From 554fd8c5195424bdbcabf5de30fdc183aba391bd Mon Sep 17 00:00:00 2001 From: upstream source tree Date: Sun, 15 Mar 2015 20:14:05 -0400 Subject: obtained gcc-4.6.4.tar.bz2 from upstream website; verified gcc-4.6.4.tar.bz2.sig; imported gcc-4.6.4 source tree from verified upstream tarball. downloading a git-generated archive based on the 'upstream' tag should provide you with a source tree that is binary identical to the one extracted from the above tarball. if you have obtained the source via the command 'git clone', however, do note that line-endings of files in your working directory might differ from line-endings of the respective files in the upstream repository. --- libgo/go/http/transfer.go | 441 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 441 insertions(+) create mode 100644 libgo/go/http/transfer.go (limited to 'libgo/go/http/transfer.go') diff --git a/libgo/go/http/transfer.go b/libgo/go/http/transfer.go new file mode 100644 index 000000000..e62885d62 --- /dev/null +++ b/libgo/go/http/transfer.go @@ -0,0 +1,441 @@ +// 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. + +package http + +import ( + "bufio" + "io" + "os" + "strconv" + "strings" +) + +// transferWriter inspects the fields of a user-supplied Request or Response, +// sanitizes them without changing the user object and provides methods for +// writing the respective header, body and trailer in wire format. +type transferWriter struct { + Body io.ReadCloser + ResponseToHEAD bool + ContentLength int64 + Close bool + TransferEncoding []string + Trailer map[string]string +} + +func newTransferWriter(r interface{}) (t *transferWriter, err os.Error) { + t = &transferWriter{} + + // Extract relevant fields + atLeastHTTP11 := false + switch rr := r.(type) { + case *Request: + t.Body = rr.Body + t.ContentLength = rr.ContentLength + t.Close = rr.Close + t.TransferEncoding = rr.TransferEncoding + t.Trailer = rr.Trailer + atLeastHTTP11 = rr.ProtoAtLeast(1, 1) + case *Response: + t.Body = rr.Body + t.ContentLength = rr.ContentLength + t.Close = rr.Close + t.TransferEncoding = rr.TransferEncoding + t.Trailer = rr.Trailer + atLeastHTTP11 = rr.ProtoAtLeast(1, 1) + t.ResponseToHEAD = noBodyExpected(rr.RequestMethod) + } + + // Sanitize Body,ContentLength,TransferEncoding + if t.ResponseToHEAD { + t.Body = nil + t.TransferEncoding = nil + // ContentLength is expected to hold Content-Length + if t.ContentLength < 0 { + return nil, ErrMissingContentLength + } + } else { + if !atLeastHTTP11 || t.Body == nil { + t.TransferEncoding = nil + } + if chunked(t.TransferEncoding) { + t.ContentLength = -1 + } else if t.Body == nil { // no chunking, no body + t.ContentLength = 0 + } + } + + // Sanitize Trailer + if !chunked(t.TransferEncoding) { + t.Trailer = nil + } + + return t, nil +} + +func noBodyExpected(requestMethod string) bool { + return requestMethod == "HEAD" +} + +func (t *transferWriter) WriteHeader(w io.Writer) (err os.Error) { + if t.Close { + _, err = io.WriteString(w, "Connection: close\r\n") + if err != nil { + return + } + } + + // Write Content-Length and/or Transfer-Encoding whose values are a + // function of the sanitized field triple (Body, ContentLength, + // TransferEncoding) + if chunked(t.TransferEncoding) { + _, err = io.WriteString(w, "Transfer-Encoding: chunked\r\n") + if err != nil { + return + } + } else if t.ContentLength > 0 || t.ResponseToHEAD { + io.WriteString(w, "Content-Length: ") + _, err = io.WriteString(w, strconv.Itoa64(t.ContentLength)+"\r\n") + if err != nil { + return + } + } + + // Write Trailer header + if t.Trailer != nil { + // TODO: At some point, there should be a generic mechanism for + // writing long headers, using HTTP line splitting + io.WriteString(w, "Trailer: ") + needComma := false + for k := range t.Trailer { + k = CanonicalHeaderKey(k) + switch k { + case "Transfer-Encoding", "Trailer", "Content-Length": + return &badStringError{"invalid Trailer key", k} + } + if needComma { + io.WriteString(w, ",") + } + io.WriteString(w, k) + needComma = true + } + _, err = io.WriteString(w, "\r\n") + } + + return +} + +func (t *transferWriter) WriteBody(w io.Writer) (err os.Error) { + // Write