Plume/plume-macro/src/lib.rs

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#![recursion_limit = "128"]
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#[macro_use]
extern crate quote;
use proc_macro::TokenStream;
use proc_macro2::TokenStream as TokenStream2;
use std::fs::{read_dir, File};
use std::io::Read;
use std::path::Path;
use std::str::FromStr;
#[proc_macro]
pub fn import_migrations(input: TokenStream) -> TokenStream {
assert!(input.is_empty());
let migration_dir = if cfg!(feature = "postgres") {
"migrations/postgres"
} else if cfg!(feature = "sqlite") {
"migrations/sqlite"
} else {
"migrations"
};
let path = Path::new(env!("CARGO_MANIFEST_DIR"))
.ancestors()
.find(|path| path.join(migration_dir).is_dir() || path.join(".git").exists())
.expect("migrations dir not found")
.join(migration_dir);
let mut files = read_dir(path)
.unwrap()
.map(|dir| dir.unwrap())
.filter(|dir| dir.file_type().unwrap().is_dir())
.map(|dir| dir.path())
.collect::<Vec<_>>();
files.sort_unstable();
let migrations = files
.into_iter()
.map(|path| {
let mut up = path.clone();
let mut down = path.clone();
up.push("up.sql");
down.push("down.sql");
let mut up_sql = String::new();
let mut down_sql = String::new();
File::open(up).unwrap().read_to_string(&mut up_sql).unwrap();
File::open(down)
.unwrap()
.read_to_string(&mut down_sql)
.unwrap();
let name = path
.file_name()
.unwrap()
.to_str()
.unwrap()
.chars()
.filter(char::is_ascii_digit)
.take(14)
.collect::<String>();
(name, up_sql, down_sql)
})
.collect::<Vec<_>>();
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let migrations_name = migrations.iter().map(|m| &m.0);
let migrations_up = migrations
.iter()
.map(|m| m.1.as_str())
.map(file_to_migration)
.collect::<Vec<_>>();
let migrations_down = migrations
.iter()
.map(|m| m.2.as_str())
.map(file_to_migration)
.collect::<Vec<_>>();
/*
enum Action {
Sql(&'static str),
Function(&'static Fn(&Connection, &Path) -> Result<()>)
}*/
quote!(
ImportedMigrations(
&[#(ComplexMigration{name: #migrations_name, up: #migrations_up, down: #migrations_down}),*]
)
).into()
}
fn file_to_migration(file: &str) -> TokenStream2 {
let mut sql = true;
let mut acc = String::new();
let mut actions = vec![];
for line in file.lines() {
if sql {
if let Some(acc_str) = line.strip_prefix("--#!") {
if !acc.trim().is_empty() {
actions.push(quote!(Action::Sql(#acc)));
}
sql = false;
acc = acc_str.to_string();
acc.push('\n');
} else if line.starts_with("--") {
continue;
} else {
acc.push_str(line);
acc.push('\n');
}
} else if let Some(acc_str) = line.strip_prefix("--#!") {
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acc.push_str(acc_str);
acc.push('\n');
} else if line.starts_with("--") {
continue;
} else {
let func: TokenStream2 = trampoline(TokenStream::from_str(&acc).unwrap().into());
actions.push(quote!(Action::Function(&#func)));
sql = true;
acc = line.to_string();
acc.push('\n');
}
}
if !acc.trim().is_empty() {
if sql {
actions.push(quote!(Action::Sql(#acc)));
} else {
let func: TokenStream2 = trampoline(TokenStream::from_str(&acc).unwrap().into());
actions.push(quote!(Action::Function(&#func)));
}
}
quote!(
&[#(#actions),*]
)
}
/// Build a trampoline to allow reference to closure from const context
fn trampoline(closure: TokenStream2) -> TokenStream2 {
quote! {
{
fn trampoline<'a, 'b>(conn: &'a Connection, path: &'b Path) -> Result<()> {
(#closure)(conn, path)
}
trampoline
}
}
}