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
extern crate proc_macro;

use quote::quote;
use syn::parse_macro_input;

mod id;

/// A data structure representing a Solana account, implementing various traits:
///
/// - [`AccountSerialize`](./trait.AccountSerialize.html)
/// - [`AccountDeserialize`](./trait.AccountDeserialize.html)
/// - [`AnchorSerialize`](./trait.AnchorSerialize.html)
/// - [`AnchorDeserialize`](./trait.AnchorDeserialize.html)
///
/// When implementing account serialization traits the first 8 bytes are
/// reserved for a unique account discriminator, self described by the first 8
/// bytes of the SHA256 of the account's Rust ident.
///
/// As a result, any calls to `AccountDeserialize`'s `try_deserialize` will
/// check this discriminator. If it doesn't match, an invalid account was given,
/// and the account deserialization will exit with an error.
///
/// # Zero Copy Deserialization
///
/// **WARNING**: Zero copy deserialization is an experimental feature. It's
/// recommended to use it only when necessary, i.e., when you have extremely
/// large accounts that cannot be Borsh deserialized without hitting stack or
/// heap limits.
///
/// ## Usage
///
/// To enable zero-copy-deserialization, one can pass in the `zero_copy`
/// argument to the macro as follows:
///
/// ```ignore
/// #[account(zero_copy)]
/// ```
///
/// This can be used to conveniently implement
/// [`ZeroCopy`](./trait.ZeroCopy.html) so that the account can be used
/// with [`Loader`](./struct.Loader.html).
///
/// Other than being more efficient, the most salient benefit this provides is
/// the ability to define account types larger than the max stack or heap size.
/// When using borsh, the account has to be copied and deserialized into a new
/// data structure and thus is constrained by stack and heap limits imposed by
/// the BPF VM. With zero copy deserialization, all bytes from the account's
/// backing `RefCell<&mut [u8]>` are simply re-interpreted as a reference to
/// the data structure. No allocations or copies necessary. Hence the ability
/// to get around stack and heap limitations.
///
/// To facilitate this, all fields in an account must be constrained to be
/// "plain old  data", i.e., they must implement
/// [`Pod`](../bytemuck/trait.Pod.html). Please review the
/// [`safety`](file:///home/armaniferrante/Documents/code/src/github.com/project-serum/anchor/target/doc/bytemuck/trait.Pod.html#safety)
/// section before using.
#[proc_macro_attribute]
pub fn account(
    args: proc_macro::TokenStream,
    input: proc_macro::TokenStream,
) -> proc_macro::TokenStream {
    let mut namespace = "".to_string();
    let mut is_zero_copy = false;
    if args.to_string().split(',').count() > 2 {
        panic!("Only two args are allowed to the account attribute.")
    }
    for arg in args.to_string().split(',') {
        let ns = arg
            .to_string()
            .replace("\"", "")
            .chars()
            .filter(|c| !c.is_whitespace())
            .collect();
        if ns == "zero_copy" {
            is_zero_copy = true;
        } else {
            namespace = ns;
        }
    }

    let account_strct = parse_macro_input!(input as syn::ItemStruct);
    let account_name = &account_strct.ident;
    let (impl_gen, type_gen, where_clause) = account_strct.generics.split_for_impl();

    let discriminator: proc_macro2::TokenStream = {
        // Namespace the discriminator to prevent collisions.
        let discriminator_preimage = {
            // For now, zero copy accounts can't be namespaced.
            if namespace.is_empty() {
                format!("account:{}", account_name.to_string())
            } else {
                format!("{}:{}", namespace, account_name.to_string())
            }
        };

        let mut discriminator = [0u8; 8];
        discriminator.copy_from_slice(
            &anchor_syn::hash::hash(discriminator_preimage.as_bytes()).to_bytes()[..8],
        );
        format!("{:?}", discriminator).parse().unwrap()
    };

    let owner_impl = {
        if namespace.is_empty() {
            quote! {
                #[automatically_derived]
                impl #impl_gen anchor_lang::Owner for #account_name #type_gen #where_clause {
                    fn owner() -> Pubkey {
                        crate::ID
                    }
                }
            }
        } else {
            quote! {}
        }
    };

    proc_macro::TokenStream::from({
        if is_zero_copy {
            quote! {
                #[zero_copy]
                #account_strct

                #[automatically_derived]
                unsafe impl #impl_gen anchor_lang::__private::bytemuck::Pod for #account_name #type_gen #where_clause {}
                #[automatically_derived]
                unsafe impl #impl_gen anchor_lang::__private::bytemuck::Zeroable for #account_name #type_gen #where_clause {}

                #[automatically_derived]
                impl #impl_gen anchor_lang::ZeroCopy for #account_name #type_gen #where_clause {}

                #[automatically_derived]
                impl #impl_gen anchor_lang::Discriminator for #account_name #type_gen #where_clause {
                    fn discriminator() -> [u8; 8] {
                        #discriminator
                    }
                }

                // This trait is useful for clients deserializing accounts.
                // It's expected on-chain programs deserialize via zero-copy.
                #[automatically_derived]
                impl #impl_gen anchor_lang::AccountDeserialize for #account_name #type_gen #where_clause {
                    fn try_deserialize(buf: &mut &[u8]) -> std::result::Result<Self, ProgramError> {
                        if buf.len() < #discriminator.len() {
                            return Err(anchor_lang::__private::ErrorCode::AccountDiscriminatorNotFound.into());
                        }
                        let given_disc = &buf[..8];
                        if &#discriminator != given_disc {
                            return Err(anchor_lang::__private::ErrorCode::AccountDiscriminatorMismatch.into());
                        }
                        Self::try_deserialize_unchecked(buf)
                    }

                    fn try_deserialize_unchecked(buf: &mut &[u8]) -> std::result::Result<Self, ProgramError> {
                        let data: &[u8] = &buf[8..];
                        // Re-interpret raw bytes into the POD data structure.
                        let account = anchor_lang::__private::bytemuck::from_bytes(data);
                        // Copy out the bytes into a new, owned data structure.
                        Ok(*account)
                    }
                }

