flesh out the scan a bit

This commit is contained in:
2026-02-15 14:10:48 -05:00
parent cf352dde23
commit 94296ae925
2 changed files with 165 additions and 4 deletions

View File

@@ -1,6 +1,7 @@
// Storage engine mapping DynamoDB operations to RocksDB // Storage engine mapping DynamoDB operations to RocksDB
package dynamodb package dynamodb
import "core:c"
import "core:fmt" import "core:fmt"
import "core:mem" import "core:mem"
import "core:slice" import "core:slice"
@@ -521,6 +522,113 @@ delete_item :: proc(engine: ^Storage_Engine, table_name: string, key: Item) -> S
return .None return .None
} }
scan :: proc(
engine: ^Storage_Engine,
table_name: string,
exclusive_start_key: Maybe([]byte),
limit: int,
) -> (Scan_Result, Storage_Error) {
table_lock := get_or_create_table_lock(engine, table_name)
sync.rw_mutex_shared_lock(table_lock)
defer sync.rw_mutex_shared_unlock(table_lock)
// Verify table exists
metadata, meta_err := get_table_metadata(engine, table_name)
if meta_err != .None {
return {}, meta_err
}
defer table_metadata_destroy(&metadata, engine.allocator)
// Create iterator
iter := rocksdb.rocksdb_create_iterator(engine.db.handle, engine.db.read_options)
if iter == nil {
return {}, .RocksDB_Error
}
defer rocksdb.rocksdb_iter_destroy(iter)
// Build table prefix to scan
table_prefix := build_table_prefix(table_name)
defer delete(table_prefix)
// Seek to start position
if start_key, has_start := exclusive_start_key.?; has_start {
// Resume from pagination token
rocksdb.rocksdb_iter_seek(iter, raw_data(start_key), c.size_t(len(start_key)))
// Skip the start key itself (it's exclusive)
if rocksdb.rocksdb_iter_valid(iter) != 0 {
rocksdb.rocksdb_iter_next(iter)
}
} else {
// Start from beginning of table
rocksdb.rocksdb_iter_seek(iter, raw_data(table_prefix), c.size_t(len(table_prefix)))
}
// Collect items
items := make([dynamic]Item, context.temp_allocator)
count := 0
last_key: Maybe([]byte) = nil
for rocksdb.rocksdb_iter_valid(iter) != 0 {
// Get current key
key_len: c.size_t
key_ptr := rocksdb.rocksdb_iter_key(iter, &key_len)
key_bytes := key_ptr[:key_len]
// Check if key still has table prefix
if !has_prefix(key_bytes, table_prefix) {
break
}
// Check limit
if count >= limit {
// Save this key as pagination token
last_key = slice.clone(key_bytes, engine.allocator)
break
}
// Get value
value_len: c.size_t
value_ptr := rocksdb.rocksdb_iter_value(iter, &value_len)
value_bytes := value_ptr[:value_len]
// Decode item
item, decode_ok := decode(value_bytes)
if !decode_ok {
// Skip corrupted items
rocksdb.rocksdb_iter_next(iter)
continue
}
append(&items, item)
count += 1
// Move to next
rocksdb.rocksdb_iter_next(iter)
}
// Convert to slice (owned by caller's allocator)
result_items := make([]Item, len(items), engine.allocator)
copy(result_items, items[:])
return Scan_Result{
items = result_items,
last_evaluated_key = last_key,
}, .None
}
// Helper to check if a byte slice has a prefix
has_prefix :: proc(data: []byte, prefix: []byte) -> bool {
if len(data) < len(prefix) {
return false
}
for i in 0..<len(prefix) {
if data[i] != prefix[i] {
return false
}
}
return true
}
// List tables (simplified - returns empty list for now) // List tables (simplified - returns empty list for now)
list_tables :: proc(engine: ^Storage_Engine) -> []string { list_tables :: proc(engine: ^Storage_Engine) -> []string {
// TODO: Implement by iterating over meta keys // TODO: Implement by iterating over meta keys

View File

@@ -398,11 +398,64 @@ handle_query :: proc(engine: ^dynamodb.Storage_Engine, request: ^HTTP_Request, r
} }
handle_scan :: proc(engine: ^dynamodb.Storage_Engine, request: ^HTTP_Request, response: ^HTTP_Response) { handle_scan :: proc(engine: ^dynamodb.Storage_Engine, request: ^HTTP_Request, response: ^HTTP_Response) {
_ = engine table_name, ok := dynamodb.parse_table_name(request.body)
_ = request if !ok {
make_error_response(response, .ValidationException, "Invalid request or missing TableName")
return
}
// TODO: Implement scan operation in storage.odin // Parse Limit (default to 100 if not specified)
make_error_response(response, .ValidationException, "Scan operation not yet implemented") limit := dynamodb.parse_limit(request.body)
if limit == 0 {
limit = 100
}
// Parse ExclusiveStartKey if present
// For now, we'll implement basic scan without ExclusiveStartKey parsing
// TODO: Parse ExclusiveStartKey from request body and convert to binary key
exclusive_start_key: Maybe([]byte) = nil
// Perform scan
result, err := dynamodb.scan(engine, table_name, exclusive_start_key, limit)
if err != .None {
#partial switch err {
case .Table_Not_Found:
make_error_response(response, .ResourceNotFoundException, "Table not found")
case:
make_error_response(response, .InternalServerError, "Failed to scan table")
}
return
}
defer dynamodb.scan_result_destroy(&result)
// Build response
builder := strings.builder_make()
strings.write_string(&builder, `{"Items":[`)
for item, i in result.items {
if i > 0 do strings.write_string(&builder, ",")
item_json := dynamodb.serialize_item(item)
strings.write_string(&builder, item_json)
}
strings.write_string(&builder, `],"Count":`)
fmt.sbprintf(&builder, "%d", len(result.items))
strings.write_string(&builder, `,"ScannedCount":`)
fmt.sbprintf(&builder, "%d", len(result.items))
// Add LastEvaluatedKey if present (pagination)
if last_key, has_last := result.last_evaluated_key.?; has_last {
// TODO: Convert binary key back to DynamoDB JSON format
// For now, we'll just include it as base64 (not DynamoDB-compatible yet)
_ = last_key
// When fully implemented, this should decode the key and serialize as:
// ,"LastEvaluatedKey":{"pk":{"S":"value"},"sk":{"N":"123"}}
}
strings.write_string(&builder, "}")
resp_body := strings.to_string(builder)
response_set_body(response, transmute([]byte)resp_body)
} }
// ============================================================================ // ============================================================================