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wire.go
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wire.go
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// Copyright 2018 The Wire Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Package wire provides compile-time dependency injection logic as a
// Go library.
package wire
import (
"bytes"
"context"
"errors"
"fmt"
"go/ast"
"go/format"
"go/printer"
"go/token"
"go/types"
"io/ioutil"
"path/filepath"
"sort"
"strconv"
"strings"
"unicode"
"unicode/utf8"
"golang.org/x/tools/go/ast/astutil"
"golang.org/x/tools/go/packages"
)
// GenerateResult stores the result for a package from a call to Generate.
type GenerateResult struct {
// PkgPath is the package's PkgPath.
PkgPath string
// OutputPath is the path where the generated output should be written.
// May be empty if there were errors.
OutputPath string
// Content is the gofmt'd source code that was generated. May be nil if
// there were errors during generation.
Content []byte
// Errs is a slice of errors identified during generation.
Errs []error
}
// Commit writes the generated file to disk.
func (gen GenerateResult) Commit() error {
if len(gen.Content) == 0 {
return nil
}
return ioutil.WriteFile(gen.OutputPath, gen.Content, 0666)
}
// GenerateOptions holds options for Generate.
type GenerateOptions struct {
// Header will be inserted at the start of each generated file.
Header []byte
PrefixOutputFile string
}
// Generate performs dependency injection for the packages that match the given
// patterns, return a GenerateResult for each package. The package pattern is
// defined by the underlying build system. For the go tool, this is described at
// https://golang.org/cmd/go/#hdr-Package_lists_and_patterns
//
// wd is the working directory and env is the set of environment
// variables to use when loading the package specified by pkgPattern. If
// env is nil or empty, it is interpreted as an empty set of variables.
// In case of duplicate environment variables, the last one in the list
// takes precedence.
//
// Generate may return one or more errors if it failed to load the packages.
func Generate(ctx context.Context, wd string, env []string, patterns []string, opts *GenerateOptions) ([]GenerateResult, []error) {
if opts == nil {
opts = &GenerateOptions{}
}
pkgs, errs := load(ctx, wd, env, patterns)
if len(errs) > 0 {
return nil, errs
}
generated := make([]GenerateResult, len(pkgs))
for i, pkg := range pkgs {
generated[i].PkgPath = pkg.PkgPath
outDir, err := detectOutputDir(pkg.GoFiles)
if err != nil {
generated[i].Errs = append(generated[i].Errs, err)
continue
}
generated[i].OutputPath = filepath.Join(outDir, opts.PrefixOutputFile+"wire_gen.go")
g := newGen(pkg)
injectorFiles, errs := generateInjectors(g, pkg)
if len(errs) > 0 {
generated[i].Errs = errs
continue
}
copyNonInjectorDecls(g, injectorFiles, pkg.TypesInfo)
goSrc := g.frame()
if len(opts.Header) > 0 {
goSrc = append(opts.Header, goSrc...)
}
fmtSrc, err := format.Source(goSrc)
if err != nil {
// This is likely a bug from a poorly generated source file.
// Add an error but also the unformatted source.
generated[i].Errs = append(generated[i].Errs, err)
} else {
goSrc = fmtSrc
}
generated[i].Content = goSrc
}
return generated, nil
}
func detectOutputDir(paths []string) (string, error) {
if len(paths) == 0 {
return "", errors.New("no files to derive output directory from")
}
dir := filepath.Dir(paths[0])
for _, p := range paths[1:] {
if dir2 := filepath.Dir(p); dir2 != dir {
return "", fmt.Errorf("found conflicting directories %q and %q", dir, dir2)
}
}
return dir, nil
}
// generateInjectors generates the injectors for a given package.
func generateInjectors(g *gen, pkg *packages.Package) (injectorFiles []*ast.File, _ []error) {
oc := newObjectCache([]*packages.Package{pkg})
injectorFiles = make([]*ast.File, 0, len(pkg.Syntax))
ec := new(errorCollector)
for _, f := range pkg.Syntax {
for _, decl := range f.Decls {
fn, ok := decl.(*ast.FuncDecl)
if !ok {
continue
}
buildCall, err := findInjectorBuild(pkg.TypesInfo, fn)
if err != nil {
ec.add(err)
continue
}
if buildCall == nil {
continue
}
if len(injectorFiles) == 0 || injectorFiles[len(injectorFiles)-1] != f {
// This is the first injector generated for this file.
