classfile_parser/
lib.rs

1//! A parser for [Java Classfiles](https://docs.oracle.com/javase/specs/jvms/se10/html/jvms-4.html)
2
3use std::fs::File;
4use std::io::{prelude::*, BufReader};
5use std::path::Path;
6
7#[macro_use]
8extern crate nom;
9
10#[macro_use]
11extern crate bitflags;
12
13pub mod attribute_info;
14pub mod constant_info;
15pub mod field_info;
16pub mod method_info;
17
18pub mod code_attribute;
19
20pub mod parser;
21pub mod types;
22
23pub use parser::class_parser;
24pub use types::*;
25
26/// Attempt to parse a class file given a path to a class file (without .class extension)
27///
28/// ```rust
29/// match classfile_parser::parse_class("./java-assets/compiled-classes/BasicClass") {
30///     Ok(class_file) => {
31///         println!("version {},{}", class_file.major_version, class_file.minor_version);
32///     }
33///     Err(ex) => panic!("Failed to parse: {}", ex),
34/// };
35/// ```
36pub fn parse_class(class_name: &str) -> Result<ClassFile, String> {
37    let class_file_name = &format!("{}.class", class_name);
38    let path = Path::new(class_file_name);
39    let display = path.display();
40
41    let file = match File::open(path) {
42        Err(why) => {
43            return Err(format!("Unable to open {}: {}", display, &why.to_string()));
44        }
45        Ok(file) => file,
46    };
47
48    let mut reader = BufReader::new(file);
49    parse_class_from_reader(&mut reader, display.to_string())
50}
51
52/// Attempt to parse a class file given a reader that implements the std::io::Read trait.
53/// The file_path parameter is only used in case of errors to provide reasonable error
54/// messages.
55///
56/// ```rust
57/// let mut reader = "this_will_be_parsed_as_classfile".as_bytes();
58/// let result = classfile_parser::parse_class_from_reader(&mut reader, "path/to/Java.class".to_string());
59/// assert!(result.is_err());
60/// ```
61pub fn parse_class_from_reader<T: Read>(
62    reader: &mut T,
63    file_path: String,
64) -> Result<ClassFile, String> {
65    let mut class_bytes = Vec::new();
66    if let Err(why) = reader.read_to_end(&mut class_bytes) {
67        return Err(format!(
68            "Unable to read {}: {}",
69            file_path,
70            &why.to_string()
71        ));
72    }
73
74    let parsed_class = class_parser(&class_bytes);
75    match parsed_class {
76        Ok((_, c)) => Ok(c),
77        _ => Err(format!("Failed to parse classfile {}", file_path)),
78    }
79}
classfile_parser/lib.rs

classfile_parser/
lib.rs
