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use common::BinarySerializable;
use compression::CompressedIntStream;
use directory::{ReadOnlySource, SourceRead};
use postings::FreqReadingOption;
use postings::TermInfo;
use postings::{BlockSegmentPostings, SegmentPostings};
use schema::FieldType;
use schema::IndexRecordOption;
use schema::Term;
use termdict::TermDictionary;
pub struct InvertedIndexReader {
termdict: TermDictionary,
postings_source: ReadOnlySource,
positions_source: ReadOnlySource,
record_option: IndexRecordOption,
total_num_tokens: u64,
}
impl InvertedIndexReader {
pub(crate) fn new(
termdict: TermDictionary,
postings_source: ReadOnlySource,
positions_source: ReadOnlySource,
record_option: IndexRecordOption,
) -> InvertedIndexReader {
let total_num_tokens_data = postings_source.slice(0, 8);
let mut total_num_tokens_cursor = total_num_tokens_data.as_slice();
let total_num_tokens = u64::deserialize(&mut total_num_tokens_cursor).unwrap_or(0u64);
InvertedIndexReader {
termdict,
postings_source: postings_source.slice_from(8),
positions_source,
record_option,
total_num_tokens,
}
}
pub fn empty(field_type: FieldType) -> InvertedIndexReader {
let record_option = field_type
.get_index_record_option()
.unwrap_or(IndexRecordOption::Basic);
InvertedIndexReader {
termdict: TermDictionary::empty(field_type),
postings_source: ReadOnlySource::empty(),
positions_source: ReadOnlySource::empty(),
record_option,
total_num_tokens: 0u64,
}
}
pub fn get_term_info(&self, term: &Term) -> Option<TermInfo> {
self.termdict.get(term.value_bytes())
}
pub fn terms(&self) -> &TermDictionary {
&self.termdict
}
pub fn reset_block_postings_from_terminfo(
&self,
term_info: &TermInfo,
block_postings: &mut BlockSegmentPostings,
) {
let offset = term_info.postings_offset as usize;
let end_source = self.postings_source.len();
let postings_slice = self.postings_source.slice(offset, end_source);
let postings_reader = SourceRead::from(postings_slice);
block_postings.reset(term_info.doc_freq as usize, postings_reader);
}
pub fn read_block_postings_from_terminfo(
&self,
term_info: &TermInfo,
requested_option: IndexRecordOption,
) -> BlockSegmentPostings {
let offset = term_info.postings_offset as usize;
let postings_data = self.postings_source.slice_from(offset);
let freq_reading_option = match (self.record_option, requested_option) {
(IndexRecordOption::Basic, _) => FreqReadingOption::NoFreq,
(_, IndexRecordOption::Basic) => FreqReadingOption::SkipFreq,
(_, _) => FreqReadingOption::ReadFreq,
};
BlockSegmentPostings::from_data(
term_info.doc_freq as usize,
SourceRead::from(postings_data),
freq_reading_option,
)
}
pub fn read_postings_from_terminfo(
&self,
term_info: &TermInfo,
option: IndexRecordOption,
) -> SegmentPostings {
let block_postings = self.read_block_postings_from_terminfo(term_info, option);
let position_stream = {
if option.has_positions() {
let position_offset = term_info.positions_offset;
let positions_source = self.positions_source.slice_from(position_offset as usize);
let mut stream = CompressedIntStream::wrap(positions_source);
stream.skip(term_info.positions_inner_offset as usize);
Some(stream)
} else {
None
}
};
SegmentPostings::from_block_postings(block_postings, position_stream)
}
pub fn total_num_tokens(&self) -> u64 {
self.total_num_tokens
}
pub fn read_postings(&self, term: &Term, option: IndexRecordOption) -> Option<SegmentPostings> {
let term_info = get!(self.get_term_info(term));
Some(self.read_postings_from_terminfo(&term_info, option))
}
pub(crate) fn read_postings_no_deletes(
&self,
term: &Term,
option: IndexRecordOption,
) -> Option<SegmentPostings> {
let term_info = get!(self.get_term_info(term));
Some(self.read_postings_from_terminfo(&term_info, option))
}
pub fn doc_freq(&self, term: &Term) -> u32 {
self.get_term_info(term)
.map(|term_info| term_info.doc_freq)
.unwrap_or(0u32)
}
}