2022-11-12：以下rust语言代码中，结构体S实现了crate::T1::T2的方法，如何获取方法列表？以下代码应该返回[“m1”,“m2”,“m5”]，顺序不限。m3是S的方法，但并不属于crate::T1::T2的。m4也是S的方法，但这是实现T3的，也不属于crate::T1::T2的。
pub struct S;
impl crate::T1::T2 for S {
fn m1(&mut self){}
fn m2(&mut self){}
}
impl S {
fn m3(&mut self){}
}
impl T3 for S {
fn m4(&mut self){}
}
impl crate::T1::T2 for S {
fn m5(&mut self){}
}
答案2022-11-12：
要解析rust的代码，syn，quote，proc-macro2合理利用这三个库。
使用场景是写框架。
代码如下：
// main.rs文件内容如下：
use quote::quote;
use std::collections::HashSet;
use std::error::Error;
use syn::spanned::Spanned;
use syn::visit::Visit;
#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
let content = include_str!("test.rs.txt");
let ast: syn::File = syn::parse_file(content)?;
let mut a = ImplVisitor::new("crate::T1::T2", "S");
a.visit_file(&ast);
println!("out_method_name_set = {:#?}", a.out_method_name_set);
Ok(())
}
// 遍历服务的方法
pub struct ImplMethodVisitor {
// 收集方法
pub out_method_name_set: HashSet<String>,
}
impl ImplMethodVisitor {
pub fn new() -> Self {
Self {
out_method_name_set: HashSet::new(),
}
}
}
impl<'ast> Visit<'ast> for ImplMethodVisitor {
fn visit_impl_item_method(&mut self, node: &'ast syn::ImplItemMethod) {
// 获取方法名
let method_a = &node.sig.ident;
let method = format!("{}", quote! {#method_a});
// 将方法保存起来
self.out_method_name_set.insert(method);
// Delegate to the default impl to visit any nested functions.
//visit::visit_impl_item_method(self, node);
}
}
// 遍历服务的实现
pub struct ImplVisitor {
// 接口名
pub interface_name: String,
// 服务名
pub service_name: String,
// 收集方法
pub out_method_name_set: HashSet<String>,
// 结束行
pub out_end_line: usize,
// 结束列
pub out_end_column: usize,
}
impl ImplVisitor {
pub fn new(interface_name: &str, service_name: &str) -> Self {
Self {
interface_name: String::from(interface_name),
service_name: String::from(service_name),
out_method_name_set: HashSet::new(),
out_end_line: 0,
out_end_column: 0,
}
}
}
impl<'ast> Visit<'ast> for ImplVisitor {
fn visit_item_impl(&mut self, node: &'ast syn::ItemImpl) {
// 获取服务名称
let service_a = node.self_ty.as_ref();
let mut service = String::new();
match service_a {
syn::Type::Path(service_b) => {
let mut ans = String::new();
for service_c in service_b.path.segments.iter() {
let service_d = service_c.ident.clone();
ans.push_str("::");
let aaa = format!("{}", quote! {#service_d});
ans.push_str(&aaa);
}
//println!("找到Service----{}",&ans[2..]);
service = String::from(&ans[2..]);
}
_ => {
//println!("没找到Service");
}
}
// 获取接口名称
let interface_a = &node.trait_;
let mut interface = String::new();
match interface_a {
Some(interface_b) => {
let interface_c = &interface_b.1;
let mut ans = String::new();
for interface_d in interface_c.segments.iter() {
let interface_e = &interface_d.ident;
ans.push_str("::");
let interface_f = format!("{}", quote! {#interface_e});
ans.push_str(&interface_f);
}
//println!("找到接口----{}",&ans[2..]);
interface = String::from(&ans[2..]);
}
_ => {
//println!("没找到接口");
}
}
if self.interface_name != interface {
//println!("接口不匹配");
return;
}
if self.service_name != service {
//println!("服务名称不匹配");
return;
}
// println!("接口名和服务名都匹配----{}----{}",interface,service);
// 修改结束索引
self.out_end_line = node.span().end().line - 1;
self.out_end_column = node.span().end().column - 1;
// 遍历方法
let mut mv = ImplMethodVisitor::new();
mv.visit_item_impl(node);
// 将方法保存起来
for m in mv.out_method_name_set.iter() {
self.out_method_name_set.insert(String::from(m));
}
// Delegate to the default impl to visit any nested functions.
//visit::visit_item_impl(self, node);
}
}
// test.rs.txt内容如下：
pub struct S;
impl crate::T1::T2 for S {
fn m1(&mut self){}
fn m2(&mut self){}
}
impl S {
fn m3(&mut self){}
}
impl T3 for S {
fn m4(&mut self){}
}
impl crate::T1::T2 for S {
fn m5(&mut self){}
}
# Cargo.toml内容如下：
[package]
name = "rust-ast"
version = "0.1.0"
edition = "2021"
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[dependencies]
tokio = { version = "1.0", features = ["full"] }
anyhow = "1.0.66"
proc-macro2={ version = "1.0.47", features = ["span-locations"] }
syn = {version = "1.0",features=["full","extra-traits","visit"]}
quote = "1"
执行结果如下：
