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use path;
use std::borrow::Cow;
use std::path::PathBuf;
use syn;
pub struct TemplateInput<'a> {
pub ast: &'a syn::DeriveInput,
pub meta: TemplateMeta<'a>,
pub path: PathBuf,
pub source: Cow<'a, str>,
}
impl<'a> TemplateInput<'a> {
pub fn new(ast: &'a syn::DeriveInput) -> TemplateInput<'a> {
let meta = TemplateMeta::new(ast);
let (path, source) = match meta.source {
Source::Source(s) => (PathBuf::new(), Cow::Borrowed(s)),
Source::Path(s) => {
let path = path::find_template_from_path(&s, None);
let src = path::get_template_source(&path);
(path, Cow::Owned(src))
},
};
TemplateInput { ast, meta, path, source }
}
}
// Holds metadata for the template, based on the `template()` attribute.
pub struct TemplateMeta<'a> {
source: Source<'a>,
pub print: Print,
}
impl<'a> TemplateMeta<'a> {
fn new(ast: &'a syn::DeriveInput) -> TemplateMeta<'a> {
let attr = ast.attrs.iter().find(|a| a.name() == "template");
if attr.is_none() {
let msg = format!("'template' attribute not found on struct '{}'",
ast.ident.as_ref());
panic!(msg);
}
let attr = attr.unwrap();
let mut source = None;
let mut print = Print::None;
if let syn::MetaItem::List(_, ref inner) = attr.value {
for nm_item in inner {
if let syn::NestedMetaItem::MetaItem(ref item) = *nm_item {
if let syn::MetaItem::NameValue(ref key, ref val) = *item {
match key.as_ref() {
"path" => if let syn::Lit::Str(ref s, _) = *val {
source = Some(Source::Path(s.as_ref()));
} else {
panic!("template path must be string literal");
},
"source" => if let syn::Lit::Str(ref s, _) = *val {
source = Some(Source::Source(s.as_ref()));
} else {
panic!("template source must be string literal");
},
"print" => if let syn::Lit::Str(ref s, _) = *val {
print = s.into();
} else {
panic!("print value must be string literal");
},
_ => { panic!("unsupported annotation key found") }
}
}
}
}
}
match source {
Some(s) => TemplateMeta { source: s, print },
None => panic!("template path or source not found in struct attributes"),
}
}
}
enum Source<'a> {
Path(&'a str),
Source(&'a str),
}
#[derive(PartialEq)]
pub enum Print {
All,
Ast,
Code,
None,
}
impl<'a> From<&'a String> for Print {
fn from(s: &'a String) -> Print {
use self::Print::*;
match s.as_ref() {
"all" => All,
"ast" => Ast,
"code" => Code,
"none" => None,
v => panic!("invalid value for print option: {}", v),
}
}
}
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