254 lines
6.4 KiB
Odin
254 lines
6.4 KiB
Odin
|
package key_codec
|
||
|
|
|
||
|
|
import "core:bytes"
|
||
|
|
import "core:encoding/varint"
|
||
|
|
import "core:mem"
|
||
|
|
|
||
|
|
// Entity type prefix bytes for namespacing
|
||
|
|
Entity_Type :: enum u8 {
|
||
|
|
Meta = 0x01, // Table metadata
|
||
|
|
Data = 0x02, // Item data
|
||
|
|
GSI = 0x03, // Global secondary index
|
||
|
|
LSI = 0x04, // Local secondary index
|
||
|
|
}
|
||
|
|
|
||
|
|
// Encode a varint length prefix
|
||
|
|
encode_varint :: proc(buf: ^bytes.Buffer, value: int) {
|
||
|
|
temp: [10]byte
|
||
|
|
n := varint.encode_u64(temp[:], u64(value))
|
||
|
|
bytes.buffer_write(buf, temp[:n])
|
||
|
|
}
|
||
|
|
|
||
|
|
// Decode a varint length prefix
|
||
|
|
decode_varint :: proc(data: []byte, offset: ^int) -> (value: int, ok: bool) {
|
||
|
|
if offset^ >= len(data) {
|
||
|
|
return 0, false
|
||
|
|
}
|
||
|
|
|
||
|
|
val, n := varint.decode_u64(data[offset^:])
|
||
|
|
if n <= 0 {
|
||
|
|
return 0, false
|
||
|
|
}
|
||
|
|
|
||
|
|
offset^ += n
|
||
|
|
return int(val), true
|
||
|
|
}
|
||
|
|
|
||
|
|
// Build metadata key: [meta][table_name]
|
||
|
|
build_meta_key :: proc(table_name: string) -> []byte {
|
||
|
|
buf: bytes.Buffer
|
||
|
|
bytes.buffer_init_allocator(&buf, 0, 256, context.allocator)
|
||
|
|
|
||
|
|
// Write entity type
|
||
|
|
bytes.buffer_write_byte(&buf, u8(Entity_Type.Meta))
|
||
|
|
|
||
|
|
// Write table name with length prefix
|
||
|
|
encode_varint(&buf, len(table_name))
|
||
|
|
bytes.buffer_write_string(&buf, table_name)
|
||
|
|
|
||
|
|
return bytes.buffer_to_bytes(&buf)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Build data key: [data][table_name][pk_value][sk_value?]
|
||
|
|
build_data_key :: proc(table_name: string, pk_value: []byte, sk_value: Maybe([]byte)) -> []byte {
|
||
|
|
buf: bytes.Buffer
|
||
|
|
bytes.buffer_init_allocator(&buf, 0, 512, context.allocator)
|
||
|
|
|
||
|
|
// Write entity type
|
||
|
|
bytes.buffer_write_byte(&buf, u8(Entity_Type.Data))
|
||
|
|
|
||
|
|
// Write table name
|
||
|
|
encode_varint(&buf, len(table_name))
|
||
|
|
bytes.buffer_write_string(&buf, table_name)
|
||
|
|
|
||
|
|
// Write partition key
|
||
|
|
encode_varint(&buf, len(pk_value))
|
||
|
|
bytes.buffer_write(&buf, pk_value)
|
||
|
|
|
||
|
|
// Write sort key if present
|
||
|
|
if sk, ok := sk_value.?; ok {
|
||
|
|
encode_varint(&buf, len(sk))
|
||
|
|
bytes.buffer_write(&buf, sk)
|
||
|
|
}
|
||
|
|
|
||
|
|
return bytes.buffer_to_bytes(&buf)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Build table prefix for scanning: [data][table_name]
|
||
|
|
build_table_prefix :: proc(table_name: string) -> []byte {
|
||
|
|
buf: bytes.Buffer
|
||
|
|
bytes.buffer_init_allocator(&buf, 0, 256, context.allocator)
|
||
|
|
|
||
|
|
// Write entity type
|
||
|
|
bytes.buffer_write_byte(&buf, u8(Entity_Type.Data))
|
||
|
|
|
||
|
|
// Write table name
