Add extra level of comparisons to CompareFields
This commit is contained in:
Paul Hauner
parent
55ef75a44e
commit
e43d27f3e4
@ -1,3 +1,152 @@
|
||||
//! Provides field-by-field comparisons for structs and vecs.
|
||||
//!
|
||||
//! Returns comparisons as data, without making assumptions about the desired equality (e.g.,
|
||||
//! does not `panic!` on inequality).
|
||||
//!
|
||||
//! Note: `compare_fields_derive` requires `PartialEq` and `Debug` implementations.
|
||||
//!
|
||||
//! ## Example
|
||||
//!
|
||||
//! ```rust
|
||||
//! use compare_fields::{CompareFields, Comparison, FieldComparison};
|
||||
//! use compare_fields_derive::CompareFields;
|
||||
//!
|
||||
//! #[derive(PartialEq, Debug, CompareFields)]
|
||||
//! pub struct Bar {
|
||||
//! a: u64,
|
||||
//! b: u16,
|
||||
//! #[compare_fields(as_slice)]
|
||||
//! c: Vec<Foo>
|
||||
//! }
|
||||
//!
|
||||
//! #[derive(Clone, PartialEq, Debug, CompareFields)]
|
||||
//! pub struct Foo {
|
||||
//! d: String
|
||||
//! }
|
||||
//!
|
||||
//! let cat = Foo {d: "cat".to_string()};
|
||||
//! let dog = Foo {d: "dog".to_string()};
|
||||
//! let chicken = Foo {d: "chicken".to_string()};
|
||||
//!
|
||||
//! let mut bar_a = Bar {
|
||||
//! a: 42,
|
||||
//! b: 12,
|
||||
//! c: vec![ cat.clone(), dog.clone() ],
|
||||
//! };
|
||||
//!
|
||||
//! let mut bar_b = Bar {
|
||||
//! a: 42,
|
||||
//! b: 99,
|
||||
//! c: vec![ chicken.clone(), dog.clone()]
|
||||
//! };
|
||||
//!
|
||||
//! let cat_dog = Comparison::Child(FieldComparison {
|
||||
//! field_name: "d".to_string(),
|
||||
//! equal: false,
|
||||
//! a: "\"cat\"".to_string(),
|
||||
//! b: "\"dog\"".to_string(),
|
||||
//! });
|
||||
//! assert_eq!(cat.compare_fields(&dog), vec![cat_dog]);
|
||||
//!
|
||||
//! let bar_a_b = vec![
|
||||
//! Comparison::Child(FieldComparison {
|
||||
//! field_name: "a".to_string(),
|
||||
//! equal: true,
|
||||
//! a: "42".to_string(),
|
||||
//! b: "42".to_string(),
|
||||
//! }),
|
||||
//! Comparison::Child(FieldComparison {
|
||||
//! field_name: "b".to_string(),
|
||||
//! equal: false,
|
||||
//! a: "12".to_string(),
|
||||
//! b: "99".to_string(),
|
||||
//! }),
|
||||
//! Comparison::Parent{
|
||||
//! field_name: "c".to_string(),
|
||||
//! equal: false,
|
||||
//! children: vec![
|
||||
//! FieldComparison {
|
||||
//! field_name: "0".to_string(),
|
||||
//! equal: false,
|
||||
//! a: "Some(Foo { d: \"cat\" })".to_string(),
|
||||
//! b: "Some(Foo { d: \"chicken\" })".to_string(),
|
||||
//! },
|
||||
//! FieldComparison {
|
||||
//! field_name: "1".to_string(),
|
||||
//! equal: true,
|
||||
//! a: "Some(Foo { d: \"dog\" })".to_string(),
|
||||
//! b: "Some(Foo { d: \"dog\" })".to_string(),
|
||||
//! }
|
||||
//! ]
|
||||
//! }
|
||||
//! ];
|
||||
//! assert_eq!(bar_a.compare_fields(&bar_b), bar_a_b);
|
||||
//!
|
||||
//!
|
||||
//!