// Write a file header.
name := filepath.Base(g.pkg.Fset.File(f.Pos()).Name())
g.p("// Injectors from %s:\n\n", name)
injectorFiles = append(injectorFiles, f)
}
sig := pkg.TypesInfo.ObjectOf(fn.Name).Type().(*types.Signature)
ins, _, err := injectorFuncSignature(sig)
if err != nil {
if w, ok := err.(*wireErr); ok {
ec.add(notePosition(w.position, fmt.Errorf("inject %s: %v", fn.Name.Name, w.error)))
} else {
ec.add(notePosition(g.pkg.Fset.Position(fn.Pos()), fmt.Errorf("inject %s: %v", fn.Name.Name, err)))
}
continue
}
injectorArgs := &InjectorArgs{
Name: fn.Name.Name,
Tuple: ins,
Pos: fn.Pos(),
}
set, errs := oc.processNewSet(pkg.TypesInfo, pkg.PkgPath, buildCall, injectorArgs, "")
if len(errs) > 0 {
ec.add(notePositionAll(g.pkg.Fset.Position(fn.Pos()), errs)...)
continue
}
if errs := g.inject(fn.Pos(), fn.Name.Name, sig, set); len(errs) > 0 {
ec.add(errs...)
continue
}
}
for _, impt := range f.Imports {
if impt.Name != nil && impt.Name.Name == "_" {
g.anonImports[impt.Path.Value] = true
}
}
}
if len(ec.errors) > 0 {
return nil, ec.errors
}
return injectorFiles, nil
}
// copyNonInjectorDecls copies any non-injector declarations from the
// given files into the generated output.
func copyNonInjectorDecls(g *gen, files []*ast.File, info *types.Info) {
for _, f := range files {
name := filepath.Base(g.pkg.Fset.File(f.Pos()).Name())
first := true
for _, decl := range f.Decls {
switch decl := decl.(type) {
case *ast.FuncDecl:
// OK to ignore error, as any error cases should already have
// been filtered out.
if buildCall, _ := findInjectorBuild(info, decl); buildCall != nil {
continue
}
case *ast.GenDecl:
if decl.Tok == token.IMPORT {
continue
}
default:
continue
}
if first {
g.p("// %s:\n\n", name)
first = false
}
// TODO(light): Add line number at top of each declaration.
g.writeAST(info, decl)
g.p("\n\n")
}
}
}
// importInfo holds info about an import.
type importInfo struct {
// name is the identifier that is used in the generated source.
name string
// differs is true if the import is given an identifier that does not
// match the package's identifier.
differs bool
}
// gen is the file-wide generator state.
type gen struct {
pkg *packages.Package
buf bytes.Buffer
imports map[string]importInfo
anonImports map[string]bool
values map[ast.Expr]string
}
func newGen(pkg *packages.Package) *gen {
return &gen{
pkg: pkg,
anonImports: make(map[string]bool),
imports: make(map[string]importInfo),
values: make(map[ast.Expr]string),
}
}
// frame bakes the built up source body into an unformatted Go source file.
func (g *gen) frame() []byte {
if g.buf.Len() == 0 {
return nil
}
var buf bytes.Buffer
buf.WriteString("// Code generated by Wire. DO NOT EDIT.\n\n")
buf.WriteString("//go:generate go run gortc.io/wire/cmd/wire\n")
buf.WriteString("//+build !wireinject\n\n")
buf.WriteString("package ")
buf.WriteString(g.pkg.Name)
buf.WriteString("\n\n")
if len(g.imports) > 0 {
buf.WriteString("import (\n")
imps := make([]string, 0, len(g.imports))
for path := range g.imports {
imps = append(imps, path)
}
sort.Strings(imps)
for _, path := range imps {
// Omit the local package identifier if it matches the package name.
