Module schema 

Schema system for defining Total War file formats.

This module provides the infrastructure for defining and managing schemas that describe the binary structure of Total War game files, primarily database tables and localization files.

Overview

A Schema contains Definitions that specify the exact binary layout of different file types. Each table can have multiple definitions to support different versions across game patches. The schema system also supports runtime patches to override field properties without modifying the base schema.

Key Components

• Schema: The main container holding all table definitions and patches for a game
• Definition: Describes one version of a table’s structure (fields, types, constraints)
• Field: Represents a single column in a table with its type and metadata
• FieldType: The data type of a field (integers, strings, booleans, sequences, etc.)
• DefinitionPatch: Runtime modifications to field properties

Schema Versioning

• Each game has its own schema file (e.g., warhammer_3.ron)
• The schema format version (currently v5) is tracked separately from table versions
• Legacy schema formats (like v4) can be automatically upgraded via Schema::update()

Loading and Saving

Schemas are typically stored in RON format but can also be exported to JSON:

use rpfm_lib::schema::Schema;
use std::path::Path;

// Load a schema
let schema_path = Path::new("schemas/warhammer_3.ron");
let schema = Schema::load(schema_path, None)?;

// Access table definitions
if let Some(defs) = schema.definitions_by_table_name("units_tables") {
    for def in defs {
        println!("Version {}: {} fields", def.version(), def.fields().len());
    }
}

Patches

Patches allow modifying field properties at runtime without changing the schema:

use rpfm_lib::schema::Schema;
use std::path::Path;

let schema = Schema::load(Path::new("schema.ron"), Some(Path::new("patches.ron")))?;

// Check if a field has a patched value
if let Some(value) = schema.patch_value("units_tables", "key", "is_key") {
    println!("Patched is_key value: {}", value);
}

Schema Repository

Schemas are maintained in a separate Git repository and can be updated independently from RPFM itself. The repository URL and branch are defined as constants in this module.

Structs

Definition

Defines the structure of a specific version of a database table.

Field

Defines a single field within a table definition.

Schema

Represents a complete schema file containing table definitions for a Total War game.

Enums

FieldType

Supported data types for table fields.

Constants

MERGE_COLOUR_NO_NAME

Name for unnamed colour groups.

MERGE_COLOUR_POST

Suffix for merged colour field names.

SCHEMA_BRANCH

Name of the Git branch to use when fetching schemas.

SCHEMA_FOLDER

Name of the folder containing all the schemas.

SCHEMA_REMOTE

Name of the Git remote to use when fetching schemas.

SCHEMA_REPO

URL of the remote Git repository containing the schema files.

Type Aliases

DefinitionPatch

This type defines patches for specific table definitions, in a ColumnName -> [key -> value] format.