Work on forms - definitions

pdf/forms.go

@@ -19,7 +19,7 @@ import (
 )
 
 type PdfAcroForm struct {
-	Fields          []*PdfField
+	Fields          *[]*PdfField
 	NeedAppearances PdfObject
 	SigFlags        PdfObject
 	CO              PdfObject
@@ -29,24 +29,149 @@ type PdfAcroForm struct {
 	XFA             PdfObject
 }
 
-type PdfWidgetAnnotation {
-	Subtype PdfObject
-	H PdfObject
-	MK PdfObject
-	A PdfObject
-	AA PdfObject
-	BS PdfObject
-	Parent *PdfIndirectObject // Max 1 parent; Gets tricky for both form and annotation refs?  Seems to usually refer to the page one.
+func (r *PdfReader) newPdfAcroFormFromDict(d PdfObjectDictionary) (*PdfAcroForm, error) {
+	acroForm := PdfAcroForm{}
+
+	if obj, has := d["Fields"]; has {
+		obj, err := r.traceToObject(obj)
+		if err != nil {
+			return nil, err
+		}
+		fieldArray, ok := TraceToDirectObject(obj).(*PdfObjectArray)
+		if !ok {
+			return nil, fmt.Errorf("Fields not an array (%T)", obj)
+		}
+
+		fields := []*PdfField{}
+		for _, obj := range fieldArray {
+			obj, err := r.traceToObject(obj)
+			if err != nil {
+				return nil, err
+			}
+			fDict, ok := TraceToDirectObject(obj).(*PdfObjectDictionary)
+			if !ok {
+				return nil, fmt.Errorf("Invalid Fields entry: %T", obj)
+			}
+			field := newPdfFieldFromDict(fDict)
+			fields = append(fields, field)
+		}
+		acroForm.Fields = &fields
+	}
+
+	if obj, has := d["NeedAppearances"]; has {
+		acroForm.NeedAppearances = obj
+	}
+	if obj, has := d["SigFlags"]; has {
+		acroForm.SigFlags = obj
+	}
+	if obj, has := d["CO"]; has {
+		acroForm.CO = obj
+	}
+	if obj, has := d["DR"]; has {
+		acroForm.DR = obj
+	}
+	if obj, has := d["DA"]; has {
+		acroForm.DA = obj
+	}
+	if obj, has := d["Q"]; has {
+		acroForm.Q = obj
+	}
+	if obj, has := d["XFA"]; has {
+		acroForm.XFA = obj
+	}
+
+	return &acroForm, nil
+}
+
+func (this *PdfAcroForm) ToPdfObject() PdfObject {
+
+}
+
+func (r *PdfReader) newPdfFieldDict(d PdfObjectDictionary) (*PdfField, error) {
+	field := PdfField{}
+
+	// Field type (required in terminal fields).
+	// Can be /Btn /Tx /Ch /Sig
+	// Required for a terminal field (inheritable).
+	if obj, has := d["FT"]; has {
+		obj, err = r.traceToObject(obj)
+		if err != nil {
+			return nil, err
+		}
+		name, ok := obj.(*PdfObjectName)
+		if !ok {
+			return nil, fmt.Errorf("Invalid type of FT field (%T)", obj)
+		}
+
+		acroForm.FT = name
+	}
+
+	// In a non-terminal field, the Kids array shall refer to field dictionaries that are immediate descendants of this field.
+	// In a terminal field, the Kids array ordinarily shall refer to one or more separate widget annotations that are associated
+	// with this field. However, if there is only one associated widget annotation, and its contents have been merged into the field
+	// dictionary, Kids shall be omitted.
+
+	// Terminal field if:
+	// 1. Kids pointing to widget annotations (Kids[0].(*PdfField) casting fails)
+	// 2. Kids empty or missing and a the dict has a Subtype equivalent to "Widget"
+
+	if obj, has := d["Parent"]; has {
+		field.Parent = obj
+	}
+	if obj, has := d["Kids"]; has {
+		field.Kids = obj
+	}
+
+	// Partial field name (Optional)
+	if obj, has := d["T"]; has {
+		field.T = obj
+	}
+	// Alternate description (Optional)
+	if obj, has := d["TU"]; has {
+		field.TU = obj
+	}
+	// Mapping name (Optional)
+	if obj, has := d["TM"]; has {
+		field.TM = obj
+	}
+	// Field flag. (Optional; inheritable)
+	if obj, has := d["Ff"]; has {
+		field.Ff = obj
+	}
+	// Value (Optional; inheritable) - Various types depending on the field type.
+	if obj, has := d["V"]; has {
+		field.V = obj
+	}
+	// Default value for reset (Optional; inheritable)
+	if obj, has := d["DV"]; has {
+		field.DV = obj
+	}
+	// Additional actions dictionary (Optional)
+	if obj, has := d["AA"]; has {
+		field.AA = obj
+	}
+
+	return &field, nil
+}
+
+type PdfAnnotationWidget struct {
+	Subtype PdfObject // Widget (required)
+	H       PdfObject
+	MK      PdfObject
+	A       PdfObject
+	AA      PdfObject
+	BS      PdfObject
+	Parent  *PdfIndirectObject // Max 1 parent; Gets tricky for both form and annotation refs?  Seems to usually refer to the page one.
 }
 
