1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
extern crate proc_macro;
use proc_macro2::TokenStream;
use quote::quote;
use std::str::FromStr;
use syn::Meta::Word;
use syn::NestedMeta::Meta;
use syn::{parse_macro_input, Data, DeriveInput, Fields, Ident, Type};
use crate::attr::*;
use crate::utils::*;
#[derive(Default)]
struct BinarySerializeTokens {
pub serialize: TokenStream,
pub serialized_size: Option<TokenStream>,
pub min_nonzero_elements_size: Option<TokenStream>,
}
impl BinarySerializeTokens {
fn new(serialize: TokenStream, serialized_size: Option<TokenStream>, min_nonzero_elements_size: Option<TokenStream>) -> BinarySerializeTokens {
BinarySerializeTokens {
serialize,
serialized_size,
min_nonzero_elements_size,
}
}
}
pub(crate) fn binary_serialize_helper(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
let input = parse_macro_input!(input as DeriveInput);
let mut use_inner_member_serialized_size = true;
let mut static_serialized_size: Option<usize> = None;
if !input.attrs.is_empty() {
for attr in &input.attrs {
if attr.path.segments[0].ident == "serialized_size" {
let meta = attr.parse_meta().expect("couldn't parse meta");
if let syn::Meta::List(l) = meta {
if l.nested.len() > 1 {
panic!("only expected 1 item in serialized_size");
}
let nested = &l.nested[0];
if let syn::NestedMeta::Literal(lit) = nested {
if let syn::Lit::Int(int) = lit {
static_serialized_size = Some(int.value() as usize);
use_inner_member_serialized_size = false;
}
}
}
}
}
}
let name = input.ident;
let name_as_string = name.to_string();
let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
let tokens = serialize_fields(&name, &input.data, use_inner_member_serialized_size);
let serialize = tokens.serialize;
let serialized_size = if let Some(size) = static_serialized_size {
quote! {#size}
} else if let Some(ref serialized_size) = tokens.serialized_size {
serialized_size.clone()
} else {
quote! {std::mem::size_of_val(&self.to_primitive());}
};
let min_nonzero_elements_size = tokens.min_nonzero_elements_size.unwrap();
let serialized_size = quote! {
impl #impl_generics ::lain::traits::SerializedSize for #name #ty_generics #where_clause {
#[inline(always)]
fn serialized_size(&self) -> usize {
use ::lain::traits::SerializedSize;
::lain::log::debug!("getting serialized size of {}", #name_as_string);
let size = #serialized_size;
::lain::log::debug!("size of {} is 0x{:02X}", #name_as_string, size);
return size;
}
#[inline(always)]
fn min_nonzero_elements_size() -> usize {
#min_nonzero_elements_size
}
}
};
// println!("{}", serialized_size);
let expanded = quote! {
impl #impl_generics ::lain::traits::BinarySerialize for #name #ty_generics #where_clause {
fn binary_serialize<W: std::io::Write, E: ::lain::byteorder::ByteOrder>(&self, buffer: &mut W) {
use ::lain::traits::SerializedSize;
use ::lain::byteorder::{LittleEndian, BigEndian, WriteBytesExt};
#serialize
}
}
#serialized_size
};
// Uncomment to dump the AST
// println!("{}", expanded);
proc_macro::TokenStream::from(expanded)
}
fn serialize_fields(
name: &Ident,
data: &Data,
use_inner_member_serialized_size: bool,
) -> BinarySerializeTokens {
match *data {
Data::Enum(ref data) => {
let mut variant_branches = Vec::<TokenStream>::new();
let mut serialized_size_variant_branches = Vec::<TokenStream>::new();
let mut min_sizes = Vec::<TokenStream>::new();
for variant in data.variants.iter() {
let ident = &variant.ident;
let full_ident_string = format!("{}::{}", &name.to_string(), &ident.to_string());
let full_ident = TokenStream::from_str(&full_ident_string).unwrap();
let mut parameters = TokenStream::new();
match variant.fields {
syn::Fields::Unnamed(ref fields) => {
let mut serialized_fields = TokenStream::new();
let mut total_size = TokenStream::new();
let mut variant_sizes = Vec::<TokenStream>::new();
// iterate over every item in this tuple
