cu29_unifiedlog/
noop.rs

1use crate::{
2    SECTION_HEADER_COMPACT_SIZE, SECTION_MAGIC, SectionHandle, SectionHeader, SectionStorage,
3    UnifiedLogStatus, UnifiedLogWrite,
4};
5use bincode::Encode;
6use bincode::config::standard;
7use bincode::enc::EncoderImpl;
8use bincode::enc::write::SizeWriter;
9use bincode::error::EncodeError;
10use cu29_traits::{
11    CuResult, ObservedWriter, UnifiedLogType, abort_observed_encode, begin_observed_encode,
12    finish_observed_encode,
13};
14
15#[derive(Debug, Default)]
16pub struct NoopSectionStorage {
17    bytes_written: usize,
18}
19
20impl SectionStorage for NoopSectionStorage {
21    fn initialize<E: Encode>(&mut self, header: &E) -> Result<usize, EncodeError> {
22        let header_size = encoded_size(header)?;
23        self.bytes_written = header_size;
24        Ok(header_size)
25    }
26
27    fn post_update_header<E: Encode>(&mut self, header: &E) -> Result<usize, EncodeError> {
28        encoded_size(header)
29    }
30
31    fn append<E: Encode>(&mut self, entry: &E) -> Result<usize, EncodeError> {
32        let size = encoded_size(entry)?;
33        self.bytes_written = self.bytes_written.saturating_add(size);
34        Ok(size)
35    }
36
37    fn flush(&mut self) -> CuResult<usize> {
38        Ok(self.bytes_written)
39    }
40}
41
42#[derive(Debug, Default)]
43pub struct NoopLogger {
44    total_used_space: usize,
45    total_allocated_space: usize,
46}
47
48impl NoopLogger {
49    pub fn new() -> Self {
50        Self::default()
51    }
52}
53
54impl UnifiedLogWrite<NoopSectionStorage> for NoopLogger {
55    fn add_section(
56        &mut self,
57        entry_type: UnifiedLogType,
58        requested_section_size: usize,
59    ) -> CuResult<SectionHandle<NoopSectionStorage>> {
60        let allocated_size = requested_section_size.max(SECTION_HEADER_COMPACT_SIZE as usize);
61        let section_header = SectionHeader {
62            magic: SECTION_MAGIC,
63            block_size: SECTION_HEADER_COMPACT_SIZE,
64            entry_type,
65            offset_to_next_section: allocated_size.min(u32::MAX as usize) as u32,
66            used: 0,
67            is_open: true,
68        };
69
70        self.total_allocated_space = self.total_allocated_space.saturating_add(allocated_size);
71        SectionHandle::create(section_header, NoopSectionStorage::default())
72    }
73
74    fn flush_section(&mut self, section: &mut SectionHandle<NoopSectionStorage>) {
75        section.mark_closed();
76        let _ = section.post_update_header();
77        if let Ok(used) = section.get_storage_mut().flush() {
78            self.total_used_space = self.total_used_space.saturating_add(used);
79        }
80    }
81
82    fn status(&self) -> UnifiedLogStatus {
83        UnifiedLogStatus {
84            total_used_space: self.total_used_space,
85            total_allocated_space: self.total_allocated_space,
86        }
87    }
88}
89
90fn encoded_size<E: Encode>(value: &E) -> Result<usize, EncodeError> {
91    begin_observed_encode();
92    let result = (|| {
93        let mut encoder =
94            EncoderImpl::<_, _>::new(ObservedWriter::new(SizeWriter::default()), standard());
95        value.encode(&mut encoder)?;
96        Ok(encoder.into_writer().into_inner().bytes_written)
97    })();
98    match result {
99        Ok(size) => {
100            debug_assert_eq!(size, finish_observed_encode());
101            Ok(size)
102        }
103        Err(err) => {
104            abort_observed_encode();
105            Err(err)
106        }
107    }
108}
cu29_unifiedlog/noop.rs

cu29_unifiedlog/
noop.rs
