Write out LazyObjectStreamObject without temporary decoding.

fancycode · hhrutter · commit 91619f051f07 · 2024-04-24T11:39:26.000+02:00
diff --git a/pkg/pdfcpu/model/dereference.go b/pkg/pdfcpu/model/dereference.go
@@ -61,7 +61,7 @@ func ProcessRefCounts(xRefTable *XRefTable, o types.Object) {
 	}
 }
 
-func (xRefTable *XRefTable) indRefToObject(ir *types.IndirectRef) (types.Object, error) {
+func (xRefTable *XRefTable) indRefToObject(ir *types.IndirectRef, decodeLazy bool) (types.Object, error) {
 	if ir == nil {
 		return nil, errors.New("pdfcpu: indRefToObject: input argument is nil")
 	}
@@ -76,7 +76,7 @@ func (xRefTable *XRefTable) indRefToObject(ir *types.IndirectRef) (types.Object,
 
 	xRefTable.CurObj = int(ir.ObjectNumber)
 
-	if l, ok := entry.Object.(*types.LazyObjectStreamObject); ok {
+	if l, ok := entry.Object.(*types.LazyObjectStreamObject); ok && decodeLazy {
 		ob, err := l.DecodedObject(context.TODO())
 		if err != nil {
 			return nil, err
@@ -98,7 +98,17 @@ func (xRefTable *XRefTable) Dereference(o types.Object) (types.Object, error) {
 		return o, nil
 	}
 
-	return xRefTable.indRefToObject(&ir)
+	return xRefTable.indRefToObject(&ir, true)
+}
+
+func (xRefTable *XRefTable) DereferenceForWrite(o types.Object) (types.Object, error) {
+	ir, ok := o.(types.IndirectRef)
+	if !ok {
+		// Nothing do dereference.
+		return o, nil
+	}
+
+	return xRefTable.indRefToObject(&ir, false)
 }
 
 // DereferenceBoolean resolves and validates a boolean object, which may be an indirect reference.
diff --git a/pkg/pdfcpu/model/xreftable.go b/pkg/pdfcpu/model/xreftable.go
@@ -982,7 +982,7 @@ func (xRefTable *XRefTable) Catalog() (types.Dict, error) {
 		return nil, errors.New("pdfcpu: Catalog: missing root dict")
 	}
 
-	o, err := xRefTable.indRefToObject(xRefTable.Root)
+	o, err := xRefTable.indRefToObject(xRefTable.Root, true)
 	if err != nil || o == nil {
 		return nil, err
 	}
@@ -999,7 +999,7 @@ func (xRefTable *XRefTable) Catalog() (types.Dict, error) {
 
 // EncryptDict returns a pointer to the root object / catalog.
 func (xRefTable *XRefTable) EncryptDict() (types.Dict, error) {
-	o, err := xRefTable.indRefToObject(xRefTable.Encrypt)
+	o, err := xRefTable.indRefToObject(xRefTable.Encrypt, true)
 	if err != nil || o == nil {
 		return nil, err
 	}
diff --git a/pkg/pdfcpu/writeObjects.go b/pkg/pdfcpu/writeObjects.go
@@ -673,6 +673,9 @@ func writeObjectGeneric(ctx *model.Context, o types.Object, objNr, genNr int) (e
 	case types.Name:
 		err = writeNameObject(ctx, objNr, genNr, o)
 
+	case *types.LazyObjectStreamObject:
+		err = writeObject(ctx, objNr, genNr, o.PDFString())
+
 	default:
 		err = errors.Errorf("writeIndirectObject: undefined PDF object #%d %T\n", objNr, o)
 	}
@@ -691,7 +694,7 @@ func writeIndirectObject(ctx *model.Context, ir types.IndirectRef) error {
 		return nil
 	}
 
-	o, err := ctx.Dereference(ir)
+	o, err := ctx.DereferenceForWrite(ir)
 	if err != nil {
 		return errors.Wrapf(err, "writeIndirectObject: unable to dereference indirect object #%d", objNr)
 	}

Original file line number	Diff line number	Diff line change
`@@ -982,7 +982,7 @@ func (xRefTable *XRefTable) Catalog() (types.Dict, error) {`
`982`	`982`	`return nil, errors.New("pdfcpu: Catalog: missing root dict")`
`983`	`983`	`}`
`984`	`984`
`985`		`- o, err := xRefTable.indRefToObject(xRefTable.Root)`
	`985`	`+ o, err := xRefTable.indRefToObject(xRefTable.Root, true)`
`986`	`986`	`if err != nil \|\| o == nil {`
`987`	`987`	`return nil, err`
`988`	`988`	`}`
`@@ -999,7 +999,7 @@ func (xRefTable *XRefTable) Catalog() (types.Dict, error) {`
`999`	`999`
`1000`	`1000`	`// EncryptDict returns a pointer to the root object / catalog.`
`1001`	`1001`	`func (xRefTable *XRefTable) EncryptDict() (types.Dict, error) {`
`1002`		`- o, err := xRefTable.indRefToObject(xRefTable.Encrypt)`
	`1002`	`+ o, err := xRefTable.indRefToObject(xRefTable.Encrypt, true)`
`1003`	`1003`	`if err != nil \|\| o == nil {`
`1004`	`1004`	`return nil, err`
`1005`	`1005`	`}`
Original file line number	Diff line number	Diff line change
`@@ -673,6 +673,9 @@ func writeObjectGeneric(ctx *model.Context, o types.Object, objNr, genNr int) (e`
`673`	`673`	`case types.Name:`
`674`	`674`	`err = writeNameObject(ctx, objNr, genNr, o)`
`675`	`675`
	`676`	`+ case *types.LazyObjectStreamObject:`
	`677`	`+ err = writeObject(ctx, objNr, genNr, o.PDFString())`
	`678`	`+`
`676`	`679`	`default:`
`677`	`680`	`err = errors.Errorf("writeIndirectObject: undefined PDF object #%d %T\n", objNr, o)`
`678`	`681`	`}`
`@@ -691,7 +694,7 @@ func writeIndirectObject(ctx *model.Context, ir types.IndirectRef) error {`
`691`	`694`	`return nil`
`692`	`695`	`}`
`693`	`696`
`694`		`- o, err := ctx.Dereference(ir)`
	`697`	`+ o, err := ctx.DereferenceForWrite(ir)`
`695`	`698`	`if err != nil {`
`696`	`699`	`return errors.Wrapf(err, "writeIndirectObject: unable to dereference indirect object #%d", objNr)`
`697`	`700`	`}`