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#![deny(missing_docs, clippy::missing_docs_in_private_items)]
#![cfg_attr(windows, doc = include_str!("..\\README.md"))]
#![cfg_attr(not(windows), doc = include_str!("../README.md"))]
use std::env::{self, VarError};
use proc_macro::{Literal, TokenStream, TokenTree};
use proc_macro_error::{abort_call_site, proc_macro_error};
use quote::quote;
mod decrypt;
mod encrypt;
use decrypt::{decrypt, decrypt_none, decrypt_some};
use encrypt::{encrypt, EncryptedVariable};
macro_rules! syntax_error {
($macro_name:ident) => {
match $macro_name {
"envc" => abort_call_site!("Invalid syntax. Valid forms are `envc!(\"VAR_NAME\")` and `envc!(\"VAR_NAME\", \"custom error message\")`."),
"option_envc" => abort_call_site!("Invalid syntax. Expected input of the form `option_envc!(\"VAR_NAME\")`"),
_ => panic!("Unknown macro name")
}
};
}
#[doc(hidden)]
#[proc_macro_error]
#[proc_macro]
pub fn envc(tokens: TokenStream) -> TokenStream {
let (env_var_key, abort_message) = match parse(tokens, "envc") {
Input::VariableName(variable_name) => (
variable_name.clone(),
format!("environment variable `{}` not defined", &variable_name),
),
Input::VariableNameAndAbortMessage {
variable_name,
abort_message,
} => (variable_name, abort_message),
};
match env::var(&env_var_key) {
Ok(unencrypted_variable) => {
let EncryptedVariable { key, value, nonce } = encrypt(unencrypted_variable);
decrypt!(key, value, nonce)
}
Err(VarError::NotUnicode(_)) => {
abort_call_site!(
"Environment variable ${} contains non-unicode value",
&env_var_key
)
}
Err(VarError::NotPresent) => abort_call_site!("{}", abort_message),
}
.into()
}
#[doc(hidden)]
#[proc_macro_error]
#[proc_macro]
pub fn option_envc(tokens: TokenStream) -> TokenStream {
let env_var_key = match parse(tokens, "option_envc") {
Input::VariableName(variable_name) => variable_name,
Input::VariableNameAndAbortMessage { .. } => abort_call_site!(
"Invalid syntax. Expected input of the form `option_envc!(\"VAR_NAME\")`"
),
};
match env::var(&env_var_key) {
Ok(unencrypted_variable) => {
let EncryptedVariable { key, value, nonce } = encrypt(unencrypted_variable);
decrypt_some!(key, value, nonce)
}
Err(VarError::NotUnicode(_)) => {
abort_call_site!(
"Environment variable ${} contains non-unicode value",
&env_var_key
)
}
Err(VarError::NotPresent) => decrypt_none!(),
}
.into()
}
fn stringify(literal: &Literal) -> Option<String> {
let stringified = literal.to_string();
if stringified.starts_with('"') && stringified.ends_with('"') {
Some(stringified[1..stringified.len() - 1].to_owned())
} else {
None
}
}
enum Input {
VariableName(String),
VariableNameAndAbortMessage {
variable_name: String,
abort_message: String,
},
}
fn parse(tokens: TokenStream, macro_name: &str) -> Input {
let tokens_vec = tokens.into_iter().collect::<Vec<_>>();
match *tokens_vec.as_slice() {
[TokenTree::Literal(ref variable_literal)] => {
if let Some(variable) = stringify(variable_literal) {
Input::VariableName(variable)
} else {
syntax_error!(macro_name)
}
}
[TokenTree::Literal(ref variable_literal), TokenTree::Punct(ref comma), TokenTree::Literal(ref message_literal)] => {
match (
stringify(variable_literal),
comma.as_char(),
stringify(message_literal),
) {
(Some(variable_name), ',', Some(abort_message)) => {
Input::VariableNameAndAbortMessage {
variable_name,
abort_message,
}
}
_ => syntax_error!(macro_name),
}
}
_ => syntax_error!(macro_name),
}
}