Golang File.Imports方法代码示例

// addImport adds the import path to the file f, if absent.
func addImport(f *ast.File, path string) {
	if imports(f, path) {
		return
	}

	newImport := &ast.ImportSpec{
		Path: &ast.BasicLit{
			Kind:  token.STRING,
			Value: strconv.Quote(path),
		},
	}

	var impdecl *ast.GenDecl

	// Find an import decl to add to.
	for _, decl := range f.Decls {
		gen, ok := decl.(*ast.GenDecl)

		if ok && gen.Tok == token.IMPORT {
			impdecl = gen
			break
		}
	}

	// No import decl found.  Add one.
	if impdecl == nil {
		impdecl = &ast.GenDecl{
			Tok: token.IMPORT,
		}
		f.Decls = append(f.Decls, nil)
		copy(f.Decls[1:], f.Decls)
		f.Decls[0] = impdecl
	}

	// Ensure the import decl has parentheses, if needed.
	if len(impdecl.Specs) > 0 && !impdecl.Lparen.IsValid() {
		impdecl.Lparen = impdecl.Pos()
	}

	// Assume the import paths are alphabetically ordered.
	// If they are not, the result is ugly, but legal.
	insertAt := len(impdecl.Specs) // default to end of specs
	for i, spec := range impdecl.Specs {
		impspec := spec.(*ast.ImportSpec)
		if importPath(impspec) > path {
			insertAt = i
			break
		}
	}

	impdecl.Specs = append(impdecl.Specs, nil)
	copy(impdecl.Specs[insertAt+1:], impdecl.Specs[insertAt:])
	impdecl.Specs[insertAt] = newImport

	f.Imports = append(f.Imports, newImport)
}

// deleteImport deletes the import path from the file f, if present.
func deleteImport(f *ast.File, path string) (deleted bool) {
	oldImport := importSpec(f, path)

	// Find the import node that imports path, if any.
	for i, decl := range f.Decls {
		gen, ok := decl.(*ast.GenDecl)
		if !ok || gen.Tok != token.IMPORT {
			continue
		}
		for j, spec := range gen.Specs {
			impspec := spec.(*ast.ImportSpec)
			if oldImport != impspec {
				continue
			}

			// We found an import spec that imports path.
			// Delete it.
			deleted = true
			copy(gen.Specs[j:], gen.Specs[j+1:])
			gen.Specs = gen.Specs[:len(gen.Specs)-1]

			// If this was the last import spec in this decl,
			// delete the decl, too.
			if len(gen.Specs) == 0 {
				copy(f.Decls[i:], f.Decls[i+1:])
				f.Decls = f.Decls[:len(f.Decls)-1]
			} else if len(gen.Specs) == 1 {
				gen.Lparen = token.NoPos // drop parens
			}
			if j > 0 {
				// We deleted an entry but now there will be
				// a blank line-sized hole where the import was.
				// Close the hole by making the previous
				// import appear to "end" where this one did.
				gen.Specs[j-1].(*ast.ImportSpec).EndPos = impspec.End()
			}
			break
		}
	}

	// Delete it from f.Imports.
	for i, imp := range f.Imports {
		if imp == oldImport {
			copy(f.Imports[i:], f.Imports[i+1:])
			f.Imports = f.Imports[:len(f.Imports)-1]
			break
		}
	}

	return
}

func addImport(file *ast.File, pkg string) {
	decl := &ast.GenDecl{
		Tok: token.IMPORT,
	}
	file.Decls = append(file.Decls, nil)
	copy(file.Decls[1:], file.Decls[:])
	file.Decls[0] = decl
	spec := &ast.ImportSpec{
		Path: &ast.BasicLit{
			Kind:  token.STRING,
			Value: pkg,
		},
	}
	decl.Specs = append(decl.Specs, spec)
	file.Imports = append(file.Imports, spec)
}

// deleteImport deletes the import path from the file f, if present.
func deleteImport(f *ast.File, path string) {
	oldImport := importSpec(f, path)

