feat: spec2go — generate service name constants and Get* accessor files

Author: xaionaro@dx.center

tools/cmd/spec2go/main.go

@@ -851,6 +851,183 @@ func newRegistryResolver(
 	return r
 }
 
+// generateServiceNamesFile generates servicemanager/service_names_gen.go from
+// the Services field of the servicemanager package spec. Each ServiceMapping
+// produces a typed constant: ConstantName (SCREAMING_SNAKE) is converted to
+// PascalCase, and the value is the service_name string.
+func generateServiceNamesFile(
+	specs map[string]*spec.PackageSpec,
+	outputDir string,
+) error {
+	smSpec := specs["servicemanager"]
+	if smSpec == nil || len(smSpec.Services) == 0 {
+		return nil
+	}
+
+	// Build sorted constant entries.
+	type constEntry struct {
+		GoName      string
+		ServiceName string
+	}
+
+	entries := make([]constEntry, 0, len(smSpec.Services))
+	for _, svc := range smSpec.Services {
+		goName := codegen.ScreamingSnakeToPascal(svc.ConstantName)
+		entries = append(entries, constEntry{
+			GoName:      goName,
+			ServiceName: svc.ServiceName,
+		})
+	}
+	sort.Slice(entries, func(i, j int) bool {
+		return entries[i].GoName < entries[j].GoName
+	})
+
+	// Find the longest GoName for column alignment.
+	maxLen := 0
+	for _, e := range entries {
+		if len(e.GoName) > maxLen {
+			maxLen = len(e.GoName)
+		}
+	}
+
+	var buf bytes.Buffer
+	buf.WriteString("// Code generated by spec2go. DO NOT EDIT.\n\n")
+	buf.WriteString("package servicemanager\n\n")
+	buf.WriteString("// Service name constants extracted from android.content.Context.\n")
+	buf.WriteString("const (\n")
+
+	for _, e := range entries {
+		padding := strings.Repeat(" ", maxLen-len(e.GoName))
+		fmt.Fprintf(&buf, "\t%s%s ServiceName = %q\n", e.GoName, padding, e.ServiceName)
+	}
+
+	buf.WriteString(")\n")
+
+	formatted, err := format.Source(buf.Bytes())
+	if err != nil {
+		return fmt.Errorf("formatting service names: %w\n\nRaw source:\n%s", err, buf.String())
+	}
+
+	outPath := filepath.Join(outputDir, "servicemanager", "service_names_gen.go")
+	if err := os.MkdirAll(filepath.Dir(outPath), 0o755); err != nil {
+		return fmt.Errorf("creating directory: %w", err)
+	}
+	if err := os.WriteFile(outPath, formatted, 0o644); err != nil {
+		return fmt.Errorf("writing %s: %w", outPath, err)
+	}
+
+	fmt.Fprintf(os.Stderr, "Wrote %s (%d constants)\n", outPath, len(entries))
+	return nil
+}
+
+// generateAccessorFiles generates get_*.go files for services whose AIDL
+// interface has a generated proxy in the output directory. Each file contains
+// a GetXxxManager function that calls ServiceManager.GetService and wraps
+// the result in the typed proxy constructor.
+func generateAccessorFiles(
+	specs map[string]*spec.PackageSpec,
+	outputDir string,
+) error {
+	smSpec := specs["servicemanager"]
+	if smSpec == nil || len(smSpec.Services) == 0 {
+		return nil
+	}
+
+	// Build a descriptor -> InterfaceSpec index across all specs so we can
+	// look up the interface definition for each service's descriptor.
+	type ifaceInfo struct {
+		GoPackage     string
+		InterfaceName string
+	}
+	descriptorIndex := map[string]ifaceInfo{}
+	for _, ps := range specs {
+		for _, iface := range ps.Interfaces {
+			desc := ps.AIDLPackage + "." + iface.Name