info := g.imports[path]
if info.differs {
fmt.Fprintf(&buf, "\t%s %q\n", info.name, path)
} else {
fmt.Fprintf(&buf, "\t%q\n", path)
}
}
buf.WriteString(")\n\n")
}
if len(g.anonImports) > 0 {
buf.WriteString("import (\n")
anonImps := make([]string, 0, len(g.anonImports))
for path := range g.anonImports {
anonImps = append(anonImps, path)
}
sort.Strings(anonImps)
for _, path := range anonImps {
fmt.Fprintf(&buf, "\t_ %s\n", path)
}
buf.WriteString(")\n\n")
}
buf.Write(g.buf.Bytes())
return buf.Bytes()
}
// inject emits the code for an injector.
func (g *gen) inject(pos token.Pos, name string, sig *types.Signature, set *ProviderSet) []error {
injectSig, err := funcOutput(sig)
if err != nil {
return []error{notePosition(g.pkg.Fset.Position(pos),
fmt.Errorf("inject %s: %v", name, err))}
}
params := sig.Params()
calls, errs := solve(g.pkg.Fset, injectSig.out, params, set)
if len(errs) > 0 {
return mapErrors(errs, func(e error) error {
if w, ok := e.(*wireErr); ok {
return notePosition(w.position, fmt.Errorf("inject %s: %v", name, w.error))
}
return notePosition(g.pkg.Fset.Position(pos), fmt.Errorf("inject %s: %v", name, e))
})
}
type pendingVar struct {
name string
expr ast.Expr
typeInfo *types.Info
}
var pendingVars []pendingVar
ec := new(errorCollector)
for i := range calls {
c := &calls[i]
if c.hasCleanup && !injectSig.cleanup {
ts := types.TypeString(c.out, nil)
ec.add(notePosition(
g.pkg.Fset.Position(pos),
fmt.Errorf("inject %s: provider for %s returns cleanup but injection does not return cleanup function", name, ts)))
}
if c.hasErr && !injectSig.err {
ts := types.TypeString(c.out, nil)
ec.add(notePosition(
g.pkg.Fset.Position(pos),
fmt.Errorf("inject %s: provider for %s returns error but injection not allowed to fail", name, ts)))
}
if c.kind == valueExpr {
if err := accessibleFrom(c.valueTypeInfo, c.valueExpr, g.pkg.PkgPath); err != nil {
// TODO(light): Display line number of value expression.
ts := types.TypeString(c.out, nil)
ec.add(notePosition(
g.pkg.Fset.Position(pos),
fmt.Errorf("inject %s: value %s can't be used: %v", name, ts, err)))
}
if g.values[c.valueExpr] == "" {
t := c.valueTypeInfo.TypeOf(c.valueExpr)
name := typeVariableName(t, "", func(name string) string { return "_wire" + export(name) + "Value" }, g.nameInFileScope)
g.values[c.valueExpr] = name
pendingVars = append(pendingVars, pendingVar{
name: name,
expr: c.valueExpr,
typeInfo: c.valueTypeInfo,
})
}
}
}
if len(ec.errors) > 0 {
return ec.errors
}
// Perform one pass to collect all imports, followed by the real pass.
injectPass(name, sig, calls, set, &injectorGen{
g: g,
errVar: disambiguate("err", g.nameInFileScope),
discard: true,
})
injectPass(name, sig, calls, set, &injectorGen{
g: g,
errVar: disambiguate("err", g.nameInFileScope),
discard: false,
})
if len(pendingVars) > 0 {
g.p("var (\n")
for _, pv := range pendingVars {
g.p("\t%s = ", pv.name)
g.writeAST(pv.typeInfo, pv.expr)
g.p("\n")
}
g.p(")\n\n")
}
return nil
}
// rewritePkgRefs rewrites any package references in an AST into references for the
// generated package.
func (g *gen) rewritePkgRefs(info *types.Info, node ast.Node) ast.Node {
start, end := node.Pos(), node.End()
node = copyAST(node)
// First, rewrite all package names. This lets us know all the
// potentially colliding identifiers.
node = astutil.Apply(node, func(c *astutil.Cursor) bool {
switch node := c.Node().(type) {
case *ast.Ident:
// This is an unqualified identifier (qualified identifiers are peeled off below).