|
||||
//! // TODO:
|
||||
//! ```
|
||||
use std::fmt::Debug;
|
||||
|
||||
#[derive(Debug, PartialEq, Clone)]
|
||||
pub enum Comparison {
|
||||
Child(FieldComparison),
|
||||
Parent {
|
||||
field_name: String,
|
||||
equal: bool,
|
||||
children: Vec<FieldComparison>,
|
||||
},
|
||||
}
|
||||
|
||||
impl Comparison {
|
||||
pub fn child<T: Debug + PartialEq<T>>(field_name: String, a: &T, b: &T) -> Self {
|
||||
Comparison::Child(FieldComparison::new(field_name, a, b))
|
||||
}
|
||||
|
||||
pub fn parent(field_name: String, equal: bool, children: Vec<FieldComparison>) -> Self {
|
||||
Comparison::Parent {
|
||||
field_name,
|
||||
equal,
|
||||
children,
|
||||
}
|
||||
}
|
||||
|
||||
pub fn from_slice<T: Debug + PartialEq<T>>(field_name: String, a: &[T], b: &[T]) -> Self {
|
||||
let mut children = vec![];
|
||||
|
||||
for i in 0..std::cmp::max(a.len(), b.len()) {
|
||||
children.push(FieldComparison::new(
|
||||
format!("{:}", i),
|
||||
&a.get(i),
|
||||
&b.get(i),
|
||||
));
|
||||
}
|
||||
|
||||
Self::parent(field_name, a == b, children)
|
||||
}
|
||||
|
||||
pub fn retain_children<F>(&mut self, f: F)
|
||||
where
|
||||
F: FnMut(&FieldComparison) -> bool,
|
||||
{
|
||||
match self {
|
||||
Comparison::Child(_) => (),
|
||||
Comparison::Parent { children, .. } => children.retain(f),
|
||||
}
|
||||
}
|
||||
|
||||
pub fn equal(&self) -> bool {
|
||||
match self {
|
||||
Comparison::Child(fc) => fc.equal,
|
||||
Comparison::Parent { equal, .. } => *equal,
|
||||
}
|
||||
}
|
||||
|
||||
pub fn not_equal(&self) -> bool {
|
||||
!self.equal()
|
||||
}
|
||||
}
|
||||
|
||||
#[derive(Debug, PartialEq, Clone)]
|
||||
pub struct FieldComparison {
|
||||
pub field_name: String,
|
||||
@ -7,5 +156,24 @@ pub struct FieldComparison {
|
||||
}
|
||||
|
||||
pub trait CompareFields {
|
||||
fn compare_fields(&self, b: &Self) -> Vec<FieldComparison>;
|
||||
fn compare_fields(&self, b: &Self) -> Vec<Comparison>;
|
||||
}
|
||||
|
||||
impl FieldComparison {
|
||||
pub fn new<T: Debug + PartialEq<T>>(field_name: String, a: &T, b: &T) -> Self {
|
||||
Self {
|
||||
field_name,
|
||||
equal: a == b,
|
||||
a: format!("{:?}", a),
|
||||
b: format!("{:?}", b),
|
||||
}
|
||||
}
|
||||
|
||||
pub fn equal(&self) -> bool {
|
||||
self.equal
|
||||
}
|
||||
|
||||
pub fn not_equal(&self) -> bool {
|
||||
!self.equal()
|
||||
}
|
||||
}
|
||||
|
||||
@ -1,46 +0,0 @@
|
||||
use compare_fields::{CompareFields, FieldComparison};
|
||||
use compare_fields_derive::CompareFields;
|
||||
|
||||
#[derive(Clone, Debug, CompareFields)]
|
||||
pub struct Simple {
|
||||
a: u64,
|
||||
b: u16,
|
||||
c: Vec<u8>,
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn compare() {
|
||||
let foo = Simple {
|
||||
a: 42,
|
||||
b: 12,
|
||||
c: vec![1, 2],
|
||||
};
|
||||
|
||||
let mut bar = foo.clone();
|
||||
|
||||
let comparisons = foo.compare_fields(&bar);
|
||||
|
||||
assert!(!comparisons.iter().any(|c| c.equal == false));
|
||||
|
||||
assert_eq!(
|
||||
comparisons[0],
|
||||