	// Find the import node that imports path, if any.
	for i, decl := range f.Decls {
		gen, ok := decl.(*ast.GenDecl)
		if !ok || gen.Tok != token.IMPORT {
			continue
		}
		for j, spec := range gen.Specs {
			impspec := spec.(*ast.ImportSpec)

			if oldImport != impspec {
				continue
			}

			// We found an import spec that imports path.
			// Delete it.
			copy(gen.Specs[j:], gen.Specs[j+1:])
			gen.Specs = gen.Specs[:len(gen.Specs)-1]

			// If this was the last import spec in this decl,
			// delete the decl, too.
			if len(gen.Specs) == 0 {
				copy(f.Decls[i:], f.Decls[i+1:])
				f.Decls = f.Decls[:len(f.Decls)-1]
			} else if len(gen.Specs) == 1 {
				gen.Lparen = token.NoPos // drop parens
			}

			break
		}
	}

	// Delete it from f.Imports.
	for i, imp := range f.Imports {
		if imp == oldImport {
			copy(f.Imports[i:], f.Imports[i+1:])
			f.Imports = f.Imports[:len(f.Imports)-1]
			break
		}
	}
}

// AddNamedImport adds the import path to the file f, if absent.
// If name is not empty, it is used to rename the import.
//
// For example, calling
//	AddNamedImport(fset, f, "pathpkg", "path")
// adds
//	import pathpkg "path"
func AddNamedImport(fset *token.FileSet, f *ast.File, name, ipath string) (added bool) {
	if imports(f, ipath) {
		return false
	}

	newImport := &ast.ImportSpec{
		Path: &ast.BasicLit{
			Kind:  token.STRING,
			Value: strconv.Quote(ipath),
		},
	}
	if name != "" {
		newImport.Name = &ast.Ident{Name: name}
	}

	// Find an import decl to add to.
	// The goal is to find an existing import
	// whose import path has the longest shared
	// prefix with ipath.
	var (
		bestMatch  = -1         // length of longest shared prefix
		lastImport = -1         // index in f.Decls of the file's final import decl
		impDecl    *ast.GenDecl // import decl containing the best match
		impIndex   = -1         // spec index in impDecl containing the best match
	)
	for i, decl := range f.Decls {
		gen, ok := decl.(*ast.GenDecl)
		if ok && gen.Tok == token.IMPORT {
			lastImport = i
			// Do not add to import "C", to avoid disrupting the
			// association with its doc comment, breaking cgo.
			if declImports(gen, "C") {
				continue
			}

			// Match an empty import decl if that's all that is available.
			if len(gen.Specs) == 0 && bestMatch == -1 {
				impDecl = gen
			}

			// Compute longest shared prefix with imports in this group.
			for j, spec := range gen.Specs {
				impspec := spec.(*ast.ImportSpec)
				n := matchLen(importPath(impspec), ipath)
				if n > bestMatch {
					bestMatch = n
					impDecl = gen
					impIndex = j
				}
			}
		}
	}

	// If no import decl found, add one after the last import.
	if impDecl == nil {
		impDecl = &ast.GenDecl{
			Tok: token.IMPORT,
		}
		if lastImport >= 0 {
			impDecl.TokPos = f.Decls[lastImport].End()
		} else {
			// There are no existing imports.
			// Our new import goes after the package declaration and after
			// the comment, if any, that starts on the same line as the
			// package declaration.
			impDecl.TokPos = f.Package

			file := fset.File(f.Package)
			pkgLine := file.Line(f.Package)
			for _, c := range f.Comments {
				if file.Line(c.Pos()) > pkgLine {
					break
				}
				impDecl.TokPos = c.End()
			}
		}
		f.Decls = append(f.Decls, nil)
		copy(f.Decls[lastImport+2:], f.Decls[lastImport+1:])
		f.Decls[lastImport+1] = impDecl
	}

	// Insert new import at insertAt.
	insertAt := 0
	if impIndex >= 0 {
		// insert after the found import
		insertAt = impIndex + 1
	}
	impDecl.Specs = append(impDecl.Specs, nil)
	copy(impDecl.Specs[insertAt+1:], impDecl.Specs[insertAt:])
	impDecl.Specs[insertAt] = newImport
	pos := impDecl.Pos()
	if insertAt > 0 {
		// If there is a comment after an existing import, preserve the comment
//.........这里部分代码省略.........

