pluginsdk/plugin/wasmguest/caps/bridge.go

package caps

import (
	"context"

	abiv1 "git.dev.alexdunmow.com/block/pluginsdk/abi/v1"
	"git.dev.alexdunmow.com/block/pluginsdk/plugin"
)

// bridgeStub implements plugin.PluginBridge over bridge.* capability calls.
//
// The bridge shares in-process Go values today; across sandboxes only the
// registration/lookup *surface* serializes — the service value itself cannot
// cross. RegisterService therefore forwards only plugin/service names to the
// host AND records the value locally so this plugin's own services are
// dispatchable via HOOK_BRIDGE_CALL; GetService returns nil for remote
// services (availability is checked but a typed value cannot be reconstructed
// guest-side). Cross-plugin calls use Invoke (bridge.invoke) with opaque
// payloads instead.
//
// Instances are single-threaded, so the plain map needs no locking; register
// bridge services in Register (every pooled instance runs it), not Load
// (which fires on one instance only) — see core/docs/wasm-abi.md
// §"Per-instance state".
type bridgeStub struct {
	base
	services map[string]any // serviceName → registered value (this plugin's own)
}

var _ plugin.PluginBridge = (*bridgeStub)(nil)

// RegisterService has no error channel; a transport failure is dropped.
func (s *bridgeStub) RegisterService(pluginName, serviceName string, service any) {
	if s.services == nil {
		s.services = make(map[string]any)
	}
	s.services[serviceName] = service
	req := &abiv1.BridgeRegisterServiceRequest{PluginName: pluginName, ServiceName: serviceName}
	_ = s.invoke(context.Background(), "register_service", req, &abiv1.BridgeRegisterServiceResponse{})
}

// GetService reports availability host-side but cannot return the concrete Go
// value across the sandbox boundary, so it always returns nil for remote
// services. Callers using plugin.GetServiceAs correctly observe (zero, false);
// cross-plugin calls go through Invoke.
func (s *bridgeStub) GetService(pluginName, serviceName string) any {
	req := &abiv1.BridgeGetServiceRequest{PluginName: pluginName, ServiceName: serviceName}
	_ = s.invoke(context.Background(), "get_service", req, &abiv1.BridgeGetServiceResponse{})
	return nil
}

// Invoke calls a method on another plugin's registered bridge service with an
// opaque payload (bridge.invoke; the provider answers via HOOK_BRIDGE_CALL or
// its in-process plugin.BridgeInvokable).
func (s *bridgeStub) Invoke(ctx context.Context, pluginName, serviceName, method string, payload []byte) ([]byte, error) {
	req := &abiv1.BridgeInvokeRequest{
		PluginName:  pluginName,
		ServiceName: serviceName,
		Method:      method,
		Payload:     payload,
	}
	resp := &abiv1.BridgeInvokeResponse{}
	if err := s.invoke(ctx, "invoke", req, resp); err != nil {
		return nil, err
	}
	return resp.GetPayload(), nil
}

// Service returns this plugin's own registered service value, for
// HOOK_BRIDGE_CALL dispatch by the wasm shim.
func (s *bridgeStub) Service(serviceName string) (any, bool) {
	v, ok := s.services[serviceName]
	return v, ok
}