cmd/hlang: move run to its own package

Signed-off-by: Xe <me@christine.website>

3 files changed, 84 insertions, 0 deletions

diff --git a/cmd/hlang/run/run.go b/cmd/hlang/run/run.go
new file mode 100644
index 0000000..5526df4
--- /dev/null
+++ b/cmd/hlang/run/run.go
@@ -0,0 +1,67 @@
+package run
+
+import (
+	"context"
+	"time"
+
+	"github.com/tetratelabs/wazero"
+	"github.com/tetratelabs/wazero/api"
+)
+
+type Process struct {
+	Output []byte
+}
+
+func (p *Process) Putchar(ctx context.Context, stack []uint64) {
+	x := api.DecodeI32(stack[0])
+	p.putchar(x)
+}
+
+func (p *Process) putchar(char int32) {
+	p.Output = append(p.Output, byte(char))
+}
+
+func Run(bin []byte) (*ExecResult, error) {
+	ctx := context.Background()
+	r := wazero.NewRuntime(ctx)
+	defer r.Close(ctx)
+
+	p := &Process{}
+
+	env, err := r.NewHostModuleBuilder("h").
+		NewFunctionBuilder().
+		WithGoFunction(api.GoFunc(p.Putchar), []api.ValueType{api.ValueTypeI32}, nil).
+		Export("h").
+		Instantiate(ctx, r)
+	if err != nil {
+		return nil, err
+	}
+	defer env.Close(ctx)
+
+	code, err := r.CompileModule(ctx, bin)
+	if err != nil {
+		return nil, err
+	}
+
+	mod, err := r.InstantiateModule(ctx, code, wazero.NewModuleConfig())
+	if err != nil {
+		return nil, err
+	}
+	defer mod.Close(ctx)
+
+	t0 := time.Now()
+	if _, err = mod.ExportedFunction("h").Call(ctx); err != nil {
+		return nil, err
+	}
+	runTime := time.Since(t0)
+
+	return &ExecResult{
+		Output:   string(p.Output),
+		ExecTime: runTime,
+	}, nil
+}
+
+type ExecResult struct {
+	Output   string        `json:"out"`
+	ExecTime time.Duration `json:"exec_duration"`
+}
diff --git a/cmd/hlang/run/run_test.go b/cmd/hlang/run/run_test.go
new file mode 100644
index 0000000..5e2fdae
--- /dev/null
+++ b/cmd/hlang/run/run_test.go
@@ -0,0 +1,17 @@
+package run
+
+import (
+	_ "embed"
+	"testing"
+)
+
+//go:embed testdata/h.wasm
+var bin []byte
+
+func BenchmarkRun(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		if _, err := Run(bin); err != nil {
+			b.Fatal(err)
+		}
+	}
+}
diff --git a/cmd/hlang/run/testdata/h.wasm b/cmd/hlang/run/testdata/h.wasm
new file mode 100644
index 0000000..6a0d90d
--- /dev/null
+++ b/cmd/hlang/run/testdata/h.wasm