 type PdfField struct {
+	FT     *PdfObjectName // field type
 	Parent *PdfField
 	// In a non-terminal field, the Kids array shall refer to field dictionaries that are immediate descendants of this field.
 	// In a terminal field, the Kids array ordinarily shall refer to one or more separate widget annotations that are associated
 	// with this field. However, if there is only one associated widget annotation, and its contents have been merged into the field
 	// dictionary, Kids shall be omitted.
-	Kids []*PdfField
-	FT   *PdfObjectString // field type
+	Kids PdfObject
 	T    PdfObject
 	TU   PdfObject
 	TM   PdfObject
@@ -55,47 +180,38 @@ type PdfField struct {
 	DV   PdfObject
 	AA   PdfObject
 	// Widget annotation can be merged in.
+	// PdfAnnotationWidget
+}
 
-	// Variable text fields.
+func (this *PdfField) ToPdfObject() {
+	// If Kids refer only to a single pdf widget annotation widget, then can merge it in.
+}
+
+type PdfFieldVariableText struct {
+	PdfField
 	DA PdfObject
 	Q  PdfObject
 	DS PdfObject
 	RV PdfObject
+}
+
+type PdfFieldText struct {
+	PdfField
 	// Text field
 	MaxLen PdfObject // inheritable
+}
+
+type PdfFieldChoice struct {
+	PdfField
 	// Choice fields.
 	Opt PdfObject
 	TI  PdfObject
 	I   PdfObject
+}
+
+type PdfFieldSignature struct {
+	PdfField
 	// Signature fields (Table 232).
 	Lock PdfObject
 	SV   PdfObject
-	// Signature field lock dict (Table 233).
-	Type   PdfObject // SigFieldLock
-	Action *PdfObjectName
-	Fields PdfObject
-	// Signature field seed value dictionary (Table 234)
-	//Type //SV
-	Ff
-	Filter
-	SubFilter
-	DigestMethod
-	V
-	Cert
-	Reasons
-	MDP
-	TimeStamp
-	LegalAttestation
-	AddRevInfo
-	// Certificate seed value dictionary (Table 235).
-	// Type //SVCert
-	// Ff
-	Subject
-	SubjectDN
-	KeyUsage
-	Issuer
-	OID
-	URL
-	URLType
-	// S
 }

pdf/reader.go

@@ -393,6 +393,40 @@ func (this *PdfReader) GetForms() (*PdfObjectDictionary, error) {
 	return formsDict, nil
 }
 
+// XXX: Under construction.
+func (this *PdfReader) LoadForms() error {
+	if this.parser.crypter != nil && !this.parser.crypter.authenticated {
+		return nil, fmt.Errorf("File need to be decrypted first")
+	}
+
+	// Has forms?
+	catalog := this.catalog
+	obj, has := (*catalog)["AcroForm"]
+	if !has {
+		// Nothing to load.
+		return nil
+	}
+	var err error
+	obj, err = this.traceToObject(obj)
+	if err != nil {
+		return err
+	}
+	formsDict, ok := TraceToDirectObject(obj).(*PdfObjectDictionary)
+	if !ok {
+		common.Log.Debug("Invalid AcroForm entry %T", obj)
+		common.Log.Debug("Does not have forms")
+		return nil
+	}
+	common.Log.Debug("Has Acro forms")
+	// Load it.
+
+}
+
+// Recursive build form field tree.
+func (this *PdfReader) buildFieldTree(obj PdfObject) (*PdfOutlineTreeNode, error) {
+	// Describe how to do this first by hand.
+}
+
 func (this *PdfReader) lookupPageByObject(obj PdfObject) (*PdfPage, error) {
 	// can be indirect, direct, or reference
 	// look up the corresponding page