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

use core::marker::PhantomData;

use crate::{
    api::{
        const_handles, use_raw_handle, ErrorApi, ErrorApiImpl, ManagedBufferApiImpl,
        ManagedTypeApi, StaticVarApiImpl, StorageReadApi, StorageReadApiImpl,
    },
    codec::*,
    err_msg,
    types::{
        BigInt, BigUint, ManagedBuffer, ManagedBufferNestedDecodeInput, ManagedRef, ManagedType,
    },
};
use alloc::boxed::Box;

use super::StorageKey;

struct StorageGetInput<'k, A>
where
    A: StorageReadApi + ManagedTypeApi + ErrorApi + 'static,
{
    key: ManagedRef<'k, A, StorageKey<A>>,
}

impl<'k, A> StorageGetInput<'k, A>
where
    A: StorageReadApi + ManagedTypeApi + ErrorApi + 'static,
{
    #[inline]
    fn new(key: ManagedRef<'k, A, StorageKey<A>>) -> Self {
        StorageGetInput { key }
    }

    fn to_managed_buffer(&self) -> ManagedBuffer<A> {
        let mbuf_handle: A::ManagedBufferHandle =
            use_raw_handle(A::static_var_api_impl().next_handle());
        A::storage_read_api_impl()
            .storage_load_managed_buffer_raw(self.key.buffer.get_handle(), mbuf_handle.clone());
        ManagedBuffer::from_handle(mbuf_handle)
    }

    fn to_big_uint(&self) -> BigUint<A> {
        BigUint::from_bytes_be_buffer(&self.to_managed_buffer())
    }

    fn to_big_int(&self) -> BigInt<A> {
        BigInt::from_signed_bytes_be_buffer(&self.to_managed_buffer())
    }

    fn load_len_managed_buffer(&self) -> usize {
        let value_handle: A::ManagedBufferHandle = use_raw_handle(const_handles::MBUF_TEMPORARY_1);
        A::storage_read_api_impl()
            .storage_load_managed_buffer_raw(self.key.buffer.get_handle(), value_handle.clone());
        A::managed_type_impl().mb_len(value_handle)
    }
}

impl<'k, A> TopDecodeInput for StorageGetInput<'k, A>
where
    A: StorageReadApi + ManagedTypeApi + ErrorApi + 'static,
{
    type NestedBuffer = ManagedBufferNestedDecodeInput<A>;

    fn byte_len(&self) -> usize {
        self.load_len_managed_buffer()
    }

    fn into_boxed_slice_u8(self) -> Box<[u8]> {
        self.to_managed_buffer().to_boxed_bytes().into_box()
    }

    #[inline]
    fn into_max_size_buffer<H, const MAX_LEN: usize>(
        self,
        buffer: &mut [u8; MAX_LEN],
        h: H,
    ) -> Result<&[u8], H::HandledErr>
    where
        H: DecodeErrorHandler,
    {
        self.to_managed_buffer().into_max_size_buffer(buffer, h)
    }

    #[inline]
    fn supports_specialized_type<T: TryStaticCast>() -> bool {
        T::type_eq::<ManagedBuffer<A>>() || T::type_eq::<BigUint<A>>() || T::type_eq::<BigInt<A>>()
    }

    #[inline]
    fn into_specialized<T, H>(self, h: H) -> Result<T, H::HandledErr>
    where
        T: TryStaticCast,
        H: DecodeErrorHandler,
    {
        if let Some(result) = try_execute_then_cast(|| self.to_managed_buffer()) {
            Ok(result)
        } else if let Some(result) = try_execute_then_cast(|| self.to_big_uint()) {
            Ok(result)
        } else if let Some(result) = try_execute_then_cast(|| self.to_big_int()) {
            Ok(result)
        } else {
            Err(h.handle_error(DecodeError::UNSUPPORTED_OPERATION))
        }
    }

    fn into_nested_buffer(self) -> Self::NestedBuffer {
        ManagedBufferNestedDecodeInput::new(self.to_managed_buffer())
    }
}

pub fn storage_get<A, T>(key: ManagedRef<'_, A, StorageKey<A>>) -> T
where
    T: TopDecode,
    A: StorageReadApi + ManagedTypeApi + ErrorApi,
{
    let Ok(value) = T::top_decode_or_handle_err(
        StorageGetInput::new(key),
        StorageGetErrorHandler::<A>::default(),
    );
    value
}

/// Useful for storage mappers.
/// Also calls to it generated by macro.
pub fn storage_get_len<A>(key: ManagedRef<'_, A, StorageKey<A>>) -> usize
where
    A: StorageReadApi + ManagedTypeApi + ErrorApi,
{
    let input = StorageGetInput::new(key);
    input.load_len_managed_buffer()
}

/// Will immediately end the execution when encountering the first decode error, via `signal_error`.
/// Because its handled error type is the never type, when compiled,
/// the codec will return the value directly, without wrapping it in a Result.
#[derive(Clone)]
pub(crate) struct StorageGetErrorHandler<M>
where
    M: ManagedTypeApi + ErrorApi,
{
    _phantom: PhantomData<M>,
}

impl<M> Copy for StorageGetErrorHandler<M> where M: ManagedTypeApi + ErrorApi {}

impl<M> Default for StorageGetErrorHandler<M>
where
    M: ManagedTypeApi + ErrorApi,
{
    fn default() -> Self {
        Self {
            _phantom: PhantomData,
        }
    }
}

impl<M> DecodeErrorHandler for StorageGetErrorHandler<M>
where
    M: ManagedTypeApi + ErrorApi,
{
    type HandledErr = !;

    fn handle_error(&self, err: DecodeError) -> Self::HandledErr {
        let mut message_buffer = ManagedBuffer::<M>::new_from_bytes(err_msg::STORAGE_DECODE_ERROR);
        message_buffer.append_bytes(err.message_bytes());
        M::error_api_impl().signal_error_from_buffer(message_buffer.get_handle())
    }
}