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#![recursion_limit = "128"]
extern crate proc_macro;
extern crate proc_macro2;
#[macro_use]
extern crate syn;
#[macro_use]
extern crate quote;
extern crate regex;
use proc_macro2::*;
use std::collections::HashMap;
use regex::Captures;
use syn::DeriveInput;
use proc_macro::TokenStream;
#[proc_macro_derive(Request)]
pub fn request(input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeriveInput);
let ref name = input.ident;
let enum_ = match input.data {
syn::Data::Enum(ref enum_) => enum_,
_ => panic!("only enums are supported")
};
let request_clauses = enum_.variants.iter().map(|var| {
let var_name = &var.ident;
quote! {
#name::#var_name(ref mut a) => a.request(buf)
}
});
let from_instances = enum_.variants.iter().map(|var| {
let ty = &var.fields.iter().next().unwrap().ty;
let var_name = &var.ident;
quote! {
impl std::convert::From<#ty> for #name {
fn from(s: #ty) -> #name {
#name::#var_name(s)
}
}
impl std::convert::From<#name> for #ty {
fn from(s: #name) -> #ty {
match s {
#name::#var_name(s) => s,
_ => panic!(concat!("Wrong conversion into ", stringify!(#ty), " for type ", stringify!(#name)))
}
}
}
}
});
TokenStream::from(quote!{
impl pleingres::Request for #name {
fn request(&mut self, buf: &mut pleingres::Buffer) {
match *self {
#(#request_clauses),*
}
}
}
#(#from_instances)*
})
}
#[proc_macro_derive(HandleRowJoin)]
pub fn handle_row_join(input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeriveInput);
let ref name = input.ident;
let enum_ = match input.data {
syn::Data::Enum(ref enum_) => enum_,
_ => panic!("only enums are supported")
};
let row_clauses = enum_.variants.iter().map(|var| {
let var_name = &var.ident;
quote! {
#name::#var_name(ref mut a) => a.row(row)
}
});
let complete_clauses = enum_.variants.iter().map(|var| {
let var_name = &var.ident;
quote! {
#name::#var_name(ref mut a) => a.complete(n)
}
});
let ready_clauses = enum_.variants.iter().map(|var| {
let var_name = &var.ident;
quote! {
#name::#var_name(ref mut a) => a.ready_for_query()
}
});
let err_clauses = enum_.variants.iter().map(|var| {
let var_name = &var.ident;
quote! {
#name::#var_name(ref mut a) => a.err(err)
}
});
TokenStream::from(quote!{
impl pleingres::HandleRow for #name {
fn row(&mut self, row: pleingres::Row) -> bool {
match *self {
#(#row_clauses),*
}
}
fn complete(&mut self, n: u32) {
match *self {
#(#complete_clauses),*
}
}
fn ready_for_query(&mut self) {
match *self {
#(#ready_clauses),*
}
}
fn err(&mut self, err: &str) {
match *self {
#(#err_clauses),*
}
}
}
})
}
#[proc_macro_attribute]
pub fn sql(attr: proc_macro::TokenStream, item: proc_macro::TokenStream) -> proc_macro::TokenStream {
let attr = proc_macro2::TokenStream::from(attr);
let item = proc_macro2::TokenStream::from(item);
let re = regex::Regex::new(r"\$([a-zA-Z0-9_\.]+)").unwrap();
let binds = attr.into_iter().filter_map(|s| {
match s {
TokenTree::Literal(_) => {},
_ => return None,
}
let s = format!("{}", s);
let s = s.trim_matches('"');
let mut variable_numbers = HashMap::new();
let mut binds = Vec::new();
let replaced = re.replace_all(&s, |cap: &Captures| {
let var = cap.get(1).unwrap().as_str();
if variable_numbers.get(var).is_none() {
let len = format!("${}", variable_numbers.len() + 1);
variable_numbers.insert(var.to_string(), len);
let fields = var.split('.').map(|field| {
syn::Ident::new(&field, Span::call_site())
});
binds.push(quote!(
&self.#(#fields).*
));
}
variable_numbers.get(var).unwrap().to_string()
});
Some(quote! {
buf.bind(#replaced, &[#(#binds),*]).execute(0);
})
});
let mut name = None;
let mut item = item.into_iter();
let mut item_ = Vec::new();
loop {
match item.next() {
Some(TokenTree::Ident(id)) => {
if id.to_string() == "struct" {
let it = item.next().unwrap();
name = Some(syn::Ident::new(&format!("{}", it), it.span()));
item_.push(TokenTree::Ident(id));
item_.push(it);
} else {
item_.push(TokenTree::Ident(id));
}
}
None => break,
Some(it) => {
item_.push(it)
}
}
}
let name = name.unwrap();
use std::iter::FromIterator;
let item = proc_macro2::TokenStream::from_iter(item_);
let tokens = quote! {
impl pleingres::Request for #name {
fn request(&mut self, buf: &mut pleingres::Buffer) {
#(#binds)*
debug!("request sent");
}
}
#item
};
proc_macro::TokenStream::from(tokens)
}