1 files changed, 276 insertions, 0 deletions
diff --git a/src/cmd/dist/imports.go b/src/cmd/dist/imports.go
new file mode 100644
index 0000000..05dd84d
--- /dev/null
+++ b/src/cmd/dist/imports.go
@@ -0,0 +1,276 @@
+// Copyright 2012 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 is forked from go/build/read.go.
+// (cmd/dist must not import go/build because we do not want it to be
+// sensitive to the specific version of go/build present in $GOROOT_BOOTSTRAP.)
+
+package main
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"io"
+	"path"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"unicode/utf8"
+)
+
+type importReader struct {
+	b    *bufio.Reader
+	buf  []byte
+	peek byte
+	err  error
+	eof  bool
+	nerr int
+}
+
+func isIdent(c byte) bool {
+	return 'A' <= c && c <= 'Z' || 'a' <= c && c <= 'z' || '0' <= c && c <= '9' || c == '_' || c >= utf8.RuneSelf
+}
+
+var (
+	errSyntax = errors.New("syntax error")
+	errNUL    = errors.New("unexpected NUL in input")
+)
+
+// syntaxError records a syntax error, but only if an I/O error has not already been recorded.
+func (r *importReader) syntaxError() {
+	if r.err == nil {
+		r.err = errSyntax
+	}
+}
+
+// readByte reads the next byte from the input, saves it in buf, and returns it.
+// If an error occurs, readByte records the error in r.err and returns 0.
+func (r *importReader) readByte() byte {
+	c, err := r.b.ReadByte()
+	if err == nil {
+		r.buf = append(r.buf, c)
+		if c == 0 {
+			err = errNUL
+		}
+	}
+	if err != nil {
+		if err == io.EOF {
+			r.eof = true
+		} else if r.err == nil {
+			r.err = err
+		}
+		c = 0
+	}
+	return c
+}
+
+// peekByte returns the next byte from the input reader but does not advance beyond it.
+// If skipSpace is set, peekByte skips leading spaces and comments.
+func (r *importReader) peekByte(skipSpace bool) byte {
+	if r.err != nil {
+		if r.nerr++; r.nerr > 10000 {
+			panic("go/build: import reader looping")
+		}
+		return 0
+	}
+
+	// Use r.peek as first input byte.
+	// Don't just return r.peek here: it might have been left by peekByte(false)
+	// and this might be peekByte(true).
+	c := r.peek
+	if c == 0 {
+		c = r.readByte()
+	}
+	for r.err == nil && !r.eof {
+		if skipSpace {
+			// For the purposes of this reader, semicolons are never necessary to
+			// understand the input and are treated as spaces.
+			switch c {
+			case ' ', '\f', '\t', '\r', '\n', ';':
+				c = r.readByte()
+				continue
+
+			case '/':
+				c = r.readByte()
+				if c == '/' {
+					for c != '\n' && r.err == nil && !r.eof {
+						c = r.readByte()
+					}
+				} else if c == '*' {
+					var c1 byte
+					for (c != '*' || c1 != '/') && r.err == nil {
+						if r.eof {
+							r.syntaxError()
+						}
+						c, c1 = c1, r.readByte()
+					}
+				} else {
+					r.syntaxError()
+				}
+				c = r.readByte()
+				continue
+			}
+		}
+		break
+	}
+	r.peek = c
+	return r.peek
+}
+
+// nextByte is like peekByte but advances beyond the returned byte.
+func (r *importReader) nextByte(skipSpace bool) byte {
+	c := r.peekByte(skipSpace)
+	r.peek = 0
+	return c
+}
+
+// readKeyword reads the given keyword from the input.
+// If the keyword is not present, readKeyword records a syntax error.
+func (r *importReader) readKeyword(kw string) {
+	r.peekByte(true)
+	for i := 0; i < len(kw); i++ {
+		if r.nextByte(false) != kw[i] {
+			r.syntaxError()
+			return
+		}
+	}
+	if isIdent(r.peekByte(false)) {
+		r.syntaxError()
+	}
+}
+
+// readIdent reads an identifier from the input.