|
||
|
|
encode_varint(&buf, len(table_name))
|
||
|
|
bytes.buffer_write_string(&buf, table_name)
|
||
|
|
|
||
|
|
return bytes.buffer_to_bytes(&buf)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Build partition prefix for querying: [data][table_name][pk_value]
|
||
|
|
build_partition_prefix :: proc(table_name: string, pk_value: []byte) -> []byte {
|
||
|
|
buf: bytes.Buffer
|
||
|
|
bytes.buffer_init_allocator(&buf, 0, 512, context.allocator)
|
||
|
|
|
||
|
|
// Write entity type
|
||
|
|
bytes.buffer_write_byte(&buf, u8(Entity_Type.Data))
|
||
|
|
|
||
|
|
// Write table name
|
||
|
|
encode_varint(&buf, len(table_name))
|
||
|
|
bytes.buffer_write_string(&buf, table_name)
|
||
|
|
|
||
|
|
// Write partition key
|
||
|
|
encode_varint(&buf, len(pk_value))
|
||
|
|
bytes.buffer_write(&buf, pk_value)
|
||
|
|
|
||
|
|
return bytes.buffer_to_bytes(&buf)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Build GSI key: [gsi][table_name][index_name][gsi_pk][gsi_sk?]
|
||
|
|
build_gsi_key :: proc(table_name: string, index_name: string, gsi_pk: []byte, gsi_sk: Maybe([]byte)) -> []byte {
|
||
|
|
buf: bytes.Buffer
|
||
|
|
bytes.buffer_init_allocator(&buf, 0, 512, context.allocator)
|
||
|
|
|
||
|
|
// Write entity type
|
||
|
|
bytes.buffer_write_byte(&buf, u8(Entity_Type.GSI))
|
||
|
|
|
||
|
|
// Write table name
|
||
|
|
encode_varint(&buf, len(table_name))
|
||
|
|
bytes.buffer_write_string(&buf, table_name)
|
||
|
|
|
||
|
|
// Write index name
|
||
|
|
encode_varint(&buf, len(index_name))
|
||
|
|
bytes.buffer_write_string(&buf, index_name)
|
||
|
|
|
||
|
|
// Write GSI partition key
|
||
|
|
encode_varint(&buf, len(gsi_pk))
|
||
|
|
bytes.buffer_write(&buf, gsi_pk)
|
||
|
|
|
||
|
|
// Write GSI sort key if present
|
||
|
|
if sk, ok := gsi_sk.?; ok {
|
||
|
|
encode_varint(&buf, len(sk))
|
||
|
|
bytes.buffer_write(&buf, sk)
|
||
|
|
}
|
||
|
|
|
||
|
|
return bytes.buffer_to_bytes(&buf)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Build LSI key: [lsi][table_name][index_name][pk][lsi_sk]
|
||
|
|
build_lsi_key :: proc(table_name: string, index_name: string, pk: []byte, lsi_sk: []byte) -> []byte {
|
||
|
|
buf: bytes.Buffer
|
||
|
|
bytes.buffer_init_allocator(&buf, 0, 512, context.allocator)
|
||
|
|
|
||
|
|
// Write entity type
|
||
|
|
bytes.buffer_write_byte(&buf, u8(Entity_Type.LSI))
|
||
|
|
|
||
|
|
// Write table name
|
||
|
|
encode_varint(&buf, len(table_name))
|
||
|
|
bytes.buffer_write_string(&buf, table_name)
|
||
|
|
|
||
|
|
// Write index name
|
||
|
|
encode_varint(&buf, len(index_name))
|
||
|
|
bytes.buffer_write_string(&buf, index_name)
|
||
|
|
|
||
|
|
// Write partition key
|
||
|
|
encode_varint(&buf, len(pk))
|
||
|
|
bytes.buffer_write(&buf, pk)
|
||
|
|
|
||
|
|
// Write LSI sort key
|
||
|
|
encode_varint(&buf, len(lsi_sk))
|
||
|
|
bytes.buffer_write(&buf, lsi_sk)
|
||
|
|
|
||
|
|