obj := info.ObjectOf(node)
if obj == nil {
return false
}
if pkg := obj.Pkg(); pkg != nil && obj.Parent() == pkg.Scope() && pkg.Path() != g.pkg.PkgPath {
// An identifier from either a dot import or read from a different package.
newPkgID := g.qualifyImport(pkg.Name(), pkg.Path())
c.Replace(&ast.SelectorExpr{
X: ast.NewIdent(newPkgID),
Sel: ast.NewIdent(node.Name),
})
return false
}
return true
case *ast.SelectorExpr:
pkgIdent, ok := node.X.(*ast.Ident)
if !ok {
return true
}
pkgName, ok := info.ObjectOf(pkgIdent).(*types.PkgName)
if !ok {
return true
}
// This is a qualified identifier. Rewrite and avoid visiting subexpressions.
imported := pkgName.Imported()
newPkgID := g.qualifyImport(imported.Name(), imported.Path())
c.Replace(&ast.SelectorExpr{
X: ast.NewIdent(newPkgID),
Sel: ast.NewIdent(node.Sel.Name),
})
return false
default:
return true
}
}, nil)
// Now that we have all the identifiers, rename any variables declared
// in this scope to not collide.
newNames := make(map[types.Object]string)
inNewNames := func(n string) bool {
for _, other := range newNames {
if other == n {
return true
}
}
return false
}
var scopeStack []*types.Scope
pkgScope := g.pkg.Types.Scope()
node = astutil.Apply(node, func(c *astutil.Cursor) bool {
if scope := info.Scopes[c.Node()]; scope != nil {
scopeStack = append(scopeStack, scope)
}
id, ok := c.Node().(*ast.Ident)
if !ok {
return true
}
obj := info.ObjectOf(id)
if obj == nil {
// We rewrote this identifier earlier, so it does not need
// further rewriting.
return true
}
if n, ok := newNames[obj]; ok {
// We picked a new name for this symbol. Rewrite it.
c.Replace(ast.NewIdent(n))
return false
}
if par := obj.Parent(); par == nil || par == pkgScope {
// Don't rename methods, field names, or top-level identifiers.
return true
}
// Rename any symbols defined within rewritePkgRefs's node that conflict
// with any symbols in the generated file.
objName := obj.Name()
if pos := obj.Pos(); pos < start || end <= pos || !(g.nameInFileScope(objName) || inNewNames(objName)) {
return true
}
newName := disambiguate(objName, func(n string) bool {
if g.nameInFileScope(n) || inNewNames(n) {
return true
}
if len(scopeStack) > 0 {
// Avoid picking a name that conflicts with other names in the
// current scope.
_, obj := scopeStack[len(scopeStack)-1].LookupParent(n, token.NoPos)
if obj != nil {
return true
}
}
return false
})
newNames[obj] = newName
c.Replace(ast.NewIdent(newName))
return false
}, func(c *astutil.Cursor) bool {
if info.Scopes[c.Node()] != nil {
// Should be top of stack; pop it.
scopeStack = scopeStack[:len(scopeStack)-1]
}
return true
})
return node
}
// writeAST prints an AST node into the generated output, rewriting any
// package references it encounters.
func (g *gen) writeAST(info *types.Info, node ast.Node) {
node = g.rewritePkgRefs(info, node)
if err := printer.Fprint(&g.buf, g.pkg.Fset, node); err != nil {
panic(err)
}
}
func (g *gen) qualifiedID(pkgName, pkgPath, sym string) string {
name := g.qualifyImport(pkgName, pkgPath)
if name == "" {
return sym
}
return name + "." + sym
}
func (g *gen) qualifyImport(name, path string) string {
if path == g.pkg.PkgPath {
return ""
}
// TODO(light): This is depending on details of the current loader.
const vendorPart = "vendor/"
unvendored := path
if i := strings.LastIndex(path, vendorPart); i != -1 && (i == 0 || path[i-1] == '/') {
unvendored = path[i+len(vendorPart):]
}
if info, ok := g.imports[unvendored]; ok {
return info.name
}
// TODO(light): Use parts of import path to disambiguate.
newName := disambiguate(name, func(n string) bool {
// Don't let an import take the "err" name. That's annoying.
return n == "err" || g.nameInFileScope(n)
})
g.imports[unvendored] = importInfo{
name: newName,
differs: newName != name,
}
return newName
}
func (g *gen) nameInFileScope(name string) bool {
for _, other := range g.imports {
if other.name == name {
return true
}
}
for _, other := range g.values {
if other == name {
return true
}
}
_, obj := g.pkg.Types.Scope().LookupParent(name, token.NoPos)
return obj != nil
}
func (g *gen) qualifyPkg(pkg *types.Package) string {
return g.qualifyImport(pkg.Name(), pkg.Path())
}
func (g *gen) p(format string, args ...interface{}) {
fmt.Fprintf(&g.buf, format, args...)