+// If an identifier is not present, readIdent records a syntax error.
+func (r *importReader) readIdent() {
+	c := r.peekByte(true)
+	if !isIdent(c) {
+		r.syntaxError()
+		return
+	}
+	for isIdent(r.peekByte(false)) {
+		r.peek = 0
+	}
+}
+
+// readString reads a quoted string literal from the input.
+// If an identifier is not present, readString records a syntax error.
+func (r *importReader) readString(save *[]string) {
+	switch r.nextByte(true) {
+	case '`':
+		start := len(r.buf) - 1
+		for r.err == nil {
+			if r.nextByte(false) == '`' {
+				if save != nil {
+					*save = append(*save, string(r.buf[start:]))
+				}
+				break
+			}
+			if r.eof {
+				r.syntaxError()
+			}
+		}
+	case '"':
+		start := len(r.buf) - 1
+		for r.err == nil {
+			c := r.nextByte(false)
+			if c == '"' {
+				if save != nil {
+					*save = append(*save, string(r.buf[start:]))
+				}
+				break
+			}
+			if r.eof || c == '\n' {
+				r.syntaxError()
+			}
+			if c == '\\' {
+				r.nextByte(false)
+			}
+		}
+	default:
+		r.syntaxError()
+	}
+}
+
+// readImport reads an import clause - optional identifier followed by quoted string -
+// from the input.
+func (r *importReader) readImport(imports *[]string) {
+	c := r.peekByte(true)
+	if c == '.' {
+		r.peek = 0
+	} else if isIdent(c) {
+		r.readIdent()
+	}
+	r.readString(imports)
+}
+
+// readComments is like ioutil.ReadAll, except that it only reads the leading
+// block of comments in the file.
+func readComments(f io.Reader) ([]byte, error) {
+	r := &importReader{b: bufio.NewReader(f)}
+	r.peekByte(true)
+	if r.err == nil && !r.eof {
+		// Didn't reach EOF, so must have found a non-space byte. Remove it.
+		r.buf = r.buf[:len(r.buf)-1]
+	}
+	return r.buf, r.err
+}
+
+// readimports returns the imports found in the named file.
+func readimports(file string) []string {
+	var imports []string
+	r := &importReader{b: bufio.NewReader(strings.NewReader(readfile(file)))}
+	r.readKeyword("package")
+	r.readIdent()
+	for r.peekByte(true) == 'i' {
+		r.readKeyword("import")
+		if r.peekByte(true) == '(' {
+			r.nextByte(false)
+			for r.peekByte(true) != ')' && r.err == nil {
+				r.readImport(&imports)
+			}
+			r.nextByte(false)
+		} else {
+			r.readImport(&imports)
+		}
+	}
+
+	for i := range imports {
+		unquoted, err := strconv.Unquote(imports[i])
+		if err != nil {
+			fatalf("reading imports from %s: %v", file, err)
+		}
+		imports[i] = unquoted
+	}
+
+	return imports
+}
+
+// resolveVendor returns a unique package path imported with the given import
+// path from srcDir.
+//
+// resolveVendor assumes that a package is vendored if and only if its first
+// path component contains a dot. If a package is vendored, its import path
+// is returned with a "vendor" or "cmd/vendor" prefix, depending on srcDir.
+// Otherwise, the import path is returned verbatim.
+func resolveVendor(imp, srcDir string) string {
+	var first string
+	if i := strings.Index(imp, "/"); i < 0 {
+		first = imp
+	} else {
+		first = imp[:i]
+	}
+	isStandard := !strings.Contains(first, ".")
+	if isStandard {
+		return imp
+	}
+
+	if strings.HasPrefix(srcDir, filepath.Join(goroot, "src", "cmd")) {
+		return path.Join("cmd", "vendor", imp)
+	} else if strings.HasPrefix(srcDir, filepath.Join(goroot, "src")) {
+		return path.Join("vendor", imp)
+	} else {
+		panic(fmt.Sprintf("srcDir %q not in GOOROT/src", srcDir))
+	}
+}