body + if t.Body != nil { + if chunked(t.TransferEncoding) { + cw := NewChunkedWriter(w) + _, err = io.Copy(cw, t.Body) + if err == nil { + err = cw.Close() + } + } else if t.ContentLength == -1 { + _, err = io.Copy(w, t.Body) + } else { + _, err = io.Copy(w, io.LimitReader(t.Body, t.ContentLength)) + } + if err != nil { + return err + } + if err = t.Body.Close(); err != nil { + return err + } + } + + // TODO(petar): Place trailer writer code here. + if chunked(t.TransferEncoding) { + // Last chunk, empty trailer + _, err = io.WriteString(w, "\r\n") + } + + return +} + +type transferReader struct { + // Input + Header map[string]string + StatusCode int + RequestMethod string + ProtoMajor int + ProtoMinor int + // Output + Body io.ReadCloser + ContentLength int64 + TransferEncoding []string + Close bool + Trailer map[string]string +} + +// msg is *Request or *Response. +func readTransfer(msg interface{}, r *bufio.Reader) (err os.Error) { + t := &transferReader{} + + // Unify input + switch rr := msg.(type) { + case *Response: + t.Header = rr.Header + t.StatusCode = rr.StatusCode + t.RequestMethod = rr.RequestMethod + t.ProtoMajor = rr.ProtoMajor + t.ProtoMinor = rr.ProtoMinor + t.Close = shouldClose(t.ProtoMajor, t.ProtoMinor, t.Header) + case *Request: + t.Header = rr.Header + t.ProtoMajor = rr.ProtoMajor + t.ProtoMinor = rr.ProtoMinor + // Transfer semantics for Requests are exactly like those for + // Responses with status code 200, responding to a GET method + t.StatusCode = 200 + t.RequestMethod = "GET" + } + + // Default to HTTP/1.1 + if t.ProtoMajor == 0 && t.ProtoMinor == 0 { + t.ProtoMajor, t.ProtoMinor = 1, 1 + } + + // Transfer encoding, content length + t.TransferEncoding, err = fixTransferEncoding(t.Header) + if err != nil { + return err + } + + t.ContentLength, err = fixLength(t.StatusCode, t.RequestMethod, t.Header, t.TransferEncoding) + if err != nil { + return err + } + + // Trailer + t.Trailer, err = fixTrailer(t.Header, t.TransferEncoding) + if err != nil { + return err + } + + // Prepare body reader. ContentLength < 0 means chunked encoding + // or close connection when finished, since multipart is not supported yet + switch { + case chunked(t.TransferEncoding): + t.Body = &body{Reader: newChunkedReader(r), hdr: msg, r: r, closing: t.Close} + case t.ContentLength >= 0: + // TODO: limit the Content-Length. This is an easy DoS vector. + t.Body = &body{Reader: io.LimitReader(r, t.ContentLength), closing: t.Close} + default: + // t.ContentLength < 0, i.e. "Content-Length" not mentioned in header + if t.Close { + // Close semantics (i.e. HTTP/1.0) + t.Body = &body{Reader: r, closing: t.Close} + } else { + // Persistent connection (i.e. HTTP/1.1) + t.Body = &body{Reader: io.LimitReader(r, 0), closing: t.Close} + } + // TODO(petar): It may be a good idea, for extra robustness, to + // assume ContentLength=0 for GET requests (and other special + // cases?). This logic should be in fixLength(). + } + + // Unify output + switch rr := msg.(type) { + case *Request: + rr.Body = t.Body + rr.ContentLength = t.ContentLength + rr.TransferEncoding = t.TransferEncoding + rr.Close = t.Close + rr.Trailer = t.Trailer + case *Response: + rr.Body = t.Body + rr.ContentLength = t.ContentLength + rr.TransferEncoding = t.TransferEncoding + rr.Close = t.Close + rr.Trailer = t.Trailer + } + + return nil +} + +// Checks whether chunked is part of the encodings stack +func chunked(te []string) bool { return len(te) > 0 && te[0] == "chunked" } + +// Sanitize transfer encoding +func fixTransferEncoding(header map[string]string) ([]string, os.Error) { + raw, present := header["Transfer-Encoding"] + if !present { + return nil, nil + } + + header["Transfer-Encoding"] = "", false + encodings := strings.Split(raw, ",", -1) + te := make([]string, 0, len(encodings)) + // TODO: Even though we only support "identity" and "chunked" + // encodings, the loop below is designed with foresight. One + // invariant that must be maintained is that, if present, + // chunked encoding must always come first. + for _, encoding := range encodings { + encoding = strings.ToLower(strings.TrimSpace(encoding)) + // "identity" encoding