Struct ProcessorContext

pub struct ProcessorContext {

    pub file_format: FileFormat,
    pub manufacturer: Option<String>,
    pub model: Option<String>,
    pub firmware: Option<String>,
    pub format_version: Option<String>,
    pub table_name: String,
    pub tag_id: Option<u16>,
    pub directory_path: Vec<String>,
    pub data_offset: usize,
    pub parent_tags: HashMap<String, TagValue>,
    pub parameters: HashMap<String, String>,
    pub byte_order: Option<ByteOrder>,
    pub base_offset: usize,
    pub data_size: Option<usize>,
}

Rich context passed to processors for capability assessment and processing

This structure provides all the information a processor needs to determine if it can handle the current data and to perform sophisticated processing. It mirrors ExifTool’s combination of $self (ExifTool object state) and $dirInfo (directory information).

ExifTool Reference

ExifTool processors receive context through multiple mechanisms:

• $self - ExifTool object with extracted tags and state
• $dirInfo - Directory information hash with processing parameters
• Global state like current file type, byte order, etc.

Fields

file_format: FileFormat

File format being processed Used for processor selection (e.g., JPEG vs TIFF vs RAW)

manufacturer: Option<String>

Camera manufacturer extracted from Make tag Primary factor in processor selection

model: Option<String>

Camera model extracted from Model tag Used for model-specific processor variants

firmware: Option<String>

Firmware version if available Some processors need firmware-specific handling

format_version: Option<String>

Format version for format-specific processing Used by processors that handle multiple format generations

table_name: String

Current table name being processed Helps processors understand their context (e.g., “Canon::AFInfo”)

tag_id: Option<u16>

Current tag ID being processed (if applicable) Used for tag-specific processor selection

directory_path: Vec<String>

IFD hierarchy path for nested processing Tracks the path through nested IFDs (e.g., [“IFD0”, “ExifIFD”, “MakerNotes”])

data_offset: usize

Current data offset in the file Important for offset-based processors and validation

parent_tags: HashMap<String, TagValue>

Previously extracted tags available as context Processors can use these for conditional logic and cross-references

parameters: HashMap<String, String>

Additional parameters from SubDirectory configuration ExifTool: SubDirectory parameters like DecryptStart, ByteOrder, etc.

byte_order: Option<ByteOrder>

Byte order for current data processing Some processors need explicit byte order information

base_offset: usize

Base offset for relative address calculations Critical for processors that handle offset-based data

data_size: Option<usize>

Size of data being processed (if known) Used for bounds checking and validation

Implementations

impl ProcessorContext

pub fn new(file_format: FileFormat, table_name: String) -> Self

Create a new processor context with minimal required information

pub fn with_camera_info( file_format: FileFormat, table_name: String, manufacturer: Option<String>, model: Option<String>, ) -> Self

Create context with manufacturer and model information

pub fn with_manufacturer(self, manufacturer: String) -> Self

Set manufacturer information

pub fn with_model(self, model: String) -> Self

Set model information

pub fn with_firmware(self, firmware: String) -> Self

Set firmware version

pub fn with_format_version(self, version: String) -> Self

Set format version

pub fn with_tag_id(self, tag_id: u16) -> Self

Set current tag ID

pub fn with_directory_path(self, path: Vec<String>) -> Self

Set directory path

pub fn with_data_offset(self, offset: usize) -> Self

Set data offset

pub fn with_parent_tags(self, tags: HashMap<String, TagValue>) -> Self

Set parent tags

pub fn add_parent_tag(&mut self, name: String, value: TagValue)

Add a parent tag

pub fn with_parent_tag(self, name: String, value: TagValue) -> Self

Add a parent tag (builder pattern)

pub fn with_parameters(self, parameters: HashMap<String, String>) -> Self

Set processing parameters

pub fn add_parameter(&mut self, key: String, value: String)

Add a processing parameter

pub fn with_byte_order(self, byte_order: ByteOrder) -> Self

Set byte order

pub fn with_base_offset(self, base_offset: usize) -> Self

Set base offset

pub fn with_data_size(self, size: usize) -> Self

Set data size

pub fn get_parameter(&self, key: &str) -> Option<&String>

Get a parameter value by key

pub fn get_parent_tag(&self, name: &str) -> Option<&TagValue>

Get a parent tag value by name

pub fn has_required_field(&self, field: &str) -> bool

Check if a required context field is available

pub fn validate_required_fields( &self, required_fields: &[String], ) -> Result<(), Vec<String>>

Validate that all required fields are present

pub fn derive_for_nested(&self, table_name: String, tag_id: Option<u16>) -> Self

Create a derived context for nested processing

This creates a new context based on the current one but updated for processing a nested structure (like a SubDirectory).

pub fn get_directory_path_string(&self) -> String

Get the current directory path as a string

pub fn is_manufacturer(&self, manufacturer: &str) -> bool

Check if this context represents a specific manufacturer

pub fn model_matches(&self, pattern: &str) -> bool

Check if the model matches a pattern

pub fn get_nikon_encryption_keys(&self) -> Option<(String, u32)>

Get encryption key information for Nikon processors

This is a specialized method for Nikon’s encrypted data processing that extracts the serial number and shutter count for decryption.

Trait Implementations

impl Clone for ProcessorContext

fn clone(&self) -> ProcessorContext

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ProcessorContext

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ProcessorContext

fn default() -> Self

Returns the “default value” for a type.