Tryanks/pdfsign
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Refactor object handling

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This commit is contained in:
Paul van Brouwershaven
2024-12-11 16:24:26 +01:00
parent 21dd78d75e
commit e5cdb61bea
11 changed files with 311 additions and 327 deletions
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40
sign/pdfcatalog.go
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@@ -1,16 +1,16 @@
package sign
import (
"bytes"
"strconv"
"strings"
)
func (context *SignContext) createCatalog() (string, error) {
var catalogBuilder strings.Builder
func (context *SignContext) createCatalog() ([]byte, error) {
var catalog_buffer bytes.Buffer
// Start the catalog object
catalogBuilder.WriteString(strconv.Itoa(int(context.CatalogData.ObjectId)) + " 0 obj\n")
catalogBuilder.WriteString("<< /Type /Catalog")
catalog_buffer.WriteString("<<\n")
catalog_buffer.WriteString(" /Type /Catalog")
// (Optional; PDF 1.4) The version of the PDF specification to which
// the document conforms (for example, 1.4) if later than the version
@@ -25,7 +25,7 @@ func (context *SignContext) createCatalog() (string, error) {
//
// If an incremental upgrade requires a version that is higher than specified by the document.
// if context.PDFReader.PDFVersion < "2.0" {
// catalogBuilder.WriteString(" /Version /2.0")
// catalog_buffer.WriteString(" /Version /2.0")
// }
// Retrieve the root and check for necessary keys in one loop
@@ -49,33 +49,33 @@ func (context *SignContext) createCatalog() (string, error) {
// Add Pages and Names references if they exist
if foundPages {
pages := root.Key("Pages").GetPtr()
catalogBuilder.WriteString(" /Pages " + strconv.Itoa(int(pages.GetID())) + " " + strconv.Itoa(int(pages.GetGen())) + " R")
catalog_buffer.WriteString(" /Pages " + strconv.Itoa(int(pages.GetID())) + " " + strconv.Itoa(int(pages.GetGen())) + " R")
}
if foundNames {
names := root.Key("Names").GetPtr()
catalogBuilder.WriteString(" /Names " + strconv.Itoa(int(names.GetID())) + " " + strconv.Itoa(int(names.GetGen())) + " R")
catalog_buffer.WriteString(" /Names " + strconv.Itoa(int(names.GetID())) + " " + strconv.Itoa(int(names.GetGen())) + " R")
}
// Start the AcroForm dictionary with /NeedAppearances
catalogBuilder.WriteString(" /AcroForm << /Fields [")
catalog_buffer.WriteString(" /AcroForm << /Fields [")
// Add existing signatures to the AcroForm dictionary
for i, sig := range context.SignData.ExistingSignatures {
if i > 0 {
catalogBuilder.WriteString(" ")
catalog_buffer.WriteString(" ")
}
catalogBuilder.WriteString(strconv.Itoa(int(sig.ObjectId)) + " 0 R")
catalog_buffer.WriteString(strconv.Itoa(int(sig.ObjectId)) + " 0 R")
}
// Add the visual signature field to the AcroForm dictionary
if len(context.SignData.ExistingSignatures) > 0 {
catalogBuilder.WriteString(" ")
catalog_buffer.WriteString(" ")
}
catalogBuilder.WriteString(strconv.Itoa(int(context.VisualSignData.ObjectId)) + " 0 R")
catalog_buffer.WriteString(strconv.Itoa(int(context.VisualSignData.ObjectId)) + " 0 R")
catalogBuilder.WriteString("]") // close Fields array
catalog_buffer.WriteString("]") // close Fields array
catalogBuilder.WriteString(" /NeedAppearances false")
catalog_buffer.WriteString(" /NeedAppearances false")
// Signature flags (Table 225)
//
@@ -100,14 +100,14 @@ func (context *SignContext) createCatalog() (string, error) {
// Set SigFlags and Permissions based on Signature Type
switch context.SignData.Signature.CertType {
case CertificationSignature, ApprovalSignature, TimeStampSignature:
catalogBuilder.WriteString(" /SigFlags 3")
catalog_buffer.WriteString(" /SigFlags 3")
case UsageRightsSignature:
catalogBuilder.WriteString(" /SigFlags 1")
catalog_buffer.WriteString(" /SigFlags 1")
}
// Finalize the AcroForm and Catalog object
catalogBuilder.WriteString(" >>") // Close AcroForm
catalogBuilder.WriteString(" >>\nendobj\n") // Close catalog object
catalog_buffer.WriteString(" >>\n") // Close AcroForm
catalog_buffer.WriteString(">>\n") // Close Catalog
return catalogBuilder.String(), nil
return catalog_buffer.Bytes(), nil
}