Field and Method descriptor parsing

with tests
This commit is contained in:
nora 2021-08-28 23:38:37 +02:00
parent a1620476d8
commit 54ca19a45a
2 changed files with 263 additions and 16 deletions

View file

@ -1,23 +1,144 @@
#![allow(dead_code)]
struct MethodSignature {
args: Vec<Type>,
return_t: Type,
#[cfg(test)]
mod test;
use std::borrow::Cow;
use std::str::FromStr;
#[derive(Debug)]
pub struct ParseErr(pub Cow<'static, str>);
impl ParseErr {
pub fn str(str: &'static str) -> Self {
Self(Cow::Borrowed(str))
}
pub fn string(str: String) -> Self {
Self(Cow::Owned(str))
}
}
/// A Java type, found in signatures
enum Type {
/// A field descriptor for the type of a field in a class
#[derive(Clone, Debug, Eq, PartialEq, Hash)]
pub struct FieldDescriptor(pub FieldType);
/// The type of a field or method parameter
#[derive(Clone, Debug, Eq, PartialEq, Hash)]
pub enum FieldType {
/// B
Byte,
/// C
Char,
/// D
Double,
/// F
Float,
/// I
Int,
/// J
Long,
/// L `ClassName` ;
Object(String),
/// S
Short,
/// Z
Boolean,
/// [
Array(Box<Self>),
}
/// A method descriptor for the type of a method in a class
#[derive(Clone, Debug, Eq, PartialEq, Hash)]
pub struct MethodDescriptor {
parameters: Vec<FieldType>,
return_: MethodType,
}
/// The type of a method
#[derive(Clone, Debug, Eq, PartialEq, Hash)]
pub enum MethodType {
Some(FieldType),
/// V
Void,
/// B
Boolean,
Byte,
Short,
Int,
Long,
Float,
Double,
Object,
/// [
Array(Box<Type>),
}
impl FromStr for FieldDescriptor {
type Err = ParseErr;
fn from_str(s: &str) -> Result<Self, Self::Err> {
Ok(Self(FieldType::from_char_iter(&mut s.chars())?))
}
}
impl FieldType {
/// Consumes as much chars as needed from the char iterator and tries to parse itself
pub fn from_char_iter<I>(chars: &mut I) -> Result<Self, ParseErr>
where
I: Iterator<Item = char>,
{
let first = chars.next().ok_or_else(|| ParseErr::str("Empty string"))?;
Ok(match first {
'B' => Self::Byte,
'C' => Self::Char,
'D' => Self::Double,
'F' => Self::Float,
'I' => Self::Int,
'J' => Self::Long,
'L' => Self::Object({
let mut name = String::with_capacity(32); // we can expect ClassNames to be at least this long
loop {
let char = chars
.next()
.ok_or_else(|| ParseErr::str("Expected ; before end of string"))?;
if char == ';' {
break;
};
name.push(char);
}
name
}),
'S' => Self::Short,
'Z' => Self::Boolean,
'[' => Self::Array(Box::new(Self::from_char_iter(chars)?)),
c => {
return Err(ParseErr::string(format!(
"Invalid char in field descriptor {}",
c
)))
}
})
}
}
impl FromStr for MethodDescriptor {
type Err = ParseErr;
fn from_str(s: &str) -> Result<Self, Self::Err> {
let mut chars = s.chars().peekable();
if chars.next().ok_or_else(|| ParseErr::str("Empty string"))? != '(' {
return Err(ParseErr::str("Needs to start with '('"));
}
let mut parameters = Vec::new();
loop {
if let Some(')') = chars.peek() {
let _ = chars.next(); // consume the )
break;
}
parameters.push(FieldType::from_char_iter(&mut chars)?);
}
let return_ = if let Some('V') = chars.peek() {
MethodType::Void
} else {
MethodType::Some(FieldType::from_char_iter(&mut chars)?)
};
Ok(Self {
parameters,
return_,
})
}
}

