1 files changed, 280 insertions, 0 deletions
diff --git a/libgo/go/mime/multipart/multipart.go b/libgo/go/mime/multipart/multipart.go
new file mode 100644
index 000000000..1d855c74c
--- /dev/null
+++ b/libgo/go/mime/multipart/multipart.go
@@ -0,0 +1,280 @@
+// Copyright 2010 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.
+//
+
+/*
+Package multipart implements MIME multipart parsing, as defined in RFC
+2046.
+
+The implementation is sufficient for HTTP (RFC 2388) and the multipart
+bodies generated by popular browsers.
+*/
+package multipart
+
+import (
+	"bufio"
+	"bytes"
+	"io"
+	"mime"
+	"os"
+	"regexp"
+	"strings"
+)
+
+var headerRegexp *regexp.Regexp = regexp.MustCompile("^([a-zA-Z0-9\\-]+): *([^\r\n]+)")
+
+// Reader is an iterator over parts in a MIME multipart body.
+// Reader's underlying parser consumes its input as needed.  Seeking
+// isn't supported.
+type Reader interface {
+	// NextPart returns the next part in the multipart, or (nil,
+	// nil) on EOF.  An error is returned if the underlying reader
+	// reports errors, or on truncated or otherwise malformed
+	// input.
+	NextPart() (*Part, os.Error)
+}
+
+// A Part represents a single part in a multipart body.
+type Part struct {
+	// The headers of the body, if any, with the keys canonicalized
+	// in the same fashion that the Go http.Request headers are.
+	// i.e. "foo-bar" changes case to "Foo-Bar"
+	Header map[string]string
+
+	buffer *bytes.Buffer
+	mr     *multiReader
+}
+
+// FormName returns the name parameter if p has a Content-Disposition
+// of type "form-data".  Otherwise it returns the empty string.
+func (p *Part) FormName() string {
+	// See http://tools.ietf.org/html/rfc2183 section 2 for EBNF
+	// of Content-Disposition value format.
+	v, ok := p.Header["Content-Disposition"]
+	if !ok {
+		return ""
+	}
+	d, params := mime.ParseMediaType(v)
+	if d != "form-data" {
+		return ""
+	}
+	return params["name"]
+}
+
+// NewReader creates a new multipart Reader reading from r using the
+// given MIME boundary.
+func NewReader(reader io.Reader, boundary string) Reader {
+	return &multiReader{
+		boundary:     boundary,
+		dashBoundary: "--" + boundary,
+		endLine:      "--" + boundary + "--",
+		bufReader:    bufio.NewReader(reader),
+	}
+}
+
+// Implementation ....
+
+type devNullWriter bool
+
+func (*devNullWriter) Write(p []byte) (n int, err os.Error) {
+	return len(p), nil
+}
+
+var devNull = devNullWriter(false)
+
+func newPart(mr *multiReader) (bp *Part, err os.Error) {
+	bp = new(Part)
+	bp.Header = make(map[string]string)
+	bp.mr = mr
+	bp.buffer = new(bytes.Buffer)
+	if err = bp.populateHeaders(); err != nil {
+		bp = nil
+	}
+	return
+}
+
+func (bp *Part) populateHeaders() os.Error {
+	for {
+		line, err := bp.mr.bufReader.ReadString('\n')
+		if err != nil {
+			return err
+		}
+		if line == "\n" || line == "\r\n" {
+			return nil
+		}
+		if matches := headerRegexp.FindStringSubmatch(line); len(matches) == 3 {
+			key := matches[1]
+			value := matches[2]
+			// TODO: canonicalize headers ala http.Request.Header?
+			bp.Header[key] = value
+			continue
+		}
+		return os.NewError("Unexpected header line found parsing multipart body")
+	}
+	panic("unreachable")
+}
+
+// Read reads the body of a part, after its headers and before the
+// next part (if any) begins.
+func (bp *Part) Read(p []byte) (n int, err os.Error) {
+	for {
+		if bp.buffer.Len() >= len(p) {
+			// Internal buffer of unconsumed data is large enough for
+			// the read request.  No need to parse more at the moment.
+			break
+		}
+		if !bp.mr.ensureBufferedLine() {
+			return 0, io.ErrUnexpectedEOF
+		}
+		if bp.mr.bufferedLineIsBoundary() {
+			// Don't consume this line
+			break
+		}
+
+		// Write all of this line, except the final CRLF
+		s := *bp.mr.bufferedLine
+		if strings.HasSuffix(s, "\r\n") {
+			bp.mr.consumeLine()
+			if !bp.mr.ensureBufferedLine() {
+				return 0, io.ErrUnexpectedEOF
+			}
+			if bp.mr.bufferedLineIsBoundary() {
+				// The final \r\n isn't ours.  It logically belongs
+				// to the boundary line which follows.
