string &section_name) override
bool	read_row (detail::abstract_snapshot_row_reader &row_reader) override
bool	empty () override
void	clear_section () override
void	return_to_header () override
Public Member Functions inherited from sysio::chain::snapshot_reader
template<typename F >
void	read_section (const std::string &section_name, F f)
template<typename T , typename F >
void	read_section (F f)
template<typename T >
bool	has_section (const std::string &suffix=std::string())
virtual	~snapshot_reader ()

Additional Inherited Members

Protected Member Functions inherited from sysio::chain::snapshot_reader

Detailed Description

Definition at line 348 of file snapshot.hpp.

Constructor & Destructor Documentation

istream_snapshot_reader()

sysio::chain::istream_snapshot_reader::istream_snapshot_reader ( std::istream & snapshot )

explicit

Definition at line 193 of file snapshot.cpp.

:snapshot(snapshot)
,header_pos(snapshot.tellg())
,num_rows(0)
,cur_row(0)
{
 
}

Member Function Documentation

clear_section()

void sysio::chain::istream_snapshot_reader::clear_section ( )

overridevirtual

Implements sysio::chain::snapshot_reader.

Definition at line 339 of file snapshot.cpp.

                                            {
   num_rows = 0;
   cur_row = 0;
}

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empty()

bool sysio::chain::istream_snapshot_reader::empty ( )

overridevirtual

Implements sysio::chain::snapshot_reader.

Definition at line 335 of file snapshot.cpp.

                                      {
   return num_rows == 0;
}

has_section()

bool sysio::chain::istream_snapshot_reader::has_section ( const string & section_name )

overridevirtual

Implements sysio::chain::snapshot_reader.

Definition at line 249 of file snapshot.cpp.

                                                                      {
   auto restore_pos = fc::make_scoped_exit([this,pos=snapshot.tellg()](){
      snapshot.seekg(pos);
   });
 
   const std::streamoff header_size = sizeof(ostream_snapshot_writer::magic_number) + sizeof(current_snapshot_version);
 
   auto next_section_pos = header_pos + header_size;
 
   while (true) {
      snapshot.seekg(next_section_pos);
      uint64_t section_size = 0;
      snapshot.read((char*)&section_size,sizeof(section_size));
      if (section_size == std::numeric_limits<uint64_t>::max()) {
         break;
      }
 
      next_section_pos = snapshot.tellg() + std::streamoff(section_size);
 
      uint64_t ignore = 0;
      snapshot.read((char*)&ignore,sizeof(ignore));
 
      bool match = true;
      for(auto c : section_name) {
         if(snapshot.get() != c) {
            match = false;
            break;
         }
      }
 
      if (match && snapshot.get() == 0) {
         return true;
      }
   }
 
   return false;
}

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read_row()

bool sysio::chain::istream_snapshot_reader::read_row ( detail::abstract_snapshot_row_reader & row_reader )

overridevirtual

Implements sysio::chain::snapshot_reader.

Definition at line 330 of file snapshot.cpp.

                                                                                       {
   row_reader.provide(snapshot);
   return ++cur_row < num_rows;
}

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return_to_header()

void sysio::chain::istream_snapshot_reader::return_to_header ( )

overridevirtual

Implements sysio::chain::snapshot_reader.

Definition at line 344 of file snapshot.cpp.

                                               {
   snapshot.seekg( header_pos );
   clear_section();
}

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set_section()

void sysio::chain::istream_snapshot_reader::set_section ( const string & section_name )

overridevirtual

Implements sysio::chain::snapshot_reader.

Definition at line 287 of file snapshot.cpp.

                                                                      {
   auto restore_pos = fc::make_scoped_exit([this,pos=snapshot.tellg()](){
      snapshot.seekg(pos);
   });
 
   const std::streamoff header_size = sizeof(ostream_snapshot_writer::magic_number) + sizeof(current_snapshot_version);
 
   auto next_section_pos = header_pos + header_size;
 
   while (true) {
      snapshot.seekg(next_section_pos);
      uint64_t section_size = 0;
      snapshot.read((char*)&section_size,sizeof(section_size));
      if (section_size == std::numeric_limits<uint64_t>::max()) {
         break;
      }
 
      next_section_pos = snapshot.tellg() + std::streamoff(section_size);
 
      uint64_t row_count = 0;
      snapshot.read((char*)&row_count,sizeof(row_count));
 
      bool match = true;
      for(auto c : section_name) {
         if(snapshot.get() != c) {
            match = false;
            break;
         }
      }
 
      if (match && snapshot.get() == 0) {
         cur_row = 0;
         num_rows = row_count;
 
         // leave the stream at the right point
         restore_pos.cancel();
         return;
      }
   }
 
   SYS_THROW(snapshot_exception, "Binary snapshot has no section named ${n}", ("n", section_name));
}

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validate()

void sysio::chain::istream_snapshot_reader::validate ( ) const

overridevirtual

Implements sysio::chain::snapshot_reader.

Definition at line 202 of file snapshot.cpp.

                                             {
   // make sure to restore the read pos
   auto restore_pos = fc::make_scoped_exit([this,pos=snapshot.tellg(),ex=snapshot.exceptions()](){
      snapshot.seekg(pos);
      snapshot.exceptions(ex);
   });
 
   snapshot.exceptions(std::istream::failbit|std::istream::eofbit);
 
   try {
      // validate totem
      auto expected_totem = ostream_snapshot_writer::magic_number;
      decltype(expected_totem) actual_totem;
      snapshot.read((char*)&actual_totem, sizeof(actual_totem));
      SYS_ASSERT(actual_totem == expected_totem, snapshot_exception,
                 "Binary snapshot has unexpected magic number!");
 
      // validate version
      auto expected_version = current_snapshot_version;
      decltype(expected_version) actual_version;
      snapshot.read((char*)&actual_version, sizeof(actual_version));
      SYS_ASSERT(actual_version == expected_version, snapshot_exception,
                 "Binary snapshot is an unsuppored version.  Expected : ${expected}, Got: ${actual}",
                 ("expected", expected_version)("actual", actual_version));
 
      while (validate_section()) {}
   } catch( const std::exception& e ) {  \
      snapshot_exception fce(FC_LOG_MESSAGE( warn, "Binary snapshot validation threw IO exception (${what})",("what",e.what())));
      throw fce;
   }
}

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The documentation for this class was generated from the following files:

• libraries/chain/include/sysio/chain/snapshot.hpp
• libraries/chain/snapshot.cpp