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Go: less API stupidity coming from the C++ heritage

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Přemysl Eric Janouch
2018-10-04 14:46:12 +02:00
parent 9d2412398a
commit 0ea296de67
1 changed files with 20 additions and 19 deletions
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39
pdf/pdf.go
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@@ -141,21 +141,21 @@ const (
// Lexer is a basic lexical analyser for the Portable Document Format, // Lexer is a basic lexical analyser for the Portable Document Format,
// giving limited error information. // giving limited error information.
type Lexer struct { type Lexer struct {
p []byte // input buffer P []byte // input buffer
} }
func (lex *Lexer) read() (byte, bool) { func (lex *Lexer) read() (byte, bool) {
if len(lex.p) > 0 { if len(lex.P) > 0 {
ch := lex.p[0] ch := lex.P[0]
lex.p = lex.p[1:] lex.P = lex.P[1:]
return ch, true return ch, true
} }
return 0, false return 0, false
} }
func (lex *Lexer) peek() (byte, bool) { func (lex *Lexer) peek() (byte, bool) {
if len(lex.p) > 0 { if len(lex.P) > 0 {
return lex.p[0], true return lex.P[0], true
} }
return 0, false return 0, false
} }
@@ -671,9 +671,10 @@ func (u *Updater) loadXref(lex *Lexer, loadedEntries map[uint]struct{}) error {
var haystackRE = regexp.MustCompile(`(?s:.*)\sstartxref\s+(\d+)\s+%%EOF`) var haystackRE = regexp.MustCompile(`(?s:.*)\sstartxref\s+(\d+)\s+%%EOF`)
// Initialize builds the cross-reference table and prepares // NewUpdater initializes an Updater, building the cross-reference table and
// a new trailer dictionary. // preparing a new trailer dictionary.
func (u *Updater) Initialize() error { func NewUpdater(document []byte) (*Updater, error) {
u := &Updater{Document: document}
u.updated = make(map[uint]struct{}) u.updated = make(map[uint]struct{})
// We only need to look for startxref roughly within // We only need to look for startxref roughly within
@@ -685,7 +686,7 @@ func (u *Updater) Initialize() error {
m := haystackRE.FindSubmatch(haystack) m := haystackRE.FindSubmatch(haystack)
if m == nil { if m == nil {
return errors.New("cannot find startxref") return nil, errors.New("cannot find startxref")
} }
xrefOffset, _ := strconv.ParseInt(string(m[1]), 10, 64) xrefOffset, _ := strconv.ParseInt(string(m[1]), 10, 64)
@@ -696,20 +697,20 @@ func (u *Updater) Initialize() error {
var throwawayStack []Object var throwawayStack []Object
for { for {
if _, ok := loadedXrefs[xrefOffset]; ok { if _, ok := loadedXrefs[xrefOffset]; ok {
return errors.New("circular xref offsets") return nil, errors.New("circular xref offsets")
} }
if xrefOffset >= int64(len(u.Document)) { if xrefOffset >= int64(len(u.Document)) {
return errors.New("invalid xref offset") return nil, errors.New("invalid xref offset")
} }
lex := Lexer{u.Document[xrefOffset:]} lex := Lexer{u.Document[xrefOffset:]}
if err := u.loadXref(&lex, loadedEntries); err != nil { if err := u.loadXref(&lex, loadedEntries); err != nil {
return err return nil, err
} }
trailer, _ := u.parse(&lex, &throwawayStack) trailer, _ := u.parse(&lex, &throwawayStack)
if trailer.Kind != Dict { if trailer.Kind != Dict {
return errors.New("invalid trailer dictionary") return nil, errors.New("invalid trailer dictionary")
} }
if len(loadedXrefs) == 0 { if len(loadedXrefs) == 0 {
u.Trailer = trailer.Dict u.Trailer = trailer.Dict
@@ -722,7 +723,7 @@ func (u *Updater) Initialize() error {
} }
// FIXME: We don't check for size_t over or underflow. // FIXME: We don't check for size_t over or underflow.
if !prevOffset.IsInteger() { if !prevOffset.IsInteger() {
return errors.New("invalid Prev offset") return nil, errors.New("invalid Prev offset")
} }
xrefOffset = int64(prevOffset.Number) xrefOffset = int64(prevOffset.Number)
} }
@@ -731,10 +732,10 @@ func (u *Updater) Initialize() error {
lastSize, ok := u.Trailer["Size"] lastSize, ok := u.Trailer["Size"]
if !ok || !lastSize.IsInteger() || lastSize.Number <= 0 { if !ok || !lastSize.IsInteger() || lastSize.Number <= 0 {
return errors.New("invalid or missing cross-reference table Size") return nil, errors.New("invalid or missing cross-reference table Size")
} }
u.xrefSize = uint(lastSize.Number) u.xrefSize = uint(lastSize.Number)
return nil return u, nil
} }
// Get retrieves an object by its number and generation--may return // Get retrieves an object by its number and generation--may return
@@ -1097,8 +1098,8 @@ func FillInSignature(document []byte, signOff, signLen int,
// PDF 1.6. // PDF 1.6.
func Sign(document []byte, func Sign(document []byte,
key crypto.PrivateKey, certs []*x509.Certificate) ([]byte, error) { key crypto.PrivateKey, certs []*x509.Certificate) ([]byte, error) {
pdf := &Updater{Document: document} pdf, err := NewUpdater(document)
if err := pdf.Initialize(); err != nil { if err != nil {
return nil, err return nil, err
} }