mirror of
https://github.com/vbatts/go-mtree.git
synced 2024-11-05 00:15:58 +00:00
283 lines
9.7 KiB
Go
283 lines
9.7 KiB
Go
package mtree
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import (
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"archive/tar"
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"crypto/md5"
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"crypto/sha1"
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"crypto/sha256"
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"crypto/sha512"
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"fmt"
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"hash"
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"io"
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"os"
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"strings"
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"golang.org/x/crypto/ripemd160"
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)
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// KeywordFunc is the type of a function called on each file to be included in
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// a DirectoryHierarchy, that will produce the string output of the keyword to
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// be included for the file entry. Otherwise, empty string.
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// io.Reader `r` is to the file stream for the file payload. While this
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// function takes an io.Reader, the caller needs to reset it to the beginning
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// for each new KeywordFunc
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type KeywordFunc func(path string, info os.FileInfo, r io.Reader) (string, error)
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// KeyVal is a "keyword=value"
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type KeyVal string
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// Keyword is the mapping to the available keywords
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func (kv KeyVal) Keyword() string {
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if !strings.Contains(string(kv), "=") {
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return ""
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}
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chunks := strings.SplitN(strings.TrimSpace(string(kv)), "=", 2)[0]
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if !strings.Contains(chunks, ".") {
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return chunks
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}
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return strings.SplitN(chunks, ".", 2)[0]
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}
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// KeywordSuffix is really only used for xattr, as the keyword is a prefix to
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// the xattr "namespace.key"
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func (kv KeyVal) KeywordSuffix() string {
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if !strings.Contains(string(kv), "=") {
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return ""
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}
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chunks := strings.SplitN(strings.TrimSpace(string(kv)), "=", 2)[0]
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if !strings.Contains(chunks, ".") {
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return ""
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}
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return strings.SplitN(chunks, ".", 2)[1]
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}
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// Value is the data/value portion of "keyword=value"
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func (kv KeyVal) Value() string {
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if !strings.Contains(string(kv), "=") {
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return ""
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}
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return strings.SplitN(strings.TrimSpace(string(kv)), "=", 2)[1]
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}
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// ChangeValue changes the value of a KeyVal
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func (kv KeyVal) ChangeValue(newval string) string {
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return fmt.Sprintf("%s=%s", kv.Keyword(), newval)
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}
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// keywordSelector takes an array of "keyword=value" and filters out that only the set of words
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func keywordSelector(keyval, words []string) []string {
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retList := []string{}
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for _, kv := range keyval {
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if inSlice(KeyVal(kv).Keyword(), words) {
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retList = append(retList, kv)
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}
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}
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return retList
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}
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// NewKeyVals constructs a list of KeyVal from the list of strings, like "keyword=value"
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func NewKeyVals(keyvals []string) KeyVals {
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kvs := make(KeyVals, len(keyvals))
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for i := range keyvals {
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kvs[i] = KeyVal(keyvals[i])
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}
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return kvs
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}
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// KeyVals is a list of KeyVal
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type KeyVals []KeyVal
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// Has the "keyword" present in the list of KeyVal, and returns the
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// corresponding KeyVal, else an empty string.
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func (kvs KeyVals) Has(keyword string) KeyVal {
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for i := range kvs {
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if kvs[i].Keyword() == keyword {
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return kvs[i]
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}
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}
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return emptyKV
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}
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var emptyKV = KeyVal("")
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// MergeSet takes the current setKeyVals, and then applies the entryKeyVals
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// such that the entry's values win. The union is returned.
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func MergeSet(setKeyVals, entryKeyVals []string) KeyVals {
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retList := NewKeyVals(append([]string{}, setKeyVals...))
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eKVs := NewKeyVals(entryKeyVals)
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seenKeywords := []string{}
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for i := range retList {
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word := retList[i].Keyword()
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if ekv := eKVs.Has(word); ekv != emptyKV {
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retList[i] = ekv
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}
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seenKeywords = append(seenKeywords, word)
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}
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for i := range eKVs {
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if !inSlice(eKVs[i].Keyword(), seenKeywords) {
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retList = append(retList, eKVs[i])
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}
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}
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return retList
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}
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var (
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// DefaultKeywords has the several default keyword producers (uid, gid,
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// mode, nlink, type, size, mtime)
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DefaultKeywords = []string{
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"size",
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"type",
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"uid",
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"gid",
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"mode",
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"link",
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"nlink",
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"time",
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}
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// DefaultTarKeywords has keywords that should be used when creating a manifest from
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// an archive. Currently, evaluating the # of hardlinks has not been implemented yet
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DefaultTarKeywords = []string{
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"size",
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"type",
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"uid",
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"gid",
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"mode",
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"link",
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"tar_time",
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}
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// SetKeywords is the default set of keywords calculated for a `/set` SpecialType
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SetKeywords = []string{
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"uid",
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"gid",
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}
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// KeywordFuncs is the map of all keywords (and the functions to produce them)
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KeywordFuncs = map[string]KeywordFunc{
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"size": sizeKeywordFunc, // The size, in bytes, of the file
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"type": typeKeywordFunc, // The type of the file
