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#rust#proc-macro#http

git clone https://pyrossh.dev/repos/rust-embed.git
Discussions: https://groups.google.com/g/rust-embed-devs

rust macro which loads files into the rust binary at compile time during release and loads the file from the fs during dev.

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71637d93 — Mcat12

5 years ago 
Support a prefix annotation
Files changed (2) hide show
  1. impl/src/lib.rs +53 -30
  2. tests/prefix.rs +24 -0
impl/src/lib.rs CHANGED
@@ -6,9 +6,9 @@ extern crate proc_macro;
6
6
  use proc_macro::TokenStream;
7
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  use proc_macro2::TokenStream as TokenStream2;
8
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  use std::{env, path::Path};
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- use syn::{Data, DeriveInput, Fields, Lit, Meta};
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+ use syn::{Data, DeriveInput, Fields, Lit, Meta, MetaNameValue};
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- fn embedded(ident: &syn::Ident, folder_path: String) -> TokenStream2 {
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+ fn embedded(ident: &syn::Ident, folder_path: String, prefix: Option<&str>) -> TokenStream2 {
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  extern crate rust_embed_utils;
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13
 
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  let mut match_values = Vec::<TokenStream2>::new();
@@ -16,7 +16,12 @@ fn embedded(ident: &syn::Ident, folder_path: String) -> TokenStream2 {
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16
 
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  for rust_embed_utils::FileEntry { rel_path, full_canonical_path } in rust_embed_utils::get_files(folder_path) {
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  match_values.push(embed_file(&rel_path, &full_canonical_path));
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+
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- list_values.push(rel_path);
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+ list_values.push(if let Some(prefix) = prefix {
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+ format!("{}{}", prefix, rel_path)
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+ } else {
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+ rel_path
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+ });
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  }
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  let array_len = list_values.len();
@@ -29,10 +34,19 @@ fn embedded(ident: &syn::Ident, folder_path: String) -> TokenStream2 {
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  quote! { #[cfg(not(debug_assertions))]}
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35
  };
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36
 
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+ let handle_prefix = if let Some(prefix) = prefix {
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+ quote! {
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+ let file_path = file_path.strip_prefix(#prefix)?;
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+ }
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+ } else {
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+ TokenStream2::new()
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+ };
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+
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  quote! {
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  #not_debug_attr
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  impl #ident {
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  pub fn get(file_path: &str) -> Option<std::borrow::Cow<'static, [u8]>> {
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+ #handle_prefix
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  match file_path.replace("\\", "/").as_str() {
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  #(#match_values)*
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  _ => None,
@@ -61,7 +75,16 @@ fn embedded(ident: &syn::Ident, folder_path: String) -> TokenStream2 {
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  }
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  }
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77
 
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- fn dynamic(ident: &syn::Ident, folder_path: String) -> TokenStream2 {
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+ fn dynamic(ident: &syn::Ident, folder_path: String, prefix: Option<&str>) -> TokenStream2 {
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+ let (handle_prefix, map_iter) = if let Some(prefix) = prefix {
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+ (
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+ quote! { let file_path = file_path.strip_prefix(#prefix)?; },
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+ quote! { std::borrow::Cow::Owned(format!("{}{}", #prefix, e.rel_path)) },
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+ )
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+ } else {
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+ (TokenStream2::new(), quote! { std::borrow::Cow::from(e.rel_path) })
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+ };
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+
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  quote! {
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  #[cfg(debug_assertions)]
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  impl #ident {
@@ -69,6 +92,8 @@ fn dynamic(ident: &syn::Ident, folder_path: String) -> TokenStream2 {
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  use std::fs;
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  use std::path::Path;
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94
 
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+ #handle_prefix
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+
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  let file_path = Path::new(#folder_path).join(file_path.replace("\\", "/"));
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  match fs::read(file_path) {
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  Ok(contents) => Some(std::borrow::Cow::from(contents)),
@@ -80,7 +105,8 @@ fn dynamic(ident: &syn::Ident, folder_path: String) -> TokenStream2 {
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105
 
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  pub fn iter() -> impl Iterator<Item = std::borrow::Cow<'static, str>> {
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  use std::path::Path;
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- rust_embed::utils::get_files(String::from(#folder_path)).map(|e| std::borrow::Cow::from(e.rel_path))
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+ rust_embed::utils::get_files(String::from(#folder_path))
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+ .map(|e| #map_iter)
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  }
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  }
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112
 
@@ -97,13 +123,13 @@ fn dynamic(ident: &syn::Ident, folder_path: String) -> TokenStream2 {
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  }
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  }
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125
 
100
- fn generate_assets(ident: &syn::Ident, folder_path: String) -> TokenStream2 {
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+ fn generate_assets(ident: &syn::Ident, folder_path: String, prefix: Option<String>) -> TokenStream2 {
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- let embedded_impl = embedded(ident, folder_path.clone());
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+ let embedded_impl = embedded(ident, folder_path.clone(), prefix.as_deref());
102
128
  if cfg!(feature = "debug-embed") {
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  return embedded_impl;
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  }
105
131
 