FieldComparison {
|
||||
equal: true,
|
||||
field_name: "a".to_string(),
|
||||
a: "42".to_string(),
|
||||
b: "42".to_string(),
|
||||
}
|
||||
);
|
||||
|
||||
bar.a = 30;
|
||||
|
||||
assert_eq!(
|
||||
foo.compare_fields(&bar)[0],
|
||||
FieldComparison {
|
||||
equal: false,
|
||||
field_name: "a".to_string(),
|
||||
a: "42".to_string(),
|
||||
b: "30".to_string(),
|
||||
}
|
||||
);
|
||||
}
|
||||
@ -5,7 +5,16 @@ use proc_macro::TokenStream;
|
||||
use quote::quote;
|
||||
use syn::{parse_macro_input, DeriveInput};
|
||||
|
||||
#[proc_macro_derive(CompareFields)]
|
||||
fn is_slice(field: &syn::Field) -> bool {
|
||||
for attr in &field.attrs {
|
||||
if attr.tts.to_string() == "( as_slice )" {
|
||||
return true;
|
||||
}
|
||||
}
|
||||
false
|
||||
}
|
||||
|
||||
#[proc_macro_derive(CompareFields, attributes(compare_fields))]
|
||||
pub fn compare_fields_derive(input: TokenStream) -> TokenStream {
|
||||
let item = parse_macro_input!(input as DeriveInput);
|
||||
|
||||
@ -17,37 +26,47 @@ pub fn compare_fields_derive(input: TokenStream) -> TokenStream {
|
||||
_ => panic!("compare_fields_derive only supports structs."),
|
||||
};
|
||||
|
||||
let mut idents_a = vec![];
|
||||
let mut field_names = vec![];
|
||||
let mut quotes = vec![];
|
||||
|
||||
for field in struct_data.fields.iter() {
|
||||
let ident = match &field.ident {
|
||||
let ident_a = match &field.ident {
|
||||
Some(ref ident) => ident,
|
||||
_ => panic!("compare_fields_derive only supports named struct fields."),
|
||||
};
|
||||
|
||||
field_names.push(format!("{:}", ident));
|
||||
idents_a.push(ident);
|
||||
}
|
||||
let field_name = format!("{:}", ident_a);
|
||||
let ident_b = ident_a.clone();
|
||||
|
||||
let idents_b = idents_a.clone();
|
||||
let idents_c = idents_a.clone();
|
||||
let idents_d = idents_a.clone();
|
||||
let quote = if is_slice(field) {
|
||||
quote! {
|
||||
comparisons.push(compare_fields::Comparison::from_slice(
|
||||
#field_name.to_string(),
|
||||
&self.#ident_a,
|
||||
&b.#ident_b)
|
||||
);
|
||||
}
|
||||
} else {
|
||||
quote! {
|
||||
comparisons.push(
|
||||
compare_fields::Comparison::child(
|
||||
#field_name.to_string(),
|
||||
&self.#ident_a,
|
||||
&b.#ident_b
|
||||
)
|
||||
);
|
||||
}
|
||||
};
|
||||
|
||||
quotes.push(quote);
|
||||
}
|
||||
|
||||
let output = quote! {
|
||||
impl #impl_generics compare_fields::CompareFields for #name #ty_generics #where_clause {
|
||||
fn compare_fields(&self, b: &Self) -> Vec<compare_fields::FieldComparison> {
|
||||
fn compare_fields(&self, b: &Self) -> Vec<compare_fields::Comparison> {
|
||||
let mut comparisons = vec![];
|
||||
|
||||
#(
|
||||
comparisons.push(
|
||||
compare_fields::FieldComparison {
|
||||
equal: self.#idents_a == b.#idents_b,
|
||||
field_name: #field_names.to_string(),
|
||||
a: format!("{:?}", self.#idents_c),
|
||||
b: format!("{:?}", b.#idents_d),
|
||||
}
|
||||
);
|
||||
#quotes
|
||||
)*
|
||||
|
||||
comparisons
|
||||
|
||||
Loading…
Reference in New Issue
Block a user