plugins: Introduce generated, static core plugin registry (#54118)

* Refactor towards template/codegen framework * Add templates for plugin gen * Add Go codegen for plugins; overhaul framework, too * Add new codegen output; assorted framework fixes * Regenerate after merge * Remove accidental commit file, update templates * Export the pfs.Tree loader from plugin types * Print details from cuetsy errors * Generate loaders for all plugins and list in registry * Use pfs_gen.go over lineage_gen.go * Un-un-ignore main file * Introduce simple List static registry for plugins * Last tweaks to codegen * remove unused tvars * Ensure loop-local instances for both vars * Generate pfs parsing in-place in registry * Stop generating pfs_gen.go * Move Tree into pfs, rename subdir * Change package name to match dir * Ignore gocyclo on HTTPServer.getNavTree
2022-09-14 10:15:09 -04:00
parent c69a37f8c2
commit ced53a8dc2
36 changed files with 1114 additions and 324 deletions
@@ -0,0 +1,67 @@
+package codegen
+
+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/format"
+	"go/parser"
+	"go/token"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"golang.org/x/tools/imports"
+)
+
+type genGoFile struct {
+	path   string
+	walker ast.Visitor
+	in     []byte
+}
+
+func postprocessGoFile(cfg genGoFile) ([]byte, error) {
+	fname := filepath.Base(cfg.path)
+	buf := new(bytes.Buffer)
+	fset := token.NewFileSet()
+	gf, err := parser.ParseFile(fset, fname, string(cfg.in), parser.ParseComments)
+	if err != nil {
+		return nil, fmt.Errorf("error parsing generated file: %w", err)
+	}
+
+	if cfg.walker != nil {
+		ast.Walk(cfg.walker, gf)
+
+		err = format.Node(buf, fset, gf)
+		if err != nil {
+			return nil, fmt.Errorf("error formatting Go AST: %w", err)
+		}
+	} else {
+		buf = bytes.NewBuffer(cfg.in)
+	}
+
+	byt, err := imports.Process(fname, buf.Bytes(), nil)
+	if err != nil {
+		return nil, fmt.Errorf("goimports processing failed: %w", err)
+	}
+
+	// Compare imports before and after; warn about performance if some were added
+	gfa, _ := parser.ParseFile(fset, fname, string(byt), parser.ParseComments)
+	imap := make(map[string]bool)
+	for _, im := range gf.Imports {
+		imap[im.Path.Value] = true
+	}
+	var added []string
+	for _, im := range gfa.Imports {
+		if !imap[im.Path.Value] {
+			added = append(added, im.Path.Value)
+		}
+	}
+
+	if len(added) != 0 {
+		// TODO improve the guidance in this error if/when we better abstract over imports to generate
+		fmt.Fprintf(os.Stderr, "The following imports were added by goimports while generating %s: \n\t%s\nRelying on goimports to find imports significantly slows down code generation. Consider adding these to the relevant template.\n", cfg.path, strings.Join(added, "\n\t"))
+	}
+
+	return byt, nil
+}