+			descriptorIndex[desc] = ifaceInfo{
+				GoPackage:     ps.GoPackage,
+				InterfaceName: iface.Name,
+			}
+		}
+	}
+
+	count := 0
+	for _, svc := range smSpec.Services {
+		info, ok := descriptorIndex[svc.Descriptor]
+		if !ok {
+			continue
+		}
+
+		interfaceGoName := codegen.AIDLToGoName(info.InterfaceName)
+		proxyName := deriveProxyName(interfaceGoName)
+		constructorName := "New" + proxyName
+
+		// Verify the proxy constructor exists in the output directory by
+		// checking that the generated interface file is present.
+		goFileName := codegen.AIDLToGoFileName(info.InterfaceName)
+		ifaceFilePath := filepath.Join(outputDir, info.GoPackage, goFileName)
+		if _, err := os.Stat(ifaceFilePath); err != nil {
+			continue
+		}
+
+		// Determine the Go package name (last segment of the package path).
+		goPkg := filepath.Base(info.GoPackage)
+
+		// Build the constant name for the servicemanager constant.
+		constName := codegen.ScreamingSnakeToPascal(svc.ConstantName)
+
+		// The base name without Proxy suffix is used for the Get function.
+		baseName := interfaceGoName
+		if strings.HasPrefix(interfaceGoName, "I") && len(interfaceGoName) > 1 {
+			baseName = interfaceGoName[1:]
+		}
+		funcName := "Get" + baseName
+
+		var buf bytes.Buffer
+		buf.WriteString("// Code generated by spec2go. DO NOT EDIT.\n\n")
+		fmt.Fprintf(&buf, "package %s\n\n", goPkg)
+		buf.WriteString("import (\n")
+		buf.WriteString("\t\"context\"\n")
+		buf.WriteString("\t\"fmt\"\n\n")
+		buf.WriteString("\t\"github.com/xaionaro-go/binder/servicemanager\"\n")
+		buf.WriteString(")\n\n")
+		fmt.Fprintf(&buf, "// %s retrieves the %s service and returns a typed proxy.\n", funcName, constName)
+		fmt.Fprintf(&buf, "func %s(\n", funcName)
+		buf.WriteString("\tctx context.Context,\n")
+		buf.WriteString("\tsm *servicemanager.ServiceManager,\n")
+		fmt.Fprintf(&buf, ") (*%s, error) {\n", proxyName)
+		fmt.Fprintf(&buf, "\tsvc, err := sm.GetService(ctx, servicemanager.%s)\n", constName)
+		buf.WriteString("\tif err != nil {\n")
+		fmt.Fprintf(&buf, "\t\treturn nil, fmt.Errorf(\"%s: %%w\", err)\n", funcName)
+		buf.WriteString("\t}\n")
+		fmt.Fprintf(&buf, "\treturn %s(svc), nil\n", constructorName)
+		buf.WriteString("}\n")
+
+		formatted, fmtErr := format.Source(buf.Bytes())
+		if fmtErr != nil {
+			return fmt.Errorf("formatting accessor for %s: %w\n\nRaw source:\n%s", svc.ServiceName, fmtErr, buf.String())
+		}
+
+		outPath := filepath.Join(outputDir, info.GoPackage, "get_"+svc.ServiceName+".go")
+		if err := os.WriteFile(outPath, formatted, 0o644); err != nil {
+			return fmt.Errorf("writing %s: %w", outPath, err)
+		}
+		count++
+	}
+
+	fmt.Fprintf(os.Stderr, "Generated %d accessor files\n", count)
+	return nil
+}
+
+// deriveProxyName derives a proxy struct name from an interface name.
+// IFoo -> FooProxy, Foo -> FooProxy. This mirrors the codegen convention.
+func deriveProxyName(interfaceName string) string {
+	base := interfaceName
+	if strings.HasPrefix(interfaceName, "I") && len(interfaceName) > 1 {
+		base = interfaceName[1:]
+	}
+	return base + "Proxy"
+}
+
 // generateCodesFile builds codes_gen.go from version_codes embedded in
 // interface specs.
 func generateCodesFile(