+				bp.buffer.WriteString(s[0 : len(s)-2])
+			} else {
+				bp.buffer.WriteString(s)
+			}
+			break
+		}
+		if strings.HasSuffix(s, "\n") {
+			bp.buffer.WriteString(s)
+			bp.mr.consumeLine()
+			continue
+		}
+		return 0, os.NewError("multipart parse error during Read; unexpected line: " + s)
+	}
+	return bp.buffer.Read(p)
+}
+
+func (bp *Part) Close() os.Error {
+	io.Copy(&devNull, bp)
+	return nil
+}
+
+type multiReader struct {
+	boundary     string
+	dashBoundary string // --boundary
+	endLine      string // --boundary--
+
+	bufferedLine *string
+
+	bufReader   *bufio.Reader
+	currentPart *Part
+	partsRead   int
+}
+
+func (mr *multiReader) eof() bool {
+	return mr.bufferedLine == nil &&
+		!mr.readLine()
+}
+
+func (mr *multiReader) readLine() bool {
+	line, err := mr.bufReader.ReadString('\n')
+	if err != nil {
+		// TODO: care about err being EOF or not?
+		return false
+	}
+	mr.bufferedLine = &line
+	return true
+}
+
+func (mr *multiReader) bufferedLineIsBoundary() bool {
+	return strings.HasPrefix(*mr.bufferedLine, mr.dashBoundary)
+}
+
+func (mr *multiReader) ensureBufferedLine() bool {
+	if mr.bufferedLine == nil {
+		return mr.readLine()
+	}
+	return true
+}
+
+func (mr *multiReader) consumeLine() {
+	mr.bufferedLine = nil
+}
+
+func (mr *multiReader) NextPart() (*Part, os.Error) {
+	if mr.currentPart != nil {
+		mr.currentPart.Close()
+	}
+
+	for {
+		if mr.eof() {
+			return nil, io.ErrUnexpectedEOF
+		}
+
+		if isBoundaryDelimiterLine(*mr.bufferedLine, mr.dashBoundary) {
+			mr.consumeLine()
+			mr.partsRead++
+			bp, err := newPart(mr)
+			if err != nil {
+				return nil, err
+			}
+			mr.currentPart = bp
+			return bp, nil
+		}
+
+		if hasPrefixThenNewline(*mr.bufferedLine, mr.endLine) {
+			mr.consumeLine()
+			// Expected EOF (no error)
+			return nil, nil
+		}
+
+		if mr.partsRead == 0 {
+			// skip line
+			mr.consumeLine()
+			continue
+		}
+
+		return nil, os.NewError("Unexpected line in Next().")
+	}
+	panic("unreachable")
+}
+
+func isBoundaryDelimiterLine(line, dashPrefix string) bool {
+	// http://tools.ietf.org/html/rfc2046#section-5.1
+	//   The boundary delimiter line is then defined as a line
+	//   consisting entirely of two hyphen characters ("-",
+	//   decimal value 45) followed by the boundary parameter
+	//   value from the Content-Type header field, optional linear
+	//   whitespace, and a terminating CRLF.
+	if !strings.HasPrefix(line, dashPrefix) {
+		return false
+	}
+	if strings.HasSuffix(line, "\r\n") {
+		return onlyHorizontalWhitespace(line[len(dashPrefix) : len(line)-2])
+	}
+	// Violate the spec and also support newlines without the
+	// carriage return...
+	if strings.HasSuffix(line, "\n") {
+		return onlyHorizontalWhitespace(line[len(dashPrefix) : len(line)-1])
+	}
+	return false
+}
+
+func onlyHorizontalWhitespace(s string) bool {
+	for i := 0; i < len(s); i++ {
+		if s[i] != ' ' && s[i] != '\t' {
+			return false
+		}
+	}
+	return true
+}
+
+func hasPrefixThenNewline(s, prefix string) bool {
+	return strings.HasPrefix(s, prefix) &&
+		(len(s) == len(prefix)+1 && strings.HasSuffix(s, "\n") ||
+			len(s) == len(prefix)+2 && strings.HasSuffix(s, "\r\n"))
+}