// DeleteNamedImport deletes the import with the given name and path from the file f, if present.
func DeleteNamedImport(fset *token.FileSet, f *ast.File, name, path string) (deleted bool) {
	var delspecs []*ast.ImportSpec
	var delcomments []*ast.CommentGroup

	// Find the import nodes that import path, if any.
	for i := 0; i < len(f.Decls); i++ {
		decl := f.Decls[i]
		gen, ok := decl.(*ast.GenDecl)
		if !ok || gen.Tok != token.IMPORT {
			continue
		}
		for j := 0; j < len(gen.Specs); j++ {
			spec := gen.Specs[j]
			impspec := spec.(*ast.ImportSpec)
			if impspec.Name == nil && name != "" {
				continue
			}
			if impspec.Name != nil && impspec.Name.Name != name {
				continue
			}
			if importPath(impspec) != path {
				continue
			}

			// We found an import spec that imports path.
			// Delete it.
			delspecs = append(delspecs, impspec)
			deleted = true
			copy(gen.Specs[j:], gen.Specs[j+1:])
			gen.Specs = gen.Specs[:len(gen.Specs)-1]

			// If this was the last import spec in this decl,
			// delete the decl, too.
			if len(gen.Specs) == 0 {
				copy(f.Decls[i:], f.Decls[i+1:])
				f.Decls = f.Decls[:len(f.Decls)-1]
				i--
				break
			} else if len(gen.Specs) == 1 {
				if impspec.Doc != nil {
					delcomments = append(delcomments, impspec.Doc)
				}
				if impspec.Comment != nil {
					delcomments = append(delcomments, impspec.Comment)
				}
				for _, cg := range f.Comments {
					// Found comment on the same line as the import spec.
					if cg.End() < impspec.Pos() && fset.Position(cg.End()).Line == fset.Position(impspec.Pos()).Line {
						delcomments = append(delcomments, cg)
						break
					}
				}

				gen.Lparen = token.NoPos // drop parens
				spec := gen.Specs[0].(*ast.ImportSpec)
				if spec.Doc != nil {
					// Move the documentation above the import statement.
					gen.TokPos = spec.Doc.End() + 1
				}

				for _, cg := range f.Comments {
					if cg.End() < spec.Pos() && fset.Position(cg.End()).Line == fset.Position(spec.Pos()).Line {
						for fset.Position(gen.TokPos).Line != fset.Position(spec.Pos()).Line {
							fset.File(gen.TokPos).MergeLine(fset.Position(gen.TokPos).Line)
						}
						break
					}
				}
			}
			if j > 0 {
				lastImpspec := gen.Specs[j-1].(*ast.ImportSpec)
				lastLine := fset.Position(lastImpspec.Path.ValuePos).Line
				line := fset.Position(impspec.Path.ValuePos).Line

				// We deleted an entry but now there may be
				// a blank line-sized hole where the import was.
				if line-lastLine > 1 {
					// There was a blank line immediately preceding the deleted import,
					// so there's no need to close the hole.
					// Do nothing.
				} else {
					// There was no blank line. Close the hole.
					fset.File(gen.Rparen).MergeLine(line)
				}
			}
			j--
		}
	}

	// Delete imports from f.Imports.
	for i := 0; i < len(f.Imports); i++ {
		imp := f.Imports[i]
		for j, del := range delspecs {
			if imp == del {
				copy(f.Imports[i:], f.Imports[i+1:])
				f.Imports = f.Imports[:len(f.Imports)-1]
				copy(delspecs[j:], delspecs[j+1:])
				delspecs = delspecs[:len(delspecs)-1]
				i--
//.........这里部分代码省略.........

