1package binary
 2
 3import (
 4	"bytes"
 5	"fmt"
 6
 7	"github.com/tetratelabs/wazero/api"
 8	"github.com/tetratelabs/wazero/experimental"
 9	"github.com/tetratelabs/wazero/internal/wasm"
10)
11
12// decodeMemory returns the api.Memory decoded with the WebAssembly 1.0 (20191205) Binary Format.
13//
14// See https://www.w3.org/TR/2019/REC-wasm-core-1-20191205/#binary-memory
15func decodeMemory(
16	r *bytes.Reader,
17	enabledFeatures api.CoreFeatures,
18	memorySizer func(minPages uint32, maxPages *uint32) (min, capacity, max uint32),
19	memoryLimitPages uint32,
20) (*wasm.Memory, error) {
21	min, maxP, shared, err := decodeLimitsType(r)
22	if err != nil {
23		return nil, err
24	}
25
26	if shared {
27		if !enabledFeatures.IsEnabled(experimental.CoreFeaturesThreads) {
28			return nil, fmt.Errorf("shared memory requested but threads feature not enabled")
29		}
30
31		// This restriction may be lifted in the future.
32		// https://webassembly.github.io/threads/core/binary/types.html#memory-types
33		if maxP == nil {
34			return nil, fmt.Errorf("shared memory requires a maximum size to be specified")
35		}
36	}
37
38	min, capacity, max := memorySizer(min, maxP)
39	mem := &wasm.Memory{Min: min, Cap: capacity, Max: max, IsMaxEncoded: maxP != nil, IsShared: shared}
40
41	return mem, mem.Validate(memoryLimitPages)
42}