feat(extensions): add the PHP extension generator (#1649)

* feat(extensions): add the PHP extension generator

* unexport many types

* unexport more symbols

* cleanup some tests

* unexport more symbols

* fix

* revert types files

* revert

* add better validation and fix templates

* remove GoStringCopy

* small fixes

---------

Co-authored-by: Kévin Dunglas <kevin@dunglas.fr>

Author: alexandre-daubois

caddy/extinit.go

@@ -0,0 +1,53 @@
+package caddy
+
+import (
+	"errors"
+	"github.com/dunglas/frankenphp/internal/extgen"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+
+	caddycmd "github.com/caddyserver/caddy/v2/cmd"
+	"github.com/spf13/cobra"
+)
+
+func init() {
+	caddycmd.RegisterCommand(caddycmd.Command{
+		Name:  "extension-init",
+		Usage: "go_extension.go [--verbose]",
+		Short: "(Experimental) Initializes a PHP extension from a Go file",
+		Long: `
+Initializes a PHP extension from a Go file. This command generates the necessary C files for the extension, including the header and source files, as well as the arginfo file.`,
+		CobraFunc: func(cmd *cobra.Command) {
+			cmd.Flags().BoolP("debug", "v", false, "Enable verbose debug logs")
+
+			cmd.RunE = caddycmd.WrapCommandFuncForCobra(cmdInitExtension)
+		},
+	})
+}
+
+func cmdInitExtension(fs caddycmd.Flags) (int, error) {
+	if len(os.Args) < 3 {
+		return 1, errors.New("the path to the Go source is required")
+	}
+
+	sourceFile := os.Args[2]
+
+	baseName := strings.TrimSuffix(filepath.Base(sourceFile), ".go")
+
+	baseName = extgen.SanitizePackageName(baseName)
+
+	sourceDir := filepath.Dir(sourceFile)
+	buildDir := filepath.Join(sourceDir, "build")
+
+	generator := extgen.Generator{BaseName: baseName, SourceFile: sourceFile, BuildDir: buildDir}
+
+	if err := generator.Generate(); err != nil {
+		return 1, err
+	}
+
+	log.Printf("PHP extension %q initialized successfully in %q", baseName, generator.BuildDir)
+
+	return 0, nil
+}

internal/extgen/arginfo.go

@@ -0,0 +1,50 @@
+package extgen
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+)
+
+type arginfoGenerator struct {
+	generator *Generator
+}
+
+func (ag *arginfoGenerator) generate() error {
+	genStubPath := os.Getenv("GEN_STUB_SCRIPT")
+	if genStubPath == "" {
+		genStubPath = "/usr/local/src/php/build/gen_stub.php"
+	}
+
+	if _, err := os.Stat(genStubPath); err != nil {
+		return fmt.Errorf(`the PHP "gen_stub.php" file couldn't be found under %q, you can set the "GEN_STUB_SCRIPT" environement variable to set a custom location`, genStubPath)
+	}
+
+	stubFile := ag.generator.BaseName + ".stub.php"
+	cmd := exec.Command("php", genStubPath, filepath.Join(ag.generator.BuildDir, stubFile))
+
+	if err := cmd.Run(); err != nil {
+		return fmt.Errorf("running gen_stub script: %w", err)
+	}
+
+	return ag.fixArginfoFile(stubFile)
+}
+
+func (ag *arginfoGenerator) fixArginfoFile(stubFile string) error {
+	arginfoFile := strings.TrimSuffix(stubFile, ".stub.php") + "_arginfo.h"
+	arginfoPath := filepath.Join(ag.generator.BuildDir, arginfoFile)
+
+	content, err := ReadFile(arginfoPath)
+	if err != nil {
+		return fmt.Errorf("reading arginfo file: %w", err)
+	}
+
+	// TODO: Fix the zend_register_internal_class_with_flags issue
+	fixedContent := strings.ReplaceAll(content,
+		"zend_register_internal_class_with_flags(&ce, NULL, 0)",
+		"zend_register_internal_class(&ce)")
+
+	return WriteFile(arginfoPath, fixedContent)
+}

internal/extgen/cfile.go

@@ -0,0 +1,78 @@
+package extgen
+
+import (
+	"bytes"
+	_ "embed"
+	"path/filepath"
+	"strings"
+	"text/template"
+)
+
+//go:embed templates/extension.c.tpl
+var cFileContent string
+
+type cFileGenerator struct {
+	generator *Generator
+}
+
+type cTemplateData struct {
+	BaseName  string
+	Functions []phpFunction
+	Classes   []phpClass
+	Constants []phpConstant
+	Version   string
+}
+
+func (cg *cFileGenerator) generate() error {
+	filename := filepath.Join(cg.generator.BuildDir, cg.generator.BaseName+".c")
+	content, err := cg.buildContent()
+	if err != nil {
+		return err
+	}
+	return WriteFile(filename, content)
+}
+
+func (cg *cFileGenerator) buildContent() (string, error) {
+	var builder strings.Builder
+
+	templateContent, err := cg.getTemplateContent()
+	if err != nil {
+		return "", err
+	}
+	builder.WriteString(templateContent)
+
+	for _, fn := range cg.generator.Functions {
+		fnGen := PHPFuncGenerator{paramParser: &ParameterParser{}}
+		builder.WriteString(fnGen.generate(fn))
+	}
+
+	return builder.String(), nil
+}
+
+func (cg *cFileGenerator) getTemplateContent() (string, error) {
+	tmpl, err := template.New("cfile").Funcs(template.FuncMap{
+		"inc": func(i int) int {
+			return i + 1
+		},
+	}).Parse(cFileContent)
+
+	if err != nil {
+		return "", err
+	}
+
+	data := cTemplateData{
+		BaseName:  cg.generator.BaseName,
+		Functions: cg.generator.Functions,
+		Classes:   cg.generator.Classes,
+		Constants: cg.generator.Constants,
+		Version:   "1.0.0",
+	}
+
+	var buf bytes.Buffer
+	err = tmpl.Execute(&buf, data)
+	if err != nil {
+		return "", err
+	}
+
+	return buf.String(), nil
+}