feoxdb/storage/
format.rs

1use crate::constants::*;
2use crate::core::record::Record;
3use std::sync::atomic::Ordering;
4
5/// Trait for handling different record format versions
6pub trait RecordFormat: Send + Sync {
7    /// Calculate the size of a record on disk (excluding value)
8    fn record_header_size(&self, key_len: usize) -> usize;
9
10    /// Calculate total size including value
11    fn total_size(&self, key_len: usize, value_len: usize) -> usize;
12
13    /// Serialize a record to bytes for disk storage
14    fn serialize_record(&self, record: &Record, include_value: bool) -> Vec<u8>;
15
16    /// Parse a record from disk bytes (returns key, value_len, timestamp, ttl_expiry)
17    fn parse_record(&self, data: &[u8]) -> Option<(Vec<u8>, usize, u64, u64)>;
18
19    /// Get the offset where value data starts in the serialized format
20    fn value_offset(&self, key_len: usize) -> usize;
21}
22
23/// Version 1 format (no TTL support)
24pub struct FormatV1;
25
26impl RecordFormat for FormatV1 {
27    fn record_header_size(&self, key_len: usize) -> usize {
28        SECTOR_HEADER_SIZE + 2 + key_len + 8 + 8 // header + key_len(2) + key + value_len(8) + timestamp(8)
29    }
30
31    fn total_size(&self, key_len: usize, value_len: usize) -> usize {
32        self.record_header_size(key_len) + value_len
33    }
34
35    fn serialize_record(&self, record: &Record, include_value: bool) -> Vec<u8> {
36        let mut data = Vec::with_capacity(self.total_size(record.key.len(), record.value_len));
37
38        // Key length (2 bytes)
39        data.extend_from_slice(&(record.key.len() as u16).to_le_bytes());
40
41        // Key
42        data.extend_from_slice(&record.key);
43
44        // Value length (8 bytes)
45        data.extend_from_slice(&(record.value_len as u64).to_le_bytes());
46
47        // Timestamp (8 bytes)
48        data.extend_from_slice(&record.timestamp.to_le_bytes());
49
50        // Value (if requested)
51        if include_value {
52            if let Some(value) = record.value.read().as_ref() {
53                data.extend_from_slice(value);
54            }
55        }
56
57        data
58    }
59
60    fn parse_record(&self, data: &[u8]) -> Option<(Vec<u8>, usize, u64, u64)> {
61        if data.len() < SECTOR_HEADER_SIZE + 2 {
62            return None;
63        }
64
65        let mut offset = SECTOR_HEADER_SIZE + 2;
66        let key_len = u16::from_le_bytes(
67            data[SECTOR_HEADER_SIZE..SECTOR_HEADER_SIZE + 2]
68                .try_into()
69                .ok()?,
70        ) as usize;
71
72        if offset + key_len + 16 > data.len() {
73            return None;
74        }
75
76        let key = data[offset..offset + key_len].to_vec();
77        offset += key_len;
78
79        let value_len = u64::from_le_bytes(data[offset..offset + 8].try_into().ok()?) as usize;
80        offset += 8;
81
82        let timestamp = u64::from_le_bytes(data[offset..offset + 8].try_into().ok()?);
83
84        Some((key, value_len, timestamp, 0)) // No TTL in v1
85    }
86
87    fn value_offset(&self, key_len: usize) -> usize {
88        SECTOR_HEADER_SIZE + 2 + key_len + 8 + 8
89    }
90}
91
92/// Version 2 format (with TTL support)
93pub struct FormatV2;
94
95impl RecordFormat for FormatV2 {
96    fn record_header_size(&self, key_len: usize) -> usize {
97        SECTOR_HEADER_SIZE + 2 + key_len + 8 + 8 + 8 // header + key_len(2) + key + value_len(8) + timestamp(8) + ttl(8)
98    }
99
100    fn total_size(&self, key_len: usize, value_len: usize) -> usize {
101        self.record_header_size(key_len) + value_len
102    }
103
104    fn serialize_record(&self, record: &Record, include_value: bool) -> Vec<u8> {
105        let mut data = Vec::with_capacity(self.total_size(record.key.len(), record.value_len));
106
107        // Key length (2 bytes)
108        data.extend_from_slice(&(record.key.len() as u16).to_le_bytes());
109
110        // Key
111        data.extend_from_slice(&record.key);
112
113        // Value length (8 bytes)
114        data.extend_from_slice(&(record.value_len as u64).to_le_bytes());
115
116        // Timestamp (8 bytes)
117        data.extend_from_slice(&record.timestamp.to_le_bytes());
118
119        // TTL expiry (8 bytes) - always included in v2
120        data.extend_from_slice(&record.ttl_expiry.load(Ordering::Acquire).to_le_bytes());
121
122        // Value (if requested)
123        if include_value {
124            if let Some(value) = record.value.read().as_ref() {
125                data.extend_from_slice(value);
126            }
127        }
128
129        data
130    }
131
132    fn parse_record(&self, data: &[u8]) -> Option<(Vec<u8>, usize, u64, u64)> {
133        if data.len() < SECTOR_HEADER_SIZE + 2 {
134            return None;
135        }
136
137        let mut offset = SECTOR_HEADER_SIZE + 2;
138        let key_len = u16::from_le_bytes(
139            data[SECTOR_HEADER_SIZE..SECTOR_HEADER_SIZE + 2]
140                .try_into()
141                .ok()?,
142        ) as usize;
143
144        if offset + key_len + 24 > data.len() {
145            // 24 = value_len(8) + timestamp(8) + ttl(8)
146            return None;
147        }
148
149        let key = data[offset..offset + key_len].to_vec();
150        offset += key_len;
151
152        let value_len = u64::from_le_bytes(data[offset..offset + 8].try_into().ok()?) as usize;
153        offset += 8;
154
155        let timestamp = u64::from_le_bytes(data[offset..offset + 8].try_into().ok()?);
156        offset += 8;
157
158        let ttl_expiry = u64::from_le_bytes(data[offset..offset + 8].try_into().ok()?);
159
160        Some((key, value_len, timestamp, ttl_expiry))
161    }
162
163    fn value_offset(&self, key_len: usize) -> usize {
164        SECTOR_HEADER_SIZE + 2 + key_len + 8 + 8 + 8
165    }
166}
167
168/// Factory function to get the appropriate format handler based on version
169pub fn get_format(version: u32) -> Box<dyn RecordFormat> {
170    match version {
171        1 => Box::new(FormatV1),
172        2 => Box::new(FormatV2),
173        _ => Box::new(FormatV2), // Default to latest version
174    }
175}
feoxdb/storage/format.rs

feoxdb/storage/
format.rs