}
// injectorGen is the per-injector pass generator state.
type injectorGen struct {
g *gen
paramNames []string
localNames []string
cleanupNames []string
errVar string
// discard causes ig.p and ig.writeAST to no-op. Useful to run
// generation for side-effects like filling in g.imports.
discard bool
}
// injectPass generates an injector given the output from analysis.
// The sig passed in should be verified.
func injectPass(name string, sig *types.Signature, calls []call, set *ProviderSet, ig *injectorGen) {
params := sig.Params()
injectSig, err := funcOutput(sig)
if err != nil {
// This should be checked by the caller already.
panic(err)
}
ig.p("func %s(", name)
for i := 0; i < params.Len(); i++ {
if i > 0 {
ig.p(", ")
}
pi := params.At(i)
a := pi.Name()
if a == "" || a == "_" {
a = typeVariableName(pi.Type(), "arg", unexport, ig.nameInInjector)
} else {
a = disambiguate(a, ig.nameInInjector)
}
ig.paramNames = append(ig.paramNames, a)
if sig.Variadic() && i == params.Len()-1 {
// Keep the varargs signature instead of a slice for the last argument if the
// injector is variadic.
ig.p("%s ...%s", ig.paramNames[i], types.TypeString(pi.Type().(*types.Slice).Elem(), ig.g.qualifyPkg))
} else {
ig.p("%s %s", ig.paramNames[i], types.TypeString(pi.Type(), ig.g.qualifyPkg))
}
}
outTypeString := types.TypeString(injectSig.out, ig.g.qualifyPkg)
switch {
case injectSig.cleanup && injectSig.err:
ig.p(") (%s, func(), error) {\n", outTypeString)
case injectSig.cleanup:
ig.p(") (%s, func()) {\n", outTypeString)
case injectSig.err:
ig.p(") (%s, error) {\n", outTypeString)
default:
ig.p(") %s {\n", outTypeString)
}
for i := range calls {
c := &calls[i]
lname := typeVariableName(c.out, "v", unexport, ig.nameInInjector)
ig.localNames = append(ig.localNames, lname)
switch c.kind {
case structProvider:
ig.structProviderCall(lname, c)
case funcProviderCall:
ig.funcProviderCall(lname, c, injectSig)
case valueExpr:
ig.valueExpr(lname, c)
case selectorExpr:
ig.fieldExpr(lname, c)
default:
panic("unknown kind")
}
}
if len(calls) == 0 {
ig.p("\treturn %s", ig.paramNames[set.For(injectSig.out).Arg().Index])
} else {
ig.p("\treturn %s", ig.localNames[len(calls)-1])
}
if injectSig.cleanup {
ig.p(", func() {\n")
for i := len(ig.cleanupNames) - 1; i >= 0; i-- {
ig.p("\t\t%s()\n", ig.cleanupNames[i])
}
ig.p("\t}")
}
if injectSig.err {
ig.p(", nil")
}
ig.p("\n}\n\n")
}
func (ig *injectorGen) funcProviderCall(lname string, c *call, injectSig outputSignature) {
ig.p("\t%s", lname)
prevCleanup := len(ig.cleanupNames)
if c.hasCleanup {
cname := disambiguate("cleanup", ig.nameInInjector)
ig.cleanupNames = append(ig.cleanupNames, cname)
ig.p(", %s", cname)
}
if c.hasErr {
ig.p(", %s", ig.errVar)
}
ig.p(" := ")
ig.p("%s(", ig.g.qualifiedID(c.pkg.Name(), c.pkg.Path(), c.name))
for i, a := range c.args {
if i > 0 {
ig.p(", ")
}
if a < len(ig.paramNames) {
ig.p("%s", ig.paramNames[a])
} else {
ig.p("%s", ig.localNames[a-len(ig.paramNames)])
}
}
if c.varargs {
ig.p("...")
