Add Vat init transformer

vendor/github.com/tinylib/msgp/parse/directives.go

@@ -0,0 +1,117 @@
+package parse
+
+import (
+	"fmt"
+	"github.com/tinylib/msgp/gen"
+	"go/ast"
+	"strings"
+)
+
+const linePrefix = "//msgp:"
+
+// func(args, fileset)
+type directive func([]string, *FileSet) error
+
+// func(passName, args, printer)
+type passDirective func(gen.Method, []string, *gen.Printer) error
+
+// map of all recognized directives
+//
+// to add a directive, define a func([]string, *FileSet) error
+// and then add it to this list.
+var directives = map[string]directive{
+	"shim":   applyShim,
+	"ignore": ignore,
+	"tuple":  astuple,
+}
+
+var passDirectives = map[string]passDirective{
+	"ignore": passignore,
+}
+
+func passignore(m gen.Method, text []string, p *gen.Printer) error {
+	pushstate(m.String())
+	for _, a := range text {
+		p.ApplyDirective(m, gen.IgnoreTypename(a))
+		infof("ignoring %s\n", a)
+	}
+	popstate()
+	return nil
+}
+
+// find all comment lines that begin with //msgp:
+func yieldComments(c []*ast.CommentGroup) []string {
+	var out []string
+	for _, cg := range c {
+		for _, line := range cg.List {
+			if strings.HasPrefix(line.Text, linePrefix) {
+				out = append(out, strings.TrimPrefix(line.Text, linePrefix))
+			}
+		}
+	}
+	return out
+}
+
+//msgp:shim {Type} as:{Newtype} using:{toFunc/fromFunc}
+func applyShim(text []string, f *FileSet) error {
+	if len(text) != 4 {
+		return fmt.Errorf("shim directive should have 3 arguments; found %d", len(text)-1)
+	}
+
+	name := text[1]
+	be := gen.Ident(strings.TrimPrefix(strings.TrimSpace(text[2]), "as:")) // parse as::{base}
+	if name[0] == '*' {
+		name = name[1:]
+		be.Needsref(true)
+	}
+	be.Alias(name)
+
+	usestr := strings.TrimPrefix(strings.TrimSpace(text[3]), "using:") // parse using::{method/method}
+
+	methods := strings.Split(usestr, "/")
+	if len(methods) != 2 {
+		return fmt.Errorf("expected 2 using::{} methods; found %d (%q)", len(methods), text[3])
+	}
+
+	be.ShimToBase = methods[0]
+	be.ShimFromBase = methods[1]
+
+	infof("%s -> %s\n", name, be.Value.String())
+	f.findShim(name, be)
+
+	return nil
+}
+
+//msgp:ignore {TypeA} {TypeB}...
+func ignore(text []string, f *FileSet) error {
+	if len(text) < 2 {
+		return nil
+	}
+	for _, item := range text[1:] {
+		name := strings.TrimSpace(item)
+		if _, ok := f.Identities[name]; ok {
+			delete(f.Identities, name)
+			infof("ignoring %s\n", name)
+		}
+	}
+	return nil
+}
+
+//msgp:tuple {TypeA} {TypeB}...
+func astuple(text []string, f *FileSet) error {
+	if len(text) < 2 {
+		return nil
+	}
+	for _, item := range text[1:] {
+		name := strings.TrimSpace(item)
+		if el, ok := f.Identities[name]; ok {
+			if st, ok := el.(*gen.Struct); ok {
+				st.AsTuple = true
+				infoln(name)
+			} else {
+				warnf("%s: only structs can be tuples\n", name)
+			}
+		}
+	}
+	return nil
+}