for (i, ref unnamed) in fields.unnamed.iter().enumerate() {
let field_ty = &unnamed.ty;
let ident = TokenStream::from_str(&format!("field_{}", i)).unwrap();
total_size.extend(quote! {total_size += #ident.serialized_size();});
variant_sizes.push(quote!{std::mem::size_of::<#field_ty>()});
serialized_fields.extend(quote! {
#ident.binary_serialize::<_, E>(buffer);
});
parameters.extend(quote! {ref #ident,});
}
min_sizes.push(quote!{0#(+#variant_sizes)*});
let serialized_size = if use_inner_member_serialized_size {
quote! {
let serialized_size = total_size;
}
} else {
quote! {
let serialized_size = self.serialized_size();
}
};
let trailer = quote! {
let padding = serialized_size - total_size;
if padding != 0 {
let padding_data: Vec<u8> = (0..padding).map(|_| 0).collect();
buffer.write(&padding_data).ok();
}
};
variant_branches.push(quote!{
#full_ident(#parameters) => {
let mut total_size = 0;
#total_size
#serialized_size
// TODO: we technically handle multiple fields, but this is hardcoded
if total_size > serialized_size {
panic!("size of serialized data for {} will be greater than enum's marked size ({} > {})", #full_ident_string, total_size, serialized_size);
}
#serialized_fields
#trailer
},
});
serialized_size_variant_branches.push(quote! {
#full_ident(#parameters) => {
let mut total_size = 0;
#total_size
#serialized_size
serialized_size
},
});
//println!("{}", variant_branches[variant_branches.len() - 1]);
}
syn::Fields::Unit => {
let serialize = quote! {
self.to_primitive().binary_serialize::<_, E>(buffer);
};
let size = quote! {
std::mem::size_of::<#name>();
};
let min_size = quote! {
std::mem::size_of::<#name>()
};
return BinarySerializeTokens::new(serialize, Some(size), Some(min_size));
}
_ => panic!("unsupported enum type (probably contains named members)"),
}
}
let serialize_body = quote! {
match *self {
#(#variant_branches)*
}
};
let serialized_size_body = quote! {
match *self {
#(#serialized_size_variant_branches)*
}
};
let sizes = quote!{*[#(#min_sizes,)*].iter().min_by(|a, b| a.cmp(b)).unwrap()};
BinarySerializeTokens::new(serialize_body, Some(serialized_size_body), Some(sizes))
}
Data::Struct(ref data) => {
match data.fields {
Fields::Named(ref fields) => {
let mut bitfield_shift = 0;
let mut bitfield_type: Option<TokenStream> = None;
let fields = fields.named.iter().map(|f| {
let name = &f.ident;
let ty = &f.ty;
// parse out the byteorder
let meta = f.attrs.iter().filter_map(get_byteorder_metadata);
let field_byteorder = get_byteorder(meta);
let meta = f.attrs.iter().filter_map(get_bitfield_metadata);
// this is a bitfield. we need to use our "bitfield" local variable
// to temporarily hold all these bits
let bitfield_meta = get_bitfield_limits(meta);
let is_bitfield = bitfield_meta.is_some();
if is_bitfield {
let primitive_type = match ty {
Type::Path(ref p) if !p.path.segments.is_empty() => {
let base_type = p.path.segments[0].ident.to_string();
is_primitive(&base_type)
}
_ => {
panic!("bitfields are only supported for paths -- arrays should not be used");
}
};
let bitfield_meta = bitfield_meta.unwrap();
let old_shift = bitfield_shift;
let num_bits = bitfield_meta.bit_count;
bitfield_shift += num_bits;
bitfield_type = bitfield_meta.ty;
let bit_mask = 2_u64.pow(num_bits as u32) - 1;
// TODO: Min/max validation
let mut text = match primitive_type {
PrimitiveType::Number => {
quote! {
bitfield |= ((self.#name as #bitfield_type & #bit_mask as #bitfield_type) << #old_shift) as u64;
}
}
_ => {
quote! {
bitfield |= (((self.#name.to_primitive() as u64) & (#bit_mask as u64)) << #old_shift) as u64;
}
}
};
if bitfield_meta.ty_bits == bitfield_shift {
text.extend(quote!{
(bitfield as #bitfield_type).binary_serialize::<_, E>(buffer);
bitfield = 0;
});
bitfield_shift = 0;
}
let size = if old_shift == 0 {
Some(quote! {
std::mem::size_of::<#bitfield_type>()