return bytes.buffer_to_bytes(&buf)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Key decoder for reading binary keys
|
||
|
|
Key_Decoder :: struct {
|
||
|
|
data: []byte,
|
||
|
|
pos: int,
|
||
|
|
}
|
||
|
|
|
||
|
|
decoder_init :: proc(data: []byte) -> Key_Decoder {
|
||
|
|
return Key_Decoder{data = data, pos = 0}
|
||
|
|
}
|
||
|
|
|
||
|
|
decoder_read_entity_type :: proc(decoder: ^Key_Decoder) -> (Entity_Type, bool) {
|
||
|
|
if decoder.pos >= len(decoder.data) {
|
||
|
|
return .Meta, false
|
||
|
|
}
|
||
|
|
|
||
|
|
entity_type := Entity_Type(decoder.data[decoder.pos])
|
||
|
|
decoder.pos += 1
|
||
|
|
return entity_type, true
|
||
|
|
}
|
||
|
|
|
||
|
|
decoder_read_segment :: proc(decoder: ^Key_Decoder) -> (segment: []byte, ok: bool) {
|
||
|
|
// Read length
|
||
|
|
length := decode_varint(decoder.data, &decoder.pos) or_return
|
||
|
|
|
||
|
|
// Read data
|
||
|
|
if decoder.pos + length > len(decoder.data) {
|
||
|
|
return nil, false
|
||
|
|
}
|
||
|
|
|
||
|
|
// Return slice (owned by caller via context.allocator)
|
||
|
|
segment = make([]byte, length, context.allocator)
|
||
|
|
copy(segment, decoder.data[decoder.pos:decoder.pos + length])
|
||
|
|
decoder.pos += length
|
||
|
|
|
||
|
|
return segment, true
|
||
|
|
}
|
||
|
|
|
||
|
|
decoder_read_segment_borrowed :: proc(decoder: ^Key_Decoder) -> (segment: []byte, ok: bool) {
|
||
|
|
// Read length
|
||
|
|
length := decode_varint(decoder.data, &decoder.pos) or_return
|
||
|
|
|
||
|
|
// Return borrowed slice
|
||
|
|
if decoder.pos + length > len(decoder.data) {
|
||
|
|
return nil, false
|
||
|
|
}
|
||
|
|
|
||
|
|
segment = decoder.data[decoder.pos:decoder.pos + length]
|
||
|
|
decoder.pos += length
|
||
|
|
|
||
|
|
return segment, true
|
||
|
|
}
|
||
|
|
|
||
|
|
decoder_has_more :: proc(decoder: ^Key_Decoder) -> bool {
|
||
|
|
return decoder.pos < len(decoder.data)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Decode a data key back into components
|
||
|
|
Decoded_Data_Key :: struct {
|
||
|
|
table_name: string,
|
||
|
|
pk_value: []byte,
|
||
|
|
sk_value: Maybe([]byte),
|
||
|
|
}
|
||
|
|
|
||
|
|
decode_data_key :: proc(key: []byte) -> (result: Decoded_Data_Key, ok: bool) {
|
||
|
|
decoder := decoder_init(key)
|
||
|
|
|
||
|
|
// Read and verify entity type
|
||
|
|
entity_type := decoder_read_entity_type(&decoder) or_return
|
||
|
|
if entity_type != .Data {
|
||
|
|
return {}, false
|
||
|
|
}
|
||
|
|
|
||
|
|
// Read table name
|
||
|
|
table_name_bytes := decoder_read_segment(&decoder) or_return
|
||
|
|
result.table_name = string(table_name_bytes)
|
||
|
|
|
||
|
|
// Read partition key
|
||
|
|
result.pk_value = decoder_read_segment(&decoder) or_return
|
||
|
|
|
||
|
|
// Read sort key if present
|
||
|
|
if decoder_has_more(&decoder) {
|
||
|
|
sk := decoder_read_segment(&decoder) or_return
|
||
|
|
result.sk_value = sk
|
||
|
|
}
|
||
|
|
|
||
|
|
return result, true
|
||
|
|
}
|