Merge tag 'upstream/1.4' into debian-experimental

* tag 'upstream/1.4':
  Imported Upstream version 1.4

1 files changed, 198 insertions, 0 deletions

diff --git a/src/go/parser/interface.go b/src/go/parser/interface.go
new file mode 100644
index 000000000..49103058b
--- /dev/null
+++ b/src/go/parser/interface.go
@@ -0,0 +1,198 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file contains the exported entry points for invoking the parser.
+
+package parser
+
+import (
+	"bytes"
+	"errors"
+	"go/ast"
+	"go/token"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// If src != nil, readSource converts src to a []byte if possible;
+// otherwise it returns an error. If src == nil, readSource returns
+// the result of reading the file specified by filename.
+//
+func readSource(filename string, src interface{}) ([]byte, error) {
+	if src != nil {
+		switch s := src.(type) {
+		case string:
+			return []byte(s), nil
+		case []byte:
+			return s, nil
+		case *bytes.Buffer:
+			// is io.Reader, but src is already available in []byte form
+			if s != nil {
+				return s.Bytes(), nil
+			}
+		case io.Reader:
+			var buf bytes.Buffer
+			if _, err := io.Copy(&buf, s); err != nil {
+				return nil, err
+			}
+			return buf.Bytes(), nil
+		}
+		return nil, errors.New("invalid source")
+	}
+	return ioutil.ReadFile(filename)
+}
+
+// A Mode value is a set of flags (or 0).
+// They control the amount of source code parsed and other optional
+// parser functionality.
+//
+type Mode uint
+
+const (
+	PackageClauseOnly Mode             = 1 << iota // stop parsing after package clause
+	ImportsOnly                                    // stop parsing after import declarations
+	ParseComments                                  // parse comments and add them to AST
+	Trace                                          // print a trace of parsed productions
+	DeclarationErrors                              // report declaration errors
+	SpuriousErrors                                 // same as AllErrors, for backward-compatibility
+	AllErrors         = SpuriousErrors             // report all errors (not just the first 10 on different lines)
+)
+
+// ParseFile parses the source code of a single Go source file and returns
+// the corresponding ast.File node. The source code may be provided via
+// the filename of the source file, or via the src parameter.
+//
+// If src != nil, ParseFile parses the source from src and the filename is
+// only used when recording position information. The type of the argument
+// for the src parameter must be string, []byte, or io.Reader.
+// If src == nil, ParseFile parses the file specified by filename.
+//
+// The mode parameter controls the amount of source text parsed and other
+// optional parser functionality. Position information is recorded in the
+// file set fset.
+//
+// If the source couldn't be read, the returned AST is nil and the error
+// indicates the specific failure. If the source was read but syntax
+// errors were found, the result is a partial AST (with ast.Bad* nodes
+// representing the fragments of erroneous source code). Multiple errors
+// are returned via a scanner.ErrorList which is sorted by file position.
+//
+func ParseFile(fset *token.FileSet, filename string, src interface{}, mode Mode) (f *ast.File, err error) {
+	// get source
+	text, err := readSource(filename, src)
+	if err != nil {
+		return nil, err
+	}
+
+	var p parser
+	defer func() {
+		if e := recover(); e != nil {
+			_ = e.(bailout) // re-panics if it's not a bailout
+		}
+
+		// set result values
+		if f == nil {
+			// source is not a valid Go source file - satisfy
+			// ParseFile API and return a valid (but) empty
+			// *ast.File
+			f = &ast.File{
+				Name:  new(ast.Ident),
+				Scope: ast.NewScope(nil),
+			}
+		}
+
+		p.errors.Sort()
+		err = p.errors.Err()
+	}()
+
+	// parse source
+	p.init(fset, filename, text, mode)
+	f = p.parseFile()
+
+	return
+}
+
+// ParseDir calls ParseFile for all files with names ending in ".go" in the
+// directory specified by path and returns a map of package name -> package
+// AST with all the packages found.
+//
+// If filter != nil, only the files with os.FileInfo entries passing through
+// the filter (and ending in ".go") are considered. The mode bits are passed
+// to ParseFile unchanged. Position information is recorded in fset.
+//
+// If the directory couldn't be read, a nil map and the respective error are
+// returned. If a parse error occurred, a non-nil but incomplete map and the
+// first error encountered are returned.
+//
+func ParseDir(fset *token.FileSet, path string, filter func(os.FileInfo) bool, mode Mode) (pkgs map[string]*ast.Package, first error) {
+	fd, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer fd.Close()
+
+	list, err := fd.Readdir(-1)
+	if err != nil {
+		return nil, err
+	}
+
+	pkgs = make(map[string]*ast.Package)
+	for _, d := range list {
+		if strings.HasSuffix(d.Name(), ".go") && (filter == nil || filter(d)) {
+			filename := filepath.Join(path, d.Name())
+			if src, err := ParseFile(fset, filename, nil, mode); err == nil {
+				name := src.Name.Name
+				pkg, found := pkgs[name]
+				if !found {
+					pkg = &ast.Package{
+						Name:  name,
+						Files: make(map[string]*ast.File),
+					}
+					pkgs[name] = pkg
+				}
+				pkg.Files[filename] = src
+			} else if first == nil {
+				first = err
+			}
+		}
+	}
+
+	return
+}
+
+// ParseExpr is a convenience function for obtaining the AST of an expression x.
+// The position information recorded in the AST is undefined. The filename used
+// in error messages is the empty string.
+//
+func ParseExpr(x string) (ast.Expr, error) {
+	var p parser
+	p.init(token.NewFileSet(), "", []byte(x), 0)
+
+	// Set up pkg-level scopes to avoid nil-pointer errors.
+	// This is not needed for a correct expression x as the
+	// parser will be ok with a nil topScope, but be cautious
+	// in case of an erroneous x.
+	p.openScope()
+	p.pkgScope = p.topScope
+	e := p.parseRhsOrType()
+	p.closeScope()
+	assert(p.topScope == nil, "unbalanced scopes")
+
+	// If a semicolon was inserted, consume it;
+	// report an error if there's more tokens.
+	if p.tok == token.SEMICOLON && p.lit == "\n" {
+		p.next()
+	}
+	p.expect(token.EOF)
+
+	if p.errors.Len() > 0 {
+		p.errors.Sort()
+		return nil, p.errors.Err()
+	}
+
+	return e, nil
+}