From be5fcde4989ac883201a1895be519f63fa6e6dd4 Mon Sep 17 00:00:00 2001
From: Jan Tuomi <jan@jantuomi.fi>
Date: Fri, 17 Jan 2025 12:34:41 +0200
Subject: Refactor interfaces to use more moves, remove log_reader_reverse

---
 log_db/src/log_reader_reverse.rs | 118 ---------------------------------------
 1 file changed, 118 deletions(-)
 delete mode 100644 log_db/src/log_reader_reverse.rs

(limited to 'log_db/src/log_reader_reverse.rs')

diff --git a/log_db/src/log_reader_reverse.rs b/log_db/src/log_reader_reverse.rs
deleted file mode 100644
index ef2b0dc..0000000
--- a/log_db/src/log_reader_reverse.rs
+++ /dev/null
@@ -1,118 +0,0 @@
-use super::common::*;
-use super::record::*;
-use std::fs::{self};
-use std::io::{self, Read, Seek};
-
-pub struct ReverseLogReader {
-    /// The contents of the metadata file are read into this buffer in one go.
-    metadata_buf: Vec<u8>,
-
-    /// The data log file that is read based on offset + length information from the metadata file.
-    data_reader: io::BufReader<fs::File>,
-
-    /// The current position in metadata_buf.
-    metadata_pos: usize,
-}
-
-impl ReverseLogReader {
-    pub fn new(
-        mut metadata_file: fs::File,
-        data_file: fs::File,
-    ) -> Result<ReverseLogReader, io::Error> {
-        let mut metadata_buf = vec![];
-        metadata_file.seek(io::SeekFrom::Start(0))?;
-        metadata_file.read_to_end(&mut metadata_buf)?;
-        let len = metadata_buf.len();
-
-        let ret = ReverseLogReader {
-            metadata_buf,
-            data_reader: io::BufReader::new(data_file),
-            metadata_pos: len,
-        };
-        Ok(ret)
-    }
-
-    fn read_record(&mut self) -> Result<Option<Record>, io::Error> {
-        loop {
-            assert!(
-                (self.metadata_pos - METADATA_FILE_HEADER_SIZE) % 16 == 0,
-                "metadata_pos is not aligned"
-            );
-            // Return None if we have read the entire metadata file and
-            // reached the end of the header
-            if self.metadata_pos == METADATA_FILE_HEADER_SIZE {
-                return Ok(None);
-            }
-
-            self.metadata_pos -= 16;
-            let i = self.metadata_pos; // shorter alias
-
-            // First u64 is the offset of the record in the data file, second is the length of the record
-            let entry_offset = u64::from_be_bytes(self.metadata_buf[i..i + 8].try_into().unwrap());
-            let entry_length =
-                u64::from_be_bytes(self.metadata_buf[i + 8..i + 16].try_into().unwrap());
-
-            if entry_offset == 0 && entry_length == 0 {
-                // This is an unused entry in the metadata file, skip
-                continue;
-            }
-
-            self.data_reader.seek(io::SeekFrom::Start(entry_offset))?;
-            let mut result_buf = vec![0; entry_length as usize];
-            self.data_reader.read_exact(&mut result_buf)?;
-
-            let record = Record::deserialize(&result_buf);
-
-            assert!(
-                (self.metadata_pos - METADATA_FILE_HEADER_SIZE) % 16 == 0,
-                "metadata_pos is not aligned"
-            );
-
-            return Ok(Some(record));
-        }
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use std::path::Path;
-
-    #[test]
-    fn test_reverse_log_reader_fixture_db1() {
-        let _ = env_logger::builder().is_test(true).try_init();
-        let metadata_path = Path::new(TEST_RESOURCES_DIR).join("test_metadata_1");
-        let metadata_file = fs::OpenOptions::new()
-            .read(true)
-            .open(&metadata_path)
-            .expect("Failed to open file");
-        let data_file = fs::OpenOptions::new()
-            .read(true)
-            .open(Path::new(TEST_RESOURCES_DIR).join("test_data_1"))
-            .expect("Failed to open file");
-
-        let mut reverse_log_reader = ReverseLogReader::new(metadata_file, data_file).unwrap();
-
-        // There are two records in the log with "schema": Int
-
-        let last_record = reverse_log_reader
-            .next()
-            .expect("Failed to read the last record");
-        assert!(match &last_record.values[..] {
-            [Value::Bytes(bytes)] => bytes.len() == 256,
-            _ => false,
-        });
-
-        assert!(reverse_log_reader.next().is_none());
-    }
-}
-
-impl Iterator for ReverseLogReader {
-    type Item = Record;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        self.read_record().unwrap_or_else(|err| {
-            panic!("Error reading record: {:?}", err);
-        })
-    }
-}
-- 
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