106
- let dynamic_impl = dynamic(ident, folder_path);
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+ let dynamic_impl = dynamic(ident, folder_path, prefix.as_deref());
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133
 
108
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  quote! {
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  #embedded_impl
@@ -112,9 +138,9 @@ fn generate_assets(ident: &syn::Ident, folder_path: String) -> TokenStream2 {
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138
  }
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139
 
114
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  #[cfg(not(feature = "compression"))]
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- fn embed_file(rel_path: &str, full_canonical_path: &str) -> TokenStream2 {
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+ fn embed_file(match_str: &str, full_canonical_path: &str) -> TokenStream2 {
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142
  quote! {
117
- #rel_path => {
143
+ #match_str => {
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  let bytes = &include_bytes!(#full_canonical_path)[..];
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  Some(std::borrow::Cow::from(bytes))
120
146
  },
@@ -133,6 +159,19 @@ fn embed_file(rel_path: &str, full_canonical_path: &str) -> TokenStream2 {
133
159
  }
134
160
  }
135
161
 
162
+ /// Find a `name = "value"` attribute from the derive input
163
+ fn find_attribute_value(ast: &syn::DeriveInput, attr_name: &str) -> Option<String> {
164
+ ast
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+ .attrs
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+ .iter()
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+ .find(|value| value.path.is_ident(attr_name))
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+ .and_then(|attr| attr.parse_meta().ok())
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+ .and_then(|meta| match meta {
170
+ Meta::NameValue(MetaNameValue { lit: Lit::Str(val), .. }) => Some(val.value()),
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+ _ => None,
172
+ })
173
+ }
174
+
136
175
  fn impl_rust_embed(ast: &syn::DeriveInput) -> TokenStream2 {
137
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  match ast.data {
138
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  Data::Struct(ref data) => match data.fields {
@@ -142,24 +181,8 @@ fn impl_rust_embed(ast: &syn::DeriveInput) -> TokenStream2 {
142
181
  _ => panic!("RustEmbed can only be derived for unit structs"),
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182
  };
144
183
 
145
- let attribute = ast
146
- .attrs
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- .iter()
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- .find(|value| value.path.is_ident("folder"))
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- .expect("#[derive(RustEmbed)] should contain one attribute like this #[folder = \"examples/public/\"]");
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- let meta = attribute
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- .parse_meta()
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- .expect("#[derive(RustEmbed)] should contain one attribute like this #[folder = \"examples/public/\"]");
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- let literal_value = match meta {
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- Meta::NameValue(ref data) => &data.lit,
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- _ => panic!("#[derive(RustEmbed)] should contain one attribute like this #[folder = \"examples/public/\"]"),
184
+ let folder_path = find_attribute_value(ast, "folder").expect("#[derive(RustEmbed)] should contain one attribute like this #[folder = \"examples/public/\"]");
156
- };
157
- let folder_path = match literal_value {
158
- Lit::Str(ref val) => val.clone().value(),
159
- _ => {
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- panic!("#[derive(RustEmbed)] attribute value must be a string literal");
185
+ let prefix = find_attribute_value(ast, "prefix");
161
- }
162
- };
163
186
 
164
187
  #[cfg(feature = "interpolate-folder-path")]
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188
  let folder_path = shellexpand::full(&folder_path).unwrap().to_string();
@@ -192,10 +215,10 @@ fn impl_rust_embed(ast: &syn::DeriveInput) -> TokenStream2 {
192
215
  panic!(message);
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  };
194
217
 
195
- generate_assets(&ast.ident, folder_path)
218
+ generate_assets(&ast.ident, folder_path, prefix)
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219
  }
197
220
 
198
- #[proc_macro_derive(RustEmbed, attributes(folder))]
221
+ #[proc_macro_derive(RustEmbed, attributes(folder, prefix))]
199
222
  pub fn derive_input_object(input: TokenStream) -> TokenStream {
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223
  let ast: DeriveInput = syn::parse(input).unwrap();
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  let gen = impl_rust_embed(&ast);
tests/prefix.rs ADDED
@@ -0,0 +1,24 @@
1
+ use rust_embed::RustEmbed;
2
+
3
+ #[derive(RustEmbed)]
4
+ #[folder = "examples/public/"]
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+ #[prefix = "prefix/"]
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+ struct Asset;
7
+
8
+ #[test]
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+ fn get_with_prefix() {
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+ assert!(Asset::get("prefix/index.html").is_some());
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+ }
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+
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+ #[test]
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+ fn get_without_prefix() {
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+ assert!(Asset::get("index.html").is_none());
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+ }
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+
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+ #[test]
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+ fn iter_values_have_prefix() {
20
+ for file in Asset::iter() {
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+ assert!(file.starts_with("prefix/"));
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+ assert!(Asset::get(file.as_ref()).is_some());
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+ }
24
+ }