Module view 

Class File View Module

The view module provides a low-level, structured view of a JVM Class file. Unlike the JvmProgram IR which is designed for manipulation and conversion, ClassInfo is a read-only representation that closely mirrors the physical structure of the .class file.

Why use Class View?

• Metadata Extraction: Quickly access class names, superclasses, and interfaces without parsing the entire method bytecode.
• Constant Pool Access: Directly inspect constant pool entries by their original indices.
• Performance: More efficient than full IR parsing when you only need high-level metadata.
• Verification: Useful for tools that need to verify the exact binary structure of a class file.

Core Structure: ClassInfo

ClassInfo contains:

• Version: Major and minor version numbers.
• Constant Pool: A raw list of constant pool entries.
• Access Flags: Class-level access modifiers.
• Class Names: Indices and resolved names for this class and its superclass.
• Interfaces: List of implemented interfaces.
• Fields & Methods: High-level metadata for members (without full instruction parsing).

Usage Example

use jvm_assembler::formats::class::ClassReadConfig;
use jvm_assembler::formats::class::reader::ClassReader;
use std::fs::File;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let file = File::open("MyClass.class")?;
    let config = ClassReadConfig::default();
    let reader = ClassReader::new(file, &config);

    // Get the low-level view instead of the full program
    let info = reader.get_info()?;

    println!("Class Name: {}", info.this_class_name);
    println!("Super Class: {}", info.super_class_name.as_deref().unwrap_or("None"));
    println!("Version: {}.{}", info.major_version, info.minor_version);

    Ok(())
}

Structs

ClassInfo

Information about a JVM class file