// AddNamedImport adds the import path to the file f, if absent.
// If name is not empty, it is used to rename the import.
//
// For example, calling
//	AddNamedImport(fset, f, "pathpkg", "path")
// adds
//	import pathpkg "path"
func AddNamedImport(fset *token.FileSet, f *ast.File, name, ipath string) (added bool) {
	if imports(f, ipath) {
		return false
	}

	newImport := &ast.ImportSpec{
		Path: &ast.BasicLit{
			Kind:  token.STRING,
			Value: strconv.Quote(ipath),
		},
	}
	if name != "" {
		newImport.Name = &ast.Ident{Name: name}
	}

	// Find an import decl to add to.
	var (
		bestMatch  = -1
		lastImport = -1
		impDecl    *ast.GenDecl
		impIndex   = -1
		hasImports = false
	)
	for i, decl := range f.Decls {
		gen, ok := decl.(*ast.GenDecl)
		if ok && gen.Tok == token.IMPORT {
			hasImports = true
			lastImport = i
			// Do not add to import "C", to avoid disrupting the
			// association with its doc comment, breaking cgo.
			if declImports(gen, "C") {
				continue
			}

			// Compute longest shared prefix with imports in this block.
			for j, spec := range gen.Specs {
				impspec := spec.(*ast.ImportSpec)
				n := matchLen(importPath(impspec), ipath)
				if n > bestMatch {
					bestMatch = n
					impDecl = gen
					impIndex = j
				}
			}
		}
	}

	// If no import decl found, add one after the last import.
	if impDecl == nil {
		// TODO(bradfitz): remove this hack. See comment below on
		// addImportViaSourceModification.
		if !hasImports {
			f2, err := addImportViaSourceModification(fset, f, name, ipath)
			if err == nil {
				*f = *f2
				return true
			}
			log.Printf("addImportViaSourceModification error: %v", err)
		}

		// TODO(bradfitz): fix above and resume using this old code:
		impDecl = &ast.GenDecl{
			Tok: token.IMPORT,
		}
		f.Decls = append(f.Decls, nil)
		copy(f.Decls[lastImport+2:], f.Decls[lastImport+1:])
		f.Decls[lastImport+1] = impDecl
	}

	// Ensure the import decl has parentheses, if needed.
	if len(impDecl.Specs) > 0 && !impDecl.Lparen.IsValid() {
		impDecl.Lparen = impDecl.Pos()
	}

	insertAt := impIndex + 1
	if insertAt == 0 {
		insertAt = len(impDecl.Specs)
	}
	impDecl.Specs = append(impDecl.Specs, nil)
	copy(impDecl.Specs[insertAt+1:], impDecl.Specs[insertAt:])
	impDecl.Specs[insertAt] = newImport
	if insertAt > 0 {
		// Assign same position as the previous import,
		// so that the sorter sees it as being in the same block.
		prev := impDecl.Specs[insertAt-1]
		newImport.Path.ValuePos = prev.Pos()
		newImport.EndPos = prev.Pos()
	}
	if len(impDecl.Specs) > 1 && impDecl.Lparen == 0 {
		// set Lparen to something not zero, so the printer prints
		// the full block rather just the first ImportSpec.
		impDecl.Lparen = 1
	}
//.........这里部分代码省略.........

// DeleteImport deletes the import path from the file f, if present.
func DeleteImport(fset *token.FileSet, f *ast.File, path string) (deleted bool) {
	var delspecs []*ast.ImportSpec

	// Find the import nodes that import path, if any.
	for i := 0; i < len(f.Decls); i++ {
		decl := f.Decls[i]
		gen, ok := decl.(*ast.GenDecl)
		if !ok || gen.Tok != token.IMPORT {
			continue
		}
		for j := 0; j < len(gen.Specs); j++ {
			spec := gen.Specs[j]
			impspec := spec.(*ast.ImportSpec)
			if importPath(impspec) != path {
				continue
			}

			// We found an import spec that imports path.
			// Delete it.
			delspecs = append(delspecs, impspec)
			deleted = true
			copy(gen.Specs[j:], gen.Specs[j+1:])
			gen.Specs = gen.Specs[:len(gen.Specs)-1]

			// If this was the last import spec in this decl,
			// delete the decl, too.
			if len(gen.Specs) == 0 {
				copy(f.Decls[i:], f.Decls[i+1:])
				f.Decls = f.Decls[:len(f.Decls)-1]
				i--
				break
			} else if len(gen.Specs) == 1 {
				gen.Lparen = token.NoPos // drop parens
			}
			if j > 0 {
				lastImpspec := gen.Specs[j-1].(*ast.ImportSpec)
				lastLine := fset.Position(lastImpspec.Path.ValuePos).Line
				line := fset.Position(impspec.Path.ValuePos).Line