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@ -0,0 +1,126 @@
use super::*;
#[test]
fn field_descriptor() {
let descriptors = [
FieldDescriptor::from_str("B").unwrap(),
FieldDescriptor::from_str("C").unwrap(),
FieldDescriptor::from_str("D").unwrap(),
FieldDescriptor::from_str("F").unwrap(),
FieldDescriptor::from_str("I").unwrap(),
FieldDescriptor::from_str("J").unwrap(),
FieldDescriptor::from_str("S").unwrap(),
FieldDescriptor::from_str("Z").unwrap(),
FieldDescriptor::from_str("[B").unwrap(),
FieldDescriptor::from_str("[[Z").unwrap(),
FieldDescriptor::from_str("Ljava/lang/String;").unwrap(),
FieldDescriptor::from_str("[[[Ljava/lang/String;").unwrap(),
];
type FT = FieldType;
let expected_descriptors = [
FieldDescriptor(FT::Byte),
FieldDescriptor(FT::Char),
FieldDescriptor(FT::Double),
FieldDescriptor(FT::Float),
FieldDescriptor(FT::Int),
FieldDescriptor(FT::Long),
FieldDescriptor(FT::Short),
FieldDescriptor(FT::Boolean),
FieldDescriptor(FT::Array(Box::new(FT::Byte))),
FieldDescriptor(FT::Array(Box::new(FT::Array(Box::new(FT::Boolean))))),
FieldDescriptor(FT::Object("java/lang/String".to_string())),
FieldDescriptor(FT::Array(Box::new(FT::Array(Box::new(FT::Array(
Box::new(FT::Object("java/lang/String".to_string())),
)))))),
];
let invalid_descriptors = ["", "Q", "[]", "[", "Ljava/lang/String", "L", "[[[Ljava"];
descriptors
.iter()
.zip(expected_descriptors.iter())
.for_each(|(a, b)| assert_eq!(a, b));
invalid_descriptors
.iter()
.map(|d| FieldDescriptor::from_str(d))
.for_each(|rs| {
if rs.is_ok() {
panic!("Successfully parsed invalid result, {:?}", rs);
}
});
}
#[test]
fn method_descriptor() {
let descriptors = vec![
MethodDescriptor::from_str("()V").unwrap(),
MethodDescriptor::from_str("(B)V").unwrap(),
MethodDescriptor::from_str("([ZZ)Ljava/lang/Object;").unwrap(),
MethodDescriptor::from_str("(IDLjava/lang/Thread;)Ljava/lang/Object;").unwrap(),
MethodDescriptor::from_str("(BBBBBBBBBB)B").unwrap(),
MethodDescriptor::from_str("()Z").unwrap(),
];
type FT = FieldType;
let expected_descriptors = [
MethodDescriptor {
parameters: vec![],
return_: MethodType::Void,
},
MethodDescriptor {
parameters: vec![FT::Byte],
return_: MethodType::Void,
},
MethodDescriptor {
parameters: vec![FT::Array(Box::new(FT::Boolean)), FT::Boolean],
return_: MethodType::Some(FT::Object("java/lang/Object".to_string())),
},
MethodDescriptor {
parameters: vec![
FT::Int,
FT::Double,
FT::Object("java/lang/Thread".to_string()),
],
return_: MethodType::Some(FT::Object("java/lang/Object".to_string())),
},
MethodDescriptor {
parameters: vec![
FT::Byte,
FT::Byte,
FT::Byte,
FT::Byte,
FT::Byte,
FT::Byte,
FT::Byte,
FT::Byte,
FT::Byte,
FT::Byte,
],
return_: MethodType::Some(FT::Byte),
},
MethodDescriptor {
parameters: vec![],
return_: MethodType::Some(FT::Boolean),
},
];
let invalid_descriptors = ["()", "(V)V", ")V", "(;)Z", "(java/lang/StringZ)", "V"];
invalid_descriptors
.iter()
.map(|d| MethodDescriptor::from_str(d))
.for_each(|rs| {
if rs.is_ok() {
panic!("Successfully parsed invalid result, {:?}", rs);
}
});
descriptors
.iter()
.zip(expected_descriptors.iter())
.for_each(|(a, b)| assert_eq!(a, b));
}