vendor: add sourcegraph/s3cache and dependencies

Adds:
 - github.com/kr/http/transport
 - github.com/sqs/s3
 - github.com/sqs/s3/s3util
 - sourcegraph.com/sourcegraph/s3cache

vendor/github.com/sqs/s3/s3util/readdir.go

@@ -0,0 +1,218 @@
+package s3util
+
+import (
+	"bytes"
+	"encoding/xml"
+	"errors"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// File represents an S3 object or directory.
+type File struct {
+	url    string
+	prefix string
+	config *Config
+	result *listObjectsResult
+}
+
+type fileInfo struct {
+	name    string
+	size    int64
+	dir     bool
+	modTime time.Time
+	sys     *Stat
+}
+
+// Stat contains information about an S3 object or directory.
+// It is the "underlying data source" returned by method Sys
+// for each FileInfo produced by this package.
+//   fi.Sys().(*s3util.Stat)
+// For the meaning of these fields, see
+// http://docs.aws.amazon.com/AmazonS3/latest/API/RESTBucketGET.html.
+type Stat struct {
+	Key          string
+	LastModified string
+	ETag         string // ETag value, without double quotes.
+	Size         string
+	StorageClass string
+	OwnerID      string `xml:"Owner>ID"`
+	OwnerName    string `xml:"Owner>DisplayName"`
+}
+
+type listObjectsResult struct {
+	IsTruncated bool
+	Contents    []Stat
+	Directories []string `xml:"CommonPrefixes>Prefix"` // Suffix "/" trimmed
+}
+
+func (f *fileInfo) Name() string { return f.name }
+func (f *fileInfo) Size() int64  { return f.size }
+func (f *fileInfo) Mode() os.FileMode {
+	if f.dir {
+		return 0755 | os.ModeDir
+	}
+	return 0644
+}
+func (f *fileInfo) ModTime() time.Time {
+	if f.modTime.IsZero() && f.sys != nil {
+		// we return the zero value if a parse error ever happens.
+		f.modTime, _ = time.Parse(time.RFC3339Nano, f.sys.LastModified)
+	}
+	return f.modTime
+}
+func (f *fileInfo) IsDir() bool      { return f.dir }
+func (f *fileInfo) Sys() interface{} { return f.sys }
+
+// NewFile returns a new File with the given URL and config.
+//
+// Set rawurl to a directory on S3, such as
+// https://mybucket.s3.amazonaws.com/myfolder.
+// The URL cannot have query parameters or a fragment.
+// If c is nil, DefaultConfig will be used.
+func NewFile(rawurl string, c *Config) (*File, error) {
+	u, err := url.Parse(rawurl)
+	if err != nil {
+		return nil, err
+	}
+	if u.RawQuery != "" {
+		return nil, errors.New("url cannot have raw query parameters.")
+	}
+	if u.Fragment != "" {
+		return nil, errors.New("url cannot have a fragment.")
+	}
+
+	prefix := strings.TrimLeft(u.Path, "/")
+	if prefix != "" && !strings.HasSuffix(prefix, "/") {
+		prefix += "/"
+	}
+	u.Path = ""
+	return &File{u.String(), prefix, c, nil}, nil
+}
+
+// Readdir requests a list of entries in the S3 directory
+// represented by f and returns a slice of up to n FileInfo
+// values, in alphabetical order. Subsequent calls
+// on the same File will yield further FileInfos.
+// Only direct children are returned, not deeper descendants.
+func (f *File) Readdir(n int) ([]os.FileInfo, error) {
+	if f.result != nil && !f.result.IsTruncated {
+		return make([]os.FileInfo, 0), io.EOF
+	}
+
+	reader, err := f.sendRequest(n)
+	if err != nil {
+		return nil, err
+	}
+	defer reader.Close()
+
+	return f.parseResponse(reader)
+}
+
+func (f *File) sendRequest(count int) (io.ReadCloser, error) {
+	c := f.config
+	if c == nil {
+		c = DefaultConfig
+	}
+	var buf bytes.Buffer
+	buf.WriteString(f.url)
+	buf.WriteString("?delimiter=%2F")
+	if f.prefix != "" {
+		buf.WriteString("&prefix=")
+		buf.WriteString(url.QueryEscape(f.prefix))
+	}
+	if count > 0 {
+		buf.WriteString("&max-keys=")
+		buf.WriteString(strconv.Itoa(count))
+	}
+	if f.result != nil && f.result.IsTruncated {
+		var lastDir, lastKey, marker string
+		if len(f.result.Directories) > 0 {
+			lastDir = f.result.Directories[len(f.result.Directories)-1]
+		}
+		if len(f.result.Contents) > 0 {
+			lastKey = f.result.Contents[len(f.result.Contents)-1].Key
+		}
+
+		if lastKey > lastDir {
+			marker = lastKey
+		} else {
+			marker = lastDir
+		}
+
+		if marker != "" {
+			buf.WriteString("&marker=")
+			buf.WriteString(url.QueryEscape(marker))
+		}
+	}
+	u := buf.String()
+	r, _ := http.NewRequest("GET", u, nil)
+	r.Header.Set("Date", time.Now().UTC().Format(http.TimeFormat))
+	c.Sign(r, *c.Keys)
+	client := c.Client
+	if client == nil {
+		client = http.DefaultClient
+	}
+	resp, err := client.Do(r)
+	if err != nil {
+		return nil, err
+	}
+	if resp.StatusCode != 200 {
+		return nil, newRespError(resp)
+	}
+	return resp.Body, nil
+}
+
+func (f *File) parseResponse(reader io.Reader) ([]os.FileInfo, error) {
+	// Reading it all in now makes the XML decoding way faster.
+	bb, err := ioutil.ReadAll(reader)
+	if err != nil {
+		return nil, err
+	}
+	reader = bytes.NewReader(bb)
+
+	decoder := xml.NewDecoder(reader)
+	result := listObjectsResult{}
+	if err := decoder.Decode(&result); err != nil {
+		return nil, err
+	}
+
+	infos := make([]os.FileInfo, len(result.Contents)+len(result.Directories))
+	var size int64
+	var name string
+	var is_dir bool
+	for i, content := range result.Contents {
+		c := content
+		c.ETag = strings.Trim(c.ETag, `"`)
+		size, _ = strconv.ParseInt(c.Size, 10, 0)
+		if size == 0 && strings.HasSuffix(c.Key, "/") {
+			name = strings.TrimRight(c.Key, "/")
+			is_dir = true
+		} else {
+			name = c.Key
+			is_dir = false
+		}
+		infos[i] = &fileInfo{
+			name: name,
+			size: size,
+			dir:  is_dir,
+			sys:  &c,
+		}
+	}
+	for i, dir := range result.Directories {
+		infos[len(result.Contents)+i] = &fileInfo{
+			name: strings.TrimRight(dir, "/"),
+			size: 0,
+			dir:  true,
+		}
+	}
+	f.result = &result
+
+	return infos, nil
+}