}
ig.p(")\n")
if c.hasErr {
ig.p("\tif %s != nil {\n", ig.errVar)
for i := prevCleanup - 1; i >= 0; i-- {
ig.p("\t\t%s()\n", ig.cleanupNames[i])
}
ig.p("\t\treturn %s", zeroValue(injectSig.out, ig.g.qualifyPkg))
if injectSig.cleanup {
ig.p(", nil")
}
// TODO(light): Give information about failing provider.
ig.p(", err\n")
ig.p("\t}\n")
}
}
func (ig *injectorGen) structProviderCall(lname string, c *call) {
ig.p("\t%s", lname)
ig.p(" := ")
if _, ok := c.out.(*types.Pointer); ok {
ig.p("&")
}
ig.p("%s{\n", ig.g.qualifiedID(c.pkg.Name(), c.pkg.Path(), c.name))
for i, a := range c.args {
ig.p("\t\t%s: ", c.fieldNames[i])
if a < len(ig.paramNames) {
ig.p("%s", ig.paramNames[a])
} else {
ig.p("%s", ig.localNames[a-len(ig.paramNames)])
}
ig.p(",\n")
}
ig.p("\t}\n")
}
func (ig *injectorGen) valueExpr(lname string, c *call) {
ig.p("\t%s := %s\n", lname, ig.g.values[c.valueExpr])
}
func (ig *injectorGen) fieldExpr(lname string, c *call) {
a := c.args[0]
ig.p("\t%s := ", lname)
if c.ptrToField {
ig.p("&")
}
if a < len(ig.paramNames) {
ig.p("%s.%s\n", ig.paramNames[a], c.name)
} else {
ig.p("%s.%s\n", ig.localNames[a-len(ig.paramNames)], c.name)
}
}
// nameInInjector reports whether name collides with any other identifier
// in the current injector.
func (ig *injectorGen) nameInInjector(name string) bool {
if name == ig.errVar {
return true
}
for _, a := range ig.paramNames {
if a == name {
return true
}
}
for _, l := range ig.localNames {
if l == name {
return true
}
}
for _, l := range ig.cleanupNames {
if l == name {
return true
}
}
return ig.g.nameInFileScope(name)
}
func (ig *injectorGen) p(format string, args ...interface{}) {
if ig.discard {
return
}
ig.g.p(format, args...)
}
func (ig *injectorGen) writeAST(info *types.Info, node ast.Node) {
node = ig.g.rewritePkgRefs(info, node)
if ig.discard {
return
}
if err := printer.Fprint(&ig.g.buf, ig.g.pkg.Fset, node); err != nil {
panic(err)
}
}
// zeroValue returns the shortest expression that evaluates to the zero
// value for the given type.
func zeroValue(t types.Type, qf types.Qualifier) string {
switch u := t.Underlying().(type) {
case *types.Array, *types.Struct:
return types.TypeString(t, qf) + "{}"
case *types.Basic:
info := u.Info()
switch {
case info&types.IsBoolean != 0:
return "false"
case info&(types.IsInteger|types.IsFloat|types.IsComplex) != 0:
return "0"
case info&types.IsString != 0:
return `""`
default:
panic("unreachable")
}
case *types.Chan, *types.Interface, *types.Map, *types.Pointer, *types.Signature, *types.Slice:
return "nil"
default:
panic("unreachable")
}
}
// typeVariableName invents a disambiguated variable name derived from the type name.
// If no name can be derived from the type, defaultName is used.
// transform is used to transform the derived name(s) (including defaultName);
// commonly used functions include export and unexport.
// collides is used to see if a name is ambiguous. If any one of the derived
// names is unambiguous, it used; otherwise, the first derived name is
// disambiguated using disambiguate().
func typeVariableName(t types.Type, defaultName string, transform func(string) string, collides func(string) bool) string {
if p, ok := t.(*types.Pointer); ok {
t = p.Elem()
}
var names []string
switch t := t.(type) {
case *types.Basic:
if t.Name() != "" {
names = append(names, t.Name())
}
case *types.Named:
obj := t.Obj()
if name := obj.Name(); name != "" {
names = append(names, name)
}
// Provide an alternate name prefixed with the package name if possible.