				// We deleted an entry but now there may be
				// a blank line-sized hole where the import was.
				if line-lastLine > 1 {
					// There was a blank line immediately preceding the deleted import,
					// so there's no need to close the hole.
					// Do nothing.
				} else {
					// There was no blank line. Close the hole.
					fset.File(gen.Rparen).MergeLine(line)
				}
			}
			j--
		}
	}

	// Delete them from f.Imports.
	for i := 0; i < len(f.Imports); i++ {
		imp := f.Imports[i]
		for j, del := range delspecs {
			if imp == del {
				copy(f.Imports[i:], f.Imports[i+1:])
				f.Imports = f.Imports[:len(f.Imports)-1]
				copy(delspecs[j:], delspecs[j+1:])
				delspecs = delspecs[:len(delspecs)-1]
				i--
				break
			}
		}
	}

	if len(delspecs) > 0 {
		panic(fmt.Sprintf("deleted specs from Decls but not Imports: %v", delspecs))
	}

	return
}

// addImport adds the import path to the file f, if absent.
func addImport(f *ast.File, ipath string) (added bool) {
	if imports(f, ipath) {
		return false
	}

	// Determine name of import.
	// Assume added imports follow convention of using last element.
	_, name := path.Split(ipath)

	// Rename any conflicting top-level references from name to name_.
	renameTop(f, name, name+"_")

	newImport := &ast.ImportSpec{
		Path: &ast.BasicLit{
			Kind:  token.STRING,
			Value: strconv.Quote(ipath),
		},
	}

	// Find an import decl to add to.
	var (
		bestMatch  = -1
		lastImport = -1
		impDecl    *ast.GenDecl
		impIndex   = -1
	)
	for i, decl := range f.Decls {
		gen, ok := decl.(*ast.GenDecl)
		if ok && gen.Tok == token.IMPORT {
			lastImport = i
			// Do not add to import "C", to avoid disrupting the
			// association with its doc comment, breaking cgo.
			if declImports(gen, "C") {
				continue
			}

			// Compute longest shared prefix with imports in this block.
			for j, spec := range gen.Specs {
				impspec := spec.(*ast.ImportSpec)
				n := matchLen(importPath(impspec), ipath)
				if n > bestMatch {
					bestMatch = n
					impDecl = gen
					impIndex = j
				}
			}
		}
	}

	// If no import decl found, add one after the last import.
	if impDecl == nil {
		impDecl = &ast.GenDecl{
			Tok: token.IMPORT,
		}
		f.Decls = append(f.Decls, nil)
		copy(f.Decls[lastImport+2:], f.Decls[lastImport+1:])
		f.Decls[lastImport+1] = impDecl
	}

	// Ensure the import decl has parentheses, if needed.
	if len(impDecl.Specs) > 0 && !impDecl.Lparen.IsValid() {
		impDecl.Lparen = impDecl.Pos()
	}

	insertAt := impIndex + 1
	if insertAt == 0 {
		insertAt = len(impDecl.Specs)
	}
	impDecl.Specs = append(impDecl.Specs, nil)
	copy(impDecl.Specs[insertAt+1:], impDecl.Specs[insertAt:])
	impDecl.Specs[insertAt] = newImport
	if insertAt > 0 {
		// Assign same position as the previous import,
		// so that the sorter sees it as being in the same block.
		prev := impDecl.Specs[insertAt-1]
		newImport.Path.ValuePos = prev.Pos()
		newImport.EndPos = prev.Pos()
	}

	f.Imports = append(f.Imports, newImport)
	return true
}

func fixImports(f *ast.File) {
	declShort := map[string]*ast.ImportSpec{} // key: either base package "fmt", "http" or renamed package
	usedShort := map[string]bool{}            // Same key
	var genDecls []*ast.GenDecl

	addImport := func(ipath string) {
		is := &ast.ImportSpec{
			Path: &ast.BasicLit{
				Kind:  token.STRING,
				Value: strconv.Quote(ipath),
			},
		}
		declShort[path.Base(ipath)] = is