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"time": timeKeywordFunc, // The last modification time of the file
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"link": linkKeywordFunc, // The target of the symbolic link when type=link
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"uid": uidKeywordFunc, // The file owner as a numeric value
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"gid": gidKeywordFunc, // The file group as a numeric value
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"nlink": nlinkKeywordFunc, // The number of hard links the file is expected to have
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"uname": unameKeywordFunc, // The file owner as a symbolic name
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"mode": modeKeywordFunc, // The current file's permissions as a numeric (octal) or symbolic value
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"cksum": cksumKeywordFunc, // The checksum of the file using the default algorithm specified by the cksum(1) utility
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"md5": hasherKeywordFunc("md5", md5.New), // The MD5 message digest of the file
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"md5digest": hasherKeywordFunc("md5digest", md5.New), // A synonym for `md5`
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"rmd160": hasherKeywordFunc("rmd160", ripemd160.New), // The RIPEMD160 message digest of the file
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"rmd160digest": hasherKeywordFunc("rmd160digest", ripemd160.New), // A synonym for `rmd160`
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"ripemd160digest": hasherKeywordFunc("ripemd160digest", ripemd160.New), // A synonym for `rmd160`
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"sha1": hasherKeywordFunc("sha1", sha1.New), // The SHA1 message digest of the file
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"sha1digest": hasherKeywordFunc("sha1digest", sha1.New), // A synonym for `sha1`
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"sha256": hasherKeywordFunc("sha256", sha256.New), // The SHA256 message digest of the file
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"sha256digest": hasherKeywordFunc("sha256digest", sha256.New), // A synonym for `sha256`
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"sha384": hasherKeywordFunc("sha384", sha512.New384), // The SHA384 message digest of the file
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"sha384digest": hasherKeywordFunc("sha384digest", sha512.New384), // A synonym for `sha384`
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"sha512": hasherKeywordFunc("sha512", sha512.New), // The SHA512 message digest of the file
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"sha512digest": hasherKeywordFunc("sha512digest", sha512.New), // A synonym for `sha512`
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// This is not an upstreamed keyword, but used to vary from "time", as tar
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// archives do not store nanosecond precision. So comparing on "time" will
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// be only seconds level accurate.
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"tar_time": tartimeKeywordFunc, // The last modification time of the file, from a tar archive mtime
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// This is not an upstreamed keyword, but a needed attribute for file validation.
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// The pattern for this keyword key is prefixed by "xattr." followed by the extended attribute "namespace.key".
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// The keyword value is the SHA1 digest of the extended attribute's value.
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// In this way, the order of the keys does not matter, and the contents of the value is not revealed.
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"xattr": xattrKeywordFunc,
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"xattrs": xattrKeywordFunc,
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}
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)
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var (
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modeKeywordFunc = func(path string, info os.FileInfo, r io.Reader) (string, error) {
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permissions := info.Mode().Perm()
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if os.ModeSetuid&info.Mode() > 0 {
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permissions |= (1 << 11)
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}
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if os.ModeSetgid&info.Mode() > 0 {
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permissions |= (1 << 10)
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}
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if os.ModeSticky&info.Mode() > 0 {
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permissions |= (1 << 9)
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}
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return fmt.Sprintf("mode=%#o", permissions), nil
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}
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sizeKeywordFunc = func(path string, info os.FileInfo, r io.Reader) (string, error) {
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return fmt.Sprintf("size=%d", info.Size()), nil
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}
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cksumKeywordFunc = func(path string, info os.FileInfo, r io.Reader) (string, error) {
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if !info.Mode().IsRegular() {
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return "", nil
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}
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sum, _, err := cksum(r)
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if err != nil {
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return "", err
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}
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return fmt.Sprintf("cksum=%d", sum), nil
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}
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hasherKeywordFunc = func(name string, newHash func() hash.Hash) KeywordFunc {
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return func(path string, info os.FileInfo, r io.Reader) (string, error) {
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if !info.Mode().IsRegular() {
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return "", nil
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}
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h := newHash()
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if _, err := io.Copy(h, r); err != nil {
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return "", err
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}
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return fmt.Sprintf("%s=%x", name, h.Sum(nil)), nil
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}
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}
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tartimeKeywordFunc = func(path string, info os.FileInfo, r io.Reader) (string, error) {
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return fmt.Sprintf("tar_time=%d.000000000", info.ModTime().Unix()), nil
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}
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timeKeywordFunc = func(path string, info os.FileInfo, r io.Reader) (string, error) {
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t := info.ModTime().UnixNano()
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if t == 0 {
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return "time=0.000000000", nil
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}
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return fmt.Sprintf("time=%d.%9.9d", (t / 1e9), (t % (t / 1e9))), nil
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}
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linkKeywordFunc = func(path string, info os.FileInfo, r io.Reader) (string, error) {
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if sys, ok := info.Sys().(*tar.Header); ok {
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if sys.Linkname != "" {
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return fmt.Sprintf("link=%s", sys.Linkname), nil
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}
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return "", nil
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}
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if info.Mode()&os.ModeSymlink != 0 {
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str, err := os.Readlink(path)
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if err != nil {
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return "", err
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}
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return fmt.Sprintf("link=%s", str), nil
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}
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return "", nil
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}
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typeKeywordFunc = func(path string, info os.FileInfo, r io.Reader) (string, error) {
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if info.Mode().IsDir() {
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return "type=dir", nil
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}
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if info.Mode().IsRegular() {
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return "type=file", nil
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}
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if info.Mode()&os.ModeSocket != 0 {
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return "type=socket", nil
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}
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if info.Mode()&os.ModeSymlink != 0 {
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return "type=link", nil
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}
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if info.Mode()&os.ModeNamedPipe != 0 {
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return "type=fifo", nil
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}
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if info.Mode()&os.ModeDevice != 0 {
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if info.Mode()&os.ModeCharDevice != 0 {
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return "type=char", nil
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}
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return "type=device", nil
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}
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return "", nil
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}
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)
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