})
} else {
None
};
return BinarySerializeTokens::new(text, size.clone(), size);
}
fn handle_type(name: &syn::Ident, ty: &syn::Type, field_byteorder: Option<&TokenStream>) -> BinarySerializeTokens {
let handle_ident = |ty: &syn::Path| {
let root = &ty.segments[0].ident;
let primitive_type = is_primitive(&root.to_string());
let size = match primitive_type {
PrimitiveType::Number | PrimitiveType::Bool => {
quote! {
std::mem::size_of::<#ty>()
}
},
_ => {
quote! {
self.#name.serialized_size()
}
}
};
let min_size = match primitive_type {
PrimitiveType::Number | PrimitiveType::Bool => {
quote! {
std::mem::size_of::<#ty>()
}
},
_ => {
quote! {
<#ty>::min_nonzero_elements_size()
}
}
};
// If the field has a custom byteorder to override however the parent
// is serialized, we handle that here
if field_byteorder.is_some() {
let binary_serialize_text = quote!{
self.#name.binary_serialize::<_, #field_byteorder>(buffer);
};
return BinarySerializeTokens::new(binary_serialize_text, Some(size), None);
}
let binary_serialize_text = quote!{
self.#name.binary_serialize::<_, E>(buffer);
};
BinarySerializeTokens::new(binary_serialize_text, Some(size), Some(min_size))
};
match ty {
Type::Path(ref p) if !p.path.segments.is_empty() => {
handle_ident(&p.path)
}
Type::Array(a) => {
let array_len = &a.len;
let mut tokens = handle_type(&name, &a.elem, field_byteorder);
let per_item_serialized_size = tokens.serialized_size;
let per_item_min = tokens.min_nonzero_elements_size;
// use fold to avoid breaking the line
tokens.serialized_size = Some(quote! {
self.#name.iter().fold(0, |sum, i| sum + #per_item_serialized_size)
});
tokens.min_nonzero_elements_size = Some(quote!{
#per_item_min * #array_len
});
tokens
},
Type::Reference(ref reference) => {
handle_type(&name, &reference.elem, field_byteorder)
}
_ => {
panic!("Unsupported type");
}
}
}
handle_type(&name.as_ref().unwrap(), &ty, field_byteorder.as_ref())
});
let mut serialize_text = quote! {
// may not be used in all scenarios
let mut bitfield: u64 = 0;
};
let mut object_size = quote! {0};
let mut min_object_size = quote! {0};
for item in fields {
serialize_text.extend(item.serialize);
let item_size = item.serialized_size;
if item_size.is_some() {
object_size.extend(quote! {
+ #item_size
});
}
if let Some(ref min_size) = item.min_nonzero_elements_size {
min_object_size.extend(quote!{
+ #min_size
});
}
}
// the above case would not push the byte if there is
// a bitfield in the final position with padding
if bitfield_shift != 0 {
serialize_text.extend(quote! {
(bitfield as #bitfield_type).binary_serialize::<_, E>(buffer);
bitfield = 0;
});
}
BinarySerializeTokens::new(serialize_text, Some(object_size), Some(min_object_size))
}
_ => {
panic!("BinarySerializer only supports named fields");
}
}
}
_ => {
panic!("BinarySerializer is only supported for structs");
}
}
}
/// Returns the user-specified byteorder of a child field based off of the #[byteorder()] attribute.
/// This will return an Option<TokenStream> consisting of the full path to the byteorder::BigEndian or
/// byteorder::LittleEndian enum.
fn get_byteorder(meta: impl Iterator<Item = Vec<syn::NestedMeta>>) -> Option<TokenStream> {
for meta_items in meta {
for meta_item in meta_items {
match meta_item {
Meta(ref m) => match m {
Word(ref w) => {
match w.to_string().as_ref() {
"big" => return Some(quote! {::lain::byteorder::BigEndian}),
"little" => return Some(quote! {::lain::byteorder::LittleEndian}),
_ => panic!(
"{} is not a supported byteorder. must be big or little",
w.to_string()
),
};
}
_ => panic!("non-string literal for byteorder attribute"),
},
_ => panic!(
"#[byteorder] attribute expects a string literal (e.g. #[byteorder(big)]"
),
}
}
}
None
}
fn get_byteorder_metadata(attr: &syn::Attribute) -> Option<Vec<syn::NestedMeta>> {
get_attribute_metadata("byteorder", &attr)
}