		if len(genDecls) == 0 {
			genDecls = append(genDecls, &ast.GenDecl{
				Tok: token.IMPORT,
			})
			f.Decls = append([]ast.Decl{genDecls[0]}, f.Decls...)
			f.Imports = append(f.Imports, is)
		}
		gd0 := genDecls[0]
		// Prepend onto gd0.Specs:
		// Make room for it (nil), slide everything down, then set [0].
		gd0.Specs = append(gd0.Specs, nil)
		copy(gd0.Specs[1:], gd0.Specs[:])
		gd0.Specs[0] = is

		if len(gd0.Specs) > 1 && gd0.Lparen == 0 {
			gd0.Lparen = 1 // something not zero
		}
	}

	var visitor visitFn
	depth := 0
	visitor = visitFn(func(node ast.Node) ast.Visitor {
		if node == nil {
			depth--
			return visitor
		}
		depth++
		switch v := node.(type) {
		case *ast.GenDecl:
			if v.Tok == token.IMPORT {
				genDecls = append(genDecls, v)
			}
		case *ast.ImportSpec:
			if v.Name != nil {
				declShort[v.Name.Name] = v
			} else {
				local := path.Base(strings.Trim(v.Path.Value, `\"`))
				declShort[local] = v
			}
		case *ast.SelectorExpr:
			if xident, ok := v.X.(*ast.Ident); ok {
				pkgName := xident.Name
				usedShort[pkgName] = true
				if declShort[pkgName] == nil {
					key := pkgName + "." + v.Sel.Name
					if fullImport, ok := common[key]; ok {
						addImport(fullImport)
					}
				}
			}
		}
		// fmt.Printf("%ssaw a %T\n", indent, node)
		return visitor
	})
	ast.Walk(visitor, f)

	// Nil out any unused ImportSpecs, to be removed in following passes
	unusedImport := map[*ast.ImportSpec]bool{}
	for pkg, is := range declShort {
		if !usedShort[pkg] && pkg != "_" && pkg != "." {
			unusedImport[is] = true
		}
	}

	for _, gd := range genDecls {
		gd.Specs = filterUnusedSpecs(unusedImport, gd.Specs)
		if len(gd.Specs) == 1 {
			gd.Lparen = 0
		}
	}

	f.Decls = filterEmptyDecls(f.Decls)
	f.Imports = filterUnusedImports(unusedImport, f.Imports)
}

// DeleteImport deletes the import path from the file f, if present.
func DeleteImport(fset *token.FileSet, f *ast.File, path string) (deleted bool) {
	oldImport := importSpec(f, path)

	// Find the import node that imports path, if any.
	for i, decl := range f.Decls {
		gen, ok := decl.(*ast.GenDecl)
		if !ok || gen.Tok != token.IMPORT {
			continue
		}
		for j, spec := range gen.Specs {
			impspec := spec.(*ast.ImportSpec)
			if oldImport != impspec {
				continue
			}

			// We found an import spec that imports path.
			// Delete it.
			deleted = true
			copy(gen.Specs[j:], gen.Specs[j+1:])
			gen.Specs = gen.Specs[:len(gen.Specs)-1]

			// If this was the last import spec in this decl,
			// delete the decl, too.
			if len(gen.Specs) == 0 {
				copy(f.Decls[i:], f.Decls[i+1:])
				f.Decls = f.Decls[:len(f.Decls)-1]
			} else if len(gen.Specs) == 1 {
				gen.Lparen = token.NoPos // drop parens
			}
			if j > 0 {
				lastImpspec := gen.Specs[j-1].(*ast.ImportSpec)
				lastLine := fset.Position(lastImpspec.Path.ValuePos).Line
				line := fset.Position(impspec.Path.ValuePos).Line

				// We deleted an entry but now there may be
				// a blank line-sized hole where the import was.
				if line-lastLine > 1 {
					// There was a blank line immediately preceeing the deleted import,
					// so there's no need to close the hole.
					// Do nothing.
				} else {
					// There was no blank line.
					// Close the hole by making the previous
					// import appear to "end" where this one did.
					lastImpspec.EndPos = impspec.End()
				}
			}
			break
		}
	}

	// Delete it from f.Imports.
	for i, imp := range f.Imports {
		if imp == oldImport {
			copy(f.Imports[i:], f.Imports[i+1:])
			f.Imports = f.Imports[:len(f.Imports)-1]
			break
		}
	}

	return
}