                #owner_impl
            }
        } else {
            quote! {
                #[derive(AnchorSerialize, AnchorDeserialize, Clone)]
                #account_strct

                #[automatically_derived]
                impl #impl_gen anchor_lang::AccountSerialize for #account_name #type_gen #where_clause {
                    fn try_serialize<W: std::io::Write>(&self, writer: &mut W) -> std::result::Result<(), ProgramError> {
                        writer.write_all(&#discriminator).map_err(|_| anchor_lang::__private::ErrorCode::AccountDidNotSerialize)?;
                        AnchorSerialize::serialize(
                            self,
                            writer
                        )
                            .map_err(|_| anchor_lang::__private::ErrorCode::AccountDidNotSerialize)?;
                        Ok(())
                    }
                }

                #[automatically_derived]
                impl #impl_gen anchor_lang::AccountDeserialize for #account_name #type_gen #where_clause {
                    fn try_deserialize(buf: &mut &[u8]) -> std::result::Result<Self, ProgramError> {
                        if buf.len() < #discriminator.len() {
                            return Err(anchor_lang::__private::ErrorCode::AccountDiscriminatorNotFound.into());
                        }
                        let given_disc = &buf[..8];
                        if &#discriminator != given_disc {
                            return Err(anchor_lang::__private::ErrorCode::AccountDiscriminatorMismatch.into());
                        }
                        Self::try_deserialize_unchecked(buf)
                    }

                    fn try_deserialize_unchecked(buf: &mut &[u8]) -> std::result::Result<Self, ProgramError> {
                        let mut data: &[u8] = &buf[8..];
                        AnchorDeserialize::deserialize(&mut data)
                            .map_err(|_| anchor_lang::__private::ErrorCode::AccountDidNotDeserialize.into())
                    }
                }

                #[automatically_derived]
                impl #impl_gen anchor_lang::Discriminator for #account_name #type_gen #where_clause {
                    fn discriminator() -> [u8; 8] {
                        #discriminator
                    }
                }

                #owner_impl
            }
        }
    })
}

#[proc_macro_derive(ZeroCopyAccessor, attributes(accessor))]
pub fn derive_zero_copy_accessor(item: proc_macro::TokenStream) -> proc_macro::TokenStream {
    let account_strct = parse_macro_input!(item as syn::ItemStruct);
    let account_name = &account_strct.ident;
    let (impl_gen, ty_gen, where_clause) = account_strct.generics.split_for_impl();

    let fields = match &account_strct.fields {
        syn::Fields::Named(n) => n,
        _ => panic!("Fields must be named"),
    };
    let methods: Vec<proc_macro2::TokenStream> = fields
        .named
        .iter()
        .filter_map(|field: &syn::Field| {
            field
                .attrs
                .iter()
                .find(|attr| anchor_syn::parser::tts_to_string(&attr.path) == "accessor")
                .map(|attr| {
                    let mut tts = attr.tokens.clone().into_iter();
                    let g_stream = match tts.next().expect("Must have a token group") {
                        proc_macro2::TokenTree::Group(g) => g.stream(),
                        _ => panic!("Invalid syntax"),
                    };
                    let accessor_ty = match g_stream.into_iter().next() {
                        Some(token) => token,
                        _ => panic!("Missing accessor type"),
                    };

                    let field_name = field.ident.as_ref().unwrap();

                    let get_field: proc_macro2::TokenStream =
                        format!("get_{}", field_name.to_string()).parse().unwrap();
                    let set_field: proc_macro2::TokenStream =
                        format!("set_{}", field_name.to_string()).parse().unwrap();

                    quote! {
                        pub fn #get_field(&self) -> #accessor_ty {
                            anchor_lang::__private::ZeroCopyAccessor::get(&self.#field_name)
                        }
                        pub fn #set_field(&mut self, input: &#accessor_ty) {
                            self.#field_name = anchor_lang::__private::ZeroCopyAccessor::set(input);
                        }
                    }
                })
        })
        .collect();
    proc_macro::TokenStream::from(quote! {
        #[automatically_derived]
        impl #impl_gen #account_name #ty_gen #where_clause {
            #(#methods)*
        }
    })
}

/// A data structure that can be used as an internal field for a zero copy
/// deserialized account, i.e., a struct marked with `#[account(zero_copy)]`.
///
/// This is just a convenient alias for
///
/// ```ignore
/// #[derive(Copy, Clone)]
/// #[repr(packed)]
/// struct MyStruct {...}
/// ```
#[proc_macro_attribute]
pub fn zero_copy(
    _args: proc_macro::TokenStream,
    item: proc_macro::TokenStream,
) -> proc_macro::TokenStream {
    let account_strct = parse_macro_input!(item as syn::ItemStruct);

    proc_macro::TokenStream::from(quote! {
        #[derive(anchor_lang::__private::ZeroCopyAccessor, Copy, Clone)]
        #[repr(packed)]
        #account_strct
    })
}

/// Defines the program's ID. This should be used at the root of all Anchor
/// based programs.
#[proc_macro]
pub fn declare_id(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
    let id = parse_macro_input!(input as id::Id);
    proc_macro::TokenStream::from(quote! {#id})
}