configuration.go

/*
Copyright 2018 The pdfcpu Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

	http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package pdfcpu

const (

	// ValidationStrict ensures 100% compliance with the spec (PDF 32000-1:2008).
	ValidationStrict = 0

	// ValidationRelaxed ensures PDF compliance based on frequently encountered validation errors.
	ValidationRelaxed = 1

	// StatsFileNameDefault is the standard stats filename.
	StatsFileNameDefault = "stats.csv"

	// PermissionsAll enables all user access permission bits.
	PermissionsAll int16 = -1 // 0xFFFF

	// PermissionsNone disables all user access permissions bits.
	PermissionsNone int16 = -3901 // 0xF0C3

)

// CommandMode specifies the operation being executed.
type CommandMode int

// The available commands.
const (
	VALIDATE CommandMode = iota
	OPTIMIZE
	SPLIT
	MERGE
	EXTRACTIMAGES
	EXTRACTFONTS
	EXTRACTPAGES
	EXTRACTCONTENT
	EXTRACTMETADATA
	TRIM
	ADDATTACHMENTS
	REMOVEATTACHMENTS
	EXTRACTATTACHMENTS
	LISTATTACHMENTS
	ADDPERMISSIONS
	LISTPERMISSIONS
	ENCRYPT
	DECRYPT
	CHANGEUPW
	CHANGEOPW
	STAMP
	ADDWATERMARKS
	IMPORTIMAGES
	ROTATE
	NUP
)

// Configuration of a Context.
type Configuration struct {

	// Enables PDF V1.5 compatible processing of object streams, xref streams, hybrid PDF files.
	Reader15 bool

	// Enables decoding of all streams (fontfiles, images..) for logging purposes.
	DecodeAllStreams bool

	// Validate against ISO-32000: strict or relaxed
	ValidationMode int

	// End of line char sequence for writing.
	Eol string

	// Turns on object stream generation.
	// A signal for compressing any new non-stream-object into an object stream.
	// true enforces WriteXRefStream to true.
	// false does not prevent xRefStream generation.
	WriteObjectStream bool

	// Switches between xRefSection (<=V1.4) and objectStream/xRefStream (>=V1.5) writing.
	WriteXRefStream bool

	// Turns on stats collection.
	// TODO Decision - unused.
	CollectStats bool

	// A CSV-filename holding the statistics.
	StatsFileName string

	// Supplied user password
	UserPW    string
	UserPWNew *string

	// Supplied owner password
	OwnerPW    string
	OwnerPWNew *string

	// EncryptUsingAES ensures AES encryption.
	// true: AES encryption
	// false: RC4 encryption.
	EncryptUsingAES bool

	// EncryptUsing128BitKey ensures 128 bit key length.
	// true: use 128 bit key
	// false: use 40 bit key
	EncryptUsing128BitKey bool

	// Supplied user access permissions, see Table 22
	UserAccessPermissions int16

	// Command being executed.
	Mode CommandMode
}

// NewDefaultConfiguration returns the default pdfcpu configuration.
func NewDefaultConfiguration() *Configuration {

	return &Configuration{
		Reader15:              true,
		DecodeAllStreams:      false,
		ValidationMode:        ValidationRelaxed,
		Eol:                   EolLF,
		WriteObjectStream:     true,
		WriteXRefStream:       true,
		CollectStats:          true,
		EncryptUsingAES:       true,
		EncryptUsing128BitKey: true,
		UserAccessPermissions: PermissionsNone,
	}
}

// ValidationModeString returns a string rep for the validation mode in effect.
func (c *Configuration) ValidationModeString() string {

	if c.ValidationMode == ValidationStrict {
		return "strict"
	}

	if c.ValidationMode == ValidationRelaxed {
		return "relaxed"
	}

	return ""
}