// E.g., in case of collisions, we'll use "fooCfg" instead of "cfg2".
if pkg := obj.Pkg(); pkg != nil && pkg.Name() != "" {
names = append(names, fmt.Sprintf("%s%s", pkg.Name(), strings.Title(obj.Name())))
}
}
// If we were unable to derive a name, use defaultName.
if len(names) == 0 {
names = append(names, defaultName)
}
// Transform the name(s).
for i, name := range names {
names[i] = transform(name)
}
// See if there's an unambiguous name; if so, use it.
for _, name := range names {
if !token.Lookup(name).IsKeyword() && !collides(name) {
return name
}
}
// Otherwise, disambiguate the first name.
return disambiguate(names[0], collides)
}
// unexport converts a name that is potentially exported to an unexported name.
func unexport(name string) string {
if name == "" {
return ""
}
r, sz := utf8.DecodeRuneInString(name)
if !unicode.IsUpper(r) {
// foo -> foo
return name
}
r2, sz2 := utf8.DecodeRuneInString(name[sz:])
if !unicode.IsUpper(r2) {
// Foo -> foo
return string(unicode.ToLower(r)) + name[sz:]
}
// UPPERWord -> upperWord
sbuf := new(strings.Builder)
sbuf.WriteRune(unicode.ToLower(r))
i := sz
r, sz = r2, sz2
for unicode.IsUpper(r) && sz > 0 {
r2, sz2 := utf8.DecodeRuneInString(name[i+sz:])
if sz2 > 0 && unicode.IsLower(r2) {
break
}
i += sz
sbuf.WriteRune(unicode.ToLower(r))
r, sz = r2, sz2
}
sbuf.WriteString(name[i:])
return sbuf.String()
}
// export converts a name that is potentially unexported to an exported name.
func export(name string) string {
if name == "" {
return ""
}
r, sz := utf8.DecodeRuneInString(name)
if unicode.IsUpper(r) {
// Foo -> Foo
return name
}
// fooBar -> FooBar
sbuf := new(strings.Builder)
sbuf.WriteRune(unicode.ToUpper(r))
sbuf.WriteString(name[sz:])
return sbuf.String()
}
// disambiguate picks a unique name, preferring name if it is already unique.
// It also disambiguates against Go's reserved keywords.
func disambiguate(name string, collides func(string) bool) string {
if !token.Lookup(name).IsKeyword() && !collides(name) {
return name
}
buf := []byte(name)
if len(buf) > 0 && buf[len(buf)-1] >= '0' && buf[len(buf)-1] <= '9' {
buf = append(buf, '_')
}
base := len(buf)
for n := 2; ; n++ {
buf = strconv.AppendInt(buf[:base], int64(n), 10)
sbuf := string(buf)
if !token.Lookup(sbuf).IsKeyword() && !collides(sbuf) {
return sbuf
}
}
}
// accessibleFrom reports whether node can be copied to wantPkg without
// violating Go visibility rules.
func accessibleFrom(info *types.Info, node ast.Node, wantPkg string) error {
var unexportError error
ast.Inspect(node, func(node ast.Node) bool {
if unexportError != nil {
return false
}
ident, ok := node.(*ast.Ident)
if !ok {
return true
}
obj := info.ObjectOf(ident)
if _, ok := obj.(*types.PkgName); ok {
// Local package names are fine, since we can just reimport them.
return true
}
if pkg := obj.Pkg(); pkg != nil {
if !ast.IsExported(ident.Name) && pkg.Path() != wantPkg {
unexportError = fmt.Errorf("uses unexported identifier %s", obj.Name())
return false
}
if obj.Parent() != nil && obj.Parent() != pkg.Scope() {
unexportError = fmt.Errorf("%s is not declared in package scope", obj.Name())
return false
}
}
return true
})
return unexportError
}
var (
errorType = types.Universe.Lookup("error").Type()
cleanupType = types.NewSignature(nil, nil, nil, false)
)