wasm: split out host-specific bits

Signed-off-by: Xe Iaso <me@xeiaso.net>

1 files changed, 41 insertions, 0 deletions

diff --git a/wasm/wasm_host.go b/wasm/wasm_host.go
new file mode 100644
index 0000000..64b8654
--- /dev/null
+++ b/wasm/wasm_host.go
@@ -0,0 +1,41 @@
+//go:build !wasip1
+
+package wasm
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/tetratelabs/wazero/api"
+)
+
+func (value String) Load(module api.Module) string {
+	return string(value.LoadBytes(module))
+}
+
+func (value String) LoadBytes(module api.Module) []byte {
+	data, ok := module.Memory().Read(uint32(value>>32), uint32(value))
+	if !ok {
+		panic("memory read out of bounds")
+	}
+	return data
+}
+
+func (buffer Buffer) Load(module api.Module) []byte {
+	data, ok := module.Memory().Read(buffer.Address(), buffer.Length())
+	if !ok {
+		panic("memory read out of bounds")
+	}
+	return data
+}
+
+func Store(ctx context.Context, module api.Module, data []byte) (Buffer, error) {
+	results, err := module.ExportedFunction("malloc").Call(ctx, uint64(len(data)))
+	if err != nil {
+		return 0, fmt.Errorf("wasm: failed to call malloc: %w", err)
+	}
+
+	buffer := Buffer(results[0])
+	module.Memory().Write(buffer.Address(), data)
+	return buffer, nil
+}