is not recored + if encoding == "identity" { + break + } + if encoding != "chunked" { + return nil, &badStringError{"unsupported transfer encoding", encoding} + } + te = te[0 : len(te)+1] + te[len(te)-1] = encoding + } + if len(te) > 1 { + return nil, &badStringError{"too many transfer encodings", strings.Join(te, ",")} + } + if len(te) > 0 { + // Chunked encoding trumps Content-Length. See RFC 2616 + // Section 4.4. Currently len(te) > 0 implies chunked + // encoding. + header["Content-Length"] = "", false + return te, nil + } + + return nil, nil +} + +// Determine the expected body length, using RFC 2616 Section 4.4. This +// function is not a method, because ultimately it should be shared by +// ReadResponse and ReadRequest. +func fixLength(status int, requestMethod string, header map[string]string, te []string) (int64, os.Error) { + + // Logic based on response type or status + if noBodyExpected(requestMethod) { + return 0, nil + } + if status/100 == 1 { + return 0, nil + } + switch status { + case 204, 304: + return 0, nil + } + + // Logic based on Transfer-Encoding + if chunked(te) { + return -1, nil + } + + // Logic based on Content-Length + if cl, present := header["Content-Length"]; present { + cl = strings.TrimSpace(cl) + if cl != "" { + n, err := strconv.Atoi64(cl) + if err != nil || n < 0 { + return -1, &badStringError{"bad Content-Length", cl} + } + return n, nil + } else { + header["Content-Length"] = "", false + } + } + + // Logic based on media type. The purpose of the following code is just + // to detect whether the unsupported "multipart/byteranges" is being + // used. A proper Content-Type parser is needed in the future. + if strings.Contains(strings.ToLower(header["Content-Type"]), "multipart/byteranges") { + return -1, ErrNotSupported + } + + // Body-EOF logic based on other methods (like closing, or chunked coding) + return -1, nil +} + +// Determine whether to hang up after sending a request and body, or +// receiving a response and body +// 'header' is the request headers +func shouldClose(major, minor int, header map[string]string) bool { + if major < 1 { + return true + } else if major == 1 && minor == 0 { + v, present := header["Connection"] + if !present { + return true + } + v = strings.ToLower(v) + if !strings.Contains(v, "keep-alive") { + return true + } + return false + } else if v, present := header["Connection"]; present { + // TODO: Should split on commas, toss surrounding white space, + // and check each field. + if v == "close" { + header["Connection"] = "", false + return true + } + } + return false +} + +// Parse the trailer header +func fixTrailer(header map[string]string, te []string) (map[string]string, os.Error) { + raw, present := header["Trailer"] + if !present { + return nil, nil + } + + header["Trailer"] = "", false + trailer := make(map[string]string) + keys := strings.Split(raw, ",", -1) + for _, key := range keys { + key = CanonicalHeaderKey(strings.TrimSpace(key)) + switch key { + case "Transfer-Encoding", "Trailer", "Content-Length": + return nil, &badStringError{"bad trailer key", key} + } + trailer[key] = "" + } + if len(trailer) == 0 { + return nil, nil + } + if !chunked(te) { + // Trailer and no chunking + return nil, ErrUnexpectedTrailer + } + return trailer, nil +} + +// body turns a Reader into a ReadCloser. +// Close ensures that the body has been fully read +// and then reads the trailer if necessary. +type body struct { + io.Reader + hdr interface{} // non-nil (Response or Request) value means read trailer + r *bufio.Reader // underlying wire-format reader for the trailer + closing bool // is the connection to be closed after reading body? +} + +func (b *body) Close() os.Error { + if b.hdr == nil && b.closing { + // no trailer and closing the connection next. + // no point in reading to EOF. + return nil + } + + trashBuf := make([]byte, 1024) // local for thread safety + for { + _, err := b.Read(trashBuf) + if err == nil { + continue + } + if err == os.EOF { + break + } + return err + } + if b.hdr == nil { // not reading trailer + return nil + } + + // TODO(petar): Put trailer reader code here + + return nil +} -- cgit v1.2.3